CHARACTERIZATION OF OSMOTIC DEHYDRATION AND SWELLING OF APPLE TISSUES BY BIOELECTRICAL IMPEDANCE SPECTROSCOPY

摘要

The electrical impedance of apple strip samples immersed in osmotic medium wasrninvestigated to characterize a dehydration process with sucrose solution and a swellingrn(hydration) process with deionized distilled water. The impedance measured atrnfrequencies of 10 Hz to 100 kHz could be fitted well by an electrical equivalent modelrn'Hayden model'. Symplasmic (intracellular) resistance and apoplasmic (extracellular)rnresistance assumed in the model showed a specific increase or decrease whichrncorresponded to a dehydration or swelling (hydration) process respectively.rnConsequently, the changes in the resistances were suggested to be caused by an increasernor a decrease in moisture content in extracellular and intracellular volumes.rnFurthermore, the time variation of the resistance values could be representedrnapproximately by a first-order response equation. Therefore, it was concluded thatrnbioelectrical impedance spectroscopy (BIS) was applicable to the simple detection ofrndehydration and swelling and that it was a helpful and effective method to monitorrndehydration and swelling processes nondestructively and continuously.