Coupling Melatonin and Ultrasound Modulates ROS Production, Antioxidant System, and Biochemical Attributes Linked to...

Area of Science:

• Horticultural Science
• Postharvest Biology
• Plant Physiology

Background:

• Litchi (Litchi chinensis Sonn.) pericarp browning postharvest reduces market value.
• Browning is associated with oxidative stress from reactive oxygen species (ROS).

Purpose of the Study:

• To investigate the combined effects of ultrasound (US) and melatonin on litchi pericarp browning.
• To evaluate the impact on oxidative stress markers and overall fruit quality during ambient storage.

Main Methods:

• Litchi fruit were treated with ultrasound (37±3 kHz for 10 min) and melatonin (1 and 2 mM).
• Pericarp browning, ROS accumulation, polyphenol oxidase activity, anthocyanins, polyphenols, antioxidants, phenylalanine ammonia lyase (PAL) activity, weight, soluble solids, titratable acidity, and decay were assessed.

Main Results:

• Combined US and melatonin treatments showed the lowest pericarp browning scores (2.54 and 3.64).
• Treatments effectively mitigated oxidative stress, reducing ROS and polyphenol oxidase activity.
• Higher levels of anthocyanins, polyphenols, antioxidants, and PAL activity were maintained.
• Fruit quality parameters including weight, soluble solids, and titratable acidity were preserved, with reduced decay.

Conclusions:

• Combined ultrasound and melatonin treatments are effective in reducing litchi pericarp browning.
• This synergistic approach mitigates oxidative stress and enhances postharvest fruit quality.
• The treatment offers a promising strategy for extending the shelf life of litchi fruit.