Fundamentals of the frying process*

Considerable interest has been developed over the years in optimizing the frying process. This approach has resulted in a better understanding of the process as a system: oil, food, fryer, and the operation in general. The frying‐process is a complex system depending on the extent of chemical reactions like oxidation, polymerisation, and hydrolysis where the physical and chemical properties of the heated fat are altering. It is difficult to estimate the extent of influence of each factor and to keep the frying conditions at an optimum level. The practical and theoretical aspects of deep‐frying such as oil‐uptake, mechanism of heat and mass‐transfer, and some analytical aspects to monitor the fat degradation are discussed. Practical applications: Deep‐frying involves close contact between the oil used and the food to be fried. The used oil becomes part of the food and contributes to the flavor, appearance, texture, shelf life, and nutritional value of the final product. A better understanding of the frying process is needed to produce fried products in a more economical way with an optimum flavor and a better shelf‐life.