Protein isolates were prepared from full-fat flakes of Lupinus angustifolius L. (cv Vitabor) by salt-induced extraction followed by precipitation with cold demineralized water. Different process parameters were screened to evaluate their significant influences on the extracted or overall protein yields in lab scale. During the extraction, the factors NaCl concentration, pH value and the ratio of flakes to solvent significantly influenced the protein yields, whereas the extraction time can be neglected in a specific range. During precipitation, the salt concentration, the initial protein concentration, the ratio between extract and water, and finally the sedimentation time had significant effect on the overall protein yield. However, the temperature difference between extract and water as well as the order and speed of addition had no considerable impact on the final protein yield. This study gathered important processing parameters for an efficient protein isolation and their suitable ranges for a subsequent optimization.
PRACTICAL APPLICATIONSIn search of viable ways to create more sustainable diets, the application of dietary proteins from plant-based sources would be an appropriate possibility. Plant proteins, in particular protein isolates, will find an introduction into the world's food system as extenders, supplements and replacements of animal proteins. Currently, the major drawback of protein isolate production is its insufficient economical efficiency including cost-efficient processing and low recovery yields. Although some important parameters on protein isolation are well established, systematic studies on overall yield including all relevant processing parameters are still scarce. This study identified significant process parameters on the overall protein yield using lupin seed as an example. These findings are a prerequisite for further optimization to obtain plant protein isolates in an efficient and systematic way. This knowledge will facilitate the implementation of plant protein processing on industrial scale and will ensure appropriate amounts of protein isolates with superior quality. bs_bs_banner
Journal of Food Process Engineering