Food-Based Natural Mitigators of Enzymatic Browning on Fruits and Vegetables: Insights into Active Constituents, Modes of Action, and Challenges

Abstract

Enzymatic browning is a major cause of postharvest quality loss in fruits/vegetables. Heat and chemicals are conventionally employed to prevent enzymatic browning. However, the demand for fresh-like fruit/vegetable products processed without chemical additives has shifted the paradigm towards natural antibrowning agents. Consequently, essential oils, hydrosols, honey, and plant extracts have received considerable attention as natural antibrowning agents during the last 4�5�years owing to the ability of their active constituents (flavonoids, phenolic acids, antioxidative peptides, thiol compounds, and/or carboxylic acids) to affect oxidative enzymes by (i) complexing at various sites through hydrogen, van der Waals, ?-sigma/?-? stack, electrostatic, and hydrophobic interactions, (ii) chelating metals at their active sites, and (iii) making conditions unfavourable for their activity as well as due to their ability to behave as membrane integrity promotors, substrate synthesis suppressors, and oxygen quenchers depending on the source, concentration, target fruit/vegetable, and processing conditions. However, their application in fruit/vegetable processing is challenging. For instance, plant extracts display high variability and lower effectiveness than synthetic antibrowning agents, while essential oils and hydrosols exhibit strong odours, limited solubility, and volatility. This article reviews the most recent studies on essential oils, hydrosols, honey, and plant extracts to provide an overview of the modes of action of natural antibrowning agents and highlight challenges associated with their utilisation. � 2023, The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.