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Anema SG. Heat-induced changes in caseins and casein micelles, including interactions with denatured whey proteins. Int Dairy J 2021. [DOI: 10.1016/j.idairyj.2021.105136] [Citation(s) in RCA: 12] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
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Wang Y, Zhang Z, Li Y, Jiang H, Kumah Mintah B, Dabbour M, He R, Ma H. Lysinoalanine formation and conformational characteristics of rice dreg protein isolates by multi-frequency countercurrent S-type sonochemical action. ULTRASONICS SONOCHEMISTRY 2020; 69:105257. [PMID: 32688247 DOI: 10.1016/j.ultsonch.2020.105257] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/23/2020] [Revised: 06/20/2020] [Accepted: 07/08/2020] [Indexed: 06/11/2023]
Abstract
The influences of multi-frequency countercurrent S-type ultrasound (MFSU), with various frequency modes, on lysinoalanine (LAL) formation and conformational characteristics of rice dreg protein isolates (RDPI) were investigated. The ultrasonic operating mode with dual-frequency combination (20/40 kHz) indicated lower LAL content and higher protein dissolution rate of RDPI compared with that of other ultrasound operating modes. Under the dual-frequency ultrasound mode of 20/40 kHz, acoustic power density of 60 W/L, time of 20 min, and temperature of 35 °C, the relative reduction rate of LAL of RDPI reached the highest with its value of 26.95%, and the protein dissolution rate was 71.87%. The changes in chemical interactions between protein molecules indicated that hydrophobic interactions and disulfide bonds played a considerable role in the formation of LAL of RDPI, especially the reduction of g-g-g and g-g-t disulfide bond. Alterations in microstructure showed that ultrasonication loosened the protein structure and created more uniform protein fragments of RDPI. In conclusion, using MFSU in treating RDPI was an efficacious avenue for minimizing LAL content and modifying the conformational characteristics of RDPI.
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Affiliation(s)
- Yang Wang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Institute of Applied Chemistry and Biological Engineering, Weifang Engineering Vocational College, 8979 Yunmenshan South Road, Qingzhou, Shandong 262500, China
| | - Zhaoli Zhang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Institute of Applied Chemistry and Biological Engineering, Weifang Engineering Vocational College, 8979 Yunmenshan South Road, Qingzhou, Shandong 262500, China
| | - Yihe Li
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; College of Grain Engineering, Food&Drug, Jiangsu Vocational College of Finance & Economics, 8 Meicheng East Road, Huaian, Jiangsu 223001, China
| | - Hui Jiang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China
| | - Benjamin Kumah Mintah
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China
| | - Mokhtar Dabbour
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Department of Agricultural and Biosystems Engineering, Faculty of Agriculture, Benha University, P.O. Box 13736, Moshtohor, Qaluobia, Egypt
| | - Ronghai He
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Institute of Food Physical Processing, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China.
| | - Haile Ma
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Institute of Food Physical Processing, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China
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Hellwig M, Henle T. Maillard Reaction Products in Different Types of Brewing Malt. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2020; 68:14274-14285. [PMID: 33205653 DOI: 10.1021/acs.jafc.0c06193] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Individual Maillard reaction products (MRPs), namely, free and protein-bound glycated amino acids as well as dicarbonyl compounds, were quantitated in various types of brewing malt using chromatographic means. Among the protein-bound glycated amino acids, which were analyzed following enzymatic hydrolysis, N-ε-fructosyllysine was the dominating compound in light (EBC < 10) and dark (10 < EBC < 500) malts, accounting for up to 15.9% of lysine derivatization, followed by N-ε-maltulosyllysine (light malts, up to 4.9% lysine derivatization) or pyrraline (dark malts, up to 10.4% lysine derivatization). Roasting of malt led to the degradation of most of the protein-bound glycated amino acids. The same trends were visible for free glycated amino acids. A novel MRP-derived Strecker aldehyde, namely, 5-(2'-formyl-5'-hydroxymethylpyrrol-1'-yl)-pentanal (pyrralinal), was detected in dark malt. The most abundant 1,2-dicarbonyl compound in malt samples was 3-deoxyglucosone (up to 9 mmol/kg), followed by 3-deoxymaltosone (up to 2 mmol/kg). Only few MRPs such as 5-hydroxymethylfurfural, furfural, the dicarbonyl compounds glyoxal, methylglyoxal, and diacetyl as well as protein-bound rhamnolysine and MG-H1 correlated with the malt color. A comparison of MRPs present in malt with corresponding amounts in beer points to neoformation of MRPs such as MG-H1 and 3-deoxygalactosone during the brewing process.
