Nondestructive detection of mechanical damage to citrus fruit based on electrochemical impedance spectroscopy

Abstract

Citrus fruit that suffer mechanical damage experience a decline in quality and economic value. Electrochemical impedance spectroscopy (EIS) measurements have revealed a correlation between impedance (ǀZǀ_4Hz) and extracellular fluid resistance (Re) with mechanical damage. This correlation is attributed to the disruption of cellular structures by mechanical damage that results in increased free water content and shortened current pathways, consequently decreasing the impedance values. However, owing to individual differences in samples, the damage-sensitive parameters in data are nonlinear separable. To address this issue, a method based on the selection frequency with a support vector machine (SVM) is proposed. This model demonstrated high accuracy, achieving 100% accuracy for model of ǀZǀ and θ as variables. However, the generalizability of the established model requires further systematic research. These findings provide new solutions for the application of electrochemical impedance for fruit quality detection.