the effect of replacing the cocoa powder with coffee silver skin on physical, textural and sensory properties of dark chocolate

this research aims to assess the physicochemical properties, image features, textural and sensory qualities of dark chocolate made using coffee silver skin as a cocoa powder replacement which was substituted for 25%, 50%, 75% and 100% of the cocoa powder (by weight) in chocolates. the results indicated that there was significant differences between the chocolates prepared using 100% coffee skin and the control, for moisture content (p<0.05). chocolates with 75% replacement had significantly the highest glossiness and hardness. moreover, image analysis showed that l* value increases significantly with increasing coffee skin ratio. this replacement had also negative significant effect on the melting point, taste, bitterness and sweetness but the influence of coffee skin substation was not meaningful on the particle size, adhesiveness, mouth feel and overall acceptance of samples (p<0.05). regarding to high correlation between results of image texture data and instrumental as well as sensorial properties, image analysis could be applied as a rapid, accurate and non-destructive method for texture evaluation of chocolate.