Study On The Influence And Variance Of Fatty Acids Components In Goat Milk And Cow Milk Under Different Heat Processing Treatments

The milk of cow and goat, which is nutritional and full of various nutriments, is one of the indispensable ideal natural food to human health. To realize the conversion of the cow and goat milk from raw material of the agricultural and sideline products to industrial products,the thermal processing is one of the indispensable processes. Different heat-processing may lead the milk to change in different ways and with different degrees. Fatty acid is one of the important nutriments of milk, whose composition and content is changeable. It matters physical and mental health of human beings whether the fatty acid in food is taken scientifically and reasonably. At present, there is no systematical material about the fatty acid composition change of milk products in different thermal processing conditions, especially for the goat milk processing research. With the growing importance attached to the nutrition and health, it is more important to do research about scientific and reasonable industrial parameters.This research use GC to analyze and compare the composition and content of fatty acid after methyl-esterificating cow and goat milk sample in different thermal processing ways,systematically discussing, analyzing and valuing the influence of fatty acid composition and content of different thermal processing ways, which provides reference to produce different milk products in practice. The main conclusions are as follows:1. For the goat milk processing, under the condition of 85℃±1℃, short chain fatty acid increased and long chain fatty acid decreased with prolonging the time. For heating 30 s,linoleic acid is maximum and the content is 3.16±0.02%, the ratio of saturated fatty acids,single unsaturated fatty acids and polyunsaturated fatty acids(SFA:MUFA:PUFA) is18.55:6.10:1, which is closest to the ideal model. Therefore, in order to maximize the preservation of the fatty acids in goat milk nutritional value, taking 85℃±1℃, 30 s as the goat milk pasteurized milk sterilization process parameters is relatively scientific.2. Maintaining the constant time under the condition of ultra high temperature(T≥128℃),polyunsaturated fatty acid reduced, otherwise, short and medium chain fatty acids increased with the increase of the heating temperature. The ratio of three kinds of fatty acids is best forheating at 128 ℃, under high temperature, the ratio of three kinds of fatty acids is closed to the ideal model with shortening the heating time. As a result, in order to maximize the preservation of the fatty acids in goat milk nutrition value, taking 128℃, 4s as ultra high temperature sterilization process parameters is more scientific and reasonable.3. For the cow milk, under the condition of 85℃±1℃, short chain fatty acid increased and long chain fatty acid decreased with prolonging the heating time. For heating 30 s,linoleic acid is maximum and the content is 3.47±0.01%, the ratio of saturated fatty acids,single unsaturated fatty acids and polyunsaturated fatty acids(SFA:MUFA:PUFA) is closed in the heating time of 15 s, 30 s and 40 s, changing a bit. Consequently, in actual production, the heating time of pasteurized milk sterilization process can be chosen between 15~45s according to the need.4. Maintaining the constant time under the condition of ultra high temperature(T≥128℃),polyunsaturated fatty acid in milk reduced, otherwise, short and medium chain fatty acids increased with increasing the heating temperature. The ratio of three kinds of fatty acids is best for heating at 128℃, under high temperature, the ratio of three kinds of fatty acids is closed to the ideal model with shortening the heating time, so in order to maximize the preservation of the fatty acids in cow milk nutrition value, 128 ℃, the 4s is also the best industrial parameters for cow milk UHT sterilization.5. In the process of goat milk powder production, after being treated with the different concentration technology, fatty acid content of each component in the goat milk has also changed. Experiments revealed that polyunsaturated fatty acids content in goat milk treated with single effect concentration process is more than that of double and triple effects concentrated ways, especially linoleic acid(C18:2) content, and the ratio of saturated fatty acids, single unsaturated fatty acids and polyunsaturated fatty acids(SFA:MUFA:PUFA) is also closest to the ideal model. Therefore, in order to maximize the preservation of goat milk powder fatty acids in the nutritional value, one effect concentrated way is the best choice in practice.