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Pulsed Electric Field (pulsed + electric_field)
Selected AbstractsEFFECT OF CENTRIFUGAL FORCE ON THE AQUEOUS EXTRACTION OF SOLUTE FROM SUGAR BEET TISSUE PRETREATED BY A PULSED ELECTRIC FIELDJOURNAL OF FOOD PROCESS ENGINEERING, Issue 4 2005KAMAL EL-BELGHITI ABSTRACT In this article, the centrifugal aqueous extraction of solute from sugar beet tissue is investigated at ambient temperature after a pulsed electric field (PEF) treatment. Two kinds of samples of fresh sugar beet were used: a sample with a determined discoid shape and gratings. Both samples were pretreated by a PEF with 250 rectangular pulses of 100 µS each. The PEF intensity was fixed at 940 V/cm for the disk samples and 670 V/cm for gratings. The pretreated samples were placed in distilled water at ambient temperature with a water-to-solid ratio equal to 3 and subjected to different centrifugal accelerations. The centrifugal field significantly enhanced the kinetics of extraction from the electrically pretreated tissues of sugar beet. However, the increase of centrifugal acceleration was only effective up to a certain value (5430 × g for disk samples and 600 × g for gratings). The centrifugal extraction can be assumed to proceed in two stages: a first rapid washing followed by a slow diffusion stage. A two-exponential kinetics model taking into account these two stages was applied and correctly described the centrifugal extraction from beet samples (disks and gratings). [source] Pulsed Electric Field Processing of Beer: Microbial, Sensory, and Quality AnalysesJOURNAL OF FOOD SCIENCE, Issue 8 2004G.A. Evrendilek ABSTRACT: In this study, pulsed electric field (PEF) treatment of beer, effectiveness of PEF treatment on microbial inactivation, effects of PEF treatment on sensory properties, and detection of electrode material migration were explored. Beer samples were treated by PEF for the inactivation of natural flora and inoculated cultures of Saccaromyces uvarum, Rhodotorula rubra, Lactobacillus plantarum, Pediococcus damnosus, and Bacillus subtilis. Inactivation induced by the PEF treatment was 0.5, 4.1, 4.3, 4.7, 5.8, and 4.8 log10 colony-forming units/mL in the above microorganisms, respectively (P < 0.05). There was a significant increase in the amount of Cr, Zn, Fe, and Mn ions in the beer samples after PEF treatment (P < 0.05) leading to a statistically significant degradation in flavor and mouth feel. Further studies are needed to optimize electrode materials and PEF treatment to minimize or eliminate this degradation. [source] Photo-induced effect in quantum paraelectric materials: Transient birefringence measurementPHYSICA STATUS SOLIDI (C) - CURRENT TOPICS IN SOLID STATE PHYSICS, Issue 1 2009Y. Koyama Abstract The photo-induced effects in quantum paraelectric materials, strontium titanate SrTiO3 and Ca-doped SrTiO3, are investigated. The observed birefringence for Cadoped SrTiO3 shows that an optical anisotropy along the [100] axis is generated by the ultraviolet (UV) illumination. The transient birefringence in a pulsed electric field is studied to probe the dynamical property of the polarization under dark and UV illumination. Under the UV illumination, the change of birefringence is reduced, and the dielectric response of relaxation type was observed both in SrTiO3 and in Ca-doped SrTiO3. It was found that the ferroelectric phase transition temperature is shifted toward the lower temperature side under the UV illumination. (© 2009 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim) [source] Prolonging microbial shelf life of foods through the use of natural compounds and non-thermal approaches , a reviewINTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 2 2009Maria Rosaria Corbo Summary This paper proposes a review of some alternative approaches for food stabilisation and shelf life prolonging (based on the use of natural compounds and/or non-thermal techniques). After a brief description of food structure implication on the way of using the alternative approaches, two paragraphs summarise the topics of natural molecules (essential oils, lysozyme, lactoferrin and lactoperoxidase system, fatty acids, chitosan) and non-thermal approaches (high hydrostatic and homogenisation pressures, pulsed electric fields, high power ultrasound and irradiation). Finally, the last sections deal with the use of combined hurdles (along with the proposal of three possible modes of action of a multi-target preservation), the mathematical approaches for shelf life evaluating and some critical issues to be addressed in the future for a real scaling up of the proposed techniques. [source] | ||||||||||