Controlling Enzymatic Browning in Apples: Inhibiting Polyphenol Oxidases Activity

Abstract

Objective The browning phenomenon in fruits, particularly in apples, is a result of various enzymatic reactions, with polyphenol oxidases (PPOs) being the primary culprits. These enzymes catalyze the oxidation of phenolic compounds in the presence of oxygen, leading to the production of brown pigments, and compromising the quality, texture, and appearance of fruits. Aims This study aimed to investigate methods for mitigating enzymatic browning in apples by targeting the activity of PPO through the application of chemical treatments. Given the adverse impact of enzymatic browning on the sensory and nutritional qualities of apples, the research explored strategies involving chelating agents, antioxidants, agents of firmness, and acidifying agents. Methods Effective pre-treatment of apple samples was essential to overcome the natural cuticle barrier, thereby optimizing the efficacy of subsequent chemical interventions. The research revolved around the application of chelating agents, antioxidants, agents of firmness, and acidifying agents to suppress PPO activity. The systematic evaluation considered various concentrations of ascorbic acid, potassium metabisulfite (KMS), and sodium benzoate under diverse temperature and potential hydrogen (pH) conditions. Results The findings underscored the effectiveness of a variety of chemical treatments in inhibiting PPO activity, resulting in a noteworthy reduction in enzymatic browning in apples. Ascorbic acid exhibited substantial PPO inhibition at specific concentrations, while KMS and sodium benzoate demonstrated varying degrees of inhibition, ranging from moderate to prominent. Notably, the combination of KMS and sodium benzoate at an optimal concentration emerged as a highly effective approach, effectively preventing enzymatic browning across diverse conditions. Conclusion In conclusion, this research emphasizes the efficacy of chemical treatments, encompassing chelating agents, antioxidants, agents of firmness, and acidifying agents, in mitigating PPO activity and controlling enzymatic browning in apples. The synergistic effect of potassium metabisulfite and sodium benzoate displays significant promise, offering a viable solution to extend the shelf life of apples while preserving their sensory and nutritional attributes. These findings hold substantial significance in the realm of food preservation, with the potential to contribute to addressing global food scarcity challenges.