Abstract:

In this study, either 1.25% chitosan (T1) or its combination with pomegranate rind extract (T2) was uniformly
sprayed on ‘Taishanhong’ pomegranate fruits, harvested and then stored at (4.0 ± 0.5) ℃ for 120 days. The weight loss,
total soluble solid, titratable acidity (TA), malondialdehyde (MDA) content, total phenol content, polyphenol oxidase
(PPO) activity, total soluble solid content, and decay incidence were investigated during storage. Results indicated that the
number of parenchyma cells close to the outer epidermic layer increased yet not significantly after both preharvest coating
treatments. Meanwhile, the freshness and moisture content of pomegranate peels were effectively maintained, and these
coating treatments could result in an increase in TSS content and a decline in TA content during the early stage of storage,
while not having a significant effect on the two parameters during the later stage of storage. Moreover, the contents of total
phenols and total flavonoids in pomegranate peels were maintained at higher levels and MDA formation caused by membrane
lipid oxidation was reduced during the early storage stage. In addition, T2 treatment could delay the occurrence of the peak of PPO
activity and increase the peak enzyme activity, while T1 treatment was not as effective in this regard. In conclusion, preharvest
coating could increase the shelf life and maintain the sensory quality of ‘Taishanhong’ pomegranate fruits.

Key words: pomegranate, chitosan, preharvest coating, storage