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A. VAN LOEY A. FRANSIS M. HENDRICKX G. MAESMANS J. de NORONHA P. TOBBACK 《Journal of food science》1994,59(4):828-832
Based on thermal degradation kinetics and heat transfer expressed as the Ball formula method, a simplified approach was used to optimize sterilization processes for thermal softening of white beans (Phaseolus vulgaris, subsp. nanus Metz., variety Manteca de Leon) Constant retort profiles in a still and end-over-end rotary water cascading retort (Barriquand Steriflow) were used. Quality attributes of beans processed at the optimum were evaluated by a trained taste panel and by a tenderometer. Both approaches could distinguish (P<0.01) between attributes of products from optimal rotary and still processes. End-over-end rotation resulted in faster heat penetration and better quality retention of beans. Texture of white beans processed at 4° or 8°C from the optimal temperature could be distinguished (P<0.01) by the sensory panel and by the tenderometer. 相似文献
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SUSANNA DE CORDT MARC HENDRICKX GEERT MAESMANS PAUL TOBBACK 《International Journal of Food Science & Technology》1992,27(6):661-673
Biphasic and nth-order models were tested as to their usefulness to fit experimental inactivation data of Bacillus licheniformis α-amylase, immobilized on glass beads, and were discussed with respect to their suitability to characterize the considered enzymic system as a time—temperature integrator (TTI) to evaluate heat processes. Both isothermal and non-isothermal inactivation experiments were carried out. Model (kinetic) parameters (rate constant k, activation energy EA and reaction order n) were estimated using a non-linear regression procedure. The results obtained, especially the activation energy of about 293 kJ mole–1 , indicated a potential use of this system as a TTI for heating processes in the temperature range of 96–108°C. 相似文献
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A. VAN LOEY A. FRANSIS M. HENDRICKX G. MAESMANS P. TOBBACK 《Journal of Food Processing and Preservation》1994,18(5):407-420
The temperature dependence of the rate index of thermal softening of white beans ( Phaseolus vulgaris , subsp. nanus Metz. variety Manteca de Leon ) was determined within the temperature range of 90C to 122C using an industrial FMC tenderometer and a trained sensory panel. Based on sensorial results a first order reaction was assumed, whereas the tenderometer values were described by a biphasic model. Using a multiple linear regression analysis on the sensorial data, the activation energy for the heat induced firmness degradation of beans was calculated as 130.8 kJ/mole. Activation energies of both phases of the biphasic model were obtained by a two-step linear regression on the tenderometer data. Activation energies of both phases were equal, namely 105.1 kJ/mole. 相似文献
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M. HENDRICKX† Z. WENG G. MAESMANS P. TOBBACK 《International Journal of Food Science & Technology》1992,27(1):21-31
In this work, a general theory for the development of a Time Temperature Integrator, TTI-system, is outlined. A z-value (or activation energy) of the TTI-system equal to that of target index is crucial for the usefulness of a system to monitor the impact of thermal processes on foods. The proposed TTI, namely the heat-stable fraction of peroxidase covalently immobilized on porous glass beads in dodecane, can be used to indicate the intensity of a delivered pasteurization process when a z-value of 10°C is used for calculating the lethality. Lethalities read from the bio-indicator showed excellent agreement with those integrated from the measured time-temperature data. 相似文献
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G. MAESMANS M. HENDRICKX S. de CORDT P. TOBBACK 《Journal of Food Processing and Preservation》1993,17(5):369-389
Recently, the use of Time Temperature Integrators (TTIs) as an alternative means of process evaluation, besides in situ process monitoring and the physical-mathematical method, has received a lot of attention. the stringent requirement to which an adequate functioning TTI should respond, i.e. , the temperature dependence of reaction rate constants for the monitored target quality attribute and the TTI shall be identical, is hard to realize in practice. Therefore, multicomponent TTIs have been suggested to evaluate the integrated impact of time and temperature on a target quality attribute. These monitoring devices consist of a number of temperature sensitive units, each with its own response of reaction rates to temperature. the question how from the combined reading of these individual systems, the impact of the heating process on a target quality parameter can be predicted has not yet been answered.
In this theoretical study, we critically consider the restrictions of two interpolation methods in determining the impact on a target quality attribute from the reading of three other temperature sensitive systems. Possibilities of the 'Equivalent Point Method'and a polynomial expression as interpolation method are tested. Success of these transformations depends on kinetic characteristics of the components in the multicomponent TTI system and the actual product temperature history. Since only limited information is available on the product temperature 相似文献
In this theoretical study, we critically consider the restrictions of two interpolation methods in determining the impact on a target quality attribute from the reading of three other temperature sensitive systems. Possibilities of the 'Equivalent Point Method'and a polynomial expression as interpolation method are tested. Success of these transformations depends on kinetic characteristics of the components in the multicomponent TTI system and the actual product temperature history. Since only limited information is available on the product temperature 相似文献
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Immobilized Peroxidase: A Potential Bioindicator for Evaluation of Thermal Processes 总被引:1,自引:0,他引:1
The heat-stable fraction of covalently immobilized peroxidase on/in porous glass beads in an environment of dodecane was studied as a bioindicator for evaluation of thermal processes under conditions of pasteurization. The verified bioindicator had a z value of 10.1°C and a Dref (at 70°C) of 22 min. At processing temperatures of 70°C and 80°C, the lethalities (F)bio as read from the bioindicator agreed very well with the target Ft10.0 values calculated from the time temperature data according to the general method. 相似文献
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ZHIJUN WENG M. HENDRICKX G. MAESMANS K. GEBRUERS P. TOBBACK 《Journal of food science》1991,56(2):574-578
Thermal inactivation kinetics of soluble horseradish peroxidase and the enzyme covalently immobilized onto glass beads were studied in phosphate buffer and organic solvents in a temperature range of 65° to 98°C. The z value of the heat-stable fraction of peroxidase was changed from 26.3°C to 14.1°C by the method of enzyme immobilization. Further, the z value of 14.1°C of the immobilized peroxidase was lowered to 11.1°C using an organic solvent in order to modify the environment of the enzyme. 相似文献
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