麹菌およびセルラーゼ製剤を添加した貯蔵豆腐粕の品質

抄録

Tofu cake, a slightly pressed residual which is separated off the hot water-soluble materials from macerated and ground soybeans, was treated with Aspergillus sojae koji (1%, ASP treatment) or a cellulase preparation (50mg per kg, CEL treatment) and preserved air tightly for 30 days. At the same time, untreated tofu cake was also air tightly preserved as a control. Previously the authors (Anim. Sci. Technol. (Jpn.), 66: 79-85, 1995) showed that the two additives accelerated the lactic fermentation in preserved tofu cake. The present work aimed to analyze the acceleration effect owing to their enzyme activities by determining the NDF, ADF, WSC, pH, lactate, acetate and butyrate at 3, 7, 15 and 30 days of preservation. Enumeration of lactic acid bacteria was also carried out. The NDF in ASP treatment was significantly lower (p<0.05) compared with the control and the treatment led to a gradual increase of WSC and lactate. In the case of CEL treatment, not only NDF but also ADF decreased considerably and the accumulation of WSC and lactate was most remarkable. Changes of pH reflected characteristically the lactate concentration of three specimens in condition to preservation. Another characteristic feature was found in the viable counts of lactic bacterial number. In the CEL treated specimen, the decline in CFU number found at the final stage (30th day) of preservation indicated that there might occur ceasing of lactic acid fermentation by an excess accumulation of lactate and an extreme lowering of pH. The specimen was likely to reach a stable state substantially. On the other hand, the control specimen was obviously insufficient in both lactate concentration and lowering of pH. It was, therefore, assumed that a slight fall of CFU number found after 30 days' preservation should gives an indication that there remains a possibility for the control specimen being susceptible to unfavorable agents or microorganisms which can cause deterioration in the quality of tofu cake.