DEVELOPMENT AND EVALUATION
OF INSTANT OMELETTE MIX WITH
EGG AND WHEY POWDER
K . V. V. S. RAJANI KUMAR
B.sc. (DairyTechnology)
MASTER OF SCIENCE
(FOOD TECHNOLOGY)
2016
DEVELOPMENT AND EVALUATION OF
INSTANT OMELETTE MIX WITH EGG AND
WHEY POWDER
BY
K . V. V. S. RAJANI KUMAR
B.sc. (Dairy Technology)
THESIS SUBMITTED TO THEPROFESSOR JAYASHANKAR
TELANGANA STATE AGRICULTURAL UNIVERSITY IN PARTIAL
FULFILMENT OF THE REQUIREMENTSFOR THE AWARD OF
THE DEGREE OF
MASTER OF SCIENCE
(FOOD TECHNOLOGY)
CHAIR PERSON: Dr. V.VIJAYALAKSHMI
POST GRADUATE AND RESEARCH CENTRE
INTERFACULTY PG PROGRAMME IN FOOD TECHNOLOGY
PROFESSOR JAYASHANKAR TELANGANA STATE
AGRICULTURAL UNIVERSITY, RAJENDRANAGAR,
HYDERABAD – 500 030.
2016
DECLARATION
I, K. V. V. S. RAJANI KUMAR, hereby declare that the thesis entitled
“DEVELOPMENT AND EVALUATION OF INSTANT OMELETTE MIX WITH EGG
AND WHEY POWDER." Submitted to Professor Jayashankar Telangana State
Agricultural University for the degree of Master of Science in Food Technology is the
result of original research work done by me. I also declare that no material contained in the
thesis has been published earlier in any manner.
Place :
K. V. V. S. RAJANI KUMAR
Date :
I.D. NO. FST-2013-001
CERTIFICATE
Mr. K. V. V. S. RAJANI KUMAR has satisfactorily prosecuted the course of
research and that thesis entitled “DEVELOPMENT AND EVALUATION OF INSTANT
OMELETTE MIX WITH EGG AND WHEY POWDER” submitted is the result of original
research work and is of sufficiently high standard to warrant its presentation to the
examination. I also certify that neither the thesis nor its part thereof has been previously
submitted by him for a degree of any university.
Date:
(Dr. V. VIJAYA LAKSHMI)
Chairperson
CERTIFICATE
This is to certify that the thesis entitled “DEVELOPMENT AND EVALUATION OF
INSTANT OMELETTE MIX WITH EGG AND WHEY POWDER.” submitted in partial
fulfillment of the requirements for the degree of “MASTER OF SCIENCE IN FOOD
TECHNOLOGY” of the Professor Jayashankar Telangana State Agricultural University,
Hyderabad is a record of the bonafide original research work carried out by Mr. K. V. V. S.
RAJANI KUMAR under our guidance and supervision.
No part of the thesis has been submitted by the student for any other degree or diploma.
The published part and all assistance received during the course of the investigations have been
duly acknowledged by the author of the thesis.
Thesis approved by the Student’s Advisory Committee
Chairperson :
Member :
Member :
Dr.V.Vijayalakshmi
Professor& Head,
Department of Foods and Nutrition,
Homescience, PJTSAU, Saifabad, Hyderabad.
___________________
Dr.S.Suchiritha Devi
Assistant Professor,
Department of Foods and Nutrition,
PG&RC,PJTSAU,
Rajendranagar, Hyderabad – 500 004.
___________________
Dr.N.Krishnaiah
Professor,
Department of veterinary public health
College of veterinary science
SPVNRTSU, Rajendranagar,
Hyderabad
___________________
Date of final viva-voce:
ACKNOWLEDGEMENTS
First, I want to thank God Almighty for the abundant blessing that has helped me in
each step of the progress towards successful completion of the project. At the very outset, I
submit the commodious and indefinite thanks to my family members, teachers and friends for
successful accomplishment of two years in this college and to present this diminutive piece of
work.
I am in dearth of words to express my sense of gratitude to my beloved parents
Sri.K.Narayana Rao and Smt. Samudraveni for giving me these wonderful life and my caring
sisters Uma and sirisha and who have always strived for my well being and their unforgettable
efforts in bringing me to these stage, without whom I could not have achieved all my success in
my life.
It gives me great pleasure to humbly place on record my profound sense of gratitude,
indebtedness and heartfelt thanks to my major advisor and chairperson of my advisory
committee,
Dr.V.Vijayalakshmi
Professor
and Head,
Department
of Foods
and
Nutrition,Home science, PJTSAU, Saifabad, Hyderabad.for her initiative, benevolence,
constant encouragement, warm affection, moral support, caring nature and ready help which
enabled me to overcome several stumbling blocks during the period of my investigation and
also in the preparation of this thesis. I will be always indebted for all the help provided by my
chairperson which cannot be valued in any terms and a great, heartfelt thanks to my
chairperson without her support and her motivation, I could not have completed my thesis and
come to this position.
I wish to express my esteem towards Dr.S.Suchiritha Devi and Dr.N. Krishnaiah Member of
Advisory Committee, for there sustained interest, caring nature, immense help, fruitful advice
and co-operation.
It gives me great pleasure to humbly express my profound gratitude and heartfelt
thanks to Dr. K. UmaMaheswari, Professor and Head, Department of Foods and Nutrition,
Post Graduate and Research Centre, Rajendranagar, Hyderabad for her cooperation and
kindness during my study. I express my sincere gratitude and thanks to my caring professors
Dr. T.V. Hymavathi, Dr. Aprana, Dr. Jessie Suneetha and Dr. Anila Kumari of Post
Graduate and Research Centre, Rajendranagar, Hyderabad.
I use this opportunity to sincerely thank my classmates Suneel,Vishnu, Eswari,
Swaroopa, Praveen, Sai, Ramana, Srinu, Anuja, for their cooperation and help during these
two years of study.
I felt elated to express my thanks to those who directly or indirectly helped me in
successful completion of thesis work.
I am also thankful to the University for providing opportunity for studying in the
esteem university.
DATE:
PLACE: HYDERABAD
K.V.V.S)
(RAJANIKUMAR
Chapter No.
Title
I
INTRODUCTION
II
REVIEW OF LITERATURE
III
MATERIALS AND METHODS
IV
RESULTS AND DISCUSSION
V
SUMMARY AND CONCLUSION
LITERATURE CITED
APPENDICES
LIST OF CONTENT
Page No.
LIST OF TABLES
S. No.
1
2
Table No.
3.1
4.1
Title
Composition of different instant omelette mixes
Different Composition of the instant omelette mix
4.2
Nutritional composition of instant omelette mixes
3
4
5
6
4.3
4.4
4.5
4.6
7
4.7
Mineral content of omelette mix
Physical properties of instant omelette mixes
Emulsification properties of instant omelette mix
Volume of instant omelette prepared from dry instant
omelette mixes.
Mean consumers score of instant omelette prepared
4.8
using instant omelette mix
Microbial analysis of the instant omelette mixes
8
Page No.
LIST OF ILLUSTRATIONS
S. No. Figure No.
1
3.1
2
4.1
3
4.2
4
4.3
Title
Flow diagram for Instant omelette mixes
Packed density of dry instant omelette mixes
Volume of instant omelette prepared from dry instant
omelette mixes
Mean consumer scores of omelette mixes
Page No.
LIST OF PLATES
S. No. Figure No.
Title
1
3.1
Pasteurized Spray dried hen whole egg powder
2
3.2
Spray dried whey powder
3
3.3
Egg powder 55% and whey powder 35% omlette mix
4
3.4
Egg powder 60% and whey powder 30% omlette mix
5
6
3.5
3.6
Egg powder 65% and whey powder 25% omlette mix
Egg powder 90% omlette mix
7
3.7
Microbial analysis of omlette mix
Page No.
LIST OF APPENDICES
S. No.
1
Appendix No.
A
Title
Consumer evaluation score card of omlette
prepared from instant omelette mixes
Page No.
LIST OF SYMBOLS AND ABBREVIATIONS
%
:
Percent
@
:
at the rate
<
:
Less than sign
>
:
More than sign
±
:
Plus- Minus symbol
µg
:
Microgram
µl
:
Micro liter
aw
:
Water activity
ANOVA
:
Analysis of Variance
AOAC
:
Association of Analytical Chemists
AOAC
:
Association of Official Analytical Chemists
AOX
:
Antioxidant Activity
BHA
:
Butylatedhydroxyanisole
BHT
:
Butylatedhydroxytoulene
CAE
:
Catechin equivalent
CD
:
Critical difference
Cv
:
Cultivar
CVD
:
Cardio Vascular Disease
DEW
:
Dried egg powder
DTT
:
Dithiothreitol
DPPH
:
1,1-diphenyl-2-picryl-hydrazyl
e.g.
:
for example, for instance
et al.
:
and other people
etc.
:
and so on; and other people/things
EWP
:
Egg white protein
EY
:
Egg Yolk
FAO
:
Food and Agriculture Organization
Fig
:
Figure
g
:
Gram
g/l
:
Gram per liter
GAE
:
Gallic acid equivalent
h
:
Hour
HEW
:
Hen egg white powder
i.e
:
Means
kg
:
Kilogram
l
:
Liter
mmol/L
:
Millimole per liter
mg
:
Milligram
min
:
Minute(s)
ml
:
Milliliter(s)
N
:
Normality
NADH
:
Nicotinamide Adenine Dinucleotide
NaOH
:
Sodium hydroxide
NBT
:
Nitro blue tetrazolium
NDF
:
Neutral detergent fiber
NEM
:
N-ethylamine
No.
:
Number
NS
:
Non significant
ºC
:
Degree Celsius
OD
:
Optical density
ORAC
:
Oxygen radical absorbance capacity
PE
:
Pyrocatechol equivalent
PG
:
Propyl gallate
pH
:
Log of H+ ion concentration
PI
:
Iso Potential point
PMS
:
Phenazinemethosulphate
ppm
:
Parts per million
PPO
:
Poly Phenol Oxidase
PUFA
:
Poly unsaturated fatty acid
QE
:
Quercetin equivalents
RE
:
Rutin equivalent
RP
:
Reducing power activity
rpm
:
Revolutions per minute
RSA
:
Radical Scavenging Activity
SD
:
Standard deviation
sec
:
Second(s)
SEd
:
Standard error deviation
SOA
:
Super oxide anion radical activity
SOD
:
Super Oxide Dismutase
TA
:
Titrable Acidity
Td
:
Denature temperature
TBA
:
Thiobarbituric acid
TBARS
:
Thiobarbituric acid Reactive Substance
TBHQ
:
Tert-butylhydroquinone
TCA
:
Trichloro acetic acid
TF
:
Total flavonoid content
TP
:
Total phenolic content
TSS
:
Total Soluble Solids
UV
:
Ultra violet
viz.
:
Namely
WHO
:
World Health Organization
WP
:
Whey Protien
wt
:
Weight
α
:
Alfa
β
:
Bet
INTRODUCTION
. Chapter I
INTRODUCTION
Egg and egg powders are widely used as ingredients in the food industry
because of their nutritional, functional and sensory qualities. Nutritionally, eggs are of
particular interest because of their high-quality proteins, lipids, vitamins and minerals
(Walker et al., 2012).
