Distinct Impacts of UV-A Light Wavelengths on Nutraceutical and Mineral Contents in Green and Purple Basil Cultivated in a Controlled Environment

Abstract

Controlled environment agricultural (CEA) systems create technological opportunities for the higher nutritional value of vegetables and herbs. It was hypothesized that UV-A light, supplementing basal light emitting diode (LED) illumination in CEA, would enhance growth and nutritional value (nutraceutical compounds and mineral element contents) in purple and green basil in a UV-A wavelength-specific manner. Therefore, blue (452 nm) and red (662 nm) 1:10 basal LED lighting (250 μmol m−2 s−1, 16 h) was supplemented with 1 mW cm−2 of 343, 366, 386, or 402 nm UV-A LED light for green ‘Italiano classico’ and purple ‘Red rubin’ basil cultivation. Different wavelengths have specific impacts for two basil genotypes, and certain light wavelengths should be selected to boost growth or to alter the contents of specific nutraceutical compounds. UV-A/violet 402 nm light enhanced growth, chicoric acid, β carotene, lutein, and zeaxanthin contents in green basil, while 343 nm UV-A light increased fresh weight, ascorbic acid, and carotenoid content in purple basil. UV-A light of 386 nm has the most negligible impact on reducing mineral element (P, Ca, Fe, K, Mg, Mn, and Zn) contents in basil. Understanding the wavelength dependence of plant responses to UV-A is essential for optimizing quality preservation and improving basil cultivation in controlled environment systems.