In vitro digestion and structural properties of rice starch modified by high methoxyl pectin and dynamic high-pressure microfluidization

Abstract

The rheological, structural properties and in vitro digestibility of starch with high methoxyl pectin (HMP) and further modified by dynamic high-pressure microfluidization (DHPM) were investigated. The viscosity and elasticity increased on addition of HMP and were more pronouncedly affected by 10% HMP. However, after DHPM treatment, the viscosity and elasticity decreased with increasing DHPM pressure. After 100 MPa DHPM treatment, the ordered and crystalline structures were further increased compared with starch-HMP mixtures. A compact and dense surface of starch paste was formed under 100 MPa DHPM and 10% HMP treatment, thus significantly slowing down the digestibility. In contrast, the crystalline and semicrystalline structure of starch were disrupted by intense shear force under 200 MPa DHPM. This study provides theoretical information regarding starch-HMP interaction and improves their functional and physicochemical properties through a promising strategy for better applications in food formulation.

Keywords: Crystalline structure; Lamellar structure; Pectin; Rheological properties; Short range ordered structure; Starch.