| Milk was recognized as the"nearest perfect food"by the nutrition industry and was rich in six major nutrients and various functional factors,which was one of the most easily digested food.Fatty acids,fat-soluble vitamins and cholesterol were mainly lipid components in milk,which were one of the major sources of energy supply in the human dietary structure and were important indicators for evaluating the nutritional quality of dairy products.There were many non-bovine milks with unique nutritional value and distinctive regional characteristics in our country,which attracted more and more researchers'attention in recent years.However,there was a lack of systematic research on its physicochemical and nutritional properties at present.In this study,representative milk samples were selected in Inner Mongolia,Xinjiang,Qinghai,Gansu,and Shaanxi and gas chromatography(GC),high performance liquid chromatography(HPLC),gas chromatography-mass(GC-MS)and other methods were used to analyze and compare the fatty acids,fat-soluble vitamins and cholesterol in the sample.The main research content was to study systematically the differences and changes of nutrient composition in non-bovine milks of different varieties,regions and before and after fermentation,in order to clarify the nutritional characteristics of different milk sources and provide reference for its development and utilization.The results were as follows:(1)Different milk sources have different levels of fat,fatty acids,V_A,V_E,and cholesterol.There was a significant difference in fat,free fatty acids,fatty acids,V_A,V_E,and cholesterol in different non-bovine milks(p<0.05).The content of fat(4.14 g/100 g)and total fatty acids(4053.66 mg/100 g)in yak milk were significantly higher than others(p<0.05),and its characteristic fatty acid was palmitic acid(C16:0).The contents of short-chain fatty acids(448.44 mg/100 g)and V_A(40.72?g/100 g)in goat milk were significantly higher than others(p<0.05),and its characteristic fatty acid was citric acid(C10:0).The content of polyunsaturated fatty acids(207 mg/100 g)in horse milk was significantly higher than others(p<0.05),and its characteristic fatty acid was linolenic acid(C18:3n3).The ratio of saturated fatty acids(SFA):monounsaturated fatty acids(MUFA):polyunsaturated fatty acids(PUFA)was 1.81:1.22:1,which close to the ideal mode of fatty acid 1:1:1,and the content of cholesterol(4.51 mg/100 g)was significantly lower than others(p<0.05).The characteristic fatty acid was palmitoleic acid(C16:1)in camel milk.(2)Geographical factors have a significant effect on the content of fatty acids and vitamin E.The content of free fatty acids and fatty acids in horse milk in Xinjiang were significantly higher than that in Inner Mongolia(p<0.05);the contents of free fatty acids and fatty acids in camel milk in Inner Mongolia were significantly higher than that in Xinjiang(p<0.05);The content of vitamin E in camel milk in Xinjiang was significantly higher that in Inner Mongolia(p<0.05).The content of free fatty acids,fatty acids and vitamin E in yak milk in Qinghai were significantly higher than that in Gansu(p<0.05).(3)The content of fatty acids and cholesterol changed significantly during the fermentation process.The content of free fatty acids and short-chain fatty acids in fermented milk was significantly higher than fresh milk(p<0.05)and the content of cholesterol was reduced.The content of total fatty acids in acid horse milk(1729.11 mg/100 g)was significantly higher than fresh horse milk(843.07 mg/100 g)(p<0.05),and the content of total fatty acids in acid camel milk(3053.62 mg/100 g)was significantly higher than fresh camel milk(2711.81 mg/100 g)(p<0.05)and the content of total fatty acids in acid yak milk(3054.86 mg/100 g)was significantly lower than fresh yak milk(4053.66 mg/100 g)(p<0.05). |
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