Coffee silverskin as a source of dietary fiber in bread-making: Optimization of chemical treatment using response surface methodology

Nowadays, there is a growing demand from consumers for baked products with lower caloric density and higher levels of dietary fiber. In the present study, the response surface methodology was used to determine the optimum treatment of coffee silverskin (CS) with alkaline hydrogen peroxide that gave the best quality, shelf life, sensory and image properties for Barbari flat bread. Contact time, solution portion and particle size were considered components of the chemical treatment. The most compatible model among mean, linear and quadratic expressions was fitted to each response and the regression coefficients were determined using least square method. The optimum condition was found to be a chemical process containing mixing time of 1 h, solution portion of 4.77 and particle size of 116.41 μm when desirability function method was applied. There was a good agreement between the experimental data and their predicted counterparts. Results showed that alkaline hydrogen peroxide CS might be useful as an ingredient for reducing caloric density and increasing dietary fiber content of bread.

► The coffee silverskin (CS) was used as a dietary fiber source in flat bread. ► Optimization of chemical treatment of coffee silverskin was determined. ► The proposed methodology was applied to determine CS and bread properties. ► There were good correlations between quality, shelf life, sensory and image parameters.