Applications of Ultraviolet Light–Emitting Diode Technology in Horticultural Produce: a Systematic Review and Meta-analysis

Abstract

Essential factor influencing the growth of plants is quality and type of light, development, and accumulation of phytochemicals, especially those grown in controlled conditions. Light is essential source for photosynthesis in higher plants, whereas light signalling is important in plant morphogenesis. The development of LED technologies enables for the optimization of photosynthetic processes and the regulation of plant physiology through the manipulation of light parameters. The plant morphology and functioning are influenced by the LED light quality, duration, and intensity producing responses at biochemical, physiological, and anatomical levels. LEDs also improve the nutritional profile of fruits and vegetables by inducing resistance to abiotic and biotic stress, as well as their effect on bioactive compounds, physiological properties, and ripening process. This paper reviews the role of LEDs in pre-harvest and post-harvest storage of fresh produce, including the effects on physiological characteristics, secondary metabolites, nutritional properties, ripening process, resistance to biotic and abiotic stress, and post-harvest disease occurrence. This review also focuses on the role of LEDs and the impact of their various bandwidths on the preservation of horticultural produce pre-and post-harvest. LED treatment can enhance several phytochemicals such as phenolic compounds, carotenoids, and vitamins. It has a significant impact on antioxidant capacity and anthocyanin content. LED was seen to be an efficient lighting source for delaying or accelerating ripening of fruits, and as well as delaying senescence. Therefore, LED lighting is an promising technology for enhancing the shelf life of vegetables by increasing disease resistance.

UV-A for Tailoring the Nutritional Value and Sensory Properties of Leafy Vegetables

“…It was reported that supplemental UV-A light resulted in bigger biomass, leaf area, pigment, antioxidant, and aliphatic glucosinolate contents in Chinese kale [17][18][19]; higher shoot biomass, antioxidant phenolics and sugar alcohols in ice plants [20]; higher biomass [21], anthocyanin and ascorbic acid [21], as well as increased protein concentration, mineral nutrients [22] in lettuce. Though showing comparable general trends, studies report species, UV-A dosage, and UV-A wavelengthspecific impacts [23][24][25][26]. Differential experimental conditions and basic lighting properties aggravate the comparison of the results.…”

Interactive effects of changes in UV radiation and climate on terrestrial ecosystems, biogeochemical cycles, and feedbacks to the climate system

“…LEDs are more energy-efficient and environmentally friendly than most traditional light sources used in horticulture (e.g. high-pressure sodium vapour or metal halide lamps), and by utilising LEDs that emit both in the UV and PAR regions the control of the spectral composition, intensity and exposure period can be attuned to the light requirements of specific plants and crops [ 373 , 374 ]. However, at present, only UV-A LEDs have been widely adopted to stimulate the accumulation of desirable plant compounds [ 375 ].…”

Effect of ultraviolet light-emitting diode processing on fruit and vegetable-based liquid foods: A review

“…Ultraviolet light emitting diodes in the food industry are used in three main areas: food production, post-harvest storage, and food safety ( 17 , 18 ). Furthermore, this technology is one of the most promising alternatives for extending the shelf life of fruits and vegetables ( 56 ). Studies have been published showing the efficiency of LEDs in post-harvest applications, where LEDs were able to accelerate secondary metabolites during the ripening process ( 57 ), and both increase the volume and delay the loss of nutritional content in fruits and vegetables such as broccoli, citrus fruits, and strawberries ( 57 – 59 ).…”