Enzymatic browning in apple products and its inhibition treatments: A comprehensive review

Apple (Malus domestica) is widely consumed by consumers from various regions. It contains a high number of phenolic compounds (majorly hydroxybenzoic acids, hydroxycinnamic acids, flavanols, flavonols, dihydrochalcones, and anthocyanins) and antioxidant activity, which are beneficial for human health. The trends on healthy and fresh food have driven the food industry to produce minimally processed apple, such as fresh-cut, puree, juice, and so on without degrading the quality of products. Enzymatic browning is one of the problems found in minimally processed apple as it causes the undesirable dark color as well as the degradation of phenolics and antioxidant activity, which then reduces the health benefits of apple. Proper inhibition is needed to maintain the quality of minimally processed apple with minimal changes in sensory properties. This review summarizes the inhibition of enzymatic browning of apple products based on recent studies using the conventional and nonconventional processing, as well as using synthetic and natural antibrowning agents. Nonconventional processing and the use of natural antibrowning agents can be used as promising treatments to prevent enzymatic browning in minimally processed apple products. Combination of 2-3 treatments can improve the effective inhibition of enzymatic browning. Further studies, such on as other potential natural antibrowning agents and their mechanisms of action, should be conducted.