Functional properties of protein isolates from beach pea (Lathyrus maritimus L.)

Protein isolates of beach pea were prepared using sodium hydroxide (NaOH) and sodium hexametaphosphate (SHMP). Functional properties of the isolates so prepared were investigated and compared with those of other pea samples. Protein isolate of beach pea, prepared via NaOH extraction, had a protein content of 86.6%, while SHMP-extracted isolates contained 85.1% protein. Corresponding values for NaOH- and SHMP-extracted green pea and grass pea were 90.6, 89.9, 90.6 and 88.3%, respectively. Sulphur-containing amino acids were more prevalent in SHMP-extracted beach pea and green pea, while they were higher in NaOH-extracted grass pea. Tryptophan content was higher in NaOH-extracted than SHMP-extracted isolates. The predicted biological value and protein efficiency ratio of beach pea protein isolates indicated the high quality of products so prepared. Beach pea protein isolates exhibited a minimum solubility at pH 4.5. The pH and NaCl concentration effectively changed the functional properties of protein isolates. Beach pea protein isolates (NaOH- and SHMP-extracted) had in-vitro digestibility of 80.6 to 82.6% for pepsin-trypsin and 78.6 to 79.2% for pepsin-pancreatin.