牛肉干法成熟过程挥发性风味物质的变化规律

以干法成熟过程中牛上脑肉为研究对象，采用电子鼻和气相色谱-嗅闻-质谱联用仪研究其成熟过程中挥发性风味物质的变化规律。结果表明，不同成熟阶段牛肉风味有较好区分度；随着干法成熟时间的延长，挥发性风味物质含量显著上升，在成熟28 d时，其挥发性风味物质含量是未经成熟牛肉的3.21 倍。通过挥发性风味物质聚类分析可将干法成熟过程挥发性风味物质的变化分为3 个阶段，第1阶段为成熟7 d；第2阶段为成熟7～21 d；第3阶段为成熟21～28 d。通过相对气味活度值和香气特征分析发现，异戊醇和正己酸乙酯是整个成熟过程中的关键风味物质，呈酒香味、麦芽味和果香味。同时每个成熟时期还存在不同的关键风味物质，癸醛和十二醛在成熟28 d时被检测为关键风味物质，这使牛肉整体风味从以果香味为主，转变为以脂肪味为主。

Dynamic Changes of Volatile Compounds of Beef during the Dry-aging Process

The dynamic changes of volatile compounds in beef high rib during the dry-aging process were investigated by using electronic nose (E-nose) and gas chromatography-olfactometry-mass spectrometry (GC-O-MS). Samples with different aging periods could be clearly distinguished by E-nose. As the aging proceeded, the content of volatile compounds increased significantly. At the 28th day, the content of volatile compounds was 3.21 times as high as that of unaged beef. Cluster analysis was used to investigate the similarity of changes in volatile compounds, suggesting that the aging process could be separated into three stages. The first stage was from days 0 to 7; the second stage was from days 7 to 21; the third stage was from days 21 to 28. The analysis of relative odor activity value (ROAV) and aroma characteristics demonstrated that during the whole aging process, the key aroma compounds were isopentanol and ethyl hexanoate, with wine-like, malty and fruity flavors. Meanwhile, the key volatile compounds of beef samples varied from period to period. At the 28th day, decanal and dodecanal were identified as key aroma compounds, resulting in a change in the overall flavor of beef from fruity to fatty.