Egg constitutes a highly complex food system both in terms of composition and
physico chemical structure. The main constituents of egg are lipids and proteins with
exceptionally high biological value and remarkable functional properties. Whole egg or
its fractions i.e, the yolk and white, are extensively used as functional ingredients in
foods such as salad dressings, cakes, omelette, sauces, pie fillings, confectionery, meat
products, etc. They play an important role in product preparation as well as in
improving the physico-chemical stability (Kiosseoglou, 1989; Mine, 2002; Powrie and
Nakai, 1984). One key functional property of egg proteins is that it determines the
rheological and textural characteristics of foods such as heat-set creams, omelette,
cakes, etc., is their ability to coagulate and form a gel network exhibiting a solid-like
behaviour (Kiosseoglou, 2003a, b; Paraskevopoulou et al., 2000). Both white and yolk
tend to form gel structures upon heating. The egg white fraction, however, produces
stronger and more resilient gel network compared to yolk, when heated at relatively
high temperatures i.e. above 85°C at which denaturation of ovalbumin takes place
(Woodward, 1990). The yolk, on the other hand, is well known for its remarkable
emulsifying ability, attributed to the presence of lipoproteins. More specifically, the
lipoprotein molecules of lipovitellenins, the main constituents of the yolk micelle,
exhibit a high surface penetrating power, due to their structural flexibility, that enables
the molecules to rapidly adsorb and rearrange in the oil–water interface of the emulsion
droplets (Aluko et al., 1998; Kiosseoglou and Sherman, 1983; Martinet et al., 2002).
On the other hand, globular and less flexible proteins, such as those of egg white or the
yolk plasma livetins, adsorb less effectively at the droplet surfaces in the presence of
yolk lipoproteins and are competitively excluded from the droplet surfaces (Shenton,
1979). Therefore in food emulsion system containing whole egg, it is expected that the
absorbed membrane around the droplets will be built up mainly by the yolk lipoproteins
while the continuous phase of the emulsion is expected to be dominated by the nonadsorbing egg white and the yolk plasma globular proteins. When such a system is
heat-treated an emulsion gel structure made up of oil droplets embedded in a gel
structure results. Depending on parameters such as droplet size and droplet surface
network interactions, the droplets may act as fillers and modify the mechanical and
textural properties in the resulting gel. Examples of products where such a situation
may be encountered are foods such as creams, cake batters and pie-fillings.
Furthermore, a better understanding of the role of yolk-stabilized emulsion gels may aid
in the development of novel gel structures where the emulsifying potential of yolk
lipoproteins with the gel forming ability of egg albumen are combined (Kalkani et al.,
2007).
Egg yolk is particularly recommended for its emulsifying and thickening
properties in mayonnaise, salad dressings, ice creams and bakery products, in addition
to its colouring property. Egg products are often employed as functional ingredients in
the form of powders that offer numerous advantages: reduction of transportation and
storage costs, protection against microbial growth and easier dosage during industrial
manufacture.
The application of thermal processes to eggs is widely used by the egg industry
to produce more convenient egg products. Traditionally, liquid eggs are pasteurised to
ensure food safety by reducing the quantity of microorganisms responsible for illness
(Monfort et al., 2012). Recently, there has been an increased demand for dried egg
products in the food industry for manufacture of ready-to-use products and handling
considerations (Cecile et al., 2013). In the food industry, dried egg products are being
used extensively as an ideal ingredient in preparation of bakery foods, bakery mixes,
mayonnaise and salad dressings, confections, ice cream, pasta and many others
convenience foods (Bergquist, 1995).There are not only excellent nutritional and
functional properties of dried egg products, but also several advantages compared to the
liquid egg products i.e., (1) transport and storage of dried egg products is easier, less
costly and requires less space; (2) dried egg products are less susceptible to microbial
growth because of low moisture content; and (3) the uniformity and easy dosage of
dried egg products (Qinchun et al., 2012). Spray-drying is one of the techniques
frequently used to obtain powdered eggs from liquid eggs (Ayadi et al., 2008; Guardiola
et al., 1995). The industrial treatment of whole egg and egg yolk differs from that used
for egg white. Whole egg and egg yolk require pasteurization before drying, which is
not necessary for egg white because this operation is done in the dry state (Galet et al.,
2010).
The overall conditions encountered during the thermal treatments are susceptible
to modify the functional properties of egg products, mostly by decreasing the protein
solubility, on a way that may be damaging or beneficial, conferring new functionalities
to the powders (Galet et al., 2010).
During spray-drying, the temperature of the
droplets remain lower than the temperature of the outlet air, i.e. under 90–100°C and
drying occurs within a few seconds limiting thermal denaturation, particularly in the
three-stage drying process. This process is equipped with two fluid beds, an integrated
one at the bottom of the drying chamber and an external with agglomeration, additional
drying and cooling functions (Schuck et al., 2009).
The drying parameters are
interdependent: the outlet air temperature can be adjusted to the powder characteristics,
by regulating the inlet air temperature and the concentration and air flow rates. Usual
moisture content and water activity of egg yolk powder are around 3–4% and 0.2–0.3
respectively. The storage conditions, time and temperature, over periods corresponding
to the shelf life of powders also have to be considered (Rancou et al., 2015).
Usually dairy industries treat whey as an industrial waste, therefore, studies for
utilization of whey began way back in the 1920’s and since then they have further
intensified, as the non-rational use of whey is an economical and even antisocial
practice, not only because of its characteristic nature as a pollutant, but also due to the
global food shortage (Silva et al., 2015).
Whey is the liquid resulting from the
coagulation of milk and is generated during cheese manufacture. There are, basically,
two types of whey, which are: sweet whey with a pH of at least 5.6,which originates
from rennet-coagulated cheese production such as cheddar; and acidwhey, with a pH no
higher than 5.1,which comes from the manufacture of acid-coagulated cheeses such as
cottage cheese. Lactose and soluble proteins are the major components of whey solids.
Typically whey contains about 4.6% lactose, 0.8% protein and 0.6% fat (Walstra et al.,
2006). Many studies have been focused on the recovery of whey protein for use in the
human diet due to its bioactive properties. On the other hand, lactose may be used in
the pharmaceutical industry as a supplement in infant formulas, or bakery products to
enhance the colour or taste of food (Schaafsma, 2008). Moreover, lactose may also
serve as a source for renewable energy production, by means of hydrolysis and
fermentation of its monomers (Hosseini et al., 2003; Sansonetti et al., 2009).
Foams have important applications in a variety of food products. In the food
industry and culinary art, egg white protein (EWP) has been traditionally used as a
foaming agent because of its apparently unique foaming characteristics (Xin and Allen,
2011). Whey proteins have a comparable foaming capacity (overrun or air phase
fraction) and a potential to replace EWP as a foaming agent.
Consumer today wants a convenient mix which is simple to prepare, convenient,
healthy, containing natural foods where egg is a viable option for all these
characteristics. Eggs have many functional properties including emulsifying, aerating
and thermal setting characteristics, which account for its wide use in foods. The
characteristic of thermal setting is especially important. The functions of emulsification
and aeration are not unique to eggs but the combination of all three functions in a single
natural food is unique. Limited information is available on different egg products, such
as egg coated potato (Muller, 1994), premixed flavoured egg product (Wu et al., 1995),
egg flakes containing monosodium glutamate and onion/garlic extracts (Lee et al.,
1998), egg white chips containing stabilizers and flavouring agents (Yang et al., 2000),
formulated fried egg (Merkle et al., 2003) etc. Eggs in the shell are convenient to
household uses but not for industrial uses. Shell eggs lose their freshness quickly, even
when refrigerated and eventually spoil.
Therefore, efforts were made to design a research project for preparation of
instant omelet mix utilizing egg and whey powder with a combination of a whey
powder and a heat-settable egg powder blended in right proportions to make a dry
nutritionally enriched, instantly dispersible, fully functional, high protein, tasty
(additives of spices) food product i.e., omelette. Simultaneously, efforts have been
made to study the physicochemical, nutritional and sensory properties of the omelette.
Therefore the study was designed with the following objectives
OBJECTIVES
1. To develop an instant omelette mix (Indian style) as a nutritious breakfast item
by using spray dried whole egg powder and whey powder.
2. To standardize the process and formulation for preparation of Instant omelette
mix.
3. To conduct consumer’s acceptability studies.
4.
5.
REVIEW OF
LITERATURE
Chapter II
REVIEW OF LITERATURE
The present study entitled “Development and evaluation of instant omelette mix
with egg and whey powders” was conducted in the Department of Foods and Nutrition,
Post Graduate & Research Center, Professor Jayashankar Telangana State Agricultural
University, Rajendranagar, Hyderabad during the year 2015.
2.1 Egg powder
2.1.1 Physico-chemical properties of egg powder
Kralik G et al.(1990) Eggs are very important for feeding people as they have high
nutritive value and are suitable for processing of the edible part of a hen egg contains
72.5-75.0 g of water, 12.5-13.3 g of protein, 10.7-1 1.6 g of fat, 0.7 g of carbohydrates
and 1.0-1.1 g of mineral substance. The human body also makes good use of the
nutritive value of eggs : proteins are utilized at 97%, fats 95%, carbohydrates 98% and
minerals 76%. The content of essential amino acids in eggs is also very important,
specially leucine, isoleucine, lysine, arginine, valine and phenylalanine. Eggs are also
rich in vitamins -specially A, K and B complex - and also in different macro and micro
minerals
Rannou et al. (2015) evaluated the effect of the processing and storage
conditions on the physical and functional properties of egg yolk (EY) powders. The
spray-drying temperature (160°C vs. 180°C), storage temperature (15°C vs. 30°C) and
time (1, 2, 4 and 8 months) and n-3 enrichment through hen diet were investigated. The
spray drying temperature and storage conditions modified the water content, water
activity and the particle size distribution of egg yolk powders. Flowability of the
powders and the emulsifying properties were not significantly affected from an
industrial point of view. On the other hand, viscosity increased with the spray-drying
temperature as well as the temperature and time of storage in rehydrated powders.
Powders prepared with n-3 enriched egg yolks exhibited lower melting peaks
temperatures, a marked yellow colour and higher fluidity of the solutions, but the
overall properties remained unchanged. This study clearly attests the possibility of an
industrial production of n-3 enriched egg yolk powders.
Cecile et al. (2013) determined whether compositional or processing parameters
have an influence on the odour quality of egg powders. The parameters tested were:
whole egg vs. egg yolk, poly unsaturated fatty acid (PUFA) enrichment, spray-drying
temperature (160°C vs. 180 °C), production scale (industrial vs.pilot plant), storage
temperature (15°C vs. 30°C) and time (1, 2, 4 and 8 months). The quality of egg
powders was evaluated by sensory analysis using free sorting and by gas
chromatography coupled to mass spectrometry and olfactometry. PUFA enrichment
and spray-drying temperature do not affect the odour of egg yolk powders. There were
significant differences found between the odour of whole-egg and egg-yolk powders as
well as between powders produced on an industrial scale and a pilot plant. An increase
in the odour intensity of egg powders was observed during storage at 35°C temp, while
unpleasant odours were perceived when the egg powders were stored at 30°C.
Kumaravel et al. (2012) simplified the technique of production of dried egg
powder through vacuum drying.
The advantage of production of egg powder by
variation in its technology which can help for a better quality and cost efficient product
was tested. Eggs as a raw source were collected from the local poultry farm and various
processes for production of egg powder were carried out. High risk factors like, reduced
glucose in the dehydrated product gets eliminated through vacuum drying technology.
The increase of carbohydrate in the egg powder produced through vacuum technology
had a visible proof of increased shelf life which indirectly reduced the risk of
caramelization. Proteins in egg white like ovomucoid and ovalbumin which were
considered to be important for blocking digestive enzymes were also eliminated through
this technology.
Qinchun et al. (2012) explored the moisture-induced effects on food protein
hydrolysates and the resulting changes in the structure and texture of the food matrix as
well as the loss in functional properties of bioactive peptides during storage. The main
purpose of this study was to determine the influence of water activity (aw) on the
storage quality of a commercial spray-dried hydrolysed hen egg white powder (HEW).
During storage at 45°C for two months at different a ws (0.05–0.79), the selected physico
chemical properties of the HEW samples were analysed. The results showed that the
effect of aw on the colour change of HEW at 45°C for one month was similar to that of
HEW after four months at 23°C due to the presence of a small amount of glucose in
HEW. Several structural changes occurred at aws from 0.43 to 0.79 including
agglomeration, stickiness and collapse. Kinetic analysis showed a first-order hyperbolic
model fit for the change in the L value, the total colour difference (DE) and the
fluorescence intensity (FI). There was a high correlation between colour change and
fluorescence, as expected for the maillard reaction. After storage for one month the
reduction in the remaining free amino groups was about 5% at aw 0.50 and 6% at aw
0.79. It was concluded that during storage, the maillard reaction and/or its resulting
products could decrease the nutritional value and the quality of HEW.
