Isothermal calorimetry approach to evaluate tissue damage in carrot slices upon thermal processing

The purpose of this investigation was to test calorimetry as a means of quantifying cell damage occurring at various stages of mild blanching treatments. Calorimetric measurements were carried out on cores taken from carrot slices blanched at 100 degreesC for 5-45 s. The calorimetric data were corrected for the influence of wounding stress due to slicing and coring. The validity of calorimetry to measure cell damage was assessed by simulating inactivation of cell metabolism based on bibliographic data on thermal inactivation kinetics of plasma membrane H+-ATPase, used as a marker of overall cell membrane damage. Calorimetric data paralleled the simulated decrease of actively metabolizing cells only in the first 20 s of blanching but diverged at higher blanching times. Our results suggest that inactivation of enzymes responsible for quality-related changes during frozen storage (e.g. blanching at 100 degreesC for 20 s) may be accompanied by cell damage in about 70% of the tissue. (C) 2004 Elsevier Ltd. All rights reserved.