Composition and utilization of barley pearling by-products for making functional pastas rich in dietary fiber and β-glucans

Pearling by-products and the pearled products of two commercial stocks of hulled barley, pearled according to an industrial process consisting of five consecutive pearling steps, were analyzed for beta-glucans, dietary fiber (total, soluble, and insoluble), protein, lipid, ash, and digestible carbohydrate. The data showed that the pearling flour fractions, abraded in the fourth and fifth hullers, contained interesting amounts of beta-glucans (3.9-5.1% db) from a nutritional point of view. These fractions were subsequently enriched in beta-glucans using a milling-sieving process to double beta-glucan content (9.1-10.5% db). Functional pastas, enriched with beta-glucans and dietary fiber, were produced by substituting 50% of standard durum wheat semolina with beta-glucan-enriched barley flour fractions. Although darker than durum wheat pasta, these pastas had good cooking qualities with regard to stickiness, bulkiness, firmness, and total organic matter released in rinsing water. The dietary fiber (13.1-16.1% wb) and beta-glucan (4.3-5.0% wb) contents in the barley pastas were much higher than in the control (4.0 and 0.3% wb, respectively). These values amply meet the FDA requirements of 5 g of dietary fiber and 0.75 g of beta-glucans per serving (56 g in the United States and 80 g in Italy). At present, the FDA has authorized the health claim "may reduce the risk of heart disease" for food containing beta-glucans from oat and psyllium only.