DESIGN, DEVELOPMENT AND PERFORMANCE EVALUATION OF ELECTRIC VACUUM FRYING SYSTEM
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Date
2023-05-11
Authors
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Journal ISSN
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Publisher
ACHARYA NG RANGA AGRICULTURAL UNIVERSITY
Abstract
sectors for modern consumers with a special desire for fried snack foods. Fried products
are liked by all age groups and play an important role in consumer diets because of their
unique flavour and texture. Frying can improve the sensory quality of food by the
formation of aroma, producing attractive colour and better crispness. Frying also
inactivates enzymes, reduces the moisture content and micro-organism in foods. Frying
is a fast heating and uniform cooking method compared to other methods. Oil uptake
takes place during frying and consumption of oil poses significant health problems such
as coronary heart diseases, cancer, diabetes, and hypertension. The health concerns of
modern consumers demand healthy and tasty snack products with less oil content. In this
context, investigation on processing technologies focusing on high-quality fried products
with less oil is the need of the hour. Vacuum frying is a promising and alternative
technology to enhance the quality of fried food products due to the reduced oxidation,
reduced frying temperatures and much shorter processing times compared to atmospheric
frying. Vacuum frying is one of the frying methods that take place at below atmospheric
pressures. Vacuum frying requires specialized equipment and the design is very
sophisticated.
A vacuum fryer was designed and fabricated with a 1 mm thick SS-316 to operate
at 210 °C under 680 mm Hg vacuum level based on ASME procedures. The developed
vacuum frying system was evaluated using wheat chips at different atmospheric and
vacuum frying conditions. The atmospheric frying was done at different frying
temperatures (130, 150, 170 and 190 °C) and various frying times (3, 4.5, 6 and 7.5 min).
Vacuum frying process parameters was done using the Box-Behnken experimental design
with the three independent variables viz., frying temperature (130, 145 and 160 °C),
vacuum level (400, 500 and 600 mm Hg), and frying time (3, 4.5 and 6 min). The prepared
products at different vacuum frying and atmospheric frying conditions were subjected to
quality analysis and sensory evaluation.
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Frying temperature had shown a significant (p<0.05) effect on all the quality
attributes of atmospheric and vacuum fried wheat chips. As frying temperature increases
the moisture content of both atmospheric and vacuum fried wheat chips decreased. The
oil content of wheat chips increased with increasing frying temperature and time during
both atmospheric and vacuum frying and decreased with increasing vacuum level in
vacuum frying. The hardness of atmospheric fried wheat chips was higher compared to
vacuum fried wheat chips. Colour difference values of atmospheric fried wheat chips
decreased with increasing frying temperature and time. Optimum processing conditions
for the development of atmospheric fried chips were found as frying temperature of 156.6
°C and time of 3 min. Atmospheric fried wheat chips had an average moisture content of
3.04% (d.b.). The oil content was found to be 24.26% (d.b.). The volume expansion,
hardness and colour (ΔE) values of the chips were 837.17 mm3, 5.46 N and 23.65,
respectively. Optimum processing conditions for the development of vacuum fried wheat
chips were found as the frying temperature of 160 °C, vacuum level of 560.6 mm Hg and
time of 5.3 min. Vacuum frying produced high quality fried wheat chips compared to
atmospheric frying. The vacuum fried wheat chips had an average moisture content of
3.73% (d.b.) and oil content was found to be 18.18% (d.b.) which is good for health and
does not adversely affect the storage period. Vacuum fried wheat chips had good hardness
value of 3.97 N, which indicated the better crispiness of the fried product. The colour of
vacuum fried wheat chips was far better than atmospheric fried wheat chips. The vacuum
fried wheat chips had good acceptance among selected panellists and better quality
compared to atmospheric fried wheat chips. So, developed electric vacuum frying system
producing high quality fried chips compared to atmospheric frying.
Keywords: Wheat based snacks; vacuum technology; optimization; stress analysis; fried
snacks
Description
DESIGN, DEVELOPMENT AND
PERFORMANCE EVALUATION OF
ELECTRIC VACUUM FRYING
SYSTEM