Low temperature blanching effect on the changes in mechanical properties during subsequent cooking of three potato cultivars

Eight mechanical properties of three potato cultivars were measured during low-temperature blanching (55, 65 and 75 degrees C) and subsequent cooling and cooking treatments. The mechanical properties were determined with a ri ng tensile test. Force-based properties showed a decrease in value during b lanching and cooking, whereas deformation-based properties showed an initia l increase during blanching, before decreasing, during cooking or after lon ger blanching times. This behaviour was attributed to the loss of turgor of the fresh potato tissue. Rates of change of mechanical properties during c ooking depended on the pre-blanching treatments: longer blanching times res ulted in a slower decrease of the mechanical properties. The overall behavi our during blanching and cooking of the three cultivars was similar. A prin cipal component analysis on the measured mechanical properties, for each bl anching temperature separately, was used to study the blanching temperature effect and to segregate potato cultivars on their cooking behaviour.