Publications by authors named "Heikki Kallio"

108 Publications

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

Health promoting properties and sensory characteristics of phytochemicals in berries and leaves of sea buckthorn ().

Crit Rev Food Sci Nutr 2022 7;62(14):3798-3816. Epub 2021 Jan 7.

Food Chemistry and Food Development, Department of Biochemistry, University of Turku, Turku, Finland.

Sea buckthorn ( L., SB), as a multi-functional plant, is widely grown in Asia, Europe and Canada. The berries and leaves of SB contain a diverse array of health-supporting phytochemicals, which are also related to the sensory qualities of berry and berry products. This review summarizes the biologically active key-compounds of the berries and leaves of SB, their health-promoting effects, as well as the contributions to the sensory quality of the berries. The target compounds consist of sugars, sugar derivatives, organic acids, phenolic compounds and lipophilic compounds (mainly carotenoids and tocopherols), which play an important role in anti-inflammatory and antioxidant functions, as well as in metabolic health. In addition, these compounds contribute to the orosensory qualities of SB berries, which are closely related to consumer acceptance and preference of the products. Studies regarding the bioavailability of the compounds and the influence of the processing conditions are also part of this review. Finally, the role of the sensory properties is emphasized in the development of SB products to increase utilization of the berry as a common meal component and to obtain value-added products to support human health.
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http://dx.doi.org/10.1080/10408398.2020.1869921DOI Listing
May 2022

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

Impact of cultivar, growth temperature and developmental stage on phenolic compounds and ascorbic acid in purple and yellow potato tubers.

Food Chem 2020 Oct 4;326:126966. Epub 2020 May 4.

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

Phenolic compounds and ascorbic acid were analyzed in one yellow and four purple-flesh potato cultivars grown at 13 °C and 18 °C and harvested at different stages of tuber development, using HPLC-DAD and UHPLC-MS. The expression of genes in the phenylpropanoid pathway was studied at transcription level using qPCR. Petunidin-3-p-coumaroylrutinoside-5-glucoside was the most abundant anthocyanin in 'Blue Congo', 'Blaue Schweden', and 'Synkeä Sakari', whereas malvidin-3-p-coumaroylrutinoside-5-glucoside dominated in 'Blaue Veltlin'. In mature tubers, the purple cultivar 'Synkeä Sakari' showed the highest content of anthocyanins (2.4 mg/g freeze-dried sample), and 'Blaue Veltlin' had the highest content of phenolic acids (5.5 mg/g). Cultivar was the main variable affecting the biosynthesis of the studied metabolites, whereas the temperatures studied did not show different impact. The content of the main phenolic acids and anthocyanins in the potato cultivars correlated positively with the expression levels of the genes involved in the phenylpropanoid pathway.
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http://dx.doi.org/10.1016/j.foodchem.2020.126966DOI Listing
October 2020

Anthocyanin-rich extract from purple potatoes decreases postprandial glycemic response and affects inflammation markers in healthy men.

Food Chem 2020 Apr 26;310:125797. Epub 2019 Oct 26.

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

Our recent clinical study suggested that polyphenol-rich purple potatoes lowered postprandial glycemia and insulinemia compared to yellow potatoes. Here, 17 healthy male volunteers consumed yellow potatoes with or without purple potato extract (PPE, extracted with water/ethanol/acetic acid) rich in acylated anthocyanins (152 mg) and other phenolics (140 mg) in a randomized cross-over trial. Ethanol-free PPE decreased the incremental area under the curve for glucose (p = 0.019) and insulin (p = 0.015) until 120 min after the meal, glucose at 20 min (p = 0.015) and 40 min (p = 0.004), and insulin at 20 min (p = 0.003), 40 min (p = 0.004) and 60 min (p = 0.005) after the meal. PPE affected some of the studied 90 inflammation markers after meal; for example insulin-like hormone FGF-19 levels were elevated at 240 min (p = 0.001). These results indicate that PPE alleviates postprandial glycemia and insulinemia, and affects postprandial inflammation.
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http://dx.doi.org/10.1016/j.foodchem.2019.125797DOI Listing
April 2020

Effects of Latitude and Weather Conditions on Proanthocyanidins in Blackcurrant () of Finnish Commercial Cultivars.

J Agric Food Chem 2019 Dec 11;67(51):14038-14047. Epub 2019 Dec 11.

