Progress 04/01/08 to 11/14/12
Outputs
OUTPUTS: Carbohydrates are structurally complex food biopolymers and their interactions include Van der Waals and ionic interactions as well as strong, specific interactions such as hydrogen bonds. Hydrogen bonds dominate phase behavior in many instances. In particular, the phase behavior of mixtures of carbohydrates and the solubility of monosaccharides, oligosaccharides and polysaccharides in water is important in food science and food product development determining physical properties such as gelation, melting point, glass transitions which affect the texture, stability, processability and shelf life of many foods. Initial applications of the association theory to predict phase behavior in polysaccharide blends has been done (Icoz and Kokini, 2008). Investigations have been carried out on both model and real carbohydrate mixtures (e.g. blends formed by two dextrans of different molecular weight and inulin-amylopectin systems). To adapt the model in such complex systems some approximations were necessary, thus leading to approximate and less accurate thermodynamic predictions. In this phase we present an extension of the advanced thermodynamic model based on Veytsman's contact theory to predict the contribution of hydrogen bonding interactions on the water activity carbohydrate concentration relationship for a glucose water system and a more complex dextran water system. The application of the model to aqueous solutions of model carbohydrates has been investigated in order to show how it can be used to obtain a molecular level understanding of the contribution of hydrogen bonding to the phase behavior of these types of mixtures. Free energy of mixing together with its second derivative was calculated in order to predict the phase behavior of glucose water and dextran water solutions. We also calculated the derivative of the free energy of mixing giving the chemical potential which leads to the calculation of water activity. The results of our calculations demonstrated the validity of the model by predicting the water activity. In contrast the Flory-Huggins theory is unable to predict water activity alone revealing the need to calculate the hydrogen bonding interactions and add them to the Flory Huggins free energy calculations in order to obtain correct predictions. Our calculations of the concentration of hydrogen bonds proved to be useful in explaining the difference between glucose and dextran and the role that hydrogen bonds play in contributing to these differences. The miscibility predictions showed that the Veytsman's model is also able to correctly describe the phase behavior of glucose and dextran. Our methodology can be applied to other carbohydrate mixtures composed of monosaccharide as well as carbohydrate polymers. This work represents an improvement in the current knowledge in understanding polysaccharide phase behavior. Our future investigations will focus on understanding how to extend the model to other carbohydrates and to multicomponent carbohydrate systems and validate these concepts with more complex carbohydrate mixtures with the aim of facilitating product development. PARTICIPANTS: Didem Icoz received her PhD in Food Science and Engineering from Rutgers University as result of this project and is currently employed at Ingredion in NJ. Francesca DeVito has conducted part of her postdoc on this project at the University of Illinois and is in the process of publishing what I believe will be a transformative paper in a premier journal in Chemical Engineering. Prof. Jozef Kokini from the University of Illinois (PI), previously at Rutgers University, collaborated with Prof. Paul Painter from Penn State University and Dr. Boris Veytsman from George Washington University. TARGET AUDIENCES: Food scientists, pharmaceutical scientists, chemical engineers, biologists, plant scientists, food engineers, food product developers, physical chemists, and microbiologists. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The phase behavior of mixtures of carbohydrates and the solubility of monosaccharides, oligosaccharides and polysaccharides in water is important in food science and food product development, determining physical properties such as gelation, melting point, glass transitions which affect the texture, stability, processability and shelf life of many foods. By predicting water activity from the molecular structure of glucose and dextrans we have for first time succeeded in developing a thermodynamic model capable of delivering this outcome. This offers a priori predictive principles that are very important to shelf-life stability of foods.
Publications
- Icoz, D. 2008. Understanding molecular and thermodynamic miscibility of carbohydrate biopolymers , PhD dissertation, Rutgers, The State University of New Jersey.
- Icoz, D.Z. and Kokini, J. 2008. Theoretical analysis of predictive miscibility of carbohydrate polymers - Software calculations for inulin-amylopectin systems. Carbohydrate Polymers, 72(1): 52-59.
- Painter, P.C. and Coleman, M.M. 2009. Self-contacts, self-concentration, and the composition dependence of the glass transition temperature in polymer mixtures. Macromolecules, 42(3): 820-829.
- De Vito, F., Veytsman, B., Painter, P. and Kokini, J.L. 2013. Simulation of the effect of hydrogen bonding contributions on the water activity of glucose and dextran at different volume fractions using the Veytsman model, Chemical Engineering Science (Submitted).
