Apple slices tend to soften quickly and any minimal process
technique needs to address this additional problem. The softening
has been attributed to acid hydrolysis and also enzymatic degradation
(Ponting, Jackson, & Watters, 1971). The de-polymerisation
enzymes, such as polygalacturonase, are induced, as a response
to enhanced respiratory output. The firmness was significantly
(p < 0.05) higher in the shellac-coated slices, followed by aloe gel
and composite coated ones after 30 days of storage (Table 2). The
uncoated slices showed faster softening causing limited shelf life
of the samples. Aloe gel coating has also been reported to restrict
softening in sweet cherries (Martinez-Romero et al., 2006). This
may be attributed to the lower rates of water loss caused by the
application of the surface coatings.
Desiccation of apple slices is an important aspect during the
minimal processing and storage of apple slices. When the pretreated
slices are subjected to low temperature storage with or
without surface coatings, moisture diffusion plays an important
role in the water loss of the slices. During storage, humidity within