Preparation, physicochemical properties, and in vitro digestibility of cross-linked resistant starch from pea starch

Starch in its native form may not be able to provide functional properties. Therefore, it is usually modified to make it compatible for different applications. The main aim of this research was to study the effect of cross-linking on physicochemical properties of pea starch. Therefore, starch was first cross-linked using different levels of sodium trimetaphosphate and sodium tripolyphosphate (99:1, w/w) to prepare RS4. The solubility and swelling power of RS samples decreased significantly with the increase of RS content. Cross-linked RS showed C-type XRD pattern with an increased relative crystallinity. The viscosity of RS samples decreased dramatically, and viscosity of heavily cross-linked samples dropped to around zero. The gelatinization temperatures of cross-linked starch increased, whereas melting enthalpy slightly decreased. The FT-IR spectra of cross-linked starch showed that the ratio of 1047 and 1022/cm was greater, indicating that the amount of ordered starch to amorphous starch in cross-linked starch was greater.