List of Articles Degradation Kinetics

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  1 - Simultaneous Effect of Temperature and Hydrogen Peroxid on Degradation of Anthocyanins in Three Berberis Species Juices
  M. Farhadi Chitgar M. Varidi F. Shahidi A. Torabi
  Introduction: Antocyanins provide a pleasant and attractive appearance in fruits and vegetables particularly fruit juices. Therefore it is necessary to study the effect of hydrogen peroxide (H2O2) as a widespread material in packaging sterilant in aseptic processing sys More

  Introduction: Antocyanins provide a pleasant and attractive appearance in fruits and vegetables particularly fruit juices. Therefore it is necessary to study the effect of hydrogen peroxide (H2O2) as a widespread material in packaging sterilant in aseptic processing systems on anthocyanins from various juices. Materials and Methods: In this study, the simultaneous effect of hydrogen peroxide in five different concentrations and three different temperatures (10, 15, 20, 25 and 30 mmol/L) and (10, 20 and 30 ̊C) on degradation of anthocyanins in Berberis vulgaris, Berberis cratagina and Beberis integerrima juices have been investigated. Results: The degradation of anthocyanins in all treatments were fitted both zero and first order kinetics models. The results showed the degradation of anthocyanins in these three Berberis juices followed the first-order reaction kinetics. In most cases, the reaction rate constant (k) and half-life (t1/2) differed significantly among the three Berberis in various concentrations and temperatures (p<0.05). The difference between Berberis vulgaris juice and Berberis cratagina juice was lower. The reaction rate constant (k) increased and half-life (t1/2) decreased with increasing concentration of hydrogen peroxide in all juices. The temperature dependence of anthocyanins degradation was determined by calculating the activation energy (Ea) and temperature quotient (Q10). At the concentration of 10-20 mmol/L, Berberis vulgaris juice showed the lowest temperature dependence, whereas at higher concentrations (25 and 30 mmol/L) Beberis integerrima juice had the lowest temperature dependence. Conclusion: Anthocyanins from berberis species juices were found to be very susceptible to H2O2. Therefore, aseptic systems should be frequently controlled to ensure the effective removal of residual H2O2 from the food contact surfaces. Since the rate of anthocyanin degradation by H2O2 is highly dependent on temperature, cold storage of these juices is strongly recommended. Manuscript profile
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  2 - Effect of Aerobic and Anaerobic Composting on the Removal of Antibiotics of Enrofloxacin and Ciprofloxacin in Broiler Chicken Manure
  mahsa mohammadzadeh forouzan Ghasemian Roudsari Akbar Hassani Abbasali Zamani
  10.22034/jest.2020.35812.4264
  Background and Objective: Many of the antibiotics used in poultry farms are excreted in their feces. This waste is used as organic fertilizer in agriculture and causes the release of animal antibiotics in the environment. These compounds may increase the antibiotic resi More

  Background and Objective: Many of the antibiotics used in poultry farms are excreted in their feces. This waste is used as organic fertilizer in agriculture and causes the release of animal antibiotics in the environment. These compounds may increase the antibiotic resistance of microbial populations or damage plants grown in these soils. The aim of this study was to determine the effect of aerobic and anaerobic poultry manure composting on the amount of enrofloxacin and ciprofloxacin antibiotics in poultry manure at two levels of high and low concentration and compare them with each other. Method: Two samples of fresh broiler chicken manure were prepared after the end of the chicken treatment with antibiotic enrofloxacin. The two samples contained two levels of high and low concentrations of Enrofloxacin and Ciprofloxacin. The composting of chicken manure was done using a completely randomized design with 4 treatments of 1- aerobic treatments at a low concentration,              2- aerobic treatments at high concentration 3- anaerobic treatments at low concentration 4- anaerobic treatments at a high concentration in five replicates in 75 days. Samples were prepared at specific intervals and the concentration of Enrofloxacin and Ciprofloxacin was measured by HPLC method. The obtained data were fitted with the first-order kinetic equation and the half-life of the antibiotic degradation was calculated. Findings: The results showed that at the end of the period, in treatments 1 to 4, 54.2%, 64.3%, 65.3% and 69.7% of the Enrofloxacin and 41%, 57.8%, 57.8% and 61.8% Ciprofloxacin remained. The correlation coefficient (R2) obtained from the fitting of the first-order kinetic equation in treatments (from 0.71 to 0.92) showed that the data fit well with this equation. The half-life of the Enrofloxacin degradation was obtained between 96.27 and about 150.68 days. The half-life of degradation for Ciprofloxacin was also found to be between 57.28 and 117.48 days. Discussion and Conclusion: Overall, the results showed that the process of composting reduced the concentration of antibiotics and prevented its entry into the environment. The rate and total amount of antibiotic degradation in aerobic conditions was higher than anaerobic. The rate of degradation of both antibiotics at a high initial concentration was lower than its rate of degradation at low concentrations. The rate of ciprofloxacin degradation was also higher than Enrofloxacin. The results of this study can help to create relevant laws and regulations in relevant institutions, in order to reduce the release of veterinary antibiotics into the environment. Manuscript profile
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  3 - بهبود ارزش تغذیه‌ای کنجاله آفتاب‌گردان به ‌وسیله پرتوتابی با تابش الکترون و اشعه گاما
  F. Ghanbari T. Ghoorchi P. Shawrang H. Mansouri N.M. Torbati-Nejad
  این پژوهش به ­منظور مقایسه تأثیر تیمارهای پرتو الکترون و اشعه گاما در دزهای 25، 50 و 75 کیلوگری، بر کینتیک تجزیه شکمبه­ای و قابلیت هضم برون تنی کنجاله آفتاب­گردان انجام گرفت. پرتوهای یون­ساز الکترون و گاما اثر معنی‌داری بر فراسنجه­های تجزیه‌ پذیری ما More

