Functional attributes of pea protein isolates prepared using different extraction methods and cultivars

Protein isolates prepared from three pea cultivars by alkali extraction/isoelectric precipitation (AE-IP), salt extraction-dialysis (SE) and micellar precipitation (MP) were assessed for their surface (charge, hydrophobicity) and functional (water/oil holding capacity, solubility, foaming and emulsion capacities/stabilities) properties. Isolate yield was greatest for SE, followed by AE-IP and then MP. Salt extraction and AE-IP (similar to 70%) resulted in higher protein recoveries then MP (similar to 31%). Surface charge was similar for all isolates whereas hydrophobicity was greatest for AE-IP isolates. Overall, differences in functionality between cultivars for a particular extraction method were minimal. Salt-extracted isolates exhibited the highest protein solubility (similar to 89%) and MP isolates the lowest (similar to 46%). Salt-extracted isolates had the highest oil holding capacities (5.3 g/g) and the lowest water holding capacities (0.3-2.6 g/g). Foaming properties were affected by both extraction method and cultivar, however, in general SE isolates tended to have better foaming capacities whereas AE-IP isolates produced more stable foams. Emulsion capacity was greater for SE isolates than AE-IP isolates. All isolates displayed high emulsion stability (similar to 98%). The prepared protein isolates show potential as a plant protein alternative to soy for the food industry, with the exception of possibly meat applications due to the isolates' poor water binding properties relative to soy. (C) 2014 Published by Elsevier Ltd.