A starch‑sodium alginate interpenetrating network enhances the structure, texture, and starch digestibility of extruded buckwheat noodles: Regulatory effects of mannuronate/guluronate ratios and calcium ion concentrations

The regulatory effects of different mannuronate/guluronate ratios in sodium alginate (SA) and calcium ion (Ca 2+ ) concentrations on the structure and properties of starch-SA interpenetrating polymer network (IPN)-enhanced extruded buckwheat noodles were investigated. The thermal stability of buckwheat noodles was improved by increasing the G block proportion, and 1% Ca 2+ concentration led to the highest thermal stability. With increasing G proportion and Ca 2+ concentration, cooking loss and elongation at break of extruded noodles gradually decreased. The cooking time initially decreased and then increased. Noodle hardness, chewiness, and breaking strength significantly increased. In vitro starch digestion showed that when the SA M/G ratio was 1:2 and the Ca 2+ concentration was 1%, the predicted glycemic index of noodles was the lowest and the resistant starch content was the highest. According to curve fitting based on the sensory evaluation results, the overall noodle acceptability was higher when hardness was between 3800 and 5200 g.