Polyphenol Oxidase Substrates Research Articles

Identification and stability evaluation of polyphenol oxidase substrates of pineapple fruit

Pineapple as an important tropical fruit in the world is prone to internal browning (IB) caused by the oxidation of phenolic substances. To address the occurrence of IB, endogenous polyphenol oxidase (PPO) substrates were extracted, separated, and purified from pineapple fruit, and then four compounds were obtained and identified as catechin, epicatechin, chlorogenic acid and pyrocatechol. The contents of these substrates increased, reached the maximum value in the middle storage period, decreased gradually, and then maintained a relatively stable level by the end of storage. Meanwhile, pineapple PPO substrates were unstable in structure and susceptible to be degraded under the condition of light, high temperature (>40 °C), alkalinity (pH > 9) or metal ion (Ca2+, Cu2+, Fe2+, Pb2+ and Zn2+). Additionally, the presences of O2 and H2O2 increased the enzymatic oxidation of the pineapple PPO substrates, whereas CO2, N2, Vc (Vitamin C), l-cysteine, Na2SO3 and Na2S2O5 inhibited this oxidation.

Purification, characterization and inactivation kinetics of polyphenol oxidase extracted from Cistanche deserticola.

PPO was purified from Cistanche deserticola, and its enzymatic characteristics were clarified. It was found that microwave treatment was an efficient way to inactivate PPO. Polyphenol oxidase (PPO) from Cistanche deserticola was obtained and purified through an acetone precipitation and anion exchange column, the enzymatic characteristics and inactivation kinetics of PPO were studied. The specific activity of PPO was 73135.15 ± 6625.7 U/mg after purification, the purification multiple was 48.91 ± 4.43 times, and the recovery was 30.96 ± 0.27%. The molecular weight of the PPO component is about 66kDa by SDS-PAGE analysis. The optimum substrate of PPO was catechol (Vmax = 0.048 U/mL, Km = 21.70mM) and the optimum temperature and pH were 30°C and 7, respectively. When the temperature is above 50°C, pH < 3 or pH > 10, the enzyme activity can be significantly inhibited. The first-order kinetic fitting shows that microwave inactivation has lesser k values, larger D values and shorter t1/2. It was found that microwave treatment is considered as an efficient and feasible way to inactive PPO by comparing the Z values and Ea values of the two thermal treatments.

Recent Advances of Polyphenol Oxidases in Plants

Polyphenol oxidase (PPO) is present in most higher plants, but also in animals and fungi. PPO in plants had been summarized several years ago. However, recent advances in studies of PPO in plants are lacking. This review concludes new researches on PPO distribution, structure, molecular weights, optimal temperature, pH, and substrates. And, the transformation of PPO from latent to active state was also discussed. This state shift is a vital reason for elevating PPO activity, but the activation mechanism in plants has not been elucidated. PPO has an important role in plant stress resistance and physiological metabolism. However, the enzymatic browning reaction induced by PPO is a major problem in the production, processing, and storage of fruits and vegetables. Meanwhile, we summarized various new methods that had been invented to decrease enzymatic browning by inhibiting PPO activity. In addition, our manuscript included information on several important biological functions and the transcriptional regulation of PPO in plants. Furthermore, we also prospect some future research areas of PPO and hope they will be useful for future research in plants.

Catechol detection based on a two-dimensional copper-based metal-organic framework with high polyphenol oxidase activity

In this work, a novel sensing strategy for catechol was successfully developed based on a two-dimensional copper-based metal-organic framework (2D Cu-MOF) with high polyphenol oxidase activity. The 2D Cu-MOF was prepared from dimethylimidazole and Cu 2+ by stirring in a mixture solvent of methanol and water. We firstly found that the 2D Cu-MOF exhibited high polyphenol oxidase (PPO) activity by catalyzing the typical PPO substrate to produce a red color. And the PPO activity of the 2D Cu-MOF was higher than those of the other two reported PPO-mimicking enzymes at the same mass concentration. Subsequently, based on the effective PPO activities of the 2D Cu-MOF, we established a simple and rapid colorimetric method for detecting catechol with a detection limit of 0.35 μg·mL −1 . This method was also used to detect catechol in city water with satisfying results.