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Progress 04/01/11 to 11/14/11
Outputs
OUTPUTS: Our research focuses on hydrogen bond interactions and thermodynamic rules to accurately predict the phase behavior of carbohydrate polymer mixtures and their aqueous solutions. We developed for the first time a new thermodynamic lattice model based on the Veytsman's contacts point theory to describe multiple hydroxyl groups per molecule or monomer and thus the more complex occurrence of hydrogen bonds in the form of a network. The model has been successfully applied to a water-dextran solution and predictions were carried out estimating different values of the inter-association equilibrium constants describing hydrogen bonding between water molecule and dextran monomer with each component acting as both donor and acceptor. Our model was able to correctly predict the miscibility only provided right values of the selected constants. These findings were published in the Proceeding of ICEF11 Conference and presented at the IFT Annual meeting in 2011. The main challenge in the application of the model lies on the inaccessibility of direct experimental determination of the inter-association equilibrium constants. Therefore, this year we proposed a new approach based on water activity. We first formulated the equations of the chemical potentials for each component (solvent and solute) of the hydrogen bonding and non-specific contributions which were obtained by deriving the corresponding expressions of the Free Energy of Gibbs. For non-specific contribution the Flory-Huggins theory was used. The equation of the chemical potential was related to water activity and used to fit water activity experimental data. In order to prove its feasibility, the proposed method was applied to a simple system, a water-glucose solution. This choice was based on the consideration that glucose is the monomer of the more complex dextran polymer. The Veytsman's lattice model was then applied to the investigated solution assuming as reference units the single molecule for water and the single molecule for the glucose. Predictions were also carried out under the assumption of non-inter-association between water and glucose. The effect of the inter-association on the resulting distribution of hydrogen bonds in the system was investigated. The results of the data fitting obtained at the selected values of the equilibrium constants showed that very strong inter-association dominates the thermodynamic of the investigated system. The existence of a critical value of the investigated equilibrium constant above which no significant change in the calculated water activity occurs could be presumably due to the fact that the number of H-bonds does not change significantly. The values of the equilibrium constants able to fit the water activity data have been validated by the sign of the Free Energy of mixing and its second derivative. As part of our ongoing research, we are currently in the process of extending the methodology to the already-investigated water-dextran solution; for this purpose we will carry out water activity measurements. The manuscript of our study is currently in preparation. PARTICIPANTS: Jozef L. Kokini, Bingham Professor of Food Engineering, Department of Food Science and Human Nutrition, University of Illinois at Urbana/Champaign. Paul Painter, Professor of Polymer Science, Department of Materials Science and Engineering, Penn State University. Boris Veytsman, Advanced Engineering and Sciences, ITT Industries. Francesca De Vito, Postdoctoral Research Associate, Department of Food Science and Human Nutrition, University of Illinois at Urbana/Champaign. TARGET AUDIENCES: The outcomes of this project will open up new opportunities for the food industry by using in the formulation of a target final product. The designed thermodynamic rules will provide practical guidelines on how to choose food ingredients and as a result will improve the use of alternative agricultural ingredients in novel food products with new/improved functionalities. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
Miscibility can be defined as the formation of a single stable phase system where the components are intimately mixed at the molecular level. Molecular interaction and phase miscibility, in fact, affect many aspects of food development including final texture, processing, and shelf life-stability thus determining the overall quality of the product and finally consumer acceptance. Carbohydrates are complex biopolymers and main ingredients of food materials involving strong hydrogen bonds. So far, no thermodynamic rules able to accurately predict phase behavior (i.e, miscibility/immiscibility) of carbohydrate mixtures have been established, thus reducing the use of valuable alternative ingredients to costly trial and error. We have developed a new thermodynamic lattice model able to count the hydrogen bonds between the donors and acceptors groups. The peculiarity of our model lies in the ability to account for "contacts" rather than the chemical species allowed us for the first time to take into account multiple hydrogen bonds thus leading to more accurate predictions. The parametric analysis carried out in our study showed the significant effect of the inter-association in determining the thermodynamics of complex biopolymer mixtures and we have also proposed a valid method to quantitatively determine the equilibrium constants based on water activity experimental data. For its unique characteristics, our model is easier and more flexible to apply than the well-established association model. As further step in our research, in fact, we aim to extend and validate the model with more complex real food mixtures including inulin-amylopectin systems. The understanding gained from this project will improve the current knowledge of the polysaccharide phase behavior in order to facilitate product development and speed up the formulation of new products.
