Rheological properties of a neutral polysaccharide extracted from maca (Lepidium meyenii Walp.) roots with prebiotic and anti-inflammatory activities.

The rheological, prebiotic, and anti-inflammatory properties of neutral polysaccharide extracted from maca roots (MP) were investigated. MP was composed of arabinose, galactose, rhamnose, and glucose. In steady shear rheological properties, an increasing concentration of MP solution exhibited higher apparent viscosity (η_a,100) and consistency index (K) under acidic condition (pH 4). In dynamic rheological properties, the dynamic moduli (G' and G″) in the frequency sweep test from the MP solution were increased with increasing concentration and decreasing pH. The changes in dynamic moduli of the MP solution with various concentrations and pH values were stable during 1 h storage at 4 °C due to the enhancement of hydrogen bonding. According to the results of the temperature sweep test, an increasing concentration of MP solution increased dynamic moduli under acidic conditions. The prebiotic properties of MP induced a higher growth of Bifidobacterium longum ATCC15707 and Lactobacillus rhamnosus ATCC 7469 than inulin and increased acetic acid, propionic acid, and butyric acid more than inulin in vitro. Furthermore, MP inhibited lipopolysaccharide-induced NO production in RAW 264.7 cells, which indicated that an increasing concentration of MP enhanced anti-inflammatory activities. Therefore, MP is a potential functional material for the food and pharmaceutical industries.