Modelling the Kinetics of Color and Texture Changes of Dabai (Canarium odontophyllum Miq.) during Blanching

Dabai (Canarium odontophyllum Miq.) is a fruit that is often eaten by first blanching in hot water to make the flesh creamier and softer, before it is served as a snack or side dish. In this study, Dabai fruit was blanched at different temperatures between 60 and 100 °C, with an increment of 10 °C, for up to 10 min, and the kinetics of quality changes (color and texture) were studied. Kinetic models that were assessed for changes of color and texture were zero-order, first-order, and fractional conversion model. The results showed that L parameter had no change throughout the blanching process, while parameters a*, b*, chroma (C), and total color difference (TCD) resulted as significantly increased as the temperature and duration of blanching increased. However, the change of firmness was not significant due to minor changes of firmness as the temperature and time increased. In terms of kinetic models, zero and fractional-conversion order well described the changes of a* parameter; while zero, first and fractional conversion well described parameters b*, C and TCD. Change of firmness did not fit with zero or first-order. All of the kinetic models obeyed the Arrhenius equation. Thus, the fitted kinetic models can be used to design the blanching process of Dabai fruit.

Download Full-text

Kinetics of Quality Attributes of Potato Particulates during Cooking Process

International Journal of Food Engineering ◽

10.1515/ijfe-2014-0341 ◽

2016 ◽

Vol 12 (1) ◽

pp. 27-35 ◽

Cited By ~ 2

Author(s):

B. Jobe ◽

N.S. Rattan ◽

H.S. Ramaswamy

Keyword(s):

Ascorbic Acid ◽

Temperature Dependence ◽

Testing Machine ◽

Quality Attributes ◽

Time Range ◽

Fractional Conversion ◽

Order Model ◽

Conversion Model ◽

First Order ◽

Kinetics Of

Abstract Kinetics of thermal texture softening, color change and loss of ascorbic acid in potato (Solanum tuberosum) were investigated at selected temperature range (70–100°C) and heating time range (0–50 min). Cut samples of potatoes were heated in a constant temperature water bath at various temperatures. Heat-treated samples were evaluated for texture, color and ascorbic acid by use of a texture-testing machine, a color meter and spectrophotometer, respectively. The biphasic first-order model, the fractional conversion model and the simple first-order model were used for fitting experimental data of time dependence kinetics, while the simple first-order model and Arrhenius model were used for temperature dependence kinetics. The results indicated that the biphasic first-order model can match well to the texture softening of potato samples, the fractional conversion model can well describe the kinetics of color, and the simple first-order model can be used for the kinetics of ascorbic acid. The kinetic parameters including decimal deduction time (D), reaction rate (k), temperature dependence (z) and activation energy (Ea) were determined by the nonlinear regression method. The correlation matrix between quality attributes including texture properties, color and ascorbic acid loss was developed based on the kinetic models. The results obtained from this study were compared with those previously reported.

Download Full-text

Kinetics of Phenolic Compounds Modification during Maize Flour Fermentation

Molecules ◽

10.3390/molecules26216702 ◽

2021 ◽

Vol 26 (21) ◽

pp. 6702

Author(s):

Oluwafemi Ayodeji Adebo ◽

Ajibola Bamikole Oyedeji ◽

Janet Adeyinka Adebiyi ◽

Chiemela Enyinnaya Chinma ◽

Samson Adeoye Oyeyinka ◽

...

Keyword(s):

Phenolic Compounds ◽

Phenolic Acids ◽

Kinetic Models ◽

Titratable Acidity ◽

Second Order ◽

Soluble Solids ◽

Maize Flour ◽

First Order ◽

Compound Modification ◽

Kinetics Of

This study aimed to investigate the kinetics of phenolic compound modification during the fermentation of maize flour at different times. Maize was spontaneously fermented into sourdough at varying times (24, 48, 72, 96, and 120 h) and, at each point, the pH, titratable acidity (TTA), total soluble solids (TSS), phenolic compounds (flavonoids such as apigenin, kaempferol, luteolin, quercetin, and taxifolin) and phenolic acids (caffeic, gallic, ferulic, p-coumaric, sinapic, and vanillic acids) were investigated. Three kinetic models (zero-, first-, and second-order equations) were used to determine the kinetics of phenolic modification during the fermentation. Results obtained showed that fermentation significantly reduced pH, with a corresponding increase in TTA and TSS. All the investigated flavonoids were significantly reduced after fermentation, while phenolic acids gradually increased during fermentation. Among the kinetic models adopted, first-order (R2 = 0.45–0.96) and zero-order (R2 = 0.20–0.82) equations best described the time-dependent modifications of free and bound flavonoids, respectively. On the other hand, first-order (R2 = 0.46–0.69) and second-order (R2 = 0.005–0.28) equations were best suited to explain the degradation of bound and free phenolic acids, respectively. This study shows that the modification of phenolic compounds during fermentation is compound-specific and that their rates of change may be largely dependent on their forms of existence in the fermented products.

