scholarly journals THERMAL DEGRADATION KINETICS OF KAEMPFEROL AND QUERCETIN IN THE PRE-FORMULATED OF THE STANDARDIZED EXTRACTS OF POINCIANELLA PYRAMIDALIS (TUL.) L. P. QUEIROZ OBTAINED BY SPRAY DRYER

2017 ◽  
Vol 9 (6) ◽  
pp. 123 ◽  
Author(s):  
Agna HÉlia De Oliveira ◽  
Renata Da Silva Leite ◽  
FabrÍcio Havy Dantas ◽  
Valmir Gomes De Souza ◽  
JosÉ VenÂncio Chaves JÚnior ◽  
...  
Keyword(s):  
Degradation Kinetics ◽  
Processing Parameters ◽  
Thermal Degradation Kinetics ◽  
Response Analysis ◽  
Order Kinetic ◽  
Spray Dryer ◽  
Independent Variables ◽  
Significant Difference ◽  
Order Kinetic Model ◽  
The Stability

Objective: The aim of this work was to evaluate the stability and determine the kinetic parameters of degradation of biomarkers kaempferol and quercetin, present in the pre-formulated of the extract of Poincianella pyramidalis obtained by a spray dryer.Methods: A 23experimental design coupled with RSM was applied to evaluate and optimize the effects of processing parameters on the content of chemical markers in dry extracts by a spray dryer. Stability testing was performed to verify the influence of temperature on the degradation of kaempferol and quercetin present in the pre-formulated. The markers contents were determined by HPLC.Results: Surface response analysis showed the influence of the independent variables on the responses of the concentration kaempferol and quercentin biomarkers on the process. The variables of the inlet air temperature, flow feed rate and the adjuvant ratio presented negative responses with significant difference (p<0.05). According to the data obtained in the stability of the pre-formulated studied zero and second orders kinetics models the for degradation of the kaempferol and only second order kinetic model for the quercetin. It was also evaluated reducing the concentration of both biomarkers studied throughout the study.Conclusion: In the present study, it was observed that all independent variables of the drying process by spray dryer showed the greatest influence on the concentration of the studied markers. Two markers had a different thermal behavior compared to the different excipients studied and there was degradation of both the quercentin biomarker and kaempferol during the study period.

scholarly journals Thermo-Analytical and Compatibility Study with Mechanistic Explanation of Degradation Kinetics of Ambroxol Hydrochloride Tablets under Non-Isothermal Conditions

Pharmaceutics ◽  
2021 ◽  
Vol 13 (11) ◽  
pp. 1910
Author(s):  
Dijana Jelić ◽  
Snežana Papović ◽  
Milan Vraneš ◽  
Slobodan Gadžurić ◽  
Silvia Berto ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Active Compound ◽  
Degradation Kinetics ◽  
Practical Interest ◽  
Mechanistic Explanation ◽  
Compatibility Study ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Synthetic Derivative ◽  
Ambroxol Hydrochloride

Ambroxol hydrochloride (AMB), used as a broncho secretolytic and an expectorant drug, is a semi-synthetic derivative of vasicine obtained from the Indian shrub Adhatoda vasica. It is a metabolic product of bromhexine. The paper provides comprehensive and detailed research on ambroxol hydrochloride, gives information on thermal stability, the mechanism of AMB degradation, and data of practical interest for optimization of formulation that contains AMB as an active compound. Investigation on pure AMB and in commercial formulation Flavamed® tablet (FT), which contains AMB as an active compound, was performed systematically using thermal and spectroscopic methods, along with a sophisticated and practical statistical approach. AMB proved to be a heat-stable and humidity-sensitive drug. For its successful formulation, special attention should be addressed to excipients since it was found that polyvinyl pyrrolidone and Mg stearate affect the thermal stability of AMB. At the same time, lactose monohydrate contributes to faster degradation of AMB and change in decomposition mechanism. It was found that the n-th order kinetic model mechanistically best describes the decomposition process of pure AMB and in Flavamed® tablets.

