Inactivation Kinetics of Pectin Methylesterase, Polyphenol Oxidase, and Peroxidase in Cloudy Apple Juice under Microwave and Conventional Heating to Evaluate Non-Thermal Microwave Effects
- 216 Downloads
Continuous-flow microwave pasteurization provides important advantages over conventional heat exchangers such as fast volumetric heating, lower tube surface temperature, and possible non-thermal effects that enhance enzymatic and bacterial inactivation. Conventional and microwave-assisted inactivation of pectin methylesterase (PME), polyphenol oxidase (PPO), and peroxidase (POD) in cloudy apple juice were investigated to evaluate non-thermal effects. Experiments were conducted to provide uniform heating with accurate temperature acquisition and similar temperature profiles for conventional and microwave treatments. A two-fraction first-order kinetic model was successfully fitted to the data in a procedure that took into account the whole time-temperature profile instead of assuming isothermal conditions. Predicted inactivation curves for pasteurization at 70 and 80 °C of the cloudy apple juice showed that PME has the highest thermal resistance (residual activity of 30% after 250 s at 80 °C) and that there was no evidence of non-thermal microwave effects on the inactivation of these enzymes.
KeywordsApple juice Enzyme Microwave Pasteurization Kinetic
The authors acknowledge financial support from the São Paulo Research Foundation—FAPESP (grants 2013/07914-8, 2014/06026-4, and 2014/17534-0) and from the National Council for Scientific and Technological Development—CNPq (grant 459177/2014-1) and also Prof. Adalberto Pessoa Junior from the Faculty of Pharmaceutical Sciences at the University of São Paulo for access to their facilities.
- AOAC. (2010). Official methods of analysis of AOAC international (18th ed.). Washington, DC: AOAC, Association of official analytical chemists.Google Scholar
- Arjmandi, M., Otón, M., Artés, F., Artés-Hernández, F., Gómez, P. A., & Aguayo, E. (2017). Microwave flow and conventional heating effects on the physicochemical properties, bioactive compounds and enzymatic activity of tomato puree. Journal of the Science of Food and Agriculture, 97(3), 984–990.CrossRefPubMedGoogle Scholar
- Falguera, V., Gatius, F., Ibarz, A., & Barbosa-Cánovas, G. V. (2013). Kinetic and multivariate analysis of polyphenol oxidase inactivation by high pressure and temperature processing in apple juices made from six different varieties. Food and Bioprocess Technology, 6(9), 2342–2352.CrossRefGoogle Scholar
- Latorre, M. E., Bonelli, P. R., Rojas, A. M., & Gerschenson, L. N. (2012). Microwave inactivation of red beet (Beta vulgaris L. var. conditiva) peroxidase and polyphenoloxidase and the effect of radiation on vegetable tissue quality. Journal of Food Engineering, 109(4), 676–684.CrossRefGoogle Scholar
- Lopes, L. C., Barreto, M. T., Goncalves, K. M., Alvarez, H. M., Heredia, M. F., de Souza, R. O. M., Cordeiro, Y., Dariva, C., & Fricks, A. T. (2015). Stability and structural changes of horseradish peroxidase: microwave versus conventional heating treatment. Enzyme and Microbial Technology, 69, 10–18.CrossRefPubMedGoogle Scholar
- Matsui, K. N. (2006). Inativação das enzimas presentes na água de coco verde (Cocos nucifera L.) por processo térmico através de micro-ondas (Doctoral dissertation). Retrieved from Teses USP Database. https://doi.org/10.11606/T.3.2006-180716.
- Rawson, A., Patras, A., Tiwari, B. K., Noci, F., Koutchma, T., & Brunton, N. (2011). Effect of thermal and non thermal processing technologies on the bioactive content of exotic fruits and their products: review of recent advances. Food Research International, 44(7), 1875–1887.CrossRefGoogle Scholar
- Rouse, A. H., & Atkins, C. D. (1953). Further results from a study on heat inactivation of pectinesterase in citrus juices. Food Technology, 7(6), 221–223.Google Scholar
- Sinha, N. K. (2006). Apples. In Y. H. Hui (Ed.), Handbook of fruits and fruit processing (pp. 265–278). Hoboken: Blackwell Publishing.Google Scholar