Frying medium

Kita, A., Lisinska, G., and Powolny, M. (2005). The influence of frying medium degradation on fat uptake and texture of French fries. J. Sci. Food Agric. 85,1113-1118. 

Along with the reduced consunq>tion of meat products, the production of rendered animal fats has also declined. Beef tallow consumption has increased greatly since 1950 due to its distinctive flavor and stability as a frying medium. In 1985, 460,000 metric tons of beef tallow were used in the U.S. for baking and frying, but this figure was reduced to 289,000 metric tons in 1990 and is probably less this year. The decreased production of beef tallow has made it unprofitable for renderers to continue Ae processing procedures required to produce edible tallow (i). 

Refined edible beef tallow used as a deep-fat frying medium by fast-food restaurants can be subjected to conditions which are suitable for oxidation of cholesterol. Ryan et al. 

It is difficult to give an accurate definition of the perfect frying medium because there are so many applications and so many factors that affect the frying process. Some general guidelines and characteristics of a good frying oil are ... 

A deep-frying medium should be selected not only on the basis of a good Rancimat value, but also on a specified FA composition. 

To avoid polymerization, the frying medium should not contain too much linolenic acid (several countries set limits as low as 2% for linolenic acid). 

Oil penetration depends on the shape of food, its textural properties, porosity, the viscosity of the frying medium, and the temperature and duration of frying. Increased viscosity results in larger volumes of absorbed oil. Food that is high in initial fat content does not absorb oil. On the contrary, fat is leached from the food into the oil. 

Filtration can be distinguished in two types (1) absolute and (2) depth. In absolute filtration a steel or plastic screen, cartridge, or paper filter removes particles from the oil. These filters have certain porosity and most of them retain particles down to 5 pm, when used for passive filtration [72]. If diato-maceous earth or other absorbents are used, they are mixed with the oil in the fryer at the end of the day and/or shift and the suspension is pumped through the filter and circulated through the filter and back into the fryer until a filter bed is established and the fryer is free of fines and particulates. Filter media suppliers recommend a dose between 0.1% and 2.0%, by weight on the frying medium [8]. 

INFLUENCE OF THE FRYING MEDIUM ON THE STORAGE STABILITY OF THE FRIED PRODUCT... 

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