| Soysauce, one of the primary seasoning, has become an indispensable part in daily life. Especially recently, new species of soy sauce appear in an endless stream and reflecting market demands. So the tartary buckwheat soy sauce is very popular as a new functional condimen. However, there are lots of technical problems about fermentation process, such as poor quality, long fermentation cycle, low conversion rate, poor nutrition and function. In this paper, tartary buckwheat soy sauce’s fermented process was optimized and its quality was analyzed: ① In order to adjusting the appropriate C/N ratio,high-quality cold-pressed defatted soybean was used as raw material protease and glucoamylase in koji-making were used as the indicators. The optimizing of the process included replacement ratio of buckwheat(skin)flour to wheat bran, content of water, steaming time and koji-making time based on the orthogonal test. ②In order to increase buckwheat(skin)flour quantity, the reducing sugar and light transmittance of liquefaction as well as the reducing sugar and flavonoids content of saccharification were used as the indicators. The optimizing of syrup brine in the direct in-pool fermentation of enzymatically prepared broken buckwheat was carried out by orthogonal test.③Based on the low-salt solid tartary buckwheat soy sauce, the effect of different salt concentration and temperature were analyzed.④The volatile components in five kinds of tartary buckwheat soy sauce were comparatively analyzed by Electronic tongue and SPME-GC-MS. The results were showed as follows:1. The optimal koji-making conditions were obtained: 60% ratio of buckwheat flour to bran, 80% of water addition, 30 min of steaming time, 39 h of koji-making time. Under this condition, the neutral protease and glucoamylase activity were up to 1150.81 U/g and 1550.25 U/g, respectively.2.In the syrup brine of direct in-pool fermentation of enzymatically prepared broken buckwheat, the optimum liquefaction conditions were as follows: 50 U/g of thermostable α-amylase, 1:9.0(g/m L) ratio of materials to water, temperature of 90 ℃, 10 min for liquefaction, p H 6.5-7.0. The optimum saccharification conditions were as follows: 250 U/g of glucoamylase, temperature of 60℃, 5 h of time, p H 4.Under this condition, reducing sugar content in the saccharification liquid reached up to 13.70%, and total flavonoids content was as high as 6.95 mg/g.3. The different salt concentration and temperature were compared in the low-salt solid fermentation. The result indicated that the content of reducing sugar, amino acid nitrogen and flavonoids increased first, then, become stabilized. The content of dissoluble saltless substance and total acid increased, while, p H decreased significantly, however, sodium chloride content was stable. The quality of tartary buckwheat raw soy sauce was best when the concentration of brine was 15Bé and the temperature was 42℃-48℃-37℃. The content of the amino acid nitrogen, total acid, reducing sugar, total nitrogen and flavonoids reached to 0.625 g/100 ml, 0.656 g/100 ml, 1.023g/100 ml, 1.400g/100 ml and 1.38 mg /g, respectively.4. The principal component of PCA analyzed with TS-5000 Z Electronic tongue had good separation on five kinds of tartary buckwheat soysauce, which cumulative contribution rate was up to 87.289%. The aroma components in three kinds of tartary buckwheat soysauce were analyzed by SPME-GC-MS, including acids, alcohols, aldehydes, ketones, phenols. The raw soy sauce added in syrup, tartary buckwheat liquefied or saccharification respectively contained 33, 35, 41 kinds of volatile components. It contained pyrazines, alcohols, phenols, aldehydes, ketones, alkenes, esters, furan by the two different fermentation processes. There were twenty-six same species, mainly acetic acid, 2, 3- butanediol, guaiacol, 4- ethyl guaiacol, etc. |
PDF Full Text Request