The improvement of the shelf life of vegetables through pre- and postharvest treatments

English: The improvement of the shelf life of carrots and tomatoes through integrated pre- and postharvest treatments was investigated. Preharvest ComCat® treatment of carrot and tomato plants was combined with postharvest disinfecting using chlorinated or anolyte water, modified atmosphere packaging in Xtend® film, and different storage temperatures. The physiological, chemical, biochemical and microbiological quality of carrots and tomatoes were effectively improved by the combined effect of modified atmosphere packaging in Xtend® film and the optimum storage temperatures of carrots, at 1°C, and tomatoes, at 13°C. The shelf life of carrots and tomatoes was effectively improved, while the quality characteristics were maintained. Disinfecting vegetables with anolyte water gave better results than chlorinated water. Chlorinated water treatment decreased ascorbic acid content, and increased physiological weight loss and peroxidase activity. The surface tissue of carrots was etched by chlorine, which created penetration zones for microorganism, and disadvantaged the shelf life. Disinfecting with anolyte water, in combination with modified atmosphere packaging and optimum storage temperatures, supported quality characteristics, and therefore contributed to improving shelf life of carrots and tomatoes. Preharvest spraying of plants with ComCat®, improved the quality of carrots. At harvest a slightly higher ascorbic acid, total soluble solids, total available carbohydrates and sucrose content was noted. The sucrose to hexose ratio at harvest was also slightly higher, and the microbial populations were slightly lower. Preharvest ComCat® treated tomatoes had a lower pH, fructose and glucose content, and higher titratabie acidity and peroxidase activity at harvest, which resulted in lower populations of natural microorganisms. During storage at 13°C and room temperature, ComCat® treated tomatoes displayed better maintenance of total soluble solids and ascorbic acid, and lower peroxidase activity. These tomatoes also maintained better microbiological and marketable quality. The free sugar content remained lower in ComCat® treated tomatoes as well as carrots during storage. It seems as if the fruit part of a plant is more affected by the ComCat® treatment, e.g. tomato, than the root part, e.g. carrots. The interactive effect of preharvest ComCat® spraying, disinfecting with chlorinated or anolyte water, modified atmosphere packaging in Xtend® film and different storage temperatures was significant on several postharvest quality parameters of carrots and tomatoes. The postharvest quality of ComCat® treated carrots and tomatoes in the storage atmosphere, created by forced ventilation evaporative cooling, was also better than that of the controls.