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

Andrea K. Stone, Anna Karalash, Robert T. Tyler, Thomas D. Warkentin, Michael T. Nickerson
Food research international 2015 v.76 pp. 31-38
alkali treatment, binding properties, chemical precipitation, cultivars, emulsions, foaming, foaming properties, foams, food industry, hydrophobicity, meat, oils, pea protein, peas, protein isolates, protein solubility, water holding capacity
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 (~70%) resulted in higher protein recoveries then MP (~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 (~89%) and MP isolates the lowest (~46%). Salt-extracted isolates had the highest oil holding capacities (5.3g/g) and the lowest water holding capacities (0.3–2.6g/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 (~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.