Substitution of wheat starch with non-wheat starches and cross-linked waxybarley starch affects sensory properties and staling of Arabic bread

Substitution of starch from barley, corn, oat, potato, rice or sorghum for prime wheat starch in the formulation of Arabic bread resulted in breads wi th significantly (P < 0.05) different textural attributes from regular whea t bread except for barley starch. Substitution of waxy barley starch (957 g kg(-1) amylopectin) for wheat starch (279 g kg(-1) amylopectin) resulted i n bread that was not significantly different from regular wheat bread when assessed in the fresh state. However, upon aging, the waxy barley starch-co ntaining bread staled at a significantly (P < 0.05) faster rate than regula r wheat bread. Breads made with waxy barley starch cross-linked with 50, 20 0 or 500 ppm phosphorus oxychloride showed higher enthalpy of melting (Delt a H) upon aging and staled faster than the bread formulated with waxy barle y starch. These findings suggest that amylopectin retrogradation is one of the determinants of Arabic bread staling and that cross-linking promotes re crystallisation of amylopectin, possibly by keeping the polymer chains in c lose proximity. The rate of staling in breads formulated with cross-linked waxy barley starch decreased with increasing levels of cross-linking, possi bly owing to restrictions in the degree of starch swelling. (C) 1999 Societ y of Chemical Industry.