Study On Purification And Application Of Resistant Dextrin

The resistant dextrin is a kind of soluble dietary fiber products, mainly applied in beverage and yoghurt. The purity of resistant dextrin should reach 82% in accordance with the national standards, but its application in clear drinks is restricted. In addition, the remaining glucose is also a major limiting factor for the food of the diabetic population.This paper mainly studied the preparation of resistant dextrin with high purity,analyzedits characteristics,and then applied it in Rice Wine and Wine, which was expected to provide the foundation for its popularization and application.Firstly,the corn starch was acidhydrolyzed and enzymolyzed by amylase and glucoamylase to get enzymatic hydrolysate(glucose content was 456.28g/L).The yeast fermentation on enzymatic hydrolysate was studied to further purification, it was found that Guoguang high active dry yeast has good capability of glucose utilization through screening yeast species. Fermentation for 24 h, the glucose content was reduced to 50.77g/L, then another low sugar yeast was used to second fermentation, the glucose content was only decreased to 39.18g/L, while the removal effect of residual glucose was better by 78% alcohol precipitation method. The purification effect of solvent precipitation method was studied, it was revealed that the precipitation effect of alcohol was better than that of acetone. The enzymatic hydrolysate should be concentrated before purification(control proportion of about 1.16g/m L), then precipitated with 95% ethanol of 4 times volume ratio, and washed with 78% ethanol for 6 times, and the production of resistant dextrinwith the purity of95.30%was obtained and the yield was 40.32%.Secondly,the conventional ingrediants,molecular weight distribution and thermal properties was studied,the results showed the high thermal stability and the heavy molecular weight was 8607 Da,the structure of corn starch was not exist. Infrared spectroscopyshowed it was polysaccharide. The surface tension of pure water,rice wine and red winecould be decreased by adding the resistant dextrin and the rheological property keep constant. Compared with the other soluble dietary fiber products–polydextrose, the resistant dextrin showed no significant difference both in decreasing the surface tension and keeping the rheological property(p<0.05). And the result of sensory evaluation showed that the organoleptic quality of new rice wine and red wine by adding 5%(w/v)resistant dextrin wereimproved by fuzzy comprehensive evaluation method. There was significant negative correlation between viscosity and surface tension in rice wine and red wine.The surface tension was not decreased significantly when the resistant dextrin was added to white wine. By compared the contents of polyphenol compound in rice wine, red wine and white wine, it was revealed that the level of polyphenol compounds in white wine was very low. Designing the experiment of resistant dextrin combined with polyphenol compounds, then compared the antioxidant capacity of resistant dextrin before and after combined with polyphenol compounds. It was confirmed that the polyphenol compounds was indeed bound to resistant dextrin to formed resistant dextrin-polyphenol compounds mixture; further, the mixture was added to rice wine and red wine, the viscosity and surface tension did not changemarkedly(p<0.05).It was explained that the mixture was no longer improving the quality of wine. Therefore, it can be guessed that resistant dextrin may be combined with polyphenol compounds to decrease the surface tension and increase the viscosity.These results not only apply a new technology for production of high purity resistant dextrin, but also give some idea for its application.