Sun Jingxian, Ge Yuzi, Gu Xiaobo, Li Ruyi, Ma Wen, Jin Gang
School of Agriculture, Ningxia University, Yinchuan 750021, China.
School of Food and Wine, Ningxia University, Yinchuan 750021, China.
Foods. 2022 Aug 15;11(16):2455. doi: 10.3390/foods11162455.
Malolactic fermentation (MLF) converts malic acid into lactic acid by lactic acid bacteria (LAB). MLF may affect potential wine quality impact as global warming intensifies, and the alcohol in the wine increases, which threatens MLF. is considered a new generation of MLF starter because of the ability of high ethanol tolerance and good enological characteristics. In this research, 132 LAB strains were isolated from the eastern foothills of Helan Mountain in Ningxia, China. Twenty-one higher ethanol tolerance isolates were obtained by 15% (/) ethanol preliminary screening. They were identified by 16S rRNA sequencing and differentiated by randomly amplified polymorphic DNA (RAPD). Stress factors include ethanol, pH, and SO, and the combination of stresses was used to screen stress-tolerance strains. β-D-glucosidase activity, MLF performance, and biogenic amine content were tested to evaluate the enological characteristics. GC-MS detected the volatile components of the wine after MLF. The results showed that twenty strains were identified as , and one strain was . Especially, the strains of A7, A18, A23, A50, and B28 showed strong resistance to high ethanol, low pH, and high SO. A7, A50, and B28 showed better β-D-glucosidase activity and thus were inoculated into cabernet sauvignon wines whose ethanol content was 14.75% (/) to proceed MLF. A7 finished MLF in 36 d, while the control strains 31-DH and BV-S2 finished MLF in 24 d and 28 d, respectively. Nevertheless, A50 and B28 did not finish MLF in 36 d. The data showed that A7 brought a more volatile aroma than control. Notably, the esters and terpenes in the wine increased. These results demonstrated the potential applicability of A7 as a new MLF starter culture, especially for high-ethanol wines.
苹果酸-乳酸发酵（MLF）是由乳酸菌（LAB）将苹果酸转化为乳酸的过程。随着全球变暖加剧以及葡萄酒中酒精含量增加，这可能会对潜在的葡萄酒品质产生影响，进而威胁到MLF。由于具有高乙醇耐受性和良好的酿酒学特性，[具体菌株名称未提及]被认为是新一代的MLF发酵剂。在本研究中，从中国宁夏贺兰山麓东部分离出132株LAB菌株。通过15%（体积分数）乙醇初步筛选获得了21株具有较高乙醇耐受性的分离株。通过16S rRNA测序对它们进行鉴定，并通过随机扩增多态性DNA（RAPD）进行区分。应激因素包括乙醇、pH值和二氧化硫，采用应激因素组合来筛选耐应激菌株。测试了β-D-葡萄糖苷酶活性、MLF性能和生物胺含量以评估酿酒学特性。气相色谱-质谱联用仪（GC-MS）检测了MLF后葡萄酒的挥发性成分。结果表明，鉴定出20株为[具体菌株名称未提及]，1株为[具体菌株名称未提及]。特别是，A7、A18、A23、A50和B28菌株对高乙醇、低pH值和高二氧化硫表现出较强的抗性。A7、A50和B28表现出较好的β-D-葡萄糖苷酶活性，因此将它们接种到乙醇含量为14.75%（体积分数）的赤霞珠葡萄酒中进行MLF。A7在36天内完成了MLF，而对照菌株31-DH和BV-S2分别在24天和28天内完成了MLF。然而，A50和B28在36天内未完成MLF。数据表明，A7带来的挥发性香气比对照更多。值得注意的是，葡萄酒中的酯类和萜类物质增加。这些结果证明了A7作为一种新型MLF发酵剂培养物的潜在适用性，特别是对于高乙醇含量的葡萄酒。
