Food Frying

Foreword

The process of deep fat frying has been in use for nearly 4000 years, and today it is one of the most popular ways to prepare food, with an increasing market worldwide. Reasons for this success are that the process is relatively cheap, fast, and easy to use, and imparts good taste and smell characteristics to the product. Although the process itself is very simple, involving immersing the product into hot oil or fat and waiting for some time, deep fat frying is an art, with many pitfalls that must be taken into consideration in order to produce high‐quality tasty products that are attractive to the consumer. In addition, the health aspect is coming more and more into focus.

The process occurring in the fryer is very complex and dynamic, with numerous different reactions taking place at the surface of the food and in the oil. Fatty acids are degraded to volatile aroma‐active compounds; triacylglycerols are cross‐linked, resulting in an increase of viscosity; the polarity of the oil changes due to degradation of triacylglycerols, inducing foaming; and the properties of the product change. The factors that make deep fat frying a complex process include not only temperature and time but also the type of fryer, oil, or food being fried, the use of additives, the amount of frying medium being used, the temperature profile, cleaning of the fryer, and the type of heat transfer employed. Even today, the interplay of these factors and the consequences for the process are not fully ...