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Title:
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Changes in viscosity and pectolytic enzymes of tomato and strawberry juices processed by high-intensity pulsed electric fields
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Author:
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Aguiló-Aguayo, Ingrid; Soliva-Fortuny, Robert; Martín Belloso, Olga
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Notes:
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The effects pulse frequency (50–250 Hz), pulse width (1.0–7.0 ls) and polarity (monopolar or bipolar) of
high-intensity pulsed electric field treatments (35 kV cm)1 and 1000 ls) on viscosity and the pectin
methylesterase (PME) and polygalacturonase (PG) activities were evaluated using a response surface
methodology. Second-order expressions were accurate enough to fit experimental results. Tomato juice
apparent viscosity increased within the range of the assayed conditions, achieving the highest values at
250 Hz and 7.0 ls in bipolar mode. At the same conditions the lowest residual PME (RAPME = 10%) and
PG (RAPG = 45%) activities were observed in the juice. Apparent viscosity of strawberry juices slightly rose
when frequencies higher than 100 Hz and 1-ls monopolar pulses were applied to the juice. Treatments
causing the greatest increase in strawberry juice apparent viscosity also led to the lowest RAPME (10%) and
RAPG (75%) values. In contrast, viscosity loss was promoted under the rest of assayed HIPEF conditions
despite the low RAPME values (<20%) achieved. Moreover, RAPG did not decrease below 75% throughout
the range of studied conditions.
This work was supported by the Ministerio de Ciencia y Tecnologı´a (Spain) through the Project ALI 2005-05768. This study has also been carried out with financial support from the Commission of the European Communities, Framework 6, Priority 5 ‘Food Quality and Safety’, Integrated Project NovelQ FP6-CT-2006- 015710. I. Aguilo´ -Aguayo thanks the Ministerio de Educacio´ n y Ciencia (Spain) for the pre-doctoral grant. |
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Subject(s):
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-Pulsed electric fields
-Pectolytic enzymes
-Tomato and strawberry juices
-Viscosity |
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Rights:
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(c) Institute of Food Science and Technology, 2009
info:eu-repo/semantics/restrictedAccess |
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Document type:
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article
publishedVersion |
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Published by:
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Wiley
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