Enhancement of nutritional, flavor, and phenolic properties of hydroponically grown basil (Ocimum basilicum) through modification of nutrient solution composition

• A nutrient solution management method for cultivating low-potassium basil has been developed. • In the long-term treatment, the differences among the groups became even more pronounced. • Under long-term treatment with the potassium-free nutrient solution (N1K0), biomass was enhanced. • In addition, N1K0 long-term treatment results in reduced K level, increased VOCs, rosmarinic acids content and antioxidant activity. Basil is a widely consumed vegetable valued for both its culinary and medicinal properties. However, its naturally high potassium content can be problematic for individuals with impaired kidney function and related diseases. To produce low‑potassium basil by modifying the nutrient solution composition, basil cultivation was conducted under the hydroponic system in closed plant factory. We evaluated four treatments (N1K1, N1K0, N2K2, and N2K0) for their effects on basil growth, volatile organic compound (VOC) profiles, and antioxidant capacity (via ABTS assay) and conducted one-way analysis of variance (ANOVA) followed by Duncan’s multiple range test and Student’s t-test (using N1K1 as the control) to assess significant differences. After 21 days, all long‑term treatments increased plant biomass and significantly raised eugenol and other VOC levels compared to the control. Notably, the N1K0 treatment significantly enhanced total phenolic and rosmarinic acid content, achieving the highest ABTS activity. This approach offers a novel strategy for producing low‑potassium basil, while also improving yield and functional quality.