Changes of related indexes of Liuyang Douchi during koji-cooling
In order to clarify the influence of the koji-cooling stage on the quality of Douchi during the Liuyang Douchi production process, the microbial quantities, physicochemical indexes and key enzyme activities at different koji-cooling times were determined. The results showed that the total colonies c...
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| Format: | Article |
| Language: | English |
| Published: |
Editorial Department of China Brewing
2024-02-01
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| Series: | Zhongguo niangzao |
| Subjects: | |
| Online Access: | https://manu61.magtech.com.cn/zgnz/fileup/0254-5071/PDF/0254-5071-2024-43-2-82.pdf |
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| Summary: | In order to clarify the influence of the koji-cooling stage on the quality of Douchi during the Liuyang Douchi production process, the microbial quantities, physicochemical indexes and key enzyme activities at different koji-cooling times were determined. The results showed that the total colonies counts and fungi counts increased gradually and reached the maximum at 96 h, which were 5.9×10<sup>9</sup> CFU/g and 7.6×10<sup>6</sup> CFU/g, respectively. The moisture content decreased to 23.80%, the total sugar contents decreased to 5.09%, while the total acid, amino acid nitrogen and glycosidic isoflavone contents increased to 1.46%, 0.88%, 1 383.90 mg/kg, respectively. Except for neutral protease, the activity of α-amylase, lipase, cellulase, acidic protease and alkaline protease all increased at first and then decreased, and the neutral protease was the main enzyme in the koji-cooling stage. The results of correlation analysis showed that during koji-cooling stage of Liuyang Douchi, there were significant positive correlation between moisture content and total colonies counts, total sugar content and total colonies counts, α-amylase and cellulase activities, and amino acid nitrogen content and neutral protease activity (P<0.05), while amino acid nitrogen content was significantly negatively correlated with moisture content (P<0.05). The results could provide theoretical basis for the process optimization of traditional Aspergillus type Douchi in Liuyang. |
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| ISSN: | 0254-5071 |