Publications by authors named "Marika Kalpio"

12 Publications

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A novel UHPLC-ESI-MS/MS method and automatic calculation software for regiospecific analysis of triacylglycerols in natural fats and oils.

Anal Chim Acta 2022 Jun 1;1210:339887. Epub 2022 May 1.

Food Chemistry and Food Development, Department of Life Technologies, FI-20500, University of Turku, Turku, Finland. Electronic address:

Regioisomeric analysis of triacylglycerols (TAGs) in natural oils and fats is a highly challenging task in analytical chemistry. Here we present a software (TAG Analyzer) for automatic calculation of regioisomeric composition of TAGs based on the mass spectral data from recently reported ultra-high performance liquid chromatography electrospray ionization tandem mass spectrometry (UHPLC-ESI-MS/MS) method for analyzing TAG regioisomers. The software enables fast and accurate processing of complex product ion spectra containing structurally informative diacylglycerol [M+NH-RCOH-NH] and fatty acid ketene [RCO] fragment ions. Compared to manual processing, the developed software offers higher throughput with faster calculation as well as more accurate interpretation of chromatographically overlapping isobaric TAGs. The software determines results by constructing a synthetic spectrum to match the measured fragment ion spectrum, and by reporting the optimal concentrations of TAGs used to create the synthetic spectrum. This type of calculation is often extremely challenging for manual interpretation of the fragment ion spectra of isobaric TAGs with shared fragments, hence the need for automated data processing. The developed software was validated by analyzing a wide range of mixtures of regiopure TAG reference compounds of known composition and a commercial olive oil sample. Additionally, the method was also applied for regiospecific analysis of TAGs in human milk as an example of natural fats and oils with a highly complex TAG profile. The results indicate that the software is capable of resolving regioisomeric composition of natural TAGs even of the most complex composition. This novel calculation software combined with our existing UHPLC-ESI-MS/MS method form a highly efficient tool for regioisomeric analysis of TAGs in natural fats and oils.
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http://dx.doi.org/10.1016/j.aca.2022.339887DOI Listing
June 2022

Strategy for stereospecific characterization of natural triacylglycerols using multidimensional chromatography and mass spectrometry.

J Chromatogr A 2021 Mar 12;1641:461992. Epub 2021 Feb 12.

Food Chemistry and Food Development, Department of Life Technologies, University of Turku, FI-20014 Turku, Finland.

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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http://dx.doi.org/10.1016/j.chroma.2021.461992DOI Listing
March 2021

Synthesis and enantiospecific analysis of enantiostructured triacylglycerols containing n-3 polyunsaturated fatty acids.

Chem Phys Lipids 2020 09 27;231:104937. Epub 2020 Jun 27.

Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland. Electronic address:

The stereospecific structure of triacylglycerols (TAGs) affects the bioavailability of fatty acids. Lack of enantiopure reference compounds and effective enantiospecific methods have hindered the stereospecific analysis of individual TAGs. Twelve novel enantiostructured AAB-type TAGs were synthesized containing one of the three n-3 polyunsaturated fatty acid: α-linolenic acid (ALA), eicosapentaenoic acid (EPA), or docosahexaenoic acid (DHA) in sn-1 or sn-3 position. These compounds formed six enantiomer pairs, which were separated with recycling high-performance liquid chromatography using chiral columns and UV detection. The chromatographic retention behavior of the enantiomers and the stereospecific elution order were studied. The enantiomer with an n-3 PUFA in the sn-1 position eluted faster than the enantiomer with the n-3 PUFA in the sn-3 position, regardless of the carbon chain length and number of double bonds of the PUFA. TAG enantiomers containing DHA exhibited highly different retention on the chiral column and were separated after the first column, whereas recycling was needed to separate the enantiomer pairs containing ALA or EPA. The system using two identical columns and one mobile phase, without sample derivatization, proved to be very effective also for peak purity assessment, confirming the enantiopurity of the synthesized structured TAGs being higher than 98 % (96 % ee).
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http://dx.doi.org/10.1016/j.chemphyslip.2020.104937DOI Listing
September 2020

Direct inlet negative ion chemical ionization tandem mass spectrometric analysis of triacylglycerol regioisomers in human milk and infant formulas.

