Hydrolysis and Ultrafiltration Treatment to Improve the Nutritive Value of Rapeseed Proteins

In order to improve their nutritive value, rapeseed proteins were hydrolyzed with pepsin (60 min) and trypsin (120 min). The hydrolysate was centrifuged at 10,000 × g for 10 mln and the soluble fraction was ultrafiltered with a Romicon cartridge having a molecular weight cut‐off of 10,000 daltons. Nutritional experiments with rats demonstrated that the net protein ratios obtained with rapeseed hydrolysate and ultrafdtrate (4.68 and 4.55 respectively) were higher (P < 0.05) than that of casein (4.40). The protein digestibility of the ultrafiltrate (90.3) was not different from that of casein (91.1) but higher than that of raw rapeseed flour (81.9). These hydrolysis and ultrafiltration treatments improved the nutritive value of rapeseed proteins by permitting the isolation of by‐products of a molecular weight lower than 5000 daltons.