M.A. Thesis:

Study of sugar replacement with grape syrup on the physico-chemical٫ microbial and sensory properties of cocoa chocolate

In this research, syrup was produced from royal grape. Since the major sugars of grape syrup are simple sugars. Replacing it with sugar in the dark chocolate formulation reached less than 10%. At higher levels, the material adhered to Balmill's body. For this reason sugar has been reduced from chocolate formulation and to that extent only in the central dark chocolate, Grape syrup was replaced at 25 and 50% levels. Then the physicochemical, sensory and microbial characteristics of the samples were measured. The results showed that increasing the sucrose replacement with grape syrup in the central dark chocolate , the pH of the samples decreased compared to the control, but moisture, sugars and insoluble ash in dry matter significantly increased, and in the total fat, and fatty acidity were not observed different. In the section of microbial tests, replacing sugar with grape syrup did not cause the activity of microorganisms, because of Escherichia coli, Enterobacteriaceae, yeast and mold were negative in all samples. In the sensory section, with increase in the sugar substitution by grape syrup, caused the Poorer color intensity and polish, Lower taste, harder texture, higher adhesion, higher fatty, Longer disappearance and lower overall acceptance. But not observed change in the odor, roughness of the texture and the cold sensation. The results of adding orange peel powder to chocolate as a natural flavoring showed that No significant change was observed in chemical properties such as: moisture, fat, simple sugars and pH; Only the percentage of insoluble ash increased. There were no changes in the microbial section. Because different samples were negative for Escherichia coli, Enterobacteriaceae, mold and yeast. In the sensory section, Better color intensity and polish, smell much favorable, the taste of pleasant , Less texture adhesion, Fatty tissue is weaker, Feeling more cold, Higher overall acceptance, but the texture of the sampless became harder.

Keywords: Dark Chocolate ; Grape syrup ; Orange Peel Powder ; Chemical, Sensory and Microbial Properties