Potential of quercetin in combination with antioxidants of different polarity incorporated in oil-in-water nanoemulsions to control enzymatic browning of apples

Quercetin in combination with other antioxidants from natural sources and different polarity, including quercetin-3-rhamnoside, ascorbic acid, and α-tocopherol, were incorporated into oil-in-water (O/W) nanoemulsions to evaluate their effects on the activity of polyphenol oxidase (PPO) and browning of Granny Smith apple fruits. Additionally, molecular modeling methods were used to determine the ability and possible mechanisms of action of quercetin and quercetin-3-rhamnoside to inhibit PPO and to reduce the o-quinones derived from (–)-epicatechin, chlorogenic acid, catechol and methylcatechol (PPO substrates). Nanoemulsions were prepared using a low-energy emulsification method. In all nanoemulsions, Dynamic Light Scattering (DLS) analysis showed a size distribution of droplets between 100 and 500 nm diameter, whereas microscopical observation by freeze-fracture transmission electron microscopy (FF-TEM) corroborated the presence of the droplets and their size. Also, occasional arrangements consisting of stacked layers, with vesicle-like structures between them, were seen. The nanoemulsion 1, that contained the four antioxidants was the one that showed the best effect on PPO, inhibiting it by 41%, and inhibiting the browning of the apple flesh between 81 and 74% in a period of 6 h. Calculations with molecular modeling methods suggest that quercetin may be a more effective reducing agent than ascorbic acid and quercetin-3-rhamnoside, and could also act as a non-competitive inhibitor of PPO. While quercetin-3-rhamnoside represents a selective and competitive inhibitor of PPO. The most important function of α-tocopherol in the nanoemulsions could be the regeneration of quercetin to prolong its antioxidant activity.

NMR structural elucidation of dehydrodimers resulting from oxidation of 5-O-caffeoylquinic acid in an apple juice model solution

During apple juice and cider-making processes, phenolic compounds undergo enzymatic oxidation. 5-O-caffeoylquinic acid (CQA) is one of the major hydroxycinnamic acid derivatives and it is the preferential substrate for polyphenol oxidase (PPO) in apple juices. Consequently, CQA dehydrodimers (MW 706 Da) are among the main products resulting from CQA oxidation.CQA dehydrodimers were previously synthesized in a biomimetic apple juice model solution. Following their purification and characterization using UV–Visible spectra and mass spectrometry, the structures of seven CQA dehydrodimers were elucidated using 1H and 13C one- and two-dimensional NMR spectroscopy. Six of them exhibited dihydrobenzofuran, benzodioxane, or dihydronaphtalene skeletons, which are caffeicin-like structures. Interestingly, a new dehydrodicaffeoyldiquinic acid molecule was also characterised for which two novel structures showing a symmetric dicatechol skeleton were also proposed.

Characterization of polyphenol oxidase from purple sweet potato (Ipomoea batatas L. Lam) and its affinity towards acylated anthocyanins and caffeoylquinic acid derivatives

Biochemical characterization of polyphenol oxidase (PPO) present in purple sweet potato (PSP) is a key step in developing efficient methodologies to control oxidative damage caused by this enzyme to the valuable components of PSP, such as caffeoylquinic acid derivatives and acylated anthocyanins. Thus, this work focused on the assessment of the effects of pH, temperature, and chemical agents on the PPO activity as well as characterization of the PPO substrate specificity towards major phenolic compounds found in PSP. The optimum conditions of enzyme activity were pH 7 and a temperature range of 20–30 °C at which phenolic substrates were oxidized with 72.5–99.8% yield. Zn2+ ions remarkably reduced PPO activity while Cu2+ ions improved enzyme performance. The highest substrate preference was shown for 3,4,5-tri-caffeoylquinic and 3,5-di-caffeoylquinic acid, followed by 5-caffeoylquinic and caffeic acid, 3,4- and 4,5-di-caffeoylquinic acids, peonidin-3-caffeoyl-p-hydroxybenzoyl-sophoroside-5-glucoside. The highest Km values were found for 4,5-feruloyl-caffeoylquinic acid and catechol.

Engineering Alfalfa to Produce 2-O-Caffeoyl-L-Malate (Phaselic Acid) for Preventing Post-harvest Protein Loss via Oxidation by Polyphenol Oxidase.

