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Dynamic Analysis on Later Fermentation Process of Dou-chi Natural Fermentation

Author: SunSen
Tutor: SongJunMei
School: Shandong Institute of Light Industry
Course: Of Food Science
Keywords: Tempeh Microflora Physical and chemical indicators Key enzyme Salinity
CLC: TS214.2
Type: Master's thesis
Year: 2008
Downloads: 433
Quote: 6
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Abstract

Tempeh is a whole soybean or (watercress) as raw material, processed by soaking, cooking, koji fermentation processes, with a high nutritional value and medical value of fermented soybean food. Tempeh natural fermentation production cycle is too long, the by seasonal temperature limit can not be perennial production, a serious impact on the plant utilization, cash flow, market supply and scale, increased production costs for manufacturers. In order to control the fermentation, tempeh production industrialization, we must achieve the pure fermentation. In order to achieve pure fermentation and industrial production, the premise is to understand the relationship between the distribution of micro-organisms, and the matrix in the natural fermentation products, grasp the fermentation mechanism to determine the role of microflora in the fermentation process , then you can filter out the appropriate destination bacteria in fermented tempeh scale industrial production. But also to understand the fermentation process generated nutrients and flavor substances content and changes. Tempeh fermentation process after the physical and chemical indicators of product maturity and flavor has a great influence only the physical and chemical indicators have reached the national standard, the product to mature. Also key enzyme activity was measured in the post-fermentation process to determine their impact on the latter part of the fermentation process. This thesis through research tempeh fermentation process the microbial phase change, the impact of changes in physical and chemical indicators and key enzyme activity and salinity tempeh fermentation cycle to determine the dominant bacteria in the tempeh fermentation process by the physical and chemical indicators The trends determined after the fermentation cycle, and reduce the salinity. Change of microorganisms tempeh fermentation process tempeh fermentation process after the main role of the microorganism is a bacteria, fungi and yeasts. After six days before the fermentation, the number of micro-organisms changed greatly. The total number of bacteria by the the koji late 7.9 × 109cfu / g rapidly decreased after the sixth day of fermentation reduced to 0.085 × 106 cfu / g, the future continue to reduce, but decreased more slowly, after 15 days of fermentation the total number of bacteria Basic stabilized. Be seen by the identification of the dominant flora bacteria mainly lactic acid bacteria, lactic acid bacteria produce lactic acid and acetic acid and other organic acids. Organic acids is an important component of the tempeh flavor compounds. Tempeh after the beginning of fermentation, the yeast blooms, there is a peak. After fermentation to proceed with the accumulation of acidic metabolites and alcohol, the activity of the yeast is suppressed, so the sharp decline in the number of yeast after 7 days after fermentation, the total number of yeast substantially maintained at a relatively stable after 18 days The low number of levels. Identified yeast dominant flora Lu's yeast Saccharomyces rouxii. After the beginning of fermentation, mold growth has basically stopped and gradually disappearing, but fungal enzymes continue to play a role. The number of colonies in the counting plate medium essentially unchanged magnitude of between 102 to 103. The identified advantages flora Aspergillus oryzae. Studies have shown that the physical and chemical indicators of change in the post-fermentation process tempeh fermentation process of amino acid nitrogen content gradually increased, rapid changes in the early and late changes slowly, 21 Telsda to 0.655%, in line with national standards, and in the future its content changed little in a few days. Reducing sugar in the tempeh fermentation process change is not obvious, the change is very small, a slight increase after the start of the fermentation, but the overall downward trend. Total acid content is gradually increased, the initial increased significantly slow late last reached 1.5%. Protease activity in the post-fermentation process overall downward trend. The cellulase activity overall downward trend, with some fluctuations in the middle. After the fermentation process of adding different amount of salt tempeh, tempeh products of microbial decreased, tempeh mature time, under the premise of ensuring the quality and flavor, salt dosage of 9% with increasing salinity time short, you can reduce costs, shorten the production cycle of tempeh, and low salt content can reduce the high amount of salt on the human body.

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