Fractionation of industrial solids containing barley husks in aqueous media

Lignocellulosic materials, particularly the ones of residual nature generated in agricultural and industrial activities, represent a renewable, abundant and cheap source of raw materials for multiple purposes. Barley husks belong to this type of materials. Aqueous fractionation of a solid byproduct from malting industries (denoted MSW), mainly made up of barley husks, leads to a liquid phase containing bioactive components (oligosaccharides derived from hemicelluloses with prebiotic activity and low molecular weight phenolics with antioxidant activity) and to a solid phase containing cellulose and lignin as major components. Antioxidant compounds can be separated from fractionation liquors by physicochemical processing, providing a practical approach to sustainable development. Based on experimental data, the solubilization of MSW hemicelluloses is assessed in terms of kinetics, composition, material balances and properties of the isolated fractions. The nature, refining and properties of the antioxidant compounds extracted from liquors obtained by non-isothermal processing of MSW are discussed on the basis of experimental results.