Qinchun et al. (2012) studied physico-chemical properties of two hen egg white
powders (with and without hydrolysis) after short-term storage at 23°C.
It was
observed that the effect of moisture content on physico-chemical properties of
hydrolysed egg white powder (HEW) was more severe than those of dried egg white
powder (DEW). The denaturation temperature (Td) and the enthalpy change (DHd) of
ovalbumin in DEW followed an exponential model, and was similar in the Td of HEW.
The Gordon–Taylor equation modelled well with the glass transition temperatures (Tg)
of HEW and DEW. The Guggenheim–Anderson–de Boer (GAB) model fitted well to
the type II moisture sorption isotherm. At the critical moisture content (12.0%, on dry
basis), compared with DEW, the colour of HEW began to darken dramatically and its
hardness started to change significantly. These changes were closely related to the
inherent characteristics of the two products.
Joel et al. (2010) studied the effect of oven drying on the functional and
nutritional properties of whole egg and its components viz; emulsification capacity and
stability, foam capacity and stability, water and oil adsorption capacity,coagulation
temperatures, solubility and nutritional composition was studied using standard
methods. The results obtained showed that egg yolk powder had better emulsification
capacity (74%) and stability (72.4%) compared to whole egg (55 and 44.86%) and egg
white powder (17.77 and 14.70%). It was seen that the egg white powder had better
foam stability (78.3%) and emulsification capacity (97.5%) compared to whole egg
powder (59.28 and 40.0% respectively) and egg yolk powder (28.08 and 38.5%
respectively). The coagulation temperatures obtained for egg yolk, egg white and whole
egg were 66.5°C, 63°C, and 64°C, respectively. The highest solubility was recorded in
egg white (96%), followed by whole egg (92%) and egg yolk (88%) powders, while the
reverse was the case for the water and oil absorption properties which gave values of
1.6, 0.5, 1.8 and 2.6, 0.6, 0.5 g for the whole egg powder, egg yolk powder and egg
white powder, respectively. The total solids were significant by more in whole egg
powder (93.26%), egg yolk powder (96.12%) and egg white powder (95.88%). The
results also showed that the nutrient composition of the egg and its components were
minimally affected by oven drying.
Kuropatwa et al. (2009) studied the impact of protein–protein interactions on
foaming properties of mixtures consisting of egg white proteins (EWP) and whey
proteins (WP) with total protein content of 60 g/L at pH 5, 7 and 9. The ratio between
EWP and WP in the mixtures was varied between 67:33, 50:50 and 33:67 (in %; w/w).
The ionic strength was adjusted to that of milk (I ¼ 176 mM). The foamability of the
protein was characterized by the foam capacity, stability and firmness. In addition, the
hydrophobicity in the protein solutions was assessed as a measure for the physical
behaviour and ability of proteins to adsorb at the air–water interface. The individual
egg white proteins and whey proteins each showed the best foaming properties at pH 5
and pH 9, respectively. At pH 9 a synergism was observed in the emulsion capacity and
stability of the foams from EWP/WP mixtures. This effect appears to be caused by the
electrostatic interactions between egg white and whey proteins which occur in the bulk
solution after the pH adjustment prior to the foaming. In contrast, at pH 5 no positive
influences of foaming the components in a mixture as well as no indication of inter
molecular interactions were found. At pH value near the PI (Iso potential point) of
ovalbumin the protein interactions occur when the proteins have adsorbed at the air–
water interface. The protein systems foamed at pH 7 showed intermediate foamability
compared to the values obtained at alkaline and acidic pH.
Kalkani et al. (2007) studied the effect of incorporation of emulsified oil with
yolk on the strength of gel network systems, produced by heating of egg yolk or egg
white dispersions, was investigated. The yolk gels exhibited a decrease in their
mechanical strength as a result of oil incorporation. The white-based gels, on the other
hand, showed a higher strength, following incorporation of oil droplets, the result
depending on the droplet size but more on oil levels. The interaction between the
globular proteins of egg white and the lipoprotein-covered oil droplet surfaces was
established by applying SDS-PAGE electrophoresis. The results were discussed in
terms of the differences in structure of the yolk and the white proteins that may affect
the way they denature and interact following heating.
Vassilis and Adamantini, (2005) studied to establish the role of disulfide
covalent bonds and hydrophobic interactions. The behaviour of hen’s egg yolk or its
plasma and granules fractions, upon heating at 90.8°C for 30 min in the presence of D,
L-dithiothreitol
(DTT),N-ethylmaleimide
(NEM),
was
between
yolk
protein
constituents in the formation of gel network structure. The application of uniaxial
compression test to gel samples indicated that the yolk and its plasma fraction exhibit a
similar behaviour, regarding the involvement of disulfide bonds between their protein
constituents in gel structure development, as both samples produced weak gels in the
presence of DTT and NEM. On the otherhand fracture properties of granules in a
fraction gel, were not markedly affected by disulfide bond-splitting or addition of
sulfhydryl group-blocking reagent. Hydrophobic interactions appeared to influence the
gel structure development by yolk or plasma while disulfide linkages formed between
interacting protein molecules, either through sulfhydryl–disulfide interchanges or as a
result of sulfhydryl groups’ oxidation, appear to play a complementary role. These
findings were supported by turbidity measurements of heated dispersions of yolk and its
fractions and by SDS-PAGE (sodium dodecyl sulphate) analysis.
2.1.2Products preparation and evaluation of egg based products
Muthia et al. (2012) evaluated the effects of using tapioca and sago flours
with or without egg white powder (EWP) on the physico-chemical and sensory
properties of duck sausages. There was a significant increase (P<0.05) in the protein
content, folding test, cooking yield, water holding capacity (WHC), lightness, moisture
retention and fat retention in duck sausages prepared using flours combined with EWP.
However, the ash and carbohydrate contents of duck sausages prepared using flours and
EWP decrease significantly compared to their counterparts without EWP. There was no
significant difference (P>0.05) in hardness and cohesiveness among all the samples
examined but significant differences (P<0.05) occurred in springiness, chewiness and
gumminess. Overall acceptability was higher for duck sausages prepared using sago
flour and EWP compared to duck sausages prepared with tapioca flour and EWP.
Tan et al. (2012) compared the degree of denaturation and functional
properties (emulsifying, foaming, and gelling properties) of egg white obtained from
pasteurized eggs with those of unpasteurized eggs (EWUP). Data from differential
scanning calorimeter showed that the EWP (ovotransferin, lysozyme and ovalbumin)
denatured at lower temperatures and required lower denaturation enthalpies than
EWUP, indicating a partial loss of protein structure during the pasteurization process in
the pasteurized eggs. The emulsion and foam stability formed from EWP were
significantly (P <0.05) lower than those of EWUP, however the EWP formed stronger
gels than EWUP. To assess suitability of EWP as a cake ingredient, an gel food cake
was prepared using both egg whites. As compared to EWUP-cake, EWP-cake was
significantly (P < 0.05) lower in volume, cohesiveness and springiness values, but
significantly (P < 0.05) higher in hardness, gumminess and chewiness. The sensory
panel lists gave significantly (P <0.05) higher scores for angel food cake prepared with
EWUP. The differences in functional properties of egg white proteins and the quality of
cakes were mainly due to the higher levels of denaturation attained by EWP as a result
of the pasteurization process.
Deepthi et al. (2011) prepared a shelf stable, low fat (< 1%) paneer like product
from egg albumen. This texturized egg albumen product, labelled as egg albumen
paneer (EAP), was developed by texturizing liquid egg albumen by incorporating
optimized quantities of wheat flour and rice flour. Dehydrated EAP was packed in
metalized polyester pouches, stored at ambient temperature (27±2°C) for 6 months and
sampled periodically for quality evaluation. The protein content of dehydrated EAP
was 21.08±1.35%. The shelf stability of the product was achieved by keeping the
moisture content (9.68±1.02%) and water activity (0.54±0.02) low.
A significant
increase (p≤0.05) in the volume of EAP was observed on rehydration. The rehydration
capacity was 84.10±5.35% for the product. During first three months of storage, there
was a marked change (p≤0.05) in rehydration ratio; however, further storage did not
affect it. Storage period did not significantly (p≥0.05) affect the lipid oxidation
parameters, physical properties, textural profile and colour traits of the product. The
standard plate counts and yeast and mould counts fluctuated within the range of
0.90±0.05 - 3.25±0.05 and 0.84±0.04 - 2.52±0.33 log cfu/g, respectively during storage.
Staphylococcus aureus, E. coli, Salmonella and Shigella, however, were not detected in
any sample throughout the storage period. Sensory evaluation revealed that rehydrated
paneer, the product had excellent texture, and was very close to fresh one (before
drying) after storage for six months. An average sensory score were 7.5 to 8.7 on 9
point hedonic scale indicated that the product was liked very much.
Jones, (2007) undertook the study to determine the changes in functional
characteristics and quality factors of commercial shell eggs during 10 wk storage at
4°C. Commercially processed eggs were collected for three consecutive weeks from an
in-line facility. An analysis was conducted the day after collection of 0wk and each
subsequent week. Total solids for the albumen, yolk and whole egg were
determined.Functional properties were examined via preparation of angel food cakes,
mayonnaise and sponge cakes. Color was also measured for both raw yolks and
prepared mayonnaise. Albumen solids were fairly consistent during storage (12.2 to
12.6%). Whole egg solids remained constant. Yolk solids decreased throughout storage
(48.2 to 43.2%). Angel food cake volume decreased as the egg aged. Sponge cake
volumes were inconsistent throughout testing with no clear apparent trends. Mayonnaise
was tested immediately after preparation (fresh) and incubation at 50°C for 7 days. In
both cases, the average force required to compress the mayonnaise decreased with
increase in the storage period. Differences were detected for changes in color values
(L*, a* and b*) for yolks over time, but these changes were not of a magnitude to be
seen by the human eye.
Most of the measured parameters exhibited significant
interactions for replicate and egg storage. These interactions show that variability exists
within the testing methods and more objective methods for determining shell egg
functionality need to be developed.
Sauter and Petersen, (1979) evaluated pasteurized frozen whole egg (PWE) for
use as the principal ingredient in preparation of omelette. Three types of omelette were
used in the evaluation: plain, beaten ,whole egg; puffy, normally prepared with yolk and
white whipped separately; and 10-min omelettes prepared similarly to puffy omelettes
with added 40g of flour. Sensory evaluation of omelettes made from PWE were
comprised with reference omelets made from fresh eggs for acceptability, color, flavor,
moistness and tenderness.
2.2 Whey powder
2.2.1 Physico-chemical properties of whey powder
Gholamreza, (2014) investigated the performance of a spray dryer for the
preparation of whey powder. Its main objective was to categorize unknown samples
using analysis of discrimination function between the operating variables and powder
properties in two or more naturally occurring groups. In this work, spray drying was
performed on a pilot-scale concurrent spray dryer. The amount of solid content, inlet,
and outlet air temperature was chosen as independent variables. The titratable acidity,
pH, EC, TDS, analytical elements, particle size, diameter, ingredients, and morphology
were the response variables that quantified the powder quality. Results showed that pH
of whey powder with 15 % solid content was lower than the pH of whey powder with
30 % solid content. Furthermore, the pH of the whey dried at inlet (outlet) air
temperature of 180°C (106°C) was lower than the whey dried at 145°C (87 °C).
Substances with higher acidity had higher electrical conductivity (EC) as well. The
mean particle diameter of the powders produced by pilot plant spray dryer were in the
range of 11.26–18.23 lm. SEM picture showed that in pilot-plant spray dryer, therewere
a few shallow holes on the particle surfaces as well as a few particles.
