Processos de fritura em escala laboratorial e industrial para estabelecer procedimentos de boas práticas

Abstract

During frying by immersion of food, several physical and chemical changes in the oil may occur, influencing the products intended for consumption. The objective of the work was to evaluate the execution of the frying by immersion in laboratory and industrial scale in order to identify the flaws for improvements during the process and to elaborate a manual of good frying practices. On the laboratory scale, the batch frying process by immersion was carried out with frozen products, with different characteristics, in new soy oil and without replacement for 6 hours of heating at 180ºC. The oil was analyzed by the indexes of peroxide, acidity, iodine and saponification, viscosity and color. The products fried in this oil were also evaluated. The frying process on an industrial scale was carried out in a company that manages industrial kitchens installed in different regions of the country, through an online semi¬structured questionnaire and on-site monitoring in three units. Through the results of the laboratory analyzes, changes were observed in the peroxide, acidity, iodine and saponification indices, as well as in the oil viscosity at the end of the frying process, the color parameters adopted in the oil used for frying new changes, highlighting the luminosity which has decreased, browning of soybean oil. After 6 hours of frying, the residual oil used was still suitable for use, according to physical-determined characteristics. The potatoes and nuggets pre-fried and frozen showed changes resulting from the frying process, both decreased the moisture content and changed the color, whereas in nuggets the color difference was more intensified in the last hour frying. An analysis of the questionnaire responses identified non conformities in the frying process on an industrial scale, which were confirmed during the on-site process evaluation, such as: inadequate temperature, absence of temperature control and recording, replacement of new oil, storage and cleaning equipment, disposal of used oil, among other. The need to raise awareness and instruct supervisors and food handlers who perform the frying process was evidenced, so a manual of good frying practices and a spreadsheet for monitoring the temperature of frying oil in industrial kitchen units were elaborated, aiming at implement improvements in the process in order to operate it safely and perform the disposal of oil without financial and consumer losses.