Proposal for Reducing the Fat Content of Fried Snacks

Proposal for Reducing the Fat Content
of Fried Snacks
Executive
Summary:
The Seeker stated that: any proposed
solution should address the following Technical Requirements:

Any additive or treatment should enable reduction of
fat content by 20% or more
Any additive or treatment should be stable at 360 - 370
° F
Any additive or treatment should not affect the
organoleptic (taste, aroma, texture, or appearance) properties of the
finished product
Any additive should meet Generally Regarded As Safe
(GRAS) Standards
Any proposed additive or process should not negatively
influence consumer acceptance of the product (e.g. label perception).
Any proposed additive or treatment should be
cost-effective for use in the large scale production of snack foods.
The proposed method should offer the Seeker client
"freedom to practice" or be available for potential licensing.
There should be no third party patent art preventing the use of specific
equipment and materials for their commercial application.
.
Legumes and their blends are widely used
for the production of papads. Papads with low fat content would be a boon to
populations looking for low-calorie foods with retention of organoleptic
profile. Judicious blending of legumes such as black gram, green gram, bengal
gram, red gram and cowpea revealed that low-fat fried papads could be prepared
from a blend of 40 : 36 : 24 blend of bengal gram: black gram : green gram
flours. The blend had 15.6% lower fat content as compared to the control
prepared from black gram flour alone. Other quality parameters such as expansion
ratio, texture in terms of crispness, colour and overall organoleptic quality
were also evaluated. Cereals Legumes, legumes and their blends are widely used
for the production of a range of fried products with low fat content would be a
boon to populations looking for low-calorie foods with retention of organoleptic
profile. Judicious blending of cereals and legumes such as chickpea, cowpea,
green gram, black gram, rice, wheat and amaranth revealed that low-fat fried
snacks could be prepared from a blend of 64: 16: 20 of cowpea : chickpea :
green gram flour. The blend had 27.8%
lower fat content as compared to the control prepared from checkpea flour alone.(Ref.1,
and 3). Barley has emerged as a new
source of dietary fiber with promising evidence of health benefits, viz. both
hypoglycemic effects in vivo. In the present study, incorporation of both
pearled and whole barley at varying levels (5
to 25%) on the quality characteristics of bread – including physical,
rheological and sensory attributes, (viz. loaf volume, texture, taste and
flavour), breads having 10% whole barley (WB) flour, or 15% pearled barley (PB)
flour were found to be acceptable. Both WB and PB bread resulted in
significantly lower post-prandial blood glucose than standard white bread. Two
hours after the test meal, both the experimental breads showed a higher satiety
score than did the white bread. The results reveal that by incorporation of
barley at suitable levels, it is possible to formulate breads that would cater
to the therapeutic needs of various targeted population such as diabetics and persons
suffering from coronary heart diseases or other disorders with impaired
carbohydrate /lipid metabolism.(Ref.2).

Akara, a fried
finger food made from cowpeas (Vigna unguiculata),
is popular in West
Africa and has been
shown to be acceptable to American consumers. Akara is, however, a high-fat
food (about 31%, dry wt basis). We determined the effects of incorporating two modifiers,
high amylose cornstarch or extruded cowpea flour, on akara fat content and consumer
acceptability. The modifiers were used at the 10% level. Akara fat content was reduced
by 26.1% with cornstarch and by 36.8% with extruded cowpea flour. There were no
significant differences in sensory ratings among samples, and all samples
received acceptable ratings (6 = like
slightly) for overall liking.(Ref.4). .
Pre-drying and subsequent dipping in a sugar solution
(‘sugar dipping’) is a potentially effective process for pre-treatment of
potato crisps. In this study, potato crisps were blanched, pre-dried, and
dipped in the solution of sugar (23.07 wt%) 2 s before frying at
180 °C. There was a significant reduction in the oil content of crisps
observed. Crisps that had been treated had about 30% less oil than the samples
that were not treated. The treatment did not affect the final moisture content
of crisps. A linear oil–moisture relationship of samples during frying was
obtained. The effect of pre-drying followed by sugar dipping on color scores of
potato crisps, and the kinetics of the color changes were also evaluated. The
potato crisps with dipping had more shrinkage compared with the non-dipping
ones. What has emerged is that the pre-drying and subsequent sugar dipping is
an effective technique for reducing the oil contents of potato crisps. Soaking
in NaCl can also decrease fat content and improve the quality of French-fries
though rather salty taste is expected. Effect of osmotic dehydration pretreatment on
quality of French fries, used osmotic dehydration as a pre-treatment to
produce low-fat French fries where potato strips were immersed into different
solutions, which are sugar (40% w/w), NaCl, maltodextrine 12 and maltodextrine
21, for 3 h before frying(Ref.5).