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

Blackcurrants of three Finnish commercial cultivars 'Mortti', 'Ola', and 'Melalahti' cultivated in southern and northern Finland were compared on the basis of the content and composition of proanthocyanidins (PAs). Seventeen B-type PA oligomers (degree of polymerization 2-5 and 7) were detected by hydrophilic interaction liquid chromatography and electrospray ionization mass spectrometry. Total PAs, dimers, trimers, and tetramers were quantified. Among the three cultivars, 'Ola' had the highest contents of both total PAs and PA oligomers. 'Melalahti' was separated from both 'Mortti' and 'Ola' by PA profiles in the partial least-squares discriminant analysis model. All three cultivars revealed distinct responses to latitude and weather conditions. The content of total PAs showed a positive correlation to latitude in 'Ola' and 'Melalahti'. Among the meteorological variables, high temperature and radiation correlated negatively with total PAs, while only specific variables showed a correlation with PA oligomers.
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http://dx.doi.org/10.1021/acs.jafc.9b06031DOI Listing
December 2019

Regiospecific Analysis of Triacylglycerols by Ultrahigh-Performance-Liquid Chromatography-Electrospray Ionization-Tandem Mass Spectrometry.

Anal Chem 2019 11 23;91(21):13695-13702. Epub 2019 Oct 23.

Food Chemistry and Food Development, Department of Biochemistry, Faculty of Science and Engineering , University of Turku Turun yliopisto FI-20014 Finland.

An ultrahigh-performance-liquid chromatography-electrospray ionization-tandem mass spectrometry (UHPLC-ESI-MS/MS) method was developed for the analysis of AAB and ABC type triacylglycerol (TG) regioisomers. Excellent linear regressions were established between the ratio of [RR] product ions and the proportion of regioisomers of TGs. The method was further optimized by analysis of 18 regiospecific pairs of AAB type TGs and five triplets of regioisomers of ABC type TGs with acyl carbon number (ACN) ranging from 36 to 54 and the number of double bonds (DB) from 0 to 7. Reverse linear relationships were recognized between the slope of the calibration curve and the number of double bonds of the -2 fatty acids. Negative linear regressions were found between the intercepts of the calibration curves and the sum of ACN + DB of -2 fatty acids. The method was highly repeatable as shown by the low deviation and high stability of the calibration curves at different concentrations and between different periods of analysis. This is the first time that calibration curves for the ABC type TGs are reported. The results provide crucial and novel information for reliable and quantitative determination of regioisomeric TGs in natural fats and oils.
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http://dx.doi.org/10.1021/acs.analchem.9b02968DOI Listing
November 2019

Regulation of phytochemicals in fruits and berries by environmental variation-Sugars and organic acids.

J Food Biochem 2019 06 28;43(6):e12642. Epub 2018 Aug 28.

Department of Food Science and Engineering, Jinan University, Guangzhou, China.

Sugars and organic acids are important phytochemicals contributing to the nutrition and sensory properties of fruits and berries. Their contents are closely correlated to the genetic background of plants as well as to the environmental conditions during growth. This review focuses on the recent researches on the metabolism of these compounds in fruits and berries in response to the variation of environmental conditions, including temperature, radiation, and water supply. A great deal of investigations indicates that the influence of environmental factors on the composition of fruits/berries depended largely on the genetic background. Moreover, the metabolic regulation in response to environmental changes also varies between different plant developmental stages. Nevertheless, some general trends, like the positive correlation between light intensity and sugar content, were observed in most investigations. In grapes (Vitis vinifera L.), the content of malic acid always decreases as light intensity increases, and as the water supply decreases. PRACTICAL APPLICATIONS: The contents of sugars and organic acids, and especially their relative ratio, are important indicators determining the taste and quality of fruits and fruit products. In this review, we summarized the investigations carried out on the regulation of these sensory contributing primary metabolites in fruits and berries in relation to the variation of environmental conditions. It was indicated that various factors, such as plant genotype, growing period, and interaction between environmental factors, might contribute to the impact of environmental changes on the composition of fruits/berries. The article not only provides comprehensive knowledges in food chemistry and plant physiology but also provide important background knowledge for berry cultivation and breeding, as well as useful guidelines for utilization of fruits and berries in food industry.
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http://dx.doi.org/10.1111/jfbc.12642DOI Listing
June 2019

Bioavailability of docosahexaenoic acid 22:6(n-3) from enantiopure triacylglycerols and their regioisomeric counterpart in rats.

