ABSTRACT
Fruit physiology and composition changes during their maturity and ripening process. The variation in physiological and physiochemical composition of fruits produce a change in their electrical response which can be probed by measuring the bioelectrical impedance of the fruits for their noninvasive characterization. In this direction Electrical Impedance Spectroscopy (EIS) has been applied on a number of fruits to study the physiology and ripening noninvasively. As the composition and physiological changes occurred inside the fruits varies from species to species the impedance response for different fruits will be different. A thorough study on EIS analysis on different fruits and their ripening is essential to understand the correlation between the physiological changes and the corresponding impedance response. In this paper, a technical review on the EIS techniques applied for the fruit physiology and their ripening analysis have been conducted and presented. The physiology and ripening process of a number of fruits and the relation between the fruit impedance and the ripening states are summarized. After introducing the bioimpedance and equivalent circuit modelling of fruit tissues a detail discussion has been made on the EIS technique. A detail review has been presented on the EIS based studies conducted on the fruit ripening and fruit characterization. The advantages and disadvantages of the EIS technology for fruit analysis along with the recent trends have been summarized at the end.