scholarly journals Efecto del proceso de acidificación sobre el color de queso cottage

2017 ◽  
Vol 28 (3) ◽  
pp. 677 ◽  
Author(s):  
Ramiro Vargas-Uscategui ◽  
Anthony Arenas-Clavijo ◽  
Juan Sebastian Ramírez-Navas
Keyword(s):  
Linear Correlation ◽  
Color Change ◽  
Correlation Coefficients ◽  
Cottage Cheese ◽  
Order Kinetic ◽  
First Order ◽  
Zero Order Kinetics ◽  
Significant Difference ◽  
Order Kinetic Model ◽  
Kinetics Order

The objective of this study was to evaluate the color change of cottage cheese made with different processes of acidification (enzymatic and chemical) over time. The research was conducted at Universidad del Valle (Cali, Colombia) laboratories, between 2014 and 2015. Microbial rennet and lactic culture (CC) were used for enzymatic coagulation method (control cheese), and solutions of citric acid (CA) and phosphoric acid (PA) were used for the chemical method. The physicochemical properties were determined, and color behavior was analyzed over nine days of storage. Significant differences in acidity and moisture for the three coagulants were found. In the color plane, it was observed that the final and initial points of the coordinates a * and b * are close together; changes in color were mostly due to changes in brightness. The speed at which brightness decreased in the three cheeses matches kinetics order to zero and one. The first order kinetics displayed in higher values of linear correlation coefficients (R), AC: 0.8410 ± 0.0533; AF: 0.8390 ± 0.0847, and CC: 0.8717 ± 0.0256. The kinetics of change in color also adjusted correctly to zero and the first order kinetic model; that is, no significant difference (p <0.05) between these results. However, the speed of color change for the three cheeses had a slightly higher setting for zero order kinetics, as evidenced by the linear correlation coefficient (R) results, AC: 0.8800 ± 0.0205; AF: 0.8543 ± 0.0099, and CC: 0.7982 ± 0.0605.

scholarly journals Thermal Stability and Degradation Kinetics of Patulin in Highly Acidic Conditions: Impact of Cysteine

Toxins ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 662
Author(s):  
Enjie Diao ◽  
Kun Ma ◽  
Hui Zhang ◽  
Peng Xie ◽  
Shiquan Qian ◽  
...  
Keyword(s):  
Thermal Stability ◽  
Degradation Kinetics ◽  
Correlation Coefficients ◽  
Degradation Process ◽  
Weibull Model ◽  
Degradation Efficiency ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
Acidic Conditions ◽  
Kinetics Of

The thermal stability and degradation kinetics of patulin (PAT, 10 μmol/L) in pH 3.5 of phosphoric-citric acid buffer solutions in the absence and presence of cysteine (CYS, 30 μmol/L) were investigated at temperatures ranging from 90 to 150 °C. The zero-, first-, and second-order models and the Weibull model were used to fit the degradation process of patulin. Both the first-order kinetic model and Weibull model better described the degradation of patulin in the presence of cysteine while it was complexed to simulate them in the absence of cysteine with various models at different temperatures based on the correlation coefficients (R2 > 0.90). At the same reaction time, cysteine and temperature significantly affected the degradation efficiency of patulin in highly acidic conditions (p < 0.01). The rate constants (kT) for patulin degradation with cysteine (0.0036–0.3200 μg/L·min) were far more than those of treatments without cysteine (0.0012–0.1614 μg/L·min), and the activation energy (Ea = 43.89 kJ/mol) was far less than that of treatment without cysteine (61.74 kJ/mol). Increasing temperature could obviously improve the degradation efficiency of patulin, regardless of the presence of cysteine. Thus, both cysteine and high temperature decreased the stability of patulin in highly acidic conditions and improved its degradation efficiency, which could be applied to guide the detoxification of patulin by cysteine in the juice processing industry.

