Changes in Chemical Components during Fermentation of Highland Barley Wine with Multi-Strain Starter

The changes in chemical components of highland barley wine during fermentation with multi-strain starter were studied and compared with those of traditional fermented highland barley wine.The results showed that the dynamic change patterns of chemical components during fermentation with multi-strain starter and traditional starter were similar.pH value decreased rapidly at first and then kept stable at pH 4.0-4.3,the measured total acidity showed an increasing trend.Fermentation temperature increased first and then dropped gradually with the highest value of about 36.2 ℃.Saccharifying enzyme activity and reducing sugar content increased significantly during 0-24 h,and then decreased till the end of fermentation.Total sugar content kept decreasing throughout the whole process.The alcohol concentration fermented by multi-strain starter was 10.30% which indicated a significant(P 0.05) increase by 57.73% compared with that obtained using traditional starter.Both ammonia-N content and acid proteinase activity increased in the early stages of fermentation followed by a slow decrease.Total free amino acid(FAA) in the final product fermented by multi-strain starter was 80.923 mg/100 mL and no methionine was detected in it.Sensory evaluation showed that the optimal fermentation duration was 60-72 h for highland barley wine production by multi-strain starter.Under this condition,the product was acceptable and maintained the major flavor of wine fermented by traditional starter as evaluated by sensory evaluation.