Abstract

The frying process is one of the most ancient procedures used to improve the sensorial properties of food. It consists of heating a vegetal oil or animal fat, where pieces of food are submerged until triggering non-enzymatic browning reactions, altering food texture, and dehydration, among other changes. This reaction also affects the fatty acids of the oil or fat, generating an oxidation process, which leads to the formation of hydroperoxides, volatile organic acids, conjugated dienes and trienes, and other primary and secondary degradation products. The presence of potentially carcinogenic substances such as acrylamide has been detected among the secondary products after oxidation during the frying process. These substances are generated when frying oil is used repeatedly for frying. Hence, it is necessary to develop a simple and accurate test in order to monitor the concentration increase of oxidation products. In this study, a new protocol to analyze polynuclear compounds was developed and used to monitor the oxidation process in frying oil. The p-Anisidine value test was used as a comparing parameter. The need to establish protocols of analysis in frying oils arises from the concern of both consumers and the industry, about the impact of recycling frying oil quality and product safety. The intention was that the protocols be reliable, simple, and economical so as to facilitate their implementation. Although there are commercial kits in the market for quality assurance of frying oil, systematic studies show difficulties in its application on a practical level with regards to repeatability and confidence. The protocol proposed has good correlation with the degree of oxidation and is an alternative to traditional procedures with the advantage of being easy to implement and having a low cost.