Giyani et al. (2007) developed a simplified method to study rehydration which
was used on different dairy powders. The method involved dispersing powder in a
vessel equipped with stirrer and a turbidity sensor. The changes of turbidity occurring
during powder rehydration highlighted the rehydrating on stage and the influence of the
proteins on rehydration was clarified. Casein powders had a quick wetting time but
very slow dispersion, making the total rehydration process time-consuming. On the
other hand, whey powders were found to have poor wettability but demonstrated
immediate dispersion after wetting. Mixing casein (80%) and whey (20%) before spray
drying greatly improved rehydration time compared to casein powder; where as mixing
whey powder with casein powder in the same ratio after spray drying caused a dramatic
deterioration in the rehydration properties. Moreover, agglomeration was found to slow
down the rehydration time of casein powder. These opposite effects were related to the
rate-controlling stage (i.e., wetting stage for whey protein and dispersion stage for
casein).
2.2.2 Product preparation and evaluation of Whey Powder based products
Alfaifi and Stathopoulos. (2010) evaluated the changes in the gelato ice cream
properties at different levels of sweet whey protein concentrate (WPC) substitutions of
egg yolk. Samples were made with two levels of egg yolk (4.5 and 9%). For each level
one control sample with no WPC addition and four levels of WPC substitutions (20, 50,
80 and 100%) were made. Three replications of each treatment were performed.
Samples were evaluated for mix viscosity, overrun and texture. Determinations of these
parameters were made after four weeks of storage. Results showed that samples
containing 9% egg yolk were more viscous than those containing 4.5% egg yolk. More
over, increasing WPC substitution led to increased over run (%), number of aircells
formation and texture characteristics of the Gelato samples. On the whole significant
(P<0.05) effect of fat content was observed and reported in all physical properties
measured.
2.3 Physico-chemical properties of blend of egg and whey based products
Tan et al. (2015) applied ultra sound treatment on whey protein concentrate
suspension prior to foaming and being mixed into batter for eggless cake. The
improvement of batter and baked cake made using ultrasound treated whey protein were
measured in terms of aeration, rheological and textural properties.
Baked cakes
formulated with untreated whey protein suspension at varying concentrations between
10 and 20 % were compared with ultrasound treated whey protein upto 25 min at 60 %
amplitude. Visualized images of aerated cake products using x-ray tomography
technique supported the findings of improved batter in terms of decrease in density by
5 % and viscosity, consistency index, storage modulus, and loss modulus increase by
31, 57, 33, and 21 %, respectively. For baked cakes, increase in volume was 18 %, and
density, hardness, and chewiness decrease was 18, 65 and 64 %, respectively, when
compared to those made using untreated whey protein. Image analysis presented a
higher number of smaller gas cells in the aerated baked cakes structure using ultrasound
treated whey protein.
Alessandra et al. (2014) studied the effects of adding egg albumen or whey
proteins to pasta made from parboiled rice flour (PR) were investigated. Pasta quality
was evaluated in terms of colour content and cooking properties (water absorption,
cooking loss, and consistency at the optimal cooking time). The surface heterogeneity
of the cooked and uncooked materials was studied and some starch properties (pasting
properties and starch susceptibility to α-amylase hydrolysis) were assessed, along with
the features of the protein network as determined by conditional solubility studies and
with ultrastructural features of the cooked products. Egg albumen improved pasta
appearance and gave a product with low cooking loss, firmer, and nutritionally more
valuable than the other ones. In albumen-enriched pasta, small starch granules appear
homogeneously surrounded by a protein network. In the uncooked product, the protein
network is stabilized mostly by hydrophobic interactions, but additional disulfide inter-
protein bonds form upon cooking. Thus, addition of 15 % liquid albumen to PR results
in significant improvement of the textural and structural features of rice-based glutenfree pasta.
Xin and Allen, (2011) determined the physical models, based on micro-scale
(bubbles) and nano-scale (interface) properties and stated that they can be used to
explain the macroscopic foaming properties of egg white protein (EWP) and whey
protein isolate (WPI). Foam properties were altered by adding different amounts of
sucrose (4.27-63.6 g/100 mL) and microstructures were observed using confocal laser
scanning microscopy. Bubbles were quantitatively measured using image analysis.
Addition of sucrose decreased the initial bubble size, corresponding to higher foam
stability and lower air phase fraction. EWP foams were composed of smaller bubbles
and lower air phase fractions than WPI foams. Increased sucrose concentration caused
a decreased liquid drainage rate due to a higher continuous phase viscosity and smaller
bubble sizes. WPI foams had faster rates for liquid drainage and bubble coarsening than
EWP foams. The differences were attributed to faster bubble disproportion in WPI
foams, caused by lower interfacial elasticity and lower liquid phase fractions. The
experimentally fitted parameters for foam yield stress did not follow universal trends
and were protein type dependent. EWP foams had higher yield stress than WPI foams
due to smaller bubble sizes and higher interfacial elasticity. The yield stress of WPI
foams increased slightly with addition of sucrose and cannot be accounted based solely
on model parameters. It appears that changes in stability of EWP and WPI foams can
be explained based on physical models while protein-specific effects regarding foam
yield stress remain unaccounted.
Xin and Allen, (2010) studied the effects of sucrose on the physical properties of
foams (foam overrun and drainage ½ life), air/water interfaces (interfacial dilational
elastic modulus and interfacial pressure) and angel food cakes (cake volume and cake
structure) of egg white protein (EWP) and whey protein isolate (WPI) was investigated
for solutions containing 10% (w/v) protein. Increasing sucrose concentration (0–63.6
g/100 mL) gradually increased viscosity of solution and decreased the foam over run.
Two negative linear relationships were established between foam over run and solution
viscosity on a log–log scale for EWP and WPI respectively; while the foam overrun of
EWP decreased at a faster rate than WPI with increasing viscosity of the solution
(altered by sucrose). Addition of sucrose enhanced the interfacial dilational elastic
modulus (E′) of EWP but reduced E′ of WPI, possibly due to different interfacial
pressures. The ½ life of foam drainage was proportionally correlated to the bulk phase
viscosity and the interfacial elasticity regardless of protein type, suggesting that the
foam destabilization changes can be slowed by a viscous continuous phase and elastic
interfaces. Incorporation of sucrose altered the volume of angel food cakes prepared
from WPI foams but showed no improvement on the coarse structure. In conclusion,
sucrose can modify bulk phase viscosity and interfacial rheology and therefore improve
the stability of wet foams.
However, the poor stability of whey proteins in the
conversion from a wet to a dry foam (angel food cake) cannot be changed with addition
of sucrose.
Kuropatwa et al. (2009) studied the impact of protein–protein interactions on
foaming properties of mixtures consisting of egg white proteins (EWP) and whey
proteins (WP) with total protein content of 60 g/L was examined at pH 5, 7 and 9. The
ratio between EWP and WP in the mixtures was varied between 67:33, 50:50 and 33:67
(in %; w/w). The ionic strength was adjusted to that of milk (I = 176 mM). The
foamability of the protein products was characterized by the foam capacity, stability and
firmness. In addition, the hydrophobicity in the protein solutions was assessed as a
measure for the physical behaviour and ability of proteins to adsorb at the air–water
interface. The individual egg white proteins and whey proteins each showed the best
foaming properties at pH 5 and pH 9, respectively. At pH 9 a synergism was observed
in the capacity and stability of the foams from EWP/WP-mixtures. This effect appears
to be caused by the electrostatic interactions between egg white and whey proteins
which occur in the bulk solution after the pH adjustment prior to the foaming. In
contrast, at pH 5 no positive influence of foaming the components in a mixture as well
as no indication of intermolecular interactions was found. At pH value near the PI(Iso
Potential Point) of ovalbumin the protein interactions occur when the proteins have
adsorbed at the air–water interface. The protein systems foamed at pH 7 showed
intermediate foam ability compared to the values obtained at alkaline and acidic pH.
Jaritha and Kulkarni, (2010) studied the rusks prepared by incorporation of
concentrated whey by replacing water and reported that it not only contributes to the
nutritional attributes but also to the economy of operation of dairy plants by reducing
the cost of effluent treatment.
Chatterjee et al. (2009) narrated the antihypertensive nature of whey Protein
hydrolysate and reported that the bland neutral flavor of whey protein allows it to be
added to a wide variety of food beverages which helps in increasing protein content
without affecting taste.
Jisha et al. (2009) conveyed the textural and rheological properties of whey
protein concentrate fortified baked products from cassava based composite flours
reported that the use of melted cassava based composite mixes and fortification with
WPC could yield good quality eggless muffins and biscuits which could be consumed
by people having egg allergy and also by vegetarians.
Jooyandeh and Minhas, (2009) developed the effect of addition of fermented
whey protein concentrate on cheese yielded and fat and protein recoveries of cheese and
reported that with the incorporation of FWCP upto 15% in the milk, from which good
quality of cheese was obtained with higher yield and nutritional quality.
Khillari et al. (2007) evaluated the quality of low fat ice cream made with
incorporation of whey protein concentrate and shows that the protein content of low fat
ice cream increased with increased fat substitution.
Vani and Jayaprakasha, (2004) formulated the formulation of Instant gulab
jamun mix from the admixture of spray dried skim milk powder and whey protein
concentrate and showed that incorporation of WPC in the given formulation is possible
thereby extending the nutritional and functional properties of whey proteins by
retrieving the whey solids and thus overcoming the problems of whey disposal.
Harold et al. (2004) studied the factors affecting cross-linking of whey protein
isolate (WPI) using both soluble and immobilized T Gase and the rheological properties
of the modified proteins were characterized. These results suggest that a process could
be developed to produce heat stable whey proteins for various food applications.
MATERIALS AND
METHODS
Chapter III
MATERIAL AND METHODS
The present study entitled “Development and evaluation of instant omelette mix with
egg and whey powders” was conducted in the Department of Foods and Nutrition, Post
Graduate & Research Center, Professor Jayashankar Telangana State Agricultural University,
Rajendranagar during the year 2015.
This chapter includes detailed description of experimental procedure of the study under
the following heads.
3.1) Procurement of raw materials.
3.2) Product development.
3.3) Physico-chemical properties of instant omelette mix.
3.4) Proximate analysis in instant omelette mix.
3.5) Consumer evaluation of the developed product.
3.6) Microbial analysis
3.7) Statistical analysis
3.1. Procurement of raw materials
3.1.1. Egg powder
Pasteurized Spray dried hen whole egg powder was procured from Venkateshwara Hatcheries
Pvt limited, Hyderabad, India
Commercially procured egg powder preparation :
Eggs were obtained from hens fed with standard diet. A batch of 100 eggs (50-55g
each) of 3 days old, kept under room temperature (27 ± 2°C) were selected for the study. The
eggs were candled to confirm freshness and were cleaned by dusting, washing and allowed to
dry. They were carefully de shelled to obtain whole egg liquid. After industrial pasteurization
at 65°C for 5 min, spray-drying was done on a three-stage pilot plant of the Gea-Niro society
Saint-Quentin-en-Yvelines,France) at Bionov (Rennes,France) whose evaporation capacity is
80 kg h-1. The atomizer was equipped with a pressure nozzle (0.73mm diameter orifice)
providing a 60° spray angle. The spray-drying parameters were determined according to the
desorption method of Schuck et al. (2009). Dry air flow rate and nozzle pressure were of 2570
± 50 kg h-1 and 14 MPa respectively; the temperature of the integrated bed was 65 ± 1°C. The
inlet and outlet air temperatures were maintained at 160°C and 62°C respectively. The inlet
flow rate was maintained constant in order to avoid any modification of the particle size
distribution due to the conditions of spray-drying, with the disadvantage of increasing the
outlet temperature. Immediately after drying, powders were packed in polyethylene bags, and
put into kraft bags.
