Abstract:
Composite edible coating comprising xanthan gum (0.
3%) and olive oil (0.1%) enriched
with antioxidants (gallic acid 0.1%, ferulic acid 0
.1% and ascorbic acid 0.1%) enhanced
the postharvest storability and nutritional quality
of table grapes. The quality
characteristics of table grapes were monitored duri
ng storage at 10±2°C, (70–75% RH),
at regular intervals of 6 days until 24 days of sto
rage. Xanthan gum combined with olive
oil reduced the weight loss, decay occurrence, accu
mulation of total soluble solids and
total sugars by reducing the rate of respiration an
d metabolism in the coated fruit.
Moreover, incorporation of antioxidants in coating
enhanced the level of phenolics,
ascorbic acid and total antioxidant activity in gra
pes. The activities of cell wall modifying
enzymes such as Polygalacturonase (PG) and Pectate
Lyase (PL) were reduced in the
fruits of treated sets as compared to that of the c
ontrol set. These results suggest that the
composite coating delayed the ripening and softenin
g process in grapes and thereby
extended their shelf life up to 24 days, while the
control grapes were decayed on the 12
th
day.
Keywords:
Composite edible coating, Nutritional quality,
Phenolic compounds, Shelf life
,
Vitis vinifera
L.
