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Study on the Improvement of the Enzyme Activity of Aspergillus Oryzae Koji and the Promotion of Fermentation Process

Author: NiHaiQing
Tutor: TaoWenYi
School: Jiangnan University
Course: Fermentation Engineering
Keywords: Additive Low-salt solid-state fermentation Protease Glucoamylase Amino nitrogen
CLC: TS264.21
Type: Master's thesis
Year: 2010
Downloads: 277
Quote: 0
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Abstract

Soy sauce is commonly used spices, a nutritious value based protein raw materials and raw materials mainly starch material brewed by microbial fermentation. Koji brewed soy sauce koji Aspergillus oryzae growth and reproduction, maximum enzyme activity and the best enzymes combination. Good or bad, the growth of Aspergillus oryzae koji process related to the strength of the protease and amylase, ultimately related to the yield and quality of soy sauce. Low-salt solid-state fermentation process short fermentation period, total nitrogen utilization and higher temperatures, but the fermentation, the yeast can not play a role, soy sauce aroma; high salt liquid fermentation of soy sauce taste delicious, fruity esters, but fermentation temperature is lower, longer fermentation period. Both processes have their advantages and disadvantages, so I hope that the combination of both fermentation process, to explore the relationship between temperature, salt content and quality of soy sauce. Based on the above-mentioned problems, the paper carried out the following three aspects: 1. Additives koji enzyme activity. External carbon sources, nitrogen sources, inorganic salts single factor experiments based on orthogonal experiment to study the neutral protease and glucoamylase activity into a song, get the best combination of: glucose dosage 0.25%, NaNO3 add the amount of 0.1%, ZnSO4 0.05% addition level. Based on this validation test results for neutral protease activity of 2383.83 U / g dry basis, glucoamylase activity 117.82 U / g dry basis, increased by 36.75% and 46.02% compared with the same batch of controlled trials. Soy sauce, low-salt solid-state fermentation with the optimization and control groups compare to the optimized group soy sauce, total nitrogen and amino nitrogen content of the quality indicators are better than the control group. Exploration of new technology, namely to explore the influence of temperature, salt content of the soy sauce. Tracking experiment measured the variation of enzyme activities in the fermentation process, amino nitrogen, total sugar, reducing sugar. The results show that: the temperature has a great influence on the activity. The low-temperature conducive to the preservation of the enzyme activity, fermentation temperature of 45 ° C for the control group, is not conducive to the preservation of the enzyme activity. However, the low-temperature will reduce the rate of the enzymatic reaction, decreased physical and chemical indicators of the fermentation process in the experimental group and soy sauce finished than the control group. Which limited increase in the amino nitrogen content of the low temperature phase at 45 ° C fermentation stage, the increase in the content of amino nitrogen obvious than before the low temperature phase. For soy sauce finished, although the total nitrogen content of the experimental group than the control group, but the amino nitrogen generation rate higher than the low temperature fermentation well so that the total nitrogen converted to the amino nitrogen. In the two-stage fermentation process exploration experiment, the total free amino acid of the 3 experimental groups compared with the control group declined. But the flavor amino acid content of 15% saline content of the experimental group compared with the control group increased by 21.42%; bitterness amino acid content than the control group was decreased by 20.12%. This shows that low temperature fermentation beneficial increase in flavor amino bitterness reduction of amino acids. The improved experimental two-stage fermentation process to determine the parameters of the new process: pre-fermented for 15 days at 45 ℃, the late 30 ℃ fermentation 10 days fermentation period of 25 days. Replaced a small powder commissioned factory original formula in wheat, in accordance with the soy sauce, fermented soybean meal: wheat bran: powder = 10:4:1 formula of raw materials, to improve the quality of soy sauce, and improving the soy sauce flavor, also can take advantage of the commissioned plant byproduct of powder, to reduce the cost of production of soy sauce.

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CLC: > Industrial Technology > Light industry,handicrafts > Food Industry > Brewing industry > Production of condiments > Commonly used spices > Soy sauce
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