“…According to the applied frequency, electrical methods are categorized into two kinds. The first method is based on an electrical parameter which is obtained from the single frequency, such as dielectric constant, dielectric loss coefficient, resistance, reactance, and impedance (Berbert et al., 2019; Nigmatullin, Arbuzov, Nelson, & Trabelsi, 2006; Nguyen & Nguyen, 2015; Zhang, Willison, Cox, & Hall, 1993; Zhu & Guo, 2017). The second relies on the equivalent circuit of electrical impedance spectroscopy (EIS) in which the element could also be regarded as the indicator to reveal the physical and chemical changes in agricultural products (Ando, Mizutani, & Wakatsuki, 2014; Ando, Okunishi, & Okadome, 2019), which is conducted on a full range of frequency (Ibba et al., 2020; Wu, Ogawa, & Tagawa, 2008) In the analysis of agriculture products, the equivalent circuit has shown the better ability to mirror mechanism compared with the electrical parameter method.…”