Food Chem 2019 Jun 14;283:381-389. Epub 2019 Jan 14.

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

Lack of synthetic enantiospecific triacylglycerols (TAGs) has hindered our understanding of the impact of TAG structure on the absorption and metabolic fate of fatty acids (FAs). In a five-day feeding trial with mildly (n-3) deficient rats, the bioavailability of docosahexaenoic acid [22:6(n-3), DHA] and stearic acid (18:0) from the two different enantiomers of TAG: sn-22:6(n-3)-18:0-18:0 and sn-18:0-18:0-22:6(n-3), and their regioisomeric TAG: sn-18:0-22:6(n-3)-18:0 was compared. Less secretion of fecal DHA was detected from the sn-2 position compared with the sn-1 and sn-3 positions, but no difference was found in DHA content of the fasting plasma or in the weight of the body or organs. 18:0 was lost to feces mainly as cleaved from the primary positions but also as glycerol-bound. The 5-day intervention in rats was long enough to modify the fatty acid profile of plasma phospholipids.
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http://dx.doi.org/10.1016/j.foodchem.2018.12.130DOI Listing
June 2019

Effects of a sea buckthorn oil spray emulsion on dry eye.

Cont Lens Anterior Eye 2019 08 26;42(4):428-433. Epub 2018 Nov 26.

Turun Silmäexpertit Ltd, Turku, Finland.

Purpose: To investigate the effects of a sea buckthorn oil and sodium hyaluronate-containing eyelid spray emulsion (SB spray) on dry eye.

Methods: A randomized controlled study was carried out. Adults (25-70 years) with Ocular Surface Disease Index (OSDI) ≥20 and moderate or severe dryness, burning or grittiness of the eyes were included. In study part one (n = 2), SB spray was used on both closed eyelids four times in one day. In part two (n = 10), SB spray was used on one randomized eyelid, and a commercial reference spray on the other for nine days. In part three (n = 40), eyes were randomized to one eye receiving SB spray and an untreated control for 1.5 months. Dry eye tests were carried out at baseline, during, and at the end of each study section. Symptoms were recorded in questionnaires and daily logs.

Results: In part one, the SB spray was well tolerated. In part two, OSDI decreased significantly (P = 0.022) in the SB spray eye compared to the reference spray, indicating a beneficial effect on symptoms. In part three, OSDI in the SB spray eye decreased significantly compared to the untreated control (P = 0.0007). The scores for dryness at the study end were lower in the SB spray eye compared to control (P = 0.0070). Symptom sums and frequencies of dryness (sum P = 0.0046, frequency P = 0.0016) and watering (sum P = 0.0003, frequency P = 0.013) in the daily logs were lower in the eye treated with SB spray.

Conclusions: SB spray on closed eyelids relieved the symptoms of dry eye.
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http://dx.doi.org/10.1016/j.clae.2018.11.011DOI Listing
August 2019

Profiles of Volatile Compounds in Blackcurrant ( Ribes nigrum) Cultivars with a Special Focus on the Influence of Growth Latitude and Weather Conditions.

J Agric Food Chem 2018 Jul 9;66(28):7485-7495. Epub 2018 Jul 9.

Food Chemistry and Food Development, Department of Biochemistry , University of Turku , FI-20014 Turun yliopisto , Finland.

The volatile profiles of three blackcurrant ( Ribes nigrum L.) cultivars grown in Finland and their responses to growth latitude and weather conditions were studied over an 8 year period by headspace solid-phase microextraction (HS-SPME) followed by gas-chromatographic-mass-spectrometric (GC-MS) analysis. Monoterpene hydrocarbons and oxygenated monoterpenes were the major classes of volatiles. The cultivar 'Melalahti' presented lower contents of volatiles compared with 'Ola' and 'Mortti', which showed very similar compositions. Higher contents of volatiles were found in berries cultivated at the higher latitude (66° 34' N) than in those from the southern location (60° 23' N). Among the meteorological variables, radiation and temperature during the last month before harvest were negatively linked with the volatile content. Storage time had a negative impact on the amount of blackcurrant volatiles.
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http://dx.doi.org/10.1021/acs.jafc.8b02070DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6221373PMC
July 2018

Red/Green Currant and Sea Buckthorn Berry Press Residues as Potential Sources of Antioxidants for Food Use.

