Articles
INVESTIGATION OF THE EFFICIENCY OF THE TOTAL ANTIOXIDANTS ASSAYS IN SILICON-TREATED LEMON FRUIT (CITRUS LIMON)
Article number
1007_7
Pages
93 – 102
Language
English
Abstract
The effect of postharvest silicon dips on the concentration of total antioxidants, total phenolics, and malondialdehyde, as well as the susceptibility to chilling injury of lemon fruit rind was studied.
Fruit from two orchards were soaked into different silicon concentrations (0, 50, 150, and 250 mg/L K2SiO3) for 30 min and thereafter stored at -0.5 or 2°C for 28 days with weekly evaluation of chilling injury and total flavedo antioxidants.
Total antioxidants were determined using three assays, the ferric reducing antioxidant power (FRAP), the 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay.
Silicon concentration in the flavedo was determined using Scanning Electron Microscope (SEM). Significant differences in endogenous silicon as well as chilling susceptibility between fruits from the two sources were observed.
Fruit stored at -0.5°C was less chilling susceptible compared with fruit stored at 2°C. However, the total antioxidant capacity in the rind did not differ between the two storage temperatures.
Postharvest silicon application had no effect on total phenolics, but an increase in the total antioxidants concentration and reduced malondialdehyde formation, a sign of membrane disintegration, was observed.
High silicon concentrations were found to impair visual fruit quality.
Chilling injury was reduced by 50 mg/L K2SiO3 and total antioxidants and total phenolics were significantly reduced at 150 and 250 mg/L K2SiO3 as determined by the FRAP, ABTS and DPPH assays.
Fruit source impacted on total antioxidants, total phenolics and malondialdehyde.
Fruits with high total antioxidants, total phenolics and low malondialdehyde were also found to have high silicon concentration.
Therefore, silicon has the potential to reduce postharvest chilling injury; however, preharvest silicon application should be considered as high silicon concentration from postharvest drench application impairs visual quality although improving total antioxidants in the rind.
Fruit from two orchards were soaked into different silicon concentrations (0, 50, 150, and 250 mg/L K2SiO3) for 30 min and thereafter stored at -0.5 or 2°C for 28 days with weekly evaluation of chilling injury and total flavedo antioxidants.
Total antioxidants were determined using three assays, the ferric reducing antioxidant power (FRAP), the 1,1-diphenyl-2-picrylhydrazyl (DPPH), and the 2,2-azino-bis-3-ethylbenzothiazoline-6-sulphonic acid (ABTS) assay.
Silicon concentration in the flavedo was determined using Scanning Electron Microscope (SEM). Significant differences in endogenous silicon as well as chilling susceptibility between fruits from the two sources were observed.
Fruit stored at -0.5°C was less chilling susceptible compared with fruit stored at 2°C. However, the total antioxidant capacity in the rind did not differ between the two storage temperatures.
Postharvest silicon application had no effect on total phenolics, but an increase in the total antioxidants concentration and reduced malondialdehyde formation, a sign of membrane disintegration, was observed.
High silicon concentrations were found to impair visual fruit quality.
Chilling injury was reduced by 50 mg/L K2SiO3 and total antioxidants and total phenolics were significantly reduced at 150 and 250 mg/L K2SiO3 as determined by the FRAP, ABTS and DPPH assays.
Fruit source impacted on total antioxidants, total phenolics and malondialdehyde.
Fruits with high total antioxidants, total phenolics and low malondialdehyde were also found to have high silicon concentration.
Therefore, silicon has the potential to reduce postharvest chilling injury; however, preharvest silicon application should be considered as high silicon concentration from postharvest drench application impairs visual quality although improving total antioxidants in the rind.
Publication
Authors
A. Mditshwa, J.P. Bower, I. Bertling, N. Mathaba
Keywords
chilling injury, antioxidants, silicon, phenolics, cold storage
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