Technological and nutritional aspects of milk chocolate enriched with grape pomace products

Abstract

The French paradox is the observation of low heart disease death rates despite high intake of cholesterol and saturated fat, possibly related to the consumption of red wine containing polyphenols. Those are also found in pomace and affect health as radical catchers inhibiting cancer, inflammations and arteriosclerosis. European cocoa regulation allows incorporating up to 40% of added foodstuffs into chocolate, so grape pomace can be used. Cocoa itself is known as a very good source of phenolic compounds, and consequently dark chocolate is considered to have similar health benefits as red wine. Milk chocolates contain only little fat-free cocoa dry matter; therefore, grape pomace is considered most beneficial here. Entire pomace or flour from seeds have been tested to evaluate technical aspects as well as the impact on chocolate properties like particle size distribution, flow properties, total phenol content, antioxidative capacity and sensory perception. Initial trials revealed that additional drying and also pre-grinding was necessary before pomace can be used as an ingredient. Various samples were produced by the coarse conching process, which uses a ball mill for size reduction below 30 µm. A difficulty arises when some tough particles slip through without being properly ground; D99-values can be used to better control this issue. Grape pomace contains almost as many polyphenols as cocoa liquor, so it can serve as a substitute. Its content and thus quality depends on gentle drying. Finally, adding, e.g., just 3.5% was able to significantly increase the polyphenol contents of milk chocolate.