Progressive pearling of barley kernel and application to production of functional breads

A strategy to maximise the health benefits of wheat-based products could be to enrich refined flour with fractions of external kernel layers, obtained using grain dry-fraction technologies. Beside the chemical characterization of different fractions obtained from the pearling of two varieties of barley (cv Mona, naked, two-row; cv Trasimeno, hulled, two-row), the principal aim of this work was i) the identification of the most performing fractions useful as ingredients for bread, following an approach previously applied to wheat bread (Sovrani et al. 2013). Moreover, ii) the final products were characterized in order to study the influence of these barley fractions under both nutritional and technological profile. Considering the different composition of pearled barley fractions (external fractions are richer in antioxidants and insoluble fibre than internal kernels, which, on the contrary, contain most β-glucans), two different fractions from cv Mona were employed, specifically the most external (corresponding to the 0-5% of kernel weight) and the most internal (residual 75% weight) fractions. About the Trasimeno variety, the sequential pearled fraction corresponding to 15-25% weight of barley kernel was selected. Three different series of substituted flours were obtained (substitution percentages: 0, 5, 10, 15, 20 and 25%) and used to prepare bread. All the samples were analysed for the chemical composition (moisture, proteins, ashes, fibre, β-glucans and total polyphenols), the antioxidant activity, the rheological properties (Mixolab® parameters) and the physical bread properties (volume, crust colour, instrumental crunchiness and crumb texture profile analysis parameters). As expected, the use of enriched flours improved the functional properties of the breads, in accord with the original properties of the barley fractions. Up to 10%-substitution the bread rheological properties were not affected, even if a significant reduction of final volume of bread was observed, when compared with not-enriched bread.