J Agric Food Chem 2018 Apr 23;66(13):3426-3434. Epub 2018 Mar 23.

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

The potential for using extracts of press residues from black, green, red, and white currants and from sea buckthorn berries as sources of antioxidants for foods use was investigated. Press residues were extracted with ethanol in four consecutive extractions, and total Folin-Ciocalteu (F-C) reactive material and authentic phenolic compounds were determined. Radical quenching capability and mechanisms were determined from total peroxyl radical-trapping antioxidant capacity (TRAP) and oxygen radical absorbance capacity (ORAC) assays and from diphenylpicrylhydrazyl (DPPH) kinetics, respectively; specific activities were normalized to F-C reactive concentrations. Levels of total F-C reactive materials in press residue extracts were higher than in many fruits and showed significant radical quenching activity. Black currant had the highest authentic phenol content and ORAC, TRAP, and DPPH reactivity. Sea buckthorn grown in northern Finland showed extremely high total specific DPPH reactivity. These results suggest that berry press residues offer attractive value-added products that can provide antioxidants for use in stabilizing and fortifying foods.
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http://dx.doi.org/10.1021/acs.jafc.8b00177DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6203183PMC
April 2018

Historical Review on the Identification of Mesifurane, 2,5-Dimethyl-4-methoxy-3(2 H)-furanone, and Its Occurrence in Berries and Fruits.

Authors:
Heikki P Kallio

J Agric Food Chem 2018 Mar 5;66(11):2553-2560. Epub 2018 Mar 5.

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

Mesifurane, 2,5-dimethyl-4-methoxy-3(2 H)-furanone, is a natural compound used a worldwide as a flavoring for foods, beverages, and cosmetics. Global sales of mesifurane are around $100 million. Its significance as a flavor-impact compound in some Nordic berries was discovered in the early 1970s in Finland. Synthesized mesifurane was used as a key compound in aroma mixes exploited in a Finnish patent. Mesifurane is a significant flavorant in arctic brambles, mangoes, strawberries, and many other fruits and berries and is an enzymatic methylation product of 2,5-dimethyl-4-hydroxy-3(2 H)-furanone. Because of the obscurity of the information on the history of the commonly used trivial name, mesifurane, it is time to lift the veil and reveal the background of the present situation. The key player was a northern berry, arctic bramble ( Rubus arcticus), the Finnish name of which is mesimarja. Forty years ago, aroma research was limited by technical factors, but nowadays there is a surplus of information.
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http://dx.doi.org/10.1021/acs.jafc.8b00519DOI Listing
http://www.ncbi.nlm.nih.gov/pmc/articles/PMC6203179PMC
March 2018

Improved analysis of anthocyanins and vitamin C in blue-purple potato cultivars.

Food Chem 2018 Mar 9;242:217-224. Epub 2017 Sep 9.

Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland; Department of Food Science and Engineering, Jinan University, 510632 Guangzhou, China. Electronic address:

Methods were optimized for extraction and quantification of anthocyanins (ACY) and vitamin C in potatoes. Acidified aqueous methanol (70%) was the optimal extraction solvent and freeze-drying significantly improved the extraction yield of ACY. The content of ACY varied widely in five potato cultivars from 0.42 to 3.18mg/g dry weight, with the latter being the highest value found in the Finnish cultivar 'Synkeä Sakari'. Compared with dithiothreitol (DTT), tris(2-carboxyethyl) phosphine hydrochloride (TCEP) was more efficient in reducing dehydroascorbic acid (DHA) to ascorbic acid (AA) and for quantifying the content of total ascorbic acid (TAA). For raw potatoes, quantification of TAA after treatment with TCEP was more reliable than a direct analysis of AA, whereas AA can be analyzed directly in steam-cooked samples. The TAA contents in the three potato cultivars were around 0.30-0.35mg/g dry weight. The loss of AA in steam cooking was 24%.
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http://dx.doi.org/10.1016/j.foodchem.2017.09.002DOI Listing
March 2018

Role of Flavonols and Proanthocyanidins in the Sensory Quality of Sea Buckthorn (Hippophaë rhamnoides L.) Berries.

J Agric Food Chem 2017 Nov 1;65(45):9871-9879. Epub 2017 Nov 1.

