The Natural Disinfectant Role of Essential Oils in Improving Radical Scavenging Activity and Total Phenolic Compounds in Fresh Vegetables

The objective of this study was to evaluate the radical scavenging activity (RSA) and total polyphenolic content (TPC) in petiolate vegetables (baby spinach) and sessile vegetables (<i>Romaine lettuce</i>) disinfected with essential oils of thyme and peppermint compared with bleach solutions, a chemical disinfectant widely used in food preparation. The vegetables, obtained from local markets in Granada (Spain), were treated with varying concentrations of essential oils and bleach solutions. Antiradical activity was evaluated using the DPPH radical scavenging method, while total polyphenols were determined using the Folin-Ciocalteu reagent. The results showed that essential oils significantly reduced microbial load, with inverse correlations between radical scavenging activity and microbial load and total phenolic compounds. Bleach solutions, on the other hand, show a strong direct correlation, significantly reducing the microbial load as well as the antiradical activity and total phenolic content. However, this antimicrobial and antioxidant effect depends on the morphological characteristics of the vegetable (stemmed or sessile) and the chemical composition of the essential oil. These results suggest that essential oils may be effective natural alternatives for disinfecting vegetables, as they increase their antiradical activity and polyphenolic content, in contrast to sodium hypochlorite, which affects the functional properties of the product by reducing the RSA and TPC.