Effect of Cyclodextrins on Polyphenol Oxidation Catalyzed by Apple Polyphenol Oxidase

Abstract

In order to find nonsulfite antibrowning agents for the food industry, cyclodextrins (CD) have been tested. CD are able to form inclusion compounds with polyphenols and inhibition properties have been studied in model solutions containing one or two phenols and purified apple polyphenol oxidase (PPO). The dissociation constants (K D ) of a series of phenolic compounds with α-CD, β-CD and hydroxypropyl-β-CD have been determined both by enzymatic kinetic analysis and NMR experiments in solution with one phenol. Large differences have been found among the phenols tested resulting in wide variations in the inhibitory properties of CD. In the mixtures of two phenolic compounds, addition of β-CD can result either in a large inhibition, a slight inhibition, or even a slight activation of oxygen uptake, depending on the kinetic constants and of the phenols present in the solution. Moreover, since β-CD induced a modification of the balance of free substrates in a multiphenolic solution, the colors obtained after enzymatic oxidation catalyzed by PPO can also be modified in different ways by addition of β-CD as demonstrated on the 3 types of mixtures of two phenolic compounds that we have tested, namely chlorogenic acid / (-)-epicatechin, chlorogenic acid / (+)-catechin and 4-methylcatechol / caffeic acid.Enzymatic browning which occurs during handling, storage and processing of fruits and vegetables is mainly initiated by the enzyme polyphenol oxidase (odiphenol : oxygen oxidoreductase EC 1.10.3.1) or PPO (7, 2). The loss of cell integrity results in the decompartmentation of phenolic substrates and enzymes and then, in the presence of molecular oxygen, the oxidative production of colored quinones (3). Brown pigmentation following this enzymatic reaction and subsequent non enzymatic 0097^156/95/0600-0295$12.00/0

Retarding Oxidative and Enzymatic Degradation of Phenolic Compounds Using Large-Ring Cycloamylose

“…In our previous study, the binding constants ( K a ) of 4MC and CA were higher than PY and CT, but not higher than CHA and CFA [ 36 ]. This result was a different trend from previous studies that suggested that the extents of the enzyme reaction rate correlated with the affinity of the substrates participating in the complex formation [ 22 , 52 ]. Browning inhibitory properties via complex formation were typically due to PPO substrate sequestration or depletion [ 16 , 22 , 52 , 53 ].…”

“…This result was a different trend from previous studies that suggested that the extents of the enzyme reaction rate correlated with the affinity of the substrates participating in the complex formation [ 22 , 52 ]. Browning inhibitory properties via complex formation were typically due to PPO substrate sequestration or depletion [ 16 , 22 , 52 , 53 ]. However, some studies have argued for PPO inactivation by interaction with the hydrophobic amino acid side chain of PPO and the host molecules [ 20 , 54 ].…”

“…Several studies have been conducted using cyclodextrin (CD) as an anti-browning agent to control the oxidative and enzymatic degradation of PCs [ 15 , 16 , 17 , 18 , 19 , 20 ]. Native CD (α-, β-, and γ-CD) are small cyclic glucans composed of six, seven, or eight glucose units that possess hydrophobic inner cavities [ 21 ], delaying enzymatic browning by partially complexing the PPO substrate [ 22 , 23 ]. Among those three CDs, β-CD has been more widely studied and applied in food industry, because the application scope of α-CD is small due to its small molecular cavity size and the production cost of γ-CD is high [ 24 ].…”

Peach polyphenol oxidase inhibition by 𝛃-cyclodextrin and 4-hexylresorcinol is substrate dependent La inhibición de la polifenoloxidasa de durazno por 𝛃-ciclodextrina y 4-hexilresorcinol es dependiente del sustrato

“…Cyclodextrins (CD) are natural cyclic oligomers built up from 6 (a-CD), 7 (b-CD), or 8 (g-CD) glucopyranose units. It has been reported that b-CD and derivatives, in combination with phosphate salts and antioxidants, inhibited browning of apple juices (Billaud, Regaudie, Fayad, Richard Forget, & Nicolas, 1995;Gacche, Zore, & Ghole, 2003;Hicks et al, 1996) and have been found to inhibit PPO of different sources (Casado-Vela et al, 2006), including sodium dodecyl sulphate (SDS)-activated peach PPO (Laveda, Nu´n˜ez-Delicado, Garcı´a-Carmona, & Sa´nchez-Ferrer, 2000). Recently, cyclodextrin derivatives have been shown to effectively inhibit browning of apple and peach juices (Lo´pez-Nicola´s, Nu´n˜ez-Delicado, Pe´rez-Lo´pez, Sa´nchez-Ferrer, & Garcı´a-Carmona, 2007;.…”

“…Cyclodextrins posses a hydrophobic inner cavity, in which PPO polyphenolic substrates can be trapped, forming inclusion complexes which render the polyphenols unavailable to PPO oxidation. Therefore, cyclodextrins inhibit PPO activity by an indirect mechanism: reduction of initial substrate concentration (Billaud et al, 1995). However, additional mechanisms for b-CD inhibition of PPO have been described, including SDS complexation (Laveda et al, 2000); non-competitive inhibition (Gacche et al, 2003) and a mixed inhibitory pattern, in which b-CD is suggested to interact also with hydrophobic portions of apple PPO (Alvarez-Parrilla et al, 2007).…”