Enzymatic changes in plum (Prunus salicina Lindl.) subjected to some chemical treatments and cold storage.

Abstract

The objective of the present work is to see the effect of different chemical treatments on pectin methylesterase (PME) activity and softening of the fruits. Purple plums (cv. Satluj) fruits were harvested at colour break stage and treated for 5-minutes in aqueous solutions of salicylic acid at 138, 276 and 414 ppm, Ascorbic acid at 10,000, 20,000 and 30,000 ppm, and Gibberelic acid at 20, 40 and 60 ppm. For control the fruits were dipped in distilled water. Treated fruits were stored at low temperature conditions for 40 days. Physico chemical characteristics and PME activity were determined at 10 day interval. The colour of the fruits improved with respect to a* and b* values progressively throughout the storage, whereas, fruit firmness decreased. Total sugars and PME activity increased before showing a declining trend. Pre-storage application of salicylic acid (414 ppm) significantly delayed colour development. Fruits treated with salicylic acid (414 ppm) retained highest firmness, total sugars and PME activity at the end of storage.

Influence of pre-harvest sprays of calcium nitrate on storability and quality attributes of plum fruits

“…The decrease in L* value with advancement of storage period was also recorded in plum fruit by Steffens et al (2013). Increasing trend of a* and b* values with increase in storage period is in accordance with the observations of Majeed and Jawandha (2016) in 'Satluj Purple' plum.…”

Preharvest treatments with salicylates enhance nutrient and antioxidant compounds in plum at harvest and after storage

“…The observed effect of salicylates on delaying changes on quality parameters related to plum postharvest ripening could be attributed to their effect on delaying and decreasing ethylene production, given the climacteric behaviour of this plum cultivar , , . Similarly, it has been recently reported that postharvest SA treatment maintained quality parameters during storage in other plum cultivars, such as ‘Santa Rosa’, and ‘Satluj’ throughout a reduction in ethylene production. However, the present results show that preharvest treatment with salicylates not only maintained quality attributes during storage but was also effective in increasing them at harvest time.…”

Enhancement of Antioxidant Systems and Storability of Two Plum Cultivars by Preharvest Treatments with Salicylates

“…Thus, a significant delay of the postharvest ripening process was obtained by salicylate treatments by delaying colour, firmness and RI changes. Similarly, it has been recently reported that postharvest SA treatment maintained quality parameters during storage in other plum cultivars, such as “Santa Rosa” [ 14 , 15 ] and “Satluj” [ 16 ]. Since plums are climacteric fruit [ 28 ], the effects of salicylate treatments on delaying postharvest ripening process and maintaining quality attributes could be mediated by a reduction of ethylene production.…”

“…Similar increases in these antioxidant enzymes have been observed in peach fruits after postharvest SA treatment [ 13 ], which hasten cleaning of the superoxide radical generated during fruit ripening and, in turn, could be responsible for the effect of SA treatment on delaying the fruit ripening process. Specifically, in plums, it has been recently reported that SA postharvest treatments reduced chilling injury, softening, and colour evolution, leading to maintenance of fruit quality along storage at 20 °C or low temperature in “Santa Rosa” [ 14 , 15 ], “Satluj” [ 16 ], and “Qingnai” [ 17 ] cultivars.…”