Optimal Enzymatic Hydrolysis of Sweet Lupine Protein towards Food Ingredients

Abstract

Although its high protein content, bioactive compounds, and dietary fibers have many health benefits, lupine (Lupinus sp.) was undervalued as a resourceful plant. In the last years, however, the number of studies on the use of lupine as a potential food ingredient has increased. In this study, obtaining a sweet lupine protein concentrate (SLPC) hydrolysate with a high degree of hydrolysis (DH) and a simultaneous low intensity of bitterness was pursued. The experimental design was carried out, according to Taguchi methodology, using three experimental parameters: enzyme concentration (0.5–1.5%), temperature (50–60 °C), and time (1–4 h), with three levels each. The optimal conditions for the enzymatic hydrolysis process of SLPC with Alcalase 2.4 L were enzyme concentration 1.5%, temperature 50 °C, and time 4 h, for which the best DH, 41.96%, was achieved. The SLPC hydrolysate as a food ingredient was characterized in terms of DH, bitter taste intensity, amino acid profile, and techno-functional properties. The results showed an increase of water binding capacity to 1.45 g/g, emulsification activity of 50.91%, and 92% stability of the emulsion, while the evaluated intensity of bitterness was 4.6 on a 7- point scale. Based on its technological, functional, sensory, and chemical characteristics, this study recommends the use of SLPC hydrolysate as a food ingredient in various food matrices.