Apple Bruise Detection by Electrical Impedance Measurement
Phillipa J. Jackson, F. Roger Harker
HortScience
Abstract
Electrical impedance was used to determine the extent of tissue damage that occurred as a result of bruising of apple fruit ( Malus × domestica Borkh, cvs. Granny Smith and Splendour). Impedance measurements were made before and after bruising. Plots of reactance against resistance at 36 spot frequencies between 50 Hz and 1 MHz traced a semicircular arc, which contracted in magnitude after bruising. A number of characteristics of these curves were then related to bruise weight. The change in resistance that occurred as a result of fruit impact (ΔR 50Hz ) was the best predictor of bruise weight, with r 2 values up to 0.71. Before bruising, resistance of fruit was higher in `Splendour' than in `Granny Smith' ( P < 0.001), and at 0 °C than at 20 °C ( P < 0.001), but was not influenced by fruit weight. The influence of apple cultivar and temperature on electrical impedance may cause difficulties when implementing these measurements in a commercial situation. However, further development of electrical impedance spectroscopy methodologies may result in convenient research techniques for assessing bruise weight without having to wait for browning of the flesh.
Extracted Claims
5 claims extracted from this paper into the knowledge graph
Resistance of fruit higher at 0 °C than at 20 °C
“and at 0 °C than at 20 °C ( P < 0.001)”
Change in resistance (ΔR 50Hz) best predictor of bruise weight
“The change in resistance that occurred as a result of fruit impact (ΔR 50Hz) was the best predictor of bruise weight, with r 2 values up to 0.71.”
Resistance of fruit higher in Splendour than in Granny Smith
“Before bruising, resistance of fruit was higher in `Splendour' than in `Granny Smith' ( P < 0.001)”