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Regio- and Stereospecific Analysis of Triacylglycerols—A Brief Overview of the Challenges and the Achievements. Symmetry (Basel) 2022. [DOI: 10.3390/sym14020247] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The efforts to reveal, in detail, the molecular and intramolecular structures of one of the main lipid classes, namely, triacyl-sn-glycerols, which are now known to affect their specific and important role in all living organisms, are briefly overviewed. Some milestones of significance in the gradual but continuous development and improvement of the analytical methodology to identify the triacylglycerol regio- and stereoisomers in complex lipid samples are traced throughout the years: the use of chromatography based on different separation principles; the improvements in the chromatographic technique; the development and use of different detection techniques; the attempts to simplify and automatize the analysis without losing the accuracy of identification. The spectacular recent achievements of two- and multidimensional methods used as tools in lipidomics are presented.
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2
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Kalpio M, Linderborg KM, Fabritius M, Kallio H, Yang B. Strategy for stereospecific characterization of natural triacylglycerols using multidimensional chromatography and mass spectrometry. J Chromatogr A 2021; 1641:461992. [PMID: 33706165 DOI: 10.1016/j.chroma.2021.461992] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2020] [Revised: 02/04/2021] [Accepted: 02/09/2021] [Indexed: 11/19/2022]
Abstract
Stereoisomeric determination of individual triacylglycerols (TAGs) in natural oils and fats is a challenge due to similar physicochemical properties of TAGs with different fatty acid combinations. In this study, we present a strategy to resolve the enantiomeric composition of nutritionally important TAGs in sea buckthorn (Hippophaë rhamnoides) as an example food matrix. The targeted strategy combines 1) fatty acid profiling with GC, 2) separation of TAGs with RP-HPLC, 3) stereospecific separation with chiral-phase HPLC and 4) structural characterization with MS. Three major asymmetric diacid- and triacid-TAG species were analyzed in sea buckthorn pulp oil. Off-line coupling of RP-HPLC and chiral-phase HPLC allowed separation of several TAG regioisomers and enantiomers, which could not be resolved using one-dimensional techniques. Enantiomeric ratios were determined and specific structural analysis of separated TAGs was performed using direct inlet ammonia negative ion chemical ionization method. Of the TAG 16:0/16:1/16:1 palmitic acid (C16:0) was located predominantly in a primary position and the enantiomeric ratio of TAG sn-16:1-16:1-16:0 to sn-16:0-16:1-16:1 was 70.5/29.5. Among the TAGs 16:0/16:0/18:2 and 16:0/16:0/16:1, only ca 5% had C16:0 in the sn-2 position, thus, ca 95% were symmetric sn-16:0-18:2-16:0 and sn-16:0-16:1-16:0. The enantiomeric ratio of triacid-TAGs containing C16:0 and two unsaturated fatty acids (palmitoleic C16:1, oleic C18:1 or linoleic acids C18:2) could not be resolved due to lack of commercial enantiopure reference compounds. However, it became clear that the targeted strategy presented offer unique and convenient method to study the enantiomeric structure of individual TAGs.
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Affiliation(s)
- Marika Kalpio
- Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turku, Finland.
| | - Kaisa M Linderborg
- Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turku, Finland
| | - Mikael Fabritius
- Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turku, Finland
| | - Heikki Kallio
- Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turku, Finland
| | - Baoru Yang
- Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turku, Finland
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Natwarlal Vadgama R, Anil A, Lali A. Identification of Glyceryl MonoRicinoleate (GMR) isomers using RP-HPLC and regio-specificity of lipases. Prep Biochem Biotechnol 2020; 50:401-407. [DOI: 10.1080/10826068.2019.1700519] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Affiliation(s)
| | - Annamma Anil
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, India
| | - Arvind Lali
- DBT-ICT Centre for Energy Biosciences, Institute of Chemical Technology, Mumbai, India
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Giuffrida F, Marmet C, Tavazzi I, Fontannaz P, Sauser J, Lee LY, Destaillats F. Quantification of 1,3-olein-2-palmitin (OPO) and Palmitic Acid in sn-2 Position of Triacylglycerols in Human Milk by Liquid Chromatography Coupled with Mass Spectrometry. Molecules 2018; 24:molecules24010022. [PMID: 30577597 PMCID: PMC6337272 DOI: 10.3390/molecules24010022] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2018] [Revised: 12/19/2018] [Accepted: 12/19/2018] [Indexed: 01/28/2023] Open
Abstract
This study describes the identification and quantification of fatty acids in the sn-2 position of triacylglycerols (TAG) and of the most abundant TAG regioisomers in human milk by liquid chromatography coupled with high-resolution mass spectrometry (HPLC-HRMS). Over 300 individual TAG species were observed and 1,3-olein-2-palmitin (OPO) was identified as the most abundant TAG regioisomer. Validation of the HPLC-HRMS method showed repeatability and intermediate reproducibility values ranging from 3.1 to 16.6% and 4.0 to 20.7%, respectively, and accuracy ranging from 75 to 97%. Results obtained by the HPLC-HRMS method were comparable to results from the ISO 6800 method for the quantification of palmitic acid in the sn-2 position of TAG (81.4 and 81.8 g 100 g−1 total palmitic acid, respectively). Processing the data obtained with the HPLC-HRMS method is extremely time consuming and, therefore, a targeted method suitable for the quantification of OPO in human milk samples by ultra-performance (UP) LC coupled with triple quadrupole (QQQ) MS was developed and validated. OPO identification and quantification by UPLC-QQQ were based on nominal mass and a fragmentation pattern obtained by multiple reaction monitoring experiments. The method was validated in terms of accuracy and precision by analyzing different aliquots of the same human milk sample over time and comparing the results with values obtained by HPLC-HRMS. Intermediate reproducibility was <15% and trueness comparable to HPLC-HRMS. Quantification of OPO in human milk samples collected at 30, 60 and 120 days postpartum showed that OPO content varies between 333 ± 11.8 and 383 ± 18.0 mg 100mL−1.
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Affiliation(s)
| | - Cynthia Marmet
- Nestlé Research, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland.
| | - Isabelle Tavazzi
- Nestlé Research, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland.
| | - Patric Fontannaz
- Nestlé Research, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland.
| | - Julien Sauser
- Nestlé Research, Vers-chez-les-Blanc, 1000 Lausanne 26, Switzerland.
| | - Le Ye Lee
- The Children's Medical Institute, National University Hospital, Singapore 637551, Singapore.
- Department of Pediatrics, Yong Loo Lin School of Medicine, National University of Singapore, Singapore 637551, Singapore.
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Sánchez DA, Tonetto GM, Ferreira ML. Screening of Lipases with Unusual High Activity in the sn-2 Esterification of 1,3-Dicaprin under Mild Operating Conditions. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2017; 65:5010-5017. [PMID: 28573851 DOI: 10.1021/acs.jafc.7b01327] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/07/2023]
Abstract
In this work, the synthesis of acylglycerides with high nutritional value was carried out by enzymatic esterification at sn-2 position of 1,3-dicaprin with palmitic acid. A comparative study of the performance of several biocatalysts according to the obtained products was carried out. The results obtained with several of the biocatalysts evaluated are very interesting, and it would be possible to use them to obtain a mixture of acylglycerides to act as a fat substitute. The final product was composed of about 90% of nutritionally attractive glycerides. These glycerides were medium-chain length triglycerides, medium-long chain triglycerides (mainly triglycerides with medium chain fatty acids at sn-1 and sn-3 positions and long chain fatty acid at sn-2 position), and 1,3-diglycerides. Pseudomonas fluorescens lipase and Burkholderia cepacia lipase immobilized on chitosan demonstrated unusual high activity in the sn-2 esterification of 1,3-dicaprin with palmitic acid at 45 °C and 12 h with 33% yield to 1,3-dicaproyl-2-palmitoyl glycerol. Burkholderia cepacia lipase has the advantage of being immobilized; however, BCL/chitosan has the advantages of being immobilized and therefore its easy recovery from the reaction media.
