Carrot (Daucus carota L.) peroxidase inactivation, phenolic content and physical changes kinetics due to blanching
2010
Gonçalves, E.M. | Pinheiro, J. | Abreu, M. | Brandão, T.R.S. | Silva, C.L.M.
The kinetics of peroxidase thermal inactivation, total phenolic content degradation, and colour (CIE L∗a∗b∗) and texture changes were studied in a temperature range of 70-90°C for carrots (Daucus carota L.). Peroxidase inactivation, total phenolic content degradation and the lightness colour (L∗ parameter) change were successfully described by a first-order reaction model. The redness and yellowness colour (a∗ and b∗ parameters, respectively) and texture (firmness and energy parameters) changes presented a fractional conversion kinetic model behavior. The temperature effect was well described by the Arrhenius law. All the blanching conditions recommended to reduce peroxidase inactivation to an acceptable level (90% loss of its original activity) ensured good quality retention. However, to obtain a high quality carrot product a balance must be made between colour and total phenolic content losses. Therefore, blanching at 80°C for 6min is suggested as a compromise condition to maximize quality. The overall study indicated that colour is a critical parameter to optimize carrot hot water blanching condition.
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