EDIBLE COATING FOR FRUIT AND
VEGETABLES: Beewax coating for strawberry – case study
ERIKA PARDEDE
1
1.
2.
1
2
FACULTY OF AGRICULTURE
AGRICULTURE, HKBP NOMMENSEN UNIVERSITY – MEDAN –INDONESIA
Presented on DAAD Alumni Autumn School 2009 “Post-harvest Technology and Renewable Energy”, 1st to 12th
November 2009, Georg August University of Goettingen - Germany.
PART I
INTRODUCTION
PROLONG SHELFLIFE OF FRUIT & VEGETABLES
EDIBLE COATINGS
PART II
BEEWAX COATING FOR STRAWBERRIES
PART I
INTRODUCTION
PROLONG SHELFLIFE OF FRUIT & VEGETABLES
EDIBLE COATINGS
FRUITS & VEGETABLES
Fruit & Vegetable : perishable products
F & V are remain as living tissue
Quality : appearance, texture, flavour &
aroma, nutritive
t iti value,
l
safety.
f t
Quality
affected
pre
preand
Qua
ty is
sa
ected by p
e-harvest
a est a
d post
harvest factors
PROLONG SHELFLIFE OF FRUIT &
VEGETABLES
Pre-cooling
PreCuring
Controlling temperature (Cold storage)
Controlling atmosphere (MAP)
Packaging
Coating edible)
Functional properties of an edible coating on fresh
f it and
fruits
d vegetables
t bl
(source: Lin & Zhao, 2007)
Volatile compounds
Coating layers
Functional ingridients can be
incorporated in coatings :
• antioxidants
•Antimicrobials
•Flavours
•colourants
FRESH PRODUCE
(water, carbohydrate, proteins,
pigments, aroma)
Gases
G
(O2/CO2/Ethylene)
Moisture
EDIBLE COATINGS
Moisture barrier
Gas barrier
Restrict exchanging volatile compounds
Physical protection
Carrier for functionals ingridients
EDIBLE COATINGS
Lipid based coatings: parafin, waxes
waxes,…
,…
Polysaccharide--based coatings: starches
Polysaccharide
starches,
chitosan, aloe vera, seaweeds,…
seaweeds,…
P t i -based
ProteinProtein
b
d coatings
ti
: zein,
i gluten,
l t
…
Combination
Co
b at o
PART II
BEEWAX COATING FOR STRAWBERRIES
Beewax emulsion (oleic acid thiethanolamine
beewax)
The coating solution used in this work was prepared
from the formulation defined through prepre-experimental.
Three different concentrations of bee waxes emulsion in
water i.e 12 %, 8%, and 4% have been prepared, with
addition of oleic acid and triethanolamine as emulsifiers.
M t i l & Methods
Materials
M th d
M t
Mature
strawberries
t
b i were h
harvested
t d ffrom commercial
i l llocall
farms in the area of Daulu, Berastagi, North Sumatera and
transferred to the laboratorium.
Strawberries were washed in running tap water and allow to
drying with muslin cloth prior to application of the coating
solution.
solution
Strawberries dipped in formulated emulsion (coatings) at
room temperature and allowed to dry again before storing at
re
room temperat
temperature.
Three (3) treatments were performed to strawberries and will
be compared
p
with untreated g
group
p ((control g
group)
p)
RESULTS & DISCUSSION
Analysis on:
Texture
Color development
Total soluble solid
Titrateability
Ascorbic acid content
TEXTURE
0,5
Texturre (g/mm)
0,4
Control
0,3
4%
8%
0,2
12%
0,1
0
0
1
2
3
4
5
6
Time (days)
•Coating significantly affect the texture of strawberries, but only to
the 2
2--days of storage by beewax 12%
•Coating can not controlling the integrity and firmness of strawberries
during storage.
Colour development
Score 4
Score 3
Score 2
Score 1
Colour development
Colour de
evelopment
5
4
Control
3
4%
8%
2
12%
1
0
0
1
2
3
4
5
6
Time (days)
•Beewax coating has an effect on colour by slowing down the development
of strawberries colour.
•The 12 % beewax could better retain the colour development until 3 to 4
days of storage.
U
Uncoated
d
Beewaxx 12 %
0 - day
4 - day
6 - day
Total Soluble
e Solid ( o Brix))
Total soluble solid
6
5
Control
4
4%
3
8%
2
12%
1
0
0
1
2
3
4
5
6
Time (days)
•It seems that bee wax coating contributed to the Total soluble solid (TSS)
•TSS is increasing during storage
•Up to 3 days of storage, coating could retarding the TSS content of strawberry
Titrateable acidity
Titrateable acidity (%)
5
4
Control
3
4%
8%
2
12%
1
0
0
1
2
3
4
5
6
Time (days)
•Both coated and uncoated strawberries showed a gradually decreasing in
acid content during storage
•There was an indication that coating contributed to the acid content of sample.
Ascorbic acid
Ascorbic a
acid (mg/100 g))
600
500
Control
400
4%
300
8%
200
12%
100
0
0
1
2
3
4
5
6
Time (days)
•Decreasing on Ascorbic acid found during storage of both coated and
uncoated strawberries
•Coating also contribute to the Ascorbic Acid content
•Starting by second days of storage there was no difference between
coated
t d and
d uncoated.
t d
Conclusions
Beewax as coating is promising
Strawberry: early maturity stage
Challenges:
 Need further research on other suitable
produces
p
oduces
 Possibility of blending different coating
 Seek further on combination with
packaging
p
g g at different storage
g condition