Effect of roasting on flavonoids, phenolics, and antioxidant activity of industrial-pulped and fermented cocoa beans
Bernard Kwabena Asiedu, Emmanuel Ohene Afoakwa, Crossby Osei Tutu, Rexford Obeng, Nii Korley Kortei, Papa Toah Akonor, Agnes Simpson Budu, Firibu Kwesi Saalia
Abstract
• Depulping and roasting affect polyphenols, flavonoids, and antioxidants in cocoa. • More depulping lowers flavonoids, antioxidants but increases polyphenol content. • Moderate (120 °C, 30 min) and LTLT (110 °C, 60 min) roasting retain flavonoids. • Moderate roasting gives the highest antioxidants, followed by LTLT roasting. The extent to which roasting of depulped cocoa beans at varied roasting intensities influences the total polyphenolic content, total flavonoid content, and DPPH scavenging capacity of cocoa liquor remains underexplored. This study investigated the effect of mechanical depulping and roasting intensities on these parameters in Ghanaian cocoa beans. A 3 × 3 full factorial design was employed, with depulping levels (0 %, 50 %, and 100 %) and roasting conditions (110 °C for 60 min, 120 °C for 30 min, and 135 °C for 10 min) as the principal factors. Cocoa beans were depulped mechanically, fermented for six days, dried at 55 °C to a moisture content of 7, 8 %, roasted, deshelled, and milled into cocoa liquor. The results showed that roasting intensity and mechanical depulping significantly influenced the studied parameters. Cocoa liquor obtained from mechanically depulped beans exhibited a higher total polyphenol content but lower flavonoid content and antioxidant capacity. Moderate roasting (120 °C for 30 min) and low-temperature, long-time (110 °C for 60 min) roasting processes preserved more flavonoids and antioxidant activity than high-temperature, short-time (135 °C for 10 min) roasting. These findings highlight the importance of optimizing depulping and roasting conditions to balance the retention of bioactive compounds and antioxidant properties in cocoa liquor.