Nutritional quality of blended foods of rice, soy and lupins, processed by extrusion

Production of Antioxidant Hydrolyzates from a Lupinus mutabilis (Tarwi) Protein Concentrate with Alcalase: Optimization by Response Surface Methodology

Lupinus mutabilis (tarwi) is a cultivated legume used principally as a protein source in human and animal nutrition. In this study, protein concentrate was obtained from debittered and defatted tarwi seed flour. SDS-PAGE analysis revealed the presence of highly intense bands ranged between 35 and 60 kDa. Tarwi protein concentrate was subjected to the action of alcalase to produce hydrolyzates with antioxidant activity. A central composite design was employed to study the effect of the experimental variables, enzyme/substrate ratio and incubation time, on the degree of hydrolysis and the radical scavenging capacity. The influence of both variables on the variable responses was demonstrated. The optimal conditions to obtain the highest degree of hydrolysis were enzyme/substrate ratio of 1.72% and 133 min of incubation. The highest radical scavenging activity (TEAC value of 2.7 ± 0.1 μmol Trolox equivalents/mg protein and ORAC value of 3.8 ± 0.1 μmol Trolox equivalents/mg protein) was found in hydrolyzates with alcalase after 138 min and an enzyme/substrate ratio of 1.87%. Peptides released by the action of alcalase and containing hydrophobic and aromatic amino acids could contribute to the antioxidant effects observed. Tarwi proteins could be a new alternative as a food additive with antioxidant properties or as an ingredient of functional foods for health promotion and prevention of free radical-induced chronic diseases.

Lupinus mutabilis: Composition, Uses, Toxicology, and Debittering

Lupinus mutabilis has protein (32.0-52.6 g/100 g dry weight) and lipid (13.0-24.6 g/100 g dry weight) contents similar to soya bean (Glycine max). The Ω3, Ω6, and Ω9 contents are 1.9-3.0, 26.5-39.6, and 41.2-56.2 g/100 g lipid, respectively. Lupins can be used to fortify the protein content of pasta, bread, biscuits, salads, hamburgers, sausages, and can substitute milk and soya bean. Specific lupin protein concentrates or isolates display protein solubility (>90%), water-absorption capacity (4.5 g/g dry weight), oil-absorption capacity (3.98 g/g), emulsifying capacity (2000 mL of oil/g), emulsifying stability (100%, 60 hours), foaming capacity (2083%), foaming stability (78.8%, 36 hours), and least gelation concentration (6%), which are of industrial interest. Lupins contain bitter alkaloids. Preliminary studies on their toxicity suggest as lethal acute dose for infants and children 10 mg/kg bw and for adults 25 mg/kg bw. However, alkaloids can also have medical use for their hypocholesterolemic, antiarrhythmic, and immunosuppressive activity. Bitter lupins can be detoxified by biological, chemical, or aqueous processes. The shortest debittering process requires one hour. This review presents the nutritional composition of lupins, their uses (as food, medicine, and functional protein isolates), toxicology, and debittering process scenarios. It critically evaluates the data, infers conclusions, and makes suggestions for future research.