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Affiliation(s)
- Daniel Alberto Sánchez
- Planta Piloto de Ingeniería Química (PLAPIQUI), Universidad Nacional del Sur (UNS)-CONICET , Camino La Carrindanga Km 7, CC 717, 8000 Bahía Blanca, Argentina
| | - Gabriela Marta Tonetto
- Planta Piloto de Ingeniería Química (PLAPIQUI), Universidad Nacional del Sur (UNS)-CONICET , Camino La Carrindanga Km 7, CC 717, 8000 Bahía Blanca, Argentina
| | - María Luján Ferreira
- Planta Piloto de Ingeniería Química (PLAPIQUI), Universidad Nacional del Sur (UNS)-CONICET , Camino La Carrindanga Km 7, CC 717, 8000 Bahía Blanca, Argentina
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Triacylglycerol regioisomers in human milk resolved with an algorithmic novel electrospray ionization tandem mass spectrometry method. Food Chem 2017; 233:351-360. [PMID: 28530584 DOI: 10.1016/j.foodchem.2017.04.122] [Citation(s) in RCA: 67] [Impact Index Per Article: 9.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2016] [Revised: 03/16/2017] [Accepted: 04/19/2017] [Indexed: 11/23/2022]
Abstract
A highly sensitive mass spectrometric (MS) method was developed and validated to analyze ratios of regioisomeric triacylglycerols (TAGs) in fats and oils. UPLC resolution of lithiated TAGs followed by daughter scan MS/MS of positive ions revealed several indicative ions for quantitative analysis. Reference TAGs containing C14-C20 fatty acids (FAs) showed good linear response. Analysis of Finnish and Chinese pooled human milk samples revealed hundreds of regioisomeric TAGs. At least 64mol% of the TAGs were quantified with relative standard deviation <17%. When present in the same TAG molecule together with C18 FAs, palmitic acid was typically in the sn-2 position. When together with FAs 10:0, 12:0, 14:0, 20:1 and 20:2, the sn-2 preference of 16:0 was less clear. Oleic acid occupied typically the sn-1/sn-3 positions but when together with FAs 20:1, 20:2, 18:2, 14:1, 12:0 or 10:0 the positioning of 18:1 did not follow these rules.
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de la Fuente M, Juarez M. Revisión: Aplicación de las técnicas cromatográficas al estudio de triglicéridos y esteroles de la grasa de leche / Review: Application of chromatographic techniques to the study of triglycerides and sterols of milk fat. FOOD SCI TECHNOL INT 2016. [DOI: 10.1177/108201329900500201] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
The latest developments in analytical techniques, mainly chromatographic, for the study of triglycer ides (TG) and sterols in milk fat are revised. Gas chromatography (GC) with packed or short capillary columns has been used to separate TG according to their carbon numbers (CN) and can be applied to the detection of foreign fats in milk fat. Combined or hyphenated chromatographic techniques are indispensable in order to identify and quantify individual molecular species of TG: thin layer chro matography (TLC) or high performance liquid chromatography (HPLC) with Ag+ as prefraction stage, followed by supercritical fluid chromatography, GC with long capillary column, and HPLC with reverse phase and mass spectrometry as detector. These techniques, along with non-specific and/or specific hydrolysis procedures, have allowed a better knowledge of the positional distribution of the fatty acids within the molecules of TG. Concerning the study of the esterol fraction, the supression of the stages of fat extraction—separation of the insaponifiable and derivatization—previous to the analy sis by GC represents a considerable advance that should be in part attributed to the improvement of the chromatographic techniques.
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Affiliation(s)
- M.A. de la Fuente
- Departamento de Productos Lácteos. Instituto del frío (CSIC). Ciudad Universitaria s/n, 28040-Madrid España
| | - M. Juarez
- Departamento de Productos Lácteos. Instituto del frío (CSIC). Ciudad Universitaria s/n, 28040-Madrid España
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Šala M, Lísa M, Campbell JL, Holčapek M. Determination of triacylglycerol regioisomers using differential mobility spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2016; 30:256-264. [PMID: 27071217 DOI: 10.1002/rcm.7430] [Citation(s) in RCA: 39] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/05/2023]
Abstract
RATIONALE Triacylglycerols (TG) contain three fatty acyls attached to the glycerol backbone in stereochemically numbered positions sn-1, 2 and 3. Isobaric TG with exchanged fatty acyl chains in positions sn-1/3 vs. sn-2 are referred to as regioisomers and the determination of their regioisomeric ratios is important for nutrition purposes. METHODS Differential mobility spectrometry (DMS) coupled to electrospray ionization mass spectrometry (ESI-MS) is applied for the separation of simple unsaturated TG regioisomers extracted from porcine adipose tissue using their silver-ion molecular adducts. RESULTS Four pairs of TG regioisomers containing combinations of unsaturated and saturated fatty acyl chains are successfully separated using DMS with 1-butanol or 1-propanol as the chemical modifier. Various experimental parameters are carefully optimized, such as the separation and compensation voltages applied to DMS electrodes, the type and flow rate of chemical modifier and the dwell time of analyte ions in the DMS cell. The optimized DMS approach is used for the characterization of TG regioisomers in less than one minute, compared to tens of minutes typical for silver-ion or reversed-phase high-performance liquid chromatography/mass spectrometry approaches. CONCLUSIONS The application of this method for the characterization of TG regioisomers in porcine adipose tissue shows the method suitability for analyses of other animal fats.
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Nguyen T, Aparicio M, Saleh MA. Accurate Mass GC/LC-Quadrupole Time of Flight Mass Spectrometry Analysis of Fatty Acids and Triacylglycerols of Spicy Fruits from the Apiaceae Family. Molecules 2015; 20:21421-32. [PMID: 26633337 PMCID: PMC4881421 DOI: 10.3390/molecules201219779] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/03/2015] [Revised: 11/23/2015] [Accepted: 11/26/2015] [Indexed: 11/16/2022] Open
Abstract
The triacylglycerol (TAG) structure and the regio-stereospecific distribution of fatty acids (FA) of seed oils from most of the Apiaceae family are not well documented. The TAG structure ultimately determines the final physical properties of the oils and the position of FAs in the TAG molecule affects the digestion; absorption and metabolism; and physical and technological properties of TAGs. Fixed oils from the fruits of dill (Anethum graveolens), caraway (Carum carvi), cumin (Cuminum cyminum), coriander (Coriandrum sativum), anise (Pimpinella anisum), carrot (Daucus carota), celery (Apium graveolens), fennel (Foeniculum vulgare), and Khella (Ammi visnaga), all from the Apiaceae family, were extracted at room temperature in chloroform/methanol (2:1 v/v) using percolators. Crude lipids were fractionated by solid phase extraction to separate neutral triacylglycerols (TAGs) from other lipids components. Neutral TAGs were subjected to transesterification process to convert them to their corresponding fatty acids methyl esters (FAMES) using 1% boron trifluoride (BF₃) in methanol. FAMES were analyzed by gas chromatography-quadrupole time of flight (GC-QTOF) mass spectrometry. Triglycerides were analyzed using high performance liquid chromatography-quadrupole time of flight (LC-QTOF) mass spectrometry. Petroselinic acid was the major fatty acid in all samples ranging from 57% of the total fatty acids in caraway up to 82% in fennel. All samples contained palmitic (16:0), palmitoleic (C16:1n-9), stearic (C18:0), petroselinic (C18:1n-12), linoleic (C18:2n-6), linolinic (18:3n-3), and arachidic (C20:0) acids. TAG were analyzed using LC-QTOF for accurate mass identification and mass spectrometry/mass spectrometry (MS/MS) techniques for regiospesific elucidation of the identified TAGs. Five major TAGs were detected in all samples but with different relative concentrations in all of the tested samples. Several other TAGs were detected as minor components and were present in some samples and absence in the others. Regiospecific analysis showed a non-random fatty acids distribution. Petroselinic acid was predominantly located at the sn-1 and sn-3 positions.
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Affiliation(s)
- Thao Nguyen
- Department of Chemistry, Texas Southern University, Houston, TX 77004, USA.
| | - Mario Aparicio
- Agilent Technologies, Inc., 3750 Brookside Parkway, Suite 100, Alpharetta, GA 30022, USA.
| | - Mahmoud A Saleh
- Department of Chemistry, Texas Southern University, Houston, TX 77004, USA.
