| In this paper,the fat of different parts of Xinjiang Kazakh sheep were taken as objects.The physical and chemical properties,fatty acid composition and volatile components differences were studied.The effects of different temperature conditions on iodine value,melting point and fatty acid of the extraction products were investigated.By adding Kazakh sheep fat in different parts of feed,the mice’s signs and blood indexes were studied.The following are the main results:(1)The physical and chemical properties,fatty acids and volatile substances of the tail fat,perirenal fat and omentum fat of Kazakh sheep in Xinjiang were analyzed by gas chromatography-mass spectrometry(GC/MS).The results showed that the physical and chemical properties of fat were different.The melting point of tail fat was significantly lower than that of perirenal fat and omental fat(P<0.05),while the iodine value of tail fat was significantly higher than that of perirenal fat and omental fat(P<0.05).A total of 20 fatty acids were detected in tail fat,while 17 fatty acids were detected in perirenal fat and omental fat.C20:5n-3c(EPA)plays a positive role in body fat in tail fat.The content of saturated fatty acid(saturated fatty acid,SFA)in the tail fat was 49.09%,which was significantly lower than the content of perirenal fat and omentum fat(59.44%,64%)(P<0.05).The content of SFA in tail fat was the highest in palmitic acid(C16:0),and the content of stearic acid(C18:0)in perirenal fat and omental fat was the highest.The content of unsaturated fatty acids in tail fat was 50.48%,which was significantly higher than that in perirenal fat and omental fat(38.95%,35.15%)(P<0.05).The content of UFA in different parts of fat was the highest in oleic acid(C18:1n-9c).A total of 33 volatile substances were detected in tail fat,9 and 7 more than those in the perirenal fat and in the omental fat.While among the volatile compounds in tail fat,(E)-2-eleven enal and 2,6-two methyl eleven acid methyl ester were the key components of aroma compounds,which showed that the tail fat is more rich in aroma components.(2)Acetone solvent was used to improve the fat content of different parts of Xinjiang Kazakh sheep.The results showed that in the solvent extraction fractions,the fat yield of different parts was the highest at17℃,and the yield of liquid fat at 2℃ was the lowest.The melting point of different parts of the fat decreased significantly with the decrease of the extraction temperature(P<0.05),while the iodine value increased significantly(P<0.05).The content of fatty acids in fat fractions of different parts was the same,among which the saturated fatty acids(SFA)of the sub fractions decreased with the decreasing of the extraction temperature,while the change of unsaturated fatty acids(UFA)was opposite to that of SFA.The content of saturated fatty acids in omental fat and perirenal fat at 37℃was higher than that in the solid fat fraction,while the content of unsaturated fatty acids in the tail fat at 2℃ was the highest.The fatty acids in SFA were more pronounced palmitic acid(C16:0)and stearic acid(C18:0),while the more obvious fatty acids in UFA were oleic acid(C18:1n-9c).Considering the content of unsaturated fatty acids,the food health of the Kazak sheep tail fat treatment group at 2℃ was better,and it had the excellent characteristics of low melting point and high unsaturated fatty acid(58.89%)at 16.87℃.(3)By adding different parts of Kazakh fat in the diet,the growth performance,the organ coefficient,the serum and liver indexes of mice were measured,and the health of Kazakh fat intake in mice was preliminarily studied.The results showed that with the dosage of tail fat,perirenal fat and omentum fat from 5 mg～20 mg,the weight of mice increased,the organ index increased,the HDL-C value of serum and liver decreased,and the value of LDL-C,TC and TG increased.These elevated blood indexes would raise the risk of coronary heart disease and atherosclerosis.The apparent digestibility of crude fat,crude ash and crude protein decreased in mice.The effects of tail fat on body weight and blood lipid in mice were less than that of omental fat and perirenal fat,which indicated that the adverse effects of tail fat intake on mice were minimal. |
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