Development of a Novel Chocolate Utilizing Mushroom Fermentation and Associated Changes in Beneficial Components

This study investigated the secondary fermentation of cocoa beans using mushrooms to further improve the quality of beans. Cocoa beans were fermented using 42 species of basidiomycetes and ascomycetes. Mycelial growth was observed in 29 strains. When 75% cocoa chocolate was prepared using the cocoa beans in which mycelial growth was observed, theobromine concentration was higher in 17 strains compared with the control. Furthermore, caffeine concentration was similar to or lower than the control in all strains. Chocolate produced using cocoa beans fermented with particularly <i>Polyporus arcularius</i>, <i>Peziza vesiculosa</i>, and <i>Urnula craterium</i> exhibited significantly higher theobromine concentrations. Compared to the control theobromine concentration of 7.53 mg/g, <i>P. arcularius</i> showed 9.25 mg/g, 9.13 mg/g for <i>P. vesiculosa</i>, and 9.05 mg/g for <i>U. craterium</i>. Furthermore, the reducing sugar concentration and total polyphenol concentration increased, and the antioxidant activity was similar to or higher than that of the control. These results suggest that secondary fermentation using mushrooms could be used to develop chocolate characterized by high theobromine, low caffeine, and rich polyphenol content.