Many plants accumulate high levels of hydroxycinnamoyl esters and amides in their tissues, presumably to protect against biotic and abiotic stress. Red clover (Trifolium pretense) leaves accumulate high levels [5–15 mmol/kg fresh weight (FW)] of caffeic acid derivatives, including phaselic acid (2-O-caffeoyl-L-malate). Oxidation of caffeoyl-malate by an endogenous polyphenol oxidase (PPO) has been shown to help preserve forage protein after harvest and during storage as silage, which should improve N use efficiency in dairy and other ruminant production systems. The widely grown forage alfalfa lacks both PPO and PPO substrates and experiences substantial loss of protein following harvest. We previously identified a hydroxycinnamoyl-coenzyme A (CoA):malate hydroxycinnamoyl transferase (HMT, previously called HCT2) responsible for phaselic accumulation in red clover. With the goal of producing PPO-oxidizable compounds in alfalfa to help preserve forage protein, we expressed red clover HMT in alfalfa. Leaves of these alfalfa accumulated mainly p-coumaroyl- and feruloyl-malate (up to 1.26 and 0.25 mmol/kg FW, respectively). Leaves of HMT-expressing alfalfa supertransformed with an RNA interference (RNAi) construct to silence endogenous caffeoyl-CoA acid O-methyltransferase (CCOMT) accumulated high levels of caffeoyl-malate, as well as the p-coumaroyl and feruloyl esters (up to 2.16, 2.08, and 3.13 mmol/kg FW, respectively). Even higher levels of caffeoyl- and p-coumaroyl-malate were seen in stems (up to 8.37 and 3.15 mmol/kg FW, respectively). This level of caffeoyl-malate accumulation was sufficient to inhibit proteolysis in a PPO-dependent manner in in vitro experiments, indicating that the PPO system of post-harvest protein protection can be successfully adapted to alfalfa.

Interactions between polyphenol oxidation products and salivary proteins: Specific affinity of CQA dehydrodimers with cystatins and P-B peptide

Throughout the apple juice and cider making process, polyphenols undergo enzymatic oxidation which generates a great variety of polyphenol oxidation products. Since 5′-O-Caffeoylquinic acid (CQA) is one of the major phenolic compounds and the preferential substrate for polyphenoloxidase in apple juice, its oxidation leads to the formation of newly formed molecules by which dehydrodimers (MW 706 Da) are included. Interactions of salivary proteins (SP) with native polyphenols is a well-known phenomenon, but their interactions with polyphenol oxidation products has not been studied yet. In this work, we decided to decipher the interactions between CQA dehydrodimers and SP (gPRPs, aPRPs, statherins/P-B peptide, and cystatins) using HPLC-UV and fluorescence. These results showed that contrary to what was expected, CQA dehydrodimers presented a low interaction with PRPs, but revealed a specific interaction with statherins/P-B peptide and cystatins. This work settles for the first time the interactions between SP and polyphenol oxidation products.

Effect of lactic acid bacteria on the postharvest properties of fresh lotus root

The oxidation of phenolic compounds caused by polyphenol oxidase (PPO) often contributes to the browning and decaying of lotus root. However, methods are limited to solve this problem and to effectively extend the shelf life of fresh lotus. Thus, lactic acid bacteria (LAB) were used in this study as an alternative solution. Michaelies-Menten equations analysis indicated that gallic acid, chlorogenic acid and catechin of lotus were the most optimal substrates of PPO. So Lactobacillus plantarum (LH-B02), Lactobacillus acidophilus (LA-05) and Lactobacillus casei (LC-01) were cultivated at the presence of gradient concentrations of these phenols, presenting different dose-effect relationship. The decomposition of polyphenols by effective strains was detected by HPLC analysis, indicating that after interacted for 30 h, 84.17% of catechin was transformed by LH-B02. When LH-B02 suspension (1.44 × 1011 CFU L−1) were sprayed on the surface of the lotus root for 1, 3, 5, and 8 times, the color loss of treated lotus root was significantly reduced (p < 0.01), compared with the control during the storage of 15 d. Texture properties involving hardness, chewiness, springiness and cohesiveness of the lotus was significantly (p < 0.05) enhanced, especially for the samples sprayed five and eight times, suggesting that LAB could improve the postharvest properties of lotus root.

