气相色谱-离子迁移谱结合化学计量学分析成熟时间对牦牛乳干酪挥发性风味物质的影响

Effect of ripening time on volatile flavor compounds of yak milk cheese based on GC-IMS and chemometrics analysis

采用气相色谱-离子迁移谱技术分析了牦牛乳干酪成熟过程中挥发性风味物质的变化。该研究共鉴定了46个信号峰中的22种挥发性风味物质。不同成熟时间牦牛乳干酪中挥发性风味物质的含量存在明显差异,成熟前期(1 d)乙偶姻和乙醇含量最高;成熟中期(30~90 d)2,4,6-三甲基吡啶、乙酸异戊酯和丁酸乙酯含量随着成熟时间的延长明显增加;成熟后期(120~180 d)丁酸乙酯、己酸乙酯二聚体、乙酸异戊酯和乙酸乙酯二聚体等含量达到最高。偏最小二乘-判别分析筛选出了12种特征挥发性标志物[变量重要性(variable important for the projection,VIP)>1],包括3-甲基-3-丁烯-1-醇、乙酸乙酯二聚体、乙偶姻、乙酸异戊酯、乙醇、丁酸乙酯、2-丁酮、正丁醇、己酸乙酯二聚体、烯丙基腈、2-戊酮和苯甲醛。主成分分析结果能够较好地区分牦牛乳干酪的成熟阶段。该研究结果可为今后牦牛乳干酪的产品开发和品质控制提供参考依据。

The changes of volatile flavor compounds in yak milk cheese during ripening were analyzed by gas chromatography-ion mobility spectrometry.The results showed that 22 volatile flavor compounds from 46 signal peaks were identified.The contents of volatile flavor compounds of yak milk cheese at different ripening time were significantly different.The contents of acetoin and ethanol were highest at the early ripening stage(1 d);the content of 2,4,6-trimethylpyridine,isoamyl acetate and ethyl butyrate increased gradually during the middle stage of ripening(30,60 and 90 d);At the late stage of ripening(120,150 and 180 d),the compounds including ethyl butyrate,ethyl hexanoate dimer,isoamyl acetate and ethyl acetate dimer increased to maximum value.Twelve potential characteristic volatile markers(VIP>1)were screened out by partial least squares-discriminant analysis,including 3-methylbut-3-en-1-ol,ethyl acetate dimer,acetoin,isoamyl acetate,ethanol,ethyl butyrate,2-butanone,n-butanol,ethyl hexanoate dimer,allyl nitrile,2-pentanone dimer and benzaldehyde were screened out.The results of principal component analysis can facilely distinguish the ripening stages of yak milk cheese.This study provides a reference for the development and quality control of yak milk cheese products in future.