冷冻干燥与恒温干燥牦牛肉风味物质对比研究

Gas Chromatography-Mass Spectrometry Analysis of Flavor Compounds of Freeze-Dried and Thermostatically Died Yak Meat

为改善西藏牦牛肉的风味,研究干燥方式对牦牛肉风味的影响。选用固相微萃取技术富集通过不同干燥方式(冷冻干燥、常压恒温干燥)获得的牦牛肉中的风味物质,利用气相色谱-质谱仪进行分离和检测。结果表明:冷冻干燥牦牛肉中检测出138种风味物质,恒温干燥烘干的牦牛肉中检测出157种风味物质;2种干燥方式获得的牦牛肉的风味物质种类和含量均存在差异;2种牦牛肉中的主要风味物质为烃类、环烃类、酸类、芳香类、含硫化合物、醇类、酯类、醛类及酮类物质,牦牛肉风味的形成是上述风味物质综合作用的结果;2种干燥方式获得的干牦牛肉的风味物质差异主要体现在烃类、酯类和脂肪酸的含量上,与冷冻干燥相比,水煮熟后恒温干燥牛肉中烃类物质的含量减少32.50%,酯类物质增加14.29%,脂肪酸增加3.60%;冷冻干燥牛肉的主要风味物质为角鲨烯(67.66%)、庚烷(2.32%)、D-柠檬烯(2.15%)、N-棕榈酸(13.67%)、2-乙基十四烷基酯(1.70%)、油酸(2.37%)和硬脂酸(2.47%);水煮熟后恒温干燥牛肉的主要风味物质为D-柠檬烯(30.04%)、N-棕榈酸(19.30%)、十四烷基酯(5.00%)、乙醛(0.40%)和环十五烷酮(3.05%)。

The effect of drying methods on the formation of flavor compounds in yak meat was investigated in order to improve the flavor of Tibetan yak meat. The flavor compounds of freeze-dried and thermostatically dried yak meat were analyzed by solid phase microextraction coupled with gas chromatography-mass spectrometry. The results showed that a total of 138 and 157 flavor compounds were identified from freeze-dried and thermostatically dried yak meat, respectively. Both the types and amounts of flavor compounds in the meat samples, especially the amounts of esters, hydrocarbons and fatty acids were different. The major compounds that contributed to the flavor of the two samples were hydrocarbons, cyclic hydrocarbons, acids, aromatics, sulfur compounds, alcohols, esters, aldehydes and ketones. Water boiling followed by thermostatic drying decreased hydrocarbons by 32.50%, and increased esters by 14.29% and fatty acids by 3.60% compared with freeze drying. The main flavor compounds of freeze-dried yak meat were heptane （2.32%）, D-limonene （2.15%）, squalene （67.66%）, N-palmitic acid （13.67%）, 2-ethyltetmdecyl ester （1.70%）, oleic acid （2.37%） and stearic acid （2.47%）, while those of boiled and dried yak meat were D-limonene （30.04%）, N-palmitic acid （19.30%）, acetaldehyde （0.40%） and cvclooentadecanone （3.05%）.