Progress 09/01/04 to 08/31/09
Outputs
OUTPUTS: Research, in the context of graduate education, was conducted and analyzed. The data collected further supported a new reaction mechanims (bases of proposal) by which phenolic compounds alter the pathways of the Maillard reaction (a key food reaction). The findings from this project were presented at a symposium in Switzerland). PARTICIPANTS: Devin G Peterson and Deshou Jiang TARGET AUDIENCES: The food industry and academia. PROJECT MODIFICATIONS: Nothing significant to report during this reporting period.
Impacts
The flavor properties of cereal food products have been reported to be negatively influenced when formulated with whole grain versus refined flour. The objective of this study was to investigate the reactivity of the phenolic compounds in whole grain on the mechanisms of the Maillard reaction in low moisture high temperature simulated roast model systems. Using isotope labeling techniques, the hydroxycinnamic acids were reported to be reactive with key transient Maillard reaction products, such as hexose sugar fragments. The structure of one ferulic acid-Maillard reaction reaction product was characterized by NMR and MS and identified as 6-(4-hydroxy-3-methoxyphenyl)-5-(hydroxymethyl)-8-oxabicyclo[3.2.1]-o ct-3-en-2-one. Based on retrosynthesis, this reaction product was suggested to be generated by a [5+2] cycloaddition reaction between a dehydrated/cyclized degradation product of 3-deoxy-2-hexosulose and a decarboxylated ferulic acid. In summary, ferulic acid was reported to influence Maillard chemistry, a key mechanism of flavor generation.
Publications
- Jiang, D. and D.G. Peterson. 2009. Hydroxycinnamic acid-Maillard reactions: Insights into flavor development of whole grain foods. 12th Weurman Symposium Proceedings. Interlaken, Switzerland. http://www.weurman2008.ethz.ch/
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Progress 10/01/07 to 09/30/08
Outputs
OUTPUTS: A new graduate student was recruited and mentored to investigate the role of phenolic-Maillard reactions on food quality/health promotion. Optimization of the analytical methods for identification/quantification of phenolic-Maillard reactions in animal models was thoroughly developed. Related C13 labeled internal standards and the analytes of interest were synthesized in the lab. The results from related assays were presented to university and industrial audiences. PARTICIPANTS: Smaro Kokkinidou, graduate student. TARGET AUDIENCES: Academy/Industry in both the food and biomedical area. PROJECT MODIFICATIONS: Not relevant to this project.
Impacts
The development of accurate analytical techniques to measure phenolic-Maillard reaction products in animal models provided an important first step to test a new proposed bioactive of dietary phenolic compounds in vivo.
Publications
- No publications reported this period
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Progress 01/01/07 to 12/31/07
Outputs
OUTPUTS: Research, in the context of graduate education, was conducted and analyzed. The data collected further supported a new reaction mechanims (bases of proposal) by which phenolic compounds alter the pathways of the Maillard reaction (a key food and biological reaction). The findings from this project were presented at a symposium in Germany.
PARTICIPANTS: Devin G Peterson (Principal Investigator), Yudo Noda (Graduate Student), Vandana Totlani (Graduate Student)
TARGET AUDIENCES: The US food industry, academia and beyond. The biomedical industry and academia. Findings from this grant have been incorporated into my Flavor Chemistry course at Penn State.
Impacts
The overall goal of this project is to define the reactivity of flavonoids on Maillard chemistry, ultimately to provide a novel link between phenolic-Maillard chemistry and food quality (i.e. processed flavor, toxicity, health promotion). Our results thus far have demonstrated indicated that flavanols quenched Maillard generated sugar-fragments (key transient intermediate precursors of MRP) primarily by ionic electrophilic aromatic substitution reactions and thereby inhibit the generation of Maillard reaction products (MRPs). Based on this ionic reaction mechanim, as anticipated, the polyhydroxyl benzene ring configuration (or the configuration of electron donating groups) was observed to be a key parameter which influenced the reactivity of phenolic compounds as a Maillard reaction inhibitor. A benzene ring structure with the electron donating groups in a meta-configuration was more reactive than the ortho-configuration in suppressing the concentration of key Maillard
intermediate reaction products (alpha-hydroxycarbonyl and alpha-dicarbonyl compounds) by electrophilic aromatic substitution reactions. Consequently, the A-ring of flavan-3-ols was suggested to be the main reactive site which impacted Maillard chemistry in these model systems. Furthermore, this new phenolic-Maillard reaction mechanism provides a new technology to control Maillard product generation in food products, as well as an improved understanding of the chemistry and fate of these phenolics during processing and storage. An example of a direct application from this work is that the fundamental knowledged gained from this project has been utilized to initiate an applied sponsor research project with Dairy Management Inc. to improve the quality of aspetic milk (use of natural product phenolics to inhibit the Maillard reaction in milk). Furthermore, others have used our new reaction mechanism to investigate how dietary phenolic may influence health promotion [Lo. C.Y., Li, S., Tan,
D., Pan, M.H., Sang, S., Ho, C.T. Trapping reactions of reactive carbonyl species with tea polyphenols in simulated physiological conditions. Mol Nutr Food Res. 2006 Dec;50(12):1118-28.]
