Progress 09/01/07 to 08/31/10
Outputs
OUTPUTS: EXECUTIVE SUMMARY: Deliquescence (Deq) is a first order phase transition from solid to solution that occurs at a relative humidity (RH) that is characteristic to the solid ingredient. Such dissolution of food components can lead to physical and chemical instabilities. This research performed under this funding addressed the phenomenon of deq., the significance of deq. to food industry, measurement techniques, the kinetics and thermodynamics of deq., the behavior of mixtures of deliquescent (deqt) salts (including phase diagrams and thermodynamics of binary systems), and consequences of deq. on chemical and physical stability of powder food and nutritional ingredient blends. PROGRESS: 2009/09 TO 2010/08 Obj 1: The experimental results of the 2 binary systems were compared to 5 theoretical or empirical models. Dynamic moisture sorption (DMS) studies of both systems were performed at 54% and 75% RH conditions for system 1 and 2 respectively. For the first system, 3 different particle sizes and 4 different compositions were stored in 54% RH desiccator to study effects of particle size and verification of the eutonic composition (EC). Results were compared to the solution phase study by a water activity meter and solid phase study by a DMS balance. Degree of contact was checked by optical microscopy. Obj 2: Experiments coupling the RH fluid cell and AFM were performed to understand the instrumental effects and verify the true RH inside the fluid cell. Preliminary experiments were performed to understand the effects of RH on a NaCl crystal as well as forces and distances involved in capillary condensation (CC) between NaCl crystals as well as between the binary systems described in obj. 1. Obj 3: Physical stability of a sausage seasoning and an acidic snack seasoning with anticaking agents (AA) were studied. The effects of AA, RH, RH cycling, and/or temperature on the moisture sorption behavior, flowability, and caking characteristics of powder systems were determined. The effects of AA on deq. of NaCl and citric acid were studied. Scanning electron microscopic images were obtained for the sucrose-citric acid (S-CA) mixture to verify the formation of crystalline bridges between components at higher RH. Obj 4: Long term chemical stability of the S-CA system was studied. 2 compositions and 4 RHs were employed to determine the effect of acidity and RH on the hydrolysis of sucrose. The kinetics and mechanism of hydrolysis of sucrose in the solid state were determined. The effects of deq. on chemical stability of vitamins B1, B6, and C in powder blends were studied. The effect of moisture on catechin chemical stability in green tea powder was studied. Obj 5: Moisture transfer from non-deqt. materials to deqt. materials was studied. Calculations using an established model have been made to predict the equilibrium RH of a closed system and water content of each component in the system. Non-deqt. material of interest was maltodextrin. Deqt. material of interest was fructose-citric acid (F-CA) mixture. Moisture transfer between amorphous ingredients and deqt. ingredients and effects on chemical stability of bioactive ingredients were studied. PARTICIPANTS: Lynne Taylor (PD), Lisa Mauer (CoPD), David Nivens (CoPD), Kaho Kwok (postdoctoral research assistant); Graduate training: Ashley Hiatt (graduate student), Adam Stoklosa (graduate student), Julieta Ortiz (graduate student); Undergraduate training: Diana Shi, Marie Loewen , Sarah Verkamp; Collaborator: Mario Ferruzzi (Foods and Nutrition) TARGET AUDIENCES: We have presented at national meetings (IFT, American Chemical Society, American Association of Pharmaceutical Scientists) and consulted with the food industry and have included minority undergraduate and graduate students on the program. Further, we have disseminated research findings through publication, workshops, short courses, and required undergraduate and graduate courses. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
