Iodine biofortification of Swiss chard (Beta vulgaris ssp. vulgaris var. cicla) and its wild ancestor sea beet (Beta vulgaris ssp. maritima) grown hydroponically as baby leaves: effects on leaf production and quality.

BACKGROUND: About 35-45% of the global population is affected by iodine deficiency. Iodine intake can be increased through the consumption of biofortified vegetables. Given the increasing interest in wild edible species of new leafy vegetables due to their high nutritional content, this study aimed to evaluate the suitability of Swiss chard (Beta vulgaris ssp. vulgaris var. cicla) and its wild ancestor sea beet (Beta vulgaris ssp. maritima) to be fortified with iodine. Plants were cultivated hydroponically in a nutrient solution enriched with four different concentrations of iodine (0, 0.5, 1.0, and 1.5 mg L-1 ), and the production and quality of baby leaves were determined. RESULTS: Sea beet accumulated more iodine than Swiss chard. In both subspecies, increasing the iodine concentration in the nutrient solution improved leaf quality as a result of greater antioxidant capacity - the ferric reducing ability of plasma (FRAP) index increased by 17% and 28%, at 0.5 and 1.5 mg L-1 iodine, respectively - the content of flavonoids (+31 and + 26%, at 1 and 1.5 mg L-1 of iodine, respectively), and the lower content of nitrate (-38% at 1.5 mg L-1 of iodine) and oxalate (-36% at 0.5 mg L-1 of iodine). In sea beet, however, iodine levels in the nutrient solution higher than 0.5 mg L-1 reduced crop yield significantly. CONCLUSIONS: Both subspecies were found to be suitable for producing iodine-enriched baby leaves. The optimal iodine levels in the nutrient solution were 1.0 in Swiss chard and 0.5 mg L-1 in sea beet, as crop yield was not affected at these concentrations and leaves contained enough iodine to satisfy an adequate daily intake with a serving of 100 g. © 2023 Society of Chemical Industry.

Selenium Enrichment Enhances the Quality and Shelf Life of Basil Leaves.

The biofortification of leafy vegetables with selenium (Se) is a good way to increase human dietary Se intake. In addition, selenium delays plant senescence by enhancing the antioxidant capacity of plant tissues, decreasing postharvest losses. We investigated the effects of selenium addition on the production and quality of sweet basil (Ocimum basilicum) leaves of two harvesting phases, hereafter referred to as cuts, during the crop cycle. Plants were hydroponically grown and treated with 0 (control), 4, 8 and 12 mg Se L-1 as selenate. To evaluate the growth, nutritional value and quality of the basil leaves, selected qualitative parameters were determined at harvest and after five days of storage. Application of Se at varying rates (4, 8 and 12 mg L-1) was associated with an increased leaf selenium concentration in the first, but not the second cut. The application of Se significantly affected the antioxidant capacity as well as the total phenol and rosmarinic acid contents at harvest. The reduction in ethylene production observed in the plants at 4 mg Se L-1 after five days of storage suggests that this Se treatment could be used to prolong and enhance the shelf-life of basil. The daily consumption of 10 g of Se-enriched basil leaves, which, as an example, are contained in a single portion of Italian pesto sauce, would also satisfy the recommended selenium supplementation in humans.

Production of selenium-biofortified microgreens from selenium-enriched seeds of basil.

BACKGROUND: Microgreens (i.e. tender immature greens) are a popular alternative to sprouts (i.e. germinating seeds) because of their higher content of vitamins, carotenoids and phenols, as well as their lower content of nitrates. Their nutritional value can be improved by biofortification, which increases micronutrient levels during plant growth. Because selenium (Se) plays a significant role in antioxidant defense, biofortification with Se is a good way of improving the nutritional quality of sprouts and microgreens. The present study investigated the production of Se-fortified microgreens from Se-enriched seeds of sweet basil (Ocimum basilicum L.). These microgreens could be used as new beneficial dietary supplements. RESULTS: Basil plants were grown in a nutrient solution, containing 0 (control), 4 or 8 mg Se L-1 as sodium selenate, to full maturity. Seeds accumulated a high amount of Se and were then used to produce microgreens. The germination index was higher in the seeds from Se-treated plants and the microgreens were enriched in Se. The antioxidant capacity of Se-fortified microgreens was higher compared to the control. CONCLUSION: The production of microgreens from Se-enriched seeds could comprise a good system for obtaining microgreens with a high nutritional value. Basil plants treated with Se could be used to produce both Se-fortified leaves and microgreens. © 2019 Society of Chemical Industry.

Effect of selenium enrichment on metabolism of tomato (Solanum lycopersicum) fruit during postharvest ripening.

BACKGROUND: Selenium (Se) enrichment of plants seems effective in enhancing the health-related properties of produce and in delaying plant senescence and fruit ripening. The current study investigated the effects of Se on tomato fruit ripening. Tomato (Solanum lycopersicum L.) plants were grown in hydroponics with different Se-enriched nutrient solutions. Se, as sodium selenate, was added at a rate of 0 mg L-1 (control), 1, and 1.5 mg L-1 . RESULTS: Selenium was absorbed by roots and translocated to leaves and fruit. Enrichment with Se did not significantly affect the qualitative parameters of fruit at commercial harvest; instead it delayed ripening by affecting specific ripening-related processes (respiration, ethylene production, color evolution) during postharvest. In the current experiment 100 g of tomato hydroponically grown with a 1.5 mg Se L-1 enriched solution provided a total of 23.7 µg Se. Selenium recommended daily intake is 60 µg for women and 70 µg for men; thus the daily consumption of 100 g of enriched tomato would not lead to Se toxicity but would provide a good Se diet supplementation. CONCLUSIONS: The cultivation of tomato plants in a Se-enriched solution appeared effective in producing tomato fruit with improved performance during storage and postharvest shelf life, and also with greater potential health-promoting properties. © 2018 Society of Chemical Industry.

Selenium Enrichment of Horticultural Crops.

The ability of some crops to accumulate selenium (Se) is crucial for human nutrition and health. Selenium has been identified as a cofactor of the enzyme glutathione peroxidase, which is a catalyzer in the reduction of peroxides that can damage cells and tissues, and can act as an antioxidant. Plants are the first link in the food chain, which ends with humans. Increasing the Se quantity in plant products, including leafy and fruity vegetables, and fruit crops, without exceeding the toxic threshold, is thus a good way to increase animal and human Se intake, with positive effects on long-term health. In many Se-enriched plants, most Se is in its major organic form. Given that this form is more available to humans and more efficient in increasing the selenium content than inorganic forms, the consumption of Se-enriched plants appears to be beneficial. An antioxidant effect of Se has been detected in Se-enriched vegetables and fruit crops due to an improved antioxidative status and to a reduced biosynthesis of ethylene, which is the hormone with a primary role in plant senescence and fruit ripening. This thus highlights the possible positive effect of Se in preserving a longer shelf-life and longer-lasting quality.