Thermal Inactivation at High Temperatures and Regeneration of Green Asparagus Peroxidase

A spectrophotometric method was developed for determining the peroxidase activity of green asparagus in small samples. The optimum conditions for the analysis in the cuvette were 45 mM of H2O2 36 mM of guaiacol, and pH 7. The method can be used to determine enzyme activity at up to two decimal reductions. A study was performed of the regeneration and inactivation kinetics of the enzyme when heated between 90 and 125°C. Regenerated asparagus peroxidase reached its maximum activity after being stored 6 days at 25°C. The regenerated enzyme followed first-order inactivation kinetics, showing an Ea = 13.62 kcal/mol and k100°C = 2.07 min−1.

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Thermal Inactivation Kinetics of Sporolactobacillus nakayamae Spores, a Spoilage Bacterium Isolated from a Model Mashed Potato–Scallion Mixture

Journal of Food Protection ◽

10.4315/0362-028x.jfp-16-103 ◽

2016 ◽

Vol 79 (9) ◽

pp. 1482-1489

Author(s):

HAYRIYE BOZKURT ◽

JAIRUS R. D. DAVID ◽

RYAN J. TALLEY ◽

D. SCOTT LINEBACK ◽

P. MICHAEL DAVIDSON

Keyword(s):

Heat Resistance ◽

Thermal Inactivation ◽

Weibull Model ◽

Inactivation Kinetics ◽

Order Model ◽

First Order ◽

Different Temperatures ◽

Spoilage Bacterium ◽

D Values ◽

Kinetics Of

ABSTRACT Sporolactobacillus species have been occasionally isolated from spoiled foods and environmental sources. Thus, food processors should be aware of their potential presence and characteristics. In this study, the heat resistance and influence of the growth and recovery media on apparent heat resistance of Sporolactobacillus nakayamae spores were studied and described mathematically. For each medium, survivor curves and thermal death curves were generated for different treatment times (0 to 25 min) at different temperatures (70, 75, and 80°C) and Weibull and first-order models were compared. Thermal inactivation data for S. nakayamae spores varied widely depending on the media formulations used, with glucose yeast peptone consistently yielding the highest D-values for the three temperatures tested. For this same medium, the D-values ranged from 25.24 ± 1.57 to 3.45 ± 0.27 min for the first-order model and from 24.18 ± 0.62 to 3.50 ± 0.24 min for the Weibull model at 70 and 80°C, respectively. The z-values determined for S. nakayamae spores were 11.91 ± 0.29°C for the Weibull model and 11.58 ± 0.43°C for the first-order model. The calculated activation energy was 200.5 ± 7.3 kJ/mol for the first-order model and 192.8 ± 22.1 kJ/mol for the Weibull model. The Weibull model consistently produced the best fit for all the survival curves. This study provides novel and precise information on thermal inactivation kinetics of S. nakayamae spores that will enable reliable thermal process calculations for eliminating this spoilage bacterium.

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Thermal Inactivation Kinetics of Human Norovirus Surrogates and Hepatitis A Virus in Turkey Deli Meat

Applied and Environmental Microbiology ◽

10.1128/aem.00874-15 ◽

2015 ◽

Vol 81 (14) ◽

pp. 4850-4859 ◽

Cited By ~ 10

Author(s):

Hayriye Bozkurt ◽

Doris H. D'Souza ◽

P. Michael Davidson

Keyword(s):

