Enhancing the shelf life of injera: design of an evaporative cooler clay chamber derived from local clay in Bahir Dar, Ethiopia

Abstract

Injera is Ethiopian ethnic traditional staple food, made from teff and other crops. The country’s superfoods are highly regarded in many Western countries for their excellent nutritional properties (‘very low gluten’), and mineral composition. Injera provides sufficient conditions for fungi to grow and ruin injera by changing the texture and making it inedible. This study aimed to develop an evaporative cooler clay chamber (ECCC) used to extend the shelf life of injera by controlling temperature and relative humidity (RH). This system is an economical and efficient way to lower the temperature and increase RH. The results show the maximum daily ambient temperature reduced from 28.98 °C to 22.90 °C and increased the RH of the storage chamber from 28.78% to 80.94%, respectively. The temperature drops up to 6.08 °C, and the RH rises to 52.16% observed. Additionally, the effects of temperature, RH and potential of hydrogen were studied for identified rotten injera and designed for injera storage. ECCC can store freshly made injera for 9 days before any visible mould stains appear, significantly reducing weight loss with an average cooling efficiency of 79.31%. Therefore, this study might help to develop low-cost cold storage for injera preservation at farms end in Ethiopia.

Keywords

• ambient temperature
• cooling efficiency
• evaporative cooler
• injera
• pH
• relative humidity