Prediction model for decay index of strawberry fruit based on ethanol content

For the purpose of fast detection of fruit decay in strawberry fruit during postharvest distribution by gas sensor array, a prediction model for decay index based on ethanol content was developed in this study. Freshly harvested strawberries were stored at different temperatures (273, 278, 283, 288, 293 and 298 K). Changes in decay index and ethanol content of strawberry fruit were determined during storage. Firstly, a kinetic model of ethanol content with respect to storage time and temperature was developed based on the Arrhenius equation. Secondly, a kinetic model of decay index with respect to storage time and temperature was also developed based on the zero order equation. Finally, a prediction model for decay index based on ethanol content was further developed according to the linear relationship between decay index and ethanol content. The three models were then verified with the strawberry fruit stored at 275, 280, 285, 290, 295 and 300 K. The relative prediction errors were found to be 0.76%, 5.89%, 7.08% respectively, and the prediction accuracy was acceptable. There was no significant difference in prediction accuracy between the kinetic model of decay index and prediction model for decay index based on ethanol content. The results suggest that decay index of strawberry fruit can be accurately predicted at the storage temperature from 273 to 300 K by the prediction model for decay index based on ethanol content, which lays the foundation for the non-destructive real-time measurement of fruit quality using gas sensor array.