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 micro-bial 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 5.9×109 CFU/g and 7.6×106 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 mois-ture content and total colonies counts,total sugar content and total colonies counts,α-amylase and cellulase activities,and amino acid nitrogen con-tent 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.
Liuyang Douchikoji-coolingmicrobial quantityenzyme activityphysicochemical index
万方数据
维普
