Emerging Health Benefits from Cocoa and Chocolate

Abstract

73 CHOCOLATE AND COCOA have recently become the objects of increased scientific research, mainly because of their interesting phytochemical composition. They are extremely rich in flavonoids, similar to those in red wine and green tea. These compounds may confer health benefits. Cocoa and chocolate are plant foods produced from cacao beans, the seeds of Theobroma cacao. Their production involves fermentation, drying, roasting, and grinding of the beans, resulting in an intermediate product called “cocoa mass.” To make chocolate, sugar is added to the cocoa mass, and the mixture is further processed. In the production of cocoa powder, the majority of the fat is removed. The way in which the cacao beans are processed greatly influences the composition of the final products. Specifically, fermentation and treatment with alkali both reduce the flavonoid content of the final product (Osakabe et al., 1998; Ziegleder et al., 1983). The chemical composition of the cacao bean has been well-characterized. In whole beans, 50–57% of the dry weight is lipid, or cocoa butter. The remaining fat-free mass is about 20% protein, 16% starch, 26% fiber, 5% ash, and 33% other components (Aremu et al., 1995). Cocoa is rich in minerals, particularly iron, copper, and magnesium, although little is known about their bioavailability. Cocoa butter is made up of about 34% stearic acid (18:0), 34% oleic acid (18:1), 25% palmitic acid (16:0), and 2% linolenic acid (18:3) (Otton, et al., 1998). In spite of its high saturated fat content, chocolate does not appear to raise cholesterol levels in normal humans (Kris-Etherton et al., 1993, 1994). This is likely because the major saturated fatty acid is stearic (18:0), which is neutral with respect to blood lipids (Yu et al., 1995). In fact, evidence is accumulating that flavonoid-rich chocolate may actually help lower the risk of cardiovascular disease because of the bioactivity of certain procyanidins. In whole, unprocessed cacao beans the polyphenol content is about 15% of the dry weight (Kim and Keeney, 1984). About 60% of the polyphenols are in the form of procyanidins, mostly ( 2 )epicatechin (EC) and ( 1 )catechin (Porter et al., 1991). Although some of the polyphenol content is lost during the fermentation process, cocoa powder still contains 1–2% EC and ( 1 ) catechin by weight (Osakabe et al., 1998). The unusual factor about the procyanidins in cocoa, as compared to those in tea and wine, is that they include many large oligomers. In both cacao beans and dark chocolate, oligomers with as many as ten subunits have been identified (Hammerstone et al., 1999). There is a large body of literature on bioactivity of various flavonoids. Of these, quercetin is one of the most common flavonoids in foods and has been studied the most extensively. Quercetin constitutes only a small fraction of