Introduction:
This Challenge is looking for an additive, or other
method to reduce the fat content of a vegetable substrate fried in sunflower
oil. The process or technology should not influence the taste, odor, or texture
of the seasoning or the finished food product.
Potato tubers were stored in
darkness at about 10 °C with a relative humidity of 60%. Potatoes were
taken out of storage 12 h before frying to allow to let them reach room
temperature and for the reducing sugar contents to decrease . The potatoes were
washed, peeled and sliced with the flat ridge cutter. A 40 cm cylinder was cut from the centre
region of the slices with 2 mm thickness. To minimize enzymatic browning,
slices were blanched 5 min in an 80 °C thermostatically-controlled
stirred water bath and then cooled down to 25 °C. A single layer of
blanched potato slices was placed on stainless steel trays, which were covered
with aluminum foil, and then dried in a convection oven at a temperature of
60 °C to approximately 60% of their initial weight (a flow diagram of the
procedures is shown in Fig. 1)(Ref.5)


















Fig. 1. Potato
pre-treatment and frying processes(Ref.5).


Also with preference to Fig. 1, after air drying, the potato slices
were left to cool down to ambient conditions for 1 h. Slices were
individually dipped in 23.1 wt% sugar solution for 2 s. The sugar
solution was prepared with boiling water that had been cooled to ambient
temperature 1 h before being made into sugar solution (to prevent
microorganism contamination). After dipping, about 100 g of slices were
submerged in 3 l of canola oil in an immersion fryer (Kambrook 6 l
Deep Fryer, Kmart, Auckland, New Zealand) at 180 °C. To optimize the heat
diffusion, a Citence Type KQPS/29 Mixer (Griffen & George Limited, Great
Britain) was placed in the fryer and set at 250 rpm. During frying, 10
slices were removed every minute for 6 min. After frying, samples were
wrapped on absorbing tissue paper for 5 min prior to testing. This was done to minimize the absorption of oil due to the
cooling down period, when most of the oil content of potatoes is affected by
this process. Southern,
2000 Southern, C. R. (2000). Heat and mass transfer in the potato crisp
frying process. PhD thesis, Department of Chemical and Materials
Engineering, The University of Auckland, New Zealand. In relation to this issue, also declared that
oil uptake was a post-frying phenomenon, where surface oil was absorbed during
the cooling of the crisp; with little or no oil absorbed during frying (Ref.5)
Results
and Discussion:
There was a significant difference (P < 0.05)
between the final oil contents of pre-dried and sugar dipped and the control
samples (Fig. 2).
The oil content was, dependent on the frying time. The pre-dried and dipped
samples had lower oil contents compared with the untreated samples (the
control) and pre-dried samples. On average, 0.05 g of sugar was added to
each potato slice after dipping. To calculate the amount of sugar attached into
each potato slice, the weights of potato slice before and after dipping were
determined. The difference in weight of the potato slice before and after
dipping was the weight of sugar solution added into each slice. With the
concentration of sugar solution being 23.07 wt%, the amount of sugar added
in each slice of potato was calculated. On average, after dipping, the
percentage of sugar increased to about 3% on wet basis with pre-dried potatoes;
compared with fresh potatoes without pre-drying, the increase is only about 2%
on wet basis. The sugar addition may induce a higher specific gravity or high
solids thus leaving less space for oil uptake. In order to establish whether
the sugar-dipping affects much of the oil content or not, separate experiments
which are pre-dried non-dipping and pre-dried with sugar dipping were carried
out on the crisps. The results show that there was a significant reduction in
oil content of pre-dried and dipping compared with pre-dried and non-dipping
(as well as with the control samples). Oil reduction of 30% was obtained in this
research study. This is a considerable reduction compared with previous
techniques. For example, the NaCl soaking method only had 22.2% reduction in
oil content. This indicates that effect of sugar solution on the pre-treated
samples is not a simple additive effect on the solids density which effects the
oil uptake (Ref.5).