Publications
- De Vito F., Kokini J.L., Veytsman B. and Painter P. 2012. A parametric study of the inter-association equilibrium constants in hydrogen bonds interactions of water-polysaccharide mixtures. (In Preparation).
- De Vito F., Kokini J.L., Veytsman, B. and Painter, P. 2011. The phase behavior of carbohydrate polymer mixtures. In: Proceedings of ICEF11 International Congress on Engineering and Food, May 22-26, Athens, Greece.
- De Vito F., Kokini J.L., Painter P. and Veytsman B. 2011. Predicting the phase behavior of carbohydrate mixtures utilizing the Veytsman model. Presented at IFT11, Annual Meeting, June 11-14, New Orleans, LA.
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Progress 04/01/10 to 11/14/10
Outputs
OUTPUTS: The overall aim of this project is to develop quantitative thermodynamics based rules to accurately describe the phase behavior and to predict molecular miscibility or incompatibility of complex carbohydrate mixtures involving hydrogen bonds including solutions and blends. The theoretical problem associated with those biopolymers is related to their chemical structure and in particular the presence of multiple hydrogen bonding sites (hydroxyl groups)resulting in donors and acceptors on each repeating unit. Our research work has been focused on solving this theoretical problem and in the previous year we developed a new thermodynamic lattice model based on Veystman's contact point theory and the formulation of the mathematical expression of free energy of mixing (total and the contribution of hydrogen bonds) and its second derivative with respect to the composition as well as the stoichiometric equations describing the distribution of the hydrogen bonds in the system through ad hoc defined equilibrium constants. In this year's work, the validity of the model has been investigated in a model carbohydrate mixture and calculations of the free energy of mixing have been performed on polysaccharide solutions. In particular a water-dextran system was chosen as a case study since carbohydrate mixtures and real food systems involve water as their third component. In addition, components of the mixture exhibit both donor and acceptor groups thus self-association (inside the single component) and inter-association (between one component and the other) is possible. In this system there are four types of interactions: water-water, water-dextran, dextran-dextran and dextran-water and to each of a single specific equilibrium constant describing hydrogen bonds is associated. As a starting point of the calculations, the concentration of the hydrogen bonds of each type distributed in the system was determined by means of numerical solution of the stoichiometric equations. This allowed the quantitative evaluation of the free energy of mixing (including the free energy of hydrogen bonds and non-specific contribution) and its second derivative as a function of the volume fraction of the polysaccharide to predict miscibility/immiscibility in the investigated system. In order to use the model equilibrium constants are needed. The value of the equilibrium constant describing water-water hydrogen bonding was obtained using experimental data of infrared (IR) spectroscopy measurements. The self-association constant of dextran was evaluated assuming 2-propanol as model analogue. Finally, the values of the inter-association equilibrium constants cannot be obtained experimentally by means of IR spectroscopy due either to the presence of water in the system or to the partial/total immiscibility of the polysaccharides in the solvent used in the measurement. Due to unavailability of the inter-association constants, the thermodynamics of mixing was calculated by assuming different values of the equilibrium constants describing hydrogen bonding interactions between the polysaccharide and the solvent. The results of our study will be presented in a manuscript under preparation. PARTICIPANTS: Jozef L. Kokini, Bingham Professor of Food Engineering, Department of Food Science and Human Nutrition, University of Illinois at Urbana/Champaign. Paul Painter, Professor of Polymer Science, Department of Materials Science and Engineering, Penn State University. Dr Boris Veytsman, Advanced Engineering and Sciences, ITT Industries. Francesca De Vito, Postdoctoral Research Associate, Department of Food Science and Human Nutrition, University of Illinois at Urbana/Champaign. TARGET AUDIENCES: The prospective of our research project is to design predictive rules to establish miscibility/immiscibility of polymeric food ingredient mixtures thus enabling increased utilization of alternative valuable ingredients in food formulations to obtain targeted stable final products with new and/or improved functionalities. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Food materials are mainly composed of water and multiple polymeric molecules with different chemistry and properties and among them carbohydrates are the main ingredients. The phase behavior of mixtures of carbohydrates and the solubility of polysaccharides in water is an important problem in food science, determining physical properties such as gelation, melting point, glass transitions and hence the texture, stability, processability and shelf life of many foods. The parametric study carried out is able to show that the model can be used to obtain a qualitative understanding of the factors that determine the phase behavior of these types of mixtures. As part of our ongoing work we proposed a possible approach to obtain also the values of the equilibrium constants based on water activity data in solutions. The results of the research work will improve the knowledge in the field of phase behavior of carbohydrates and facilitate product development. At present, the absence of thermodynamic rules able to accurately predict miscibility or incompatibility in those systems limits the use of alternative valuable ingredients such as inulin for the formulation of targeted (low sugar/ nutrients added) stable products. Due to its general approach based on the distribution of the hydrogen bonds between the donors and acceptor groups occurring in the system, the proposed model has the advantage to be easily adapted to any system. The results of the project will give, then, the ability to design rules that can predict the miscibility/ incompatibility of polymeric food ingredients.
