Hydrophobic bioactive constituents of cinnamon bark as inhibitor of polyphenol oxidase from Musa acuminata ‘Mas’ peel.

The rich content of hydrophobic bioactive constituents in cinnamon bark is foreseen as a potential anti-browning inhibitor. In this study, hexane extract of cinnamon bark was examined along with aniseed, clove, coriander, cumin, dried tangerine peel and Sichuan pepper on antioxidant, antibacterial and anti-tyrosinase activities. Antioxidant and antibacterial do inhibit oxidation of browning intermediate products and prevent enzymatic browning activation as a defence response against bacteria invasion, respectively. Clove extract was the best radical scavenger (267.46 ± 17.87 mg AA/g) while Sichuan pepper extract was an excellent ferrous ion chelator (CEC50: 0.07 ± 0.01 mg/mL). Meanwhile, cinnamon bark extract was very effective at inhibiting the growth of selected bacterial with minimum inhibitory concentration ranged from 0.25 to 0.50 mg/well. Anti-tyrosinase activity measures the spice capability to supress browning through tyrosinase inhibition. Cumin, cinnamon bark and dried tangerine peel extracts had comparable anti-tyrosinase activities with IC50 values ranged from 1.02 ± 0.13 to 2.39 ± 0.21 mg/mL. The good antibacterial and anti-tyrosinase activities of cinnamon bark extract was furthered examined on Musa acuminata ‘Mas’ peel polyphenol oxidase inhibition, where it exhibited mixed inhibition with IC50 value of 1.19 mg/mL. Cinnamon bark extract is potentially used as natural anti-browning additive that also compatible with most of the active packaging materials.