life of several weeks or months to a perishable one that
has only a very short shelf life, even as short as l-3 d at
chill temperatures.
Minimally processed produce deteriorates because
of physiological ageing, biochemical changes and microbial
spoilage, which may result in degradation of the
colour, texture and flavour of the produce7J. During
peeling and grating operations, many cells are ruptured,
and intracellular products such as oxidizing enzymes are
liberated.
Physiological and biochemical changes
The most important enzyme with regard to minimally
processed fruit and vegetables is polyphenol oxidase,
which causes browning 5,7. Enzymatic browning requires
the presence of four different components: oxygen, an
oxidizing enzyme, copper and a suitable substrate. To
prevent browning, at least one of these components
must be removed from the system. Another important
enzyme is lipooxidase, which catalyzes peroxidation