Effects of sorghum flour addition on chemical and rheological properties of hard white winter wheat

Abstract

This study was carried out to investigate the chemical and rheological properties of different blends prepared using hard white winter wheat (HWWW; Triticum aestivum Desf.) and whole or decorticated sorghum (Sorghum bicolor). Whole and decorticated sorghum were used to replace 5, 10, 15 and 20% of wheat flour. Wheat samples had higher protein, moisture and calcium values and lower fat, ash, carbohydrates, iron and phosphorous values compared to whole and decorticated sorghum flours. Decortication of sorghum grains decreased moisture, ash, fat, crude protein, iron and phosphorous content, but increased carbohydrate content. Farinogram properties such as dough water absorption, development time and stability and Farinograph quality number decreased as the amount of substituted sorghum increased; whereas mixing tolerance index increased. Moreover, at fixed gluten levels, as sorghum flour increased in the blend, wet gluten, dry gluten and gluten index decreased. Increasing sorghum in the blend also decreased energy, resistance to extension and extensibility of the dough, but contributed to an increase in the ratio of resistance to extensibility. Furthermore, as fermentation time increased, energy, resistance to extension and the ratio number of energy to extension increased, whereas extensibility decreased.© Maxwell Scientific Organization, 2013.