remarkable decrease in the ascorbic acid content of uncoated samples
was recorded after the twelfth day (Table 2).
Meanwhile significant changes and decreasing in the ascorbic
acid content were observed in chitosan coated samples after
eighteen days of storage. No significant differences were observed
between coated and uncoated samples after the first week (Fig. 2a).
After 26 days, ascorbic acid content of chitosan coated samples
was recorded as 105.9
±
11.9 mg/100 g while ascorbic acid content
of uncoated samples was observed as 83.6
±
16.8 mg/100 g. These
results corroborate the significant impact of chitosan coating on
preservation of ascorbic acid in A. melanandra fruits during storage.
Decrease in total polyphenol content of uncoated samples
was observed during the first twelve days, while a remarkable
reduction was observed from 12 to 26th day (Table 2). Total
polyphenol content of chitosan coated samples demonstrated a
very low decrease during the first 14 days, while this decline
was increased between 14 and 26 days. Chitosan coated berries
contained 102.9
±
9.04 mg/100 g of total polyphenols on average
meanwhile uncoated berries were distinguished by significantly
lower amount of total phenolics (60.6
±
4.62 mg/100 g) at the end
of storage. Coated samples were protected significantly better
even after the first four days of storage (Fig. 2b) and this process
continued similarly. It was observed that protected total polyphenol
content is related to antioxidant activity [19]. Consequently,
chitosan coated samples kept a higher antioxidant activity than
uncoated samples during prolonged storage process. Other authors
[18,20] ascertained that berries of Actinidia species, are excellent
sources of vitamin C. Mainly total polyphenols and vitamin C are
influencing factors of the total antioxidant capability in Actinidia
fruits. It was clearly reflected from the investigations that the
total vitamin C and polyphenols contents exhibited a great variation
amongst Actinidia species and high correlation with the total
antioxidant ability [18,20].
Soluble solids content of coated samples and uncoated samples
did not change significantly during the first four days and reached
11.53
±
0.03% and 12.85
±
0.02% after 26 days respectively (Fig. 2c).
As it was reported by Fisk et al. [21], total soluble solids were more
affected by choice of package and storage condition than by coating
treatment. Soluble solids content of uncoated samples were
recorded higher than that of coated samples after fourteen days
of storage. It shows that decomposition of uncoated samples was
found to be faster than the coated ones.
For a consumer, the fruit appearance is the most obvious feature
which can strongly affect the buying decision in a negative or
positive way. Now there are many unconnected factors which can
influence the appearance, from fruit injuries during collection to
its drying. Sensory analysis of A. melanandra based on visual appeal
showed that chitosan coatings delayed fruit senescence associated
with dehydration because chitosan coating provided more attractive
appearance of fruit surface. As other authors described, the
sensory test revealed that both coated and uncoated hardy kiwifruit