Precipitation of rice bran protein using carrageenan and alginate

Precipitation of rice bran protein, a high-quality nutritional protein, using polysaccharides (alginate and carrageenan) was investigated at various pH, temperature and amount of polysaccharide with the objective of obtaining higher protein recovery and possible wider industrial application. Both alginate and carrageenan were found to be effective in precipitating rice bran protein. At pH 3.5, the maximum amount of protein precipitated were 95% for a carrageenan-to-protein ratio of 2:1, and 93% for an alginate-to-protein ratio of 1:1. However, change of temperature (20–55 °C) did not have a significant effect (p > 0.05) on the amount of protein precipitated. The precipitate formed using alginate and carrageenan had protein content of 42.15 and 26.48 g/100 g of precipitate, respectively. The freeze dried product obtained from the rice bran extract precipitated with polysaccharides was capable of forming foam and emulsion, indicating its possible utilization as a food ingredient.