Effect of malic-lactic fermentation by indigenous lactic acid bacteria on the quality of 'Hu Tai No.11' wine

In order to study the effects of malic-lactic acid fermentation (MLF) of different lactic acids bacteria on the quality of 'Hutai No.11' wine, the changes of L-malic acid content and its effects on the basic physiochemical indexes, color, phenolics, volatile flavor substances and sensory quality of wine during MLF with Lactiplantibacillus plantarum (XJ25, XJA2) and Oenococcus oeni (SD-2a, 144-46, PreAc450) were compared, and the main volatile flavor compounds were analyzed by principal component analysis (PCA). The results showed that all the selected strains could metabolize L-malic acid (content<0.1 g/L) in 'Hutai No.11' wine to complete fermentation. The wine samples fermented by strain XJ25 had good quality, and the physiochemical indexes (pH 3.82, total acid 4.58 g/L, volatile acid 0.29 g/L) in accordance with the national standard, with small color difference (ΔE<3). The contents of total tannin, total flavonol and total tartaric acid were 123.61 mg/L, 790.50 mg/L and 81.11 mg/L, respectively. The content of aldehydes and ketones, citronellol, geraniol and other terpenes was significantly increased (P<0.05), reaching 17.77 mg/L, 4.49 mg/L and 5.55 mg/L, respectively. The wine sample had a strong floral fragrance, and the wine body had good coordination and aftertaste. Based on the main volatile flavor compounds, PCA could effectively distinguish different wine samples. The results shown that the strain XJ25 was more conducive to improving the quality of 'Hutai 11' wine.