Postharvest calcium chloride treatments do not help to increase shelf-life of bananas

Abstract

Postharvest calcium chloride treatments do not help to increase shelf-life of bananas.Abstract -Introduction. Calcium chloride (CaCl 2 ) treatment has been shown to increase the shelf-life of fruits, mainly through making cell walls less accessible to pathogens and softening enzymes. Materials and methods. Bananas of four cultivars ['Ambon' (AAA), 'Embul' (AAB), 'Kolikuttu' (AAB) and 'Seenikehel' (ABB)] were dipped in or pressure infiltrated with 4% CaCl 2 . To determine the effect of exogenous ethylene on treated fruits, they were ripened with exogenous ethylene. Ca 2+ in cell wall fractions were monitored by atomic absorption spectrophotometry. Cup plate assays were performed to determine pectinase activity. Results and discussion. Pressure infiltration accelerated ripening and disease, and reduced firmness (P < 0.05). However, when exposed to ethylene, CaCl2 pressure-infiltrated bananas were insignificantly firmer than distilled water-infiltrated and ethylene-ripened bananas, showing a significant interaction (P < 0.05) between infiltration treatments and ethylene ripening. There was no consistent increase in covalently bound pectin of cell walls as seen in fruits that respond positively to CaCl 2 . Firmness reduction and ripening acceleration by Ca 2+ treatment cannot be explained if polygalacturonase (PG) (known to be inhibited by Ca 2+ ) was the dominant pectinase. Enzyme assays gave evidence of PG activity. When ammonium oxalate (known to bind Ca 2+ ) was eliminated from the test medium, pectinase activity increased with increasing pH (pH 5 to 9). The presence of a pectinase enzyme which exhibits activity in the presence of Ca 2+ is apparent. Conclusion. Ca 2+ does not appear to influence cell wall structure of bananas but appears to influence ripening physiology. Sri Lanka / Musa (fruits) / storage / calcium chloride / postharvest physiology / postharvest decay / polygalacturonase Le traitement au chlorure de calcium après récolte ne permet pas d'augmenter la durée de conservation des bananes.Résumé -Introduction. Le traitement au chlorure de calcium (CaCl2) permettrait d'augmenter la durée de conservation des fruits, principalement en rendant les parois cellulaires moins accessibles aux organismes pathogènes et aux enzymes de ramollissement. Matériel et méthodes. Les bananes de quatre cultivars ['Ambon' (AAA), 'Embul' (AAB), 'Kolikuttu' (AAB) et 'Seenikehel' (ABB)] ont été immergées dans une solution à 4 % de CaCl 2 ou soumises à une infiltration sous pression avec cette solution. L'effet de l'éthylène exogène sur les fruits traités a été testé lors de leur mûrissement. La présence de Ca 2+ dans des fragments de paroi cellulaire a été suivie par spectrophotométrie en absorption atomique. Des analyses ont permis de déterminer l'activité des pectinases. Résultats et discussion. Les infiltrations sous pression ont accéléré la maturation et le développement de maladies, et ont diminué la fermeté (P < 0,05). Cependant, exposées à l'éthylène, les bananes infiltrées sous pression avec du CaCl 2 ont été aussi f...

Effect of preharvest and postharvest application of calcium on banana green-life

“…In all treatments, the standard deviation had the same magnitude: between (7 and 17) d for Cavendish, and between (7 and 11) d Flhorban920 cvs. Our results are consistent with those of other authors on the shelf-life of banana dipped for 20 min in a CaCl 2 solution at 4% [10]. One hypothesis to explain this absence of effect is that the peel of banana is thick and relatively hydrophobic.…”

“…Furthermore, calcium was shown to modify pectins and hemicelluloses, which are known to influence the physical properties of fruits [6][7][8][9]. For banana, no effect of calcium on fruit shelflife has been shown [10].…”

Interactions of Colletotrichum musae and Lasiodiplodia theobromae and their biocontrol by Pantoea agglomerans and Flavobacterium sp. in expression of crown rot of “Embul” banana

“…Agrochemical use on bananas (both pre and postharvest) is negligible or absent in Sri Lanka. Because there seems to be a good market for exotic organic bananas (UNCTAD 2008), much attention has been paid to the control of postharvest diseases of local bananas by alternatives to agrochemicals (Adikaram et al 1995;Anthony et al 2004;Ethugala and Karunaratne 2002;Indrakeerthi and Adikaram 1994;Indrakeerthi 2006;Perera and Karunaratne 2002;Perera and Karunaratne 2001), for example the use of biocontrol (De Costa and Subasinghe 1998;De Costa and Erabadupitiya 2004;Gunasinghe et al 2004). Biocontrol of banana fruit pathogens has also been tried elsewhere (Chuang and Yang 1993;Mortuza and Ilag 1999;Lassois et al 2008).…”

Effect of pressure infiltration of calcium chloride on postharvest storage life of avocado (Persia americana Mill)

“…Then they were separated into four batches, each having three fruits per replicate. Calcium chloride pressure infiltration was performed by slightly modifying the method of Perera and Karunarathne (2002). Fruits were immersed in CaCl 2 solutions (2%, 4% and 6% concentrations) and pressure (250 mmHg) was applied for 10 minutes using an autoclave (T.S.I.…”