Study On Non-Alcoholic Beverage Similar To Beer With Aroma-Producing Strains Of Geotrichum Candidum

The policy of national wine is changing, that is, high-alcohol drinks are changing to low-alcohol drinks, commom drinks are changing to quality drinks, distilled drinks are changing to brewing drinks, grain liquor are changing to fruit-wine. Because Non-Alcoholic Beverage Similar to Beer were accordant with the trend of low-alcohol and health, it were seen as health drinks for 21st century.In this paper, we studied on the screening and identification of strains, and fermented processing of Non-Alcoholic Beverage Similar to Beer. Seven excellent strains GS7C,GS28B,GS38D,XJ45B,XJ58A,SX71A and SX70B were screened out from 29 strains which were separated from the Chinese northwest region,were finally identified as Galactomyces geotrichum based on morphology, 26S rDNA Dl/D2 and ITS domain sequence analysis.The seven strains not only perform their genetic stability, but also produce a good fruit-aroma of fermented broth. By comparing the fermentation performance and sensory evaluation among them, the fermentation products of GS28B,SX71A have better flavor and were used as strains of fermented Non-Alcoholic Beverage Similar to Beer.By detecting the OD and the dry weight of cell, the growth curves of GS28B,SX71A were determined. By the optimization of single-factor,four key factors, sunch as temperature,inoculum concentration,rotation speed,protein content(TN) were optimized. Then fermentative process was optimized by using orthogonal test. The best parameters of optimum combination of strain GS28B were 24℃, 1.0g/L protein content(TN), 160r/min rotation speed, 5.0%(v/v) inoculation rate. The best parameters of optimum combination of strain SX71A were 24℃, 1.0g/L protein content(TN), 160r/min rotation speed, 2.0%(v/v) inoculation rate. Under the optimal conditions, main volatile compounds produced in Non-Alcoholic Beverage Similar to Beer were extracted with dichloromethane and identified by GC–MS. The results of the chemical index and aroma-component analysis showed that 6 kinds of fermented aroma were produced by the GS28B, 8 kinds of fermented aroma are produced by the SX71A.They mainly include alcohols, esters. By using GC, the alcoholicity produced by GS28B and SX71A were 0.02%(v/v)and 0.03%(v/v), methanol content were 0.0001%(v/v) and 0.003%(v/v), respectived.The edible-safety were assessed the for the fermented product of Geotrichum candidum. The toxicological safety properties were examined, including experiments of acute toxicity,bone marrow cell micronucleus,sperm shape aberration test , 30 days feeding test as well. The LD50 of the fermented product of Geotrichum candidum was more than 10.0g/kg bw,which fell into the limit of non-toxidity.The results of negative test groups were observed in the genetic toxidity test of bone marrow cell micronucleus,sperm shape abnormality test.Abnormal phenomena had not been found in 30 days feeding test under the experimental dosage range of 2.5,5.0,10.0g/kg bw.Therefore the fermented product of Geotrichum candidum has a good edible-safety property for the consumers'drinking.