Regulation of the Gel Properties of Konjac Glucomannan and Deacetylated Konjac Glucomannan on Various Starches and the Processing Performance of Vermicelli

Several faults have been observed during the preparation of starch-based foods, including low gel strength, thermal instability, and a high glycemic index. Supplement of exogenous polysaccharides is effective to overcome the defects in starch processing. In this study, the effects of konjac glucomannan (KGM) and deacetylated konjac glucomannan (DKGM) on the gelatinization and pasting properties of 10 kinds of natural starches were compared. The processing stability, texture characteristics, and antidigestion performance of Solanum starch-DKGM composite vermicelli were focused. Results showed that the supplement of DKGM led to more significant improvement in the viscoelastic properties compared to KGM in the most starch. Conversely, KGM had a greater contribution to the viscosity during the starch gelatinization process. Thus, DKGM significantly enhanced the water retention and freeze-thaw stability of starch gels. Additionally, DKGM significantly decreased the cooking loss and enhanced the antideformation ability of vermicelli. Antidigestive performance was also found in Solanum starch-DKGM composite vermicelli, with the reduction of 7.88% RDS and 7.15% SDS and the increase of 15.03% RS in 2% DKGM treatment. We hope this work could provide theoretical support for the starch-based gel foods development.