Hepatitis A ◽

Thermal Inactivation ◽

Hepatitis A Virus ◽

Weibull Model ◽

Activation Energies ◽

Inactivation Kinetics ◽

Order Model ◽

Decimal Reduction Time ◽

First Order ◽

Kinetics Of

ABSTRACTHuman noroviruses (HNoV) and hepatitis A virus (HAV) have been implicated in outbreaks linked to the consumption of presliced ready-to-eat deli meats. The objectives of this research were to determine the thermal inactivation kinetics of HNoV surrogates (murine norovirus 1 [MNV-1] and feline calicivirus strain F9 [FCV-F9]) and HAV in turkey deli meat, compare first-order and Weibull models to describe the data, and calculate Arrhenius activation energy values for each model. TheD(decimal reduction time) values in the temperature range of 50 to 72°C calculated from the first-order model were 0.1 ± 0.0 to 9.9 ± 3.9 min for FCV-F9, 0.2 ± 0.0 to 21.0 ± 0.8 min for MNV-1, and 1.0 ± 0.1 to 42.0 ± 5.6 min for HAV. Using the Weibull model, thetD = 1(time to destroy 1 log) values for FCV-F9, MNV-1, and HAV at the same temperatures ranged from 0.1 ± 0.0 to 11.9 ± 5.1 min, from 0.3 ± 0.1 to 17.8 ± 1.8 min, and from 0.6 ± 0.3 to 25.9 ± 3.7 min, respectively. Thez(thermal resistance) values for FCV-F9, MNV-1, and HAV were 11.3 ± 2.1°C, 11.0 ± 1.6°C, and 13.4 ± 2.6°C, respectively, using the Weibull model. Thezvalues using the first-order model were 11.9 ± 1.0°C, 10.9 ± 1.3°C, and 12.8 ± 1.7°C for FCV-F9, MNV-1, and HAV, respectively. For the Weibull model, estimated activation energies for FCV-F9, MNV-1, and HAV were 214 ± 28, 242 ± 36, and 154 ± 19 kJ/mole, respectively, while the calculated activation energies for the first-order model were 181 ± 16, 196 ± 5, and 167 ± 9 kJ/mole, respectively. Precise information on the thermal inactivation of HNoV surrogates and HAV in turkey deli meat was generated. This provided calculations of parameters for more-reliable thermal processes to inactivate viruses in contaminated presliced ready-to-eat deli meats and thus to reduce the risk of foodborne illness outbreaks.

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Inactivation and Regeneration Kinetics of Horseradish Peroxidase Heated at High Temperatures

Journal of Food Protection ◽

10.4315/0362-028x-60.8.961 ◽

1997 ◽

Vol 60 (8) ◽

pp. 961-966 ◽

Cited By ~ 12

Author(s):

CARMEN RODRIGO ◽

MIGUEL RODRIGO ◽

ANDRÉS ALVARRUIZ ◽

ANA FRÍGOLA

Keyword(s):

Horseradish Peroxidase ◽

High Temperatures ◽

Storage Temperature ◽

Maximum Activity ◽

Inactivation Kinetics ◽

Capillary Tubes ◽

Absolute Value ◽

First Order ◽

The Absolute ◽

Kinetics Of

The inactivation kinetics of horseradish peroxidase (HRP) heated in capillary tubes in the range 110 to 135°C was studied. Its regeneration kinetics when stored at 4 and 25°C was also considered. As the severity of the treatment increased, the absolute value of the regeneration decreased. The storage temperature of the enzyme did not affect the percentage of maximum activity regenerable, although when this temperature was raised from 4 to 25°C the speed of regeneration increased. Kinetics of HRP inactivation determined after heating and after regeneration were compared. Both forms of the enzyme showed similar behavior with first-order inactivation kinetics, with Ea = 19.5 ± 1.0 kcal/mol and k120°C = 3.7 ± 0.2 min−1, and Ea = 18.8 ± 1.2 kcal/mol and k120°C = 3.7 ± 0.2 min−1, respectively.

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Saccharomyces cerevisiae Thermal Inactivation Kinetics Combined with Ultrasound

Journal of Food Protection ◽

10.4315/0362-028x-62.10.1215 ◽

1999 ◽

Vol 62 (10) ◽

pp. 1215-1217 ◽

Cited By ~ 50

Author(s):

A. LÓPEZ-MALO ◽

S. GUERRERO ◽

S. M. ALZAMORA

Keyword(s):

Saccharomyces Cerevisiae ◽

Thermal Inactivation ◽

Order Reaction ◽

Heat Inactivation ◽

Inactivation Kinetics ◽

Thermal Treatments ◽

Combined Treatments ◽

First Order ◽

D Values ◽

Kinetics Of

Inactivation kinetics of Saccharomyces cerevisiae during thermal treatments at moderate temperatures (45.0, 47.5, 50.0, 52.5, or 55.0°C) combined with application of 20 kHz of ultrasound were evaluated. S. cerevisiae inactivation under the combined effects of heat and ultrasound followed first-order reaction kinetics, with decimal reduction times (D) that varied from 22.3 to 0.8 min. D values in treatments that combined heat and ultrasound were significantly smaller (P < 0.05) than D values obtained for thermal treatments and were more noticeable at temperatures below 50°C. The dependence of the D value on temperature had a significantly (P < 0.05) greater z value for combined treatments. Yeast heat inactivation kinetics revealed decreased thermal resistance caused by ultrasound.

