Abstract
Miso manufacturing was carried out employing two strains of Rhizopus of high protease activity and slow formation of spores, R. oryzae IFO 5418 and R. japonicus IAM 6002 selected from 6 strains employed for making tempeh and rice wine. Following results were obtained:
1. Significant differences were detected among the tested strains in the amount of spores and glucosamine when cultivated on cooked rice. The pH value of the koji (mold-cultivated rice) was lowered down to 4, acid protease with higher activity at lower pH was dominant, and amylase activity was very low.
2. Among organic acids produced by the two strains during koji making, lactic acid was highest in the amount.
3. Although the solubilized protein ratio of the Rhizopus miso was comparable to that of ordinary miso, 70%, whereas hydrolized protein ratio was only 35% of the ordinary miso, and the ratio of reducing sugar to total sugar including starch of all the misos was almost 60%.
4. On the rheological property of the Rhizopus miso, less creaminess, more coarse and harder consistency were detected in the comparison with those of ordinary miso.
5. Far higher Y (%) (C. I. E. notation on color) and less gloss than those of ordinary miso were detected.
6. Although Rhizopus miso of over 8% level of salt showed late fermentation, 4% level miso showed mild flavor with unique aroma and with out so-called over ripened flavor often detedted in odinary low salt miso.
7. Pyroglutamic acid content of Rhizopus miso was remafkably lower than that of ordinary miso.
