Improvement of solubility and functional properties of wheat bran fibers by ozone treatment

Wheat Bran (WB) components have multiple beneficial properties for human health. Physical, Chemical and biological treatments are used to improve WB physicochemical properties or extract WB bioactive components, but they can have drawbacks (cost, conditions, scalability). In this study an attempt was made to investigate the effect of ozone treatment on the physicochemical and functional properties of WB to further improve its nutritional and health benefits. Ozone treatment was carried out on a semi-industrial pilot scale with different O3 consumption levels ranging from 3 to 24 g/kg of WB. WB structural characterization was carried out using spectroscopy (FT-IR) and microscopy (SEM) analyses. WB fiber molecular effect was studied using fractionation analysis. Composition and functional properties (antioxidant power, binding capacities, inhibitory activities) were also assessed. As expected, ozone treatment did not impact WB structure. However, ozonation significantly increased the soluble dietary fiber content in WB by 32-67% indicating transformation of insoluble hemicelluloses. This was likely due to the ability of ozone to oxidize phenolic acids and to cleave β-glucans glycosidic bond. This reduces WB fiber molecular weight. Ozone shows major positive effects on WB functional properties by improving cholesterol adsorption capacity or α-amylase and α-glucosidase inhibitory activities. As conclusion, ozone could be a good candidate for the optimization of WB physicochemical and functional properties without altering its macromolecular structure. Furthermore, it is a green process that offers greater scalability for industrial applications compared to other treatments, enabling its incorporation in a wide range of food products.