Effects of deacetylated konjac glucomannan on the quality characteristics, staling and digestion of Chinese steamed bread

Abstract

This study aimed to explore the effect of deacetylated konjac glucomannan (DKGM) on the quality characteristics, staling, and digestive properties of Chinese steamed bread (CSB). The findings revealed that the addition of DKGM led to a larger specific volume, a lighter and more yellowish crumb color, and a softer texture of the CSB. Notably, 0.6% DKGM with a deacetylation degree (DD) of 50.26% integrated with the gluten network resulted in a more stable gluten structure in the dough and a 5.74% increase in the CSB specific volume, reaching 3.13 mL/g. Moreover, higher deacetylation of KGM (DD = 66.61%) significantly delayed CSB aging, as evidenced by factors such as freezable water content, staling rate, and starch crystallinity. High deacetylation of KGM exhibited the optimum digestive resistance of CSB. 1% KGM with high DD (DD = 66.61%) led to a 10.21% decrease in the rapidly digested starch content and a 3.98% decrease in the starch hydrolysis rate compared with the KGM, which might be attributed to highly deacetylated KGM may form stronger hydrogen bonds with starch. This study offered insights into the application of DKGM in advancing the industrialization of CSB.