关键词: 牛肉, 脂肪酸, 大理石花纹, 肌内脂肪, 皮下脂肪

Abstract: Thirty six beef longissimus dorsi from bulls of Chinese Yellow Cattle with marbling grade of 2, 3, and 4 were used to determine fatty acids changes with different intramuscular fat content. The results obtained show a great variability in the content of water and intramuscular fat and the percentages of fatty acids. Water content and intramuscular fat content (IMF) correlated with beef marbling. In intramuscular fat and subcutaneous fat as well, 18:1cis-9, which is one of the monounsaturated fatty acids (MUFA), was the main fatty acid, followed by two saturated fatty acids (SFA), 16:0 and 18:0. The percentage of polyunsaturated fatty acids (PUFA) was relatively lower. Percentages of 16:0, 18:0 and SFA did not correlate with IMF, which showed that percentage of 16:0, 18:0 and SFA in beef longissimus dorsi were absolutely the same with subcutaneous fat. Percentages of 18:1cis-9, MUFA and ratio of M/S were positively correlated with IMF, with beef marbling increased from Grade 4 to Grade 2, percentages of 18:1cis-9 and MUFA and the ratio of M/S increased. However, percentages of 18:2cis-9,12, PUFA and n-6PUFA and the ratio of P/S, n-6/n-3 were negatively correlated with IMF, and with beef marbling increased, percentages of 18:2cis-9,11, PUFA, n-6PUFA and the ratio of P/S, n-6/n-3 decreased significantly. Composition of n-3PUFA in subcutaneous fat was lower significantly than that of beef intramuscular fat.