Download Full-text

Reactivity of Phenol and Aniline towards Quinolinium Chloro Chromate: A Comparative Oxidation Kinetic Study

International Letters of Chemistry Physics and Astronomy ◽

10.18052/www.scipress.com/ilcpa.59.81 ◽

2015 ◽

Vol 59 ◽

pp. 81-92

Author(s):

Seplapatty Kalimuthu Periyasamy ◽

H. Satham Hussain ◽

R. Manikandan

Keyword(s):

Oxidation Kinetic ◽

Activation Parameters ◽

Dipole Interaction ◽

Reaction Rates ◽

Hydrogen Ion ◽

Aqueous Acetic Acid ◽

Acetic Acid Medium ◽

First Order ◽

Different Temperatures ◽

Kinetics Of

The kinetics of Oxidation of Phenol and aniline by quinolinium Chlorochromate (QCC) in aqueous acetic acid medium leads to the formation of quinone and azobenzene respectively. The reactions are first order with respect to both Phenol and aniline. The reaction is first order with respect to quinolinium chlorochromate (QCC) and is catalyzed by hydrogen ion. The hydrogen-ion dependence has the form: kobs = a+b [H+]. The rate of oxidation decreases with increasing dielectric constant of solvent, indicating the presence of an ion-dipole interaction. The reaction does not induced the polymerization of acrylonitrile. The retardation of the rate by the addition of Mn2+ ions confirms that a two electron transfer process is involved in the reaction. The reaction rates have been determined at different temperatures and the activation parameters have been calculated. From the above observations kinetic results a probable mechanism have been proposed.

Download Full-text

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.

Download Full-text

Reactivity and kinetic studies of benzofuran hydrodeoxygenation over a Ni2P-O/MCM-41 catalyst

Progress in Reaction Kinetics and Mechanism ◽

10.1177/1468678319825909 ◽

2019 ◽

Vol 44 (4) ◽

pp. 307-315 ◽

Cited By ~ 1

Author(s):

Xueya Dai ◽

Hua Song ◽

Hualin Song ◽

Jing Gong ◽

Feng Li ◽

...

Keyword(s):

Kinetic Studies ◽

Time Analysis ◽

Liquid Ratio ◽

Order Model ◽

Free Products ◽

First Order ◽

Reaction Rate Constants ◽

Different Temperatures ◽

Kinetics Of ◽

Mcm 41

A nickel phosphide hydrodeoxygenation catalyst (Ni2P-O/MCM-41) was prepared using a new synthetic method. The as-prepared catalyst was evaluated in the hydrodeoxygenation of benzofuran, and the effects of reaction temperature, pressure, and the H2/liquid ratio were investigated. A pseudo first-order model was employed to describe the reaction kinetics of benzofuran hydrodeoxygenation over the Ni2P-O/MCM-41 catalyst. The reaction rate constants ( k1– k5) at different temperatures were determined according to this model. At 533 K, the conversion of 2-ethylphenol in to ethylbenzene began to increase dramatically, and the yield of O-free product, ethylcyclohexane, started to increase rapidly. At 573 K, 3.0 MPa, and a H2/liquid ratio of 500 (V/V), the conversion of benzofuran over Ni2P-O/MCM-41 reached 93%, and the combined yield of O-free products was 91%. Contact time analysis indicated that demethylation was not favored over the Ni2P-O/MCM-41 catalyst.