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Affiliation(s)
- Michael Hellwig
- Chair of Food Chemistry, Technische Universität Dresden, D-01062 Dresden, Germany
| | - Thomas Henle
- Chair of Food Chemistry, Technische Universität Dresden, D-01062 Dresden, Germany
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Zhang Z, Wang Y, Jiang H, Dai C, Xing Z, Kumah Mintah B, Dabbour M, He R, Ma H. Effect of dual-frequency ultrasound on the formation of lysinoalanine and structural characterization of rice dreg protein isolates. ULTRASONICS SONOCHEMISTRY 2020; 67:105124. [PMID: 32298973 DOI: 10.1016/j.ultsonch.2020.105124] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/20/2019] [Revised: 03/26/2020] [Accepted: 04/06/2020] [Indexed: 06/11/2023]
Abstract
The effect of dual-frequency ultrasound treatment with different working modes on the lysinoalanine (LAL) formation and structural characterization of rice dreg protein isolates (RDPI) was studied during alkaline exaction processing. Ultrasonic notably decreased the LAL amount of RDPI and enhanced the protein dissolution rate. The LAL content of RDPI, especially sequential dual frequency 20/40 kHz, decreased by 12.02% (P < 0.05), compared to non-sonicated samples. Herein, the protein dissolution rate was higher. The changes in sulfhydryl groups was positively correlated with the LAL formation. The amino acids (AA) such as threonine (Thr), lysine (Lys), and arginine (Arg) were reduced, resulting in a decrease in LAL content following sonication. Besides, ultrasonication altered protein secondary structure by reducing random coil and β-sheet contents, while α-helix and β-turn contents increased. Alterations in the surface hydrophobicity, particle size, particle size distribution, and microstructure indicated more irregular fragment with microparticles of RDPI by sonochemical treatment. Thus, ultrasound treatment may be a new and efficacious process for controlling the LAL generation in prepared-protein food(s) during alkali extraction.
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Affiliation(s)
- Zhaoli Zhang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Institute of Applied Chemistry and Biological Engineering, Weifang Engineering Vocational College, 8979 Yunmenshan South Road, Qingzhou, Shandong 262500, China
| | - Yang Wang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Institute of Applied Chemistry and Biological Engineering, Weifang Engineering Vocational College, 8979 Yunmenshan South Road, Qingzhou, Shandong 262500, China
| | - Hui Jiang
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Institute of Food Physical Processing, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China
| | - Chunhua Dai
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Institute of Food Physical Processing, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China
| | - Zheng Xing
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China
| | - Benjamin Kumah Mintah
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China
| | - Mokhtar Dabbour
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Department of Agricultural and Biosystems Engineering, Faculty of Agriculture, Benha University, P.O. Box 13736, Moshtohor, Qaluobia, Egypt
| | - Ronghai He
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Institute of Food Physical Processing, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China.
