Effect of grape pomace usage in chocolate spread formulation on textural, rheological and digestibility properties

In this study, dried grape (Cabernet sauvignon) pomace (DGP) as a by-product of wine production was used in the chocolate spread (CS) instead of various amounts of sugar and milk originated powders (MOP; skimmed milk and demineralized whey powder 1:1, w/w). The formulations of CS samples were determined using mixture design method. The sugar, MOP and DGP concentrations changed between 35 and 50, 0.066-8.000 and 0.23-15 g/100 g, respectively. According to the results, the consistency coefficient (K) and flow behavior index values of CS samples changed between 8.10 and 28.50 Pas.s(n) and 0.52-0.71, respectively. In addition, firmness and spreadability parameters were determined between 0.80-1.42 N and 2.15-4.24 N mm, respectively. Total phenolic content in CS samples ranged from 3415 to 13,754 mg GAE/kg and their digestibility ranged between 25% and 84%. Also, the digestibility of resveratrol was determined between 47.6% and 95.7% at different DGP concentrations. All of the established models successfully described the relation with R-2 values higher than 0.800. Textural and rheological parameters as well as sensory characteristics of the samples indicated that DGP may be used as a healthy and low-cost ingredient in CS formulation to partially substitute sugar and MOP.