Study On Fermentation Technology And Aroma Component Of Milk Beer

A beverage called milk beer is made from fresh milk which is airtight sterilized. The milk beer is fermented by yeast and lactobacillus. With the need of new product, new taste, low-alcohol beverage by fermented is the current. It is satisfied of people's consumption of milk. With the development of fermented dairy product, it's of significant for geting to the bottom of process of milk product and promoting the industrial process of dairy industry.The growth curve of USA beer yeast, Angle active dry beer yeast, QingDao beer yeast, Japan beer yeast were mensurated in this experimentation. Based on sense test and compared with the fermentation performance of the four strains, the microzyme of milk beer tasted good was screened out. The fermentation product of beer yeast had good flavor .USA beer yeast was confirmend to be used as strain of fermented milk beer.On the condition of laboratory , based on mainly material of fresh milk, the factors affecting fermentation technology such as the inoculation quantity, sucrose addition quantity, fermentation temperature,initial pH value were also studied. Alcoholicity and sense test was carded out. On the basic of above, an orthogonal experiment was designed and the optimal technology factors were as follows: yeast inoculation quantity was 2×10~6个/mL, sucrose addition quantity was 8%, fermentation temperature was 30℃, fermentation time was 15 hours.The milk beer has a good flavor, alcoholicity was 0.80%～0.90%.The factors homogenating conditions which affecting milk beer's stability were studied. The homogenating conditions were confirmed: homogenation pressure was15～21MPa, homogenation temperature was 60℃. The factors such as stabilizers, emulsifiers were also studied. On the basic of above, an orthogonal experiment was designed. The result showed: the optimal formula factors were as follows: CMC addition quantity was 0.50%, xanthic acid addition quantity was 0.10%, sucrose fatty acid ester addition quantity was 0.15%, trisodium citrate addition quantity was 0.15%.Based on the above trial, 10L fermentation test had been conducted. The results showed that the fermentation time was about 15 hours. The product was ivory-white, tasty and refreshing, a harmonious blend full of milk fragrance and full-bodied alcohol aroma. The product sized up the quality request.By the analysis of Eliter---AAA, milk-beer had general and abundant amino acid. The total of amino acid was 810mg/100mL; protein was 1.00%. So milk beer has high nourishment. By the analysis of GC/MS, the primary aroma component of milk beer was ethanol, octanoic acid ethyl ester, 1-butanol-3-methyl, decanoic acid ethyl ester, hexanoic acid ethyl ester, phenylethyl alcohol, benzoic acid, ethyl acetate,and so on. The relative content of milk beer was also detected. The different fermentation time and different fermentation temperature were studied on aroma component of milk beer. The results showed that the alcoholic and the ester gradually increased, the acid gradually reduced as the temperature rising. At 30℃,15h, the alcoholic and the ester were the hightest,the acid was the least. The relative beetween aroma content of milk beer and grade was also detected. By the relativity analysis ,the component was prominence relativity such as: the alcoholic(0.934*), 1-Butanol, 3-methyl(0.921*), Acetic acid(-0.903*).