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

Sensory profile, flavonols, proanthocyanidins, sugars, and organic acids were investigated in purees of six sea buckthorn (Hippophaë rhamnoides) cultivars. The sensory profiles of the purees were dominated by intense sourness followed by astringency and bitterness due to the high content of malic acid. Malic acid and isorhamnetin glycosides, especially isorhamnetin-3-O-sophoroside-7-O-rhamnoside, had close association with the astringent attributes in the different purees, whereas some of the known astringent compounds such as proanthocyanidin dimers and trimers or quercetin glycosides, had less impact. Moreover, the ratios between contents of acids and phenolic compounds were more important predictors of bitterness than the individual variables alone. Astringency and bitterness are important sensory factors for the consumer acceptance of sea buckthorn products. The current study provides new knowledge on the correlations between sensory properties and composition and supports industrial utilization of the sea buckthorn berries.
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http://dx.doi.org/10.1021/acs.jafc.7b04156DOI Listing
November 2017

Fish Oil Finishing Diet Maintains Optimal n-3 Long-Chain Fatty Acid Content in European Whitefish (Coregonus lavaretus).

Lipids 2017 Oct 31;52(10):849-855. Epub 2017 Aug 31.

Natural Resources Institute Finland (Luke), Former Game and Fisheries Research Institute, 20520, Turku, Finland.

This study examined the effect of substituting vegetable oil for fish oil in feed, with subsequent re-introduction of fish oil-rich feed (finishing feeding) in late stages of growth, on the fatty acids of cultivated European whitefish (Coregonus lavaretus). Restorative finishing feeding with fish oil-rich feed for 15 and 25 weeks was sufficient to change the total content of nutritionally valuable long-chain n-3 fatty acids, eicosapentaenoic acid (20:5n-3) and docosahexaenoic acid (22:6n-3), to correspond to that of fish fed the fish oil-rich feed throughout their lifespan. Under natural conditions, 15 and 25 weeks correspond to weight gains of 75% and 100% (i.e. doubling), respectively. Also, the fatty acid profile of the fish was restored after finishing periods of 15 and 25 weeks. Limiting the use of fish oil by lowering the overall fat content of the feed (no vegetable oil added) resulted in a decrease in the long-chain n-3 fatty acids. Based on the results, after receiving a vegetable oil-rich diet, restorative fish oil-rich feeding in the last stages of growth in European whitefish is nutritionally justified in order to balance nutritional gain for consumers with sustainable use of finite marine oils. The results encourage commercial efforts to further utilize and optimize finishing feeding practices.
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http://dx.doi.org/10.1007/s11745-017-4290-xDOI Listing
October 2017

Triacylglycerol regioisomers in human milk resolved with an algorithmic novel electrospray ionization tandem mass spectrometry method.

Food Chem 2017 Oct 22;233:351-360. Epub 2017 Apr 22.

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

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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http://dx.doi.org/10.1016/j.foodchem.2017.04.122DOI Listing
October 2017

Sensory profile of ethyl β-d-glucopyranoside and its contribution to quality of sea buckthorn (Hippophaë rhamnoides L.).

Food Chem 2017 Oct 13;233:263-272. Epub 2017 Apr 13.

Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland; Department of Food Science and Engineering, Jinan University, 510632 Guangzhou, China. Electronic address:

The contribution of ethyl β-d-glucopyranoside (EG) to sensory profile of sea buckthorn (Hippophaë rhamnoides ssp. rhamnoides) was studied. The content of natural existing EG varied between 0.6 and 19.8g/L in the sea buckthorn studied. The taste threshold of pure EG was estimated in water solution as 1.1±1.3g/L, and the suprathreshold aqueous EG solution (5.0g/L) was perceived mainly as bitter. In aqueous sugar-acid mixtures, acids were the major contributors to sourness and astringency, whereas the added EG or sugars showed little impact on the overall sensory profile. EG addition increased the bitterness of sea buckthorn juice. The sensory profiles of the juices were dominated by intense sourness correlating with the malic acid content. The bitterness of the juices correlated with the EG content as well as the ratios EG/acids and EG/sugars. EG content shall be considered when selecting raw materials for industrial processing.
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http://dx.doi.org/10.1016/j.foodchem.2017.04.073DOI Listing
October 2017

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

Effect of processing technologies and storage conditions on stability of black currant juices with special focus on phenolic compounds and sensory properties.

