Protein isolates from two Mediterranean legumes: Lathyrus clymenum and Lathyrus annuus. Chemical composition, functional properties and protein characterisation

Abstract

Protein isolates were analysed from two Mediterranean legumes, Lathyrus clymenum and L. annuus. Protein isolates were prepared by alkaline extraction, including sodium sulphite and acid precipitation of Lathyrus proteins at their isoelectric point (pH 4.5). The percentage of proteins recovered from L. annuus and L. clymenum flours during the preparation of the protein isolates was around 60%. Chemical composition, nutritional parameters, main functional properties and protein composition of Lathyrus protein isolates were studied. L. annuus and L. clymenum protein isolates contained 81.07% and 82.4% of proteins, respectively, and they have a balanced content of essential amino acids, except for sulphur amino acids, with respect to the FAO pattern. The in vitro protein digestibility increased in the protein isolates to 93% and 95% in L. annuus and L. clymenum, respectively. Functional properties were similar to those observed in other legumes protein isolates. These results confirm the interest of local crops as sources of high value protein products obtained after convenient protein extraction procedures and the removal of antinutritional components. These high added value protein isolates are of interest for the food industry and for the revalorisation of L. annuus and L. clymenum favouring the bioconservation of Lathyrus.