Hurdle Technologies Using Ultraviolet Irradiation as Preservation Strategies in Fruit Juices: Effects on Microbial, Physicochemical, and Sensorial Qualities

Non-thermal processes are employed to decontaminate juice products with less negative impact on biochemical, sensorial, and nutritional properties of the products compared with traditional thermal processing. Different non-thermal technologies have been investigated to improve the quality and/or avoid undesirable changes in fruit juices that include ultraviolet (UV) irradiation, pulsed electric field (PEF), ultrasonication, ozonation, high-pressure processing, and membrane filtration. In this review, which focuses on current studies, largely from a decade ago, the combined impacts of UV irradiation and other non-thermal technologies (hurdle concept) on fresh fruit juices are addressed. The extensively researched products regarding the application of UV light processing to improve safety, maintain overall quality, and prolong shelf life were apple and orange juices. Based on the studies reviewed, the hurdle techniques (e.g., UV + PEF, UV + mild heat at 50 °C, UV-C + coupled microwave, UV + ultrasonication) reduced (> 5 log) spoilage/pathogenic microbes, viruses, and inactivated enzymes, while maintaining the fresh-like nutritional and sensorial quality of juices. However, achieving the right balance and synergy in hurdle technologies can be a challenge which should be more addressed in the future studies. Human trials also indicated that UV-irradiated juice had no cytotoxic effects on normal intestinal cells, but it stopped human colon cancer cells from growing. Treating fruit juices with UV in combination with other non-thermal hurdles could be an alternative to traditional thermal processing technologies in the food industry. However, commercialization, scale-up, regulatory, safety, economic, and ethical concerns of these technologies should be taken into consideration.