Genes affecting starch biosynthesis exert pleiotropic effects on the protein content and composition of pea seeds

We have used a series of near-isogenic mutant pea lines defective in starch biosynthesis to identify genes that exert pleiotropic effects on the prote in content and composition of the pea seed. The total protein contents of t he flours obtained from the dry seed of these lines, determined using a new method based on amino acid analysis and validated by near-infrared reflect ance spectroscopy, ranged fi om 19 to 28% of dry matter. Modifications in t he legumin (11S)/vicilin (7S) ratios were confirmed by analytical ultracent rifugation and accompanied by compensatory increases in the albumin (2S-4S) content, Improving the albumin fraction of plant protein can be used to im prove its nutritional value. There is additional variability in the solubil ity profiles for the protein in these lines. This variability has implicati ons for the functional properties, processing behaviour, potential industri al applications, digestibility and nutritional value of the different pea m eal and the protein ti actions derived therefrom. Digestibility of the prot ein in meal and in air-classified and extruded products from selected lines will be compared in nutritional evaluation trials with poultry to assess t he suitability of these products for incorporation into animal diets. (C) 2 001 Society of Chemical Industry.