IMPACT: 2009/09 TO 2010/08 Objective 1. The extended ZSR equation was the best model for each system. The eutonic composition for system 1 was 33% citric acid and 67% fructose, and for system 2 was 16% sodium chloride and 84% sucrose. The mutual deliquescence RH was 44.1% and 63.6% RH for system 1 and 2 respectively. The phase diagrams constructed can be used to predict the physical state of the mixtures at any RH (i.e. are they in a solution or a solid phase) as well as the amount of moisture in the systems. These results provide a better fundamental understanding of the relationship between the deliquescence phase transition, blend composition and the role of the environment. Objective 2. AFM images of sodium chloride crystals showed surface changes occurring at the deliquescence point (75% RH). New growth steps were formed probably due to recrystallization of the salt induced by the heat of the probe. It was found that this heat transfer from the instrument can cause complications since different local temperatures can affect the deliquescence point of the substance. Thus the true RH of the fluid cell should be determined by using the temperature measurement of the cell and the saturated vapor pressure. These results have highlighted the complexity of using AFM for the study of deliquescence. Objective 3. Anticaking agents have no effect on single deliquescent materials. Effective anticaking agents appear to work by acting as a physical barrier between heteroparticles in binary mixtures, thus reducing the deliquescence lowering phenomenon. This observation will enable the rational selection of anticaking agents for blends of deliquescent ingredients. Objective 4. Hydrolysis of sucrose was found to occur below the deliquescence point of the blend at 54% RH. This is a very significant result since it demonstrates that the deliquescence RH is not the lower limit of RH storage that defines a stable system. The reaction rate was faster at 64% RH and for samples containing more citric acid. The amount of water in the blends increased with time and was modeled so that this parameter could be incorporated into the rate equations describing the reaction course. The reaction rate was found to be first order with respect to sucrose and water concentration. Citric acid concentration remained constant throughout the experiment and hence it was not included in the rate equations. Capillary condensation may be involved in the reaction mechanism for the 54% RH samples, providing a source of bulk water to initialize the reaction. Objective 5. Theoretical calculations showed that the equilibrium RH of a fructose-citric acid eutonic mixture and maltodextrin in a closed system would be above 44.1% RH if the two substances are 1:1 by weight if maltodextrin was equilibrated at 64% RH initially. This means the fructose-citric acid mixture would deliquesce and it should form a homogeneous solution as predicted by the phase diagram. Experimental results showed close agreements to the predicted equilibrium RH.
Publications
- 1. Hiatt, A. N., Taylor, L. S. and Mauer, L. J. (2010) Influence of simultaneous variations in temperature and relative humidity on chemical degradation of two vitamin C forms and implications for shelf-life models. Journal of Agricultural and Food Chemistry 58(6):3532-3540.
- 2. Hiatt, A. N., Ferruzzi, M. G., Taylor, L. S. and Mauer, L. J. (2010) Deliquescence behavior and chemical stability of vitamin C forms (ascorbic acid, sodium ascorbate, and calcium ascorbate) and blends. International Journal of Food Properties (in press).
- 3. Mauer L. J. and Taylor, L. S. (2010). Deliquescence of Pharmaceutical Systems. Pharmaceutical Development and Technology. 15(6):582-594.
- 4. Mauer L. J. and Taylor, L. S. (2010). Water-Solids Interactions: Deliquescence. Annual Review of Food Science and Technology. 1:41-63.
- 5. Kwok, K., Mauer, L. J. and Taylor, L.S. (2010) Phase behavior and moisture sorption behavior of deliquescent powders. Chemical Engineering Science. 65:5639-5650.
- 6. Hiatt, A. N., Taylor, L. S. and Mauer, L. J. (2010). Effects of co-formulation of amorphous maltodextrin and deliquescent sodium ascorbate on moisture sorption and stability. International Journal of Food Properties (in press).
- 7. Kwok, K., Mauer, L. J. and Taylor, L.S. (2010) Kinetics of moisture-induced hydrolysis in powder blends stored at and below the deliquescence relative humidity: Investigation of sucrose-citric acid mixtures. Journal of Agricultural and Food Chemistry 58(22):11716-11724.
- 8. Ortiz, J., Kestur U., Taylor, L.S. and Mauer, L.J. (2009) Interaction of environmental moisture with powdered green tea formulations: Relationship between catechin stability and moisture-induced phase transformations. Journal of Agricultural and Food Chemistry. 57(11):4691-4697
- 9. Hiatt, A.N. Ferruzzi, M., Taylor, L.S., and Mauer, L. J. (2008) Impact of deliquescence on the chemical stability of vitamins B1, B6, and C in powder blends. Journal of Agricultural and Food Chemistry. 56 (15): 6471-6479.
