What are the primary roles of peroxidases in enzymatic browning of fresh-cut fruits and vegetables, browning promoters or ROS scavengers?
4 affiliations
- 1College of Biology and Agriculture, Shaoguan University
- 2School of Food Science, Shaoguan University
- 3Guangdong Provincial Key Laboratory of Utilization and Conservation of Food and Medicinal Resources in Northern Region, Shaoguan University
- 4Guangdong Provincial Engineering and Technology Research Center of Special Fruit and Vegetables in Northern Region, Shaoguan University
Abstract
Fresh-cut fruits and vegetables, which undergo processes such as washing, peeling, cutting or slicing, packaging, and subsequent cold storage, represent a dynamic and expanding segment of the fresh produce industry (1). Despite minimal processing, they retain their raw, fresh state, offering consumers a valuable combination of high nutritional value, convenience, and superior flavor (2). However, the physical disruption of tissue integrity during processing alters their physiological behavior and storage requirements, significantly shortening their shelf life compared to the intact produce (3). Consequently, maintaining and even enhancing the safety and quality of fresh-cut fruits and vegetables necessitates rigorous management of enzymatic activity, respiration, and microbial proliferation. Among these quality challenges, enzymatic browning, characterized by undesirable dark discoloration, remains a primary concern (4). This adverse change diminishes both the visual appeal and nutritional quality of fresh-cut produce (5), leading to substantial postharvest losses. Fresh-cut processing inevitably compromises tissue integrity, allowing for direct contact between phenolic compounds and oxidases, particularly phenol oxidases, which are normally separated into distinct subcellular organelles through the compartmentalization of various membranes (6). Upon wounding, the release of phenolic compounds and phenolases triggers immediate oxidation in the presence of atmospheric oxygen within plant cells. Oxidative enzymes, particularly polyphenol oxidase (PPO) and certain peroxidases, catalyze the oxidation of such phenolic compounds into highly reactive quinones, which then polymerize to form brown melanin-like polymers or other dark pigments (7).While it is well-established that phenolase-mediated reactions drive the browning process, research has historically prioritized the role of PPO (8-10). Given the multifunctional roles of peroxidase in plant systems, its specific contribution to enzymatic browning remains poorly understood, and its potential as a regulatory target has yet to be fully exploited. Therefore, this opinion aims to review the multifaceted roles of peroxidase in enzymatic browning, highlighting its significance as a potential target for controlling browning in fresh-cut produce. Additionally, we propose that peroxidases act as context-dependent modulators, with their effect determined by the specific isoenzyme, subcellular localization, or substrate specificity.Peroxidases are enzymes that decompose H2O2 while oxidizing a broad spectrum of phenolics and non-phenolic substrates like lignin and amine compounds. Peroxidases are ubiquitous, found in almost every living organism, from bacteria, fungi, animals, algae, and plants (11). Based on whether they contain a heme prosthetic group, peroxidases are classified as either heme or non-heme enzymes (12, 13). According to the RedoxiBase database, more than 80 % of characterized peroxidase genes encode heme-containing proteins (14). Non-heme peroxidases, such as glutathione peroxidases (GPX), thiol peroxidase, alkylhydroperoxidase, halo-peroxidase, NADH peroxidase, and non-heme catalases (Figure 1A), constitute only a minor fraction (15-17). Class II peroxidases are fungal extracellular enzymes that principally include lignin peroxidase, manganese peroxidase, and versatile peroxidase (Figure 1A). This class of peroxidases is central to the biodegradation and depolymerization of lignin in fungi (22). Manganese peroxidases, also secreted by these lignin-degrading fungi, catalyze the peroxide-dependent oxidation of Mn²⁺ to Mn³⁺ (23). Versatile peroxidases possess a hybrid molecular architecture that combines features of both lignin and manganese peroxidases. Unlike manganese peroxidases, which are specific for Mn²⁺, versatile peroxidases can oxidize phenolic and non-phenolic substrates, such as lignin, in the