Production, purification and analysis of the isomalto-oligosaccharides from Chinese chestnut (Castanea mollissima Blume) and the prebiotics effects of them on proliferation of Lactobacillus

The synthesis and stimulating effects of isomalto-oligosaccharides from Chinese chestnut starch (CN-IMOs) on Lactobacillus proliferation were investigated in this paper. The synthesis process of CN-IMOs mainly consisted of liquefaction, saccharification and transglycosylation in sequence. The optimal liquefaction time with heat-stable a-amylase and CaCl2 was 120 min, and the dextrose equivalent value of the liquefied slurry was 13.8. Saccharification was performed at 60 degrees C for 2 h by using a complex enzyme system comprising fungal alpha-amylase, beta-amylase and pullulanase. The hydrolysate was then subjected to transglycosylation with alpha-transglucosidase for 20 h. The syrup contained 30.53% total CN-IMOs, and then was purified by 732 cation exchange resins (Nat). The recovery rate and total content of it was 91.6% and 61.5%, respectively. Moreover, the proliferative effects of CN-IMOs, purified CN-IMOs (CN-IMOs-P), and commercial isomalto-oligosaccharides (IMOs-50) on Lactobacillus were observed in vitro. CN-IMOs-P was the best effective carbon source for Lactobacillus growth at an optimal dosage of 2.0% in the medium. All the results showed that Chinese chestnut could be a potential raw material for IMOs production, which was a new further processing area of chestnut utilization, and CN-IMOs-P can be explored as a novel prebiotic healthcare product for human gastrointestinal health. (C) 2017 Published by Elsevier B.V. on behalf of Institution of Chemical Engineers.