Degradation of polysaccharides from Lycium barbarum L. leaves improves bioaccessibility and gastrointestinal transport of endogenous minerals

Acidic heteropolysaccharide (LP) from Lycium barbarum L. leaves has compact globular structure which wrapped abundant endogenous minerals inside by ionic interactions with uronic acid. This study investigated the efficacy of chemical degradation of LP on the bioaccessibility and transport of endogenous minerals in simulated gastrointestinal fluids. Results showed that the degradation using vitamin C and hydrogen peroxide mildly decreased LP molecular weight from 162.0 kDa to 94.3 kDa, and the structure of degraded LP (LPD) was converted to loose coil. After the simulated intestinal digestion, the accessibility of Ca, Fe, Zn, and Mg in LPD increased by119%, 52%, 103% and 112.5% compared with the intact LP, respectively, and in particular, the uptake rate increased by 15.8%, 8.1%, 23.4% and 21.6% for Ca, Fe, Zn, and Mg, respectively. These results demonstrated that the chemical degradation is a helpful strategy to improve the uptake of endogenous minerals wrapped in polysaccharide. (C) 2019 Elsevier B.V. All rights reserved.