Investigation Of Microbial Ferment And The Bioactivities During The Process Of Composite Bacteria Fermentation

In this paper, Aspergillus oryzae, Yeast, Streptococcus thermophilus and Lactobacillus bulgaricus were used as initial starting strain to investigate the effect of mixed fermentation of apple enzyme on sensory evaluation. Apples, pears and citrus has been used as raw materials under optimal conditions to obtain the corresponding enzyme in the supernatant enzyme for the study of the antioxidant activity of apple enzymes, enzyme activity to add species(experimental group) and not adding bacteria(control group) the comparative tests, the experimental and control groups monitoring the fermentation process of total acid, total sugar, alcohol, pH changes, in-depth study of the antioxidant activity during fermentation and enzyme activity changes of the enzyme, the experimental group and the control differences between groups. The main findings are as follows:1.The optimal combination of strains of bacteria ratio and sensory evaluationUsing sensory evaluation score level as indicator, elect to make the highest ratio of sensory evaluation scores. First, in the single-species experiments, the enzyme was sterilized after inoculation of pure strains found Aspergillus oryzae, yeast, Streptococcus thermophilus, Lactobacillus bulgaricus are on the sensory evaluation of the enzyme plays a good role. Followed by single-factor test to change the amount of a species in which the inoculation, the relation of the four kinds of different inoculum strains between sensory evaluations. Finally, the optimal ratio of strain results from the orthogonal experiment test is like this, the inoculum of Aspergillus oryzae is 1.5%, the inoculum of yeast is 1.0%, the inoculum of Streptococcus thermophilus is 1.0%, the inoculum of Lactobacillus bulgaricus is 1.0%. The highest score of sensory evaluation of enzyme up to 92.3.2.Enzymes of apple antioxidant activityTotal phenol content of enzymes in the experimental group reducing power, DPPH radical scavenging ability, hydroxyl radical scavenging, ABTS radical scavenging capacity and superoxide radical scavenging increased with concentration, the experimental group of super enzyme Apple oxygen anion radical, DPPH · radical, ABTS radical scavenging capacity than the control group; group of enzymes particularly good hydroxyl radical scavenging ability; overall, the ability of experimental group is higher than the control free radical scavenging capacity group radical scavenging ability.3. Apple enzymes, enzyme variation of pear and citrus enzyme fermentation process antioxidant activityWith the extension of the fermentation time, the changing trends of experimental and control groups both composition each antioxidant activity are different, and changes in thecomplex, depending on whether the added strain and fermentation feedstock itself. Apple,for example, add the bacteria and not added strain compared to the first 60 days of fermentation, the total phenolic content increased by 15.00%, reducing power intensity improved by 1.8%, superoxide anion radical scavenging capacity increased by 36.55%,hydroxyl radical scavenging capacity decreased 4.27%, DPPH · radical scavenging rate increased by 59%, ABTS radical scavenging capacity increased by 3.10%.4. The transformation law of Apple enzyme variation in enzyme activity during fermentationThrough the relevant enzyme activity in the experimental group and the control group detected, with the extension of the fermentation time, the enzyme activity is not showing a single incremental change laws, but increases and decreases. Add bacteria and not added strain compared to the first 90 days of fermentation, SOD activity decreased 22.39%,amylase activity increased by 50%, lipase activity decreased 69.49%, 85.71% protease activity improved, cellulose activity improved 54.19%.5.Apple enzyme fermentation process total acid, total sugar, alcohol, pH changesEnzymes within 15 days of the beginning of the fermentation, it is time to microbial growth and reproduction of the fastest, but also the total acid, total sugar, alcohol content,pH, when the greatest change. With the extension of the fermentation time, total acid content of enzymes within the presentation after the first increased and then decreased.Fermentation 15, total acid content rapid accumulation beginning, the total sugar content was significantly reduced, generating a lot of alcohol, pH value declined sharply. 15 days into the slow fermentation stage. Compared with the added strain of bacteria and the without added in the first 90 days of fermentation, the total acid content higher than24.14%, total sugar content decreased by 12.5%, the content of alcohol increased by16.67%, pH decreased by 5%.