scholarly journals Thermal Degradation Kinetics of Anthocyanins Extracted from Purple Maize Flour Extract and the Effect of Heating on Selected Biological Functionality

Foods ◽  
2020 ◽  
Vol 9 (11) ◽  
pp. 1593
Author(s):  
Mioara Slavu (Ursu) ◽  
Iuliana Aprodu ◽  
Ștefania Adelina Milea ◽  
Elena Enachi ◽  
Gabriela Râpeanu ◽  
...  
Keyword(s):  
Antioxidant Activity ◽  
Thermal Degradation ◽  
Degradation Kinetics ◽  
In Vitro Release ◽  
Conformational Space ◽  
Thermal Degradation Kinetics ◽  
Order Kinetic ◽  
Preliminary Heating ◽  
Self Association

The thermal degradation of the anthocyanins and antioxidant activity in purple maize extracts was determined between 80 and 180 °C. The anthocyanins were found to be thermostable in the temperature range of 80 to 120 °C, whereas at higher temperatures the thermal degradation of both anthocyanins and antioxidant activity followed a first-order kinetic model. The z-values started from 61.72 ± 2.28 °C for anthocyanins and 75.75 ± 2.87 °C for antioxidant activity. The conformational space of pairs of model anthocyanin molecules at 25 and 180 °C was explored through a molecular dynamics test, and results indicated the occurrence of intermolecular self-association reactions and intramolecular co-pigmentation events, which might help explaining the findings of the degradation kinetics. The relationship between thermal degradation of anthocyanins and antioxidant activity and the in vitro release was further studied. The unheated extracts showed a high stability under gastric environment, whereas after heating at 180 °C, the digestion ended quickly after 60 min. After simulated intestinal digestion, the anthocyanins were slowly decreased to a maximum of 12% for the unheated extracts, whereas an 83% decrease was found after preliminary heating at 180 °C. The thermal degradation of anthocyanins was positively correlated with the in vitro decrease of antioxidant activity.

Anaerobic degradation kinetics of a cholesteryl ester

2003 ◽  
Vol 48 (6) ◽  
pp. 141-147
Author(s):  
S. Gutiérrez ◽  
M. Viñas
Keyword(s):  
Palmitic Acid ◽  
Anaerobic Degradation ◽  
Drop Size ◽  
Degradation Kinetics ◽  
Relative Rate ◽  
Hydrolysis Rate ◽  
Order Kinetic ◽  
Order Kinetic Model ◽  
The Difference ◽  
Kinetics Of

The most important components of wool scouring effluent grease are esters of sterols. Cholesteryl palmitate (CP) is the main ester in this grease. In this paper, the influence of the ester concentration in the anaerobic digestion and the relative rate of the different degradation steps, are studied. The experiment was carried out to measure methane production in the anaerobic degradation of acetate, palmitic acid (PA) and CP. A first-order kinetic model was assumed for hydrolysis and Monod models were assumed for both the methanogenic and acetogenic steps. Maximum hydrolysis rate was found to be around 20 times faster than the maximum methanogenic reaction rate during the experience. The lanolin emulsion drop size effect was also evaluated employing fine and coarse stock lanolin emulsions and no adapted sludge. Concentrations of 13.7 to 4.6 gCOD.l-1 were employed. In a previous study, the effect of palmitic acid emulsion size was found important when similar sludge was tested. When esters are degraded, a significant effect of drop size on the degradation rate was not found. The difference between CP and PA emulsions behavior could be due to the fact that cholesterol produced during the ester degradation has a protective effect on the sludge.

