permeability of the polysaccharides used in the formulation of the
coating solution.
There was no significant difference of weight losses among (i)
limes coated with xanthan gum & commercial lignin, (ii) locust
bean gum & commercial lignin and (iii) control samples. These
weight losses showed similar results with work done by Chen and
Nussinovitch (2000). They proved that no significant difference in
weight loss ranging between 2.3 and 3.2% of the original fruit
weight for the non-coated fruits (Citrus reticulate) and coated fruits
with 4e6% wax and 0.5e1.5% xanthan gum during storage for 27
days at 4 C and 68% relative humidity. However, water loss was
slightly less in lime coated with xanthan gum & extracted lignin
(Fig. 5). Coated limes with 0.2% xanthan gum & 1.5% extracted lignin
from 40% (w/w) NaOH in 50% (v/v) ethanol showed less weight
losses (13.8%) amongst those considered.
Water loss was slightly reduced in lime coated with 0.4% locust
bean gum & 1.5% commercial lignin or 0.8% locust bean gum & 1.5%
commercial lignin when compared with the control samples. Locust
bean gum had been reported that it is polysaccharide polymer
which is highly viscous aqua solution in a wide range of pH and
temperature (Aydinli & Tutas, 2000). In the case of 0.8% locust bean
gum, 0.4% xanthan gum and 0.8% xanthan gum solution, there was
a limited exchange of water vapor. This effect can be explained by
the hydrophilic nature of gum, which absorbs water and removes it
through the ambient (Zambrano-Zaragoza et al., 2013).
3.3. Surface color changes of coated fruit
The color of fruit epidermis was converted into a set of color
coordinates (L*, a* and b* values). Color coordinates range from
L ¼ 0 (black) to L ¼ 100 (white), a* (greenness) to þa* (redness),
and b* (blueness) to þb* (yellowness). The lightness (L*) gradually
increased during storage in both coated and uncoated limes. The
color change (Table 3) in uncoated fruits was enhanced and they
changed from green to yellow within 10 days of storage. During
ripening, the green chlorophyll pigment is degraded and turns to
the yellow color. The yellowness (b*) gradually increased during
storage in both coated and uncoated limes.