Progress 12/01/13 to 11/30/17
Outputs
Target Audience:The target audiences of the project included academic research scientists in food science and related fields as well as industrial research and development personnel in the food and related industries. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?The project has provided extensive training in photophysical principles and their application to monitor the physical and chemical properties of foods related to quality, stability, and safety. Three different groups of students have been affected. The post-doctoral fellow who managed this grant received extensive experience in managing a complex photophysical research project. Dr. Corradini has been recently hired as a tenure track assistant professor at the University of Massachusetts--Amherst and is developing a reserach program in which luminescence spectroscopy will play a significant part. Graduate students Yan Wang, Jun Liang, and Andrew Draganski received extensive experience in the application of photophysical probes to monitor food quality and stability, skills that they are currently using in their current professional positions. And finally, over 20 undergraduate students received direct experience in pursuing their own research projects investigating the luminescence properties of foods and how these properties can report on the quality and stability of foods, experience that will enhance their ability to be productive working citizens. How have the results been disseminated to communities of interest?By means of posters and talks at scientific conferences including annual meetings of the Institute of Food Technologists, the American Chemical Society, and the Biophysical Society, and at other international venues and by means of peer reviewed publications in the scientific literature. What do you plan to do during the next reporting period to accomplish the goals?
Nothing Reported
Impacts
What was accomplished under these goals?
Goal 1: We have identified and characterized a rich list of GRAS optical chromophores that can be used as sensors of the physical state of foods. These chromophores include the following groups of molecules. Synthetic azo and aryl dyes: These synthetic dyes include fast green, tartrazine, sunset yellow, allura red, citrus red and related molecules. Our work has confirmed that each of these molecules behaves as a molecular rotor, a molecule that contains internal groups whose internal rotation is sensitive to the local viscosity; the molecules exhibit negligible fluorescence emission in fluid solution (water) and increase in fluorescence intensity as the viscosity of the local environment increases. Work in the past year has confirmed that three of these molecules, fast green, tartrazine, and allura red, are sensitive to the gelation of gelatin. Upon cooling gelatin solutions, the fluorescence intensity of these molecules increases biphasically over a 2-3 hour time frame, with a fast phase over ~10-30 min and a slow phase out to 2-3 hours. The physical origin of these kinetic phases are currently under investigation using other spectroscopic and physical techniques including circular dichroism spectroscopy and dynamic rheology. Flavonols: These molecules include quercetin, fisetin, and related molecules including the synthetic analog 3-hydroxy flavone. Our work has confirmed that some of these molecules are sensitive to water activity in mixed water/alcohol model systems. This sensitivity reflects an excited state intermolecular proton transfer (ESIPT) process. In the excited state a proton can transfer from a hydroxyl group to a neighboring carbonyl group in the molecule. The newly formed tautomer has a lower excited state energy and thus a distinct lower energy emission band. The formation of the tautomer and the relative energy of the two emission bands (the normal and tautomer band) are modulated by presence of water in the local environment of the chromophore. Thus analysis of the two emission bands provides a sensitive measure of the water activity. We have investigated how the probes are sensitive to water activity in other model systems in which water activity is varied by addition of salts. Unfortunately, these studies do not confirm the generality of the phenomenon found in alcohol/water solutions. It thus appears that the probes may not be generally sensitive to water activity. Goal 2: Ongoing work on the sensitivity of phosphorescence probes to physical state of biomaterials has focused on using tryptophan phosphorescence to monitor how protein motions couple with solvent motions in glassy matrixes below and above the glass transition temperature of the matrix. Work on human serum albumin (single tryptophan) has revealed that a boundary layer of water on the protein surface modulates the dynamic coupling between matrix and solvent. This work clearly indicates that carefully controlling water content in solid proteins may have a dramatic impact on long term stability of dried and frozen foods and pharameucticals. Ongoing work using single tryptophan mutants of glucokinase investigates whether different structural regions within the protein couple differently with solvent motions.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
AlHasawi, Fatemah M., Corradini, Maria G., Rogers, Michael A., Ludescher, Richard D. (2017) Potential Applications of Luminescent Molecular Rotors in Food Science and Technology. Critical Reviews in Food Science and Nutrition, DOI: 10.1080/10408398.2017. 1278583.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Zelent, Bogumil, Bialas, Chris, Gryczynski, Ignacy, Chen, Pan, Chib, Rahul, Lewerissa, Karina, Corradini, Maria G., Ludescher, Richard D., Vanderkooi, Jane M., & Matschinsky, Franz M. (2017) Tryptophan Fluorescence Yields and Lifetimes of Human Glucokinase Used to Probe Conformational Changes. Journal of Fluorescence, 27, 1621-1631.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Draganski, Andrew R., Friedman, Joel M., & Ludescher, Richard D. (2017) Solvent-Slaved Dynamic Processes Observed by Tryptophan Phosphorescence of Human Serum Albumin. Biophysical Journal 112, 881-891.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
Corradini, Maria G., Demol, Maarten, Boeve, Jeroen, Ludescher, Richard D., & Joye, Iris J. (2017) "Fluorescence Spectroscopy as a Tool to Unravel the Dynamics of Protein Nanoparticle Formation by Liquid Antisolvent Precipitation." Food Biophysics, 12, 211-221.
