Essential Oil Disinfectant on Appearance and Composition of Organically Grown Tomatoes

The essential oils of clove bud, thyme, and cinnamon, emulsified with gum arabic, were previously found to effectively inhibit microbiological growth at concentrations of 0.2 to 0.5% EO and to disperse in water. Organically grown firm ripe ‘Mountain Magic’ tomatoes were harvested in Knoxville TN and Waynesville NC in 2015 and washed with chlorine (200 ppm), water, clove bud oil (CBO) (0.2 and 0.5%), thyme oil (0.2 and 0.5%) or citrox (0.5 and 0.75%, an organic bioflavonoid/fruit aid blend). Tomatoes were held at 15 °C for 14 days and subsampled at 0, 7, and 14 days for weight loss, appearance, and composition. Weight loss was 0.3 and 0.5% after 7 and 14 days for all treatments. After 14 days, tomatoes treated with CBO or chlorine were borderline marketable. Those treated with water had slight flaws and those treated with citrox or thyme oil were intermediate in appearance. Fruit composition changed over storage time, with pH and lycopene content increasing. Total lycopene (78-83 mg/100 g fwt) was highest at all storage days for TO (0.2%). In contrast, soluble solids content was highest for the chlorine treated tomatoes after 0 and 7 days (6.6%) and lowest at 14 days storage. Total phenolic content of tomatoes decreased over storage for most treatments and increased slightly in tomatoes treated with thyme oil (400 to 440 mg/kg fwt). Our results indicate that ‘Mountain Magic’ tomatoes treated with essential oils generally had slight changes compared to water or chlorine. Thyme oil may have slightly stimulated compositional changes, as indicated by increases in total lycopene and phenol contents.