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Salmah Yusof - One of the best experts on this subject based on the ideXlab platform.

  • Optimization of the contents of Arabic gum, xanthan gum and orange oil affecting turbidity, average particle size, Polydispersity Index and density in orange beverage emulsion
    Food Hydrocolloids, 2008
    Co-Authors: Hamed Mirhosseini, Nazimah Hamid, Salmah Yusof
    Abstract:

    This paper focuses on the development of an effective methodology to determine the optimum levels of three independent variables leading to (a) maximize turbidity, (b) minimize Polydispersity Index (PDI) and (c) obtain the target value for average particle size and density of orange beverage emulsion. A three-factor central composite design (CCD) was employed to determine the effect of Arabic gum content (7–13% w/w), xanthan gum content (0.1–0.3% w/w) and orange oil content (6–10% w/w). The emulsion properties studied as response variables were: turbidity (Y1), average particle size (Y2), PDI (Y3) and density (Y4). The response surface analysis was carried out to create efficient empirical models for predicting the changes of response variables. In general, analysis of variance (ANOVA) showed high coefficients of determination values (R2) in the range of 0.922–0.975 for the response surface models, thus ensuring a satisfactory adjustment of the polynomial regression models with the experimental data. The results of regression analysis indicated that more than 92% the response variation could be explained by the models. The results also indicated that the linear term of xanthan gum was the most significant (p

  • optimization of the contents of arabic gum xanthan gum and orange oil affecting turbidity average particle size Polydispersity Index and density in orange beverage emulsion
    Food Hydrocolloids, 2008
    Co-Authors: Hamed Mirhosseini, Nazimah Hamid, Salmah Yusof
    Abstract:

    This paper focuses on the development of an effective methodology to determine the optimum levels of three independent variables leading to (a) maximize turbidity, (b) minimize Polydispersity Index (PDI) and (c) obtain the target value for average particle size and density of orange beverage emulsion. A three-factor central composite design (CCD) was employed to determine the effect of Arabic gum content (7–13% w/w), xanthan gum content (0.1–0.3% w/w) and orange oil content (6–10% w/w). The emulsion properties studied as response variables were: turbidity (Y1), average particle size (Y2), PDI (Y3) and density (Y4). The response surface analysis was carried out to create efficient empirical models for predicting the changes of response variables. In general, analysis of variance (ANOVA) showed high coefficients of determination values (R2) in the range of 0.922–0.975 for the response surface models, thus ensuring a satisfactory adjustment of the polynomial regression models with the experimental data. The results of regression analysis indicated that more than 92% the response variation could be explained by the models. The results also indicated that the linear term of xanthan gum was the most significant (p<0.05) variable affecting the overall responses. The multiple optimization results showed that the overall optimum region with high total desirability (D=0.92) was found to be at the combined level of 13.88% w/w Arabic gum content, 0.27% w/w xanthan gum content and 11.27% w/w orange oil content. Under the optimum condition, the corresponding predicted response values for turbidity, average particle size, PDI and density of the desirable orange beverage emulsion were 129.55, 988, 0.261 and 1.03, respectively. For validation of the models, the experimental values were compared with predicted values to check the adequacy of the models. The experimental values were found to be in agreement with those predicted, thus indicating suitability of the models employed using response surface methodology (RSM) for optimizing the physical properties of the orange beverage emulsion.

Hamed Mirhosseini - One of the best experts on this subject based on the ideXlab platform.

  • Optimization of the contents of Arabic gum, xanthan gum and orange oil affecting turbidity, average particle size, Polydispersity Index and density in orange beverage emulsion
    Food Hydrocolloids, 2008
    Co-Authors: Hamed Mirhosseini, Nazimah Hamid, Salmah Yusof
    Abstract:

    This paper focuses on the development of an effective methodology to determine the optimum levels of three independent variables leading to (a) maximize turbidity, (b) minimize Polydispersity Index (PDI) and (c) obtain the target value for average particle size and density of orange beverage emulsion. A three-factor central composite design (CCD) was employed to determine the effect of Arabic gum content (7–13% w/w), xanthan gum content (0.1–0.3% w/w) and orange oil content (6–10% w/w). The emulsion properties studied as response variables were: turbidity (Y1), average particle size (Y2), PDI (Y3) and density (Y4). The response surface analysis was carried out to create efficient empirical models for predicting the changes of response variables. In general, analysis of variance (ANOVA) showed high coefficients of determination values (R2) in the range of 0.922–0.975 for the response surface models, thus ensuring a satisfactory adjustment of the polynomial regression models with the experimental data. The results of regression analysis indicated that more than 92% the response variation could be explained by the models. The results also indicated that the linear term of xanthan gum was the most significant (p

