Isolation of Dictyophora indusiata polysaccharide and its effects on the multi-structure characteristics and in vitro digestion of extruded rice starch
Hai He, Yuting Hao, Chao Ai, Ke Wang, Wenzhen Liao, Jie Shen
Abstract
This paper described the structure changes that occur in rice starch when extruded with a polysaccharide from Dictyophora indusiata (PDI) at different concentrations (0%, 1%, 2%, and 3%, w/w), their interactions, and the in vitro digestion. The mannose, glucuronic acid, galacturonic acid, glucose, and galactose were found in PDI with the content of 30.20%, 1.66%, 0.62%, 62.50%, and 5.03%, respectively. Fourier transform infrared spectroscopy showed that PDI contains pyranose rings. PDI could cause the starch chains to rearrange to generate a more ordered aggregate structures (such as short-order structure, helix structure, or crystalline structure). After adding PDI, the consistency coefficient (K), viscosity, and storage/loss modulus (G’/G”) of the starch-PDI complex increased. Finally, PDI addition markedly inhibited the activity of the starch digesting enzyme, thereby increasing the slowly digested components/resistant components (SDC/RC), while reducing the rapidly digested components (RDC). Overall, this study demonstrated that the relationship between the digestibility and structure of rice starch-PDI complex and provided an insight for application of PDI in rice starch-based food products.