Chemical and Nutritional Evaluation of Protein-Rich Ingredients Obtained Through a Technological Process from Yellow Lupin Seeds (Lupinus Luteus)

In recent years, interest in plant-based proteins has been rising due to ethical and sustainability issues. In this context, the production of protein concentrates and isolates from new plant sources have increased enormously because of their nutritional and techno-functional properties. Therefore, this work describes a pilot process for obtaining protein-rich ingredients from a yellow lupin variety (Lupinus luteus) developed by the Agriaquaculture Nutritional Genomic Center (CGNA). A protein alkaline solubilisation followed by isoelectric precipitation was used as a method for obtaining a protein concentrate (LPC) and isolate (LPI) with 75 and 95% protein, respectively. The changes in the protein quality and chemical composition during the protein concentration process from lupin flour were evaluated. Thus, nutritional parameters such as the amino acids (AAs) profile, essential amino acid index (EAAI), chemical score (CS), the protein efficiency ratio (PER), and digestible indispensable amino acid score (DIAAS) were determined to evaluate the nutritional quality of LPC and LPI. The facile and scalable protein isolation method without a defatting process proposed in this study showed a great protein separation efficiency (PSE), while the amino acids profile was not affected during both the concentration as well as the isolation of proteins. In addition, SDS-PAGE showed that both LPC and LPI mainly contained the high-molecular-weight proteins α and β-conglutins. Both LPC and LPI had a balanced amino acids profile, and arginine was the most predominant amino acid. These results are useful for increasing the use of lupin based-protein ingredients as a potential functional ingredient in the food industry.