Assessment of phenolic content, pesticide residue and biological activities of organic lemon and cucumber in Lebanese market

Abstract

Purpose This study aims to evaluate the safety and quality of organic food product versus conventional ones in the Lebanese market. Design/methodology/approach Selected organic and conventional Lemon and cucumber were assessed for the presence of pesticides residues using LC-MS/MS and GC/MS/MS, also compared at the level of total polyphenols content, flavonoids, tannins and tested for their antiradical and antibacterial activities. Findings The findings indicate that organic lemons were contaminated by four types of pesticide residues (33.33%), while one pesticide residue (22.22%) was detected in conventional one, which were all below the European Union Maximum Residue Limits. For cucumber, six pesticide residues (66.66%) were detected in organic samples, while in conventional, eight pesticide residues (55.55%) were detected. However, absolutely four samples (44.44%) in each of conventional and organic cucumber samples surpass the maximum residue levels. Both lemon and cucumber, regardless of the farming systems, possess potent antioxidant activity with no significant difference, except for lemon, where total polyphenol was highly significant in conventional. Additionally, this study showed that lemon of conventional origin was slightly more effective in inhibiting the growth of gram-positive and gram-negative bacterial strains compared to organic samples, while both cucumber types did not exert any antibacterial effect. Originality/value This is the first paper to assess the polyphenols, pesticide residue and biological activities of organic lemon and cucumber in Lebanese market as well as comparing conventional to organic.