| At present, about 80% soy sauce enterprises take low salt solid state fermentation technology by aspergillus oryzae in our country. Their products flavor is poor, most of them are mid-range products, which lack of competitiveness on domestic and foreign market. In order to improve the quality of products, the study based on the high salt diluted state fermentation technology, take multi strains composition by aspergillus oryzae, aspergillus Niger and monascus to mixed starter-making, and supplemently ferments with lactic acid bacteria and yeast fermentation, to enhance the flavor of soy sauce. In this research we discusses the influence on the quality and its dynamic changes of different strains’combinations in the process of making coji and fermentation, and also uses the HS-SPEM-GC-MS technique to analyze the changes of volatile component in soy sauce, therefore, we get the best combination of strains and fermentation time. The main research results are as follows:1. The sauce koji’s protease vitality and the change result of its physical and chemical indicators are:taking 3 combination groups of aspergillus oryzae, aspergillus Niger and monascus strains to mixed starter-making:group a:aspergillus oryzae; group b:the ratio of aspergillus oryzae and aspergillus Niger is 3:1; group c: the ratio of aspergillus oryzae and aspergillus Niger is 3:1, and add red yeast rice of 8% weight of the raw material. Neutral, alkalinity and acid protease activity of group b is 1810 u/g,1098 u/g and 865 u/g. Neutral protease activity and acid protease activity of group b has the strongest vitality among the three groups. On 40d contents of nitrogen amino acid of group b is higher than others, and it’s up to 1.04 g/100 ml. While group c has the highest reducing sugar content and red index respectively account for 12.2 g/100 ml and 3.1. Group b is better than other group on improve the quality of soy sauce. Group c has better reducing sugar content and red index, but reducing sugar content and red index is inadequate, so reduce weight of red yeast rice.2. The dynamic changes results of nutrient content on 9 kinds of strains fermentation sauce mash is:amino acid nitrogen content of sauce mash increased over time, before 20d the content increased rapidly. Then except of 7th group show a downward trend, others increased slowly. On 40d number 4 and number 5 in the group b are higher than other groups, the content of the amino acid nitrogen were up to 1.07 g/100 ml and 1.08g/100 ml. Total acid content of sauce mash increased over time,9th group is the largest increases and up to 1.62g/100ml on 40d, number 4 and number 5 come second both is 1.61g/100ml. Before 20d the total nitrogen content of sauce mash increased rapidly, than increased slowly. On 40d number 4 and number 5 are higher than other groups, the total nitrogen content were up to 1.73 g/100 ml and 1.72 g/100 ml.3. The results of soy sauce mash’s volatilitizable components detected by the HS-SPEM-GC-MS technology:Compare 9 kinds of combined volatilitilizable material during the process of fermentation, on 40d the 4th group is the most kinds aromatic material of soy source features and the highest relative amount, which have 37 kinds include 10 alcohol,7 acid,4 aldehyde,4 ester,3 ketone,3 phenol,6 heterocyce。Comprehensive comparative advantage the 4th group is the best strains concluded by aspergillus oryzae and aspergillus Niger starter-making, lactobacillus and yeast during the process of fermentation... |
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