Study on the evaluation standard of extruded glutinous rice starch with thermostable α- amylase for making Chinese rice wine

To promote the industrial production of Chinese rice wine made by enzymatic extrudates, the first is to ensure the consistency of the raw material. That is, an evaluation standard of enzymatic extrudate should be set up. It was studied for the first time. By studying the changes of seven indexes of samples at different sites of extruder barrel and the die along the extrusion direction and making the correlation analysis to select the representative indexes. The results showed that the change trends of dextrose equivalent (DE), molecular weight distribution (MWD) and oligosaccharide composition (OC) were the same, and these indexes were more affected by mechanical force than by temperature. The ability of degradation of different zones was: conveying area < kneading area << exit of the die. There was little difference in extent of gelatinisation (GE) at the temperature where the enzyme activity was relatively high. Different from DE value, water solubility index (WSI) rose gradually. Surprisingly, DE was negatively correlated with GE, and positively correlated with oligosaccharides except DP1 and DP6, and had no significant correlation with water absorption index (WAI) and WSI. In conclusion, DE, WSI, DPD (especially DP6) could be used as a comprehensive evaluation index of enzymatic extrudates.

Automated summary

By studying the changes of various indexes of enzymatic extrudates in different zones of the extruder barrel, it was determined that DE, WSI, and DPD (especially DP6) can be used as comprehensive evaluation indexes for enzymatic extrudates. The trends of DE, WSI, and other indexes were found to be more influenced by mechanical force than temperature during the extrusion process.