Physicochemical and textural properties of heat-induced pea protein isolate gels

Chemical and thermal properties of pea protein isolates (laboratory prepared or native; PPIn and commercial; PPIc) and textural properties of heat-set gels obtained from pea protein isolates were compared with homologous soy protein isolates (laboratory prepared, or native; SPIn and commercial; SPIc). The protein banding pattern resulting from electrophoresis separation confirmed the presence of predominant storage proteins of pea and soy seeds in the respective protein products. PPIc and SPIc had lower nitrogen solubility than their native counterparts, likely due to their denaturated state which was further confirmed by the absence of distinct endotherms in these commercial materials compared to the laboratory prepared ones. Addition of NaCl at 1.0-2.0% (w/w) to PPIn and SPIn slurries increased thermal transition temperatures for both proteins. The optimal conditions for formation of strong heat-induced gels from PPIc were 19.6% (w/w) protein content, pH 7.1, 2.0% (w/w) NaCl, and heating at 93 degrees C. SPIc gels prepared under the same conditions were stronger and more elastic than PPIc gels as denoted by texture indictors. (c) 2006 Elsevier Ltd. All rights reserved.