Extraction and Characterization of Bean Protein Isolates Grown in High Altitude Northern Himalayas

Abstract

The purpose of the research was to optimize the extraction process for navy bean protein isolation and study their properties using different characterization methods. Navy beans were dehulled and utilised for protein extraction. The beans were soaked in Milli-Q TM water (1:5 wt seed: volume water) for 16 hours at 25 °C. The outer layers were removed by rubbing the beans between hands and the seed coats were separated and taken off. For the isolation of bean protein, alkaline and isoelectric precipitation was used and response surface methodology was employed to further optimise the parameters. The isolates were evaluated for proximate analysis, functional, thermal, structural properties and particle size analysis. The extraction and optimisation of navy bean protein isolates were investigated using response surface methodology; under optimal conditions (120 min extraction time, 48 °C extraction temperature, 18.7 mL/g solvent/solute ratio and pH 10.5) where the maximum protein content (24.16 ± 0.2 % db), extraction yield (20.21 ± 0.01%), and protein recovery yield (57.53 ± 0.24%) were obtained. The nitrogen solubility index (NSI) of extracted isolates was 81%. Further, the DSC curves indicate that the denaturation temperature was much higher which showed higher thermal resistance and also the differences in secondary structure were evident on circular dichroism spectra of the soluble extracts