Food Chem 2020 Oct 6;328:126991. Epub 2020 May 6.

Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland. Electronic address:

A previously developed direct inlet tandem mass spectrometric method for analysis of triacylglycerol (TAG) regioisomers was updated and validated for operation with current instrumentation with improved sensitivity and throughput. TAG regioisomers in pooled Chinese and Finnish human milk samples, two bovine milk samples and 11 infant formulas were identified and quantified. A total of 241 TAG regioisomers were identified and quantified, consisting of over 60 mol% of all TAGs in the human milk samples. The infant formulas deviated largely from human milk in regioisomeric composition of TAGs. In the Finnish and Chinese human milks, the most abundant ones were 1,3-dioleoyl-2-palmitoylglycerol (OPO; 7.4 and 8.8 mol% of all TAGs) and 1(3)-linoleoyl-2-palmitoyl-3(1)-oleoylglycerol (LPO; 4.7 and 8.3 mol% of all TAGs). In the infant formulas 1,2(2,3)-dioleoyl-3(1)-palmitoylglycerol (OOP) and 1(3)-linoleoyl-2-oleoyl-3(1)-palmitoylglycerol/1(3)-palmitoyl-2-linoleoyl-3(1)-oleoylglycerol (LOP/PLO) were more abundant than OPO and LPO. The differences between human milk and infant formula prompt for further development of current formulas.
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http://dx.doi.org/10.1016/j.foodchem.2020.126991DOI Listing
October 2020

Chemical composition of bilberry wine fermented with non-Saccharomyces yeasts (Torulaspora delbrueckii and Schizosaccharomyces pombe) and Saccharomyces cerevisiae in pure, sequential and mixed fermentations.

Food Chem 2018 Nov 4;266:262-274. Epub 2018 Jun 4.

Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland. Electronic address:

This study evaluated the effects of fermentation with pure cultures of Torulaspora delbrueckii (TD291 and TD70526) and Schizosaccharomyces pombe (SP3796 and SP70572), as well as in sequential and mixed inoculations with Saccharomyces cerevisiae, on the chemical composition of bilberry wine. In comparison to the bilberry wines produced by pure and sequential fermentations, mixed cultures produced bilberry wines with more ethanol, higher pH values, higher percentages of red and yellow shade, but less glycerol and acetaldehyde. Higher values of color intensity and bluish parameter were found in products of pure fermentations with non-Saccharomyces yeasts. Compared to S. cerevisiae, T. delbrueckii contributed to the reduction of ethanol and acetic acid while increasing the content of succinic acid, lactic acid and higher alcohols; S. pombe consumed malic acid almost completely and produced more glycerol, acetaldehyde and/or pyruvic acid. Fermentation with SP70572 had the highest amounts of anthocyanins and hydroxycinnamic acids derivatives.
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http://dx.doi.org/10.1016/j.foodchem.2018.06.003DOI Listing
November 2018

Effects of Insect Herbivory on Bilberry Production and Removal of Berries by Frugivores.

J Chem Ecol 2017 Apr 3;43(4):422-432. Epub 2017 Apr 3.

Section of Ecology, Department of Biology, University of Turku, 20014, Turku, FI, Finland.