absence of manganese (24). Apparently, peroxidases in this class are not involved in browning reactions of fresh-cut produce.Class III peroxidases are abundant in the plant kingdom and include enzymes such as soybean peroxidase, horseradish peroxidase, peanut peroxidase, and others (Figure 1A). Studies have shown that peroxidases of this class perform a broad array of functions related to plant growth, development, and stress defense (25). These roles encompass the metabolism of ROS and reactive nitrogen species (26), modulation of plant growth and stress responses (27,28), lignification (29)(30)(31), wound healing (32), and more.Enzymatic browning of fresh-cut fruits and vegetables typically involves ROS metabolism, phenolic oxidation, and lignification, often occurring simultaneously or in combination (7, 9, 33). Given their broad catalytic range across the cell wall, vacuole, and apoplast, peroxidases may play important complementary roles in enzymatic browning, depending on species and storage conditions (34).ROS are highly oxidative molecules that can damage plant tissues, while cutting induces a ROS burst and accumulation in fresh fruits and vegetables (35). Elevated ROS levels can cause significant oxidative damage, particularly by compromising the integrity and functionality of cellular membranes. This breakdown facilitates direct interactions between phenolic substrates and oxidative enzymes, thereby catalyzing the enzymatic browning process (36). Consequently, managing ROS is crucial for reducing browning and maintaining the quality of fresh-cut fruits and vegetables (37).Peroxidases play a critical role in maintaining ROS balance and protecting plants against oxidative stress. Certain peroxidases, particularly non-heme peroxidases like GPX and Class I heme peroxidases such as APX and CAT, solely function in ROS metabolism, notably H₂O₂, thereby regulating browning in fresh-cut produce. GPX and APX reduce H₂O₂ by directly oxidizing reduced glutathione and ascorbic acid, respectively, using them as co-substrates within…
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BibTeX
@article{yuan2026what,
title = {{What are the primary roles of peroxidases in enzymatic browning of fresh-cut fruits and vegetables, browning promoters or ROS scavengers?}},
author = {Xiao Yuan and Zhaorui Zhu and Siju Wang and Xinjie Li and Jinsheng Cheng and Bin Wang},
journal = {Frontiers in Nutrition},
year = {2026},
month = jun,
doi = {10.3389/fnut.2026.1859645},
url = {https://doi.org/10.3389/fnut.2026.1859645},
note = {CC BY},
}
RIS
TY - JOUR
TI - What are the primary roles of peroxidases in enzymatic browning of fresh-cut fruits and vegetables, browning promoters or ROS scavengers?
AU - Xiao Yuan
AU - Zhaorui Zhu
AU - Siju Wang
AU - Xinjie Li
AU - Jinsheng Cheng
AU - Bin Wang
PY - 2026
DA - 2026/06/12
JO - Frontiers in Nutrition
DO - 10.3389/fnut.2026.1859645
UR - https://doi.org/10.3389/fnut.2026.1859645
AB - Fresh-cut fruits and vegetables, which undergo processes such as washing, peeling, cutting or slicing, packaging, and subsequent cold storage, represent a dynamic and expanding segment of the fresh produce industry (1). Despite minimal processing, they retain their raw, fresh state, offering consumers a valuable combination of high nutritional value, convenience, and superior flavor (2). However, the physical disruption of tissue integrity during processing alters their physiological behavior and storage requirements, significantly shortening their shelf life compared to the intact produce (3). Consequently, maintaining and even enhancing the safety and quality of fresh-cut fruits and vegetables necessitates rigorous management of enzymatic activity, respiration, and microbial proliferation. Among these quality challenges, enzymatic browning, characterized by undesirable dark discoloration, remains a primary concern (4). This adverse change diminishes both the visual appeal and nutritional quality of fresh-cut produce (5), leading to substantial postharvest losses. Fresh-cut processing inevitably compromises tissue integrity, allowing for direct contact between phenolic compounds and oxidases, particularly phenol oxidases, which are normally separated into distinct subcellular organelles through the compartmentalization of various membranes (6). Upon wounding, the release of phenolic compounds and phenolases triggers immediate oxidation in the presence of atmospheric oxygen within plant cells. Oxidative