Fig. 2. Effect of pre-drying followed
by sugar dipping on the oil content of potato crisps during frying process
(Ref.5).
The moisture content of raw potato slices varies between 75% and 85%, depending on the environmental growing conditions and varieties.
When potato slices are fried in oil at a high temperature, the moisture would
boil explosively. This may result in cell wall bursting and damages, and
consequently, the formation of capillary holes and voids. Oil adheres to the
surfaces of the chips and is also absorbed into the pores or the voids in the
porous slices. This is particularly pronounced if the chips which just leave
the frying oil are exposed to the atmosphere, and cooled creating a vacuum
within. For these reasons, regular potato chips can have high oil contents,
ranging from 35% to 39%, and even as high as 42%. This mass transfer process has been characterized
by the movement of oil into the product and water, in the form of vapor, from
the product. The relationship of oil uptake and moisture loss of the
thin crisps during immersion frying has been studied previously by. A linear
moisture–oil relationship reported for crisps) was also obtained in this study
(see Fig. 3). The data have also demonstrated that the
initial moisture content (85.5 ± 1 wt%) and the final oil
content of control samples (37 ± 4 wt%) are in the range shown
by. Lee
et al., 1988 Lee, Y., Bretch, E. E., Bath, C. K., & Merritt, C. G.
(1988). Process for preparing low oil potato chips. United States Patent,
Patent number: 4,721,625. The pre-dried and then sugar-dipped crisps had
much lower oil contents than the control samples. It was found that the
pre-drying and sugar-dipping were the crucial steps in reducing the oil
content. Each of the two processes alone can not yield such a good overall
result. This means that the oil reduction did not happen when dipping without
pre-drying (data not shown) or pre-drying without dipping (Ref.5).

Fig. 3. Effect of the pre-treatment
on the relationships of oil uptake and moisture loss(Ref.5)
Potato
strips were soaked in 3, 5 or 7% NaCl solutions (25 _C)
previous to frying, to study the effect on oil uptake. Sensory responses
indicated the best texture and lowest oil uptake at 3% NaCl solution for 50
min. Soaking had no effect (P<0.05)
on color (L*, a*
and b*) or moisture loss during
deep fat frying at 180 _C. Soaking
significantly reduced oil uptake from 0.13 to 0.10 g oil/g dry matter and
increased the measured texture parameters (hardness to penetrate both crusts,
and both work and initial rigidity). Sensory acceptability was not different (P<0.05)
between the soaked product and a commercial sample. #
2002 Elsevier Science Ltd. All rights reserved(Ref.6).
In vacuum frying operations, food is heated under reduced
pressure(<6.67 kPa (50 Torr)) causing a reduction in the boiling point of
the oil and the moisture in the foods. It is an efficient method to produce
fruit and vegetable snacks with the necessary degree of dehydration without
excessive darkening or scorching Vacuum frying is excellent
to maintain product’s nutritional quality (phytochemicals), the color is
enhanced (less oxidation) , and it reduces oil degradation. However, a
de-oiling mechanism is necessary to remove the excessive oil absorption at the
surface of the product. Perez-Tinoco et al. (2008) produced
high quality pineapple chips by vacuum frying the fresh product at 24 kPa for
120 _C for 7 min. The chips had a golden yellow color with low oil
content
(18% w.b.), high residual content of vitamin C, presence of
phenolic compounds, and antioxidant capacity. Ref.7 observed that mango, blue potato chips,
green beans, and sweet potato chips fried under atmospheric conditions were of
lower quality than the products fried under vacuum (1.33 kPa and 120 _C), though texture characteristics
of the fried products were not affected by the frying method. Anthocyanin (mg/100g
d.b.) of vacuum fried blue potato chips was 60%
higher. Final total carotenoids (mg/g d.b.) was higher by 18% for green
beans, 19% for mango chips, and by 51% for sweet potato chips. Sensory
panelists overwhelmingly preferred (P < 0.05) the vacuum fried products for color, texture, taste,
and overall quality. Most of the products retained or accentuated their
original colors
when fried under vacuum.
The traditional fried products showed
excessive darkening and scorching. Ref.7 used paper towels to remove the
excess of oil at the surface of potato chips after the product was
removed
from the fryer. They concluded that vacuum frying (_3.12 kPa) could produce potato
chips with lower oil content (30% less) and the same texture and color
characteristics of those fried in conventional (atmospheric) fryers. They
observed that one major difference between potato slices fried under vacuum and
atmospheric conditions was the surface structure of the potato chips formed
during the process. A vacuum fried potato chips had less expansion and the
surface had numerous small bubbles, as opposed to a potato chips fried under
atmospheric pressure(Ref.7)
Fig. 4. The lab-scale
vacuum frying equipment with the de-oiling mechanism.(Ref.7


Vacuum
frying was tested as an alternative technique to develop low oil content potato
chips. The effect of oil temperature (118, 132, 144 _C)
and vacuum pressure (16.661, 9.888, and 3.115 kPa) on the drying rate and oil
absorption of potato chips and on the product quality attributes such as
shrinkage, color, and texture was investigated. Furthermore, the
characteristics of the vacuumfried
potato
chips (3.115 kPa and 144 _C)
were compared to potato chips fried under atmospheric conditions (165 _C).
During vacuum frying, oil temperature and vacuum pressure had a significant
effect on the drying rate and oil absorption rate of potato chips. Potato chips
fried at lower vacuum pressure and higher temperature had less volume
shrinkage. Color was not significantly affected by the oil temperature and
vacuum pressure. Hardness values increased with increasing oil temperature and decreasing
vacuum levels. Potato chips fried under vacuum (3.115 kPa and 144 _C)
had more volume shrinkage, were slightly softer, and lighter in color than the
potato chips fried under atmospheric conditions (165 _C).
It was concluded that vacuum frying is a process that could be a feasible
alternative to produce potato chips with lower oil content and desirable color
and texture(Ref.8).