| | - Haile Ma
- School of Food and Biological Engineering, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China; Institute of Food Physical Processing, Jiangsu University, 301 Xuefu Road, Zhenjiang, Jiangsu 212013, China
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DALLAS DAVIDC, SANCTUARY MEGANR, QU YUNYAO, KHAJAVI SHABNAMHAGHIGHAT, VAN ZANDT ALEXANDRIAE, DYANDRA MELISSA, FRESE STEVENA, BARILE DANIELA, GERMAN JBRUCE. Personalizing protein nourishment. Crit Rev Food Sci Nutr 2017; 57:3313-3331. [PMID: 26713355 PMCID: PMC4927412 DOI: 10.1080/10408398.2015.1117412] [Citation(s) in RCA: 57] [Impact Index Per Article: 8.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Proteins are not equally digestible-their proteolytic susceptibility varies by their source and processing method. Incomplete digestion increases colonic microbial protein fermentation (putrefaction), which produces toxic metabolites that can induce inflammation in vitro and have been associated with inflammation in vivo. Individual humans differ in protein digestive capacity based on phenotypes, particularly disease states. To avoid putrefaction-induced intestinal inflammation, protein sources, and processing methods must be tailored to the consumer's digestive capacity. This review explores how food processing techniques alter protein digestibility and examines how physiological conditions alter digestive capacity. Possible solutions to improving digestive function or matching low digestive capacity with more digestible protein sources are explored. Beyond the ileal digestibility measurements of protein digestibility, less invasive, quicker and cheaper techniques for monitoring the extent of protein digestion and fermentation are needed to personalize protein nourishment. Biomarkers of protein digestive capacity and efficiency can be identified with the toolsets of peptidomics, metabolomics, microbial sequencing and multiplexed protein analysis of fecal and urine samples. By monitoring individual protein digestive function, the protein component of diets can be tailored via protein source and processing selection to match individual needs to minimize colonic putrefaction and, thus, optimize gut health.
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Affiliation(s)
- DAVID C. DALLAS
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
- Foods for Health Institute, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - MEGAN R. SANCTUARY
- Foods for Health Institute, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
- Department of Nutrition, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - YUNYAO QU
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - SHABNAM HAGHIGHAT KHAJAVI
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
- Department of Food Science and Technology, Science and Research Branch, Islamic Azad University, Tehran, Iran
| | - ALEXANDRIA E. VAN ZANDT
- Department of Nutrition, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - MELISSA DYANDRA
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - STEVEN A. FRESE
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
- Foods for Health Institute, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - DANIELA BARILE
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
- Foods for Health Institute, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
| | - J. BRUCE GERMAN
- Department of Food Science and Technology, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
- Foods for Health Institute, University of California, Davis, One Shields Avenue, Davis, CA 95616, United States
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Xue J, Ray R, Singer D, Böhme D, Burz DS, Rai V, Hoffmann R, Shekhtman A. The receptor for advanced glycation end products (RAGE) specifically recognizes methylglyoxal-derived AGEs. Biochemistry 2014; 53:3327-35. [PMID: 24824951 PMCID: PMC4038343 DOI: 10.1021/bi500046t] [Citation(s) in RCA: 123] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022]
Abstract
Diabetes-induced hyperglycemia increases the extracellular concentration of methylglyoxal. Methylglyoxal-derived hydroimidazolones (MG-H) form advanced glycation end products (AGEs) that accumulate in the serum of diabetic patients. The binding of hydroimidozolones to the receptor for AGEs (RAGE) results in long-term complications of diabetes typified by vascular and neuronal injury. Here we show that binding of methylglyoxal-modified albumin to RAGE results in signal transduction. Chemically synthesized peptides containing hydroimidozolones bind specifically to the V domain of RAGE with nanomolar affinity. The solution structure of an MG-H1-V domain complex revealed that the hydroimidazolone moiety forms multiple contacts with a positively charged surface on the V domain. The high affinity and specificity of hydroimidozolones binding to the V domain of RAGE suggest that they are the primary AGE structures that give rise to AGEs-RAGE pathologies.