Publications
- Peterson, D. G. and Y. Noda. 2007. Role of Phenolic Reactions on Maillard Reaction Flavours. Proc. 8th Wartburg Symposium on Flavor Chemistry & Biology, Eisenach, Germany. Symposium Proceedings. (In Press)
- Noda, Y. and D. G. Peterson. 2007. Structure-reactivity relationships of flavan-3-ols on product generation in aqueous glucose/glycine model systems, J. Agric. Food Chem, 55: 3686-3691.
- Totlani, V. M. and D. G. Peterson. 2007. Influence of Epicatechin Reactions on the Mechanisms of Maillard Product Formation in Low Moisture Model Systems. J. Ag. Fd. Chem., 55: 414-420.
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Progress 01/01/06 to 12/31/06
Outputs
The identification and structural elucidation of novel epicatechin-maillard reaction products were studied in phase 1; while the influence of epicatechin reactions on the mechanisms of the Maillard reaction under simulated food processing roast conditions was investigated in phase 2. Phase 1: Previously our group reported via labeling experiments that epicatechin in Maillard reaction aqueous glucose-glycine model systems formed adduct reaction products with C2, C3, and C4 sugar fragments. In a current study, we investigated the identity of the sugar fragment precursors responsible for adduct generation by directly comparing the liquid chromatography-mass spectrometry properties of these reported epicatechin (EC)-sugar fragments adducts with those generated from reactions consisting of only EC and well known Maillard-generated glucose fragments (i.e., glyoxal, glycolaldehyde, methylglyoxal, glyceraldehyde, etc.). The structural properties of an EC-methylglyoxal adduct
reaction product were also analyzed by NMR. The most likely precursors for the C2, C3, and C4 sugar moiety of the EC-sugar fragment adducts were identified as glyoxal, hydroxyacetone, and erythrose, respectively. 1H NMR analysis of the EC-methylglyoxal indicated that the analyte underwent rapid conformational/constitutional exchange. Using cold temperature (minus 25C) two dimensional NMR analyses (heteronuclear multiple bond coherence, heteronuclear multiple quantum coherence, and 1H-1H correlation spectroscopy), the structure of one of the isomers was reported to consist of a covalent linkage between the C1 position of the methylglyoxal and either the C6 or the C8 position of the EC A ring, presumably generated by hydroxyalkylation and aromatic substitution reactions. Phase 2: The influence of the polyphenolic compound epicatechin on Maillard chemistry was investigated under simulated roast conditions (10% moisture at 220C for 10 min). Quantitative gas chromatography (GC) analysis
indicated that the addition of epicatechin to glucose or fructose/glycine model systems significantly reduced the generation of hydroxyacetone, 2-methylpyrazine, 2,3,5-trimethylpyrazine, furfural, 2-acetylfuran, 5-methylfurfural, 2(5H)-furanone, 2-acetylpyrrole, and furfuryl alcohol. These analytes were reported to be primarily generated from intact C2, C3, C4, C5, and C6 sugar fragments based on gas chromatography/mass spectrometry quantitative isotopomeric analysis a 1:1 13C6:12C6 hexose sugar-glycine model system. Liquid chromatography/mass spectrometry qualitative isotopomeric analysis of a 1:1 13C6:12C6 hexose sugar/glycine/epicatechin model systems confirmed epicatechin reacted with Maillard reactants in the model systems; two main reaction products were reported, epicatechin-C5 and -C6 sugar fragment adducts. In addition, LC/MS analysis of a model system consisting of only 3-deoxy-2-hexosulose and epicatechin identified 3-deoxy-2-hexosulose as a precursor of the epicatechin-C5
and -C6 sugar fragment adducts reaction products. These results imply that epicatechin quenched 3-deoxy-2-hexosulose (a key source C6 to C1 sugar fragments) and consequently inhibited Maillard product formation.
