Study On Correlations Between Strains And Qualities Of Rice Dreg Sauce And Recycling Sauce Residue

Rice dreg is a rich source of protein resources which mainly used as animal feed and it has a good application prospect for its further development and use.Preceding research has demonstrated that feasibility of rice dreg replacement of traditional soybean or soybean meal of rice dreg sauce brewing.In order to further improve the quality of rice dreg sauce and rice dreg protein utilization and enhance recycling value of sauce residure,the by-products of soy sauce,this paper has got the following conclusion:Aspergillus oryzae HN3.042,Aspergillus niger AS3.350 and Zygsoaccharomyces rouxii were applied to produce the sauce,and correlation of strains to quality of the sauce and degradation of RDP were evaluated by a series of indicators.It turned out that the contents of amino acid nitrogen(AAN),total nitrogen(TN),transformation efficiency of total nitrogen(TET),peptides with low molecular weight and flavor free amino acids(FAA)of the sauce fermented by multi-strain presented higher level than those by single-strain,AAN and TN of the sauce fermented by multi-strain for 31 days were 1.07 g/100 ml,1.33 g/100 ml respectively,which reached first grade of national standard level of brewing soy sauce,while the TET of sauce were 69.50%.Multi-strain performed an obvious enhancement on quality of rice dreg sauce.A comparative study of rice dreg sauce and soy sauce fermented by Aspergillus oryzae HN3.042.On the basis of optimized conditions from preliminary experiments,the production regularity of neutral,alkaline and acid protease during koji making and the dynamic change of amino nitrogen,total nitrogen,soluble protein,soluble saltless solid and protein utilization rate were studied comparatively,and the sauces were graded by sensory evaluation,and GC-MS with solid phase microextraction(SPME)was applied to analyze and compare their volatile aromatic substances.The studies showed that contents of amino nitrogen and total nitrogen in sauce mash from rice dreg were always higher than that from soybean,while the soluble protein and saltless solids were lower than soybean.Protein utilization rate of soy sauce reached 75.28%,higher than 66.85% of rice dreg sauce at 31 days of fermentation.The total score of soy sauce in sensory evaluation was slightly higher than that of rice dreg sauce and the difference of substances such as alcohols,esters,acids,and pyrazine was obvious.A preliminary research was applied to enzymatic hydrolysis technology of sauce residue.To determine the best condition of alkaline and neutral protease enzymolysis were temperature 55?,enzyme amount 7000 u/g,pH 10.0,solid-liquid ratio 1:15,enzymolysis time 4 h and pH 7.0,temperature 50?,enzyme amount 8000 u/g,solid-liquid ratio 1:15 respectively.The hydrolysis degree of sauce residue was greatly improved,up to 16.53%.The recycle of sauce residue enzyme solution was studied,on the basis of addition amount of 20%,using enzymatic hydrolysis sauce residue and rice dreg to make koji and fermentation,found that there was a influence on the hydrolysis degree and protease activity in koji-making stage and amino acid nitrogen,total nitrogen,color rate,red index and total nitrogen utilization in fermentation stage with different sauce residue enzyme solution way.