Effect of antioxidants, color and sensory atributes of different sorghum brans in model baking systems

Abstract

The effects of substitution of cocoa with sorghum bran in brownies were evaluated. Particle size, color, phenol content, tannin content and antioxidant activity of sorghum brans were evaluated and compared to cocoa before and after the roasting process. Cocoa was substituted in levels of 25% and 50% with non roasted and roasted sorghum brans. Color, phenol content, tannin content and antioxidant activity, and texture of brownies containing sorghum bran as a cocoa extender were evaluated. A hedonic scale for texture, color, taste, aroma and overall acceptability of brownies was used for sensory evaluation of brownies. Objective texture test of brownies was evaluated with Texture Profile Analysis and color was evaluated objectively using the CIEL*a*b* scale. Color of sorghum brans similar to cocoa were achieved by adjusting decortication of sorghum, roasting time, roasting temperature, moisture content and fructose content levels. Brans with 10% decortication had lower L* and a* values; Increase in roasting time, roasting temperature and moisture content, decreased L* values. Higher phenol content, antioxidant activity and tannin content was obtained with sorghum brans with 10% decortication roasted at lower temperature and lower moisture content. Colors of brownies containing sorghum brans were similar to sample with 100% cocoa. Brownies with substitution of cocoa with 25% of roasted sorghum bran had higher phenol content, antioxidant activity and tannin content than other samples with sorghum bran. Total dietary fiber of brownies with 100% cocoa was similar to those brownies containing bran with 10% decortication. Texture, aroma and overall acceptability of brownies containing sorghum bran and 100% cocoa had no significant difference. Color attribute of brownies with 0% substitution and 25% substitution with 10R25 bran treatment had no significant difference. Overall, sorghum bran could be an economical option for use as a cocoa extender in brownies and other similar bakery products.