Enzymatic browning can be initiated by enzymatic oxidation of
phenols to colored quinines, which are then subjected to further
reactions, leading to pigment formation (Nicolas, Richard-Forget,
Goupy, Amiot, & Aubert, 1994). Browning is a major problem for
various fruit products due to lowering of quality, safety, and
nutritional value. Typically, apple juices are expected to show a
yellowish color, which represents freshness. However, apple juices
are highly susceptible to enzymatic browning since polyphenoloxidase
in apple is highly active (Nicolas et al., 1994). Therefore,
proper control of the browning reaction in apple juice has gained
attention in the food industry.