- Type:
Journal Articles
Status:
Published
Year Published:
2017
Citation:
AlHasawi, Fatemah M., Fondaco, Derrick, Ben-Elazar, Karen, Ben-Elazar, Shirley, Fan, Yim Yan, Corradini, Maria G., Ludescher, Richard D., Bolster, Douglas, Carder, Gary, Chu, YiFang, Chung, Yongsoo, Kasturi, Prabhakar, Johnson, Jodee, & Rogers, Michael A. (2017) In vitro Measurements of Luminal Viscosity and Glucose/Maltose Bioaccessibility for Oat Bran, Instant Oats, and Steel Cut Oats. Food Hydrocolloids, 70, 293-303.
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Progress 12/01/14 to 11/30/15
Outputs
Target Audience:The target audiences of the project included academic research scientists in food science and related fields as well as industrial research and development personnel in the food and related industries. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has provided specialized training and professional development for three groups of young professionals: Undergraduate students: Our research model actively involves undergraduate students in this project. During this year 9 undergraduates were involved in research during the spring and fall semesters. These students work with an upper level undergraduate, a graduate student or the Assistant Research Professor on a day to day basis. Graduate students: Three graduate students conducted research on this project in partial fulfillment of their thesis requirements. They also mentored undergraduate students. How have the results been disseminated to communities of interest?The results of this project have been shared with relevant and interested communities at scientific conferences including the Biophysical Society, the Institute of Food Technologists and the American Chemical Society. What do you plan to do during the next reporting period to accomplish the goals?In the next phase (year) of the project we intend to pursue the following research areas: Edible probes of viscosity: Work will continue to investigate how the structure of hydrocolloids modulates the sensitivity of these molecular rotor probes to variations in solution viscosity, looking at a wide variety of carbohydrate and protein hydrcolloids. This work will include spectral measurements of the local water accessibility around the fluorescence probes using pyranine, a synthetic molecule sensitive to local water, to confirm that the differential response of these probes to hydrocolloids actually does reflect differences in the local environment surrounding the probe. Triplet probes of matrix mobility: We will continue our work characterizing the phosphorescence response of riboflavin to variations in matrix mobility in amorphous solids. This work will also focus on how riboflavin phosphorescence can be used to characterize how matrix composition modulates mobility using a variety of carbohydrate matrixes. Tryptophan as intrinsic probe of protein mobility: We hope to complete our studies of protein mobility in glucokinase in the final year of the project. Flavonols as probes of water activity: We will initiate a novel project to determine whether the fluorescence emission from flavonol probes is sensitive to variations in water activity, using alcohol/water solutions as model systems of variable water activity. This class of naturally occurring molecules exhibit excited state intramolecular proton transfer (ESIPT) in the excited state, generating a second lower energy emission band. This work is based on reports in the literature indicating that the rate of ESIPT is sensitive to hydrogen bonding.
Impacts
What was accomplished under these goals?
