UVC\xa0light modulates vitamin C and phenolic biosynthesis in acerola fruit: role of increased mitochondria activity and ROS production

Marcela Cristina Rabelo,Maria Raquel Alcântara De Miranda,Ricardo Elesbao Alves,Vimal Nair,Luis Cisneros-Zevallos,Woo Young Bang,Daniel A Jacobo-Velázquez,Shareena Sreedharan

doi:10.1038/s41598-020-78948-1

Abstract

The effects of ultraviolet-C light (UVC) on vitamin C and phenolic compounds in acerola during postharvest storage were investigated in order to elucidate the mechanism inducing the antioxidant systems. The fruits, stored at 10 °C for 7 days after a hormetic UVC irradiation (two pulses of 0.3 J/cm2), showed significantly less degradation of vitamin C and phenolic compounds than the control without the UVC challenge. UVC activated the L-galactono-1,4-lactone dehydrogenase (GalDH), a key enzyme for vitamin C biosynthesis, and altered the composition of phenolic compounds, through phenolic biosynthesis, in acerola during postharvest storage. UVC also induced reactive oxygen species (ROS) productions at immediate (day 0) and late (day 7) times during postharvest storage through the mitochondrial electron transport chain and NADPH oxidase, respectively. Results suggest that UVC helps in the retention of vitamin C and phenolic content in acerola by altering ascorbic acid and phenolic metabolism through an increase in mitochondrial activity and a ROS-mediated mechanism. Data showed the beneficial effects of UVC on maintenance of nutraceutical quality in acerola during postharvest storage and supplied new insights into understanding the mechanism by which UVC irradiation enhance the antioxidant system in fruits.

Highlights

Consumption of tropical fruits has increased significantly in the past few years due to their attractive taste and nutritional value, which includes antioxidants such as vitamins and phenolic compounds
These results indicate that ultraviolet-C light (UVC) helps in the retention of vitamin C, especially reduced AsA, from degradation during postharvest storage of acerola
Phenolic compounds were significantly retained more in UVC treated acerola samples compared to controls after 7 days of storage (Fig. 3)

Summary

Introduction

Consumption of tropical fruits has increased significantly in the past few years due to their attractive taste and nutritional value, which includes antioxidants such as vitamins and phenolic compounds These fruits are highly perishable with limited shelf-life due to qualitative and quantitative deterioration during postharvest storage, which is mediated by a rapid maturation and senescence process[1]. Significant increases in flavonoids and total phenolic contents were found in mandarin fruit treated with 1.5 and 3.0 kJ/m2 UVC and stored for 3 days[16], similar results were reported for papaya[17] These data suggest that sub-lethal doses of UVC mediate the induction of antioxidant systems as secondary response to environmental stress, resulting in the extension of postharvest life and quality of a range of fruits. The mechanism by which UVC irradiation enhances the antioxidant level in fruits remains unknown

Methods

Results

Conclusion