Study on Influencing Factors of the Activity Assay for Glucoamylase of Koji

To confirm the most correct method between different analysis methods used in the activity analysis of glucoamylase of Koji, the analysis result by several methods used commonly were compared in this study. It is showed that results were quite different between different measurement methods. Glucoamylase activity in Koji by white spirit method was 36~200 u/g; it was 144.98~318.95 u/g by the method of national standard of China (GB), it was 26.96~146.67 u/g by the DSN method, it was 392.04~419 u/g by Japanese Sake Koji analysis method. It was particularly evident in the sample amount for GB; results by enzymes extraction at 30°C were greater than that at 40°C. By different enzyme extraction methods, the result show that, the activity with the extraction method in sake was greater than that with other two extraction methods of GB and DSN. By different measurement methods, but using same extraction method, the result show measurement methods in several assays had some adaptability. In shortly, glucoamylase activity by the method used in Sake was the most stable, best embodying. Activity of glucoamylase by the extraction method (by dialysis), measuring with DNS measurement method, the results were relatively stable, closest to it.