摘要：Beef semitendinosus muscles were collected from ten bulls’ carcasses and used to determine fatty acids changes with different thermal treatment, boiling or microwave cooking. The results obtained show variabilities of fatty acids profiles in neutral lipid (NL), polar lipid (PL) and total lipid (TL) fraction under different internal temperature (60°C, 70°C or 80°C). Generally, in NL fraction (mainly beef intramuscular fat), content of polyunsaturated fatty acids (PUFA) increased (P < 0.05) significantly with boiling compared with raw beef, however, content of monounsaturated fatty acids (MUFA) and PUFA unchanged (P > 0.05) with the method of microwave cooking. On considering health benefit, it is proposed that beef with abundant intramuscular fat were more suitable for being treated with boiling, not microwave cooking. In PL and TL fraction, content of PUFA decreased (P < 0.05) with boiling and microwave cooking comparing with raw beef. Ratios of P/S (PUFA to saturated fatty acid (SFA)) decreased in TL with boiling or microwave cooking, whistle, ratios of M/S (MUFA to SFA) did not change under two thermal treatments in TL. Values of n-6/n-3 (n-6 PUFA to n-3 PUFA) increased significantly when beef internal temperature reached 80°C comparing with 60°C or 70°C despite being boiled or microwave cooked. Based on these observations, we considered that beef should not be over-heated when treated with boiling or microwave cooking to achieve premium ratio of n-6/n-3, the terminal core temperature of around 70°C was more appropriate.
