Electric and mechanical detection of changes in heated apple flesh

摘要

The relationships between cell membrane damage by heating and textural parameters of apples were investigated. We determined changes in mass, volume, electrical impedance, mechanical properties, and juiciness of apple tissues after low-temperature steam heating at 40, 60, and 80 degrees C. The electrical indicator LTO was calculated from Cole-Cole plots using electrical impedance spectroscopy of apple tissues. Juiciness was estimated by measuring electrolyte release in cellular fluids during compression tests. At each temperature, the change in mass was very small compared to the sample volume. The LTO showed cell membrane damage of apples at 60 and 80 degrees C, which declined the mechanical properties, but increased juiciness. We showed that cell membrane damage affected the mechanical properties and juiciness of the heated apples. The LTO can be useful for estimation of changes in the mechanical properties and juiciness of apples during heat processing.