Food Chem 2017 Apr 20;221:422-430. Epub 2016 Oct 20.

Food Chemistry and Food Development, Department of Biochemistry, University of Turku, FI-20014 Turku, Finland; Department of Food Science and Engineering, Jinan University, 510632 Guangzhou, China. Electronic address:

Juice was pressed from black currants without enzyme treatment (NEB=Non-Enzymatic Berry) followed by re-pressing of the residue with enzymes (EPR=Enzymatic Press Residue) and the results were compared to the conventional enzyme-aided berry pressing (EB=Enzymatic Berry). EPR-juice had 9- and 5-fold higher contents of phenolic compounds compared with the NEB- and EB-juices, respectively. Effect of the low content and stability of phenolics was noticed as loss of the visual color in the NEB-juice during storage. The decrease in monomeric anthocyanins and the increase in phenolic acids were most severe in the NEB-juice, whereas the most significant decline in hydroxycinnamic acid derivatives occurred in the enzyme-treated juices. Storage in light induced less change in the phenolic composition in EPR-juice than in the two other juices. The study gave new knowledge on changes in individual metabolites, in sensory properties and in the shelf life of berry juices.
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http://dx.doi.org/10.1016/j.foodchem.2016.10.079DOI Listing
April 2017

CO Plant Extracts Reduce Cholesterol Oxidation in Fish Patties during Cooking and Storage.

J Agric Food Chem 2016 Dec 15;64(51):9653-9662. Epub 2016 Dec 15.

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

Cholesterol oxidation products (COPs) in foods may pose risks for human health. Suitable antioxidants can reduce the formation of COPs in industrial products. Consumer awareness of food additives has brought a need for more natural alternatives. This is the first study on the effects of supercritical CO extracts of rosemary, oregano, and an antimicrobial blend of seven herbs, tested at two levels (1 and 3 g/kg fish), against cholesterol oxidation in patties made of a widely consumed fish species, Atlantic salmon (Salmo salar), during baking and storage. Cholesterol oxidation was reduced by the extracts as indicated by lowered levels of 7α-hydroxycholesterol, 7β-hydroxycholesterol, and 7-ketocholesterol, which were quantified by GC-MS. The total amount of COPs was smaller in all of the cooked samples containing the plant extracts (<1 μg/g extracted fat) than in the cooked control (14 μg/g). Furthermore, the plant extracts exhibited protective effects also during cold storage for up to 14 days.
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http://dx.doi.org/10.1021/acs.jafc.6b03655DOI Listing
December 2016

Phenolic compounds extracted by acidic aqueous ethanol from berries and leaves of different berry plants.

Food Chem 2017 Apr 22;220:266-281. Epub 2016 Sep 22.

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

Phenolic compounds of berries and leaves of thirteen various plant species were extracted with aqueous ethanol and analyzed with UPLC-DAD-ESI-MS, HPLC-DAD, and NMR. The total content of phenolics was consistently higher in leaves than in berries (25-7856 vs. 28-711mg/100g fresh weight). Sea buckthorn leaves were richest in phenolic compounds (7856mg/100g f.w.) with ellagitannins as the dominant compound class. Sea buckthorn berries contained mostly isorhamnetin glycosides, whereas quercetin glycosides were typically abundant in most samples investigated. Anthocyanins formed the dominating group of phenolics in most dark-colored berries but phenolic acid derivatives were equally abundant in saskatoon and chokeberry berries. Caffeoylquinic acids constituted 80% of the total phenolic content (1664mg/100g f.w.) in bilberry leaves. B-type procyanidins and caffeoylquinic acids were the major phenolic compounds in hawthorn and rowanberry, respectively. Use of leaves of some species with prunasin, tyramine and β-p-arbutin, may be limited in food applications.
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http://dx.doi.org/10.1016/j.foodchem.2016.09.145DOI Listing
April 2017

NMR metabolomics demonstrates phenotypic plasticity of sea buckthorn (Hippophaë rhamnoides) berries with respect to growth conditions in Finland and Canada.

Food Chem 2017 Mar 20;219:139-147. Epub 2016 Sep 20.

