Development and performance evaluation of a refrigerated storage structure for preserving fresh fruits and vegetables

A prototype refrigerated unit with a capacity of 30 to 60 kg depending on bulk density was designed and developed to preserve fresh fruits and vegetables. The performance of the device was evaluated in terms of cooling time, cooling efficiency, specific energy consumption, unit device cost, and quality of stored products. Guava and cauliflower were stored in the device at 5 ± 1 °C and 6 ± 1 °C, respectively at 95 ± 2% relative humidity (RH) to evaluate the storing performance of the device. The cooling time was 2.08 ± 0.05 h at 5 °C and the device showed little fluctuation in relative humidity under load conditions compared to empty conditions at set temperatures of 5 °C and 6 °C. Notably, the cooling efficiency of the device was 93 ± 2% with specific energy consumption of 0.0524 and 0.1104 kWh/kg day for preserving guava and cauliflower, respectively. The overall preservation cost was $0.116 and $0.242 per kg per month for guava and cauliflower, respectively. The results revealed that the shelf life of guava extended for 18 days in this refrigerated device with minimal quality degradation and a weight loss of 3.78%, compared with freshly harvested guava. On the contrary, the weight loss, firmness, pH, and whiteness index for cauliflower at 18 days were 7.17%, 7.17 kg/cm2, 6.59, and 64.19, respectively. Meanwhile, the fresh cauliflower exhibited a firmness of 9.85 kg/cm2, a pH of 5.74, and a whiteness index (L*) of 65.58. The results demonstrated that the freshness of stored fruits and vegetables was preserved, meeting physiological and chemical quality standards. Therefore, the inexpensive refrigeration system, effectively maintains necessary temperature and humidity levels, offering a profitable solution for minimizing post-harvest losses at the greengrocer level. Additionally, the scientific methodology outlined can be readily applied to develop commercial-scale refrigeration units for preserving high-moisture produce.