Effect of adsorbent and acidulants on enzymatic browning of sugarcane juice.

Enzymatic browning is a major factor affecting
the quality of sugarcane juice, mainly due to the activities
of polyphenol oxidase (PPO) and peroxidase (POD). Effect
of bentonite (0–1%, w/v) on the activities of these
enzymes, when employed alone and also in combination
with acidulants, was determined. Bentonite alone could
reduce the activities of PPO and POD enzymes to 160 and
24.2 u/mL, respectively. The PPO and POD activity was
completely inhibited below pH 4.1 when ascorbic acid was
used alone or in combination with bentonite. However,
PPO and POD activity was inhibited to 60 and 51 u/mL,
respectively, at pH 3.7 when citric acid was used individually
and to 112 and 15.36 u/mL, respectively, when
employed along with bentonite. In addition, color changes
at 4 and 10 �C were measured during the storage of sugarcane
juice.