Continuous microwave pasteurization of a vegetable smoothie improves its physical quality and hinders detrimental enzyme activity

  1. Mitra Arjmandi
  2. Mariano Otón
  3. Francisco Artés Calero
  4. Francisco Artés Hernández
  5. Perla Gómez
  6. Encarna Aguayo
Food science and technology international = Ciencia y tecnología de alimentos internacional

ISSN: 1082-0132 1532-1738

Year of publication: 2017

Volume: 23

Issue: 1

Pages: 36-45

Type: Article

More publications in: Food science and technology international = Ciencia y tecnología de alimentos internacional


The effect of a pasteurization treatment at 90 ± 2 ℃ for 35 s provided by continuous microwave under different doses (low power/long time and high power/short time) or conventional pasteurization on the quality of orange-colored smoothies and their changes throughout 45 days of storage at 5 ℃ was investigated. A better color retention of the microwave pasteurization- treated smoothie using high power/short time than in conventionally processed sample was evidenced by the stability of the hue angle. The continuous microwave heating increased the viscosity of the smoothie more than the conventional pasteurization in comparison with non-treated samples. Lower residual enzyme activities from peroxidase, pectin methylesterase and polygalacturonase were obtained under microwave heating, specifically due to the use of higher power/shorter time. For this kind of smoothie, polygalacturonase was the more thermo-resistant enzyme and could be used as an indicator of pasteurization efficiency. The use of a continuous semi-industrial microwave using higher power and shorter time, such as 1600 W/206 s and 3600 W/93 s, resulted in better quality smoothies and greater enzyme reduction than conventional thermal treatment.

Funding information

The authors would like to thank the Spanish Ministry of Economy and Competitiveness and the European Regional Development Fund (MINECO-FEDER, AGL2013-48830-C2-1-R) for financial support.