豆腐酸浆中酵母的分离鉴定及其在酸豆乳中的应用

Isolation and Identification of Yeast from Acidic Tofu Whey and its Application to Soy Yogurt

摘要:

从豆腐酸浆水中分离出一株酵母Y，并通过形态学观察、26S rDNA序列分析及Biolog微生物鉴定系统鉴定，得出最为可能的结果为阿米塞毕赤氏酵母（Pichia amenthioninaY）。进一步的研究表明该菌株生长温度范围较宽，在26℃-42℃培养均能生长，最适生长温度为36℃。将该菌株与乳酸菌XPL-1作为复合发酵剂制备酸豆乳，采用SPME-GC-MS分析其挥发性香气成分，并对数据进行标准化和主成分分析（PCA），结果显示，酸豆乳中特征性的豆腥味成分基本消失，乙酸乙酯、乙酸辛酯、乙酸-3-甲基丁酯、苯乙醇、2，3-丁二醇等醇类、酯类香气成分丰富，其中在36℃发酵制备的酸豆乳中乙酸乙酯等香气成分含量更高，并出现了2-乙基己醇等香气成分，表明菌株Y是一株产香且脱除豆腥味能力强的高温菌，有很好的开发应用前景。

Abstract:

The yeast strain Y isolated from acidic tofu whey was identified as Pichia amenthionina Y by morphological examination, 26S ribosomal DNA sequence analysis, and by means of the Biolog microbial identification system. Further analyses indicated that this strain can grow in a wide temperature range (26 ℃~42 ℃), and that its optimal temperature is 36 ℃. Strain Y and lactic acid bacteria XPL-1 were used as combined starter culture to prepare soy yogurt,, and headspace solid phase microextraction with gas chromatography and tandem mass spectrometry (SPME-GC-MS) was employed to analyze the volatile components in the soy yogurt samples. The data were normalized and then analyzed by principal component analysis (PCA). The results indicated that the characteristic beany flavor of the soy yogurt generally disappeared, and abundant alcohol and ester aroma components were generated, including ethyl acetate, octyl acetate, isoamyl acetate, phenylethanol, and 2,3-butanediol. A higher concentration of ethyl acetate was found in the soy yogurt after fermentation at 36 ℃, in the presence of 2-ethyl hexanol and other aroma components, indicating that P. amenthionina Y is a thermophilic yeast that can produce aroma and remove the beany flavor, and has good prospects for development and practical applications.