Publications
- No publications reported this period
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Progress 04/01/09 to 03/31/10
Outputs
OUTPUTS: Our research focuses on molecular interactions and thermodynamic miscibility of carbohydrate biopolymer systems involving in particular strong hydrogen bonds. The overall goal of our work is to develop quantitative thermodynamics rules to accurately describe the phase behavior of polysaccharides mixtures, solutions and gels. According to this, during this year we first accomplished the formulation of a new theoretical thermodynamic model for hydrogen bonding in the form of networks in polysaccharides and their aqueous solutions. Based on the chemistry of structurally complex carbohydrates, in fact the presence on each repeating unit of more than one functional group capable of hydrogen bonding allows formation of hydrogen bonds in the form of three-dimensional networks instead of a simple linear chain. For this reason, older models available for synthetic polymers could not be applied and a new theoretical approach was proposed in the development of our thermodynamic model. We utilized the contact point theory of Veytsman based on the number of donors and acceptor sites forming hydrogen bonds, and a partition function was obtained. The mathematical expression of the hydrogen bonds free energy and stoichiometric equation were formulated. Given the equilibrium constants, it is possible to quantitatively determine the terms of the total free energy of mixing, (i.e. nonspecific and hydrogen bonds interaction contributions)and its second derivative, thus to predict miscibility/incompatibility of the mixtures under investigation. The formulation and implementation of this thermodynamic model represented the starting point for our further investigations and the new developments accomplished in this year's work. Using the same approach, two new theoretical problems have been addressed to model the phase behavior of polysaccharides solutions and blends. We first considered that polysaccharides can engage in self contacts or intramolecular hydrogen bonds formed between groups in the same polymer chain and the previous thermodynamic model has been improved, including self contacts contributions. New and more accurate equations describing the terms of the free energy of mixing and its second derivative have been formulated. In addition to this, we observed that polysaccharides can crystallize, but in the aqueous environment found in foods, the melting point is lowered to the extent that they are in a solution or gel form. We used the same theoretical approach to handle the depression of melting point and new free energy equations have been formulated including the melting point of the crystal and the heat of fusion. Starting from those equations, the expression of the chemical potential was obtained. Calculations have not been performed yet and are part of our ongoing work. Finally a study on the conformation of polysaccharide in solution was carried out. The effect of hydrogen bond interactions on the conformational change was investigated by means of dynamic light scattering. The hydrodynamic radius was measured as a function of both temperature and concentration. The results of this study will be presented at IFT, 2010, Chicago, July 16-23. PARTICIPANTS: Jozef L. Kokini, Bingham Professor of Food Engineering, Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign. Paul Painter, Professor of Polymer Science, Department of Materials Science and Engineering, Penn State University. Dr. Boris Veytsman, Advanced Engineering and Sciences, ITT Industries. Dr. Francesca De Vito, Postdoc Research Associate, Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign. TARGET AUDIENCES: Our research project has the potential to improve the use of alternative sources in food formulation providing practical rules on how to choose these ingredients to obtain a target, stable final product. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
At present there is a lack of thermodynamic rules to predict phase behavior in polysaccharide mixtures. Our modeling approach based on Veystman's combinatorial approach with the hydrogen bonds distributed between the donor and acceptor groups in the system is new with respect to the original association theory. The new theoretical model accounts for multiple associations occurring in the form of hydrogen bonding networks in carbohydrate systems in the aqueous environments found in food products involving water as a third component, as well as intramolecular screening effects to accurately predict the miscibility/immiscibility of the polymeric food components of a certain solution and/or blend. The outcomes of the project will, therefore, represent a useful tool for the food industry in the development process providing practical guidelines on how to choose ingredients in food formulation in order to obtain a target product on a predictive basis. This will speed up ingredient replacement strategies, increasing the utilization of alternative agricultural ingredients in novel food products with new and improved functionalities.