Plate no 3.1. Pasteurized Spray dried hen whole egg powder
3.1.2. Whey powder:
Whey powder was procured from M/S Paras Dairy Ltd, Hyderabad, India
Commercially procured whey powder preparation :
Whey with solid content (15, 30 and 40 %) was provided from a local supplier, stirred
and filtered for 30 min. It was dried in a pilot-plant spray dryer, which had a diameter of 1.42
m, cylindrical section height of 3.9 m and cone section height of
1 m.The air temperature
and relative humidity were about 25–30°C and 30–40 %, respectively. Whey feed (in 25–
30°C) was pumped into the nozzle at the rate of 180 ml/min and 40 bar pressure. Then,
atomization was performed by the twin-fluid nozzle, using compressed air at 1.5 bar. The
atomizing gas was fed from an in-house supply. Two inlet air temperatures (Ti) of 180°C and
145°C were used. The outlet air temperature (To) was monitored, continuously. Inlet and outlet
air temperatures were read and manually logged directly from the digital displays on the
dryer’s control panel. After drying, powder samples were transferred into sealed bottles, to be
maintained for the analysis step.
Plate no.3.2. Spray dried whey powder
3.1.3. Salt All the other ingredients like Iodized salt, chilli powder, curry leaf powder, onion
powder and edible vegetable oil were procured from the local market.
3.2. Product development
3.2.1. Preparation of Omelette mix
Instant dry omelette mixes were obtained by blending different proportions of commercial
powders, salt, chili powder, curry leaf powder, onion powder and ant caking agent using a hand
blender. One kg of blends was prepared according to composition shown in Table 3.1.
Table 3.1: Composition of different instant omelette mixes (g%)
Ingredients
Control
A
B
C
Egg Powder
90
55
60
65
Whey Powder
-
35
30
25
Salt
3.5
3.5
3.5
3.5
Chilli powder
2.5
2.5
2.5
2.5
Curry leaf powder
1
1
1
1
Onion powder
2
2
2
2
1%
1%
1%
1%
Anticaking agent (Silicon Dioxide)
Plate no.3.3. Egg powder 55% and whey powder 35% omlette mix
Plate no.3.4. Egg powder 60% and whey powder 30% omlette mix
Plate no. 3.5. Egg powder 65% and whey powder 25% omlette mix
Plate no 3.6. Egg powder 90% omlette mix
Weighing of Whole egg powder
Addition of whey powder, Salt, Chili powder, Curry leaf and Onion powder
Blending in blender in 5 minutes
Filling in to Laminated pouches
Sealing
Storage
Fig. 3.1. Flow diagram for preparation of Instant omelette mixes
3.2.2. Preparation of omelette :
Measured 200ml of water was added to the different instant dry omlette mixes to make
a batter. The batter was mixed with a spatula for 1 minute. The uniformly mixed batter was
poured on a preheated griddle of a commercial pan cake maker that had been lightly sprayed
with edible vegetable oil. The omelette samples were cooked at 120°C for 2.5 min until the
upper surface bubbled. The omelette was then turned to cook on the other side, which browned
in another 2–3 min. The hot omelette were studied for sensory characteristics.
3.3. Physical properties of instant omelette mixes:
3.3.1. Density
The density was measured with a densitometer DMA 45 device (chempro, paar, graz,
austria) at 5°C and used to calculate the weight of a known volume of solution.
3.3.2. Titratable acidity
Titratable acidity was used to measure instant dry acidity of instant omelette mixes (Li
and Shahbazi, 2006). A sample of titratable hydrogen ions includes free insoluble H + ions and
their combination with acids and proteins. After storing, the acidity of instant dry omelette
mixes increased, which negatively influenced its flavor and acceptability. During storage, the
acidity increased where the flavor worsened, and the acceptability decreased. The titratable
acidity was determined by titration of a known amount of reconstituted instant dry omelette
mix with 0.1 N NaOH using phenolphthalein as the indicator. This method may be used for all
types of dried milk products.
According to this standard, 6g of instant dry omelette mix was dispersed and dissolved
in 100 ml of deionized water and stirred gently. Then, it was left for about 1 hr from this, 20 ml
of solution was poured into a 100 ml Erlenmeyer flask and 0.5 ml of phenolphthalein was
added and titrated with 0.1 N NaOH until a faint pink color persisted for 30 seconds which was
the end point .The titratable acidity was calculated using the following equation in which v is
volume of 0.1 ml NaOH N is the normality of 0.1 ml NaOH and V is the volume of the
omelette solution in ml.
3.3.3. Solubility of the powder – Haenni value
The Haenni value is an industrial indicator for the solubility of egg powders. The
method was adapted from Hawthorne, (1944). Six grams of instant dry omelette mix was
dissolved in 30 ml of 5% (w/w) sodium chloride solution and left aside. Exactly after 20 min,
the refractive index of the solution was read and the solubility, reported as Haenni value (hv),
was calculated according to equation given below.
HV = (ȠDegg- ȠDNaCl) ×1000
Where ȠDegg corresponds to the refractive index of the solution composed of egg
powder in 5% (w/w) NaCl solution and ȠDNaCl corresponds to the refractive index of 5% NaCl
solution.
3.3.4. Foaming property
Foaming property was determined by using the method described by Song et al. (2009)
with some modifications. Instant dry omelette mix samples were diluted to 1:1 (v/v) with
distilled water. A volume of 30 ml solution was placed into a 100 ml cylinder and whipped for
1 min with a homogenizer at 12,000 rpm at 25°C. Foam stability was expressed as the percent
liquid drainage in relation to initial liquid volume as a function of standing time for 30 min.
Foaming stability was calculated using the following equation:
3.3.5. Emulsification property
The emulsification property of the instant dry omelette mix was determined by the
method described by Pearce and Kinsella, (1978). The emulsion was prepared by transferring
1.0 ml of palm oil into 3.0 ml of 0.1% w/v instant dry omelette mix sample in 100 mM of
sodium phosphate buffer at pH 7.4. The solution was homogenized in an ultra centrifuge at
12,000 rpm for 1 min at 25°C. Liquots of the emulsion (100 μl) were taken from the bottom of
the test tube at 0, 1, 2, 3, 5, 10 and 20 min. Then it was serially diluted with 5mL of 0.1%
sodium dodecyl sulfate solution. The absorbance of the diluted emulsion was measured at 500
nm in spectrophotometer for determining emulsifying properties.
3.3.6. Volume measurement of omelette
Omelette volume was measured by using the procedure described by Akesowan, (2007).
The test omelette was weighed and placed inside a box of known volume, followed by the
addition of rape seeds, which were leveled across the top with a spatula. The displacement of
the seeds was measured in a graduated cylinder and used to express the volume of the omelette.
3.4. Proximate analysis in instant omelette mix.
3.4.1. Chemicals and glassware:
All chemicals used in the investigation were of analytical grade. Chemicals and
glassware were utilized from the laboratory of Post Graduate and Research Centre, PJTSAU,
Rajendranagar, Hyderabad.
3.4.1 Estimation of moisture (AOAC, 2000)
Moisture and water content are among the most important parameters measured in
food. The content of moisture is inversely related to the dry matter of a food item. Hence there
are direct economic effects on consumers and processors. More over, the moisture content in
food also influences its stability and quality.
10g of food material was placed in known weight of dry Petri dish with lid. Petri dishes
were transferred to hot air oven with a temperature of 100°C to 105ºC till a constant weight
was obtained. It was followed by cooling in desiccators for 15 min and the final weight of
sample was recorded.
Calculation:
Moisture % =
x 100
3.4.2. Protein estimation (AOAC, 1990)
Principle:
The nitrogen in protein or other organic material is converted to ammonium sulphate
(NH4)2 SO4 by H2SO4 during digestion. This salt upon steam distillation liberates ammonia,
which is collected into boric acid solution and titrated against standard acid (0.1 N H2SO4 or
HCl) since 1 ml of 0.1 N acid is equivalent to 1.401 mg of nitrogen.
Protein estimation of sample was carriedout using Kjeldhal method (AOAC, 2000).
The Kjeldhal method can conveniently be divided into three steps.
1. Digestion
2. Neutralization
3. Titration
Reagents:

Conc. H2SO4

Digestion mixture:100 g of K2SO4 and 20 g of CU2SO4.5H2O was weighed and mixed
uniformly.

Mixed indicator: 0.1% bromocresol green and 0.1% methyl red indicator in 95%
ethanol were prepared separately. 10ml of bromocresol green was mixed with 2ml of
methyl red solution in a bottle provided with a stopper, which will deliver about 0.01
ml per four drops.

NaOH (40% solution): 40g NaOH was dissolved in 100ml of distilled water.

Boric acid (2% solution): 50mg of boric acid was dissolved in 100ml of distilled water.

Ammonium sulphate (1mg/ml solution): 50mg of ammonium sulphate was dissolved in
50ml of distilled water.

HCl (N/70 solution): 1.2315ml of conc. HCl was made up to one liter volume with
distilled H2O.
Procedure: 0.1g of sample was weighed into a kjeldhal flask,to which 0.2g of the digestion
mixture was added and digested in Kelplus– kjeldhal digester with 20ml of concentrated H 2SO4
until all the organic matter was oxidized and uniform greenish – blue digest was obtained. The
digest was cooled and volume was made up with 100ml distilled water. An aliquot of 5ml was
taken for steam distillation in kelpus distillation unit with excess of 40% NaOH solution
(10ml). The liberated ammonia was absorbed in 10ml of 2% boric acid containing a few drops
of mixed indicator.
This was titrated against N/70 HCl.
Simultaneously a standard
(Anhydrous ammonium sulphate) was also to estimate to know the amount of nitrogen taken
up by N/70 HCl. From the nitrogen content of the sample, the protein content of different
samples was calculated by multiplying with a factor of 6.25.
% of nitrogen present in given sample =
/
Sample titre value – Blank titre normality of HCl x14 x 100
Sample Weight x1000
3.4.3. Estimation of fat
Fat was determined by Soxhlet method (AOAC, 2000). 2g of the sample was accurately
weighed into a dry thimble and extracted using petroleum ether (600 - 800 bop) as solvent for
16hr. The extracted fat was collected in a previously weighed dry flat-bottomed flask and
separated from the solvent by evaporating in a hot water bath. The flask was dried in an oven at
80-1000 C and cooled until constant weight was achieved. Fat content of the samples were
expressed as g/100 g of sample.
The amount of fat present in given food sample
% fat/100 g sample =
3.4.5. Estimation of carbohydrates
Estimation of carbohydrates in the samples was carried out by Anthrone method
(AOAC, 2000).
Reagents:
1. 2.5 N HCl
2. Anthrone reagent: Dissolve 200mg of Anthrone in 100ml ice cold 95% H2SO4.
3. Stock standard glucose solution: Dissolve 100mg of glucose in 100ml of distilled water
(1mg/ml).
4. Working standard solution: Dilute 10ml of standard stock solution to 100ml with
distilled water.
Procedure: 100mg of sample was weighed and placed in boiling test tube. Then the sample
was hydrolyzed by keeping it in a boiling water bath for 3 hrs with 5ml 2.5N HCl and cooled
to room temperature. It was neutralized with solid Na2CO3 until the effervescence ceased. The
volume was made up to 100ml and centrifuged to collect the supernatant and 0.5ml and 1ml
aliquots were taken. The standards were prepared with concentrations of 0.2ml, 0.4ml, 0.6ml,
0.8ml, 1ml along with a blank and the volume was made up to 1ml in all test tubes, then 4ml of
Anthrone reagent was added followed heating for 8 min in boiling water bath. After cooling,
the red green color was read at wave length of 630nm. The standard curve was plotted with
concentration on X-axis and absorbance on Y-axis. From the standard graph, amount of
carbohydrate present in sample was calculated.
Calculation:
Amount of carbohydrate present =
3.4.6. Estimation of energy content by at water general factor system method: Energy
content was estimated by multiplying protein, fat and carbohydrate values obtained from
analysis by 4, 9 and 4 respectively (Atwater and Woods, 1896).
