Harnessing the metabolic modulatory and antioxidant power of 1-(3-Phenyl-Propyl) cyclopropane and melatonin in maintaining mango fruit quality and prolongation storage life

Abstract

Background: The aim of this study was to compare and investigate the effects of 1-(3-phenyl-propyl) cyclopropene (PPCP) and melatonin (MT) as anti-ethylene agents on postharvest senescence, quality, chilling tolerance, and antioxidant metabolism in the mango fruit cv. "Keitt". The study involved exposing the fruit to 20 μL L^{- 1} PPCP or 200 μM MT, in addition to a control group of untreated fruit, before storing them at 5 ± 1 °C for 28 d. The findings revealed that the treatments with PPCP and MT were effective in reducing chilling injury and preserving fruit quality when compared to the control group.

Results: The use of 20 μL L^{- 1} PPCP was an effective treatment in terms of mitigating chilling injury and preserving fruit quality for 28 d. This was attributed to the decrease in metabolic activity, specifically the respiration rate and the production of ethylene, which led to the maintenance of fruit firmness and bioactive compounds, energy metabolism, and antioxidant activity, such as ascorbic acid, total flavonoids, trolox equivalent antioxidant capacity, dehydroascorbate reductase, glutathione reductase activity, ATP, and ATPase activity. The study also found that the MT treatment at 200 μM was effective in reducing chilling injury and weight loss and improving membrane stability. Additionally, it led to a decrease in malondialdehyde content and electrolyte leakage, and the maintenance of fruit quality in terms of firmness, peel and pulp colour values for mango peel and pulp total carotenoid content, as well as phenylalanine ammonia lyase and tyrosine ammonia lyase activity. These findings indicate that PPCP and MT have the potential to be efficient treatments in maintaining mango quality and minimizing post-harvest losses.

Conclusion: The utilisation of treatments with 20 μL L^{- 1} of PPCP or 200 μM MT was found to effectively preserve the postharvest quality parameters, in terms of bioactive compounds, energy metabolism, and antioxidant activity, of mangoes cv. "Keitt" that were stored at 5 ± 1 °C for 28 d.

Keywords: Chilling injury; Electrolyte leakage; Energy metabolism; Keitt; Mangifera; Shelf life.

Fig. 1

An illustration of the chemical structures and characteristics of melatonin (MT) and 1-(3-phenyl-propyl) cyclopropane (PPCP)

Fig. 2

Effect of PPCP (1-(3-phenyl-propyl) cyclopropane) and melatonin (MT) postharvest treatments on the chilling injury index (a), respiration rate (b), ethylene production (c) and weight loss (d) of ‘Keitt’ mango fruit stored at 5 ± 1 °C for 28 d. Vertical bars indicate the standard error of the means with different letters indicating significant variance (p ≤ 0.05) between means, as determined by Duncan’s multiple range test

Fig. 3

Impact of PPCP (1-(3-phenyl-propyl) cyclopropane) and melatonin (MT) postharvest treatments on the firmness (a), and total carotenoid content (b) of ‘Keitt’ mango fruit stored at 5 ± 1 °C for 28 d. Vertical bars indicate the standard error of the means with different letters indicating significant differences (P ≤ 0.05) between means, as determined by Duncan’s multiple range test

Fig. 4

Influence of PPCP (1-(3-phenyl-propyl) cyclopropane) and melatonin (MT) postharvest treatments on the malondialdehyde (MDA) content (a), electrolyte leakage (b), ascorbic acid (c) and total flavonoid content (d) of ‘Keitt’ mango fruit stored at 5 ± 1 °C for 28 d. Vertical bars indicate the standard error of the means with different letters indicating significant variance (p ≤ 0.05) between means, as determined by Duncan’s multiple range test

Fig. 5

Influence of PPCP (1-(3-phenyl-propyl) cyclopropane) and melatonin (MT) postharvest treatments on the trolox equivalent antioxidant capacity (TEAC) of ‘Keitt’ mango fruit stored at 5 ± 1 °C for 28 d. Vertical bars indicate the standard error of the means with different letters indicating significant variance (p ≤ 0.05) between means, as determined by Duncan’s multiple range test

Fig. 6

Effect of PPCP (1-(3-phenyl-propyl) cyclopropane) and melatonin (MT) postharvest treatments on the phenylalanine ammonia lyase (PAL) activity (a), and tyrosine ammonia lyase (TAL) activity (b), dehydroascorbate reductase (DHAR) activity (c) and glutathione reductase (GR) activity (d) of ‘Keitt’ mango fruit stored at 5 ± 1 °C for 28 d. Vertical bars indicate the standard error of the means with different letters indicating significant variance (P ≤ 0.05) between means, as determined by Duncan’s multiple range test

Fig. 7

Impact of PPCP (1-(3-phenyl-propyl) cyclopropane) and melatonin (MT) postharvest treatments on the ATP (a), and ATPase activity (b) of ‘Keitt’ mango fruit stored at 5 ± 1 °C for 28 d. Vertical bars indicate the standard error of the means with different letters indicating significant variance (p ≤ 0.05) between means, as determined by Duncan’s multiple range test

Fig. 8

Correlation matrix among several quality attributes of “Keitt” mango fruit in response to PPCP (1-(3-phenyl-propyl) cyclopropane), and melatonin (MT) treatments stored at 5 ± 1 °C for 28 d. Asterisks (^* or ^**) denote statistically significant difference at P ≤ 0.05 or 0.01, respectively, in the Pearson correlation analysis, which was performed with three replicates, CII: chilling injury index, RES: respiration rate, ETH: ethylene production, WL: weight loss, FIRM: firmness, CAR: total carotenoid content, MDA: malondialdehyde content, EL: Electrolyte leakage, AsA: ascorbic acid content, DAR: dehydroascorbate reductase, GR: glutathione reductase activity, PAL: phenylalanine ammonia lyase, TAL: tyrosine ammonia lyase, TFC: total flavonoids content, TEAC: trolox equivalent antioxidant capacity

Fig. 9

Principal component (PCA) analysis (PC1: 68.26%, PC2: 21.93%) of the quality parameters of “Keitt” mango fruit over 28 d of storage period at 5 ± 1 °C. PPCP (1-(3-phenyl-propyl) cyclopropane), melatonin (MT), Cont: untreated fruit, and numbers (0, 7, 14, 21, and 28) refer to storage days at 5 ± 1 °C, CII: chilling injury index, RES: respiration rate, ETH: ethylene production, WL: weight loss, FIRM: firmness, CAR: total carotenoid content, MDA: malondialdehyde content, EL: Electrolyte leakage, AsA: ascorbic acid content, DAR: dehydroascorbate reductase, GR: glutathione reductase activity, PAL: phenylalanine ammonia lyase, TAL: tyrosine ammonia lyase, TFC: total flavonoids content, TEAC: trolox equivalent antioxidant capacity