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Ten-Doménech I, Beltrán-Iturat E, Herrero-Martínez JM, Sancho-Llopis JV, Simó-Alfonso EF. Triacylglycerol Analysis in Human Milk and Other Mammalian Species: Small-Scale Sample Preparation, Characterization, and Statistical Classification Using HPLC-ELSD Profiles. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2015; 63:5761-5770. [PMID: 26028153 DOI: 10.1021/acs.jafc.5b01158] [Citation(s) in RCA: 24] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/04/2023]
Abstract
In this work, a method for the separation of triacylglycerols (TAGs) present in human milk and from other mammalian species by reversed-phase high-performance liquid chromatography using a core-shell particle packed column with UV and evaporative light-scattering detectors is described. Under optimal conditions, a mobile phase containing acetonitrile/n-pentanol at 10 °C gave an excellent resolution among more than 50 TAG peaks. A small-scale method for fat extraction in these milks (particularly of interest for human milk samples) using minimal amounts of sample and reagents was also developed. The proposed extraction protocol and the traditional method were compared, giving similar results, with respect to the total fat and relative TAG contents. Finally, a statistical study based on linear discriminant analysis on the TAG composition of different types of milks (human, cow, sheep, and goat) was carried out to differentiate the samples according to their mammalian origin.
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Affiliation(s)
- Isabel Ten-Doménech
- †Department of Analytical Chemistry, Faculty of Chemistry, University of Valencia, C. Dr. Moliner 50, E-46100 Burjassot, Valencia, Spain
| | - Eduardo Beltrán-Iturat
- §Research Institute for Pesticides and Water, University Jaume I, E-12071 Castellón, Spain
| | - José Manuel Herrero-Martínez
- †Department of Analytical Chemistry, Faculty of Chemistry, University of Valencia, C. Dr. Moliner 50, E-46100 Burjassot, Valencia, Spain
| | | | - Ernesto Francisco Simó-Alfonso
- †Department of Analytical Chemistry, Faculty of Chemistry, University of Valencia, C. Dr. Moliner 50, E-46100 Burjassot, Valencia, Spain
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Linderborg KM, Kalpio M, Mäkelä J, Niinikoski H, Kallio HP, Lagström H. Tandem mass spectrometric analysis of human milk triacylglycerols from normal weight and overweight mothers on different diets. Food Chem 2013; 146:583-90. [PMID: 24176384 DOI: 10.1016/j.foodchem.2013.09.092] [Citation(s) in RCA: 36] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/19/2013] [Revised: 09/12/2013] [Accepted: 09/16/2013] [Indexed: 11/24/2022]
Abstract
The composition and structures of TAGs in the human milk from mothers with different food choices and prepregnancy body mass index were determined with two tandem mass spectrometric methods (negative APCI-MS/MS and positive UHPLC/ESI-MS/MS) at the infant's age of three months. The normal weight mothers with recommended food choices had more 18:3n-3 and less 18:0 in their milk than normal weight mothers with non-recommended food choices. A significant difference between the normal weight mothers on the non-recommended food choices and the other groups was seen in acyl carbon number: number of double bond (ACN:DB)-groups 54:6, 54:5, 54:3 and 54:2. In ACN:DB 52:7 and 52:6 the two recommended food choices-groups differed significantly from the two non-recommended food choices-groups. The regioisomerism of TAGs varied little despite differences in mother's weight and diet with sn-18:1-16:0-18:1 as the most prevalent regioisomer in the milk (13.8±2.7%). The results of this study highlight the importance of structure specific human milk substitutes and the careful selection of the MS/MS methods for analysis of mixtures of several isobaric TAGs.
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Affiliation(s)
- Kaisa M Linderborg
- Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland.
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Kalo PJ, Kemppinen A. Regiospecific analysis of TAGs using chromatography, MS, and chromatography-MS. EUR J LIPID SCI TECH 2012. [DOI: 10.1002/ejlt.201100367] [Citation(s) in RCA: 12] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
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Chiofalo B, Dugo P, Bonaccorsi IL, Mondello L. Comparison of major lipid components in human and donkey milk: new perspectives for a hypoallergenic diet in humans. Immunopharmacol Immunotoxicol 2011; 33:633-44. [DOI: 10.3109/08923973.2011.555409] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Leskinen HM, Suomela JP, Kallio HP. Quantification of triacylglycerol regioisomers by ultra-high-performance liquid chromatography and ammonia negative ion atmospheric pressure chemical ionization tandem mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2010; 24:1-5. [PMID: 19957298 DOI: 10.1002/rcm.4346] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/28/2023]
Abstract
The regioisomer composition of triacylglycerols (TAGs) in various vegetable oils was determined with a new liquid chromatography/tandem mass spectrometry (LC/MS/MS method). A direct inlet ammonia negative ion chemical ionization (NICI) MS/MS method was improved by adapting it to LC negative ion (NI) atmospheric pressure chemical ionization (APCI) MS/MS system using ammonia as nebulizer gas. The method is based on the preferential formation of [M-H-RCOOH-100](-) ions during collision-induced dissociation by loss of sn-1/3 fatty acids from [M-H](-) ions. Calibration curves were created from nine reference TAGs: Ala/L/L, Gla/L/L, L/L/O, L/O/O, P/O/O, P/P/O, Po/Po/V, Po/Po/O, and C/O/O. The calibration curves were used to quantify the regioisomer compositions of selected TAGs in rapeseed oil, sunflower seed oil, palm oil, black currant seed oil, and sea buckthorn pulp oil. The method discriminates the different regioisomers and the results obtained by this method were in good agreement with previous results. This proves that this new method can be used for the determination of regiospecific distribution of fatty acids in TAGs.
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Affiliation(s)
- Heidi M Leskinen
- Department of Biochemistry and Food Chemistry, University of Turku, FI-20014 Turku, Finland.
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Guncheva M, Zhiryakova D, Radchenkova N, Kambourova M. Acidolysis of Tripalmitin with Oleic Acid Catalyzed by a Newly Isolated Thermostable Lipase. J AM OIL CHEM SOC 2007. [DOI: 10.1007/s11746-007-1175-9] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022]
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17
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Leskinen H, Suomela JP, Kallio H. Quantification of triacylglycerol regioisomers in oils and fat using different mass spectrometric and liquid chromatographic methods. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2007; 21:2361-73. [PMID: 17590869 DOI: 10.1002/rcm.3090] [Citation(s) in RCA: 81] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/16/2023]
Abstract
The regioisomers (sn-ABA/sn-AAB) of four triacylglycerols (TAGs), 18:2/18:2/18:1 (LLO), 18:2/18:1/18:1 (LOO), 16:0/18:1/18:1 (POO), and 16:0/16:0/18:1 (PPO), were quantified in lard, rapeseed oil, and sunflower seed oil by three different mass spectrometric methods using liquid chromatography (LC) and two different mass spectrometers. The ionization methods used were positive ion atmospheric pressure chemical ionization (APCI), positive ion electrospray ionization (ESI), and negative ion chemical ionization (NICI) with ammonia as the reagent gas. The LC/APCI-MS results with two different instrumentation types, LC/ESI-MS/MS and direct inlet ammonia NICI-MS/MS, were compared. The LC/APCI-MS method is based on the preferential formation of diacylglycerol (DAG) fragment ions during ionization by loss of sn-1/3 fatty acids from [M+H]+ ions. Similar formation of the DAG ions from [M+NH4]+ ions by collision-induced dissociation (CID) in the LC/ESI-MS/MS method and the [M-H--RCOOH-100]- ions from [M-H]- ions by CID in the direct inlet ammonia NICI-MS/MS method is observed. These methods were found to be useful and reliable in determining the regioisomeric structure of TAGs. No statistically significant differences were found between the results obtained with these methods. For LLO, LOO, and POO the proportions of sn-ABA isomer calculated from the results from all four methods were in rapeseed oil 7.7 +/- 6.5, 57.9 +/- 3.3, and 4.5 +/- 6.1%, respectively, and in sunflower seed oil 12.2 +/- 6.9, 34.0 +/- 5.2, and 1.4 +/- 2.8%, respectively. The proportions of ABA of POO and PPO in lard were 95.3 +/- 3.2 and 4.9 +/- 5.6%, respectively. This study also proved that the LC/APCI-MS/MS method examined is not applicable in the quantification of TAG regioisomers because the formation of DAG ions is not clearly dependent on the positional distribution of the fatty acids.