  این پژوهش به ­منظور مقایسه تأثیر تیمارهای پرتو الکترون و اشعه گاما در دزهای 25، 50 و 75 کیلوگری، بر کینتیک تجزیه شکمبه­ای و قابلیت هضم برون تنی کنجاله آفتاب­گردان انجام گرفت. پرتوهای یون­ساز الکترون و گاما اثر معنی‌داری بر فراسنجه­های تجزیه‌ پذیری ماده خشک، پروتئین خام و اسیدهای آمینه کنجاله آفتاب­گردان داشتند (05/0P<). تجزیه پذیری مؤثر شکمبه­ای ماده خشک در کنجاله آفتاب­گردان پرتوتابی شده با تابش الکترون و اشعه گاما، کمتر از کنجاله آفتاب­گردان پرتوتابی نشده بود (05/0P<). تیمار پرتو گاما در دز 75 کیلوگری، تجزیه پذیری مؤثر شکمبه­ای پروتئین خام را در مقایسه با شاهد کاهش داد (05/0P<). تجزیه پذیری مؤثر شکمبه­ای پروتئین خام به ­وسیله تابش الکترون تحت تأثیر قرار نگرفت (05/0P>). عمل­آوری پرتوتابی باعث کاهش تجزیه اسیدهای آمینه بعد از 16 ساعت انکوباسیون شکمبه­ای شد (05/0P<). تأثیر پرتو گاما در کاهش تجزیه پذیری شکمبه­ای اسیدهای آمینه بیشتر از تابش الکترون بود (05/0P<). قابلیت هضم برون­تنی پروتئین خام در کنجاله آفتاب عمل­آوری شده با تابش الکترون و اشعه گاما بهبود یافت (05/0P<). این پژوهش، بر پایه مطالعات برون­تنی و تکنیک کیسه­های نایلونی، نشان داد که عمل­آوری با تابش الکترون و اشعه گاما می­تواند به ­عنوان یک روش مؤثر برای بهبود ارزش تغذیه­ای کنجاله آفتاب‌گردان مورد استفاده قرار گیرد. Manuscript profile
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  4 - Thermodegradation kinetics of poly(methyl methacrylate)/silver nanocomposites synthesized via in- situ photoiniferter-mediated photopolymerization
  پویان مکوندی ناصر نیکفرجام رضوان جمال الدین طاهر نادری قزوینی
  Here, we report thermodegradation of poly)methyl methacrylate(/silver nanoparticle )PMMA/AgNP( nanocomposite networks synthesized by in-situ photoiniferter-mediated photopolymerization. The nanocomposite networks were prepared in the presence of 0.5 wt.%of AgNP and vari More

  Here, we report thermodegradation of poly)methyl methacrylate(/silver nanoparticle )PMMA/AgNP( nanocomposite networks synthesized by in-situ photoiniferter-mediated photopolymerization. The nanocomposite networks were prepared in the presence of 0.5 wt.%of AgNP and various amounts of allyl methacrylate )0, 1, 5, 10 wt.%( as crosslinking agent. The kinetic studies of thermodegradation of the nanocomposite networks by two isoconversional methods, Flynn-Wall-Ozawa and Kissinger–Akahira–Sunose, showed that AgNP had a dual effect on thermal degradation of PMMA networks; at early stages, AgNP promoted the degradation of the nanocomposites while in the subsequent stages maintained the polymer stability against thermal degradation. Manuscript profile