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Affiliation(s)
- Jing Xue
- Department of Chemistry, State University of New York at Albany , Albany, New York 12222, United States
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Wu J, Ma B, Wang Y, Zhang Y, Yan S, Castle SL. Lewis acid facilitated regioselective synthesis of τ-histidinoalanine. Tetrahedron Lett 2014. [DOI: 10.1016/j.tetlet.2014.04.008] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
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8
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Becker PM, Yu P. What makes protein indigestible from tissue-related, cellular, and molecular aspects? Mol Nutr Food Res 2013; 57:1695-707. [PMID: 23765989 DOI: 10.1002/mnfr.201200592] [Citation(s) in RCA: 37] [Impact Index Per Article: 3.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2012] [Revised: 02/20/2013] [Accepted: 02/21/2013] [Indexed: 11/08/2022]
Abstract
This paper gives an insight into key factors, which impair enzymatic protein digestion. By nature, some proteins in raw products are already poorly digestible because of structural peculiarities, or due to their occurrence in plant cytoplasmic organelles or in cell membranes. In plant-based protein, molecular and structural changes can be induced by genetic engineering, even if protein is not a target compound class of the genetic modification. Other proteins only become difficult to digest due to changes that occur during the processing of proteinaceous products, such as extruding, boiling, or acidic or alkaline treatment. The utilization of proteinaceous raw materials in industrial fermentations can also have negative impacts on protein digestibility, when reused as fermentation by-products for animal nutrition, such as brewers' grains. After consumption, protein digestion can be impeded in the intestine by the presence of antinutritional factors, which are ingested together with the food or feedstuff. It is concluded that the encircling matrix, but also molecular, chemical, and structural peculiarities or modifications to amino acids and proteins obstruct protein digestion by common proteolytic enzymes in humans and animals.
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Affiliation(s)
- Petra M Becker
- Wageningen UR Livestock Research, Lelystad, The Netherlands
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Wang T, Kartika R, Spiegel DA. Exploring post-translational arginine modification using chemically synthesized methylglyoxal hydroimidazolones. J Am Chem Soc 2012; 134:8958-67. [PMID: 22591136 PMCID: PMC3397831 DOI: 10.1021/ja301994d] [Citation(s) in RCA: 38] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/09/2023]
Abstract
The methylglyoxal-derived hydroimidazolones (MG-Hs) comprise the most prevalent class of non-enzymatic, post-translational modifications of protein arginine residues found in nature. These adducts form spontaneously in the human body, and are also present at high levels in the human diet. Despite numerous lines of evidence suggesting that MG-H-arginine adducts play critical roles in both healthy and disease physiology in humans, detailed studies of these molecules have been hindered by a lack of general synthetic strategies for their preparation in chemically homogeneous form, and on scales sufficient to enable detailed biochemical and cellular investigations. To address this limitation, we have developed efficient, multigram-scale syntheses of all MG-H-amino acid building blocks, suitably protected for solid-phase peptide synthesis, in 2-3 steps starting from inexpensive, readily available starting materials. Thus, MG-H derivatives were readily incorporated into oligopeptides site-specifically using standard solid-phase peptide synthesis. Access to synthetic MG-H-peptide adducts has enabled detailed investigations, which have revealed a series of novel and unexpected findings. First, one of the three MG-H isomers, MG-H3, was found to possess potent, pH-dependent antioxidant properties in biochemical and cellular assays intended to replicate redox processes that occur in vivo. Computational and mechanistic studies suggest that MG-H3-containing constructs are capable of participating in mechanistically distinct H-atom-transfer and single-electron-transfer oxidation processes. Notably, the product of MG-H3 oxidation was unexpectedly observed to disassemble into the fully unmodified arginine residue and pyruvate in aqueous solution. We believe these observations provide insight into the role(s) of MG-H-protein adducts in human physiology, and expect the synthetic reagents reported herein to enable investigations into non-enzymatic protein regulation at an unprecedented level of detail.
