دانلود رایگان مقاله انگلیسی اثرات درمانی ملاتونین بر کیفیت پس از برداشت میوه توت فرنگی - الزویر 2018

ABSTRACT

The effects of exogenous melatonin on postharvest life and quality in strawberry fruit after harvest were evaluated. To explore the optimum concentration of melatonin treatment, strawberry fruit were treated with 0, 0.01, 0.1, 1 and 10 mmol L−1 melatonin for 5 min and then stored at 4 °C and 90% RH for 12 d. The results showed that application of melatonin at 0.1 or 1 mmol L−1 was notably effective in reducing decay and weight loss of fruit. Senescence of strawberry fruit was clearly delayed by the 0.1 or 1 mmol L−1 melatonin treatment, as disclosed by the color, firmness, the total soluble solids content and titratable acidity of the fruit. Melatonin treatment at 0.1 or 1 mmol L−1 significantly reduced the accumulation of hydrogen peroxide (H2O2) and malondialdehyde (MDA), but increased the total phenolics and flavonoid contents, resulting in the higher antioxidant capacity. Nevertheless, melatonin treatment had a negative impact on the ascorbic acid content. The optimum concentration of melatonin for extending the postharvest life and improving the quality of strawberry fruit was 0.1 or 1 mmol L−1 . Moreover, melatonin treatment at 0.1 mmol L−1 enhanced the expression of melatonin biosynthetic genes including FaTDC, FaT5H, FaSNAT, and FaASMT and consequently increased the content of endogenous melatonin. These findings suggested that melatonin treatment may be a useful technique to extend the postharvest life and improve quality in strawberry fruit.

4. Conclusions

It can be concluded from this study that 0.1 or 1 mmol L−1 postharvest melatonin treatment was most effective in delaying senescence of strawberry fruit by reducing decay incidence, severity of decay and weight loss, delaying the color development, maintaining fruit firmness and titratable acidity, as well as decreasing the TSS, H2O2 and MDA content. Furthermore, 0.1 or 1 mmol L−1 melatonin treatment promoted the accumulation of total phenolics and flavonoid, resulting in higher antioxidant capacity. Nevertheless, melatonin treatment had a negative impact on the ascorbic acid content. Moreover, 0.1 mmol L−1 melatonin treatment enhanced the expression of melatonin biosynthetic genes including FaTDC, FaT5H, FaSNAT, and FaASMT and consequently increased the content of endogenous melatonin. In summary, melatonin treatment at intermediate concentration had positive effects on the postharvest life and quality of fresh strawberry fruit.