Characterization of Lentinus edodes β-glucan influencing the in vitro starch digestibility of wheat starch gel

- Lentinus edodes β-glucans can reduce the rate of starch digestion in vitro.
- The pasting temperature and enthalpy rose with increment of β-glucans.
- The strong interactions between Lentinus edodes β-glucans and wheat starch existed.
- Lentinus edodes β-glucans can increase the content of SDS and RDS and decrease pGI.

Lentinus edodes β-glucan (abbreviated LEBG) was prepared from fruiting bodies of Lentinus edodes. The average molecular weight (Mw) and polydispersity index (Mw/Mn) of LEBG were measured to be 1.868 × 106 g/mol and 1.007, respectively. In addition, the monosaccharide composition of LEBG was composed of arabinose, galactose, glucose, xylose, mannose with a molar ratio of 5:11:18:644:16. After adding LEBG, both G′ and G″ of starch gel increased. This is mainly because the connecting points between the molecular chains of LEBG and starch formed so that gel network structures were enhanced. The peak temperature in the heat flow diagram shifted to a higher temperature and the peak area of the endothermic enthalpy increased. Furthermore, LEBG can significantly inhibit starch hydrolysis. The predicted glycemic index (pGI) values were reduced when starch was replaced with LEBG at 20% (w/w). It might indicate that LEBG was suitable to develop low GI noodle or bread.