Protein Extraction from Heat‐stabilized Defatted Rice Bran: II. The Role of Amylase, Celluclast, and Viscozyme

Abstract

The effectiveness of 3 carbohydrases for protein extraction from heat-stabilized defatted rice bran (HDRB) was evaluated. Amylase, viscozyme and celluclast extracted a maximum of 45.4, 12.1, and 28.5% protein, respectively. Further study showed that extracted protein ranged from 9.5 to 58.4% under conditions of water to bran ratio (5:1 to 20:1), a-amylase (0 to 110000 units/10 g rice bran), temperature (35 to 55 °C), and time (1 to 8 h). The maximum protein extracted was 58.4% with a water to bran ratio of 17:1, 87637 units amylase, and 50.9 °C. These results suggest that impure food-grade amylase containing protease is more effective than celluclast and viscozyme in protein extraction from HDRB.

Ohmic heating as a pre-treatment in solvent extraction of rice bran

“…These constitute nearly 20-24 %, 5-10 %, 1-2 % and 2-3 % of the total milled rice respectively. Rice bran contains high quality proteins and edible oil apart from fibre, ash and NFE (nitrogen free extract) and it is highly nutritious containing less cholesterol (Tang et al 2003;Mahanta, and Bhattacharya 2010). The presence of enzyme lipase is detected in rice bran which becomes active after milling.…”

Effects of Rice Bran Protein Hydrolysates on the Physicochemical Stability of Oil-in-Water Emulsions

“…By using a-amylase, protein extraction could be promoted by hydrolyzing a-1,4-glycosidic linkage to release starch bound proteins 7 . Tang et al 18 , also reported a potent ability of a-amylase to recover proteins from plant cellular matrix 13 . Considering Viscozyme-L, it is a cocktail enzyme consisting of arabinase, cellulase, β-glucosidase, hemicellulase, and xylanase, so it might effectively enhance protein liberation from the matrix 7,18 .…”

“…Generally, EAI tended to increase with increasing DH suggesting improved emulsion formability of the more hydrolyzed peptides. This behavior could relate to developed S 0 and solubility at higher DH levels 5,18 . Increased S 0 enhanced protein adsorption on oil drop surfaces, resulting in improved EAI 5 .…”

“…For the defatted rice bran used in the present work, it was treated by heating to inactivate lipoxygenase during oil extraction process. This affected to stiff protein extractability since heating affected to enhance denaturation and interaction of protein with other components 18 . In plant cells, proteins were always bound with starch granules 7 and other polysaccharide residues which were mainly cellulose, hemicelluloses, and xylose for rice bran 12 .…”

“…A small aliquot of NaOH or HCl 0.1N was used to re-adjust pH of the mixture to 11, before heating at 45 1 for 0-3 h with sonicator: 40 Hz, Transsonic 460/H; Elma, Singen, Germany or without sonication at 40 Hz water bath: Memmert, Schwabach, Germany . Enzyme-assisted extraction: For enzyme-assisted extraction, rice bran and DI water were mixed at the abovementioned ratio, and the pH of the mixture was adjusted to optimum conditions pH 4.1 and 6.25 for Viscozyme L and a-amylase, respectively 18 . Enzymes were then introduced at a concentration of 0.5 by weight of the bran, followed by heating at 45 1 for 0-3 h with or without sonication.…”