  • optimization of the contents of arabic gum xanthan gum and orange oil affecting turbidity average particle size Polydispersity Index and density in orange beverage emulsion
    Food Hydrocolloids, 2008
    Co-Authors: Hamed Mirhosseini, Nazimah Hamid, Salmah Yusof
    Abstract:

    This paper focuses on the development of an effective methodology to determine the optimum levels of three independent variables leading to (a) maximize turbidity, (b) minimize Polydispersity Index (PDI) and (c) obtain the target value for average particle size and density of orange beverage emulsion. A three-factor central composite design (CCD) was employed to determine the effect of Arabic gum content (7–13% w/w), xanthan gum content (0.1–0.3% w/w) and orange oil content (6–10% w/w). The emulsion properties studied as response variables were: turbidity (Y1), average particle size (Y2), PDI (Y3) and density (Y4). The response surface analysis was carried out to create efficient empirical models for predicting the changes of response variables. In general, analysis of variance (ANOVA) showed high coefficients of determination values (R2) in the range of 0.922–0.975 for the response surface models, thus ensuring a satisfactory adjustment of the polynomial regression models with the experimental data. The results of regression analysis indicated that more than 92% the response variation could be explained by the models. The results also indicated that the linear term of xanthan gum was the most significant (p<0.05) variable affecting the overall responses. The multiple optimization results showed that the overall optimum region with high total desirability (D=0.92) was found to be at the combined level of 13.88% w/w Arabic gum content, 0.27% w/w xanthan gum content and 11.27% w/w orange oil content. Under the optimum condition, the corresponding predicted response values for turbidity, average particle size, PDI and density of the desirable orange beverage emulsion were 129.55, 988, 0.261 and 1.03, respectively. For validation of the models, the experimental values were compared with predicted values to check the adequacy of the models. The experimental values were found to be in agreement with those predicted, thus indicating suitability of the models employed using response surface methodology (RSM) for optimizing the physical properties of the orange beverage emulsion.

Deyue Yan - One of the best experts on this subject based on the ideXlab platform.

  • Kinetic analysis of co-polycondensation of AB2 and AB type monomers in presence of multi-functional cores
    Polymer, 2010
    Co-Authors: Zhiping Zhou, Zhengwei Jia, Deyue Yan
    Abstract:

    Abstract This work theoretically deals with the kinetics of the co-polycondensation of AB 2 and AB type monomers in the presence of multi-functional cores. The analytical expressions of the molecular size distribution function and the molecular parameters of the resultant hyperbranched polymers were derived. The general expressions are applicable for the copolymerization of AB 2 and AB monomers and the polymerization of homogeneous AB 2 or AB monomers in either presence or absence of cores. The feed ratio of the core molecules ( β ) or the AB 2 monomers ( α ) to the total monomers significantly affects the molecular weight distribution and the molecular parameters of the products. The Polydispersity Index of the copolymerization of AB 2 and AB monomers without cores is infinite when the reaction approaches to completion, while the presence of core molecules makes it become finite. The Polydispersity Index decreases with decreasing α , which also decreases with increasing β . The higher the functionality of the core ( f ), the lower the Polydispersity Index is as well.

  • Kinetic model of living radical polymerization
    Macromolecular Theory and Simulations, 1996
    Co-Authors: Deyue Yan, Hong Jiang, Xunpei Fan
    Abstract:

    This work studies the kinetics of living radical polymerization by means of both the non-steady state approach and the quasi-stationary state method. Expressions for the number-and weight-average degrees of polymerization and the Polydispersity Index were derived. Numerical results show that the concentration of residual initiator seriously influences the Polydispersity Index of the resulting polymer. The calculated outcomes of the non-steady state approach are evidently different from those of the quasi-stationary state method when the magnitude of the rate constant of termination is comparable with that of the propagation rate constant, and the difference becomes negligible if the rate constant of the termination (k t ) is much larger than that of propagation (k P ). The Polydispersity Index of the resulting polymer increases with decreasing ratios of k t to k p or M 0 to I 0 (initial concentrations of monomer and initiator).

