Evaluation of the Yeild, Protein Content and Functional Properties of Mungbean [Vigna radiata (L.) Wilczek] Protein Isolates as Affected by Processing

Abstract

The effect of processing on mungbean protein isolate yield, protein content and functional properties were evaluated. The functional properties evaluated were Water Absorption Capacity (WAC), Oil Absorption Capacity (OAC), Emulsion Capacity (EC) and nitrogen solubility. The protein isolate yield and protein content from the raw mungbean flour were 10.52 g protein/100 g flour and 87.56% respectively. Processing had significant (p<0.05) effect on the isolate yield, protein content and functional properties. The toasted flours yielded the highest protein isolates (10.68-8.48%), although there was progressive decrease in isolate yield as toasting time increased. Increase in sprouting time resulted to a significant (p<0.05) increase in isolate yield, however, no significant (p>0.05) decrease was observed for the protein content. Increase in boiling time markedly reduced both isolate yield (6.41-5.80%) and protein content (86.10-32.84%) respectively. The mungbean protein isolates from 60min boiled flour had the highest WAC (2.5 g/g), OAC (2.15 ml/g) and EC (22.16%) while the isolates from 90min toasted flour had the highest WAC (2.97 g/g), OAC (2.25 ml/g) and EC (18.92%). Isolates from 24 h sprouted flour gave the highest WAC (1.75 g/g), OAC (1.25 ml/g) and EC (10.96%). The functional properties of the mungbean protein isolates were significantly (p<0.05) improved by processing and the high solubility indicates its suitability for industrial application as protein supplements.