Processes for producing lupin protein isolates
The HEALTHY-PROFOOD project aimed to obtain food ingredients from lupin seeds. Two different processes have been developed for the production of lupin protein isolates (LPIs). This included an innovative procedure from Fraunhofer IVV, for separating native protein products from sweet white lupin seeds. The process involved the cleaning, de-hulling and flaking of the seeds, followed by de-oiling with hexane. The resulting white flakes are input material for protein extraction, which was carried out in a new pilot facility. A second partner, Bioraf, developed a process based on the use of enzymes and the subsequent ultrafiltration of the protein extract. The result was a native protein concentrate, Protein VI, with a fat content around 7.8% and a protein concentration of 80-90%. The remaining material contained lipids, lipid soluble compounds and ash. Lipid soluble compounds such as fat soluble vitamins and phenolics contribute as antioxidants and are partly retained in the protein product VI. Evaluation of Protein VI showed that the emulsifying properties were competitive in different applications compared to solvent defatted protein isolates. However, Protein VI did not show foaming properties. Both processes were studied using cost models, which showed that the processing of white and yellow lupins into LPIs would be economically viable. Terrena, a third partner, was responsible for selecting and supplying lupin seeds. Three varieties gave good results, Aster, a winter variety and Energy and Ares, which are springtime varieties. Selection criteria involved stability of the protein, fat and fibre content, and low levels of antinutritional compounds (particularly alkaloids). Terrena produced an improved flour so it could be used as a raw material in concentrate and isolates production.
