Protein fractions of lupin seed meal: Quantitative importance and amino acid composition

Abstract

Protein contained in the seed of Lupinus angustifolius L., L. albus L., L. luteus L., L. pilosus L. and L. cosentinii Guss has been fractionated by a modification of the classical Osborne method. Protein was isolated from the extraction fractions by precipitation with trichloroacetic acid (TCA). In all instances the albumin and glutelin extracts constituted a significant proportion of the total nitrogen extract, and the precipitable albumin proteins were present in quantities comparable to the globulin proteins. The amino acid analyses and essential amino acid indices (EAA index) of the protein fractions indicate that the albumin and glutelin fractions are valuable contributors to the nutritional value of the lupin seed.

Keywords:

• lupins
• proteins
• albumins
• globulins
• glutelins
• essential amino acids