Antioxidant, Antityrosinase Activity and Physicochemical Properties of Manufactured Chocolates in Taiwan Affected by Roasting Treatments

Abstract

Roasting is an important step in cocoa processing that affects the functional and organoleptic properties of chocolate products. The effect of roasting treatment on antioxidation, antityrosinase activity, and physicochemical properties of 12 manufactured chocolates from Southern Taiwan fermented cocoa beans was investigated. The cocoa beans were roasted at different fixed temperatures ranging from 90 to 150°C for different time duration 15-35 min. The results showed that more severe thermal treatment decreased the contents of total phenolic compounds and proanthocyanidins, from the highest 20.57± 0.86mg GAE /g defatted chocolate and 9.20±0.49 mg CyE /g defatted chocolate to the lowest 11.48±0.23 mg GAE /g defatted chocolate and 4.14±0.41 mg CyE /g defatted chocolate, respectively. Meanwhile, roasting treatment also reduced DPPH and ABTS radical scavenging activities in temperature and time-dependent manners. In addition, the low-roasting chocolate revealed the potent inhibitory action on mushroom tyrosinase activity at 2.5 mg/g defatted chocolate. However, chocolate produced from beans roasted at 130°C for 25 min was ranked the highest consumer acceptability in the sensory evaluation. Taken together, the optimization of cocoa bean roasting conditions can improve the health benefits of chocolate, while the low-roasting chocolate acts as a potent candidate for tyrosinase inhibitors.