The evolutionary purpose of a fleshy fruit is to attract seed dispersers and get the seeds dispersed by frugivorous animals. For this reason, fruits should be highly rewarding to these mutualists. However, insect herbivory can alter plant reproductive success e.g. by decreasing fruit yield or affecting the attractiveness of the fruits to mutualistic seed dispersers. Under natural conditions, we tested the effects of experimental larval-defoliation on berry ripening and consumption of a non-cultivated dwarf shrub, the bilberry (Vaccinium myrtillus L.), which produces animal-dispersed berries with high sugar and anthocyanin concentration. Bilberry ramets with high fruit yield were most likely to have their berries foraged, indicating that frugivores made foraging choices based on the abundance of berries. Moreover, the probability for berries being foraged was the lowest for non-defoliated ramets that grew adjacent to larval-defoliated ramets, even though larval-defoliation did not affect the biochemical composition (total concentrations of anthocyanins, sugars and organic acids) or the probability of ripening of berries. We hypothesise that the lower probability for berries being foraged in these ramets may be a consequence of rhizome- or volatile-mediated communication between ramets, resulting in a priming effect of the herbivore defence and lower attractiveness of the non-defoliated ramets.
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http://dx.doi.org/10.1007/s10886-017-0838-8DOI Listing
April 2017

In situ quantitative H nuclear magnetic resonance spectroscopy discriminates between raw and steam cooked potato strips based on their metabolites.

Talanta 2016 Dec 19;161:245-252. Epub 2016 Aug 19.

Functional Foods Forum, University of Turku, FI 20014 Turku, Finland. Electronic address:

A direct quantitative proton nuclear magnetic resonance spectroscopy method was developed for the measurement of saccharides, organic acids and amino acids in potato (Solanum tuberosum L.) tuber filaments, a complex gel-like food matrix. The method requires minimal sample preparation. It is thus a faster alternative compared to liquid sample matrices, as well as an extension to methods analyzing only selected metabolites in the sample. The samples in this study were either raw or steamed potato strips that were either measured as DO extracts or directly without extraction or derivatization steps (in situ technique). A total of 22 compounds were identified in extracts and 18 in potato strips. Of these, 20 compounds were quantifiable in potato extracts and 13 compounds in potato strips. The effect of thermal processing was reflected in the profile of analyzed compounds. One example was fumaric acid, which was completely lost in steamed samples in both measurement techniques. Additionally, the content of γ-aminobutyric acid in steamed potato strips was lower. In potato extracts, the contents of additional 7 compounds were statistically different. The raw and steamed samples separated into two groups with multivariate models both in extracts and potato strips, and these groups were linked to changes in aforementioned compounds. These results demonstrated that the in situ quantitative H NMR technique is a useful tool to analyze potato metabolites. This technique could be further applied to any gel-like complex matrix, meaning that lengthy sample pretreatment could be skipped.
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http://dx.doi.org/10.1016/j.talanta.2016.08.056DOI Listing
December 2016

Comparison of the postprandial effects of purple-fleshed and yellow-fleshed potatoes in healthy males with chemical characterization of the potato meals.

Int J Food Sci Nutr 2015 Aug 10;67(5):581-91. Epub 2016 May 10.

a Division of Food Chemistry and Food Development, Department of Biochemistry , University of Turku , Turku , Finland ;

The aim of the current study was to characterize the anthocyanin content and composition of a purple potato landrace cultivar (Solanum tuberosum 'Synkeä Sakari') and to compare the postprandial effects of purple-fleshed potatoes, yellow-fleshed potatoes and bilberries in potato starch on postprandial glycemia and insulinemia in healthy males. The purple potato meal caused smaller insulinemia than the yellow potato meal (iAUC 120 min 1347 and 2226, respectively, p = 0.012 and iAUC 240 min 1448 and 2403, p = 0.007) or the bilberry meal (iAUC 120 min 1920, p = 0.027). The purple potato meal caused a smaller plasma glucose at 40 min postprandially compared with the yellow potato meal (p = 0.044). The results of this study suggest that anthocyanin-containing purple-fleshed potatoes influence the postprandial insulinemia positively. Since potatoes are the world's largest non-grain commodity, replacing yellow-fleshed potatoes with purple-fleshed potatoes as staple food could have large potential in maintaining public health.
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http://dx.doi.org/10.1080/09637486.2016.1181157DOI Listing
August 2015

Triacylglycerol biosynthesis in developing Ribes nigrum and Ribes rubrum seeds from gene expression to oil composition.

