BACKGROUND By-products generated during the processing of plant food can be considered a promising source of dietary fibre as a functional compound. The dietary fibre composition, soluble sugars and antioxidant activity of the extractable polyphenols of pea and broad bean by-products have been analysed in this study.
RESULTS: Total dietary fibre using AOAC methods plus hydrolysis (broad bean pod: 337.3 g kg−1; pea pod: 472.6 g kg−1) is higher (P < 0.05) in both by-products than with the Englyst method (broad bean pod: 309.7 g kg−1; pea pod: 434.6 g kg−1). The main monomers are uronic acids, glucose, arabinose and galactose in broad bean pods. However, pea pods are very rich in glucose and xylose. The soluble sugars analysed by high-performance liquid chromatography in both by-products have glucose as the most important component, followed by sucrose and fructose. The ferric reducing antioxidant power (broad bean pod: 406.4 µmol Trolox equivalents g−1; pea pod: 25.9 µmol Trolox equivalents g−1) and scavenging effect on 2,2-diphenyl-1-picrylhydrazyl radical (EC50 of broad bean pod: 0.4 mg mL−1; EC50 of pea pod: 16.0 mg mL−1) were also measured.
CONCLUSIONS: Broad bean and pea by-products are very rich in dietary fibre, particularly insoluble dietary fibre and their extractable polyphenols demonstrate antioxidant activity. Therefore they might be regarded as functional ingredients. Copyright © 2011 Society of Chemical Industry