Production of Maltodextrin and Glucose from Cassava Starch by

Table of Contents
Production of Maltodextrin and Glucose from Cassava Starch by Enzyme
Hydrolysis using Locally Produced �-Amylase and Glucoamylase
TERESITA M. ESPINO*, RICHARD D. TAMBALO, JACK DEODATO C. JACOB,
FIDES Z. TAMBALO and PAUL ARJUNE OLAYRES
National Institute of Molecular Biology and Biotechnology (BIOTECH), University of the
Philippines Los Baños, College, Laguna, Philippines 4031
(*Corresponding author; e-mail: [email protected])
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Introduction
The Philippines, being a major agricultural country has an abundant supply of raw
materials that can be utilized for the production of starches. Local sources of starch are
grains (e.g. rice, corn, sorghum, wheat) and roots and tubers (sweet potato, cassava, potato,
arrowroot).
On a worldwide basis, cassava has now become the fourth most important source of
calories after rice, sugarcane and maize. Cassava is highly productive which under
favorable conditions yields up to 90 tons fresh roots per hectare which is equivalent to 27
tons of dry mass, 90% of which is pure starch. Under harsh environments, particularly
where prolonged drought and poor soils are the major constraints for successful production
of other staple food crops such as cereals, cassava crops produce reasonable yields [1]. This
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characteristic has earned cassava the name 'famine fighter'. Often, cassava is the only crop
people in the subtropics and tropics have to eat when other crops have died from drought.
As a crop, cassava is one of the most efficient producers of starch, which constitutes about
85 percent of the storage root tissue dry-matter content. Annual production of cassava
starch for industrial uses is about 800,000 tonnes, and originates mainly from Brazil (for
the national market) and Thailand (for export to Japan and the EC) [2].
Starch is a high polymeric carbohydrate, with a molecular formula of (C6H10O5)n
where n varies from a few hundred to over one million. Starch can be cooked as food or
can be used as ingredient in foods. Moreover, it is used by the pharmaceutical, textile,
paper and confectionery industries as binders, fillers and additives [3]. Starch can also be
used as substrate for the production of high value products such as maltodextrin and
glucose.
Glucose, also called dextrose, is a moderately sweet sugar found in fruits and
vegetables. It is mainly used in the baking, beverage (beer and malt liquor), canning,
confectionery and dairy industries. It is also used for the production of intravenous fluids
for medical and veterinary purposes [4]. Glucose can also be used for the production of
ethanol and lactate, the raw material for biodegradable plastics [5].
Hydrolysis of starch into maltodextrin and glucose could be done either by acid
hydrolysis, enzymatic hydrolysis or combination of both. Studies conducted showed that
the use of microbial enzymes for starch hydrolysis is rapidly being utilized instead of acid
hydrolysis [6]. The enzymes that are primarily involved in starch hydrolysis are amylases
and glucoamylases.
Considering that starch is universally available, an appropriate technology is urgently
needed to produce high value products such as glucose and maltodextrin. Development of
economically viable technologies will produce positive chain effect, which will benefit the
farmers, food processors and finally consumers.
Materials and Methods
Materials
Food grade cassava starch was purchased from the local market while the �-amylase
and glucoamylase used were produced at BIOTECH, UP Los Baños using AM-1 bacterial
isolate and the fungal culture, Aspergillus niger BIOTECH 3104, respectively. Glucose and
maltodextrin standards were purchased from Sigma Chemical Co.
Maltodextrin and glucose production
Optimized conditions obtained by Espino et al. [7] were utilized for the laboratory
scale production of maltodextrin and glucose from cassava starch using BIOTECH
bacterial �–amylase and fungal glucoamylase. Production was carried out using a 30 L
bioreactor.
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High performance liquid chromatography (HPLC) analyses of samples
Samples
for HPLC were analyzed according to the method prescribed by Merck [8] using
acetonitrile-water (70:30) as the mobile phase at 1 mL/min. A Lichrosper® 100 NH2
column 4�250 was used in the analysis. Glucose and maltodextrins (maltose, maltotriose,
maltotetraose, maltopentaose, maltohexaose and maltoheptaose) were used as standards.
All standards used were HPLC grade.
Determination of physical and chemical properties of the produced glucose monohydrate
Physical properties (melting point, solubility, odor and taste, color of solution and
microscopic particle count test) and chemical properties (moisture content, pH, chloride
content, specific rotation, sulfate level, acidity, presence of residue on ignition, presence of
heavy metal expressed as lead, dextrin content, presence of unhydrolyzed starch, presence
of 5-hydroxymethylfurfural and other related substances and dextrose level) of the
BIOTECH produced glucose monohydrate from cassava starch were determined to
ascertain the quality of the product and for comparison with the established USP standards.
