OptiRaps

To date, four different rapeseed protein isolates (RPI) have been examined with regard to their composition, physicochemical characteristics, and techno-functional properties. It was shown that three of the samples had protein contents > 80%. Only the protein content of the napin-rich rapeseed protein was significantly lower (< 50%). The residual fat content of this sample was relatively high at 31.8%, which caused problems for the planned hydrolysis experiments. The hydrolysis of the napin-rich rapeseed protein was made possible by removing the fat via supercritical CO₂ extraction. In studies conducted by the project partner, the Technical University of Munich, RPI 1 (CanolaPro) was characterized as the least bitter and RPI 5 (Puratein C) as the most bitter RPI. Accordingly, these two samples were selected for the studies on the production of RPPH. In initial exploratory hydrolysis experiments, RPI 1 was hydrolyzed under comparable process conditions (temperature, pH) using six different enzymes, while varying the hydrolysis duration (t = 60 min / 240 min). The degree of hydrolysis of the RPPH was determined using GPC. It was found that the hydrolysis of napin and cruziferin proceeded at different rates: Only one enzyme (FP 343) hydrolyzed both storage proteins to a large extent, whereas the other enzymes caused the hydrolysis of only one of the two proteins. Further work includes the individual optimization of hydrolysis (varying temperature and pH) for each enzyme, as well as scaling up the hydrolysis to a pilot plant scale.