مقایسه ی ویژگی های فیزیکوشیمیایی نان گندم حاوی جو بدون پوشینه با نان گندم حاوی جو پوشینه دار

Abstract

barley is a kind of cereal that contains high amounts of β-glucan. β-glucan is a major component of soluble fiber implicated in hypocholesterolemia, hypoglycemia, diabetes and heart attacks. Investigations show that hull-less barley has more β-glucan than hulled barley. In this study the physical and chemical properties of hull-less barley (EHDS 18), wheat (zarrin) varitiese, barley flour, and the impact of substitution of hull-less and hulled barley flour to wheat flour at 20, 35, and 50% levels on the physicochemical properties and the staling of bread were carried out. the staling of bread, was analyzed by Instron texture analyzer machine, colorimetry, by hunterlab and volume by rapeseeed displacement. The results of phisicochemical tests showed that the properties of hull-less barley is significantly (p<0.05) different from the tested wheats. Hull-less barley has lower hectoliter weight, falling number and gluten and in contrast, higher moisture, protein, fiber and thousand seed weight, in compared with wheat. The results of staling tests that has done in four times, 0, 24, 48 and 72 hour showed that with substitution of hull-less barley flour with wheat flour the rate of staling would increase, but there was no significant difference between the rate of staling in breads with 20% and 35% of hull-less barley flour. The rate of staling in hull-less barley bread is lower than hulled barley breads. The volume of hull-less barley bread is significantly highter than hulled barley breads. Among all the breads that was produced, minimum staling was observed for the mixture of 80% of wheat flour and 20% of hull-less barley flour, so we can choose this formulation as the best one for bread production, although the 35% of hull- less barley flour, did not disturbed the quality of breads. Keywords: Hull-less barley, Hulled barley, β-glucan, Bread, Physicochemical properties, Staling