enzymes, particularly polyphenol oxidase (PPO) and certain peroxidases, catalyze the oxidation of such phenolic compounds into highly reactive quinones, which then polymerize to form brown melanin-like polymers or other dark pigments (7).While it is well-established that phenolase-mediated reactions drive the browning process, research has historically prioritized the role of PPO (8-10). Given the multifunctional roles of peroxidase in plant systems, its specific contribution to enzymatic browning remains poorly understood, and its potential as a regulatory target has yet to be fully exploited. Therefore, this opinion aims to review the multifaceted roles of peroxidase in enzymatic browning, highlighting its significance as a potential target for controlling browning in fresh-cut produce. Additionally, we propose that peroxidases act as context-dependent modulators, with their effect determined by the specific isoenzyme, subcellular localization, or substrate specificity.Peroxidases are enzymes that decompose H2O2 while oxidizing a broad spectrum of phenolics and non-phenolic substrates like lignin and amine compounds. Peroxidases are ubiquitous, found in almost every living organism, from bacteria, fungi, animals, algae, and plants (11). Based on whether they contain a heme prosthetic group, peroxidases are classified as either heme or non-heme enzymes (12, 13). According to the RedoxiBase database, more than 80 % of characterized peroxidase genes encode heme-containing proteins (14). Non-heme peroxidases, such as glutathione peroxidases (GPX), thiol peroxidase, alkylhydroperoxidase, halo-peroxidase, NADH peroxidase, and non-heme catalases (Figure 1A), constitute only a minor fraction (15-17). Class II peroxidases are fungal extracellular enzymes that principally include lignin peroxidase, manganese peroxidase, and versatile peroxidase (Figure 1A). This class of peroxidases is central to the biodegradation and depolymerization of lignin in fungi (22). Manganese peroxidases, also secreted by these lignin-degrading fungi, catalyze the peroxide-dependent oxidation of Mn²⁺ to Mn³⁺ (23). Versatile peroxidases possess a hybrid molecular architecture that combines features of both lignin and manganese peroxidases. Unlike manganese peroxidases, which are specific for Mn²⁺, versatile peroxidases can oxidize phenolic and non-phenolic substrates, such as lignin, in the absence of manganese (24). Apparently, peroxidases in this class are not involved in browning reactions of fresh-cut produce.Class III peroxidases are abundant in the plant kingdom and include enzymes such as soybean peroxidase, horseradish peroxidase, peanut peroxidase, and others (Figure 1A). Studies have shown that peroxidases of this class perform a broad array of functions related to plant growth, development, and stress defense (25). These roles encompass the metabolism of ROS and reactive nitrogen species (26), modulation of plant growth and stress responses (27,28), lignification (29)(30)(31), wound healing (32), and more.Enzymatic browning of fresh-cut fruits and vegetables typically involves ROS metabolism, phenolic oxidation, and lignification, often occurring simultaneously or in combination (7, 9, 33). Given their broad catalytic range across the cell wall, vacuole, and apoplast, peroxidases may play important complementary roles in enzymatic browning, depending on species and storage conditions (34).ROS are highly oxidative molecules that can damage plant tissues, while cutting induces a ROS burst and accumulation in fresh fruits and vegetables (35). Elevated ROS levels can cause significant oxidative damage, particularly by compromising the integrity and functionality of cellular membranes. This breakdown facilitates direct interactions between phenolic substrates and oxidative enzymes, thereby catalyzing the enzymatic browning process (36). Consequently, managing ROS is crucial for reducing browning and maintaining the quality of fresh-cut fruits and vegetables (37).Peroxidases play a critical role in maintaining ROS balance and protecting plants against oxidative stress. Certain peroxidases, particularly non-heme peroxidases like GPX and Class I heme peroxidases such as APX and CAT, solely function in ROS metabolism, notably H₂O₂, thereby regulating browning in fresh-cut produce. GPX and APX reduce H₂O₂ by directly oxidizing reduced glutathione and ascorbic acid, respectively, using them as co-substrates within…
SN - 2296-861X
ER -