耐高温酵母对黄豆酱品质的提升

Improvement of Soybean Paste Quality by Thermotolerant Yeast

中温球拟酵母(Torulopsis versatilis)是黄豆酱发酵过程中重要的微生物,高温发酵工艺会导致中温球拟酵母无法生长,进而造成黄豆酱的品质低下。为提升黄豆酱品质,以T.versatilis为出发菌株,通过基因重组构建出具有稳定耐热性的M-7新菌株。随机扩增多态性DNA(random amplified polymorphic DNA,RAPD)的结果显示,M-7与亲本的遗传结构不同,表明基因重组成功。与T.versatilis相比,M-7在高温(37、42℃)下发酵的黄豆酱中氨基酸态氮和全氮含量最高显著提升12.20%和12.03%(P<0.05),并有效提升了黄豆酱中多种风味物质的含量、多样性和感官特性。此外,M-7产生的生物胺总量远小于欧洲食品安全局规定的1 000 mg/L限量标准,保证了黄豆酱的安全性。综上,所构建的耐高温M-7新菌株可以实现改善发酵黄豆酱品质的研究意义,具有广泛应用前景。

Medium-temperature Torulopsis versatilis is an important microorganism in soybean paste fermentation.The fermentation process under high temperature may lead to the inability of medium-temperature T.versatilis to grow,resulting in the low quality of soybean paste.To improve the quality of soybean paste,a M-7 new strain with stable thermotolerance was constructed by genome shuffling with T.versatilis as the starting strain.The results of random amplified polymorphic DNA(RAPD)showed that the genetic structure of M-7 was different from that of its parents,indicating the successful genome shuffling.As compared with T.versatilis,the content of amino acid nitrogen and total nitrogen in soybean paste fermented by M-7 at high temperature(37 ℃ and 42 ℃)were significantly increased by 12.20% and 12.03%(P<0.05),respectively.M-7 effectively improved the relative content and diversity of various flavor compounds and sensory characteristics of soybean paste.In addition,the total content of biogenic amines produced by M-7 was less than 1 000 mg/L stipulated by the European Food Safety Authority,which ensured the safety of soybean paste.Overall,the thermotolerant M-7 new strain could significantly improve the quality of soybean paste and had a wide application prospect.