Treatment of carrots with spent green tea extract reduces the soft rot of Pectobacterium spp.

Abstract

In the present study the antibacterial activity of spent green tea (SGT) was evaluated against Pectobacterium spp. causing soft rot incidence. Gas chromatography and mass spectroscopy (GC-MS) analysis reveal the presence of caffeine in the SGT extracts. Time kill assay revealed that SGT was able to kill Pectobacterium spp. at 18 h at 10 × MIC and at 24 h at 1 × MIC concentration. SGT led to the significant decrease in pectin lyase (PL), polygalcturonase (PG) and pectin methyl esterase activity in carrots challenge inoculated with Pectobacterium spp. SGT treated carrots recorded low degree of maceration, and relative electrolyte leakage (REL) values and also maintained high β carotene content, phenolic content and total antioxidant percentage. Based on the results of this study it could be concluded that SGT was able to offer protection to carrot against soft rot causing Pectobacterium spp. under post-harvest storage conditions.

Keywords:

• Antioxidative enzymes
• carrot
• pectic enzymes
• soft rot
• spent green tea

Abbreviations:

• GC-MS-Gas chromatography and mass spectroscopy
• MIC- minimum inhibitory
• PG- polygalcturonase (PG)
• PME- pectin methyl esterase
• PL- pectin lyase
• REL- relative electrolyte leakage
• SGT–spent green tea

Acknowledgements

Authors thank DST-SERB for the grant number SB/YS/LS- 79/2013, “Development of endophytic bacterial consortium from selected medicinal plants of Western Ghats of India,” for the support.