Effects of Lycium barbarum Polysaccharide on Pasting, Rheology, and In Vitro Digestibility of Starch

Lycium barbarum polysaccharide (LBP) is widely used in functional foods, but it is rarely used in starchy foods. This study aims to evaluate the effects of LBP on the pasting, rheological, textural properties, and digestibility of different types of starch (wheat starch (WS), sweet potato starch (SPS), and pea starch (PS)). Results show that LBP increases the pasting characteristics of PS but shows decreasing and no influence on these characteristics in WS and SPS, respectively. The apparent viscosity of SPS paste decreases with the increase in the LBP content. LBP reduces the hardness, adhesion, and chewiness of PS gels, as also evidenced by the alterations in the microstructure. The results of FT-IR and X-ray diffraction indicate that LBP promotes the formation of ordered structures within retrograded starch. LBP increases the slowly digested starch and resistant starch content, implying that LBP decreases the digestibility of starches. The changes in the physicochemical properties of starches depend on the interactions between starch and LBP.