Effects of non-starch polysaccharides on physicochemical properties and in vitro starch digestibility of rice starches

The effects of non-starch polysaccharides (NSPs) on physicochemical properties and starch digestibility of waxy and non-waxy rice starches (WS and NWS) were investigated. The NSPs studied included guar gum (GG), xanthan gum (XG), carboxymethyl cellulose (CMC), tapioca fibre (Tap) and tamarind seed fibre (Tam). They were added to WS and NWS at the levels of 5, 10 and 15 g/100 g dry sample. The mixtures were examined for their in vitro starch digestibility, thermal properties by a DSC and textural properties by a texture analyser. Generally, it was found that all NSPs at the concentrations used in this study had little or no effect on starch digestibility. Glycaemic response parameters slightly decreased in the samples with added NSPs. No obvious effects on thermal properties were obtained. However, the NSPs affected the texture of rice starch gels as evidenced by changes in hardness and adhesiveness values. The textural changes were dependent on the type and concentration of the NSPs.