Impact of staggered treatments of novel molecules and ethylene absorbents on postharvest fruit physiology and enzyme activity of 'Santa Rosa' plums

- Staggered treatment of plum fruit has been reported for the first time.
- Staggered treatment of 'Santa Rosa' plum after 7, 14 and 21 days interval was effective and enhanced postharvest life.
- The most effective treatment was SA @ 2.0 mM followed by NO @ 0.5 mM.
- The staggered I, II and III set maintained shelf life of plum up to 10, 6 and 4 days, respectively in supermarket storage conditions.
- This may assist in taking decisions regarding beneficial effects of postharvest treatments if not applied immediately after harvest.

The present investigation was conducted to study the effect of staggered removal of cold stored (2 °C) plums at 7, 14 and 21 days interval and their subsequent treatment with salicylic acid (SA), nitric oxide (NO) and ethylene absorbent (EA) sachets. The fruit were then stored at supermarket conditions (20 ± 1 °C and 90 ± 5% RH) with the objective to know whether delayed EA, SA and NO treatments still have significant beneficial effects on the plum fruit quality. The observations on different physiological and biochemical parameters were taken at 2 days interval. The results showed that staggered treatments enhanced postharvest life and maintained fruit quality. We observed that SA-treated plums showed the highest fruit firmness and lowest decay losses when plums were either removed on 7th, 14th or 21st days of cold storage. Furthermore, SA-treated fruit exhibited lowest rates of respiration and ethylene evolution; phenylalanine ammonia lyase and pectin methyl esterase activities; minimum malondialdehyde content and lowest electrolyte leakage in comparison to those treated either with NO or packed with EA sachets or control fruit. In conclusion, 'Santa Rosa' plum removed after 7th (staggered-I), 14th (staggered-II) and 21st day (staggered-III) from cold storage maintained a shelf life of 10, 6 and 4 days, respectively at subsequent supermarket storage conditions. The overall results submit that even if the plums are not treated immediately or within few days after harvest and placed as such in cold store, they can be still treated with SA, NO or in-package ethylene absorbent (EA) treatment for beneficial postharvest influences.