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

The berries of sea buckthorn (Hippophaë rhamnoides ssp. rhamnoides) cultivars 'Terhi' and 'Tytti' were studied with respect to their growth location, 60° and 68°N latitude in Finland and 46°N in Canada, using H NMR metabolomics. The berries of 'Terhi' were characterised by stronger signals of quinic acid, while 'Tytti' had higher levels of O-ethyl β-d-glucopyranoside. The metabolic profile of the northernmost berries was distinctly different from those grown in southern Finland or Canada. Berries from northern Finland had relatively higher levels of quinic acid, glucose, l-quebrachitol and ascorbic acid. Ethyl glucoside was shown to accumulate by several fold at the late stage of maturation in the south as it correlated with degree days (r=0.63) and global radiation (r=0.59), but not in the north. The variance in the composition of the sea buckthorn berries demonstrates plasticity in the acclimatisation to growth environments.
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http://dx.doi.org/10.1016/j.foodchem.2016.09.125DOI Listing
March 2017

Effects of latitude and weather conditions on proanthocyanidins in berries of Finnish wild and cultivated sea buckthorn (Hippophaë rhamnoides L. ssp. rhamnoides).

Food Chem 2017 Feb 12;216:87-96. Epub 2016 Aug 12.

Food Chemistry and Food Development, Department of Biochemistry, University of Turku, Finland; Department of Food Science and Engineering, Jinan University, 510632 Guangzhou, China. Electronic address:

Sea buckthorn (Hippophaë rhamnoides ssp. rhamnoides) of varieties 'Terhi' and 'Tytti' and one of wild origin were cultivated in southern and northern Finland, harvested during 2007-2013. Proanthocyanidins (PAs) were analyzed with HILIC UPLC-ESI-MS. The southern and northern samples were separated in the partial least squares discriminant analysis model (four factors, R(2) 0.75, Q(2) 0.70). The total PAs were more abundant in berries from the north (610-970mg/100gDW) than in those from the south (340-450mg/100gDW) (p<0.05). In northern Finland, the length of the growth season as well as the temperature sum and radiation sum of the growth season until harvest were negatively correlated with the total PAs in all the samples but positively with PA oligomers in 'Tytti' and 'Terhi'. In southern Finland no respective correlations were seen. 'Terhi' and 'Tytti' had different trends in the content of total PA and oligomers in overripe stages.
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http://dx.doi.org/10.1016/j.foodchem.2016.08.032DOI Listing
February 2017

Sea Buckthorn (Hippophaë rhamnoides ssp. rhamnoides) Berries in Nordic Environment: Compositional Response to Latitude and Weather Conditions.

J Agric Food Chem 2016 Jun 7;64(24):5031-44. Epub 2016 Jun 7.

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

Flavonol glycosides (FGs) in sea buckthorn (Hippophaë rhamnoides ssp. rhamnoides) berries of varieties 'Tytti' and 'Terhi', cultivated in northern Finland (68°02' N) for six years and southern Finland (60°23' N) for seven years, were investigated and compared by HPLC-DAD-ESI-MS/MS. The average total content of 23 identified glycosides of isorhamnetin and quercetin was 103 ± 23 and 110 ± 21 mg/100 g fresh berries in 'Terhi' and 'Tytti', respectively. The total contents of FGs, flavonol diglycosides, and triglycosides in both varieties were higher in the north than in the south, whereas total flavonol monoglycoside content behaved vice versa (p < 0.05). Among the 89 weather variables studied, the sum of the daily mean temperatures that are 5 °C or higher from the start of growth season until the day of harvest was the most important variable which associated negatively with the accumulation of FGs in berries. Such influence was much stronger in berries from the north than from the south.
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http://dx.doi.org/10.1021/acs.jafc.6b00682DOI Listing
June 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

Stability of Hydroxycinnamic Acid Derivatives, Flavonol Glycosides, and Anthocyanins in Black Currant Juice.

J Agric Food Chem 2016 Jun 26;64(22):4584-98. Epub 2016 May 26.

Department of Food Science and Engineering, Jinan University , 510632 Guangzhou, China.