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Affiliation(s)
- Heidi Leskinen
- Department of Biochemistry and Food Chemistry, University of Turku, Vatselankatu 2, Turku 20014, Finland
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Kemppinen A, Kalo P. Quantification of triacylglycerols in butterfat by gas chromatography-electron impact mass spectrometry using molar correction factors for [M-RCOO]+ ions. J Chromatogr A 2006; 1134:260-83. [PMID: 16996071 DOI: 10.1016/j.chroma.2006.08.089] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2006] [Revised: 08/28/2006] [Accepted: 08/30/2006] [Indexed: 11/27/2022]
Abstract
A quantitative electron impact GC-MS method using molar correction factors (MCFs) for [M-RCOO]+ ions has been developed for determination of molecular species of triacylglycerols (TAGs). MCFs were determined by linear calibration for 226 ions of 104 TAG species with good reproducibility: on the average, coefficient of determination was 0.975 +/- 0.043 and 0.963 +/- 0.115 for saturated and unsaturated TAGs, respectively. The MCFs of the sn-1(3) regioisomers of short-chain TAGs were lower than those of sn-2 isomers indicating ca. 2-3-fold higher cleavage of butyroyl and caproyl groups from the primary positions than from the secondary position. The method enabled quantification of 139 and 135 individual TAG species of butterfat (BF) and interesterified butterfat, respectively, including several regioisomers of short-chain TAGs. The most abundant molecular species of the even-numbered TAGs in BF were butyroylpalmitoyloleoylglycerol (5.05 mol%), butyroyldipalmitoylglycerol (4.75 mol%), and palmitoyldioleoylglycerol (3.32 mol%). The method provides an alternative for elucidation of nutritional and technological properties of relatively saturated TAG mixtures.
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Affiliation(s)
- Asmo Kemppinen
- Department of Food Technology, FI-00014 University of Helsinki, Helsinki, Finland.
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19
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The regiospecific position of 18∶1cisandtransmonoenoic fatty acids in milk fat triacylglycerols. J AM OIL CHEM SOC 2006. [DOI: 10.1007/s11746-006-1219-6] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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20
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Yang B, Kallio H. Analysis of triacylglycerols of seeds and berries of sea buckthorn (Hippophaë rhamnoides) of different origins by mass spectrometry and tandem mass spectrometry. Lipids 2006; 41:381-92. [PMID: 16808152 DOI: 10.1007/s11745-006-5109-3] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
TAG of seeds, berries, and fruit pulp/peel of different subspecies of sea buckthorn (Hippophaë rhamnoides) were analyzed by MS and tandem mass spectrometry (MS/MS). The seeds contained mainly TAG with acyl carbon number (ACN) of 52 with 2-6 double bonds (DB) (20-30%), and TAG of ACN 54 with 3-9 DB (70-80%). In the pulp/peel fraction, the major TAG were species with ACN:DB of 48:1 to 48:3 (19-49%), 50:1 to 50:4 (31-41%), and 52:1 to 52:6 (9-19%). The molecular weight species of whole berries largely resembled those of fruit pulp/peel with additional species of ACN 54 from the seeds (5-24%). Subspecies (ssp.) sinensis differed from ssp. mongolica and rhamnoides by having a higher proportion of TAG of ACN 52 (27% vs. 21% and 22%, P< 0.05) and a lower proportion of ACN 54 (71% vs. 79% and 78%, P < 0.01) in seed TAG. Seed TAG of ssp. mongolica contained a higher proportion of more unsaturated species compared with those of the two other subspecies. Berry TAG of ssp. mongolica had the highest proportion of molecular species of ACN 48 due to the higher proportion of palmitic and palmitoleic acids and the lower seed content of the berries. Overall, palmitic acid favored the sn-1 and sn-3 positions. The order of preference of unsaturated FA for the sn-2 position depended at least partially on the FA combination of TAG. Seed TAG of ssp. mongolica contained a higher proportion of alpha-linolenic acid in the sn-2 position than those of ssp. sinensis. In berry TAG, ssp. mongolica had the highest proportions of palmitoleic and linoleic acids in the sn-2 position, and the lowest proportion of oleic/cis-vaccenic acid in the sn-2 position, among the three subspecies.
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Affiliation(s)
- Baoru Yang
- Department of Biochemistry and Food Chemistry, University of Turku, Finland.
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21
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Dugo P, Kumm T, Fazio A, Dugo G, Mondello L. Determination of beef tallow in lard through a multidimensional off-line non-aqueous reversed phase–argentation LC method coupled to mass spectrometry. J Sep Sci 2006; 29:567-75. [PMID: 16583695 DOI: 10.1002/jssc.200500342] [Citation(s) in RCA: 30] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
The presence of tallow in lard is not easy to determine, due to the similarity of the composition of these two animal fats, which differ mainly in the distribution of fatty acids (FA) in the three positions of the glycerol molecule. The determination of the composition of the triacylglycerol (TAG) fraction of lard, tallow, and their mixtures was investigated by HPLC in combination with atmospheric pressure chemical ionization mass spectrometry (APCI-MS). The presence of tallow in lard was determined through the study of the sn-POP/sn-PPO ratio by multidimensional HPLC. The off-line bidimensional system was attained through the coupling of non-aqueous reversed phase (NARP)-HPLC and silver ion (Ag)-HPLC. The primary column eluate was fractionated and the fraction containing POP/PPO isomers was injected onto the secondary column, allowing the separation of positional isomers, unresolved in the first dimension. Peak assignment was carried out by combining retention data with APCI-MS spectral information. The fatty acid distribution along the glycerol backbone, determined by Ag-HPLC, was confirmed through diglyceride ion ratios derived from APCI-MS analysis. Method validation was carried out in preliminary applications on standard TAGs. The analytical results obtained show that even a 5% addition of tallow to lard modifies the distribution of positional isomers.
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Affiliation(s)
- Paola Dugo
- Dipartimento di Chimica Organica e Biologica, Facoltà di Scienze SS.NN.FF., University of Messina, Messina, Italy
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22
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Cvacka J, Krafková E, Jiros P, Valterová I. Computer-assisted interpretation of atmospheric pressure chemical ionization mass spectra of triacylglycerols. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2006; 20:3586-94. [PMID: 17091535 DOI: 10.1002/rcm.2770] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/12/2023]
Abstract
Current lipidomics approaches require simple and rapid algorithms enabling the interpretation of mass spectra of lipids. Most lipids are complex mixtures of related components in which the composition of the aliphatic fatty acid chains varies from one molecule to the next. Triacylglycerols (TAGs) are an example of such a lipid class. Fatty acid chains are the only parts of the molecule to change from one species to another. Fatty acids, and consequently also TAGs, can be characterized by two parameters; the number of carbon atoms and the number of double bonds. All calculations reflecting relations among ions in the spectra can be easily made using these parameters. An algorithm for the automated interpretation of TAGs from atmospheric pressure chemical ionization mass spectra (TriglyAPCI) is presented in this paper. The algorithm first identifies diacylglycerol fragments and molecular adducts. In the next step, relations among the ions are searched and possible TAG structures are suggested. Individual features of the algorithm are described in detail and the software performance is demonstrated for the liquid chromatography/mass spectrometric (LC/MS) analysis of TAGs isolated from the termite Prorhinotermes canalifrons.
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Affiliation(s)
- Josef Cvacka
- Institute of Organic Chemistry and Biochemistry, Academy of Sciences of the Czech Republic, Flemingovo námestí 2, 166 10 Prague 6, Czech Republic.
