PROTEIN ISOLATE OF RICE FLOUR: CHARACTERIZATION E FUNCTIONAL PROPERTIES

Abstract

The aim of this study was to isolate proteins from rice flour using an enzymatic method with the enzyme Termamyl®. The functional properties of solubility, water and oil holding capacity, emulsifying capacity, foam property and "in vitro" digestibility in flour and isolate were determined. The protein isolate was obtained after the reaction with the enzyme Termamyl® during 90 minutes at 90 ºC. The slurry was then filtered and dried at 35 ºC during 24 hours, obtaining 91.2 % of protein (dry basis) in the isolate. The values of the functional properties presented by the rice flour were: 17.8 % solubility at pH 10 and 6.2 % at pH 5; 1.13 mL oil/g of protein of emulsifying capacity; 2.46 g/g of sample of water holding capacity; oil holding capacity of 1.61 g/g of sample, and "in vitro" digestibility of 57.6 %. The protein isolate presented the following values: solubility of 7.4 % at pH 11 and 1.1 % at pH of 4.5; emulsifying capacity of 3 mL oil/g of protein, water holding capacity of 5.4 g/g of sample and oil holding capacity of 6.3 g/g of sample and "in vitro" digestibility of 83.6 %. All the isolate functional properties values, except the solubility, were better than the raw material values.