ABSTRACT
Frying, a very old unit operation, is increasingly used worldwide in fast food outlets and at home, which has led to concerns about its health implications. Frying is a food unit operation in which the liquid transferring heat is hydrophobic, yet becomes part of the food. Deep-fat frying consists of immersion of food pieces in hot vegetable oil. Immersed frying or deep-frying is a common multi-functional unit operation for fast frying, texturing and cooking of foods. For decades, consumers have desired fried foods because of their unique combination of flavour, colour and texture. The mechanism of oil uptake has been studied primarily to understand the phenomenon and to develop the know-how and means to reduce the final oil content. During frying, chemical, physical and microstructural transformations of raw food material tissue are also induced (vegetable or animal). Frying induces significant microstructural changes that can be understood by using different modern visualization techniques.
