Zinc biofortification through seed nutri-priming using alternative zinc sources and concentration levels in pea and sunflower microgreens

Pradip Poudel; Francesco Di Gioia; Joshua D Lambert; Erin L Connolly

doi:10.3389/fpls.2023.1177844

Zinc biofortification through seed nutri-priming using alternative zinc sources and concentration levels in pea and sunflower microgreens

Front Plant Sci. 2023 Apr 17:14:1177844. doi: 10.3389/fpls.2023.1177844. eCollection 2023.

Authors

Pradip Poudel¹, Francesco Di Gioia¹, Joshua D Lambert², Erin L Connolly¹

Affiliations

¹ Department of Plant Science, The Pennsylvania State University, University Park, PA, United States.
² Department of Food Science, The Pennsylvania State University, University Park, PA, United States.

Abstract

Micronutrient deficiencies caused by malnutrition and hidden hunger are a growing concern worldwide, exacerbated by climate change, COVID-19, and conflicts. A potentially sustainable way to mitigate such challenges is the production of nutrient-dense crops through agronomic biofortification techniques. Among several potential target crops, microgreens are considered suitable for mineral biofortification because of their short growth cycle, high content of nutrients, and low level of anti-nutritional factors. A study was conducted to evaluate the potential of zinc (Zn) biofortification of pea and sunflower microgreens via seed nutri-priming, examining the effect of different Zn sources (Zn sulfate, Zn-EDTA, and Zn oxide nanoparticles) and concentrations (0, 25, 50, 100, and 200 ppm) on microgreen yield components; mineral content; phytochemical constituents such as total chlorophyll, carotenoids, flavonoids, anthocyanin, and total phenolic compounds; antioxidant activity; and antinutrient factors like phytic acid. Treatments were arranged in a completely randomized factorial block design with three replications. Seed soaked in a 200 ppm ZnSO₄ solution resulted in higher Zn accumulation in both peas (126.1%) and sunflower microgreens (229.8%). However, an antagonistic effect on the accumulation of other micronutrients (Fe, Mn, and Cu) was seen only in pea microgreens. Even at high concentrations, seed soaking in Zn-EDTA did not effectively accumulate Zn in both microgreens' species. ZnO increased the chlorophyll, total phenols, and antioxidant activities compared to Zn-EDTA. Seed soaking in ZnSO₄ and ZnO solutions at higher concentrations resulted in a lower phytic acid/Zn molar ratio, suggesting the higher bioaccessibility of the biofortified Zn in both pea and sunflower microgreens. These results suggest that seed nutrient priming is feasible for enriching pea and sunflower microgreens with Zn. The most effective Zn source was ZnSO₄, followed by ZnO. The optimal concentration of Zn fertilizer solution should be selected based on fertilizer source, target species, and desired Zn-enrichment level.

Keywords: agronomic biofortification; antinutrients; micronutrients; nutrient priming; phytic acid; phytochemical analysis; seed soaking.

Grants and funding

This research was funded by Open Philanthropy through the Food Resilience in the Face of Catastrophic Global Events grant. PP contribution has been supported by the Strategic Networks and Initiatives Program (SNIP) Soil, Plants, and Consumers funded by the Penn State College of Agricultural Sciences. FD contribution has been supported by the FD contribution has been supported by the USDA National Institute of Food and Agriculture and Hatch Appropriations under Project #PEN04723 and Accession #1020664