Hull-less barley pearling fractions: Nutritional properties and their effect on the functional and technological quality in bread-making

Breads enriched with hull-less barley (HLB) have been characterized. An HLB cultivar was sequentially pearled, and the fractions were analyzed for their bioactive components. Ash, proteins, dietary fibre (DF) and total antioxidant activity (TAA) decreased from the external to the internal layers, while β-glucans showed an inverse trend. Two functional ingredients were selected: an external fraction (5-15% w/w) and a debranned inner fraction (25-100%). Five mixtures of refined commercial flour, with increasing replacement with pearled HLB fractions, were used for each ingredient to prepare bread. The addition of the external layers led to a higher enrichment in ash, proteins, DF and TAA, and showed significant changes in the rheological parameters, with detrimental effects on the bread volume and texture. At a 10%-substitution level, the technological properties were acceptable and similar to those shown by the control, while the nutritional value was significantly improved. Conversely, the addition of the inner kernel fraction was also successfully employed at high replacement levels, with only a few physical and rheological changes. This ingredient led to a lowering of the improvement in the antioxidant compounds, but it clearly enhanced the DF and β-glucan contents in the bakery products.