Effect of hot aqueous ethanol treatment on anti-nutritional factors, protein denaturation and functional properties in raw pea and pea protein isolate

Abstract

The effect of hot aqueous ethanol treatment on several nutritionally relevant mainly protein-related parameters in raw peas (var. Solara) and ultra-filtrated pea protein isolate was examined. Of all test samples, water absorptive capacity (WAC), weight loss and protein loss owing to the processing were determined. All test samples, the raw peas and the pea protein isolate were analysed for nitrogen content, protein dispersibility index (PDI), trypsin inhibitor activity (TIA), lectin content, protein composition and antigenic proteins. The hot aqueous ethanol treatment resulted in a denaturing of pea protein accompanied by a reduction of activity of anti-nutritional factors and changes in functional properties in both the raw pea and the pea protein isolate. No effect on protein composition or antigenicity was observed. The treatment with aqueous ethanol of 55 vol.% at a temperature of 80°C resulted in the largest reduction in PDI, TIA, lectin content and the highest values for weight loss, protein loss and WAC. Higher ethanol concentrations and lower treatment temperatures resulted in smaller reductions in PDI, TIA and lectin content, lower values for WAC and lower weight and protein losses. As optimal treatment, which means a treatment resulting in a clear reduction in activity of anti-nutritional factors and small weight and protein losses, a treatment with aqueous ethanol of 65 vol.% at a temperature of 65°C was suggested.