3.4.7. Estimation of Minerals
The analysis for calcium, phosphorus and Iron was carried out according to the
procedure given in laboratory manual of National Institute of Nutrition (ICMR)
Hyderabad.2002
3.4.7.1. Estimation of Ash (AOAC, 2005)
Foods and food products are heated to temperatures of 500 °C- 600˚C, where the water
and other volatile constituents evolve as vapors and the organic constituents were burnt in the
presence of oxygen to carbon-dioxide and oxides of nitrogen and eliminated together with
hydrogen as water. The mineral constituents remain in the residue as oxides, sulphates,
phosphates and chlorides. This inorganic residue constitutes the ash of food products. The ash
content of the samples was determined by using the method of AOAC, (2005).
Procedure:
1. The temperature of the muffle furnace was set to 600°C and empty crucibles were heated for
1 hour and then cooled in a dessicator and weighed (W1).
2. 2g of defatted sample was weighed into the crucible and weight was noted (W2).
3. The sample was kept on flame for charring and then incinerated at 600°C for 8 hours in
muffle furnace.
4. After sample was completed ashing, crucibles were transferred into the dessicator, cooled
and weighed (W3).
5. Incineration was repeated until constant weight was obtained.
Calculations:
Weight of the sample taken = W2-Wl
Weight of the ash = W3-Wl
Ash % =
=
Mineral solution preparation
The ash obtained by above procedure was moistened with glass distilled water (0.51ml) and concentrated HCl was added and evaporated to dryness on a boiling water bath.
Again 5ml concentrated HCl was added and evaporated to dryness as before. Lastly 4ml of
HCl and 5ml of distilled water were added. This solution was warmed over a boiling water
bath and filtered into the 100ml of volumetric flask using Whatman No.4 filter paper. After
cooling the volume was made up to 100ml using distilled water and suitable aliquot was used
for the estimation of Calcium, Phosphorus and Iron.
3.4.7.2. Estimation of Calcium (potassium oxalate precipitation method) (AOAC,
2000)
Principle:
Calcium in the sample solution was precipitated at about pH 4.0 as oxalate, which was
dissolved in sulphuric acid. The liberated oxalic acid was titrated with standard Potassium
permanganate solution to give pink color. From the volume of potassium permanganate
was used in titration, the concentration of calcium was calculated.
Reagents
1. 25% saturated ammonium oxalate solution
2. H2SO4
3. Silver nitrate
4. Dilute ammonia solution (1: 4)
5. Bromocresol green (0.05 % in alcohol)
6. 0.05NPotassium permanganate
7. Dilute HNO3
Precipitation of Calcium
1.
25 ml HCl extract was taken in 500 ml beaker and 50 ml of water was added.
2. To the beaker 8-10 drops of bromocresol green was added.
3. Later 10 ml saturated ammonium oxalate was added.
4. The beaker was covered with watch glass and heated to boiling.
5. Then dilute ammonia was added to the hot solution to precipitate calcium and dilute HCl
was added drop by drop until solution became yellow green (pH about 4.0).
6. The precipitate was allowed to stand overnight.
7. The solution was filtered through Whatman No 42 filter paper.
8. The beaker was washed and precipitated with 50 ml dilute ammonia solution in sample
portions.
9. Then washed with hot water until it was free of chloride or oxalate , i.e. The filtrate no
longer gives precipitation on addition of dilute nitric acid and silver nitrate
Determination of calcium
1. The filter paper was pierced with pointed glass rod and washed the precipitate was
washed into a beaker with about 100ml of water and 5ml of H2SO4
2. The filter paper was transferred into the beaker and hot water was added to make up
volume to about 150ml.
3. The content of beaker was heated to 60-70 0C and the solution was titrated with 0.05N
potassium permanganate until pink colour persisted for 30 seconds.
4. The contents were stirred gently during titration.
5.
For blank, 10ml water and 5ml H 2SO4, were titrated against 0.05 N potassium
permanganate.
Calculation
Calcium (mg %) =
Where,
W = Weight of the sample (g)
V1 =
Volume of extract made (ml).
V2 =
Aliquot of HCL extract used for precipitation (ml).
S
B
=
Volume of 0.05 N KMnO4 used against sample (ml).
=
Volume of 0.05 N KMnO4 used against blank (ml).
Note: 1 ml of 0.05 N KMnO4 = 0.001002g of Ca or 0.001 of Ca or 1 mg of Ca
3.4.7.3. Estimation of phosphorus (AOAC, 2000)
Suitable quantity of mineral solution (0.5ml) was taken in 25 ml volumetric flask to
which 1ml of each solution such as Ammonium Molybdate sulphuric acid reagent,
hydroquinone and sodium sulfate were added in an order, with subsequent shaking after each
addition. The volume was made up 25 ml with glass distilled water and rested for 30 minute
prior to color measurement. The optical density was measured at 660 nm using
spectrophotometer; an optical density of a blank was also taken. The phosphorus content was
calculated from standard curve prepared with standard phosphate solution (0.01-0.1 mg P). 1ml
std. solution = 0.01 mg of Phosphorus.
3.4.7.4. Estimation of Iron (AOAC, 2000)
The Fe in sample was determined by using flame photometry technique .The sample for
iron estimation was digested using HClO4 and HNO3. 0.5 g sample taken in a conical flask, to
this 5 ml HNO3 was added and kept overnight. Next day again 5 ml HClO4 and 5 ml HNO3
was added in sample and the sample was digested by boiling on a gas burner. Boiling
continued till colour changed colorless. The volume of the digest was made up with 100 ml
distilled water and the iron in sample was estimated by flame photometer.
3.5. Consumer evaluation.
The consumer evaluation was conducted in a sensory lab, PG&RC. About 50 members
consisted staff and post graduate students of the Post Graduate Research Center, Professor
Jayashankar Telangana State Agricultural University, Hyderabad, who had some previous
experience in sensory evaluation of different foods. The panelists were naive to project
objectives. Omelette prepared from Control and samples (A, B and C) were served to the
panelists. Samples were coded using random three-digit numbers and served with the order of
presentation and counter-balanced. Panelists were provided with a glass of water and instructed
to rinse and swallow water between samples. They were given written instructions and asked to
evaluate the products for acceptability based on its flavour, texture, taste, color and overall
acceptability using nine-point hedonic scale (1 = dislike extremely to 9 = like extremely;
Meilgaard et al., 1999 ). An overall ranking was also provided to the samples at the end.
The consumer evaluation was carried out avoiding times before and after meals to
prevent bias. The codes used for the samples were random rather than following any order to
prevent any sort of preference by the panelists. Sensory evaluation was done in one round;
three samples of omelette were prepared from three different dry instant omelette mixes with
control as without whey powder blended dry instant omelette mix.
3.6. Microbial analysis
A 10 g analytical unit of each food sample (dry instant omelette mixes: Control
sample , Sample A, Sample B and Sample C) was homogenized with 90 ml of sterile Ringer’s
solution for 2 min and then serial 10 fold dilutions were prepared with sterile Ringer’s solution
(APHA, 2001). Individual serial decimal dilutions for sample from each storage bottles were
prepared in 9 ml volume of sterile Ringer’s solution up to 1: 06 dilution of the original food
sample. Duplicate 0.1±0.5 ml or 1 ml inoculums of appropriate dilutions were spread with a
sterile glass spreader on pour plated, on the following media: for enumeration of aerobic plate
counts on spread plates of plate count agar (PCA, Hi-Media Laboratories, M 091, Bombay)
and for enumeration of yeast and moulds on spread plates of potato dextrose agar (PDA, HiMedia Laboratories, M096) which were incubated at 37° C for 48 h; Colonies were counted
from each group of micro flora and expressed as log per gram. The enumeration procedures as
described by Speck, (1975) were followed.
/
Plate no .3.7. Microbial analysis of omlette mix
3.7. Statistical analysis
The analysis of variance of the data obtained was done by using Completely
Randomized Design (CRD) and Factorial CRD for different treatments as per the methods
given by Panse and Sukhatme (1967). The analysis of variance revealed at significance of P <
0.05 level, S.E and C.D at 5 % level is mentioned wherever required.
RESULTS AND
DISCUSSION
Chapter IV
RESULTS AND DISCUSSION
The present study entitled “Development and evaluation of instant omelette mix
with egg and whey powders” was carried out to prepare an instant omelette mix from
commercially available egg powder and whey powder. Further, it was studied for its
physico-chemical properties, sensory characteristics and assessed for the microbial load
content in instant mix.
Sincere efforts were made to standardize the formulations of an instant omelette mix
by blending different proportions of freshly prepared commercially available spray dried
whole egg powder and whey powder along with other spices and condiments. The prepared
dry instant omelette mix formulation was dispersed in water to make a suspension of instant
omelette mix batter and utilized for preparation of omelette along with control sample.
The whole data obtained on various aspects of development and evaluation of instant
omelette mix is categorized under suitable heading as follows.
4.1 Composition of the omelette mix.
4.2 Nutritional composition of instant omelette mixes.
4.3 Physical properties of dry instant omelette mixes.
4.4 Physical properties of instant omelette prepared from instant omelette mixes.
4.5 Consumers evaluation of instant omelette prepared from instant omelette mixes.
4.6 Microbial analysis of instant omelette mixes.
4.1 Composition of the omelette mix:
Spray dried whole egg powder and whey powder were used as a blend to produce
nutritionally balanced dry instant omlette mix along with other spices. A preliminary dry
instant omelette mix was prepared using different proportions of whole egg powder and
whey powder having constant moisture in dry omelette mixes. The blending ratio of whole
egg powder and whey powder were finalized based on the most stable product volume and
sensory characteristics. The blend ratio of whole egg powder and whey powder to prepare
dry instant omelette mix are presented in Table 4.1. These composite instant dry omelette
mixes were used to produce the better quality of omelette with maximum retention of
nutrients in the final product.
Table 4.1. Different Composition of the instant omelette mix (100Gms)
Ingredients
Control
A
B
C
Egg Powder
90
55
60
65
Whey Powder
-
35
30
25
Salt
3.5
3.5
3.5
3.5
Chilli powder
2.5
2.5
2.5
2.5
Curry leaf powder
1
1
1
1
Onion powder
2
2
2
2
1%
1%
1%
1%
Anticaking agent (Silicon
Dioxide)
Note: This table is presented here for the second time for easy comparison of other
attributes in the results
4.2 Nutritional composition of instant omelette mixes
The nutritional composition of instant omelette Prepared from instant
omelette mixes are presented in Table 4.2. It revealed that different levels of egg
powder and whey powder significantly affected the nutritional composition of the
prepared instant omelette.
Table 4.2: Nutritional composition of instant omelette mixes (per 100 gm sample)
Instant
Omelettes
Moisture
(%)
Protein
(g)
Carbohydrates Fat
(g)
(g)
Ash
(g)
Energy
(kcal)
Control(whol
e egg powder)
A
B
C
Mean
C.D at 5%
3.81
41.7
35.5
8.2
0.98
382
4.67
4.42
4.38
4.32
29.4
31.2
32.3
33.65
46.4
44.8
43.4
42.525
5.1
5.5
5.6
6.1
0.79
0.81
0.84
0.855
349
353
353
359
0.91
0.68
0.45
0.07
0.67
0.4
0.52
0.39
0.02
0.04
0.19
0.23
4.0
80
5
2
0.7
378
level
S.E±
Whey powder
4.2.1 Moisture
The moisture content was maximum in sample A (4.67%) followed by
sample B (4.42%) and sample C (4.38%). The lesser moisture content in the sample
C and control sample may be attributed to the presence of more fat than sample B
and C. The moisture content of mixes are low enough to extend the shelf life of the
egg powders in an environment of low humidity as reported by Ndife et al. (2010).
4.2.2 Protein
The values of protein content in the instant omelette sample mixes are
presented in Table 4.2, which indicats that maximum protein content was found in
the control sample (41.7 g) than instant omelette mix sample B (31.2g) , sample C
(32.3) and sample A (29.4 g). This may be due to the addition of whey powder in
different proportion to the sample A, B and C, where control was only from egg
powder. The whole egg powder contained more protein than whey powder. The
powder; whole or egg white powder has been used in many food products such as
bakery products, confectionaries and meat products for different purposes such as
emulsifier, and texture and nutrition enhancers to increase protein and fat content.
