UV-A light treatment for controlling enzymatic browning of fresh-cut fruits

• The effect of UV-A LED irradiation on fresh-cut apples and pears was studied.
• Anti-browning was found to be related to irradiance, exposure time and the fruit cultivar.
• The effect of UV-A LED treatment on PPO activity has been demonstrated by colorimetric and zymographic assays.
• The use of LED diodes meets the needs for energy saving and environmental impact.
• UV-A LED treatment has great potential in the processing of fresh-cut products.

Enzymatic browning is critical in the preservation of the quality and the shelf-life of fresh-cut fruits. Non-thermal technologies such as UV radiation are emerging for controlling polyphenol oxidase (PPO) activity, the main agent responsible for browning. After determining the best operational conditions of a UV LED illuminator (2.43 · 10− 3 Wm− 2 irradiance), the anti-browning effect of UV-A light (390 nm) treatment at 25 °C over increasing time periods up to 60 min was assessed on fresh-cut apples and pears. Color variation (ΔE) and its percent reduction (%RΔE) were measured using a colorimeter and the greatest effect was observed in apples which showed higher %RΔE values than pears (58% vs 25% after 60 min exposure, respectively). Anti-browning was found to be related to irradiance, exposure time and the fruit cultivar. Overall this study confirmed UV-A LED technology as an eco-friendly alternative to traditional approaches for reducing browning of minimally processed products.Industrial relevanceTreatment of fresh-cut products with UV-A LED is not only easy and inexpensive to produce but also presents few hazards for humans. Moreover, the use of LED light sources brings many advantages such as energy savings, device durability, low environmental impact, high luminous efficiency and little thermal effect. UV-A LED technology has great potential to meet the demands of the food industry in the processing of fresh-cut fruits and vegetables. In addition it could also be considered a pre-treatment of fruits and vegetables being processed for the production of snacks.