The nature of β-cyclodextrin inhibition of potato polyphenol oxidase-catalyzed reactions

There is general interest in strategies to control polyphenol oxidase (PPO)-initiated enzymatic browning because it is often associated with declining food quality. Cyclodextrins are cyclic glucan oligosaccharides that form inclusion complexes with a number of PPO substrates. This study focuses on the effect of β-cyclodextrins (βCyD) on PPO-catalyzed reactions. Potato enzyme extracts and semi-purified potato PPO served as enzyme sources. Substrates included phenolics endogenous to potatoes. Reaction time-courses were followed spectrophotometrically; rates were compared by analysis of variance. Extents of βCyD inhibition of PPO-catalyzed reactions are shown to be substrate specific and can be quantitatively accounted for based on degrees of βCyD substrate sequestration. There was no evidence for direct irreversible βCyD inactivation of potato PPO. An apparent “direct PPO inactivation” by βCyD is shown to result from a sequence of sequestration-dependent reactions that occur in commonly employed assay systems for the quantification of PPO in fruits and vegetables.

Study on the Effects of Extraction and Purification Conditions on the Activity of Peroxidase and Polyphenol Oxidase from Chestnut Kernel and on Their Substrates

Chestnut kernel is a woody grain with high nutritional value and utilized value, but it is susceptible to Browning. Previous studies have shown that phenol is the substrate of enzymes that lead to browning. In order to investigate the substrates that that leads to browning of peroxidase (POD) and polyphenol oxidase (PPO) of chestnut kernel. The extraction and purification methods and the main substrates of POD and PPO from chestnut kernel were investigated. First, the effects on enzyme activity of different kinds of buffer, temperature, time and pH value were studied; second, the salting out purification of different concentrations and the main substrates of POD and PPO from chestnut were studied. The results were shown that POD enzyme in chestnut could be obtained by extracting with sodium dihydrogen phosphate-dibasic sodium phosphate buffer (pH 6.8) at 4°C for 5 h. PPO enzyme in chestnut could be obtained by extracting with disodium hydrogen phosphate-citric acid buffer (pH 5.4) at 4°C for 5 h. The two enzymes could be purified best by 80% ammonium sulfate, and the activity of POD and PPO enzyme had been enhanced for 60% and 190% respectively. Gallic acid might be the main substrate of POD and PPO in browning of chestnut kernel.

Bananas decrease acetaminophen potency in in vitro assays.

Edible portions of bananas contain high levels of polyphenol oxidase, which catalyzes reactions in the melanin formation pathway. Tyrosine, a physiological substrate of polyphenol oxidase, has an analogous structure to acetaminophen. We investigated whether banana extract causes structural changes in acetaminophen and a decrease in its potency. Acetaminophen concentration in banana extract was measured under different conditions to characterize incompatibility. Reaction products in solution were identified using liquid chromatography/electrospray ionization/mass spectrometry (LC/ESI/MS). Acetaminophen potency decreased with time in the presence of banana extract. The reaction proceeded most efficiently in temperatures 30–37°C and neutral to weakly acidic conditions. Molecular ion peaks derived from the oxidized catechol moiety of acetaminophen were identified in LC/ESI/MS spectra. Our findings suggest that incorporation or simultaneous administration of acetaminophen medication and banana juice may result in decreased efficacy of the clinically important drug. This interaction is likely due to the oxidation of acetaminophen by polyphenol oxidase activity in banana pulp. Therefore, we investigated and characterized a novel interaction between bananas and acetaminophen. To establish a safe and effective antipyretic analgesic regimen using acetaminophen, future studies of this interaction are expected to be performed in humans.

Effects of hot‐water and steam blanching of sliced potato on polyphenol oxidase activity

SummaryThe worldwide potato production is considered the fourth‐most important food sector due to the increasing use of potatoes as raw materials for high‐convenience food. Enzymatic browning, due to polyphenol oxidase (PPO), is related to unacceptability by consumer. Among antibrowning agents, thermal treatments are viable alternatives. In this study, the efficacy of hot‐water and steam blanching at 80–90 °C of potato slices (1‐cm thick) was evaluated in terms of colour changes as well as PPO inactivation kinetics, substrate specificity and transition state parameters. In general, all treatments [1] bleached the slices, [2] inactivated PPO and [3] reduced its kinetic efficiency. Results from thermal inactivation kinetics promoted hot‐water blanching at 90 °C for approx. 2 min as the fastest treatment to obtain enzymatic‐stable potato slices. Moreover, steam blanching required more energy (53.93 ± 1.24 kJ mol−1) than hot‐water treatment (41.41 ± 4.51 kJ mol−1) to reach the transition state and then to unfold the PPO enzyme.

Variable polyphenol oxidase (PPO) activity indicates grain quality in bread wheat (Triticum aestivum L.)

