Developing an Arduino-based control system for temperature-dependent gas modification in a fruit storage container

Abstract

Temperature is the most important factor affecting the quality and shelf life of fresh prduce. Varying temperature conditions are often observed during the supply chain of fresh produce. This poses a big challenge in designing modified atmosphere storage and transport containers. In this study, a system was developed to actively control CO2 and O2 concentrations inside a storage container under constant and changing temperatures. A mini air blower was used for gas exchange between the container and the external atmosphere. A thin and long tube prevented air from entering the container but facilitated air exchange when the blower was switched ON. The blower ON frequency (s h−1) was modelled as a function of storage temperature, taking into account the type and amount of fruit, blower properties, tube dimension, and the setpoint of O2 concentration. The model was then used in programming an Arduino microcontroller to control the blower in response to real-time measurement of storage temperature. The gas control system was then validated by the storage of sweet cherries. The system could control the CO2 concentration at the setpoint level (12.5%) for constant temperature of 6 °C and 17 °C and changing temperature from 17 °C to 9 °C. The blower ON frequency ranged from 32 s h−1 at 6 °C to 350 s h−1 at 17 °C. There was a good agreement between the measured and predicted values of gas concentration obtained from the simulation. The maximum RMSE value of predictions was 0.30 % at 17 °C storage temperature.