Lysozyme is considered as part of the innate immune system. It has stimulated considerable interest as a natural food preservative. Lysozyme has been shown to be effective in preserving a variety of foods such as fresh fruits and vegetables, meats, seafood and wine, for which many Japanese patents have been granted. The relatively high THERMAL stability of lysozyme also makes it attractive for use in pasteurized and heat-sterilized food products, possibly allowing reduced THERMAL processes, and therefore, minimized nutritional and sensory quality loss. In this study, we investigated effect of polyamines on the THERMAL INACTIVATION of lysozyme by kinetics curves. Our results showed that polyamines can decrease the THERMAL INACTIVATION of lysozyme, the effect of spermine on the THERMAL INACTIVATION of lysozyme was more than that of the spermidine.

Background and objectives: Turbidity is a desirable property in some juices such as carrotkiwi juice that is influenced by the presence of released pectin. Pectin methylesterase (PME) causes turbidity loss in the juice because of desterification of the pectin. THERMAL processing is the most common method to PME INACTIVATION. The aim of this study was investigation of PME INACTIVATION during THERMAL processing of carrot-kiwi juice at different temperature. Materials and methods: To study the PME INACTIVATION, the carrot-kiwi juice was heated at 60, 70, 80 and 90 ℃ at different time (proportional to the temperature). D and Z-value and THERMAL dependence kinetic parameters consisting of activation energy (Ea), enthalpy (Δ H), entropy (Δ S) and free energy (Δ G) of the THERMAL INACTIVATION of PME were calculated. Results: Based on the obtained results, the Z-values of heat sensitive and heat resistant isoforms of PME in the juice during processing at 60, 70, 80 and 90 ° C were calculeted 17. 85 ° C and 22. 27 ° C, respectively. The required Ea to inactivate the heat sensitive and heat resistant isoforms of PME in the carrot-kiwi juice were 356. 83 kJ/mol and 257. 17 kJ/mol, respectively. Also, enthalpy for INACTIVATION of the heat sensitive and heat resistant isoforms ranged between 354. 1 to 353. 8 kJ. mol-1 and 254. 4 to 254. 1 kJ. mol-1, respectively. During the juice THERMAL processing, the entropy of the INACTIVATION of the heat sensitive and heat resistant isoforms were calculated 0. 79 to 0. 73 K-1. kJ. mol-1 and 0. 47 to 0. 43 K-1. kJ. mol-1, respectively. The free energy related to the INACTIVATION of the heat sensitive (91. 1 to 87. 3 kJ. mol-1) and heat resistant (97. 9 to 97. 0 kJ. mol-1) isoforms of PME were measured. These results represent the effect of temperature on the protein structure of the PME. In addition, the effectiveness percentage of the come up time (CUT) on INACTIVATION of the heat sensitive and heat resistant isoforms of PME in the carrot-kiwi juice were computed. Conclusion: By considering the effect of come up time and THERMAL resistance of the heat sensitive isoform of PME, the required pasteurization time for carrot-kiwi juice at 75, 80, 85, 90 and 95 ℃ were 22. 14, 11. 61, 6. 09, 3. 19 and 2. 01 min, respectively.

In this work, Picard iteration method is used to obtain analytical expressions for the prediction of molar concentration of native and denatured jack bean urease (EC 3. 5. 1. 5) through the three-reaction steps kinetic model of THERMAL INACTIVATION of the urease. The obtained solutions are used to study the kinetics of THERMAL INACTIVATION of the enzyme as applied in biotechnology. The analytical solutions are verified with numerical solutions using Runge – Kutta with shooting method and good agreements are established between the solutions. From the parametric studies using the iterative method, the molar concentration of native enzyme decreases as the time increases while the molar concentration of the denatured enzyme increases as the time increases. The time taken to reach the maximum value of the molar concentration of native enzyme is the same as the time taken to reach the minimum value of the molar concentration of the denature enzyme. The information given in this theoretical investigation will assist in the kinetic analysis of the experimental results over handling rate constants and molar concentrations.

