3.2. Weight loss of fruit coating
The percentages of weight loss in the tested limes were
measured daily for the fruits stored at 25 C in an incubator with
60e65% relative humidity (Fig. 4 and Fig. 5). Calcium alginate
coated limes showed more weight losses than the control samples
(Fig. 4). At the end of 10-day storage, the weight loss of the control
sample was about 15.6% whereas the weight losses of (i) calcium
alginate coated limes, (ii) calcium alginate & 0.5% commercial
lignin coated limes, (iii) calcium alginate & 1% commercial lignin
coated limes and (iv) calcium alginate & 1.5% commercial lignin
coated limes were about 26.1%, 25.2%, 30.5% and 27.0%, respectively.
In the present work, calcium alginate coating showed
conflicting results observed by Valero et al. (2013) who reported
the decrease in weight loss for plumcultivars coated with 1% (w/v)
alginate & 20% (w/v) glycerol or 3% (w/v) alginate & 20% (w/v)
glycerol after 35 days of storage at 2 C and 90% relative humidity.
They stated that the decrease in weight loss was due to the fact
that the coatings acted as an extra layer which also coated on the
stomata leading to a decrease in transpiration and in turn to a
reduction in weight loss. However, coating fruit too thickly with
film may result in an increase in weight loss because of too low
oxygen concentration, excessive carbon dioxide concentration,
and generation of heat and production of end-products from
anaerobic fermentation (Ali et al., 2010). Moreover, these different
results are probably due to different study conditions, especially
relative humidity. Alférez and Burns (2004) studied postharvest
peel pitting at non-chilling temperatures (20 C) in grapefruit by
changes from low to high relative humidity during storage. They
stated that weight loss of fruit stored at lowrelative humidity (30%
RH) was about two times greater than that of fruit stored at high
relative humidity (90% RH). Thus, differences in the ability to
reduce weight loss were attributed to the different water vapor