Sorption of cesium on Tamusu clay in synthetic groundwater with high ionic strength

2020 ◽  
Vol 108 (4) ◽  
pp. 287-296
Author(s):  
Han Zhang ◽  
Yang Dong ◽  
Hanyi He ◽  
Honghui Li ◽  
Shuaiwei Zhao ◽  
...  
Keyword(s):  
Exchange Process ◽  
Freundlich Isotherm ◽  
Deionized Water ◽  
Order Kinetic ◽  
Sorption Behaviour ◽  
Ion Exchange Process ◽  
Significant Difference ◽  
Initial Ph ◽  
Order Kinetic Model ◽  
Synthetic Groundwater

AbstractThe sorption behaviour of cesium on Tamusu clay was first investigated by batch experiments under synthetic groundwater and deionized water conditions. The results showed that the sorption could be well described by the pseud-second-order kinetic model or by the Freundlich isotherm model, and the Kd values decreased rapidly when temperature was greater than 328 K. However, the influence of initial cesium concentration, initial pH and Humic acid (HA) on the sorption behaviour in the synthetic groundwater exhibited a significant difference from those in the deionized water. In particular, the Kd value in the synthetic groundwater (5.47 mL/g) was much lower than that in the deionized water (58.97 mL/g). The SEM/EDS, effect of ion strength and pH-independent results in the synthetic groundwater indicated the cesium sorption on Tamusu clay was mainly involved in an ion exchange process. Additionally, the research reported in this work implies that the retardation of cesium on Tamusu clay was significantly lower than that on other clay rock in the world. The results suggest that the sorption behaviour of cesium or other nuclides on Tamusu clay should be evaluated in synthetic or actual groundwater but not in deionized water.

scholarly journals Thermomechanical and Morphological Studies of CFRP Tested in Different Environmental Conditions

Materials ◽  
2018 ◽  
Vol 12 (1) ◽  
pp. 63 ◽  
Author(s):  
Claudia Barile ◽  
Caterina Casavola ◽  
Paramsamy Vimalathithan ◽  
Marco Pugliese ◽  
Vincenzo Maiorano
Keyword(s):  
Activation Energy ◽  
Thermal Degradation ◽  
Mass Loss ◽  
Environmental Conditions ◽  
Degradation Kinetics ◽  
Fiber Reinforced Polymers ◽  
Thermal Degradation Kinetics ◽  
Morphological Studies ◽  
Significant Difference ◽  
Kinetics Of

The present work describes the mechanical characterization combined with the thermal degradation kinetics of Carbon Fiber Reinforced Polymers (CFRP). The thermal degradation kinetics of CFRP have never been studied in the past. In that regard, the present work focuses on studying the thermal degradation kinetics of CFRP tested mechanically at different environmental conditions. Tensile tests were performed on the specimens with different lay-ups at room temperature, elevated temperature (71 °C), and cryogenic conditions (−54 °C), and the same specimens were used for thermal degradation kinetic studies. Mechanical tests show different responses respect to the different environmental conditions and different fibers orientation. On the other hand, the thermogravimetric results, mass loss, and derivative mass loss, show no significant difference in the degradation of CFRP tested at different temperatures. However, the thermal degradation kinetics shows more insight into the degradation pattern of the materials. The activation energy of degradation shows that the degradation of materials subjected to elevated conditions increases rapidly in the later stages of degradation, suggesting the formation of high char yield. The varying activation energy has been related to different degradation mechanisms. Lastly, the morphology of the materials was studied under SEM to understand the structural change in the material after tested in different weather conditions.

Adsorption of azo dyes from aqueous solution by the hybrid MOFs/GO

2016 ◽  
Vol 73 (7) ◽  
pp. 1728-1737 ◽  
Author(s):  
Ling Li ◽  
Zhennan Shi ◽  
Hongyang Zhu ◽  
Wei Hong ◽  
Fengwei Xie ◽  
...  
Keyword(s):  
Aqueous Solution ◽  
Azo Dyes ◽  
Metal Organic Framework ◽  
Freundlich Isotherm ◽  
Order Kinetic ◽  
Sunset Yellow ◽  
Order Kinetic Model ◽  
Metal Organic ◽  
Pseudo Second Order ◽  
The Stability

