Preliminary studies on infrared blanching of carrot slices
(5 mm) were carried out to determine time and temperature
combination to inactivate peroxidase enzyme to the desired
level (10% of the initial activity). Since, peroxidase enzyme
is highly heat stable and complete inactivation takes longer
time, 90% of the initial value of peroxidase enzyme inactivation
is considered to be adequate for all practical purposes
(Ramesh et al., 2002). The qualitative analysis showed the
desired level of inactivation of peroxidase when the zone
temperature was in the range of 180–240 ◦C. The operating
conditions, time required for blanching and corresponding
residual peroxidase activity are presented in Table 1.