Vol. 12, Issue 4 (2023)

Author(s):
Prajakta Phadtare, Sumit Inamdar, Vinayak Jadhav and AN Yadav

Abstract:
Onion storage is widely practiced worldwide in accordance to their cultural and economic practice. In India, method of storage adopted mostly depends on the traditional knowledge and commonly practiced methods are bag, pucca room, tat storage, bamboo, chawl structure and the losses associated are quite higher. Sprouting, desiccation and microbial spoilage are often observed in storage and it compels to choose advanced techniques like modified ventilated structures, modified atmospheric (MA) and controlled atmospheric (CA) storage. The CA and MA storage reduces the application of chemicals for sprout inhibition by manipulating the gas composition to extend the storage period of the onions. The onion bulbs are generally stored from May to November for a period of four to six months. However, 50-90 per cent storage losses are recorded depending upon genotype and storage conditions. The total storage losses are comprised of physiological loss in weight (PLW) i.e. moisture loss and shrinkage (30-40%), rotting (20-30%) and sprouting (20-40%). The PLW can be minimized by harvesting at right time, proper curing of onion bulbs and subsequent storage at desired temperature and humidity conditions. Generally, the rotting losses are at peak in initial months of storage, particularly in June and July, when high temperature coupled with high humidity result the losses. However, proper grading and selection of quality bulbs and good ventilation conditions can reduce the rotting losses. Application of post-harvest fungicidal sprays can also reduce the rotting. But this is not a practice in India. Sprouting losses are usually recorded at the end of storage period or when exposed to high temperature of humid air. Noticeable sprouting losses are observed because of storage of poor-quality bulbs having less rest and dormant period and also having thick neck. Comparatively, more sprouting losses are recorded in dark red and white onion cultivars than the light red onion cultivars. Hence the present investigation on, “Effect of different thicknesses of cooling pad of evaporative cooling chamber on inside environment and shelf-life of perishable commodities” Was under taken at research and development field of Farm Structure department Dr. Budhajirao Mulik college of Agricultural engineering and Technology, Mandaki-Palvan, Tal. Chiplun, Dist. Ratnagiri. To find out best suitable thickness of rap trap bond for storage onions. The rap trap bond of thicknesses 75mm (T1), 100mm (T2), 125mm (T3) and one room temperature storage structure (T0) were constructed. Depending on quality parameters viz. color index, Softness index, Physiological loss of weight, Moisture Content, Total soluble solids and acidity, present investigation were indicated that Treatment T3 shows better results followed by treatment T2, treatment T1, and treatment T0. The shelf-life of onions in T3 treatment was up to 14 days followed by treatment T2 (12 to 13 days), treatment T1 (10 to 12 days) and treatment T0 (6 days). Thus shelf-life of onion was increased by eight days in treatment T3 as compared to treatment T0. Depending on inside temperature and relative humidity, treatment T3 was shows better results followed by treatments T2, treatment T1, and treatment T0. Minimum temperature and maximum relative humidity shown by T3 treatment was 17 ºc and 90.4% respectively. Hence treatment T3 is considered as best suited for storage onions with good temperature and relative humidity conditions.