Assessment of Post-harvest Loss of Head Cabbage (Brassica oleracea L.Var.Capitata) Along Its Supply Chain to Jimma Market and Evaluation of Cooling Performance of Three Model Cold Storage Rooms

Abstract

Even though head cabbage is a highly nutritious leafy vegetable, a significant proportion of postharvest loss hinders its availability and utility. Therefore this study aimed at identifying the causes and extents of postharvest losses of head cabbage along its postharvest chain and evaluation of the cooling performance of three cold storage rooms. The assessment of postharvest loss of head cabbage was carried out using FAO's 4-S methodology and data were collected from 120 farmers, 3 retailers, and 3consumers through a questionnaire, focus group discussion, key informant interview, observation, and load tracking methods then analyzed by SPSS version 16. The cooling performance of constructed cold storage rooms was evaluated by recording both outside and inside temperature and relative humidity by using testo184H1 data logger with loading and no loading of head cabbage for twelve days respectively. Physicochemical parameters of head cabbage stored in those cold storage rooms after packed in sack and plastic crate were evaluated using RCBD replicating the sample three times then analyzed by Minitab version 16. The survey results indicated that the loss of head cabbage caused due to poor pre-harvest, harvesting, and post-harvest handling practices, lack of knowledge, and socio-demographic factors of the respondents. The losses 15.4%, 18%, and 20.6% were recorded at farmers, retailers and consumers level respectively. A high loss of head cabbage was recorded at consumers' level due to poor storage and processing condition and might due to accumulative factors from production to consumption point. Therefore to reduce loss at each supply chain, proper pre-harvest and post-harvest handling practices should be applied. The experimental results depicted that the average minimum and maximum temperature difference and the average minimum and maximum relative humidity difference were calculated with ambient air were 4.7°C and 12.6°Cand 40.6% and 19.9% for medium cold room, 2.4°C and11.9°C and 33.27% and11.7%for big cold room and a little and 8.8°C and 20.8% and 6.9% for small cold room respectively during no load test. The average minimum and maximum temperature difference and the average minimum and maximum relative humidity difference were calculated with ambient air were 3.4°C and 11.6°Cand 38.7% and 24.5% for medium cold room, 2°C and10.9°C and 30.2% and 16.5% for big cold room and a little and 8°C and 15.1% and 4% for small cold room respectively during loading of head cabbage. These cold storage rooms maintained firmness, reduced weight loss, pH, ascorbic acid, total soluble solids, Titratable acidity, and prolonged storage-life compared to ambient temperature. Head cabbage packed in plastic crate and stored in the medium cold room has a good potential in maintaining the quality and long shelf life of 12 days. To minimize internal temperature from increase and minimize internal relative humidity from decrease, the rooms should be monitored properly.