Modelling the kinetics of peroxidase inactivation, colour and texture changes of pumpkin ( Cucurbita maxima L.) during blanching

• Published in: Journal of food engineering 2007-08, Vol.81 (4), p.693-701
• Main Authors: Gonçalves, E.M., Pinheiro, J., Abreu, M., Brandão, T.R.S., Silva, C.L.M.
• Format: Article
• Language: English
• Subjects: activation energy; Biological and medical sciences; Blanching; color; Color temperature; Colour; enzyme inactivation; Food engineering; Food industries; food processing; food quality; freezing; Fruit and vegetable industries; Fundamental and applied biological sciences. Psychology; General aspects; heat inactivation; Inactivation; Kinetic models; Mathematical models; optimization; Peroxidase; prediction; process control; Pumpkin; Pumpkins; raw foods; reaction kinetics; Surface layer; temperature; Texture
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/j.jfoodeng.2007.01.011

The effects of blanching treatment on peroxidase inactivation, colour and texture of pumpkin ( Cucurbita maxima L.) were studied in the temperature range of 75–95 °C. Peroxidase inactivation followed a first-order Arrhenius model, where the activation energy and rate of the reaction at a reference temperature of 85 °C were 86.20 ± 5.57 kJ mol −1 and 0.27 ± 0.01 min −1, respectively. During blanching, pumpkin became darker and softer with processing time. The degradation of colour (evaluated throughout CIE L ∗ a ∗ b ∗ colour system, with chroma index and total colour difference) and texture parameters (firmness and energy) showed a fractional conversion model kinetics, being the temperature effect on kinetic parameters well described by the Arrhenius law. The results of this work are a good tool to further optimise pumpkin blanching conditions.