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Determination of the Thermal Inactivation Kinetics of the Human Norovirus Surrogates, Murine Norovirus and Feline Calicivirus

Journal of Food Protection ◽

10.4315/0362-028x.jfp-12-327 ◽

2013 ◽

Vol 76 (1) ◽

pp. 79-84 ◽

Cited By ~ 36

Author(s):

HAYRIYE BOZKURT ◽

DORIS H. D'SOUZA ◽

P. MICHAEL DAVIDSON

Keyword(s):

Thermal Inactivation ◽

Weibull Model ◽

Inactivation Kinetics ◽

Feline Calicivirus ◽

Murine Norovirus ◽

Order Model ◽

Human Norovirus ◽

First Order ◽

D Values ◽

Kinetics Of

Studies are needed to bridge existing data gaps and determine appropriate parameters for thermal inactivation methods for human noroviruses. Cultivable surrogates, such as feline calicivirus (FCV-F9) and murine norovirus (MNV-1), have been used in the absence of human norovirus infectivity assays. This study aimed to characterize the thermal inactivation kinetics of MNV-1 and FCV-F9 at 50, 56, 60, 65, and 72°C for different treatment times (0 to 60 min). Thermal inactivation was performed using the capillary tube method with titers of 4.0 × 107 (MNV-1) and 5.8 × 108 (FCV-F9) PFU/ml in triplicate experiments, followed by standard plaque assays in duplicate for each experiment. Weibull and first-order models were compared to describe survival curve kinetics. Model fitness was investigated by comparing the regression coefficients (R2) and the chi-square (χ2) and root mean square error (RMSE) values. The D-values calculated from the first-order model (50 to 72°C) were 0.15 to 34.49 min for MNV-1 and 0.11 to 20.23 min for FCV-9. Using the Weibull model, the tD values needed to destroy 1 log PFU of MNV-1 and FCV-F9 at the same temperatures were 0.11 to 28.26 and 0.06 to 13.86 min, respectively. In terms of thermal resistance, MNV-1 was more sensitive than FCV-F9 up to 65°C. At 72°C, FCV-F9 was slightly more susceptible to heat inactivation. Results revealed that the Weibull model was more appropriate to represent the thermal inactivation behavior of both tested surrogates. The z-values were calculated using D-values for the first-order model and the tD values for the Weibull model. The z-values were 9.31 and 9.19°C for MNV-1 and 9.36 and 9.31°C for FCV-F9 for the first-order and Weibull models, respectively. This study provides more precise information than previous reports on the thermal inactivation kinetics of two norovirus surrogates for use in thermal process calculations.

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High-Temperature Short-Time Inactivation of Peroxidase by Direct Heating with a Five-Channel Computer-Controlled Thermoresistometer†

Journal of Food Protection ◽

10.4315/0362-028x-60.8.967 ◽

1997 ◽

Vol 60 (8) ◽

pp. 967-972 ◽

Cited By ~ 9

Author(s):

CARMEN RODRIGO ◽

ANDRÉS ALVARRUIZ ◽

ANTONIO MARTÍNEZ ◽

ANA FRÍGOLA ◽

MIGUEL RODRIGO

Keyword(s):

High Temperature ◽

Horseradish Peroxidase ◽

Thermal Inactivation ◽

Inactivation Kinetics ◽

First Order ◽

First Order Kinetics ◽

High Temperature Short Time ◽

Computer Controlled ◽

Short Time ◽

Kinetics Of

The thermal inactivation kinetics of horseradish and asparagus peroxidase in high-temperature short-time conditions was studied by heating in a five-channel computer-controlled thermoresistometer. Horseradish peroxidase was heated between 111.5 and 145°C and the reaction was analyzed assuming that two isoenzymes with EaL = 44.1 and Eas = 22.0 kcal/mol were present. Asparagus peroxidase heated from 110 to l20°C reacted with first-order kinetics, with Ea = 20 kcal/mol. The five-channel computer-controlled thermoresistometer enabled us to study the inactivation kinetics of the more labile fraction of horseradish peroxidase at temperatures above 100°C; this equipment was suitable for studying the heat resistance of peroxidase at high temperatures.

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