Impacts
This research provides new information for how phenolic chemistry impacts the quality of processed food (i.e. flavor quality) as well as provides a new mechanism for explaining the vast epidemiological evidence supporting a positive relationship between dietary intake of polyphenolic compounds and health promotion.
Publications
- Totlani, V.M. and Peterson, D.G. 2006. Epicatechin Carbonyl-Trapping Reactions in Aqueous Maillard Systems: Identification and Structural Elucidation. J. Agric. Food Chem. 54: 7311-7318.
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Progress 01/01/05 to 12/31/05
Outputs
Phenolic compounds were reported to have a dramatic impact (can function as an inhibitor) the Maillard reaction via novel mechanisms; phenolics have not been previously considered reactants. Using an aqueous model Maillard system we recently reported via labeling studies (13C, 15N) that epicatechin (phenolic) quenches C2, C3, and C4 sugar fragments or key transient precursors (reactivity carbonyl compounds) of the Maillard reaction. Furthermore, in a dry model system, C6 sugar moiety (deoxyosone) was reported to be quenched by epicatechin.
Impacts
The Maillard reaction, a carbonyl-amino condensation reaction, is a ubiquitous chemical reaction in life and a well documented critical food (flavor, color, nutritional value, toxicity) and biological reaction (aging, inflammation, cardiovascular disease, etc.). Likewise, improving our understanding of how phenolic chemistry influences the mechanisms of this critical food reaction may provide the new technology for improvements in food quality (i.e. flavor properties).
Publications
- Totlani, V.A. and Peterson, D. G. 2005. Reactivity of epicatechin in aqueous glycine and glucose maillard reaction models: quenching of C2, C3 and C4-sugar fragments. J. Ag. Fd. Chem. 53: 4130-4135.
- Peterson, D.G. and Totlani, V.A. 2005. Influence of flavonoids on the thermal generation of aroma compounds. in Phenolics in Foods and Natural Health Products, New York, ACS Symposium Series #909, September 7-11, 2003, pg 143-160.
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Progress 01/01/04 to 12/31/04
Outputs
Addition of epicatechin to model Maillard reaction and food systems was found to inhibit the formation of thermally generated flavor compounds. It is proposed that epicatechin quenches the intermediate C2, C3, C4-sugar fragments, essential for the generation of Maillard type aroma compounds (i.e. pyrazine, diacetyl). Our objective was to define mechanisms of how epicatechin alters the chemical pathways in Maillard-type reactions using Carbon-13 labeled Maillard precursors. Eight aqueous Maillard model reactions comprising of: (1) glucose-glycine, (2) glucose-glycine-epicatechin, (3) glucose(12C6) : glucose (13C6) (1:1)-glycine with and without epicatechin, (4) glucose [13C1, 13C2]-glycine, (5) glucose-glycine 15N, (6) glucose:glycine[15N]/glycine[14N] (1:1), (7) glucose-glycine [13C2], (8) glucose-glycine [13C2, 15N] and epicatechin. All reactions were preformed in phosphate buffer (150ml, 0.1M, pH7.0), with all reactants at 0.01M and heated at 125C-30min. The MRP's
were extracted by diethyl ether and analyzed by gas chromatography-mass spectrometry (GC/MS). The non-volatiles were absorbed over an Amberlite column, eluted with methanol, and were analyzed by liquid chromatography-electrospray ionization-mass spectrometry (LC-ESI-MS). Addition of epicatechin inhibited the formation of pyrazine, 2,5-dimethylpyrazine and 2,3-butanedione all which were shown to be formed by C2, C3 and C4 sugar fragments, respectively as determined by Carbohydrate Module Labeling (CAMOLA) studies. The mass spectra for the non-volatile components in reaction mix containing labeled sugar and epicatechin showed signals with mass differences of (M+2,3 or 4) compared to samples without labeled sugar suggesting that epicatechin was quenching the by C2, C3 and C4 sugar fragments. The following ions were present in 1:1 ratio for 347/349(C2), 361/364(C3) and 633/636(C3) and 371/375(C4). These ions were only in epicatechin enriched samples. This work indicated that epicatechin
may inhibit volatile flavor generation via quenching key intermediate Maillard reaction precursors and ultimately may be used to control a critical reaction in processed food products.
Impacts
This project will provide the food industry with valuable information to improve control of the Maillard reaction (i.e. flavor-development); a critical reaction in processed food products.
Publications
- No publications reported this period
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