Preliminary Study Of Liquid Sheep Tail Fat Prepared By Water Extraction

Olive oil,peanut oil,soybean oil,rapeseed oil and other vegetable oils are the most widely used liquid oils in the market.Sheep tail fat(STF)is mainly the fat from the buttocks and tail of sheep,which has good medicinal value.However,the development of liquid STF is not perfect at present.The preparation of liquid STF helps to improve the application of STF in food processing.In this study,liquid STF was prepared by water extraction:1.In the process of STF fractionation,compared with dry fractionation,emulsion fractionation,aqueous fractionation and organic solvent fractionation,it was found that the yield of liquid STF by solvent fractionation was the highest,that by aqueous fractionation and emulsion fractionation was similar,and that by dry fractionation was the lowest.Based on the factors of economic cost and environmental impact,we chose the water agent method for subsequent experiments.2.Firstly,we optimized the influencing factors of STF fractionation by aqueous method,and found that the optimum conditions were as follows: Oil: water 7:1,cooling time 12 h,reaction temperature 20 ?,stirring at 300 rpm for 2.5 min,and centrifugation at 4500 rpm for 15 min.The yield of liquid STF was 59.73%,and its melting point was 14.33 ?,which was 9.87 ? lower than that of the original oil.Further,the liquid STF was extracted twice.Under the same conditions,the yield of liquid STF was 13.94% and the melting point was 8.47 ? which was 14.02 ?lower than that of the original oil.3.The results showed that the iodine value,acid value and peroxide value of liquid STF were 64.54 g/100 g,1.07 mg KOH / g and 0.06 g / 100 g respectively.These indexes were in line with the national standard of animal oil parameters,and better than the starting STF.GC-MS showed that the unsaturation of fatty acids in liquid STF increased,especially the content of polyunsaturated fatty acids(PUFA)increased from 58.03% to 69.53%.4.Lard and butter with high melting point were separated by water agent method.The results showed that the liquid lard with high yield could be obtained when the ratio of oil to water was 7:1,cooling time was 4 h,reaction temperature was 32 ?,stirring at800 rpm for 2.0 min and centrifugation at 4000 rpm;It was found that the optimum conditions for butter were as follows: Oil: water 1:9,cooling time 6 h,reaction temperature 30 ?,stirring at 200 rpm for 2.0 min,centrifugation at 5000 rpm.The liquid butter with high yield was obtained.The results showed that the water extraction method had certain universality in the separation of animal oil.To sum up,our results showed that the liquid STF as well as Lard and butter with low melting point can be obtained by aqueous extraction,which provides a certain research basis for the development and utilization of liquid animal fat.