Main objective was the development of a non-contact measurement technique to determine the decayed proportion of apples. Using impedance measurements enables measuring the proportion of damaged cells in biological tissue depending on the frequency. The measurements with the coil system showed dependence on the mass and on the apple variety. With increasing decay the voltage signal also increased. Healthy apples can be distinguished statistically sure of partially decayed apples from a decayed part of 16.3%. It did not matter if the variety was considered.

The main objective of this work was to determine if it is possible to distinguish between intact and destroyed apple tissue with an inductively working coil system. With conductive measurement, it is possible to measure the amount of destroyed cell in plant tissues. Destroyed cells in plant tissue can mean bad quality for the particular product. The advantage of the inductive measuring technique is the possibility to measure the complete product contactless and nondestructively during the production process. Hence, an inline measurement system could be developed.In order to destroy cells in apples, a freeze-thaw cycle was subjected to three different apples varieties (Braeburn, Jonagold and Idared). The changes of the electrical parameters were observed before and after the thermal treatment.It could be demonstrated that the inductive measuring leads to similar statements as conductive measuring methods. The electrical parameters showed mass dependent. Hence, the electrical parameters had to be normalized to the sample mass. The mass normalized voltage U B,normalized is well suited to describe the cell destruction. It could be shown that the cell destruction provides higher U B,normalized -values.