Modulation of Antioxidant Compounds in Fruits of Citrus reticulata Blanco Using Postharvest LED Irradiation

Abstract

Phlegrean mandarin fruits are already known for health-promoting properties due to the high concentration of phytochemicals in peel, pulp, and seed. Biotic and abiotic factors, including light, may modulate their biosynthesis, metabolism, and accumulation. In this context, light-emitting diodes (LED) have recently been applied to control nutritional traits, ripening process, senescence, fruit shelf-life, and pathogenic microbial spoilage of fruits. This study investigated the effect of the seven-day exposure of Phlegrean mandarin fruits to two LED regimes, white (W) and red–blue (RB), to test the possibility that the storage under specific light wavelengths may be used as green preservation technology that enhances fruit phytochemical properties. To pursue this aim, the antioxidant activity and polyphenolic profile of the pulp and peel of mandarins under W and RB light regimes were evaluated and compared with Control fruits not exposed to LED treatment. Our results indicated that storage under W and RB treatments modulates the antioxidant content in pulp and peel differently. Compared to W, the RB regime increases the ascorbic acid, flavonoid, anthocyanin, and carotenoid concentrations, while the polyphenol profile analysis reveals that the number of important phytochemicals, i.e., quercetin rutinoside, chlorogenic acid, sinensetin, and rutin, are higher under W. The overall data demonstrated that postharvest LED irradiation is a valid tool for modifying fruit phytochemical properties, which also boosts specific bioactive compounds.

Light Quality Potentiates the Antioxidant Properties of Brassica rapa Microgreen Extracts against Oxidative Stress and DNA Damage in Human Cells

“…We can assume, as reported in [19], that compounds contributing to the antioxidant activity of RB extracts include some phenolics, namely flavones, flavanols, anthocyanidins, benzoic and cinnamic acids, which at specific concentrations-in our case, 1 µg/mL-may contrast and/or mitigate the DNA damage and the oxidative-induced genotoxicity. Identify-ing a method to boost such compounds in plant crude extract is worthy of attention because these molecules have powerful antioxidant, anti-inflammatory, and anti-cancer activity.…”

“…More specifically, as described by [19], RB light regimes increased the concentration of some flavones, flavanols, anthocyanidins, and benzoic and cinnamic acids in citrus fruits compared to W regime. The more specific qualitative analysis of the phenolic profile in fruits showed that RB light boosted some phenolic substances such as sinensetin, linarin, caffeic, ferulic, and vanillic acids, known for their anti-inflammatory, antimicrobial, cardioprotective, anticancer, and antidiabetic properties.…”

“…Specifically, phytochrome (red light) and cryptochrome (blue light), are involved in the accumulation of phytochemicals [39,40]. We assume that red and blue light may play a significant role in the activation of specific biosynthetic pathways, crucial for the synthesis of phenolics such as phenylalanine ammonia-lyase (PAL), chalcone synthase flavanone-3-hydroxylase and anthocyanidin synthase [19]. Consistent with other studies [43,44] our results also showed that phenolic substances strongly contribute to the antioxidant activity of brassica seedlings.…”

“…Recent studies proved that red and blue regions of the light spectrum are the most effective in influencing plant growth and phytochemical composition [18][19][20]. The use of red-blue light (RB) and white full-spectrum light (W) has distinct effects on plants.…”

Effects of the Cultivation Methods on the Sensory Quality and Phytochemical Profiles of Satsuma Mandarin (Citrus unshiu)

“…These flavor attributes and health-promoting properties are attributed to phytochemicals, including sugars, organic acids, flavonoids, limonoids, and terpenes [4]. The phytochemical profiles of citrus fruits depend on numerous factors, including the variety [5], growing region [6], postharvest treatment [7], storage conditions [8], and environmental growing conditions [2]. Factors such as the cultivation method, lighting conditions, fertilization, temperature, and soil moisture markedly affect the phytochemical profiles of citrus fruits [9][10][11].…”