In this work, a hybrid of chromium(III) terephthalate metal organic framework (MIL-101) and graphene oxide (GO) was synthesized and its performance in the removal of azo dyes (Amaranth, Sunset Yellow, and Carmine) from water was evaluated. The adsorption for azo dyes on MIL-101/GO was compared with that of MIL-101, and it was found that the addition of GO enhanced the stability of MIL-101 in water and increased the adsorption capacity. The maximum adsorption capacities of MIL-101/GO were 111.01 mg g−1 for Amaranth, 81.28 mg g−1 for Sunset Yellow, and 77.61 mg g−1 for Carmine. The adsorption isotherms and kinetics were investigated, showing that the adsorption fits the Freundlich isotherm and the pseudo-second-order kinetic model. The recyclability of MIL-101/GO was shown by the regeneration by acetone. The high adsorption capability and excellent reusability make MIL-101/GO a competent adsorbent for the removal dyes from aqueous solution.

scholarly journals Effect of Bio-Based Surfactant on Wettability of Low-Rank Coal Surface and Its Mechanism

2021 ◽  
Author(s):  
Lin Li ◽  
Mingpu Liu ◽  
Jianqiao Lvu ◽  
Xiaoteng Li ◽  
Zhihao Li ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Water System ◽  
Low Rank ◽  
Order Kinetic ◽  
Low Rank Coal ◽  
Adsorption Model ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
The Stability ◽  
Adhesion Work

Abstract In this study, the effect of a bio-based environment-friendly surfactant, cardanol polyoxyethylene ether (BGF), on the wettability of the surface of low-rank coal (LRC) and its mechanism were studied. The adsorption experiment showed that the adsorption of the surfactant conformed to the Langmuir adsorption model and the pseudo-second-order kinetic model. The adsorption was mainly affected by hydrogen bonding, and the adsorption rate was affected by intraparticle diffusion and liquid film diffusion. The wettability experiment showed that the influence of BGF on the wettability of the surface of LRC followed the given order: BGF-7 > BGF-10 > BGF-15. The investigation of adhesion work showed that the adhesion work and the stability of the coal–water system decreased after adsorption. Fourier transform infrared and X-ray photoelectron spectroscopy analyses showed that after adsorption, the peak strength of vinyl ether, the content of elemental carbon, and the content of C-C/C-H groups increased.

scholarly journals Modification of Silica Coated on Iron Sand Magnetic Material with Chitosan for Adsorption of Au(III)

2017 ◽  
Vol 17 (2) ◽  
pp. 264 ◽  
Author(s):  
Muflikhah Muflikhah ◽  
Bambang Rusdiarso ◽  
Edy Giri Rachman Putra ◽  
Nuryono Nuryono
Keyword(s):  
Magnetic Material ◽  
Sol Gel ◽  
Order Kinetic ◽  
External Magnet ◽  
X Ray ◽  
Sol Gel Process ◽  
Order Kinetic Model ◽  
Pseudo Second Order ◽  
Ft Ir ◽  
The Stability

Modification of silica coated on magnetic material iron sand with chitosan for adsorption of Au(III) has been carried out. Magnetic material (MM) from iron sand was separated using an external magnet, washed with water and HF solution 10%. MM–silica–chitosan material (MMSC) was synthesized via sol gel process and the product was characterized with Fourier Transform Infrared (FT-IR) spectrophotometer, X–ray diffractometer, scanning electron microscopy and energy dispersive X–ray, thermogravimetric analysis, and vibration sample magnetometer. Additionally, the effect of pH on the stability of MMSC has also been tested. The adsorption of Au(III) on MMSC was proceeded in a batch system with variation of pH, contact time, and concentration of absorbate. Adsorbent was separated using external magnet and concentration of Au(III) not adsorbed was analyzed using Atomic Absorption Spectrometer. Characterization result indicated that MMSC was successfully synthesized. Adsorption of Au(III) on MMSC followed pseudo second-order kinetic model with the value of adsorption rate constant (k) of 4.10 x 10-3 g mg-1 min-1 and adsorption isotherm fixed with Langmuir model with the adsorption capacity (qmax) of 149.25 mg g-1.

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