Download Full-text

Kinetics of the Substitution of Norbornadiene in Tetracarbonyl(norbomadiene)molybdenum(0) by 2,2'-Bipyridine

Zeitschrift für Naturforschung B ◽

10.1515/znb-2001-0310 ◽

2001 ◽

Vol 56 (3) ◽

pp. 281-286 ◽

Cited By ~ 5

Author(s):

Ceyhan Kayran ◽

Eser Okan

Keyword(s):

Reaction Rate ◽

Activation Parameters ◽

Bipy Ligand ◽

First Order ◽

Rate Determining Step ◽

Vis Spectroscopy ◽

Different Temperatures ◽

Ft Ir ◽

Thermal Substitution ◽

Kinetics Of

Abstract The kinetics of the thermal substitution of norbornadiene (nbd) by 2,2'-bipyridine (2,2'-bipy) in (CO)4Mo(C7H9) was studied by quantitative FT-IR and UV-VIS spectroscopy. The reaction rate exhibits first-order dependence on the concentration of the starting complex, and the observed rate constant depends on the concentration of both leaving nbd and entering 2,2'-bipy ligand. The mechanism was found to be consistent with the previously proposed one, where the rate determining step is the cleavage of one of the two Mo-olefin bonds. The reaction was performed at four different temperatures (35 -50 °C) and the evaluation of the kinetic data gives the activation parameters which now support states.

Download Full-text

Thermodynamics and kinetics of thermal deactivation of catalase Aspergillus niger

Polish Journal of Chemical Technology ◽

10.2478/pjct-2020-0018 ◽

2020 ◽

Vol 22 (2) ◽

pp. 67-72

Author(s):

Justyna Miłek

Keyword(s):

Aspergillus Niger ◽

Life Time ◽

Economic Feasibility ◽

Thermal Deactivation ◽

Order Model ◽

First Order ◽

Thermodynamics And Kinetics ◽

Different Temperatures ◽

Kinetics Of ◽

Thermal Stability Of

AbstractThe thermal stability of enzyme-based biosensors is crucial in economic feasibility. In this study, thermal deactivation profiles of catalase Aspergillus niger were obtained at different temperatures in the range of 35°C to 70°C. It has been shown that the thermal deactivation of catalase Aspergillus niger follows the first-order model. The half-life time t1/2 of catalase Aspergillus niger at pH 7.0 and the temperature of 35°C and 70°C were 197 h and 1.3 h respectively. Additionally, t1/2 of catalase Aspergillus niger at the temperature of 5°C was calculated 58 months. Thermodynamic parameters the change in enthalpy ΔH*, the change in entropy ΔS* and the change Gibbs free energy ΔG* for the deactivation of catalase at different temperatures in the range of 35°C to 70°C were estimated. Catalase Aspergillus niger is predisposed to be used in biosensors by thermodynamics parameters obtained.

Download Full-text

Kinetics and mechanism of aminolysis of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones

Canadian Journal of Chemistry ◽

10.1139/v92-318 ◽

1992 ◽

Vol 70 (10) ◽

pp. 2515-2519 ◽

Cited By ~ 3

Author(s):

Sharifa S. Alkaabi ◽

Ahmad S. Shawali

Keyword(s):

Rate Constants ◽

Activation Parameters ◽

Order Conditions ◽

Kinetics And Mechanism ◽

Hammett Equation ◽

Third Order ◽

First Order ◽

Different Temperatures ◽

Pseudo First Order ◽

Kinetics Of

The kinetics of the reactions of a series of (Z)-4-arylidene-2-phenyl-5(4H)oxazolones 1 with n-butylamine and piperidine were studied spectrophotometrically in dioxane, ethanol, and cyclohexane under pseudo-first-order conditions and at different temperatures. The relation k1(obs) = k2[amine] + k3[amine]2 was found applicable for all reactions studied in either dioxane or ethanol. However, in cyclohexane the n-butylaminolysis of 1 followed only third-order kinetics k1(obs) = k3[n-BuNH2]2. The kinetics of the reaction of 1 with n-butylamine in the presence of catalytic amounts of triethylamine in dioxane followed the equation: k1(obs)k2 = [n-BuNH2] + k3[n-BuNH2]2[Formula: see text] [Et3N]. The rate constants k2 and k3 correlated well with the Hammett equation and the corresponding activation parameters were determined. The results were interpreted in terms of a mechanism involving solvent- and amine-catalyzed processes.