  • Kinetic Analysis of “Living” Polymerization Processes Exhibiting Slow Equilibria. 5.† Effect of Monomer Transfer in Cationic Polymerization and Similar Living Processes†
    Macromolecules, 1996
    Co-Authors: Deyue Yan, Hong Jiang, Hai Dong, Axel H. E. Müller
    Abstract:

    This work deals with the kinetics of polymerization processes with chain transfer to monomer and reversible formation of dormant species. Such a mechanism is typical for cationic polymerization in the presence of Lewis acids as co-initiators. The expressions of number- and weight-average degrees of polymerization and Polydispersity Index are derived rigorously for a mechanism with free ions as the active species, but it is also applied to other mechanisms, e.g., ion pairs as active species. Plots of Polydispersity Index versus monomer conversion can be easily computed on a PC computer even though the expressions for the weight-average degree of polymerization and the concentration of residual initiator consist of confluent hypergeometric functions. Numerical calculations show that the Polydispersity Index of the resulting polymer approaches Mw/Mn = 2 with increasing rate constant of chain transfer. Addition of common ions led to narrower molecular weight distributions. For the polymerization of indene wit...

Tuncer Çaykara - One of the best experts on this subject based on the ideXlab platform.

  • synthesis of poly n isopropylacrylamide with a low molecular weight and a low Polydispersity Index by single electron transfer living radical polymerization
    Journal of Polymer Science Part A, 2011
    Co-Authors: Eylem Turan, Adem Zengin, Tuncer Çaykara
    Abstract:

    The single-electron transfer living radical polymerization (SET-LRP) method in the presence of chain transfer agent was used to synthesize poly(N-isopropylacrylamide) [poly(NIPAM)] with a low molecular weight and a low Polydispersity Index. This was achieved using Cu(I)/2,20-bipyridine as the catalyst, 2-bromopropionyl bromide as the initiator, 2-mercaptoethanol as the chain transfer agent (TH), and N,Ndimethylformamide (DMF) as the solvent at 90 C. The copper nanoparticles with diameters of 16 6 3 nm were obtained in situ by the disproportionation of Cu(I) to Cu(0) and Cu(II) species in DMF at 22 C for 24 h. The molecular weights of poly(NIPAM) produced were significantly higher than the theoretical values, and the polydispersities were less than 1.18. The chain transfer constant (Ctr) was found to be 0.051. Although the kinetic analysis of SET-LRP in the presence of TH corroborated the characteristics of controlled/living polymerization with pseudo-first-order kinetic behavior, the polymerization also exhibited a retardation period (k p > ktr). The influence of molecular weight on lower critical solution temperature (LCST) was investigated by refractometry. Our experimental results explicitly elucidate that the LCST values increase slightly with decreasing molecular weight. Reversibility of solubility and collapse in response to temperature well correlated with increased molecular weight of poly(NIPAM). VC 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 5116–5123, 2011

  • Synthesis of poly(N‐isopropylacrylamide) with a low molecular weight and a low Polydispersity Index by single‐electron transfer living radical polymerization
    Journal of Polymer Science Part A: Polymer Chemistry, 2011
    Co-Authors: Eylem Turan, Adem Zengin, Tuncer Çaykara
    Abstract:

    The single-electron transfer living radical polymerization (SET-LRP) method in the presence of chain transfer agent was used to synthesize poly(N-isopropylacrylamide) [poly(NIPAM)] with a low molecular weight and a low Polydispersity Index. This was achieved using Cu(I)/2,20-bipyridine as the catalyst, 2-bromopropionyl bromide as the initiator, 2-mercaptoethanol as the chain transfer agent (TH), and N,Ndimethylformamide (DMF) as the solvent at 90 C. The copper nanoparticles with diameters of 16 6 3 nm were obtained in situ by the disproportionation of Cu(I) to Cu(0) and Cu(II) species in DMF at 22 C for 24 h. The molecular weights of poly(NIPAM) produced were significantly higher than the theoretical values, and the polydispersities were less than 1.18. The chain transfer constant (Ctr) was found to be 0.051. Although the kinetic analysis of SET-LRP in the presence of TH corroborated the characteristics of controlled/living polymerization with pseudo-first-order kinetic behavior, the polymerization also exhibited a retardation period (k p > ktr). The influence of molecular weight on lower critical solution temperature (LCST) was investigated by refractometry. Our experimental results explicitly elucidate that the LCST values increase slightly with decreasing molecular weight. Reversibility of solubility and collapse in response to temperature well correlated with increased molecular weight of poly(NIPAM). VC 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 49: 5116–5123, 2011

Joel L. Plawsky - One of the best experts on this subject based on the ideXlab platform.