357 Characteristics of prime and tailings starches isolated from waxy and non-waxy barley.

L. T. NGUYEN, Z. Czuchajowska, and B.-K. Baik. Department of Food Science and Human Nutrition, Washington State University, Pullman, WA 99164-6376.

Barley grains from one covered non-waxy and two hull-less waxy cultivars were abraded and milled to different streams of flour using a roller mill. Prime and tailings starches were isolated and purified from the break flour. Differences in chemical composition, physical characteristics and thermal behavior of prime and tailings starches were evaluated. Yields of prime starches ranged from 38.8% to 43.3% and those of tailings starches were less than 8%. Ash content was similar among prime and tailings starches, ranging from 0.10% to 0.18% in all three cultivars. Protein content of both prime and tailings starches was less than 0.41%; however, tailings starches had consistently higher protein content than prime starches in each cultivar. X-ray diffraction peaks for amylose-lipids complex of prime and tailings starches were similar in the non-waxy barley and detected only in tailings starches of the two waxy barley cultivars. Amylograph peak temperature of prime starches was 93 C for the non-waxy barley and 66 C to 67 C for the waxy barley cultivars. The peak viscosity was 840 BU for the non-waxy prime starch and 2265 BU and 2320 BU for the waxy barley cultivars. Endothermic enthalpy values for starch gelatinization were higher in prime starches than in tailings starches in all three cultivars, while enthalpy values for amylose-lipids complex were higher in tailings starches.