Enzymes in Quality and Processing of Tropical and Subtropical Fruits - Tropical and Subtropical Fruits: Postharvest Physiology, Processing and Packaging - page 44

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Control of cellulase in tropical
and subtropical fruits
In addition to control methods previously described for
other enzymes in this chapter, reducing oxygen concentra-
tions (2.5-5.5%) has been used as an effective measure to
diminish the accumulation of polygalacturonase and cellu-
lase proteins and the expression of their isozymes thereby
controlling their activities during ripening (Kanellis et al.,
1991). In bananas, salicylic acid treatment has been found to
delay the ripening of banana fruits ( Musa acuminata )which
was attributed to the decrease in the activities of major cell
wall-degrading enzymes including cellulase, polygalactur-
onase, and xylanase (Srivastava and Dwivedi, 2000).

CONCLUSION
Enzymes are biological catalysts that play an essential role
in living organisms but are also responsible for both desir-
able and undesirable effects in foods derived from plants
and animals. The forgoing discussion has highlighted some
of these effects and the importance of controlling the ac-
tivity of enzymes responsible for postharvest deterioration
and losses in fruits. Though various control methods have
been shown to be effective, they must be optimized as
much as possible to preserve the sensory, nutritional, and
functional qualities of the fruit. Even though the traditional
methods of controlling enzymes in fruit processing have
been effective, most are accompanied by deteriorative re-
actions impacting negatively on the freshness and quality
of fruits. However, recent advances in processing types,
conditions, and strategies have been effective in control-
ling the deleterious postharvest effects from some enzymes,
while retaining optimal taste, color, texture, nutrients, and
other useful quality attributes associated with tropical and
subtropical fruits.

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