A Study on Low Cost Post Harvest Storage Techniques to Extend the Shelf Life of Citrus Fruits and Vegetables

An attempt was made to develop low cost porous evaporative cooling storage structures for extending the shelf life of citrus fruits and vegetables at the Sylhet Agricultural University campus, Bangladesh. Clay soil, bamboo and straw were used as a wall material. Sand, clay, zeolite, rice husk and charcoal etc. were used as a pad material. But the mixture of sand and clay was found as the most efficient pad materials for lowering temperature. Porous evaporative cooling storage structure (PECSS) was developed to reduce the problems of post-harvest losses at farmer level. It is eco-friendly and no energy requirements for storage of vegetables and fruits. PECSS improves the quality and productivity of vegetables and citrus fruits by reducing temperature, prolonging shelf life and reducing post-harvest losses respectively. The study revealed that shelf life of egg-plant (Solanum melongena) was 11 days in PECSS condition and it was 6 days in ambient condition. Therefore, weight loss was 4.07% for PECSS and 11.84% in room condition respectively. Storage life of Ladies finger (Abelmoschus esculentus) was 6 days more in PECSS condition than room condition. Weight loss was 6.62% in PECSS condition and 17.47% loss in ambient condition. In case of Malabar Spinach (Basella alba) it was 6 days for PECSS condition and 3 days for room condition and weight loss was found to be 9.48% and 16.17% respectively. The shelf life of stem amaranth (Amaranthus cruentus) was 5 days in PECSS condition and 2 days in ambient condition. Weight loss was found 7.05% at PECSS condition and 28.62% as in-room condition. By chemical analysis for fruits lemon (Citrus limon) and orange (Citrus sinensis) found that pH and TSS were increased both ambient and PECSS condition but in PECSS condition this rate was less than ambient condition. Vitamin C, percentage juice content, citric acid values all were decrease at both condition but in PECSS condition its rate was the less ambient condition. There is scope for intensive study to improve the firmness of the porous evaporative cooling storage structure (PECSS) to reduce the storage loss of vegetables and citrus fruits for different region and its suitability for large scale design.