| Soy sauce is a Chinese traditional condiment, for a long time, soy sauce is justconsidered as a condiment. With the improvement of people’s living standard, soysauce should have the functional and healthy functions. However in current market,there is seldom healthy soy sauce product. Spirulina, which is rich in protein andvarious bioactive substances, not only can be used as protein material during brewingsoy sauce, but also can improve the healthy function of soy sauce, therefore, thedevelopment of spirulina soy sauce has certain economic and research value. Thispaper studies on the characters of enzyme system of single strain during koji making,and influential factors in koji-making, based on this, the production process ofspirulina soy sauce was studied, which can provide a reference for the massproduction of high quality spirulina soy sauce. The research contents and conclusionsof this thesis are as follows:(1) The characters of enzyme system of single strain were studied during kojimaking by considering the activity of neutral, acidic and alkaline proteinase, aminopeptidase, amylase and cellulase. It was found that enzyme system of Aspergillusoryzae3.042was more abundant, in addition to the activity of ACP which wasrelatively low; the other enzymes detected had high activity which was higher thanAspergillus C; Aspergillus niger3.350had strong ability to produce acidic protease,amylase and cellulase, while the neutral and alkaline proteinase were less.(2) Aspergillus oryzae3.042was used for koji-making. The relationshipsbetween the enzyme activity of koji with the ratio of raw materials, water amount,steaming time, and koji-making temperature were researched experimentally. Theresults show that: The ratio of raw materials can affect the nutrition and aeration of culture mediumwhich can affect the growth of Aspergillus. In this experiment, when the ratio ofsoybean meal and wheat bran was2:3, the activity of enzyme was higher; appropriatemoisture was conducive to the growth of Aspergillus, the experiment showed that theappropriate amount of water is120%; The influence of steaming time of material onkoji-making process was mainly manifested in that, moderate degeneration of theprotein was conducive to the growth of Aspergillus, excessive variability caused theenzyme activity decreased, the moderate degeneration of the protein can be reachedunder laboratory conditions of121°C, high pressure sterilization for20min. Whenkoji-making temperature is too high, it is not conducive to the accumulation ofprotease; but when koji-making temperature is too low, it is not conducive to thegrowth of Aspergillus, the experiment showed that the appropriate koji-making temperature is30°C.(3) The studies on combination strains in koji-making were carried out. It wasfound that the inhibitory effect between Aspergillus oryzae3.042and Aspergillusniger3.350was prominent, it was characterized by a significant increase of ACP inearly stage of koji-making, but then the activity of ACP was declining quickly and itwas not a significant improvement finally. Therefore, combination strains inkoji-making can not enrich the enzyme system of koji.(4) The homogenization method and ultrasonic method was used to break the cellwall of Spirulina. It was found that the best conditions for homogenization methodwere as follows: the solvent was10mmol/L CaCl2, the ratio of raw material to liquidwas1:10, the cycle times was3(2min for every time); The best conditions forultrasonic method were as follows: the solvent was10mmol/L CaCl2, the ratio of rawmaterial to liquid was1:10, the ultrasonic power was400W, the ultrasonic time was15min. The relative extraction yield of Phycocyanin was all above70%by usinghomogenization method and ultrasonic method.(5) With2%Spirulina during koji-making, no significant effect on the process ofkoji-making can be found, and all kinds of enzyme activity of the koji are as much asthose without Spirulina; the sensory organ of koji with Spirulina has something different: it is only kind of algae green, but no algae smell.(6) The method of high temperature, low temperature with multi-strains was usedfor soy sauce fermentation. It was found that the way of low temperature withmulti-strains can obtain better effect; the early low temperature can prevent thepropagation of bacteria, avoid the quick decline of pH value, which was conducive tothe work of neutral, alkaline enzyme; at the same time, the activity of enzyme can bemaintained for a long time, the content of free amino acid was relative higher, up to0.853g/100ml when fermentation was carried out for90d. As far as the product, theumami taste of soy sauce was more prominent by low temperature fermentation, andit was rich in sauce fragrance and ester fragrance, which can reach the standards ofspecial grade soy sauce. While a longer fermentation period, but low temperaturefermentation has more advantages, which can be used for Spirulina soy sauceproduction process. |
