Methyl Jasmonate Treatments Extended the Postharvest Quality of Organically Produced Fresh Blackberry ( <i>Rubus fructicosus</i> L.) Fruits Through Restricting the Polygalacturonase Activity and Improving the Bioactive Compounds

Blackberry fruits ( Rubus fructicosus L.) are categorised as functional foods due to their rich bioactive compounds and high nutraceutical properties with a low glycaemic index. However, fresh blackberries necessarily deteriorate after harvest because of their fragile fruit tissue, causing difficulties in shelf life. Therefore, this study was carried out to investigate the effects of postharvest methyl jasmonate (MeJa) immersion treatments (0, 0.1, 1.0 and 10 mM) on the physicochemical and bioactive quality of organically produced ‘Jumbo’ blackberries during 16 days storage at 1 ± 0.5°C with an 85% relative humidity. MeJa efficiently maintained the physicochemical and bioactive properties of organic blackberries during the storage. MeJa delayed the losses in fruit weight and visual quality by restricting the polygalacturonase activity. Antioxidant activity was extended by MeJa through maintaining the total phenols, anthocyanins and ascorbic acids. Improvements in bioactive phytochemicals in MeJa‐treated fruits significantly delayed the malondialdehyde (MDA) and hydrogen peroxide (H 2 O 2 ) increases. MeJa treatment at 1 mM MeJa could be recommended to apply prior to storage as an innovative and health‐friendly approach for extending physical, bioactive and visual quality of fresh blackberries due to its greatest effects on extending many quality properties.