Effect of pre- and post-harvest salicylic acid treatments on quality and antioxidant Properties of 'Red Delicious' apples during cold storage

Abstract

Salicylic acid is a natural phenolic compound known as a plant hormone having positive effect on storage life and quality of fruits. This study aimed to investigate the effects of pre- and post-harvest application of salicylic acid on antioxidant properties and quality of ‘Red Delicious’ apples during 193 days cold (0±0.5°C) storage. Both pre- and post-harvest salicylic acid treatments did not affect soluble solid content, titratable acidity and fruit firmness, with the exception of 1 mM at pre-harvest application for titratable acidity. Fruit juice pH was reduced in all fruits at the end of storage, while it was not quite uniform during storage. Although there was no significant difference between the concentrations of salicylic acid in terms of fruit weight loss, but the highest amount of weight loss was observed in post-harvest treatments. Salicylic acid application increased total phenolics and antioxidant activity at the earlier stages of storage showing the highest capacity with 2 mM followed by 1 and 4 mM salicylic acid concentrations, while 1 mM concentration belonged to the highest antioxidant capacity at the end of storage. Anthocyanin content showed a gradual increase during storage until day 60, then decreased right afterwards. The highest amounts of anthocyanin were obtained from the concentrations of 1 and 2 mM salicylic acid in pre-harvest treatments, while 4 mM treatment was not encouraging. Overall, salicylic acid treatments could increase apple storage life and quality for a short period of time only.