Screening And Identification Of Milk Wine Yeast And Development Of Low-alcohol Milk Wine

This paper studied on the technology and process of low-alcohol milk. From kefir grain,natural fermented milk and the fresh soil in the dairy factory areas, two strains of yeast wereseparated and screened, which were identified as Saccharomyces cerevisiae andKluyveromyces maxianus var. lactis by formation of strains and their physiological andbiochemical characteristics. The two strains of yeast not only have propagation stability butalso give milk liquor a good flavor. Comparing the fermentation performance of the twostrains which were named as SL-3 and SL-34 with beer yeast, wine yeast etc., thefermentation product of the SL-34 had full flavor and moderate alcohol concentration, andthus SL-34 was confirmed to be used as strain of fermented milk wine.The growth synergistic effect and fermentation mode between the SL-34andLactobacillus A(Streptococcus thermophilus and Bulgarian bacteria) were also studied,Basing on experiment results, it was found that adding lactobacillus A to fermented milk isbeneficial as it improves the growth of the SL-34, hence better milk wine taste and theproduction of alcohol etc. The yeast SL-34 and the lactobacillus A have symbiotic relationshipon the nourishment. Mixed fermentation mode between the yeast SL-34 and the lactobacillusA was also determined. Addition of 8% sugar resulted in inoculation quantity of the lactic acidbacteria A was 30 mg/ L.On the condition of adding Lactobacillus A, The factors affecting fermentationtechnology such as the inoculation quantity, initial pH value, fed carbohydrates, fermentationtemperature were also studied. An orthogonal experiment was designed and the optimalformula and technology factors were as follows: milk 30%, nutriment 70mg/L, yeastinoculation quantity 1×107cfu/mL, fermentation temperature 28℃. Based on trial, 5L and200L fermentation test had been conducted, and a product line experiment was also conducted.All results showed that the fermentations were similar, i.e., the fermentation-time was 28hours, and the alcoholicity of milk wine was 2.02%(v/v), product was milky white, withwell-distributed minute foam, filling with milk fragrance and specific alcohol aroma.By sensory evaluation by expert, aroma and mouth-feel of the milk wine were better than theproducts in market, and by near thousand people tasting sample, aroma , mouth-feel ,acid/sweet degree of the fermented low alcohol milk wine acquired a good opinion of theconsumer. from gas chromatography, the aroma composition of the low alcohol milk wine ismainly ethyl acetate, acetaldehyde, 3-hydroxybutanone, alcohol, phenylethyl alcohol andisoamyl alcohol. By product quality examination and analysis, the composition was as follow,0.8% of protein, 0.79% of fat, a few vitamin A, B, D, E, and amino acid was abundant. Somilk wine has abundant nourishment;its hygienic target fit national standard ofGB16321-1996. Texture of milk wine appears very stabile after storage for six months. Itscost per ton was about 4760 RMB by calculation. So milk wine is a new-style low-milk beerwith a good market prospect.