Deep-frying is a popular method of food preparation globally,
specifically in the Indian subcontinent, wherein the food is cooked
in hot fat/oil, deep enough to cover the food (Pasricha, 1989; Raina,
2001). High temperature used in frying causes lipids to undergo a
variety of chemical and physical changes due to thermal decomposition.
During deep-frying, the fat/oil is continuously exposed to
elevated temperatures in the presence of air and undergoes hydrolysis,
oxidation and polymerisation, resulting in deterioration in
quality, thereby causing changes in not only the sensory but also
the nutritional properties (Zhang, Saleh, Chen, & Shen, 2012). However,
such deteriorated fats/oils are often repeatedly used for frying