Comprehensive Examination of Protein Distribution Profile in Macadamia Nut (Macadamia ternifolia)

Abstract

The protein profile of defatted macadamia nut was examined comparatively after sequential extraction with water,1M NaCl,60% ethanol and 0.05 M NaOH solutions. Recovery of protein in the extract was 97%. Water soluble fraction (albumin fraction) was about 70% of the total protein, but NaCl and ethanol soluble fractions (globulin and prolamin fractions) were small. These four soluble fractions exhibited distinct individualities upon examination by 8M urea polyacrylamide gel electrophoresis. Amino acid analysis indicated that these four fractions had a similar amino acid composition characterized by high contents of glutamic acid, arginine and aspartic acid, and extremely low contents of cystine and methionine. The amino acid score of albumin, globulin, prolamin and NaOH soluble (glutelin fraction) fractions were 51.4,22.9,57.5 and 17.1, respectively, based on the FAO/WHO “provisional scoring pattern”. Albumin fraction was separated into six fractions (F-I, F-II, F-III, F-IV, F-V and F-VI) by gel filtration on Sephadex G-100. F-V was a main fraction and showed at least ten bands in polyacrylamide gel electrophoresis.