A physical twin model for simulation of kiwifruit core temperature during pre-cooling and cold storage

Determination of fruit core temperature is crucial for fruit post-harvest management. However, there is still a lack of precise and real-time intelligent monitoring techniques of fruit core temperature for pre-cooling process and long-term storage. This study aims to establish a physical twin model capable of simulating kiwifruit core temperature. Firstly, we investigated the relationship between pre-cooling efficiency and six fruit characteristics of two kiwifruit cultivars. The results showed that fruit weight and fruit volume were the two main factors affecting the pre-cooling efficiency (R-2 = 0.68 in average), and physiological factors such as firmness and soluble solid content had less important impacts. Secondly, we developed a physical twin model comprising special clay and special soil, which could precisely simulate the kiwifruit core temperature (R-2 = similar to 0.999). Finally, the model was successfully used for intelligent determination of kiwifruit core temperature in pre-cooling through real-time detection algorithm and wireless transmission. Taken together, the physical twin model for the determination of kiwifruit core temperature developed in this study is a useful tool for temperature monitoring during postharvest pre-cooling.