Performance of a fabricated solar-powered vapour compression cooler in maintaining post-harvest quality of French beans in Kenya

Abstract

The quality and shelf life of French beans can be affected within hours of harvesting if the produce is not cooled after harvest. Solar-powered cooling systems are suitable for use in rural areas that are not connected to the grid. This study aimed at developing a solar powered cooling system to improve the quality of French beans in smallholder farms in Kenya. Freshly harvested French beans were stored under conventional field shed conditions and a solar-powered prototype cooler, after which weight and temperature were measured at intervals of 2 h and later packed in modified, atmosphere packaging bags. The bags were stored for 7 days in a cold room. Accumulated gas levels of oxygen and CO2 in the packaging bags were measured at the end of the shelf life. Significant differences (P≤0.05) in weight loss between produce stored in the conventional shed and those in the solar cooler prototype were observed. The weight of French beans reduced by 5 and 2.8% after 7 h under a conventional field shed and a fabricated solar cooler respectively. The volume of CO2 and O2 released from produce stored in a conventional shed and those in a fabricated solar cooler prototype were significantly different (P≤0.05).   Key words: Conventional cooling method, French beans, temperature, solar cooler, weight loss.