Effects of food polysaccharides and seaweed calcium on the physicochemical properties of prickly pear extract fermented by Lactobacillus rhamnosus LS.

摘要

Effects of polysaccharides (0.2% carrageenan, glucomannan, xanthan gum or gellan), seaweed Ca or seaweed calcium carbonate, alginic acid, pectins and dextran on the physicochemical properties of prickly pear extract fermented by Lactobacillus rhamnosus at 30degC for 2 days were determined. Viable cell counts, flow behaviour, titratable acidity and colour of fermented prickly pear extract were subsequently determined after 4 wk of cold storage. Xanthan gum and glucomannan increased the apparent viscosity and acids production, and viable cell count and red colour were maintained throughout cold storage. However, fermenting prickly pear extract with gellan gum resulted in a decrease in the relative absorbance, indicating lower colour stability. Adding carrageenan or alginic acid to prickly pear extract reduced the production of acid and lowered the viable cell count. Adding seaweed Ca (0.1%) had positive effects on colour stability and helped maintain a viable cell count of 4.1 x 109 cfu/ml. It is concluded that xanthan gum can be used as a thickener and stabilizer for retaining the viable cell count and red colour of fermented prickly pear extract beverage during cold storage.