大豆分离蛋白风味物质的气相色谱-质谱分析

采用顶空固相微萃取技术通过气相色谱一质谱联用分析了两种大豆分离蛋白的风味成分。在未经乙醇处理的样品中共检测到己醛等14种风味物质，而经乙醇处理的样品仅检测到5种风味物质；豆粕经乙醇处理后制备的大豆分离蛋白，主要异味成分之一——1-辛烯-3-醇未被检测到；且己醛、乙酸乙酯、1-己醇、辛酸乙酯及苯甲醛等5种风味成分的含量明显减少，不及对照样品的10％。证明经乙醇处理后的大豆分离蛋白，其风味已得到了明显的改善。

Identification of the Flavor Compounds Obtained from Two Different Types of Soybean Protein Isolates by Gas Chromatography-Mass Spectrometry

Defatted soy flakes were washed with aqueous alcohol and the resultant material was extracted with water to prepare soy protein isolate (SPI_1) with improved flavor profile in comparing with the conventional soy protein isolate (SPI_2). A gas chromatography-mass spectrometry (GC-MS) was used to identify the flavor compounds from two different types of soybean protein ~isolates by headspace solid-phase microextraction (HS-SPME). A total of fourteen volatile flavor compounds were identified from the conventional soybean protein ~isolate , and only five components were determined from the soybean protein isolate prepared with alcohol ~washing . 1-octen-3-ol, one of the main off-flavor compounds, was not found in the alcohol washed sample and the total content of the major constituents, such as hexanal, ethyl acetate, 1-hexanol, ethyl caprylate and benzaldehyde, was much lower (less than one-tenth) than that of the conventional soybean protein isolate. The ~particular alcohol selected for extraction improved the flavor profile of soybean protein isolate considerably.