Research Of Key Technology Of High-salt-diluted State Of Soy Sauce In Guangdong Areas By Multi-strain Fermentation

Fermented soy sauce is a kind of condiment, which originated in China and now iscommonly in the world. Chinese production of soy sauce has a history of more than2000years. The most of the soy sauce was yield by Chinese every year, but the mosttechnologically advanced country is Japan, so that, they take the main role in the internationalmarket. Currently, there are a variety of soy sauce brewing technology in China, but theprocess of High-Salt-Diluted state fermentation is mainly brewing process, which is mainlycomposed of the traditional method combined with modern bio-fermentation technology, isthe major technical to produce of high-quality soy sauce. Guangdong is one of the mainproducing areas in the eastern coastal. However, compared with Japan and other countries ofadvanced technology, currently used in the process of High-Salt-Diluted state fermentationstill exists in material utilization is low, the aroma and the taste are poorer than the Japanesesoy sauce.In this paper, starting from the present situation and problems, soy sauce in Guangdongarea as the research object, through the mutation breeding, mixed koji-making by Aspergillusoryzae and Aspergillus niger, in order to further improve the protein utilization of rawmaterials. Then exogenous add yeast and lactic acid bacteria in the middle and later periods ofthe fermentation to study their influence on flavor. The results were as follows:(1) We got a new Aspergillus oryzea named GZY01which induced mutation byultraviolet from an excellent Aspergillus oryzea, which was selected from the koji ofGuangdong soy sauce with the process of High-Salt-Diluted state fermentation. The resultshowed that per spore protease activity of the mutant was108%higher than the original strain;the neutral protease activity of bran koji reached9426.43U/g(dm), the average germinationrate reached91.58%either; the soybean koji neutral protease reached209U/g(dm), alkalineprotease activity reached159U/g(dm), acid protease activity reached101U/g(dm), cellulaseactivity reached5.3U/g(dm). It was almost no aflatoxin B1and Have a good genetic stability.(2) The resulted showed that mixed koji-making and fermentation with Aspergillusoryzae GZY01and Aspergillus niger3.350possible positive effect while it was proportionedmixing; Koji-making only by Aspergillus oryzae was mainly in the first10days to decomposeproteins in raw material; Aspergillus Niger and Aspergillus oryzae to4:1ratio mixed systemworks best, in the first30days fermentation, total nitrogen utilization reached82.21%, it was35%higher than single species, the content of amino acids nitrogen up to1.162g/100mL; itwas7.8%higher than a single species. (3) On the basis of koji-making by GZY01and Aspergillus niger As3.350complex at4:1,added Japanese fission yeast and pentose tablets cocci in different proportions when thefermentation of30days,60days and75days, to study how it influences the flavor of the soysauce. Results are as follows:○1Through the analysis of aroma components, We draw the following conclusions: In thesample, which without added Japanese fission yeast and pentose tablets cocci, the percentagecomposition of Hydrocarbons, Aldehydes and Ketones is relatively high and the percentagecomposition of Alcohols, Phenols, Organic acids, Heterocyclic compound is relatively low,and some esters composition were detected either. In the sample, which had added Japanesefission yeast and pentose tablets cocci, the percentage composition of Alcohol, Phenol,Organic acid, Heterocyclic compound increased significantly. The main aroma components inBenzene ethanol,2-methoxy phenol,3-methyl butanoic acid,2,5-dimethyl Pyrazine, etc, andit were no more Hydrocarbons, Aldehydes and Ketones. It can effectively improve the contentof esters if ensure enough long follow-up fermentation time. The result showed that there wasno obvious influence to the aroma about different proportion of Japanese fission yeast andpentose tablets cocci.○2Analysis of amino acid showed that content of amino acid in the sample of mixedkoji-making by Aspergillus oryzae and Aspergillus niger was higher than the samplekoji-making just by Aspergillus oryzae. Glutamic acid and aspartic acid were the highestcontent of the16kinds amino acid in the soy sauce, and this two are umami amino acids.Umami amino acid and bitter amino acids are the main part in all amino acids in every sample,the other taste amino acid of low content. Time of adding Japanese fission yeast and pentosetablets cocci could impact the formation of amino acid. We found that if adding Japanesefission yeast and pentose tablets cocci after60days fermentation, it was no impact, if not, itwere negative to the formation of amino acid. When after75days fermentation, adding10%Japanese fission yeast and pentose tablets cocci in proportion of3:1to the fermented soysauce, could get the highest content of amino acid in soy sauce.○3The result of analysis of other taste components showed us that the sample soy sauce,which adding10%Japanese fission yeast and pentose tablets cocci in proportion of3:1to thefermented soy sauce after75days fermentation, have the highest amino nitrogen content, thehighest total acid, soluble salt-free solids is higher, on the other side, the sample soy sauce,which koji-making only by Aspergillus oryzae, amino nitrogen content in the lowest, the lowlevel of total acid, but soluble solid content without salt but the highest. ○4Sensory evaluation results showed that adding10%Japanese fission yeast andpentose tablets cocci in proportion of1:3to the fermented soy sauce after30daysfermentation was the best one. We found that this sample of various kinds of componentcontent more coordination, neither too high nor too low, all kinds of component matching in areasonable way.