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23
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Kalo P, Kemppinen A, Ollilainen V, Kuksis A. Regiospecific determination of short-chain triacylglycerols in butterfat by normal-phase HPLC with on-line electrospray-tandem mass spectrometry. Lipids 2005; 39:915-28. [PMID: 15669768 DOI: 10.1007/s11745-004-1314-3] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
This study uses normal-phase HPLC with on-line positive ion electrospray mass spectrometry (ESI-MS) to obtain quantitative compositional data on both synthetic and butterfat short-chain TAG. The product ion tandem MS of standards averaged 11.1 times lower in abundance of the ion formed by cleavage of FA from the sn-2-position for the pairs of regioisomers in the TAG classes: L/L/S-L/S/L and L/S/S-S/L/S, where L denotes long and S short acyl chain (C2-C6). The molar correction factors, determined for 42 regioisomeric pairs of short-chain TAG of 20 randomized mixture of standards, differed by 1.4-80% as the ratios varied between 0.217 and 5.847. Butterfat TAG were resolved into four fractions on short flash chromatography grade silica gel columns. Pairs of regioisomers in the TAG classes L/S/S-S/L/S with predominance of L/S/S isomers and the sole regioisomers in the TAG classes L/L(M)/S were identified by tandem MS, where M denotes either 8:0 or 10:0 acyl chain. The total proportion of L/L(M)/S isomers was estimated at 34.7 and that of L/S/S-S/L/S at 1.0 mol%, including a small proportion of S/S/S. In contrast to previous work, the present data indicate the presence of a small proportion of butyric and caproic acids in the sn-1-position. The overall distribution of the FA in the short-chain TAG of butterfat, calculated from direct MS measurements, was consistent with the results of indirect determinations based on stereospecific analyses of total butterfat.
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Affiliation(s)
- P Kalo
- Department of Applied Chemistry and Microbiology, University of Helsinki, Helsinki, Finland.
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24
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Yli-Jokipii KM, Schwab US, Tahvonen RL, Xu X, Mu H, Kallio HPT. Positional distribution of decanoic acid: effect on chylomicron and VLDL TAG structures and postprandial lipemia. Lipids 2005; 39:373-81. [PMID: 15357025 DOI: 10.1007/s11745-004-1241-3] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
Abstract
Although medium-chain FA (MCFA) are mainly absorbed via the portal venous system, they are also incorporated into chylomicron TAG; therefore, the positional distribution of MCFA in TAG is likely to affect their metabolic fate. We studied chylomicron and VLDL TAG structures, as well as the magnitude of postprandial lipemia, after two oral fat loads containing decanoic acid (10:0) predominantly at the sn-1(3),2 (MML) or at the sn-1,3 positions (MLM) of TAG in a randomized, double-blind, crossover clinical trial with 10 healthy, normal-weight volunteers. An MS-MS method was used to analyze TAG regioisomers. The position of decanoic acid in chylomicron TAG reflected its position in the TAG ingested, and TAG with none, one, two, or three decanoic acid residues were detected after ingestion of both fats. More (P < 0.05) 30:0 and 38:1 TAG (acyl carbons:double bonds) and fewer 46:5, 54:5, and 54:4 TAG were found in chylomicrons after ingestion of MML than after MLM. The VLDL TAG composition did not differ between the fat loads but did change (P < 0.05) 2 to 6 h after ingestion of both fats. No statistical differences were seen between the fat loads in areas under the plasma, chylomicron, or VLDL TAG response curves or in FFA concentrations. Thus, the positional distribution of MCFA in TAG affects their metabolic fate, but the magnitude of postprandial lipemia does not seem to be dependent on the positional distribution of MCFA in the ingested fat.
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Affiliation(s)
- Kaisa M Yli-Jokipii
- Department of Biochemistry and Food Chemistry, University of Turku, Turku, Finland.
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25
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Linderborg (née Yli-Jokipii) KM, Kallio HPT. Triacylglycerol Fatty Acid Positional Distribution and Postprandial Lipid Metabolism. FOOD REVIEWS INTERNATIONAL 2005. [DOI: 10.1080/fri-200061623] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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26
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Kuksis A, Itabashi Y. Regio- and stereospecific analysis of glycerolipids. Methods 2005; 36:172-85. [PMID: 15896980 DOI: 10.1016/j.ymeth.2004.11.001] [Citation(s) in RCA: 21] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2004] [Revised: 11/15/2004] [Accepted: 11/15/2004] [Indexed: 10/25/2022] Open
Abstract
In recent years researchers have recognized the potential value of comprehensive lipid profiling (lipidomics), which was invented and promoted by lipidologists who recognized the many valuable applications that grew out of the fields of DNA profiling (genomics) and protein profiling (proteonomics). Through lipid class-selective intrasource ionization and subsequent analysis of two-dimensional cross-peak intensities, the chemical identity and mass composition of individual molecular species of most lipid classes can now be determined in a chloroform extract. There remains, however, the necessity to distinguish the enantiomers and isobaric regioisomers resulting from enzymatic and chemical reactions, which conventional high performance liquid chromatography/mass spectrometry (HPLC/MS) has been slow to accommodate, and tandem MS unable to provide. While reversed-phase HPLC can separate regioisomers, normal-phase HPLC can resolve diastereomers, and chiral-phase HPLC can effect dramatic resolution of enantiomers, the full potential of the combined systems has seldom been exploited. The present chapter calls attention to both recent and earlier combinations of these methodologies with mass spectrometry, which allows the HPLC/ESI (electrospray ionization)-MS/MS separation and identification of enantiomeric diacylglycerols, triacylglycerols, and glycerophospholipids as well as their isobaric regioisomers. These developments permit further expansion of lipid profiling (lipidomics) and better understanding of lipid metabolism.
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Affiliation(s)
- Arnis Kuksis
- Banting and Best Department of Medical Research, University of Toronto, Toronto, Canada M5G 1L6.
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27
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Dugo P, Kumm T, Lo Presti M, Chiofalo B, Salimei E, Fazio A, Cotroneo A, Mondello L. Determination of triacylglycerols in donkey milk by using high performance liquid chromatography coupled with atmospheric pressure chemical ionization mass spectrometry. J Sep Sci 2005; 28:1023-30. [PMID: 16013829 DOI: 10.1002/jssc.200500025] [Citation(s) in RCA: 35] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022]
Abstract
The separation and determination of triacylglycerols (TAGs), which are the main components of naturally occurring fats and oils, in milk fat is a challenging task due to the very complex nature of this matrix. In the present study the TAG fraction of donkey milk lipids has been characterized by using high performance liquid chromatography-atmospheric pressure chemical ionization mass spectrometry (HPLC-APCI-MS). HPLC in reversed phase mode has been used for TAG separation and silver ion (Ag+) HPLC has been used as a second dimension to clarify and confirm the identification. The RP-HPLC eluate was fractionated and the fractions of interest were injected onto the Ag+-HPLC column. In both cases peak assignment was carried out by combining retention data with APCI-MS spectra information. In total, 55 TAGs in donkey milk fat were identified (without considering the positional isomers) and quantified on the basis of percentage peak areas in the RP-HPLC chromatogram (without the use of correction factors). Amongst the identified triacylglycerols, POLn, POO, PPO, CaPO, POL, and PPoO proved to be the main components of the TAG fraction of donkey milk.
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Affiliation(s)
- Paola Dugo
- Dipartimento di Chimica Organica e Biologica, Facoltà di Scienze, Università di Messina, 98166 Messina, Italy
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28
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Kallio H, Tuomasjukka S, Johansson A, Tahvonen R, Nieminen N, Sjövall O, Kurvinen JP, Kivini H. Analysis of regioisomers of triacylglycerols of northern currant seed oil by tandem mass spectrometry. EUR J LIPID SCI TECH 2005. [DOI: 10.1002/ejlt.200401037] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/05/2022]
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29
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Morera S, Castellote AI, Jauregui O, Casals I, López-Sabater MC. Triacylglycerol markers of mature human milk. Eur J Clin Nutr 2004; 57:1621-6. [PMID: 14647228 DOI: 10.1038/sj.ejcn.1601733] [Citation(s) in RCA: 44] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
Abstract
OBJECTIVES To determine which triacylglycerol (TAG) species in mature human milk are less affected by external factors and may thus be considered as TAG markers, as well as to determine which species are most influenced by these external conditions. Furthermore, we examine the correlation between the TAG markers and their fatty acids (FAs). SETTING AND SUBJECTS Six healthy women from Barcelona (Catalonia, Spain). DESIGN AND INTERVENTIONS In order to obtain the maximum variability of sampling conditions, 40 mature human milk samples were collected from different mothers, on different days, at different times of the day, and from different breasts during and after both the baby's and mother's meal. TAG and FA profiles were determined and correlated. The TAG composition was determined by high-performance liquid chromatography with an evaporative light-scattering detector, and also with atmospheric pressure chemical ionisation mass spectrometry. FAs compositions were determined by gas chromatography. RESULTS The results were analysed using the SPSS statistical package and proved to be more variable than might have been found in a more restrictive sample design. Nevertheless, despite these conditions, some TAG species were found in relatively constant levels in mature human milk, and could thus be considered as markers of the mature milk TAG profile. TAG species that we can classify in this group were: LaMO, CaPO, LaCaO, LaPCa, LaOL, MPLn, LLO, LaOO, MPL, and MOL. The names do not indicate the location of fatty acids in the glycerol molecule. On the other hand, concentrations of other TAG species vary considerably between samples and consequently these may be understood to be especially affected by the external factors. TAGs like PaLS, MPO, PaOO, PPP, MPS, SPP, LOO, PPO, MOS, SSP, POL, and SOS are in this second group. Correlation between the TAG markers and their FAs was examined by Pearson's test and a significant correlation was found for some FAs. CONCLUSIONS The TAG species present in mature human milk are affected in different ways by external factors such as dietary intake, nutritional status, length of lactation, time of the day, etc. Some TAGs may be considered as markers of mature human milk as they are relatively constant under a wide range of sampling conditions and do not depend on the factors mentioned. SPONSORSHIP This study was supported by the Fundació Mestres Jané.
