Notes
Storage temperature and quality changes of natto
2021 年 27 巻 3 号 p. 497-504
詳細
2021 年 27 巻 3 号 p. 497-504
Storage conditions significantly affect the quality of natto, a fermented soybean food produced with Bacillus subtilis (natto). We investigated the relationship between the quality of natto and the storage temperature. Manufactured natto samples were stored at 5–20 °C for 20 days, and on every 5th day we evaluated the following: 1) viable bacterial number, 2) ammonia nitrogen, 3) free amino acids, 4) gamma-polyglutamic acid (γ-PGA), 5) hardness, and 6) color of soybean grains. During storage, natto products exhibited damage, especially when stored at 20 °C. Natto products were scored based on these quality indicators, and natto stored at 5 °C for 10 days or at 10 °C for 5 days had similar quality scores. Overseas export of natto is gradually increasing. The quality score proposed in this study is a basic indicator that can be used to rule out inferior products, and this will help to grow the natto market worldwide and facilitate distribution through a cold chain.