Food Chem 2016 Apr 9;196:976-87. Epub 2015 Oct 9.

Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland; The Kevo Subarctic Research Institute, University of Turku, Turku FI-20014, Finland.

Oils with sufficient contents of fatty acids, which can be metabolized into precursors of anti-inflammatory eicosanoids, have potential health effects. Ribes sp. seed oil is rich in α-linolenic, γ-linolenic and stearidonic acids belonging to this fatty acid group. Only a few previous studies exist on Ribes sp. gene expression. We followed the seed oil biosynthesis of four Ribes nigrum and two Ribes rubrum cultivars at different developmental stages over 2 years in Southern and Northern Finland with a 686 km latitudinal difference. The species and the developmental stage were the most important factors causing differences in gene expression levels and oil composition. Differences between cultivars were detected in some cases, but year and location had only small effects. However, expression of the gene encoding Δ(9)-desaturase in R. nigrum was affected by location. Triacylglycerol biosynthesis in Ribes sp. was distinctly buffered and typically followed a certain path, regardless of growth environment.
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http://dx.doi.org/10.1016/j.foodchem.2015.10.010DOI Listing
April 2016

Enantioselective chromatography in analysis of triacylglycerols common in edible fats and oils.

Food Chem 2015 Apr 30;172:718-24. Epub 2014 Sep 30.

Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland. Electronic address:

Enantiomers of racemic triacylglycerol (TAG) mixtures were separated using two chiral HPLC columns with a sample recycling system and a UV detector. A closed system without sample derivatisation enabled separation and identification by using enantiopure reference compounds of eleven racemic TAGs with C12-C22 fatty acids with 0-2 double bonds. The prolonged separation time was compensated for by fewer pretreatment steps. Presence of one saturated and one unsaturated fatty acid in the asymmetric TAG favoured the separation. Enantiomeric resolution, at the same time with stronger retention of TAGs, increased with increasing fatty acid chain length in the sn-1(3) position. Triunsaturated TAGs containing oleic, linoleic or palmitoleic acids did not separate. The elution order of enantiomers was determined by chemoenzymatically synthesised enantiopure TAGs with a co-injection method. The method is applicable to many natural fats and oils of low unsaturation level assisting advanced investigation of lipid synthesis and metabolism.
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http://dx.doi.org/10.1016/j.foodchem.2014.09.135DOI Listing
April 2015

Tandem mass spectrometric analysis of human milk triacylglycerols from normal weight and overweight mothers on different diets.

Food Chem 2014 Mar 25;146:583-90. Epub 2013 Sep 25.

Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland. Electronic address:

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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http://dx.doi.org/10.1016/j.foodchem.2013.09.092DOI Listing
March 2014

Coordinate changes in gene expression and triacylglycerol composition in the developing seeds of oilseed rape (Brassica napus) and turnip rape (Brassica rapa).

Food Chem 2014 Feb 5;145:664-73. Epub 2013 Sep 5.

Department of Biochemistry, University of Turku, FI-20014 Turku, Finland.

Crop production for vegetable oil in the northern latitudes utilises oilseed rape (Brassica napus subsp. oleifera) and turnip rape (B. rapa subsp. oleifera), having similar oil compositions. The oil consists mostly of triacylglycerols, which are synthesised during seed development. In this study, we characterised the oil composition and the expression levels of genes involved in triacylglycerol biosynthesis in the developing seeds in optimal, low temperature (15 °C) and short day (12-h day length) conditions. Gene expression levels of several genes were altered during seed development. Low temperature and short day treatments increased the level of 9,12,15-octadecatrienoic acid (18:3n-3) in turnip rape and short day treatment decreased the total oil content in both species. This study gives a novel view on seed oil biosynthesis under different growth conditions, bringing together gene expression levels of the triacylglycerol biosynthesis pathway and oil composition over a time series in two related oilseed species.
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http://dx.doi.org/10.1016/j.foodchem.2013.08.108DOI Listing
February 2014
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