Improvement of Functional Properties of Rapeseed Protein Concentrates Produced via Alcoholic Processes by Thermal and Mechanical Treatments

Plant protein products produced via alcoholic extraction procedures often show a deterioration of their functional characteristics. The aim of this study was to modify rapeseed protein concentrates (RPCs) obtained by alcoholic extraction using different treatments in order to reconstitute their functional properties and to evaluate the influences of different modification procedures. It could be shown that a heat treatment at alkaline pH resulted in significant lower emulsification capacity (232 mL/g) but led to amelioration of water binding capacity (4.9 mL/g) and emulsion stability (95%). Heat treatment was also connected with loss in protein solubility whereas homogenization at high pressure revealed maintenance of protein solubility of the RPC concurrent with a significant higher emulsion capacity (357 mL/g) and emulsion stability (83%) in comparison with the untreated RPC (335 mL/g and 56%, respectively). Homogenization technique for RPC seems to be a promising tool for the development of applications in bakery or meat products. PRACTICAL APPLICATIONS The German Federal Ministry of Education and Research project Napus 2000 investigated how the use of rapeseed could be improved. The key objectives of this project were to utilize all the rapeseed and to use modern methods of genetic engineering in combination with classical plant cultivation to improve the rape products and so make a contribution to more healthy nutrition. More than 15 famous industrial partners and scientific institutions participated in this project. The key work fields in Napus 2000 were neutral lipids, proteins, antioxidants and polar lipids. The main work area of the Fraunhofer IVV was on proteins and this work covered the development of methods to recover proteins and potential applications of the rape protein products in foods.