不同地区放牧藏羊腿肉氨基酸、脂肪酸及挥发性物质的比较分析

Comparative Analysis of Amino Acids, Fatty Acids, and Volatile Compounds in Tibetan Sheep Leg Meat from Different Grazing Regions

摘要:

为明确在不同地区放牧对藏羊腿肉中氨基酸、脂肪酸及风味的影响，实验以藏羊为研究对象，将60只藏羊分为两组，分别放牧盐碱地区和非盐碱地区的天然牧场，150 d后，分别采集两组藏羊的臂三头肌和股二头肌，测定氨基酸、脂肪酸以及挥发性风味物质。结果显示，盐碱地藏羊前腿肉中的总氨基酸含量更高，为48905.77 μmol·kg-1，而后腿肉中的总氨基酸含量更低，为29677.35 μmol·kg-1；与非盐碱地的藏羊腿肉相比，盐碱地的藏羊腿肉中的N3多不饱和脂肪酸较高而饱和脂肪酸较低；气相色谱-离子迁移谱结果表明，两组藏羊腿肉中共检测出41种挥发性成分，大部分挥发性物质在非盐碱地藏羊腿肉中含量更高；确定了庚醛单体等9种挥发性物质是两组藏羊前腿肉中的关键风味物质，3-甲基丁醇等11种挥发性物质是两组藏羊后腿肉中的关键风味物质；通过Pearson相关性发现，庚醛、己醛、1-戊醇与油酸呈正相关，2-甲基丁醛与异亮氨酸呈正相关。该研究揭示了不同地区藏羊腿肉间的差异，为盐碱地畜牧业的发展提供理论参考。

Abstract:

To clarify the effects of grazing in different regions on the amino acids, fatty acids, and flavor of Tibetan sheep leg meat, an experiment was conducted using Tibetan sheep as the research subjects. Sixty Tibetan sheep were divided into two groups, which were grazed on natural pastures in either saline-alkali or non-saline-alkali regions. After 150 d, the triceps brachii and biceps femoris muscles were collected from both groups. The amino acids, fatty acids, and volatile flavor compounds were then measured. The results showed that a higher total amino acid content was observed in the foreleg meat of Tibetan sheep grazed in saline-alkali areas (48,905.77 μmol·kg-1), while a lower content was detected in the hindleg meat (29,677.35 μmol·kg-1). Compared with the leg meat of Tibetan sheep from non-saline-alkali regions, higher levels of N3 polyunsaturated fatty acids and lower levels of saturated fatty acids were found in the leg meat of sheep from saline-alkali areas. The results of gas chromatography-ion mobility spectrometry indicated that a total of 41 volatile compounds were detected in the leg muscles of the two groups of Tibetan sheep, with most volatile substances being present in higher amounts in the leg muscles of Tibetan sheep from non-saline-alkali areas. Heptanal and nine other volatile compounds were identified as key flavor compounds in the foreleg muscles of both groups of Tibetan sheep, while 3-methylbutanol and 11 other volatile compounds were identified as key flavor compounds in the hindleg muscles of both groups of Tibetan sheep. The Pearson correlation analysis revealed that positive correlations were observed between heptanal, hexanal, 1-pentanol and oleic acid, as well as between 2-methylbutanal and isoleucine. This study has demonstrated the differences in leg meat quality of Tibetan sheep from different regions, providing theoretical references for the development of animal husbandry in saline-alkali areas.