Protein classification of beach pea (Lathyrus maritimus L.)

Protein fractionation of whole seed, cotyledons and hulls of beach pea (Lathyrus maritimus L.) was carried out. Surface topography of pea protein isolates and protein fractions, as well as their polyacrylamide gel electrophoresis (PAGE), was studied. The nitrogen solubility of beach pea seed meal was minimum at pH 4.5. Globulin was the major protein fraction present and its content in whole seeds (57%), cotyledons (62%) and hulls (24%) of beach pea was lower than those of other common pea cultivars; the same was true for its albumin content. However, glutelin content in beach pea seed and its parts (cotyledons and hulls) was higher than those of other pea cultivars. The albumin fraction contained the highest amount of total sulphur-containing amino acids followed by glutelin, globulin and prolamine. The amount of sulphur-containing amino acids in beach pea protein fractions was higher than in other peas. Predicted biological value of albumin and glutelin fractions of beach pea was also higher than green pea and grass pea. Beach pea seed protein fractions showed different UV spectra from other pea cultivars. Protein isolate and protein fractions of beach pea seeds showed similar topographical characteristics to those of other peas. Major polypeptide bands in the range of 35–47 kDa in the protein isolate, as well as protein fractions for beach pea, were detected by PAGE.