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Analysis Of Frying Process Of Fried Food

Jan 22, 2019

During the frying process, intense chemical and physical changes take place in the oil.From the generation and decomposition of hydroperoxides, volatile compounds such as saturated and unsaturated aldehydes, ketones, hydrocarbons, lactones, alcohols, acids and esters are produced.Because the heat and oxidation of free radicals produce dimer and poly-acid and dimer and poly-glycerol, the viscosity of frying oil is significantly increased as a result of the polymerization.Three hydrolysis acylglycerol generate free fatty acids, these changes make the oil viscosity and free fatty acid content increased, colour and lustre is dim, surface tension, the refractive index changes, bubble tended to increase, therefore, in the process of Fried medium oil and food are great physical and chemical changes have taken place, there are some changes with the sensory quality of Fried products expected, some change is harmful.


For example, the excessive decomposition of oil will destroy the nutrition and sensory quality of Fried food, which must be strictly controlled.The chemical and physical changes of these Fried fats are affected by various frying parameters.The study on the safety evaluation of refried oil has become the focus of foreign scholars.Shyi-liangshyuetal etal. (1998) studied the stability of oil after repeated vacuum frying of radish, and pointed out the difference in stability of different kinds of oil in the process of vacuum frying at low temperature, and the method for rapid detection of acid value, peroxide value, carbonyl value and polar components of oil.The experiment shows that compared with normal pressure frying, vacuum frying oil has a lower rate of oxidative degradation. In the early stage of frying, soybean oil has a similar oxidative stability with lard and palm oil, but after frying for 24 hours, it is rapidly degraded.