Heating and frying studies
Heating and frying was done under controlled condition using a laboratory scale deep-fat fryer (Dormeyer, model DF3CH,
Chicago, USA) filled with 2 l of oil. The oil was kept at preselected temperature (173 ± 5 ◦C) and measured by a thermocouple (T-type) using digital temperature indicator (Hitech, Bangalore, India) connected to a personal computer. The heating or frying was carried outin intermittent mode. Five batches of heating or frying (each 3min) were conducted in a day without any time lag, which was referred as heating/frying cycles. This exercise was repeated for 6 consecutive days. For each
frying experiment, 6 pooris were taken for each batch. After
each cycle, the fryer was put off and heated oil was allowed
to cool to ambient temperature (25 ± 1 ◦C). The sample was
drawn every day and stored in a brown bottle in refrigerator
for further analysis.