FARKLI TARIM YÖNTEMLERİ VE HASAT ZAMANININ DOMATESLERİN ANTİOKSİDAN BİLEŞİKLERİ VE ANTİOKSİDAN AKTİVİTESİ ÜZERİNE ETKİSİ

Abstract

Tomato (Solanum lycopersicum) is an important fruit in human nutrition due to its rich content of bioactive compounds with antioxidant properties, including lycopene, β-carotene, ascorbic acid, and phenolic compounds. The antioxidant activity of tomatoes may be influenced by several factors such as genotype, environmental conditions, harvest time, and cultivation practices. This study aimed to compare the antioxidant activities of tomatoes cultivated under organic (Afyon-Başmakçı), conventional (Denizli-Sarayköy), and soilless (Afyon-Sandıklı) agricultural production systems, with samples collected in June and August. The samples were freeze-dried and extracted with 80% ethanol, and their antioxidant activities were evaluated using the 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. Antioxidant activity was determined by calculating the half-maximal inhibitory concentration (IC₅₀) values of the extracts. The IC₅₀ values of the tomato samples ranged between 97.93 and 947.10 µg/mL. Among the samples harvested in June, the highest antioxidant activity was observed in the soilless-grown tomato (H.T.: 423.54 µg/mL), followed by conventional (H.K.: 486.15 µg/mL) and organic (H.O.: 670.18 µg/mL) samples. Among the samples harvested in August, the highest antioxidant activity was observed in the conventional sample (A.K.: 97.93 µg/mL), followed by organic (A.O.: 898.15 µg/mL) and soilless-grown (A.T.: 947.10 µg/mL) samples. When compared across harvest periods, antioxidant activity increased in the conventional sample from June to August, whereas it decreased markedly in both organic and soilless-grown samples. These findings demonstrated that antioxidant activity varied considerably not only by cultivation method but also by harvest time. In conclusion, the antioxidant activity of tomatoes appears to be influenced not only by cultivation method but also by factors such as harvest time, environmental conditions, and genotype. Therefore, the evaluation of different agricultural production systems should consider all factors affecting nutritional quality rather than cultivation method alone.