Toxicological evaluation of the glucose product
The method of AOAC [9] was
adapted for the preparation of water and oil extracts to be used in the chick embryo assay
for toxicological evaluation. Fertile chicken eggs were purchased from the Institute of
Animal Science (IAS), U.P. Los Baños.
Total plate count
Serial dilutions of the glucose product (DF 5, 10, 20 and 50) were
pour-plated in Plate Count Agar (PCA) for the determination of total microbial count.
Results and Discussion
Maltodextrin and glucose production
Optimized conditions obtained by Espino et al. [7] were utilized for the laboratory
scale production of maltodextrin and glucose from cassava starch using BIOTECH
bacterial �–amylase and fungal glucoamylase. Production was carried out using a 30 L
3.28
8.67
15.58
3.31
solvent
8.71
glucose
maltose
15.67
3.31
(b)
(a)
Fig. 1. High Performance Liquid Chromatograms of standard (a) and
BIOTECH-produced glucose derived from cassava starch (b).
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bioreactor.
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Table 1. Comparison of physical, chemical and microbiological properties of the
BIOTECH-produced dextrose monohydrate from cassava starch with
the United States Pharmacopoeia (USP) standards.
Parameter
BIOTECH dextrose
monohydrate from
cassava starch
USP
Requirements
Identification test
Passes
Passes
Odor
Taste
Color of solution
Melting point, 0C
Solubility,
g/100 mL H2O
Specific rotation, degrees
Moisture content, %w/w
Residue on ignition, %w/w
None
Sweetish
Colorless
77.67 ± 0.44
None
Sweetish
Colorless
83.00
96.40 ± 0.94a
47.02b
+52.33 ± 6.18
7.85 ± 0.75
0.021 ± 0.00
+52.6 to +53.2
7.5 to 9.5
�0.100
Acidity, as ppm CaCO3
Chloride, ppm
18.38 ± 3.19
8.20 ± 6.37
�5.00
�5.00
Sulfates, ppm
Dextrins
Soluble starch
Lead, ppm
pH
Particulate matter,
particles/mL:
(25�m)
(10 �m)
5-hydromethylfurfurals
and related substances,
Abs284nm
Microbial limit, CFU/mL
Possible toxins
Assay for dextrose, %w/v
�5
None
None
0.56
3.92 ± 0.31
�5
None
None
<1.00
3.2 to 6.5
5.33 ± 1.78
9.17 ± 4.11
2
12
0.192 ± 0.02
�0.250
0
None
4.75 ± 0.29
0
None
5.00
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������ ��� Preliminary toxicological evaluation of the glucose
product from cassava starch using chick embryo assay
(AOAC, 1980)a.
Number of
eggs
injectedb
Number
of live
eggs
Number
of dead
eggs
%
Survivalc
10
10
0
100
10
10
0
100
3 Water-soluble sample
10
9
1
90.0
4 Sterilized coconut oil
(CONTROL 3)
10
9
1
90.0
5 Oil-soluble extract
10
9
1
90.0
Treatment
Uninjected
(CONTROL 1)
2 Sterilized distilled
water (CONTROL 2)
1
a
Average of two (2) trials.
Incubated at 38�C for 14 days after injection.
c
% survival = number of live eggs X 100
number of eggs injected
b
Conclusion
Two BIOTECH produced enzymes namely AM-1 bacterial �-amylase and AN
fungal glucoamylase were used for the production of maltodextrin and glucose from
cassava starch. A high 90-95% yield of glucose powder was obtained after lyophilization of
the glucose monohydrate syrup. Results showed that majority of the physico-chemical
properties of the dextrose produced from cassava starch complied with the USP set of
standards. Total plate count of the unfiltered and filtered glucose solutions were <10
CFU/mL and 0, respectively. Results of the chick embryo assay showed that the glucose
product is safe from oil soluble and water soluble toxins as shown by the high percent
survival of 90-100% recorded for all the injected treatments.
Acknowledgement
This study was part of the project entitled, “High Value Products from Starches of
Rootcrops by Enzyme Biotechnology” funded by the Agribusiness and Marketing
Assistance Service (AMAS) Program through Region IV Department of Agriculture. The
research on �–amylase was part of the project entitled, “Production of �–amylase for Food
and Other Industrial Applications” funded by the Philippine Council for Industry and
Energy Research and Development (PCIERD), DOST.
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Table of Contents
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