Ndife et al., (2010) reported that egg white powder contains high proportion of
protein (62.04%) and fat (7.17%).
4.2.3 Fat
The fat content in the instant omelette sample mixes are presented in the
Table 4.2 shows that the dry instant omelette mix sample A contained less amount
of fat with an average of 5.1 g , followed by instant omelette mix sample B (5.5 g)
and instant omelette mix sample C (5.6 g).From the result it is evident that, the fat
content increased with increase in the amount of whole egg powder and decreased
with addition of whey powder in instant omelette mixes. However, there was no
much difference in fat content between in sample B and sample C
4.2.4 Carbohydrates
The mean value of total carbohydrate content in omlette mix are presented in
Table 4.2. The carbohydrate content was maximum in case of instant omelette mix
sample A (46.4 g) followed by sample B (44.8 g) and sample C (43.4 g). The
difference in carbohydrates content in the sample may be attributed the presence of
major proportion of spray dried whey powder (carbohydrate less than 5g). It is
evident that the total carbohydrates content increased with increase amount of whey
powder and decreased with increase in the amount of egg powder content in the
instant omelette mixes. However, there was not much difference found in fat content
in sample B and sample C
4.2.5 Ash
The ash content in instant omelette samples are shown in Table 4.2. There
was no much difference in ash content of instant omelette sample mix samples. Even
though the control sample contained more ash than other two instant omelette
sample mix under study.
4.2.6 Energy value
The energy content of instant omelette samples was calculated from the
amount of carbohydrate, protein and fat in the mix by considering that 1gm
carbohydrate 4 kcal energy, 1gm protein gives 4 kcal energy and 1gm fat gives 9
kcal energy. The data presented in Table 4.2 indicates very clearly that the control
instant omelette mix sample yielded more energy with an average of 382.6 kcal than
sample B (353.5 kcal) and sample C (353.20 Kcal). This was obviously due to the
presence of more fat and proteins in instant omelette sample mixes. The high food
energy value (FEV) recorded; particularly in high content of whole egg powder
(382.6 kcal) makes it particularly attractive for all sections of food formulae. Similar
results were reported by Vaclavik and Christain, (2008).
4.2.7 Mineral content of instant omelette mixes
The mineral content of the Instant omelette mixes is presented in Table 4.3.
Table 4.3: Mineral content of omelette mix(per 100 gm of sample)*
Instant
Calcium
Phosphoru
(mg)
s (mg)
Control
A
B
C
Mean
C.D
at
59.1
146.5
133.9
121.3
115.2
20.9
16.7
17.3
17.9
18.2
1.5
0.94
1.01
1.1
1.1375
5% level
S.E±
Whey
17.97
10.33
0.07
0.04
7
4.02
powder
67
38
0.75
Omelettes
4.2.7.1
The
Iron (mg)
Calcium
calcium content
of instant omelette mixes are presented in Table 4.3. The calcium content was found to be
more in sample A (146.5mg). The calcium content was increasing with the increase
quantity of whey powder.
4.2.7.2 Phosphorus
The phosphorus content of instant omelette mixes depicted in Table 4.3. shows that
it was less in instant omelette mix A (16.7mg) followed by sample B (17.3mg) and sample
C (17.9mg). This may be attributed to the variation in blending of whey powder as the
whey powder content increased phosphorus decreased. The phosphorus content was more
in the sample which was prepared with major portion of egg powder. However, there was
not much difference found in sample B and sample C. The control sample had maximum
phosphorus content (20.9mg) as there was no whey powder.
4.2.7.3 Iron
The iron content found in the instant omelette mixes are presented in Table 4.3.
From the table it is indicated that the instant omelette mix sample C contained more iron
(1.1) than sample B (1.01 mg) and sample A (0.94mg). This could be due to the lesser
quantity of egg powder in samples as egg yellow is rich in iron content (1.5).
4.3 Physical properties of dry instant Omelette mixes
4.3.1 Density of Instant Omelette mixes
The bulk density of a granular system results from the arrangement of the particles
that depends on the size distribution and the cohesion forces of the particles. The
application of tapping to a powder bed, leads to reduction of aerated volume by the
rearrangement of constitutive particles. It simulates the vibrations occurring during
conditioning, transport and storage of the powders. The aerated and packed bulk densities
are thus relevant properties to predict the conditioning and storage volumes of the powders.
The compressibility is related to the flowability of a powder.The higher the compressibility,
higher the tendency of compactness of a powder bed and worsening of the ability to flow.
Table 4.4: Physical properties of Instant omelette mixes
Physical Properties
Dry
Instant
Omelette
mixes
Density
(g/cc)
Titratable
acidity
(%)
Control
0.73
0.08
Solubility of Foaming stability
the powder
(%)
(%)
93.62
16.64
A
0.86
0.12
90.75
13.72
B
0.79
0.11
91.43
15.86
C
0.76
0.10
0.135
91.94
16.03
91.93
15.57
0.01
0.63
0.53
0.366
0.392
0.2664
Mean
0.78
C.D at 5%
0.47
level
S.E±
0.353
* Each value is an average of three determinations
The effect of blending ratios of different egg powder and whey powder in instant
omelette mixes on the packed density of the instant omelette mixes are shown in the
Fig.4.1. The mean score indicated that the packed density increased with the optimum
level of whey powder in the instant omelette mix. The packed density was less for control
sample (0.73) than sample C (0.76) and sample A (0.86). However, the magnitude of
increase was less in case of sample B and Sample C, because of addition of whey powder
as indicated in figure 4.1 and Table 4.4.
Fig 4.1: Packed density of instant omelette mixes
4.3.2 Titratable acidity of instant omelette mixes
From the results presented in the Table 4.4, it can be explained that especially in
sample B the acidity 0.11% shows that the whey proteins supported foam formation.
Increase in the proportion of whey powder in the sample A with 0.12% acidity did not
affect the foam capacity, in spite of much poorer foaming properties of the sample A this
acidity level. Increase in the stability of foam prepared from a blend of egg powder and
whey powder was comparable to the foam from the component formed separation from egg
and whey indicated synergistic interactions of egg white and whey proteins at an acidity of
0.10%. According to Howell and Li-Chan, (1996), this is a result of involvement of
electrostatic forces in the interaction between positively charged lysozyme and the
negatively charged whey proteins. The lysozyme can interact electro statically with the
opposite charged proteins resulting in the lowering of the net charge in the mixed
aggregates. The lower net charge reduces the repulsions between aggregates, facilitating
their adsorption and contributes to their closer contact at the air–water interface
4.3.3 Solubility of instant omelette mixes
The solubility index, which is one of the physical properties of the protein, showed
high values of 93.62% for control sample and 90.75% for sample C. However, the
solubility of samples B and C was not different with each other. The solubility of the
instant omelette mixes is presented in Table 4.4. Solubility of powders may vary with the
final protein content in the sample which also indicated the low levels of protein
denaturation (Wong and Kitts, 2003).
4.3.4 Foaming stability
Changes in structural properties of whole egg powder may lead to changes in
foaming, emulsifying and gelling abilities (Song et al., 2009). These functional properties
play an important role in the manufacture of various food products. The foaming ability is
related to the rate at which the surface tension of the air/water interface decreases. The
foaming stability data of instant omelette mixes are shown in Table 4.4. Sample A has
significantly lower (P < 0.05) foaming stability than sample B and sample C and this was
likely to be due to the variation in composition of spray dried whole egg powder content in
the instant dry omelette mix. However the control sample had the maximum foaming
stability than the other samples. The inferior foaming stability of instant omelette mix
implies that it may not be suitable for use in bakery products as the amount of foam and its
stability influence the volume and appearance of final Instant omelette.
The fat content of these components must have played a significant role in the
stability of foam. Lipids are known to enhance the emulsification process in foods but they
diminish their foaming potentials, similar kind of results were reported by Marques, (2000).
4.3.5 Emulsification properties
To investigate emulsifying ability of control, sample A, sample B and sample C
omelette mixes were mixed with palm oil. Then the emulsion was taken and mixed with
0.1% SDS for 0, 2, 4, 6, 8, 10 and 20 min. The dilution of emulsions with 0.1% SDS
solution produced turbid dispersion. The concentration of the diluted Instant omelette mix
emulsion was proportional to the absorbance up to about 0.4 (Pearce and Kinsella, 1978).
The emulsification properties of instant omelette mix is presented in Table 4.5. which
shows that the turbidity of Instant omelette mix emulsion decreased upon standing from 0
min to 20 min . During standing times the turbidity of control instant omelette mix sample
emulsion was higher than that of other samples, indicating a lower emulsifying ability of
the other samples compared to control. Low emulsifying ability of sample C could pose
negative impact on the overall flavor of final product.
Table 4.5. Emulsification properties of instant omelette mix
Absorbance at 500nm
Time in
Min.
Control
0
0.4
2
0.39
4
0.36
6
0.35
8
0.34
10
0.33
12
0.32
14
0.3
16
0.29
18
0.2
20
0.19
Sample-A
0.2
0.19
0.18
0.18
0.16
0.14
0.12
0.11
0.1
0.09
0.08
Sample- B
0.31
0.29
0.27
0.26
0.25
0.23
0.2
0.19
0.17
0.15
0.13
Sample C
0.36
0.34
0.32
0.3
0.28
0.25
0.23
0.2
0.18
0.17
0.16
4.4 Physical property of instant omelette prepared from instant omelette mixes
4.4.1 Volume measurement of omelette
Freshly prepared instant omelette (sample A, B and C) were used to compare with
the volume of freshly prepared control sample.
A high-quality instant omelettes are
produced when the dynamic events emulsification, foaming etc takes place. The volume of
instant omelette sample B was found to be significantly by higher (P < 0.05) than that of
other Instant omelette samples (sample A and sample C (Table 4.6). This was expected
since the other samples had inferior foaming stability as compared to sample C (Table 4.4),
thus affecting the volume of the omelette prepared. This correlation was consistent with the
finding of Song et al. (2009), who reported the foaming ability of egg white protein was
directly proportional to the cake volume. A higher volume in instant Omelette with lower
density implies that more gas was incorporated in the omelette. Omelette formulated with
egg had higher and wider range of volume and density compared to those with whey
powder. This was expected as whey powder is added and a similar finding was obtained by
Abdul Hussain and Al-Oulabi, (2009). Cakes with bigger volumes and lower density were
produced as the protein concentration increased.
Table 4.6. Volume of instant omelette prepared from dry instant omelette mixes
Instant
Control
A
B
C
Mean
omelette
Volume
(ml)
C.D
at S.E±
5% level
12.06
10.61
11.26
11.24
11.29
0.47
0.567
Fig 4.2. Volume of instant omelette prepared from dry instant omelette mixes
4.5 Consumer evaluation of instant omelette
About 50 consumers were given the Omelette samples for evaluation of
organoleptic characteristics viz. appearance, colour, taste, flavour, texture and overall
acceptability. It was served hot on the day of preparation. The average scores recorded are
presented and discussed (Table 4.7 and Fig 4.3) under suitable quality attributes.
Table: 4.7 Mean consumer scores of instant omelette prepared using instant
omelette mixes
Instant
omelette
Control(whol
e egg powder)
A
B
Sensory attributes
Appearance Colour Flavour Texture Taste
Overall
acceptability
8.3
8.6
8.4
8.8
8.6
8.9
7.5
7.0
7.0
7.9
7.0
7.7
7.8
7.9
7.8
8.9
8.2
8.5
C
7.2
7.4
7.2
8.0
8.0
7.7
Mean
C.D at
level
S.E±
7.7
7.7
7.6
8.4
8.3
8.2
0.47
0.7
0.63
0.53
0.67
0.6
0.23
0.35
0.31
0.26
0.29
0.29
5%
4.5.1 Appearance
The mean scores for appearance of instant omelette are presented in Table 4.7.