Wheat (Triticum spp.) is one of the important cereals in the world. Discoloration of wheat grains and accumulation of by product due to polyphenol oxidase (PPO) activities is an important problem faced by food industries. In this study, seeds of 115 Indian bread wheat cultivars representing different six agroclimatic zones were screened for their PPO activities using different PPO substrates, like caffeic acid, catechol, tyrosine and L-DOPA. Among these substrates, L-DOPA was found as best substrate to detect PPO activity. Highest PPO activity with L-DOPA was found in wheat cultivar HS 207, while lowest was detected in HP 1633. Among different agroclimatic zones, seeds of 40% of the cultivars representing NWPZ showed low PPO activity (< 10 unit min−1 g−1) with an average value of 14.22 unit min−1 g−1 and 38% cultivars of NEPZ had low PPO activity with the mean of 13.56 unit min−1 g−1. Therefore, wheat cultivars form NWPZ and NEPZ can be used for producing wheat byproducts.

Moderate vacuum packing and low temperature effects on qualities of harvested mung bean (Vigna radiata L.) sprouts

Post-harvest browning, decay, lignification, and other adverse physiological effects limit the shelf-life of mung bean sprouts at ambient temperature. In this study, vacuum packing at pressures of 0, ↓0.02, ↓0.04, and ↓0.06 mPa at 20 °C, and the optimum pressure of ↓0.04 mPa at 4 °C for maintenance of sprouts, was investigated. Chlorogenic acid was identified as the main phenolic compound leading to the browning of mung bean sprouts, along with total flavonoids, total phenols, rutin, and o-phthalic acid. Among these, flavonoids were identified as being the main substrate for polyphenol oxidase (PPO) activity. Moderate vacuum packing combined with low temperature storage inhibited PPO, as well as peroxidase (POD) and superoxide dismutase activities, which was associated with a slower rate of browning. In addition, these storage conditions reduced the activity of phenylalanine ammonia lyase (PAL), thereby suppressing the synthesis of phenolic substrates used in the browning reaction. Moderate vacuum packing combined with low temperature storage also maintained the activities of the cell wall-degrading enzymes cellulase and xylanase, and suppressed POD and PAL activities. Together, these effects would be expected to lead to a decrease in cellulose, hemicellulose, and lignin levels, ultimately restricting sprout elongation and maintaining the firmness of the sprouts.

Detection of Potential Chloroplastic Substrates for Polyphenol Oxidase Suggests a Role in Undamaged Leaves.

Polyphenol oxidases (PPOs) have a recognized role during pathogen and arthropod attack. As an immediate consequence of such wounding, cellular compartmentation is destroyed allowing the chloroplastic PPO enzyme to interact with vacuolar substrates catalyzing the oxidation of monophenols and/or o-diphenols to o-diquinones. This ultimately results in a reduction in the nutritional value of wounded tissue through the formation of non-digestible secondary melanin pigments. However, the chloroplastic location of PPO enzyme could indicate a role for PPO in undamaged tissues. In this study, a wild-type red clover population exhibiting high leaf PPO activity had significantly higher yield than a low leaf PPO mutant population while leaf isoflavonoids and hydroxycinnammates (PPO substrates) accumulated at similar levels in these plants. These data suggest that the presence of leaf PPO activity affects plant vigor. Understanding how this advantage is conferred requires knowledge of the cellular mechanism, including intra-organellar substrates. Here we present evidence of candidate PPO substrates within chloroplasts of wild-type red clover, including the monophenolic acid, coumaroyl malate, and low levels of the diphenolic acid, phaselic acid (caffeoyl malate). Interestingly, chloroplastic phaselic acid concentration increased significantly under certain growth conditions. We discuss the implications of this in regard to a potential role for chloroplastic PPO in undamaged leaves.

Subcellular extraction and enzyme characterisation of polyphenol oxidase and peroxidase in Cinnamon myrtle

