Progressive pearling of barley kernel: a new technological approach for the production of bioactive-rich ingredients dedicated to functional bakery products.

“Food design” using functional ingredients is becoming a new frontier in food technology and nutrition area. Cereals are fundamental crops for human nutrition; beside the carbohydrate nutritional profile, largely represented by starch, these foods are rich in bioactive compounds like prebiotic fiber, alchylresorcinols, lignans and other polyphenols with antioxidant capacity, and beta-glucans. Progressive pearling, leading the removing different percentages of hull and bran parts from the seed, is an interesting approach useful to obtain new ingredients rich in bioactive compounds (Sovrani et al., 2012; Sovrani et al., 2013). Beside the chemical characterization of different fractions obtained from the pearling of three varieties of barley (cv Mona, hulless, two-row; cv Trasimeno, hulled, two-row and cv Ketos, hulled, six-row), the principal aim of this work was i) the identification of the most performing fractions useful as ingredients in bread and sweet baked products. Moreover, ii) the baked products were completely chemically characterized in order to study the influence of these barley fractions under both nutritional and technological profile. Some of the pearled fractions from barley were characterized by a high content of β-glucans and/or great antioxidant capacity; these fractions should be considered as functional ingredients useful to fortify conventional wheat flours. Among them, the sequential pearled fraction corresponding to 15-25% weight of barley kernel (Trasimeno variety) was selected to prepare enriched flours. This fraction contained 3.29 g/100 g (dry weight, d.w.) of β-glucans, 24.7 g/100 g d.w. of total fiber, and was characterized by an antioxidant capacity of 114 mmol Trolox eq/Kg d.w. (measured as ABTS radical scavenging activity, QUENCHER method). The substitution of conventional wheat flour with this selected fraction was performed at different percentage levels and the novel fortified flours were used for bread-making. 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. In this case, the final recipe of the bread was significantly improved, reaching 0.52 g/100 g d.w. of β-glucans (about 3.5 times the content in the refined bread not substituted), a total dietary fibre content of 5.89 g/100 g d.w, and a significantly improved antioxidant capacity (16.2 mmol Trolox eq/Kg d.w.). Beside this application, the residual 75% fraction (weight) obtained from the pearling of Mona variety, a fraction particularly rich in β-glucans (5.24 ± 0.23 g/100 g, dried weight), has been used to improve nutritional profile of a sweet baked product. All these features will be the object of this oral communication, confirming the usefulness of progressive pearling process and refreshing new data about the technological processing of barley derived products and their use in baking process.