Background and Objectives: Proxidase enzyme is one of the most important enzymes in plant tissues, which can bind to hydrogen peroxide and produce an activated complex that can react with a wide range of donor molecules. Therefore, INACTIVATION of the enzyme may increase the shelf life of raw and un-blanched frozen vegetables. In order to inactivate the enzyme methods such as heating, lowering pH oraw or adding chemical additives (SO2) can be used; however, each of the above mentioned methods has a kind of shortcoming. Nowadays consumer's trend has been oriented to use fresh products or foods prepared by little process, therefore producers are interested in using alternative methods in order that increase the product’s shelf life.Materials and Methods: In this study the effect of natural essential oils (Golpar, Thyme and Clove oils) on peroxidase enzyme activity was investigated. Optimization of peroxidase enzyme INACTIVATION under different variables (essential oils concentration, the time of enzyme activity, blanching time and temperature) was performed using response surface methodology.Results: The results showed that peroxidase activity of celery extracts was affected by all the studied oils and its activity was reduced. Optimum conditions for non-THERMAL INACTIVATION of peroxidase enzyme of celery for different used oils were as: Golpar concentration 50 ppm, the time of enzyme activity 60 seconds, and enzyme activity (absorption) 0.467599; Thyme concentration 50 ppm, the time of enzyme activity 60 seconds and enzyme activity (absorption) 0.0523847; and clove oil concentration 50 ppm, the time of enzyme activity 60 seconds and enzyme activity (absorption) 0.120615.Conclusion: This study showed that essential oils have the ability to inhibit and inactivate peroxidase enzyme activity.

Aim: The role of Hsp70 chaperone from Rutilus frisii kutum in the THERMAL INACTIVATION of luciferase in E. coli cell carrying Hsp70 and firefly luciferase was investigated. Material and Methods: Co-transformation of E. coli cell was carried out with two expression vectors containing Hsp70 and firefly luciferase. The co-transformed cells carrying Hsp70 and luciferase were expressed under optimum conditions. After adding tetracycline, the cells were then incubated for 60 min at 40, 42, 44, 46, 48 and 50° C treatments. Finally, the luminescence activity of samples was calculated. Results: After 30 min at 40 and 42° C temperatures, the luciferase activity in control samples reached almost zero, while in the co-transformed samples, about 72% and 60% of the luminance activity maintained compared with control samples (before heat treatment), and even after 60 min, up to 36% and 22% of the activity remained. Also, at 44 and 46° C temperatures in the initial times after stress, a significant difference was observed between the luciferase activity of the co-transformed and the control samples. In contrast, at 48 and 50° C temperatures, the changes of the luciferase activity of co-transformed samples were small compared with control samples even in the early stages of stress. Conclusion: The THERMAL aggregation of luciferase as a significant reporter protein is inhibited at high temperatures via the activity of Hsp70 in the bacterial cell, which this process can be widely used in the food and pharmaceutical industries and the providing cancer diagnostic kits.

Increasing consumer awareness of the dangers of chemicals and the effect of heat treatment on the foods nutritional value, lead to increase of the demand for the production and use of fresh or minimaly processed foods. In this study, the ability of cumin, fennel and clove essential oils (concentrations of 50, 75, 100, 200 ppm and pure form) in non-THERMAL INACTIVATION of courgette peroxidase enzyme were investigated. The results showed that only pure form and concentration of 200 ppm of cumin essential oil and also pure form and high concentrations (100 and 200 ppm) of fennel essential oil were able to reduce the peroxidase enzyme activity in courgette but using concentrations of 50 and 75 ppm of fennel essential oil leads to increase peroxidase enzyme activity. Clove essential oil in all studied concentrations reduced the peroxidase enzyme activity, which indicates the ability of clove essential oil to react with oxygen and inhibit the reaction of enzyme peroxidase and polyphenol oxidase (enzymatic browning reaction). The best conditions for INACTIVATION of peroxidase enzyme under the influence of cumin essential oil included a concentration of 194. 5 ppm essential oil and an enzymatic activity time of 0. 02 seconds, while the optimal conditions for achieving the lowest peroxidase activity included using 200 ppm fennel essential oil and enzyme activity time of 0 second, and 200 ppm of clove essential oil and enzymatic activity time of 1. 7 second.