الفهرس 
INRODUCTIONOnly 14 pages are availabe for public view
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Abstract
Introduction
In food preservation, thermal processing considers an important treatment, especially in the manufacture of shelf stable foods with specific nutritional properties. Also, it is indispensable for determining the sensory properties, in particular color, flavor and texture in fried, baked, and roasted products. Heat treatments induces chemical change and a plethora of new molecules are generated in foods, some of which have been claimed to be health- promoting antioxidants and anti- mutagens (Studer et al., (2004).
On the other hand, the thermal processing lead to the formation of heat-induced toxic compounds, so called thermal process contaminants, that brings to bear adverse toxicological effects, create potential health risks to humans.
The frying process considers one of the most important methods for food preparation, and fried food have always been popular in many countries. In deep-frying, the food is surrounded by the frying fat. The later reacts between carbohydrate and protein with components of food, developing both odors and flavors and which appeal to consumers. (Farag & El anany, 2006).
Oils and fats have been used for food preparation since ancient times. Next to their nutritional contribution, they serve as a heat transfer medium at elevated temperatures (e.g. in frying), they improve the mouth-feel and give texture and flavor to a wide range of foodstuffs. Until the industrial revolution in the 19th century, oils and fats were purified by simple decanting and sometimes filtration. After nearly 80 years of development, the purification process changed in the 1900s to a combination of neutralization with lye, bleaching with active clay and deodorization at high temperature under vacuum with steam.
This refining process improved taste, appearance and keep ability of the product and hence allowed the use of oils and fats with a ‘natural’ strong off-taste and/or dark color like cottonseed oil, palm oil, etc. The availability of ‘purified’ oils enab