Quality predictions for bruised apples based on dielectric properties

摘要

The quality of an apple is influenced by static pressures during transport and storage. In this study, apples were subjected to different static pressures using a universal testing machine, and then the quality and dielectric parameters of the apples were measured after different storage durations (22 +/- 1 degrees C, 35-40% relative humidity). The results showed that the firmness and vitamin C content decreased and the total soluble solid (TSS) content, titratable acidity (TA), and total soluble solid/titratable acidity (TSS/TA) exhibited a decreasing-increasing-decreasing trend as the storage time increased. A principal component analysis (PCA) showed that two principle components could represent the dielectric parameters of the damaged fruit. At the characteristic frequency, which was selected using a gray correlation analysis, the principle components predicted the quality parameters and established a prediction model for the firmness, TSS content, and TSS/TA. The results are expected to provide a rapid evaluation method for damaged fruit using dielectric properties. Practical applications Mechanical damage to apples is often caused by external forces during harvesting, storage, and transport. During storage, injured fruits are infected easily by fungi and ultimately cause decay. In addition, rotten fruits and healthy fruits are stored together, which also leads to cross-infection and causes large economic losses. Therefore, a simple and practical technique to detect and evaluate the quality of damaged fruits is urgent. In this study, we conducted a study to measure the quality and dielectric parameters of apples that were subjected to different static pressures and found that two principle components could represent the dielectric parameters of the damaged fruit by PCA. At the characteristic frequency, which was selected using a gray correlation analysis, the principle components predicted the quality parameters and established a prediction model for the firmness, TSS content, and TSS/TA. The results are expected to provide a rapid evaluation method for damaged fruit using dielectric properties.