Ivo M Rodrigues1,2, M Graça Vs Carvalho2, Jorge Ms Rocha2. 1. CERNAS, College of Agriculture, Polytechnic Institute of Coimbra, Bencanta, 3045-601 Coimbra, Portugal. 2. CIEPQPF, Department of Chemical Engineering, Faculty of Sciences and Technology, University of Coimbra, 3030-790 Coimbra, Portugal.
Abstract
BACKGROUND: Rapeseed meal is a good source of high-quality vegetal protein but contains antinutritional compounds that limit its use for human and animal feed. The aim of this study was to develop a methodology to enhance alkaline protein extraction of rapeseed meal and to produce protein-rich products with low levels of phytic acid. Different phytase dosages and operating conditions were used for rapeseed meal pretreatment followed by alkaline extraction at different temperatures, time, pH and solid/liquid ratios (S/L). RESULTS: The highest protein extraction yield attained was 72.1%, for 2 h at 55 °C, with a phytase dosage of 0.8 U g-1 when the alkaline extraction was performed at 75 °C, pH 12.5 and 60 min for an S/L ratio of 10 g 100 mL-1 water. The extraction yields were higher than those previously obtained without enzymatic pretreatment. CONCLUSION: Phytase pretreatment enhanced alkaline extraction yield of proteins from rapeseed meal. This procedure allowed also the production of rapeseed protein concentrates with very low levels of phytic acid, ∼1 g kg-1 , improving their nutritional properties and commercial value. Moreover, after the pretreatment, the amount of phytic acid in the remaining rapeseed meal decreases about 25%.
BACKGROUND: Rapeseed meal is a good source of high-quality vegetal protein but contains antinutritional compounds that limit its use for human and animal feed. The aim of this study was to develop a methodology to enhance alkaline protein extraction of rapeseed meal and to produce protein-rich products with low levels of phytic acid. Different phytase dosages and operating conditions were used for rapeseed meal pretreatment followed by alkaline extraction at different temperatures, time, pH and solid/liquid ratios (S/L). RESULTS: The highest protein extraction yield attained was 72.1%, for 2 h at 55 °C, with a phytase dosage of 0.8 U g-1 when the alkaline extraction was performed at 75 °C, pH 12.5 and 60 min for an S/L ratio of 10 g 100 mL-1 water. The extraction yields were higher than those previously obtained without enzymatic pretreatment. CONCLUSION: Phytase pretreatment enhanced alkaline extraction yield of proteins from rapeseed meal. This procedure allowed also the production of rapeseed protein concentrates with very low levels of phytic acid, ∼1 g kg-1 , improving their nutritional properties and commercial value. Moreover, after the pretreatment, the amount of phytic acid in the remaining rapeseed meal decreases about 25%.