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Affiliation(s)
- S Morera
- Dpt. Nutrició i Bromatología, Facultat de Farmàcia, Centre de Referència en Tecnologia dels Aliments (CeRTA), Universitat de Barcelona, Avda. Joan XXIII s/n, 08028 Barcelona, Spain
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30
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Yli-Jokipii KM, Schwab US, Tahvonen RL, Kurvinen JP, Mykkänen HM, Kallio HPT. Chylomicron and VLDL TAG structures and postprandial lipid response induced by lard and modified lard. Lipids 2004; 38:693-703. [PMID: 14506832 DOI: 10.1007/s11745-003-1117-6] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
Alterations in chylomicron and VLDL TAG and the magnitude of postprandial lipemia were studied in healthy volunteers after two meals of equal FA composition but different TAG FA positional distribution. Molecular level information of individual lipoprotein TAG regioisomers was obtained with a tandem MS method. The incremental area under the response curve of VLDL TAG was larger (P = 0.021) after modified lard than after lard. In plasma TAG, the difference did not quite reach statistical significance (P = 0.086). In general, there were less TAG with palmitic acid in the sn-2 position and more TAG with oleic acid in the sn-2 position in chylomicrons than in fat ingested. From 1.5 to 8 h postprandially, the proportion of individual chylomicron TAG was constant or influenced by TAG M.W. VLDL TAG regioisomerism was similar regardless of the positional distribution of fat ingested. Significant alterations were seen in VLDL TAG FA, in M.W. fractions, and in individual regioisomers with respect to time. The TAG sn-14:0-18:1-18:1 + sn-18:1-18:1-14:0, sn-16:0-16:1-18:1 + sn-18:1-16:1-16:0, and sn-16:1-18:1-18:1 + sn-18:1-18:1-16:1 decreased (P < 0.05); and sn-16:0-16:0-18:2 + sn-18:2-16:0-16:0, sn-16:0-16:0-18:1 + sn-18:1-16:0-16:0, sn-16:0-18:1-16:0, and sn-16:0-18:1-18:2 + sn-18:2-18:1-16:0 increased (P < 0.05) after both meals. In conclusion, positional distribution of TAG FA was found to affect postprandial lipid metabolism in healthy normolipidemic subjects.
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Affiliation(s)
- Kaisa M Yli-Jokipii
- Department of Biochemistry and Food Chemistry, University of Turku, Finland.
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31
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Structural characterization of triacylglycerols using electrospray ionization-MSnion-trap MS. J AM OIL CHEM SOC 2003. [DOI: 10.1007/s11746-003-0676-2] [Citation(s) in RCA: 36] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
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32
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Kurvinen JP, Sjövall O, Tahvonen R, Anklam E, Kallio H. Rapid MS method for analysis of cocoa butter TAG. J AM OIL CHEM SOC 2002. [DOI: 10.1007/s11746-002-0534-2] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Affiliation(s)
- J. -P. Kurvinen
- ; Department of Biochemistry and Food Chemistry; University of Turku; FIN-20014 Turku Finland
| | - O. Sjövall
- ; Department of Biochemistry and Food Chemistry; University of Turku; FIN-20014 Turku Finland
| | - R. Tahvonen
- ; Department of Biochemistry and Food Chemistry; University of Turku; FIN-20014 Turku Finland
| | - E. Anklam
- ; DG Joint Research Centre, Institute for Health and Consumer Protection, Food Products Unit; European Commission; I-21020 Ispra (VA) Italy
| | - H. Kallio
- ; Department of Biochemistry and Food Chemistry; University of Turku; FIN-20014 Turku Finland
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33
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Yli-Jokipii KM, Schwab US, Tahvonen RL, Kurvinen JP, Mykkänen HM, Kallio HPT. Triacylglycerol molecular weight and to a lesser extent, fatty acid positional distribution, affect chylomicron triacylglycerol composition in women. J Nutr 2002; 132:924-9. [PMID: 11983815 DOI: 10.1093/jn/132.5.924] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Postprandial composition of chylomicron triacylglycerols (TAG) and their clearance may be affected by the molecular weight of TAG, their fatty acid (FA) combinations and the positional distribution of FA in TAG. Delayed postprandial TAG clearance is a risk factor for cardiovascular disease. However, due to the complexity of traditional analysis methods, the composition of individual TAG molecules is frequently overlooked. In this study, chylomicron TAG molecular weight distribution and regioisomerism were followed in 10 healthy female volunteers after two fat loads with identical FA composition but different positional distributions (palm oil and transesterified palm oil). An efficient tandem mass spectrometric method of analysis was applied. During the 6-h observation period, the relative concentrations of TAG with 48:2 [48 acyl carbons and 2 double bonds (ACN:DB)], 50:3 and 50:2 decreased, whereas the proportions of 48:0 (tripalmitin), 52:3 and 54:4 remained constant and the proportion of 54:3 (triolein) increased (P < 0.05). The existence of seven regioisomers containing palmitic, oleic and linoleic acids in different sn-positions was studied. The amount of 1,3-dipalmitoyl-2-oleoyl-sn-glycerol was less (P < 0.05) 1.5 h postprandially than at 2-5 h after palm oil, and less (P < 0.05) at 1.5 h than at 2-6 h after transesterified palm oil. This may be an indication of a loss of palmitic acid in the gut. Taken together, TAG molecular weight composition and to a lesser extent, positional distribution, seem to affect the rates of chylomicron TAG clearance in humans.
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Affiliation(s)
- Kaisa M Yli-Jokipii
- Department of Biochemistry and Food Chemistry, University of Turku, 20014 Turku, Finland.
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34
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35
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Kurvinen JP, Aaltonen J, Kuksis A, Kallio H. Software algorithm for automatic interpretation of mass spectra of glycerolipids. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2002; 16:1812-1820. [PMID: 12271445 DOI: 10.1002/rcm.785] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
A new software algorithm for automatic interpretation of mass spectra of glycerolipids has been developed. The algorithm utilizes a user-specified list of parameters needed to process the spectra. The compounds in mass spectra are identified according to range of measured m/z values, after which the spectra are automatically corrected by the content of naturally occurring isotopes and ion intensities of identified compounds by response correction factors. Automatic processing of the spectra was shown to be accurate and reliable by testing with numerous spectra of glycerophospholipids obtained by liquid chromatography/electrospray ionization mass spectrometry and by comparing the results with manual interpretation of the spectra. If quantitative analysis using internal standards is performed, all the identified compounds in the sample are quantified automatically. A dilution factor may be defined for each sample and is applied to correct the alterations in sample concentration during sample preparation. Processing of several replicate spectra simultaneously produces mean results with standard deviations. The software may also be used to subtract the results of two analyses and to calculate the mean result of replicate subtractions. The algorithm was shown to save time and labor in repetitive processing of mass spectra of similar type. It may be applied to processing of spectra obtained by various mass spectrometric methods.
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Affiliation(s)
- J-P Kurvinen
- Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku, Finland.
