Apple is one of the most valuable fruits with a global production
estimate of about 75.64 million tons per annum [1]. Being an
important part of a healthy human diet, it contributes substantial
energy, antioxidants, vitamins, minerals and dietary fiber. In addition
to fresh consumption, it is processed into a variety of products
such as juice, jam and jelly. There has been growing interest of consuming
apple juice owing to its specific pleasant taste and high
nutritional value. However, quality defects arising during the processing
and storage of apple juice, if not checked, lower its scope
and market value.
Discoloration of apple juice due to enzymatic browning is the
major problem that deteriorates its quality. Polyphenoloxidase
(PPO) and peroxidase (POD) are the major enzymes responsible
for browning, especially, the former oxidizes phenolic compounds
to o-quinones that further polymerize and ultimately produce
undesirable brown color and off-flavored product [2–5]. Since
quality is of utmost importance for the consumers, it is desirable
to inactivate these deteriorative enzymes during processing and
storage of apple juice.