- 10. Ortiz, J., Ferruzzi, M., Taylor, L.S. and Mauer, L.J. (2008) Interaction of Environmental Moisture with Powdered Green Tea Formulations: Effect on Catechin Chemical Stability. Journal of Agricultural and Food Chemistry 56:4068-4077.
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Progress 09/01/08 to 08/31/09
Outputs
OUTPUTS: Objective 1: The experimental results of the two binary systems were compared to five theoretical or empirical models (Raoult's law, and the Ross, Ferro Fontan-Chirife-Benmergui, Zdanovskii-Stokes-Robinson (ZSR), and extended ZSR equations). Dynamic moisture sorption studies of both systems were performed at 54% and 75% RH conditions for system 1 and 2 respectively. For the first system, three different particle sizes and four different compositions were stored in 54% RH desiccator to study the effects of particle size and verification of the eutonic composition. Results were compared to the solution phase study by the water activity meter and solid phase study by the dynamic moisture sorption balance. Degree of contact was checked by optical microscopy. Objective 2: Experiments coupling the RH fluid cell and AFM were performed to understand the instrumental effects and verify the true RH inside the fluid cell. The AFM was configured with RH and temperature sensors, an internal temperature probe was installed in the fluid cell, and condensation in the tubing was eliminated. Preliminary experiments were performed to understand the effects of RH on a sodium chloride crystal as well as forces and distances involved in capillary condensation between sodium chloride crystals as well as between the binary systems described in objective 1. Objective 3: Physical stability of a sausage seasoning and an acidic snack seasoning with anticaking agents (SiO2 or CaSiO3) were studied. The effects of anticaking agents, RH, RH cycling, and/or temperature on the moisture sorption behavior, flowability, and caking characteristics of powder systems were determined. The effects of anticaking agents (SiO2 or CaSiO3) on deliquescence of sodium chloride and citric acid were studied. Scanning electron microscopic images were obtained for the sucrose-citric acid mixture to verify the formation of crystalline bridges between components at higher RH. Objective 4: Long term chemical stability of the sucrose-citric acid (S-CA) system was studied. Two compositions (50-50 and 95-5 S-CA weight ratio) and four RHs were employed to determine the effect of acidity and RH on the hydrolysis of sucrose. The kinetics and mechanism of hydrolysis of sucrose in the solid state were determined. The effects of deliquescence on chemical stability of vitamins B1, B6, and C in powder blends were studied. The effect of moisture on catechin chemical stability in green tea powder was studied. Objective 5: Investigation of the moisture transfer from non-deliquescent materials to deliquescence materials is underway. Calculations using an established model have been made to predict the equilibrium RH of a closed system and water content of each component in the system. Non-deliquescent materials of interest are maltodextrin and beta-lactoglobulin. Deliquescent materials of interest are fructose-citric acid and sucrose-sodium chloride mixtures. Moisture transfer between amorphous ingredients and deliquescent ingredients and effects on chemical stability of bioactive ingredients were studied. PARTICIPANTS: Lynne Taylor (PD), Lisa Mauer (CoPD), David Nivens (CoPD), Kaho Kwok (postdoctoral research assistant); Graduate training: Ashley Hiatt (graduate student), Adam Stoklosa (graduate student), Julieta Ortiz (graduate student); Undergraduate training: Diana Shi, Marie Loewen , Sarah Verkamp; Collaborator: Mario Ferruzzi (Foods and Nutrition) TARGET AUDIENCES: We have presented at national meetings (IFT, American Chemical Society) and consulted with the food industry and have included minority undergraduate and graduate students on the program. Further, we have disseminated research findings through publication, workshops, short courses, and required undergraduate and graduate courses. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Objective 1. The extended ZSR equation was the best model for each system. The eutonic composition for system 1 was 33% citric acid and 67% fructose, and for system 2 was 16% sodium chloride and 84% sucrose. The mutual deliquescence RH was 44.1% and 63.6% RH for system 1 and 2 respectively. The phase diagrams constructed can be used to predict the physical state of the mixtures at any RH (i.e. are they in a solution or a solid phase) as well as the amount of moisture in the systems. These results provide a better fundamental understanding of the relationship between the deliquescence phase transition, blend composition and the role of the environment. Objective 2. AFM images of sodium chloride crystals showed surface changes occurring at the deliquescence point (75% RH). New growth steps were formed probably due to recrystallization of the salt induced by the heat of the probe. It was found that this heat transfer from the instrument can cause complications since different local temperatures can affect the deliquescence point of the substance. Thus the true RH of the fluid cell should be determined by using the temperature measurement of the cell and the saturated vapor pressure. These results have highlighted the complexity of using AFM for the study of deliquescence. Objective 3. Anticaking agents have no effect on single deliquescent materials. Effective anticaking agents appear to work by acting as a physical barrier between heteroparticles in binary mixtures, thus reducing the deliquescence lowering phenomenon. This observation will enable the rational selection of anticaking agents for blends of deliquescent ingredients. Objective 4. Hydrolysis of sucrose was found to occur below the deliquescence point of the blend at 54% RH. This is a very significant result since it demonstrates that the deliquescence RH is not the lower limit of RH storage that defines a stable system. The reaction rate was faster at 64% RH and for samples containing more citric acid. The amount of water in the blends increased with time and was modeled so that this parameter could be incorporated into the rate equations describing the reaction course. The reaction rate was found to be first order with respect to sucrose and water concentration. Citric acid concentration remained constant throughout the experiment and hence it was not included in the rate equations. Capillary condensation may be involved in the reaction mechanism for the 54% RH samples, providing a source of bulk water to initialize the reaction. Objective 5. Theoretical calculations showed that the equilibrium RH of a fructose-citric acid eutonic mixture and maltodextrin in a closed system would be above 44.1% RH if the two substances are 1:1 by weight if maltodextrin was equilibrated at 84% RH initially. This means the fructose-citric acid mixture would deliquesce and it should form a homogeneous solution as predicted by the phase diagram. These results confirm predictions of the phase diagram and show the impact of water transfer from a hygroscopic ingredient to a moisture sensitive blend.
Publications
- Ortiz, J., Kestur U., Taylor, L.S. and Mauer, L.J. (2009) Interaction of environmental moisture with powdered green tea formulations: Relationship between catechin stability and moisture-induced phase transformations. Journal of Agricultural and Food Chemistry 57:4691-4697.
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Progress 09/01/07 to 08/31/08
Outputs
OUTPUTS: Objective 1: Outputs: The model systems are: 1) fructose and citric acid and 2) sucrose and sodium chloride. Determination of the eutonic compositions of these binary systems has been completed using a water activity meter. The results are compared to theoretical predictions. For the first system, three different particle sizes and four different compositions were stored in 54% RH desiccator to study the effects of particle size and verification of the eutonic composition. Results are compared to the solution phase study by the water activity meter and solid phase study by the dynamic moisture sorption balance. Degree of contact is checked by optical microscopy. Objective 2: Outputs: Configuration of the AFM with the ability to perform experiments under various RH and temperatures. Determination of RH and temperature sensors and tubing configuration for achieving and maintaining desired RH. Installation of internal temperature probe within fluid cell is completed. Manual temperature calculation and control are achieved. Heated transfer line is constructed to prevent condensation in the tubing. Objective 3: Outputs: Physical stability of a sausage seasoning and an acidic snack seasoning with anticaking agents (SiO2 or CaSiO3) is studied. The effects of anticaking agents, RH, RH cycling and/or temperature, on the moisture sorption behavior, flowability and caking characteristics of powder systems are determined. The effects of anticaking agents (SiO2 or CaSiO3) on deliquescence of sodium chloride and citric acid are studied. Scanning electron microscopic images are obtained for the sucrose-citric acid mixture to verify the formation of crystalline bridges between components at higher RH. Objective 4: Outputs: Long term chemical stability of sucrose-citric acid (S-CA) system is studied. Two compositions (50-50 and 95-5 S-CA weight ratio) and four RHs are employed to determine the effect of acidity and RH on the hydrolysis of sucrose. The effects of deliquescence on chemical stability of vitamins B1, B6, and C in powder blends are studied. The effect of moisture on catechin chemical stability in green tea powder is studied. PARTICIPANTS: Lynne Taylor (PD) Lisa Mauer (CoPD) David Nivens (CoPD) Kaho Kwok (postdoctoral research assistant) Graduate training: Ashley Hiatt (graduate student) Adam Stoklosa (graduate student) Julieta Ortiz (graduate student) Undergraduate training; Diana Shi Marie Loewen Sarah Verkamp Collaborator Mario Ferruzzi (Foods and Nutritions TARGET AUDIENCES: We have presented at national meetings (IFT) and consulted with the food industry and have included minority undergraduate and graduate students on the program. Further, we have disseminated research findings through publication, workshops, short courses and required undergraduate and graduate courses. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
Objective 1 Outcomes/Impacts: For the first system, the experimental eutonic composition and RH are not the same as predictions from the ratio of molal solubilities and theoretical models. That indicates better interaction between water and the individual solute when both solutes are present. The second system shows less deviation from theoretical predictions. Smaller particles and a composition closer to the eutonic composition enhances the moisture uptake rate and extent of dissolution. Microscopy results show that dissolution is incomplete even at the eutonic composition, probably due to incomplete contact between the two components. These results can provide a better fundamental understanding of the phase transition and the effect of environmental conditions on the extent of moisture sorption. Objective 2 Outcomes/Impacts: Preliminary force pulls experiments of individual sucrose crystal showed increasing adhesion forces as RH increased. Deliquescence occurs at RH reading of 5% above RHo. This research can generate understanding on the interaction between deliquescent materials and moisture on the surface. The information should provide molecular insights on how deliquescence is initiated. Objective 3 Outcomes/Impacts: Anticaking agents have no effect on single deliquescent materials. A small portion of anticaking agents may be added to prevent deliquescent mixtures and food seasonings from caking. However, other environmental factors such as RH, temperature and pressure are also important in determining the effectiveness of the anticaking agent. The formation of crystalline bridges is not conclusive from the SEM images. AFM might be a better method to reveal the mechanism of caking. Results from this part are crucial in understanding how to prevent food products from caking and subsequently degrading. Objective 4 Outcomes/Impacts: Preliminary results showed that hydrolysis starts within 5 and 10 days at the RHo of S-CA (64%) for 50-50 and 95-5 respectively. A faster rate is observed at higher CA concentration (50-50). Hydrolysis begins after about a month and two months at 54% RH for 50-50 and 95-5 respectively. This indicates that the degradation products (fructose and glucose) enhance the moisture uptake of the mixture at a RH lower than RHo. A preliminary model show that the rate of hydrolysis is related to the amount of moisture sorbed and possibly the pH of the system. The S-CA system is of practical importance since this combination is present in many foods and the production of reactive monosaccharides could lead to a loss of functionality of bioactive components, enhanced Maillard browning, etc. Vitamin B1 and C degradation were significantly promoted above the RHo, while B6 was least affected by storage RH. The deliquescence lowering phenomenon enhanced moisture sorption of blends at RHs below the RHos. Ascorbate enhanced thiamin degradation. The chemical degradation of total and individual catechins in green tea powder formulations was significantly increased by exposure to increasing RH, and the degradation was exacerbated above 58% RH by the presence of citric acid and above 75% RH by the presence of ascorbic acid.
Publications
- Hiatt, A.N. Ferruzzi, M., Taylor, L.S., and Mauer, L. J. (2008) Impact of deliquescence on the chemical stability of vitamins B1, B6, and C in powder blends. Journal of Agricultural and Food Chemistry. 56 (15): 6471-6479
- Ortiz, J., Ferruzzi, M., Taylor, L.S. and Mauer, L.J. (2008) Interaction of Environmental Moisture with Powdered Green Tea Formulations: Effect on Catechin Chemical Stability. Journal of Agricultural and Food Chemistry 56:4068-4077
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