Fig. 5 Schematic of the vacuum frying
system(Ref.8).



Fig.
6. Flow diagram of the vacuum frying process(Ref.8)..




Recommendation:

I recommend vacuum frying. The main purpose of using vacuum
frying in this study was to evaluate its feasibility for production of low
oil content potato chips.Oil absorption rate during vacuum frying of
potato chips was related to the moisture loss rate. The highest drying
loss rate (thus the highest the oil absorption rate) was obtained with the
highest oil temperature (Toil
= 144_C)
and lowest vacuum pressure (Pvac
= 3:115
kPa). The fryer operating conditions did not affect the final oil content
of the vacuum-fried chips. However, results showed that the faster the
water loss rate, the higher the oil adhesion at the chips surface and then
the higher oil absorption. In addition, as the percentage of free water is
depleted in the product, less oil is absorbed. The pressurization step
plays an important role in reducing the oil absorption during vacuum frying
(Ref.7, and 8). Vacuum frying
is a dehydration process that produces healthy fruit snacks which
partially preserve the fruit's original colour and nutritional compounds
and have a high hydrophilic antioxidant capacity(Ref.9,and 10).
I recommend
judicious blending for cereals and legumes such as chickpea, cowpea, green
gram, black gram, rice, wheat and amaranth revealed that Low-Fat fried
snacks could be prepared from a blend of 64 : 16 : 20 of cowpea : chickpea
: green gram flours. The blend had 27.8% lower fat content as compared to
the control prepared from chickpea flour alone(Ref.1, 3, and 4).
I recommend A
single layer of blanched potato slices is placed on stainless steel trays,
which are covered with aluminum foil, and then dried in a convection oven
at a temperature of 60 °C to approximately 60% of their initial
weight(Fig.1), this is for drying, the dipping before drying in sugar
solution or3,or 5, or7%NaCl solution for one hour approximately, produces about 35% reduction of oil as
described in references 5 and 6(Ref.5, and 6). Go to figures,1,2,3.4.5.
and 6. And references,1,2,3,4,5,6,7,8,9, and 10.

References:
1. Low Fat Snacks From Judicious blending of Cereal
and Legumes, by Uday S. Annapure, et al., International Journal of Food
Sciences and Nutrition, Vol.49, pp 309-314 (1998).
2. Effect of barley incorporation in bread on its
quality and glycemic responses in diabetics, by Asna Urooj, et al.,
International Journal of Food Science and Nutrition, Vol. 49 pp 265-270 (1998).
3. Influence of Legume blends on fried papad
quality by, Sunita J. Patil, et al., International Journal of Food Science and
Nutrition, Vol.51, pp 381-388 (2000).
4. Fat reduction affects quality ofakara (fried
cowpea paste),by Sara P. Patterson, R. Dixon Phillips, et al., International
Journal of Food Science and Technology, Vol. 39 pp 681-689 (2004).
5. Reducing Oil Content of Fried Potato Crisps
Considerably Using a Sweet pre-treatment Technique, by T.T. Mai Tran, Journal
of Food Engineering, Vol.80, Issue2 pp719-726 (2007).
6. NaCl Soaking Treatment for Imroving The Quality
of Fresh-Fried Potatoes, by Andrea Bunger, et al., Food Research Vol.36 pp
161-166 (2003).
7. The effect of a de-oiling mechanism on
production of high quality vacuum fried potato chips by, Rosana G. Moreira, et
al. Journal of Food Engineering, Vol.92 pp 297-304 (2009).
8. Vacuum Frying of Potato Chips, by Jagoba Gouryo,
et al., Journal of Food Engineering Vol. 55, pp 181-191 (2002).
9. Effect of Vacuum Frying on main physicochemical
and nutritional quality parameters of pineapple chips, by Maria Rosalba
Perez-Tinoco, et al. Journal of the Science of Food and Agriculture, Vol., 88
Issue6 pp945-953 (2008).
Sorption Isotherms of Vacuum-Fried Carrot Chips by, Fan Liu-Ping, et
al., Drying Technolo