Led lighting as a factor in modifying the amino acid profile of tomato varieties in closed agroecosystems

The aim of this study is to investigate the effect of LED lighting with various spectral characteristics on the amino acid composition of tomato fruits grown hydroponically in controlled conditions of closed agroecosystems. The subjects of the study were the domestic tomato varieties Natasha and Timosha, intended for intensive cultivation in a multi-tiered narrow-rack hydroponic system. It was established that glutamic acid and glutamine are the key amino acids that form the basis of the fruit's composition. The study demonstrated that the tomato's response to different lighting spectra is cultivar-specific. Analysis revealed that white light (Natasha variety) and white light with added red (Timosha variety) provided the greatest increase in the content of most amino acids. In particular, treatment with white light led to an increase in the content of essential amino acids in Natasha fruits by 12.1–32.6 % compared to sodium lighting (DNaT). In Timosha tomatoes, the most pronounced increase in amino acid levels (7.0–56.6 %) was observed under a white spectrum with the addition of red. Leucine and isoleucine (32.6 %), valine (26.1%), and methionine (24.4 %) predominated in Natasha tomatoes, while arginine (56.6 %), methionine (51.7 %), phenylalanine (30.1 %), and valine (25.0 %) predominated in Timosha tomatoes compared to the control (DNaT). Lighting had virtually no effect on the lysine content of Natasha tomatoes or the histidine content of Timosha tomatoes: the concentrations of these amino acids remained at the control level, regardless of the spectrum used. The control lighting (DNaT) had low levels for most amino acids, inferior to the other lighting options considered. Thus, optimal control of the lighting spectrum ensured targeted changes in the amino acid composition of tomato fruits, significantly increasing their nutritional value and functional significance in closed agroecosystems.