Download Full-text

Thermodynamics of copper desorption from soils as affected by citrate and succinate

Soil and Water Research ◽

10.17221/2110-swr ◽

2008 ◽

Vol 2 (No. 4) ◽

pp. 135-140 ◽

Cited By ~ 1

Author(s):

E.A. Elkhatib ◽

A.M. Mahdy ◽

N.H. Barakat

Keyword(s):

Contaminated Soils ◽

Reaction Rate Constant ◽

Organic Ligands ◽

Order Kinetic ◽

First Order ◽

Dissolved Organics ◽

Different Temperatures ◽

Energy Consuming ◽

Delta G ◽

Kinetics Of

Desorption of Cu and low molecular weight dissolved organics are the primary factors that impact fate and transport of Cu in soils. To improve predictions of the toxicity and threat from Cu contaminated soil, it is critical that time-dependent desorption behaviour be understood. In this paper, the effect of organic ligands citrate and succinate on the kinetics of Cu desorption from contaminated soils varying widely in soil characteristics was investigated at three different temperatures. The results showed that the first order equation adequately described the kinetics of Cu desorption from clay and sandy soils under isothermal conditions. The reaction rate constant (k<sub>d</sub>) values of the first order kinetic equation for Cu desorption increased consistently with temperature, indicating faster release of Cu at higher temperatures. The Cu desorption rate from the studied soils at all three temperatures was as follows: citric > succinic. The E<sub>a</sub>values indicates that Cu desorption from the studied soils in the presence of two organic ligands is a diffusion controlled reaction. The negative values of ΔH* suggest that the desorption reactions are not energy consuming process. The higher negative values of (ΔH*) for Cu desorption from the studied soils in the presence of succinic ligand indicate that the heat energy required to overcome the Cu desorption barrier was greater than that for Cu desorption in the presence of citric ligand. Computation of the free energy of activation (ΔG*) yielded values ranging for 87 to 87.9 kJ/mol. The largest value represents ΔG* for Cu desorption for clay soil in the presence of succinic acid while the lowest value represents ΔG* for Cu desorption for sandy soil in the presence of citric acid. The information in this study is quite necessary to construct full functioning models that will help scientists to better understand mobility and bioavailability of metals in soils.

Download Full-text

Vulcanization of Elastomers. 36. Vulcanization of Natural Rubber and Synthetic Rubbers with Sulfur in Absence of Accelerators. II

Rubber Chemistry and Technology ◽

10.5254/1.3540389 ◽

1964 ◽

Vol 37 (4) ◽

pp. 910-926 ◽

Cited By ~ 1

Author(s):

W. Scheele ◽

H. Müller ◽

W. Schulze

Keyword(s):

Natural Rubber ◽

Concentration Dependence ◽

Good Description ◽

Kcal Mole ◽

First Order ◽

Different Temperatures ◽

In Cis ◽

Kinetics Of ◽

Limiting Value ◽

Homolytic Dissociation

Abstract In continuation of earlier work with natural rubber, the kinetics of sulfur decrease were studied in certain synthetic rubbers for different temperatures and sulfur concentrations. At the same time the formation of polysulfide bound sulfur was studied, using as example the reaction of sulfur with natural rubber and synthetic rubbers. It was found that: 1) When the decrease in sulfur concentration is portrayed by curves which are convex to the time axis (Perbunan), the 0.6th order time-law is fulfilled, (as in the case of natural rubber independent of temperature and concentration. 2) In contrast, the concentration dependence of the rate at which sulfur decreases, both in Perbunan and cis 1,4-polybutadiene, denotes a first-order reaction in agreement with experience with natural rubber. 3) The activation energy of sulfur decrease has the same magnitude for all the elastomers investigated (34 to 36 kcal/mole). 4) The disagreement between the time law and the concentration dependence of the rate of sulfur disappearance encountered in all the experiments with 1,5-polyenes, is interpreted as indicating autocatalysis, which likewise explains the shape of the curves for sulfur disappearance. 5) Sulfur reacts considerably faster in natural rubber and Perbunan than in cis 1,4-polybutadiene; consequently a homolytic dissociation of the S8-ring cannot be rate-determining. 6) Polysulfide sulfur shows, in each case, a maximum with reaction time, and in completely reacted vulcanizates it tends toward a limiting value. An equation was found, which provides a good description of change with time of polysulfide concentration (natural rubber and cis 1,4-polybutadiene). 7) An explanation is given for the appearance of the polysulfide maximum; and how the reaction of sulfur with 1,5-polyenes can be represented, making use of all available results, is discussed.

Download Full-text