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Affiliation(s)
- Tina Wang
- Department of Chemistry, Yale University, 225 Prospect Street, New Haven, Connecticut 06511, USA
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11
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Taylor CM, De Silva ST. Synthesis of Histidinoalanine: A Comparison of β-Lactone and Sulfamidate Electrophiles. J Org Chem 2011; 76:5703-8. [DOI: 10.1021/jo200744d] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Affiliation(s)
- Carol M. Taylor
- Department of Chemistry, Louisiana State University, Baton Rouge, Louisiana 70803, United States
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12
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Calabrese MG, Mamone G, Caira S, Ferranti P, Addeo F. Quantitation of lysinoalanine in dairy products by liquid chromatography–mass spectrometry with selective ion monitoring. Food Chem 2009. [DOI: 10.1016/j.foodchem.2009.03.041] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
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14
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A convenient synthesis of some cross-linked amino acids and their diastereoisomeric characterization by nuclear magnetic resonance. Food Chem 2002. [DOI: 10.1016/s0308-8146(02)00103-6] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
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Friedman M. Chemistry, biochemistry, nutrition, and microbiology of lysinoalanine, lanthionine, and histidinoalanine in food and other proteins. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 1999; 47:1295-1319. [PMID: 10563973 DOI: 10.1021/jf981000+] [Citation(s) in RCA: 206] [Impact Index Per Article: 8.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Heat and alkali treatments of foods, widely used in food processing, result in the formation of dehydro and cross-linked amino acids such as dehydroalanine, methyldehydroalanine, beta-aminoalanine, lysinoalanine (LAL), ornithinoalanine, histidinoalanine (HAL), phenylethylaminoalanine, lanthionine (LAN), and methyl-lanthionine present in proteins and are frequently accompanied by concurrent racemization of L-amino acid isomers to D-analogues. The mechanism of LAL formation is a two-step process: first, hydroxide ion-catalyzed elimination of H(2)S from cystine and H(2)O, phosphate, and glycosidic moieties from serine residues to yield a dehydroalanine intermediate; second, reaction of the double bond of dehydroalanine with the epsilon-NH(2) group of lysine to form LAL. Analogous elimination-addition reactions are postulated to produce the other unusual amino acids. Processing conditions that favor these transformations include high pH, temperature, and exposure time. Factors that minimize LAL formation include the presence of SH-containing amino acids, sodium sulfite, ammonia, biogenic amines, ascorbic acid, citric acid, malic acid, and glucose; dephosphorylation of O-phosphoryl esters; and acylation of epsilon-NH(2) groups of lysine. The presence of LAL residues along a protein chain decreases digestibility and nutritional quality in rodents and primates but enhances nutritional quality in ruminants. LAL has a strong affinity for copper and other metal ions and is reported to induce enlargement of nuclei of rats and mice but not of primate kidney cells. LAL, LAN, and HAL also occur naturally in certain peptide and protein antibiotics (cinnamycin, duramycin, epidermin, nisin, and subtilin) and in body organs and tissues (aorta, bone, collagen, dentin, and eye cataracts), where their formation may be a function of the aging process. These findings are not only of theoretical interest but also have practical implications for nutrition, food safety, and health. Further research needs are suggested for each of these categories. These overlapping aspects are discussed in terms of general concepts for a better understanding of the impact of LAL and related compounds in the diet. Such an understanding can lead to improvement in food quality and safety, nutrition, microbiology, and human health.
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Affiliation(s)
- M Friedman
- Western Regional Research Center, Agricultural Research Service, U.S. Department of Agriculture, Albany, CA 94710, USA
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Boschin G, Scaglioni L, Arnoldi A. Optimization of the synthesis of the cross-linked amino acid ornithinoalanine and nuclear magnetic resonance characterization of lysinoalanine and ornithinoalanine. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 1999; 47:939-944. [PMID: 10552395 DOI: 10.1021/jf980869p] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Lysinoalanine (LAL) and ornithinoalanine (OAL) are unnatural amino acids that can be formed in food submitted to thermal treatment, especially in alkaline conditions. The paper presents an optimization of the synthetic procedure for the preparation of a standard of OAL that could be very useful to study the toxicological and nutritional consequences of the presence of OAL in food. In the meantime, it was possible to develop a method based on nuclear magnetic resonance for the diastereomeric characterization of LAL and OAL without derivatization. Interest in this method is based on the known differences in the nephrotoxicity of the two diastereisomers of LAL.
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Affiliation(s)
- G Boschin
- Dipartimento di Scienze Molecolari Agroalimentari, Sezione di Chimica, Università di Milano, via Celoria 2, I-20133 Milano, Italy
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