Research On Characteristics Of Malolactic Fermentation By Oenococcus Oeni

Malolactic fermentation (MLF) is an important step in winemaking process, which has the properties that can decrease acidity, change color, increase bacterial stability, and so on. Oenococcus oeni is the main strain to stimulate MLF, which has a significant benefit for the wine quality. In this research, Cabernet Sauvignon and Cabernet Gernischt dry red wine were used as raw materials; HPLC, GC/MS and others were Detection Methods; conventional chemical index was determined, so were sorts and contents of amino acid and volatile components. In this way, the vinification characteristics of Oenococcus oeni Vitilactic D and 31MBR were systematically studied, and the flavor modification of MLF on dry red wine by different Oenococcus oeni strain were studied. Besides, based on Oenococcus oeni Vitilactic D, the effects on wine quality after MLF by different inoculating concentration of Oenococcus oeni were studied too. This paper focused on the following four aspects:Within the range which we set (10mg/L, 15 mg/L, 20 mg/L, 25 mg/L),with inoculating concentration increasing, rate of MLF accelerated and volatile acid and citric acid increased.Some items were analyzed in wines before and after MLF by Oenococcus oeni Vitilactic D and Oenococcus oeni 31MBR which included MLF rate, total acid, pH, rate of degrading malic acid, volatile acid content, wine anthocyanin, tannin, total phenols, flavor balance index and organic acids. We draw a conclusion that the fermentation rate of Oenococcus oeni Vitilactic D and Oenococcus oeni 31MBR were fast, the concentration of volatile acid was lower than the nation standard after MLF by Oenococcus oeni, the flavor balance index was higher than 6 after MLF by Oenococcus oeni, the ability of degrading malic acid was strong, the rate of degrading malic acid reached 80% after MLF by Oenococcus oeni.The effects of MLF by Oenococcus oeni Vitilactic D and Oenococcus oeni 31MBR to amino acid were analyzed. We found that the essential amino acid in human were significant increased after MLF by two strains. Oenococcus oeni Vitilactic D had higher increase amplitude, which in Cabernet Sauvignon and Cabernet Gernischt dry red wine can reached 115.31% and 73.58%; praline is a main amino acid in Cabernet Gernischt dry red wine, which reached 1377.8mg/L and 2022.8mg/L.The effects of MLF by Oenococcus oeni Vitilactic D and Oenococcus oeni 31MBR to volatile components were analyzed. The result suggested that the MLF by Oenococcus oeni had flavor modification effect, which increased the fruit and ester aroma of dry red wine.The nutritional value of dry red wine after MLF by Oenococcus oeni Vitilactic D and Oenococcus oeni 31MBR was increased, and better for the aroma of red wine, so the quality of wine enhanced.These results indicated that Oenococcus oeni Vitilactic D and Oenococcus oeni 31MBR had excellent characteristics of malolactic fermentation.