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36
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Molecular weight distribution and regioisomeric structure of triacylglycerols in some common human milk substitutes. J AM OIL CHEM SOC 2002. [DOI: 10.1007/s11746-002-0428-3] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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37
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Kurvinen JP, Mu H, Kallio H, Xu X, Høy CE. Regioisomers of octanoic acid-containing structured triacylglycerols analyzed by tandem mass spectrometry using ammonia negative ion chemical ionization. Lipids 2001; 36:1377-82. [PMID: 11834091 DOI: 10.1007/s11745-001-0855-9] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Tandem mass spectrometry based on ammonia negative ion chemical ionization and sample introduction via direct exposure probe was applied to analysis of regioisomeric structures of octanoic acid containing structured triacylglycerols (TAG) of type MML, MLM, MLL, and LML (M, medium-chain fatty acid; L, long-chain fatty acid). Collision-induced dissociation of deprotonated parent TAG with argon was used to produce daughter ion spectra with appropriate fragmentation patterns for structure determination. Fatty acids constituting the TAG molecule were identified according to [RCO2]- ions in the daughter ion spectra. With the standard curve for ratios of [M-H-RCO2H-100]- ions corresponding to each [RCO2]- ion, determined with known mixtures of sn-1/3 and sn-2 regioisomers of structured TAG, it was possible to determine the proportions of different regioisomers in unknown samples. The method enabled quantification of MML- and MLM-type structured TAG. In the case of MLL- and LML-type TAG, it was possible to determine the most abundant regioisomer in the unknown mixture and estimate the proportions of regioisomers when there were more than 50% MLL-type isomers in the mixture.
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Affiliation(s)
- J P Kurvinen
- Department of Biochemistry and Food Chemistry, University of Turku, Finland
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38
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Effects of palm oil and transesterified palm oil on chylomicron and VLDL triacylglycerol structures and postprandial lipid response. J Lipid Res 2001. [DOI: 10.1016/s0022-2275(20)32216-1] [Citation(s) in RCA: 48] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
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39
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Quantitation of acyl migration during lipase-catalyzed acidolysis, and of the regioisomers of structured triacylglycerols formed. J AM OIL CHEM SOC 2001. [DOI: 10.1007/s11746-001-0371-3] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/25/2022]
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40
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López-López A, Castellote-Bargalló AI, López-Sabater MC. Direct determination by high-performance liquid chromatography of sn-2 monopalmitin after enzymatic lipase hydrolysis. JOURNAL OF CHROMATOGRAPHY. B, BIOMEDICAL SCIENCES AND APPLICATIONS 2001; 760:97-105. [PMID: 11522071 DOI: 10.1016/s0378-4347(01)00257-2] [Citation(s) in RCA: 19] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
An alternative method to determine the sn-2 monopalmitin in infant formulas was developed and validated. This method offers many advantages over the traditional methods. It follows the official method in the first steps, purification of the fat or oil through an alumina column, and subsequently the triglycerides are incubated with pancreatic lipase in order to obtain the sn-2 monoglycerides. In traditional methods the sn-2 monoglycerides are separated by preparative thin-layer chromatography and then, the 2-monoglycerides are converted into the corresponding fatty acid methyl esters and analysed by gas chromatography. In our method, separation, quantification and identification of the sn-2 monoglycerides were achieved by high-performance liquid chromatography with evaporative light-scattering detection. The detection limit (0.19 microg), quantification limit (0.38 microg), linearity range (r=0.999, range 1-200 microg) and precision (SD=1.10) show the suitability of the proposed method. This method is faster, cheaper and simple and does not consume large quantities of reagents and materials.
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Affiliation(s)
- A López-López
- Dept. Nutrició i Bromatologia, Centre de Referència en Tecnologia dels Aliments, Facultat de Farmàcia, Universitat de Barcelona, Spain
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41
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Kallio H, Yli-Jokipii K, Kurvinen JP, Sjövall O, Tahvonen R. Regioisomerism of triacylglycerols in lard, tallow, yolk, chicken skin, palm oil, palm olein, palm stearin, and a transesterified blend of palm stearin and coconut oil analyzed by tandem mass spectrometry. JOURNAL OF AGRICULTURAL AND FOOD CHEMISTRY 2001; 49:3363-3369. [PMID: 11453776 DOI: 10.1021/jf010015w] [Citation(s) in RCA: 40] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Triacylglycerols (TAG) of lard, tallow, egg yolk, chicken skin, palm oil, palm olein, palm stearin, and a transesterified blend of palm stearin and coconut oil (82:18) were investigated by chemical ionization and collision-induced dissociation tandem mass spectrometry. Accurate molecular level information of the regioisomeric structures of individual TAGs was achieved. When existing in a TAG molecule of lard, palmitic acid occupied 90-100% of the sn-2 position. Within the major fatty acid combinations in tallow TAGs, the secondary position sn-2 was preferentially occupied in the decreasing order by oleoyl > palmitoyl > stearoyl residues, the order in saturated TAGs being myristoyl > stearoyl = palmitoyl. TAGs in egg yolk were more asymmetric than in chicken skin, with linoleic acid highly specifically attached in the yolk sn-2 carbon. Nearly 50% of yolk TAGs contained 52 carbon atoms with two or three double bonds. Linoleic, oleic, and palmitic acids were in the sn-2 location in decreasing quantities in palm oil and its fractions. Triacylglycerols of equal molecular weight behaved similarly in the fractionation process. Randomization of the parent oil TAGs was seen in the transesterified oil. The tandem mass spectrometric analysis applied provided detailed information of the distribution of fatty acids in individual combinations in TAGs.
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Affiliation(s)
- H Kallio
- Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku, Finland.
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42
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Kurvinen JP, Rua P, Sjövall O, Kallio H. Software (MSPECTRA) for automatic interpretation of triacylglycerol molecular mass distribution spectra and collision induced dissociation product ion spectra obtained by ammonia negative ion chemical ionization mass spectrometry. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2001; 15:1084-1091. [PMID: 11404845 DOI: 10.1002/rcm.340] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
Rapid analysis of molecular mass distributions of triacylglycerol (TAG) mixtures and regioisomeric structures of selected molecular mass species is possible using ammonia negative ion chemical ionization mass spectrometry utilizing sample introduction by direct exposure probe. However, interpretation of spectra and calculation of results is time consuming, thus lengthening the total analysis time. To facilitate result calculation a software package (MSPECTRA 1.3) was developed and applied to automatic processing of triacylglycerol molecular mass distribution spectra and collision induced dissociation (CID) product ion spectra. The program is capable of identifying triacylglycerol molecular mass species possessing different ACN:DB (acyl carbon number:number of double bonds) ratios on the basis of m/z values of [M - H](-) ions. In addition to such identification the program also corrects spectra for abundances of naturally occurring (13)C isotopes and calculates relative proportions of triacylglycerol molecular species in the analyzed samples. If several replicate spectra are processed simultaneously the program automatically calculates an average and standard deviation of relative proportions of molecular species. In the case of CID spectra the program identifies fatty acid fragment ions [RCO(2)](-) and the corresponding [M - H - RCO(2)H - 100](-) ions, and calculates the relative proportions of ions in both groups. These proportions are then used automatically to calculate the fatty acid combinations comprising the parent triacylglycerol molecule and the regiospecific positions of fatty acids. Processing of several replicate product ion spectra simultaneously produces averaged proportions of regioisomers comprising the parent triacylglycerol molecular species and the standard deviation of the analysis. The performance of the program was tested by analyzing triacylglycerol samples of human milk, human milk substitutes, human chylomicron and cocoa butter, and by comparing results obtained by automated processing of the data with manually calculated results.