During this phase (year) of the project, our investigations included work in the following areas: Edible probes of viscosity: We continued investigating the sensitivity of the synthetic food dyes to viscosity, focusing on their response to changes in viscosity induced by hydrocolloid thickeners. This work revealed that synthetic food dyes such as sunset yellow, tartrazine, fast green, etc. did not respond uniformly to increases in viscosity induced by hydrocolloids such as alginate, xanthan gum, carboxy methyl cellulose, etc. In other words, that the fluorescence intensity of these synthetic azo and aryl dyes did not show comparable increases in fluorescence intensity in solutions of comparable viscosity either when compared among the hydrocolloid solutions or when these hydrocolloid solutions were compared with viscous solutions of glycerol, glycerol/water, and sugar/water. This differential response appears to reflect a difference between local viscosity that is sensed by the molecular-scale probe and bulk viscosity that is sensed by the macroscopic rheometer. Additional studies of the naturally occurring betalain dyes also provided evidence that these molecules also respond to changes in solution viscosity with an increase in fluorescence intensity. Triplet probes of matrix mobility: We began investigating the photophysical properties of riboflavin and its ability to sense mobility in a variety of amorphous solid matrixes. These studies demonstrated that riboflavin has appreciable phosphorescence intensity in rigid solid amorphous solutions at cryogenic temperatures (in glycerol/water solution) and at room temperature (in dry amorphous sucrose film). Correlation of measured intensity changes (decreases) with temperature indicated that the probe was quenched (intensity decreased) by matrix mobility in both the glassy state (due to activation of local beta relaxations) and at the glass transition (due to activation of global alpha relaxations.) Tryptophan as an intrinsic probe of protein mobility: We continued our investigations of the sensitivity of tryptophan phosphorescence to protein mobility in the enzyme glucokinase and its single tryptophan mutants.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Draganski, Andrew, Corradini, Maria, & Ludescher, Richard D. (2015) Revisiting Time-Resolved Protein Phosphorescence. Applied Spectroscopy 69, 1074-1081.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Joye, Iris J., Davidov-Pardo, Gabriel, Ludescher, Richard D., McClements, David J. (2015) Fluorescence Quenching Study of Resveratrol Binding to Zein and Gliadin: Towards a More Rational Approach to Resveratrol Encapsulation Using Water-Insoluble Proteins. Food Chemistry 185, 261-267
- Type:
Book Chapters
Status:
Published
Year Published:
2015
Citation:
Kashi, Ariella, Waxman, Sarah, Komaiko, Jennifer, Draganski, Andrew, Corradini, Maria, & Ludescher, Richard (2015) "Potential Use of Food Synthetic Colors as Intrinsic Luminescent Probes of the Physical State of Foods." In The Chemical Sensory Informatics of Food: Measurement, Analysis, Integration. Brian Guthrie, Jonathan Beauchamp, Andrea Buettner, and Barry K. Lavine, editors. ACS Symposium Series 1191, 253-267.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Corradini, Maria G. & Ludescher, Richard D. (2015) Making Sense of Luminescence From GRAS Optical Probes. Current Opinion in Food Science 4, 25-31.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Liang, Jun, Xia, Qiuyang, Wang, Simon, Li, Ji, Huang, Qingrong, & Ludescher, Richard D. (2015) Influence of Glycerol on the Molecular Mobility, Oxygen Permeability and Microstructure of Amorphous Zein Films. Food Hydrocolloids 44, 94-100.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Liang, Jun, Wang, Simon & Ludescher, Richard D. (2015) Effect of Additives on Physicochemical Properties in Amorphous Starch Matrices. Food Chemistry 171, 298-305.
