Biochemical studies of cocoa bean polyphenol oxidase

Abstract

A BSTRA C T Polyphenol oxidase (EC 1.14.18.1)

Polyphenoloxidase deactivation kinetics during ohmic heating of grape juice

“…Similar results were reported in a previous study where the maximum PPO activity was found at 70°C for 35 V/cm . The critical deactivation temperature of PPO was reported as 68°C in apple (Yemenicioglu, Ozkan, & Cemeroglu, 1997) and 45 and 60°C in cocoa (Lee, Lee, & Karim, 1991).…”

Separation and thermal characterization of ionically and tightly cell-wall-bound pectin methylesterase from cucumbers ( Cucumis sativus )

“…The TPME showed activation at 50, 55 and 57.5 7C, whereas no activation was observed for the IPME at the temperatures studied. The activation of enzymes during heat treatment has been reported by many workers for different enzymes [9,11,12] and attributed to the release of latent enzyme fractions [9]. 2 Heat inactivation of the ionically bound PME from cucumbers Fig.…”

Comparative Evaluation of Computational and Experimental Analysis of Polyphenol Oxidase from Cocoa (Theobroma cacao L.)

“…Therefore, it could be rightly predicted that cocoa PPO will has crystalline mass in the same range. This validates the molecular weight of 30kDa [9], 36.03kDa [10] from the SDS-PAGE of cocoa beans PPO enzyme, possibly of different cocoa species.…”

“…PPO activity is also implicated in the reduction of bitterness and astringency of cocoa flavor [8].However, the browning in cocoa is beneficial to some extent as it enhances the quality of the beverages through its forming flavorful products [5].The PPO of cocoa bean has been studied by several groups, showed that it lacked the hydroxylation properties and act only on odiphenols. Diphenolase activity is generally the most prevalent form of PPO in higher plants [5].Using catechol as substrate, the optimum pH of 6.8 [9], 5.8 [8], and optimum temperature of 45ºC with half life of 5mins, with molecular weight of 30kDa [9], has been reported. Putra et al [10] There are few sequences of PPO from cocoa that are available in the bioinformatics databases as at the time of this study.…”