Publications
- De Vito, F. and Kokini J.L. 2010. Understanding the fundamentals of molecular interactions and miscibility in carbohydrate biopolymer mixtures. IFT 2010 July 17-23, Chicago, Illinois.
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Progress 04/01/08 to 03/31/09
Outputs
OUTPUTS: Our research on molecular interactions and thermodynamic miscibility of food biopolymers focuses on structurally complex carbohydrate systems including blends and solutions with specific interactions such as strong hydrogen bonds. According to our overall aim to develop quantitative thermodynamics rules to accurately predict the phase behavior of polysaccharides mixtures including inulin-amylopectin system, we can summarize the work carried out in this first part as follows. A preliminary thermodynamic modeling for miscibility/immiscibility of hydrogen bonded carbohydrates mixtures using a Painter-Coleman association model has been completed providing the essential theoretical basis for the future work on this project. The Painter-Coleman model available for synthetic polymers with hydrogen bonds has been adapted ad hoc to more structurally complex polysaccharide blends through numerical calculations of the total free energy of mixing and its second derivative as well as the individual enthalpic, entropic, and hydrogen bonding contributions. Moreover, an exhaustive parametric analysis of the model has been carried out providing significant understanding of the thermodynamic basis of miscibility. According to the theoretical assumptions incorporated into the model, the adaptation of the Painter-Coleman model for multiple associating systems such as carbohydrate polymers enabled approximate miscibility/immiscibility predictions as shown by the results of the validation of the model in a inulin-amylopectin system. Based on these results, a more advanced thermodynamic model based on the Veytsman's contact point theory and the association theory had been proposed and is currently under development. According to this task, using the proposed approach we solved the two theoretical problems involved by the chemistry of the system consisting of how to describe real hydrogen bonding interactions between water-carbohydrate and carbohydrate-carbohydrate which occur in the form of a complex network instead of an easy chain. At present, the stechiometric equations enabling quantitative determination of hydrogen bond interactions and the mathematical expression of the free energy and its second derivative have been formulated. In addition, the mathematical code enabling numerical solutions of the obtained equations has been implemented in a program created ad hoc in C language. Finally, in order to obtain the parameters that can be used in the model including equilibrium constants describing the interactions, quantitative characterization of carbohydrates and their solutions by Fourier transform infrared (FTIR) spectroscopy has been started. These further investigations will provide insight into the interaction mechanisms, thus contributing to improve the state-of-art in food carbohydrate polymer science. PARTICIPANTS: Jozef L. Kokini, Bingham Professor of Food Engineering, Department of Food Science and Human Nutrition, University of Illinois at Urbana-Champaign. Paul Painter, Professor of Polymer Science, Department of Materials Science and Engineering, Penn State University. Dr. Boris Veytsman, Advanced Engineering and Sciences, ITT Industries. TARGET AUDIENCES: Thermodynamic modeling together with experimental investigations will prove helpful in understanding the molecular interactions and miscibility behavior in real complex food systems with strong hydrogen bonds. The generated knowledge will give the ability to design accurate and suitable rules that can predict if polymeric food ingredients are miscible or not in a certain formulation. The food industry will then be able to choose from a mix of functional ingredients those that will develop the most successful products on the basis of their miscibility/immiscibility which affects texture, active ingredient release, processing, and shelf-life stability, all of which are critical to consumer acceptance. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The thermodynamic model proposed upon completion of this research is based on Veystman's combinatorial approach with the hydrogen bonds distributed between the donor and acceptor groups in the system. Due to this more general approach respect to the original association theory, the new theoretical model accounts for multiple associations occurring in the form of hydrogen bonding networks in carbohydrate systems involving water as a third component. Once developed the model will be validated on real food systems including a inulin-amylopectin system, and the thermodynamic model will have the ability to quantitatively predict the miscibility/immiscibility of the polymeric food components of a certain solution and/or blend. The project outcomes will represent a useful tool for the food industry in the development process providing practical guidelines on how to choose ingredients in food formulation in order to obtain a target product on a predictive basis. The designed rules obtained upon completion of this study will speed up ingredient replacement strategies increasing the utilization of alternative agricultural ingredients in novel food products with new/improved functionalities.
Publications
- No publications reported this period
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