Antioxidant Activity and in vitro Fermentation of Dietary Fiber Extracts from Durum Wheat Bran

Abstract

The aim of this paper was to select a dietary fiber of durum wheat bran among several types which have different functional and nutritional characteristics. The potential of antioxidant activity of soluble (SDF) and insoluble (IDF) dietary fiber has been evaluated. The suspensions were later fermented by Bifidobacterium and lactic acid bacteria strains to evaluate the effect of these fibers on the growth of these strains of bacteria. Wheat bran was hydrolysed in vitro using gastric and pancreatic enzymes. The soluble and insoluble fibers were obtained by precipitation with ethanol. All the bran extracts exhibited appreciable total phenolic content (1.50±0.095–1.02±0.25 mg gallic acid equivalent/g bran), total flavonoid content (Quercetin equivalent 0.52±0.012–0.46±0.19 mg/g bran) and DPPH radical cation scavenging activity (IC50 1.48±0.34–3.6±0.18 mg/g). Insoluble dietary fiber exhibited high antioxidant potential and significantly more than soluble dietary fiber. Among the four probiotic strains tested, Lactobacillus acidophilus showed in IDF media a higher maximum growth. For most of the tested strains, growth on the SDF was less than on IDF (p<0.05).