Better scores were obtained for the control sample (8.3) followed by instant omelette
sample B (7.8), sample A (7.5) and sample C (7.2). However, the difference in
appearance of instant omelette sample was very less, as they were rated as liked
moderately.
The appearance of instant omelette samples (Fig 4.3) revealed that there was no
significant effect on the appearance of instant omelette. However, the sample B with
blend ratio of 60:30 (whole egg powder: whey powder) was on par with the control,
with scores of 7.8 in case of appearance of the instant omelette.
4.5.2 Colour:
It may be visualized from Table 4.7, that instant omelette did not exhibit much
difference with regard to colour of the final product with scores ranging from 7.0 to
8.6. The color of control sample was more acceptable (8.6) followed by sample B (7.9)
both were rated between like moderately to like very much. It was interesting to note
that samples A and C were rated as like moderately. One of the reactions related to
colour change in dry systems containing amines and reducing sugar is non-enzymatic
browning (NEB or Maillard reaction). The reaction in HEW is likely due to the
presence of a small amount of glucose (reducing sugar, 60.07%). Although the glucose
content was very small, it will react with both lysine and the N-terminal groups of the
vast amount of small HEW peptides (Rao & Labuza, 2012)
4.5.3 Flavour:
The mean scores for flavour of instant omelette samples presented in Table 4.7,
indicate that flavour was more acceptable for sample B (7.9) as compared with Control
(8.6). Further sample C was rated better than sample A.
4.5.4 Texture
It can be observed from table 4.7, that combination of whole egg powder and
whey powder in Instant omelette mixes exhibited wide differences with regard to the
texture of the final product ranging from 7.9 to 8.9. At the highest percentage of Whey
powder substitutions for egg powder in instant omelette mix and resulted in increased
hardness (mm) of omelet. The results are highly correlated with the findings of Alfaifi,
M.S. and Stathopoulos, C.E (2010). This could be because of the denatured proteins
exhibiting substantial hydrophobic interactions, resulting in increased amount of bound
water (Eissa and Khan, 2006).
Maximum score was obtained for the sample B (8.9) followed by control (8.8)
and both were rated as like very much. It was interesting to note that both sample A and
C had got similar scores (8.0). It was also observed that the blended proportion of spray
dried whole egg powder and spray dried whey powder had significant effect on the
texture of instant omelette but its effect was desirable in the combination ratio of whole
egg powder: whey powder of 60: 30.
4.5.5 Taste
The mean scores for taste are presented in the Table 4.7 and Fig 4.3. The best
taste observed was in case of sample B which was on par with the control followed by
sample C, As where sample A scored less i.e. 7.0 in comparison to control and other
samples. It is important to note from the present findings those taste was decisively
governed by the level of egg powder in dry instant omelette mix and there was also an
after taste reported by judges depending on level of spices added to the instant omelette.
4.5.6 Overall acceptability
It is seen from the results that variation do exist in the overall acceptability
scores. All the combinations of spray dried whole egg powder and whey powder in
instant omelette mixes scored between like moderately to like very much. Highest score
was observed in control sample. It was interesting to note that both the sample A and C
scored same i.e. 7.7. The overall acceptability of instant omelette could be attributed to
the different characters of appearance, colour, taste, flavour and texture of the final
product. It is revealed from the scores of the overall acceptability that the spray dried
whole egg powder and spray dried whey powder can be successfully mixed in the ratio
of 60:30 to produce a better acceptable product.
After organoleptic assessment of instant omelette, the instant omelette mix
prepared from spray dried whole egg powder, spray dried whey powder, salt and spices
in the ratios 60:30:10 respectively have the best sensory acceptability than remaining
other two samples. Therefore this combination was best for the instant omelette.
4.6 Microbial analysis of Instant omelette mixes
The results of Microbial analysis of the instant omelette mixes after 3 months of
storage is shown in table 4.8
Table 4.8 Microbial analysis of the instant omelette mix.
S.No
Instant
omelette
Initial
Total plate Initial
count after 3
months
Yeast and
mould
count after
3 months
1
CONTROL
Nil
Nil
Nil
Nil
Nil
Nil
Nil
Nil
Nil
Nil
Nil
Nil
Nil
Nil
Nil
Nil
2
3
4
SAMPLE- A
SAMPLE -B
SAMPLE- C
On microbial analysis showed in the table 4.8 that there was no growth for the
test of total plate count (TPC) and negative results were obtained for the enumeration of
yeast and moulds using samples of Instant omelette mixes after 3 months of storage at
ambient temperature (27-30ºC).as the mixes were stored in air tight packages with no
change in moisture , there was no microbial growth. No growth of microbes in the
instant omelette mix could be due to thermal processing, low water activity (a w) values
of the product, hygienic practices followed during processing and storage and
antibacterial effects of spices and salt (Grohs and Kunz, 1999; Grohs et al., 2000). The
results in the present investigation clearly indicate that the dried instant omelette mix
samples are microbiologically safe when packed in metalized polyester bags and stored
at 27 ± 2°C for 6 months. The shelf stability of the product was achieved by keeping a
low moisture content in the final mix (4.42 ± 1.02%).
SUMMARY AND
CONCLUSION
Chapter V
SUMMARY AND CONCLUSION
The present investigation entitled “Development and Evaluation of Instant
omelette mix with Egg and Whey powders” has been carried out and the results obtained
are summarized as below.
The development of dry instant omelette mixes by blending different proportions of
pasteurized spray dried whole egg powder (hen), whey powder, keeping other ingredients
constant. The instant omelette mix samples were prepared by blending different levels of egg
powder and whey powder, compared to control (90% egg and 10% spices. Physical and
nutritional properties of the blends were analyzed for the same and conclusion were derived.
Pasteurized spray dried Hen Whole egg powder and whey powder were procured
from local industries. Iodized salt, chilli powder, onion powder, curry powder were procured
from were procured from local market of Hyderabad.
Further the dry instant omelette mixes blends were prepared by blending pasteurized
spray dried hen whole egg powder, whey powder, iodized salt, chilli powder, onion powder,
curry leaf powder in different proportions on dry weight basis. The blends were standardized
against fresh omelette prepared from whole egg powder and spices by considering the ease in
process as well as better acceptability of products in terms of physical characteristics as well
as sensory attributes.
The nutritional composition of instant omelette mixes indicated that the control
sample had better nutritive value than other instant omelette mixes. The nutritional
composition of instant omelette mix sample B (i.e. more accepted in terms of physical
properties ) prepared by pasteurized spray dried hen whole egg powder: whey powder
:iodized salt: chilli powder: curry leaf powder: onion powder: anti-caking agent in the ratio of
60:30:3.5:2.5:01:02:01, This combinations contained optimum protein (31.2g/100g), more
carbohydrates (44.8g/100g) and more minerals viz. calcium (133.9mg/100g), phosphorus
(17.3mg/100g) and iron (0.1.01mg/100 g) than that of control sample. It was also found to be
having less fat (5.5 g/100g) than control instant omelette mix sample (8.2g/100g). This may
be attributed to large quantity of whey powder in the dry instant omelette mix sample
The physical properties of the dry instant omelette mixes were analyzed, the values
revealed that the packed density was less for control sample (0.73g/cc) than sample C
(0.76g/cc) and sample-A (0.86g/cc). However, the magnitude of increase was less in case of
sample B (0.79g/cc) and Sample C. Compressibility is related to the flow ability of a powder
hence higher the compressibility, higher the tendency of compression a powder bed and the
lowest ability to flow. The difference in the physical properties of instant dry omelette mixes
may be due to the varying proportions of whey powder in the instant dry omelette mixes.
With titratable acidity of 0.11% in the instant omelette mix sample B, the whey
proteins support the foam formation. The increase is proportion of whey powder in the
sample A at acidity 0.12% did not affect their foam capacity, in spite of much poorer foaming
properties of the sample A at this acidity level. The stability of the foams prepared from a
blend of egg powder and whey powder mixtures increased, compared to the foams from the
components foamed separately indicating synergistic interactions of egg white and whey
proteins at acidity 0.10% (sample C).
The solubility index, which is one of the physical properties of the protein, showed
high values of 93.62% for control sample, 90.75% for sample C. However, the solubility of
sample B and C is not much different from each other. Solubility of powders may vary with
the final protein content in the sample and it is also indicated by low levels of protein
denaturation.
Sample A (13.72%) had significantly (P < 0.05) lower foaming stability than sample
B (15.86%) and sample C (16.03%) and this is likely to be due to the variation in
composition of spray dried whole egg powder content in the instant dry omelette mix.
However, control sample (16.64%) had the maximum foaming stability than all other
samples. The inferior foaming stability of instant omelette mixes implied that it may not be
suitable for use in food products like bakery foods as the amount of foam and its stability
influence the volume and appearance of final instant omelette.
Emulsification properties of control instant omelette mix sample emulsion was higher
than that of other samples, indicating a lower emulsifying ability of the other samples
compared to control. Low emulsifying ability of sample C could pose negative impact on the
flavor of final product.
The volume of instant omelette sample B (11.26 ml) was found to be significantly (P
< 0.05) higher than that of other instant omelette samples (sample A (10.61ml) & sample C
(11.24 ml).Since other samples had inferior foaming stability as compared to sample B
(15.86%), thus affecting the volume of omelette prepared. This correlation is consistent with
the findings of various researchers who reported that the foaming ability of egg white protein
was directly proportional to cake volume. A higher volume instant omelette with lower
density implies that the omelette contained and retained more gas cells.
The instant omelette prepared dry instant omelette mixes were analyzed for their
organoleptic evaluation by panel of 12 members. The members were asked to identify the
best quality product by comparing with the control sample. The instant omelette mix sample
B (pasteurized spray dried hen whole egg powder: whey powder: iodized salt: chilli powder:
curry leaf powder: onion powder: Anti-caking agent in the ratio of 60:30:3.5:2.5:01:02:01)
was found to be having better sensorial quality than sample A and C. The mean scores for
the overall acceptability of instant omelette sample B (8.2), as rated on 9 point hedonic scale.
It can be concluded from the scores of the overall acceptability that the whole egg powder
and whey powder can be successfully mixed to the extent of 60:30 parts respectively to
produce a better acceptable product, with higher protein content.
Microbiological analysis showed no growth for the test of total plate count (TPC)
,yeast and moulds were obtained for the using samples of instant omelette mixes after 3
months of storage at ambient temperature (27-30ºC).as the mixes were packed in the airtight
conditions, there fore there was no change in moisture content.
Thus ,it may be concluded that the instant omelette mix samples prepared by blending
different proportions of pasteurized spray dried hen whole egg powder, whey powder and
keeping constant other ingredients like iodized salt, chilli powder: curry leaf powder: onion
powder: anti-caking agent which were analyzed for their physical, nutritional and consumer
acceptability. The instant omelette mix sample-B (pasteurized spray dried hen whole egg
powder: whey powder: iodized salt: chilli powder: curry leaf powder: onion powder: anticaking agent in the ratios of 60:30:3.5:2.5:01:02:01) was found to be more acceptable with
respect to mentioned quality parameters.
This mix can be very well need for improving the protein status of an individual.
Further studies may be conducted such as feeding trails to see the improvement of protein
quantity. Consumers evaluation of the product for acceptance.
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APENDICES
APPENDIX- A
CONSUMER EVALUATION SCORE CARD OF OMLETTE PREPARED
FROM INSTANT OMELETTE MIXES
Directions: Please taste the samples one by one and evaluate them for the following parameters on
hedonic scale as given at the end of form. It is very important to rinse mouth thoroughly with clean water
after evaluation of each sample.
Name of the consumer: ______________________________
Age:_____________________
Sex: Male /Female
Signature: ______________________
Date: ___________
Attributes
Appearance
Colour
Flavour
Texture
Taste
Overall
Acceptability
Hedonic scale
9
Like extremely
8
Like very much
7
Like moderately
6
Like slightly
5
Neither like nor dislike
4
Dislike slightly
3
Dislike moderately
2
Dislike very much
1
Dislike extremely
Samples