The stability of phenolic compounds was followed in black currant juice at ambient temperatures (in light and in dark conditions) and at +4 °C for a year. Analyses were based on high-performance liquid chromatography-diode-array detection-electrospray ionization-mass spectrometry (or tandem mass spectrometry) and high-performance liquid chromatography-diode-array detection-electrospray ionization-quadrupole time-of-flight mass spectrometry methods supported by nuclear magnetic resonance after selective high-performance liquid chromatography isolation. Altogether, 43 metabolites were identified, of which 2-(Z)-p-coumaroyloxymethylene-4-β-d-glucopyranosyloxy-2-(Z)-butenenitrile, 2-(E)-caffeoyloxymethylene-4-β-d-glucopyranosyloxy-2-(Z)-butenenitrile, 1-O-(Z)-p-coumaroyl-β-d-glucopyranose, (Z)-p-coumaric acid 4-O-β-d-glucopyranoside, and (Z)-p-coumaric acid were novel findings in black currant juice. Hydroxycinnamic acid derivatives degraded 20-40% at room temperature during one year of storage, releasing free hydroxycinnamic acids. O-Glucosides of hydroxycinnamic acid compounds were the most stable, followed by O-acylquinic acids, acyloxymethyleneglucosyloxybutenenitriles, and O-acylglucoses. Light induced the isomerization of (E)-coumaric acid compounds into corresponding Z-isomers. Flavonol glycosides stayed fairly stable. Flavonol aglycones were derived mainly from malonylglucosides. Over 90% of anthocyanins were lost at room temperature in a year, practically independent of light. Storage at low temperatures, preferably excluding light, is necessary to retain the original composition of phenolic compounds.
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http://dx.doi.org/10.1021/acs.jafc.6b01005DOI Listing
June 2016

Flavonol glycosides in berries of two major subspecies of sea buckthorn (Hippophaë rhamnoides L.) and influence of growth sites.

Food Chem 2016 Jun 11;200:189-98. Epub 2016 Jan 11.

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

Flavonol glycosides of wild sea buckthorn (Hippophaë rhamnoides ssp. sinensis) berries from China and cultivated berries (H. rhamnoides ssp. mongolica) from Finland and Canada were identified and quantified. Twenty-six flavonol glycosides were found with isorhamnetin and quercetin as the major aglycones. The contents of flavonol glycosides ranged 23-250 mg/100 g fresh berries and were significantly higher in the berries of ssp. sinensis than in those of ssp. mongolica. Among the cultivars of ssp. mongolica, the berries of 'Oranzhevaya' had the lowest (23 mg/100 g) content, and those of 'Prevoshodnaya' the highest content of flavonol glycosides (80 mg/100 g). Within the ssp. mongolica, the samples from Kittilä (Northern Finland) had higher levels of most flavonol glycosides than those from Turku (Southern Finland) and Québec. Among the ssp. sinensis berries of different growth sites, increasing trends were detected in the contents of most of the compounds as the altitude increased and as the latitude decreased. The wild berries (ssp. sinensis) from Sichuan had remarkably high contents and unique profiles of flavonol glycosides.
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http://dx.doi.org/10.1016/j.foodchem.2016.01.036DOI Listing
June 2016

Proanthocyanidins in Sea Buckthorn (Hippophaë rhamnoides L.) Berries of Different Origins with Special Reference to the Influence of Genetic Background and Growth Location.

J Agric Food Chem 2016 Feb 2;64(6):1274-82. Epub 2016 Feb 2.

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

Wild sea buckthorn berries from Finland (Hippophaë rhamnoides ssp. rhamnoides) and China (ssp. sinensis) as well as berries of two varieties of ssp. rhamnoides cultivated in Finland and five of ssp. mongolica cultivated in Canada were compared on the basis of the content and composition of proanthocyanidins (PAs). Among all of the samples, only B-type PAs were found. The contents of dimeric, trimeric, tetrameric, and total PAs were in the range of 1.4-8.9, 1.3-9.5, 1.0-7.1, and 390-1940 mg/100 g of dry weight, respectively. The three subspecies were separated by three validated factors (R(2), 0.724; Q(2), 0.677) in the partial least squares discriminant analysis model. Significant differences in total PAs were found between the ssp. rhamnoides and mongolica samples (p < 0.05). In ssp. rhamnoides, samples grown in northern Finland were characterized by a high amount of total PAs, typically 2-3 times higher than that in the level found in southern Finland. In ssp. sinensis, altitude did not have a systematic effect on the PA composition, suggesting the significance of the interaction between genetic background and growth location.
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http://dx.doi.org/10.1021/acs.jafc.5b05718DOI Listing
February 2016
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