Polyphenol oxidase (PPO) and peroxidase (POD) from Backhousia myrtifolia leaf and floral tissues were characterised. PPO from both tissues showed maximum activity at pH 6.0 and 10.0 at 25 °C, whereas POD activity optima were at pH 5.0 and 9.0 at 25 °C for leaf tissues. The same pH optima for POD activity were evident at 20 °C for floral tissues. With regard to substrate specificity, B. myrtifolia PPOs were of both monophenolase (tyrosine) and diphenolase (l-DOPA) types. POD activity was highest when catechol was used as a substrate for oxidisation. K m ranged from 0.6 to 1.0 mM with l-DOPA as the substrate for PPO, and from 0.1 to 0.4 mM with H2O2 and constant catechol (10 mM) as substrates for POD. In both tissues types, glutathione was a non-competitive inhibitor to PPO at the lower concentrations of 0.1–1 mM, but was uncompetitive at the higher concentrations of 10.0 mM. Sodium azide at concentrations ranging from 0.005 to 0.5 mM was a competitive inhibitor to POD. Subcellular extraction methods showed that PPO and POD were localised in the membrane fraction. Cationic native PAGE performed for both enzymes was only able to detect PPO activity. Using Western blot analyses, low molecular weight PPO isozymes from leaf tissue were identified (<10 kDa). Five POD isozymes (20–80 kDa) were detected in both tissue types. These ‘isoform’ patterns were investigated by two-dimensional gel electrophoresis (2DGE). PPOs were mainly neutral (pI 6–7), while POD isoforms had acidic, neutral and alkaline forms.

The effects of PPO activity on the proteome of ingested red clover and implications for improving the nutrition of grazing cattle

Increasing the rumen-stable protein content of feed would lead to improved nitrogen utilisation in cattle, and less nitrogenous waste. Red clover (Trifolium pratense L.) is a high protein ruminant feed containing high polyphenol oxidase (PPO) activity. PPO mediated protein-quinone binding has been linked to protecting plant proteins from proteolysis. To explore the mechanism underlying the effect of PPO on protein protection in fresh forage feeds, proteomic components of feed down-boli produced from wild-type red clover and a low PPO mutant, at point of ingestion and after 4h in vitro incubation with rumen inoculum were analysed. Significant differences in proteomic profiles between wild-type and mutant red clover were determined after 4h incubation, with over 50% less spots in mutant than wild-type proteomes, indicating decreased proteolysis in the latter. Protein identifications revealed preferentially retained proteins localised within the chloroplast, suggesting that PPO mediated protection in the wild-type operates due to the proximity of target proteins to the enzyme and substrates, either diffusing into this compartment from the vacuole or are present in the chloroplast. This increased understanding of protein targets of PPO indicates that wider exploitation of the trait could contribute to increased protein use efficiency in grazing cattle. Biological significanceOne of the main challenges for sustainable livestock farming is improving capture of dietary nitrogen by ruminants. Typically up to 70% of ingested protein-N is excreted representing a loss of productivity potential and a serious environmental problem in terms of nitrogenous pollution of lands and water. Identification of key characteristics of rumen-protected protein will deliver target traits for selection in forage breeding programmes. The chloroplastic enzyme PPO catalyzes the oxidation of phenols to quinones, which react with protein. Little is currently known about the intracellular protein targets of the products of PPO activity or the mechanism underlying protein complexing, including whether there is any specificity to the reaction. Here we have determined significant differences in the proteomes of freshly ingested down boli corresponding to the presence or absence of active PPO. These results show that in the presence of PPO the forage protein is less amenable to proteolysis and provide the novel information that the protected proteins are putatively chloroplastically located. These data also contribute to a growing evidence base that a chloroplastic PPO substrate exists in red clover in addition to the currently known vacuolar substrates.

Use of Modified Phenolic Thyme Extracts (Thymus vulgaris) with Reduced Polyphenol Oxidase Substrates as Anthocyanin Color and Stability Enhancing Agents.

Residual enzymatic activity in certain foods, particularly of polyphenoloxidase (PPO), is responsible for the majority of anthocyanin degradation in food systems, causing also parallel losses of other relevant nutrients. The present work explored the feasibility of modifying phenolic profiles of thyme extracts, by use of chromatographic resins, to obtain phenolic extracts capable of enhancing anthocyanin colour and stability in the presence of PPO activity. Results indicated that pretreatment of thyme extracts with strong-anion exchange resins (SAE) enhanced their copigmentation abilities with strawberry juice anthocyanins. Phenolic chromatographic profiles, by HPLC-PDA, also demonstrated that thyme extracts subjected to SAE treatments had significantly lower concentrations of certain phenolic compounds, but extracts retained their colour enhancing and anthocyanin stabilization capacities though copigmentation. Additional testing also indicated that SAE modified extract had a lower ability (73% decrease) to serve as PPO substrate, when compared to the unmodified extract. Phenolic profile modification process, reported herein, could be potentially used to manufacture modified anthocyanin-copigmentation food and cosmetic additives for colour-stabilizing applications with lower secondary degradation reactions in matrixes that contain PPO activity.