- Type:
Journal Articles
Status:
Published
Year Published:
2015
Citation:
Liang, Jun & Ludescher, Richard D. (2015) Effects of Glycerol on the Molecular Mobility and Hydrogen Bond Network in Starch Matrix. Carbohydrate Polymers 115, 401-407
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Progress 12/01/13 to 11/30/14
Outputs
Target Audience:The target audiences of the project included academic research scientists in food science and related fields as well as industrial research and development personnel in the food and related industries. Changes/Problems:
Nothing Reported
What opportunities for training and professional development has the project provided?This project has provided specialized training and professional development for three groups of young professionals: Undergraduate students: Our research model actively involves undergraduate students in this project. During this year 10 undergraduates were involved in research during the spring, summer and fall semesters. These students work with an upper level undergraduate, a graduate student or the post-doc on a day to day basis. Graduate students: Two graduate students conducted research on this project in partical fulfillment of their thesis requirements. They also mentored undergraduate students. Post-doctoral fellow: This individual gained valuable experience both engaging in this research project and overseeing the daily work of graduate and undergraduate students. How have the results been disseminated to communities of interest?The results of this project have been shared with relevant and interested communities at scientific conferences including the Biophysical Society, the Institute of Food Technologists and the American Chemical Society. What do you plan to do during the next reporting period to accomplish the goals?During the next phase (year) of this project, we will continue our investigations in the following areas: Edible probes of viscosity: We will continue to investigate the sensitivity of the synthetic food dyes to viscosity, focusing on their response to changes in viscosity induced by hydrocolloid thickeners. We will also investigate whether some naturally occuring food dyes (betanins) are also sensitive to solution viscosity. Triplet probes of matrix mobility: We will investigate the photophysical properties of riboflavin and its ability to sense mobility in a variety of amorphous solid matrixes. Tryptophan as an intrinsic probe of protein mobility: We will investigate sensitivity of tryptophan phosphorescence to protein mobility in the enzyme glucokinase using wild type protein (with three tryptophans) and single tryptophan mutants. This work will test the generality of our findings with human serum albumin and thus further confirm the utility of tryptophan as a probe of sold matrix mobility in proteins
Impacts
What was accomplished under these goals?
Goals 1 & 2: Identify and characterize library of GRAS optical probes for their photophysical response to physical properties of foods We have investigated the photophysical properties of a range of potential probes of physical properties. These probes and the work done include: Synthetic food dyes as probes of viscosity: We continued our investigations of the azo and aryl synthetic food dyes--tartrazine, sunset yellow, fast green, etc.--in regards to their use as sensors of viscosity and physical state of foods. We confirmed that these dyes displayed the behavior of molecular rotors in model viscosity systems consisting of glycerol/water mixtures (0-100%) and sucrose/water mixtures at room temperature and pure glycerol as a function of temperature. A study of the 11 synthetic food dyes approved for use throughout the world indicated that all of them exhibit a similar, albeit variable, response in which the fluorescence intensity increases systematically with increase in solution viscosity. We have thus confirmed that these probes can function as viscosity sensors in food. Triplet probes of matrix mobility: Detailed studies were completed of the sensitivity of the phosphorescence signal of the triplet optical probes tryptophan, tyrosine, erythrosin, and vanillin to changes in matrix dynamics in the glycerol/water model system from 77K to room temperature. These studies confirmed the utiltiy of all four probes to monitor changes in matrix mobility in amorphous solids in both the glass state (where the probes sense changes in local mobility due to activation of beta relaxations) and the melt above Tg (where the probes sense changes in global mobility due to activation of alpha relaxations). These studies confirm the utitlity of these triplet state probes to monitor matrix dynamics in amorphous solids. Intrinsic probes of protein mobility: A detailed study of the phosphorescence from the single tryptophan in human serum albumin in amorophous solids over the temperature range from 77K to room temperature was completed. This work provided evidence that tryptophan phosphorescence can be used to effectively monitor changes in protein dynamics within an amorphous solid matrix (using glycerol/water at low temperature and solid sucrose near room temperature) and to investigate how water modulates the protein dynamics within the amorphous matrix. Probes of oil properties: We studied whether the fluorescence signal from vitamin E (alpha tocopherol) can provide indications of changes in frying oil quality; unfortunately, this work demonstrated that no signal provided an unambiguous indicator of quality. In an unanticipated development, we used citrus red (an oil soluble mono azo food dye) to investigate oil viscosity in confined networks containing different amounts of crystallized fat. This work demonstrated that the probe fluorescence signal increased as the extent of the crystal network increased, and that the fractal dimensionality of the fat network provided the best correlation with the increase in fluorescence detected.
Publications
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Liang, Jun, Corradini, Maria G. & Ludescher, Richard D. (2014) Influence of Antioxidant Structure on Local Molecular Mobility in Amorphous Sucrose. Carbohydrate Research 383, 14-20.
- Type:
Journal Articles
Status:
Published
Year Published:
2014
Citation:
Du, H., Kim, C., Corradini, M.G., Ludescher, R.D. & Rogers, M.A. (2014) Micro-Viscosity of Liquid Oil Confined in Colloidal Fat Crystal Networks. Soft Matter 10, 8652-8658.
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