Study On Isolation And Selection Of Yeast For Persimmon Wine And Its Application

Based on the brewing characteristics of wine, the present work focused on the improvement of aroma of persimmon wine. Two yeasts were isolated and selected from natural environment. Furthermore, the selected yeasts were used to improve the fermentation technique so that the aroma can be increased. The results are as follows.The different temperatures, pH value, culture media and concentration of ethanol were chosen as the enrichment conditions. 122 yeasts had been isolated from soil in persimmon orchard and all kinds of fruit peel.The fermentation capacity, tolerance to SO₂ and ethanol were used as selective conditions to select the yeast. During the selection, the sensory remark was emphasized. According to the aboverequirements, two strains of yeast were selected.The two yeasts were identified as Torulaspora delbrueckii, Kluyveromyces marxianus, and named as GS-7, GS-3, respectively.The biological properties of selected yeasts were analyzed in the paper. By comparison, we can see that the temperature had been more influential on the growth curve and the fermentation curve than the any other factors.The optimum growth temperatures were determined as 36℃, 34℃, and the optimum fermentation temperatures of them were all 30℃.The optimum pH values of GS-7 and GS-3 were 4.5,5.5. Among the biological properties, the flocculent property is very good, and their values can reach 2.4, 3.6, respectively.The mixed fermentation experiments were carried out in several ways. The results showed that the persimmon wine fermented by mixed cultures can not only keep the aroma of persimmon fruit, but also had a high fermentation degree. Thus, it is a hopeful way to satisfy the industrialized production of persimmon wine.