Potential of a solar powered walk-in cold room in extending shelf-life of fruits and vegetables: a case of mangoes and tomatoes

Abstract

Reducing Food Loss (FL) is one of the strategies for addressing food and nutrition insecurity. In developing nations like Uganda, FL focuses on Post-Harvest Loss (PHL), which accounts for food produced but not consumed. Fruits and vegetables are important components of a healthy diet due to their health and nutritional benefits. However, due to their highly perishable nature, they experience high levels of PHLs. In Sub-Saharan Africa, PHL in fruits and vegetables is estimated at 30-80%. The losses arise from limitations such as inadequate equipment and infrastructure from farm to markets. Experts recommend low temperature management as the most effective strategy for reducing PHL in perishable commodities. However, there is low adoption of cold storage in developing countries due to high costs of establishment and maintenance, and lack of access to affordable and reliable electricity. A prototype for a low-cost solar powered Walk-in Cold room (WIC) for storing perishable produce has been developed in Uganda. It overcomes the above-mentioned challenges associated with cold storage infrastructure. The purpose of this study was to assess the effectiveness of the WIC in extending shelf life of mangoes and tomatoes. Mangoes and tomatoes were stored in the solar powered WIC and under ambient conditions until they were unsalable. At 3-day intervals, changes in Physico-chemical attributes- Physiological Weight Loss, Firmness, Colour, Total Soluble Solids; nutritional attributes- Vitamins A and C, and microbial growth were assessed. Findings from the study indicate that the average temperature and relative humidity of the inner most chamber of the WIC were 7.3oC &74.6% and 7.2oC & 76.9% during storage of mangoes and tomatoes respectively. Compared to ambient conditions, the WIC preserved physical attributes of mangoes for longer; mangoes in the WIC became unsalable in 24 days compared to 12 days under ambient conditions, and physical damage was first observed on day 6 in the WIC compared to day 3 under ambient conditions. Tomatoes became unsalable in 18days under both storage conditions, but physical damage was first observed on day 9 in the WIC compared to day 3 under ambient conditions. The comparative advantage of the WIC was more evident in the first 6-9 days of storage. As it is, the WIC may not be effective for storing mangoes and tomatoes beyond 9 days.