Effect of fruit stalk on post-harvest physiology of tomatoes.

Abstract

This study investigated the effect of fruit stalk on the postharvest physiology and therefore shelf life of tomatoes in two common commercial tomato varieties grown in Uganda namely Top 22, 12 F1 and Ansal F1. Top 22,12 variety tomatoes were harvested from the Smart Green House Hydroponics Facility at Makerere University Agricultural Research Institute Kabanyolo (MUARIK), and Ansal F1 variety tomatoes were got from a vegetable farm near Semuto Township in Nakaseke district. Harvesting was done at the breaker stage of ripening considering the two treatments of with and without stalks, then stored for fifteen days using the experimental excogitation of Completely Randomized Design (CRD) inside cabinets in a laboratory environment at the School of Agricultural Sciences Plant Biotechnology laboratory set at Room temperature (25 ± 50C) and 70 ± 5 % Relative Humidity. The experimental materials were analyzed, and data collected at intervals of three days for fifteen days on percentage weight loss using an electronic balance, color development using Color Grab phone application, Total Soluble Solids (TSS) using hand refractometer, changes in pH using electronic pH meter, chlorophyll and carotenoid content using spectrophotometer. Data analysis was done using R-studio software (Version 4.3.1). Analysis of variance (ANOVA) was performed to test the difference between the two factors of variety and treatment, Fisher’s LSD at 5% significance level was to separate the means of the factors. The results showed that tomatoes harvested and stored with stalks were superior to those without. Stalked fruits had a lower (18%) percentage weight loss than stalked fruits (15%). Chlorophyll content was higher in stalked fruits (2.43 μg/ml) than in destalked fruits (2.39 μg/ml). Green peel color percentage was higher (52.1%) in stalked fruits than in destalked fruits (48.7%) while red peel color percentage was higher in destalked fruits (58.8%) than in stalked fruits (53.7%) implying that stalked fruits could last longer in storage due to delay in the physiological processes leading to above changes. Carotenoid content was not affected by treatments applied or variety as an individual factor but rather affected by the interaction between the two factors whereby destalked fruits of the two studied varieties had a higher mean carotenoid content (0.561 μg/ml) than in stalked fruits (0.433 μg/ml) on the third day of the experiment. This further revealed the effect of stalk removal in quickening ripening and eventual fruit spoilage. Total soluble solids were higher in destalked fruits (6.9%) than in stalked fruits (6.5%) implying that destalked fruits ripened and accumulated sugars faster than stalked fruits, however, faster ripening of destalked fruits leads to faster degradation and short shelf life. The pH of stalked tomato fruits was higher (4.6) than that of destalked fruits (4.4). The findings of this study suggest that harvesting tomatoes with stalks can help to improve their postharvest quality and shelf life because the stalk helps to maintain the moisture content of the fruit and may contain substances that help to delay ripening and senescence. These findings have implications for the tomato industry. By harvesting tomatoes with stalks, producers can help to ensure that their products reach consumers in good condition. This can lead to increased profits and satisfaction for producers and consumers alike.