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Affiliation(s)
- J P Kurvinen
- Department of Biochemistry and Food Chemistry, University of Turku, FIN-20014 Turku, Finland
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Jensen RG, Patton S. The effect of maternal diets on the mean melting points of human milk fatty acid. Lipids 2000; 35:1159-61. [PMID: 11104023 DOI: 10.1007/s11745-000-0632-9] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
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44
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Hsu FF, Turk J. Structural characterization of triacylglycerols as lithiated adducts by electrospray ionization mass spectrometry using low-energy collisionally activated dissociation on a triple stage quadrupole instrument. JOURNAL OF THE AMERICAN SOCIETY FOR MASS SPECTROMETRY 1999; 10:587-599. [PMID: 10384723 DOI: 10.1016/s1044-0305(99)00035-5] [Citation(s) in RCA: 141] [Impact Index Per Article: 5.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/23/2023]
Abstract
We describe features of tandem mass spectra of lithiated adducts of triacylglycerol (TAG) species obtained by electrospray ionization mass spectrometry (ms) with low-energy collisionally activated dissociation (CAD) on a triple stage quadrupole instrument. The spectra distinguish isomeric triacylglycerol species and permit assignment of the mass of each fatty acid substituent and positions on the glycerol backbone to which substituents are esterified. Source CAD-MS2 experiments permit assignment of double bond locations in polyunsaturated fatty acid substituents. The ESI/MS/MS spectra contain [M + Li - (RnCO2H)]+, [M + Li - (RnCO2Li)]+, and RnCO+ ions, among others, that permit assignment of the masses of fatty acid substituents. Relative abundances of these ions reflect positions on the glycerol backbone to which substituents are esterified. The tandem spectra also contain ions reflecting combined elimination of two adjacent fatty acid residues, one of which is eliminated as a free fatty acid and the other as an alpha, beta-unsaturated fatty acid. Such combined losses always involve the sn-2 substituent, and this feature provides a robust means to identify that substituent. Fragment ions reflecting combined losses of both sn-1 and sn-3 substituents without loss of the sn-2 substituent are not observed. Schemes are proposed to rationalize formation of major fragment ions in tandem mass spectra of lithiated TAG that are supported by studies with deuterium-labeled TAG and by source CAD-MS2 experiments. These schemes involve initial elimination of a free fatty acid in concert with a hydrogen atom abstracted from the alpha-methylene group of an adjacent fatty acid, followed by formation of a cyclic intermediate that decomposes to yield other characteristic fragment ions. Determination of double bond location in polyunsaturated fatty acid substituents of TAG is achieved by source CAD experiments in which dilithiated adducts of fatty acid substituents are produced in the ion source and subjected to CAD in the collision cell. Product ions are analyzed in the final quadrupole to yield information on double bond location.
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Affiliation(s)
- F F Hsu
- Department of Medicine, Washington University School of Medicine, St. Louis, Missouri 63110, USA
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45
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46
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Cheng C, Gross ML, Pittenauer E. Complete structural elucidation of triacylglycerols by tandem sector mass spectrometry. Anal Chem 1998; 70:4417-26. [PMID: 9796425 DOI: 10.1021/ac9805192] [Citation(s) in RCA: 159] [Impact Index Per Article: 6.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
We developed a method to elucidate the complete structure of triacylglycerols by means of high-energy collisional activation tandem mass spectrometry (MS/MS). Both ESI- and FAB-produced [M + NH4]+ and [M + met.]+ ions (where met. = Li, Na, and Cs) of triacylglycerols undergo charge-remote and charge-driven fragmentations. We emphasize the study of fragment ions from ESI-produced [M + NH4]+ and [M + Na]+ ions and FAB-produced [M + Na]+ ions. ESI-produced [M + NH4]+ ions fragment to produce four types of ions, [M + NH4 - RnCOONH4]+, [RnCO + 128]+, [RnCO + 74]+, and RnCO+ ions, from which the carbon number and the degree of unsaturation of each acyl group are obtained. In addition, three series of ions are produced by charge-remote fragmentations (CRFs), and analysis of their patterns gives the position and the number of double bonds on the acyl groups. Information about the position of each acyl group on the glycerol backbone, however, is not provided by collisionally activated dissociation of [M + NH4]+ ions. On the other hand, ESI- and FAB-produced [M + Na]+ ions fragment to form eight types of ions (named A-J ions) that, like those produced by CRF, are highly structurally informative. The absence of certain series members also carries useful structural information. Interpretation of these patterns enables one to obtain the number of carbons, degrees of unsaturation, and location of double bonds, as well as the positions of acyl groups on the glycerol backbone.
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Affiliation(s)
- C Cheng
- Department of Chemistry, Washington University, St. Louis, Missouri 63130, USA
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47
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Morera Pons S, Castellote Bargalló AI, López Sabater MC. Analysis of human milk triacylglycerols by high-performance liquid chromatography with light-scattering detection. J Chromatogr A 1998; 823:475-82. [PMID: 9818421 DOI: 10.1016/s0021-9673(98)00584-6] [Citation(s) in RCA: 38] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/09/2023]
Abstract
A high-performance liquid chromatography (HPLC) method for the separation of human milk triacylglycerols using a C18 Spherisorb ODS column and ternary gradient elution with dichloromethane, acetone and acetonitrile is described. The triacylglycerols are detected by light scattering. Several chromatographic conditions were assayed in order to optimize the method: sample solubility, mobile phase, column temperature and the mass detector oven temperature. The linearity, precision and relative response of the method were examined. A total of 34 peaks were separated and quantified based on the percentage peak area in the HPLC chromatogram. Mature human milk analyzed by this method contained six predominant triacylglyceride structures: POO, POL, LOO, POP, OOO and SOP, where P = palmitin, O = olein, L = linolein and S = stearin.
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Affiliation(s)
- S Morera Pons
- Unitat de Nutrició i Bromatologia-CERTA, Facultat de Farmàcia, Universitat de Barcelona, Spain
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48
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Laakso P. Analysis of triacylglycerols— approaching the molecular composition of natural mixtures. FOOD REVIEWS INTERNATIONAL 1996. [DOI: 10.1080/87559129609541075] [Citation(s) in RCA: 26] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
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49
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Abstract
The summary will be limited to the areas that should be intensively investigated. The first is: determination of fatty acid profiles using modern methods on a world wide basis. We have no more than five or six papers in which my criterion was applied, one from Canada and the remainder from Europe with some data from Africa. Obviously, milk cannot be used as the gold standard on this meager data base. The second area is analysis of TG structure. These analyses are difficult, but structure is one of the factors controlling digestion. Data on the effects of maternal diet on structure would be useful. The third area is the role of primary or derived milk lipids as microbicidal agents. The fourth area is examination of globule parameters, i.e. number, size, volume, surface, and how they are affected by diet. There are many others which may interest the reader.
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Affiliation(s)
- R G Jensen
- Department of Nutritional Sciences, University of Connecticut, Storrs 06269-4017, USA
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Kalo P, Kemppinen A, Kilpeläinen I. Determination of positional distribution of butyryl groups in milkfat triacylglycerols, triacylglycerol mixtures, and isolated positional isomers of triacylglycerols by gas chromatography and 1H nuclear magnetic resonance spectroscopy. Lipids 1996; 31:331-6. [PMID: 8900463 DOI: 10.1007/bf02529880] [Citation(s) in RCA: 22] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/02/2023]
Abstract
Positional isomers (1-butyryl-2X-3Y-rac-glycerol and 2-butyryl-1X-3Y-rac-glycerol; X,Y = long-chain acyls) of saturated triacylglycerols (TAG) within 34 and 40 acyl carbons were shown to separate in two chromatographic peaks on immobilized phenyl(65%)methylsilicone column by gas-liquid chromatography, and on reversed-phase ODS-1 column by high-performance liquid chromatography. The analysis of 500-MHz 1H nuclear magnetic resonance (NMR) spectra showed distinct differences between 2-butyryl-1X-3Y-rac-glycerol and 1-butyryl-2X-3Y-rac-glycerol isomers in the resonance signals of methylene and methine protons of glycerol backbone, and carbon-2 methylene of acyl groups, and methyl protons of butyryl group. The 1H NMR spectra of three interesterified mixtures of three monacid TAG containing saturated butyrate and caproate TAG and unsaturated butyrate TAG showed that triplets of methyl protons of butyryl groups at sn-1(3)- and sn-2-positions in saturated and unsaturated TAG had similar chemical shifts and that the chemical shift of caproyl methyl protons was different from those of butyryl methyl protons. The positional distribution of butyryl groups in isolated positional isomers of butyrate TAG, interesterified TAG mixtures, and natural and interesterified butteroil can be determined by integration of these signals.
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Affiliation(s)
- P Kalo
- Department of Applied Chemistry and Microbiology, University of Helsinki, Finland
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