Analysis Of Physicochemical Characteristics And Microbial Community During Strawberry Fermentation

Strawberry processing is an important way to enhance the industrial economic effectiveness with the increasing plantation area of strawberry. Developing strawberry fermentation product will break a new field for strawberry resources utilization, which will have a promising market.Fengxiang strawberry was used as raw material in this experiment, strawberry fermentation were augmented by inoculating yeast and acetic acid bacterium respectively, which were separated from strawberry spontaneous fermentation mash. During fermentation, changes of microbial diversity and physicochemical characteristics of strawberry mash were analyzed under various addition of SO2, yeast inoculation and acetic acid bacterium inoculation, the effects of operation condition on strawberry fermentation characteristics were compared. The results are as follows.1. The strawberry pulp was manufactured by the hydrolysis of0.04%(V/V) pectinase at45℃for90min, the yield of which was71.9%.2. One strain of acetic acid bacterium was isolated from strawberry spontaneous fermentation mash by transparent circle screening, which grew and produced acid well in the strawberry pulp added sodium acetate, or4%(V/V) ethanol or0.1g/L glutamate.3. During strawberry fermentation augmented by yeast under various SO2addition, yeast numbers increased at first phase and then kept stable, bacterium numbers increased at first phase and then decreased, mold numbers decreased gradually until disappeared, no acetic acid bacterium and lactobacillus was detected, SO2concentration of120mg/L was more effective to restrain bacterium and mold than other SO2concentration. Reducing sugar in strawberry fermentation mash increased at first phase and then decreased under the addition of0-120mg/L SO2, but didn’t change under the addition of higher SO2concentration, titratable acid changed a little under the addition of certain SO2concentration, but titratable acid decreased with increase of SO2concentration.4. During strawberry fermentation augmented by yeast under various inoculation, the changes of yeast and bacterium numbers were similar to that in the fermentation process under various SO2addition, mold numbers changed irregularly at first phase and then disappeared gradually, no acetic acid bacterium and lactobacillus was detected, yeast numbers increased and bacterium numbers decreased with increase of inoculation. In strawberry fermentation mash under various yeast inoculation, reducing sugar increased at first phase and then decreased, titratable acid changed a little.5. During strawberry fermentation augmented by acetic acid bacterium under various inoculation, acetic acid bacterium numbers increased at first phase and then decreased a little, yeast numbers decreased at first phase and then kept stable, and no lactobacillus, mold and other bacterium was detected, acetic acid bactenium numbers increased and yeast numbers decreased with increase of inoculation. In strawberry fermentation mash under various acetic acid bacterium inoculation, reducing sugar decreased at first phase and then kept stable, titratable acid increased at first phase and then kept stable.