| 1. |
- Alström, Sadhna, et al.
(författare)
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Chromatographic profiling of hydrophilic metabolites from tubers of different potato cultivars
- 2009
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Konferensbidrag (refereegranskat)abstract
- Potato is an important source of nutrients and bioactive compounds with profitable effect for health, such as antioxidants, vitamins and essential amino acids. The knowledge about metabolite composition of various potato cultivars is necessary to facilitate development of new cultivars with desirable properties. In the present study, the hydrophilic metabolite composition of six potato cultivars with different resistance against potato late blight disease was analyzed. For this, an HPLC-based method was developed and used for the analysis of water-ethanol extracts of freeze-dried potato tubers. Significant differences in concentrations of adenosine, chlorogenic acid, and rutin were revealed. Some other metabolites were found to be cultivar-specific
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| 2. |
- Andlid, Thomas, 1963, et al.
(författare)
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Folate and Bifidobacteria
- 2018
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Ingår i: The Bifidobacteria and Related Organisms: Biology, Taxonomy, Applications. - 9780128050606 ; , s. 195-212
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Bokkapitel (övrigt vetenskapligt/konstnärligt)abstract
- Folate is the generic term for a group of chemically related and biologically active forms of vitamin B9, needed by all organisms. Folic acid is the fully oxidized synthetic form of the vitamin. The chapter starts with nomenclature and chemical structure of folate forms followed by methodologies for extraction and chemical analysis of bacterial folate. Folates are unstable and susceptible to interconversion reactions so the special care needed to correctly determine folates in bacteria is discussed. Next follows folate biosynthesis, which happens commonly in plants and many microbes, including most bifidobacteria, but is absent in mammals, such as humans. Relevant genes, enzymes, and intermediate metabolites are described. Thereafter, the chapter continues to review folate metabolism, which describes cycling of different one-carbon units, using folate as vehicle, necessary for, for example, nucleic acid biosynthesis (purines and thymidine), amino acid homeostasis (glycine, serine, and methionine), and methylation of macromolecules, such as proteins and DNA, which includes epigenetic maintenance. Next follows a section on how biotechnology can be applied to produce high levels of microbial folate, to be used either as a food additive or as folate-producing probiotics. Finally, the main concerns and health implications from insufficient folate intake are described.
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| 3. |
- Broberg, Anders, et al.
(författare)
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Content of antioxidant hydroquinones substituted by beta-1,6-linked oligosaccharides in wheat milled fractions, flours and breads
- 2010
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Ingår i: Food Chemistry. - : Elsevier BV. - 0308-8146 .- 1873-7072. ; 121, s. 645-652
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Tidskriftsartikel (refereegranskat)abstract
- The objective of this study was to quantify seven antioxidant hydroquinones, substituted by beta-1,6-linked oligosaccharides, in wheat-based food products by HPLC. These novel compounds were discovered and characterised in our previous study. All seven compounds were quantified in wheat germ and bran. The most abundant compound, 4-hydroxy-3-methoxyphenyl beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranoside, was present at 6.3 g/kg in germ and 0.7 g/kg in bran. In whole-wheat grains, as well as in several kinds of wheat flour and wheat bread, these antioxidants were present at much lower concentrations; only two of them could be quantified. None of these compounds were detected in low-protein flour mixture. Their total content in analysed wheat products decreased in the following order: germ > bran > whole grains similar to whole grain flours > refined flours > refined bread >> low-protein flour mixture. It correlated well with the antioxidant capacity of water-ethanol extracts of these products determined by Trolox equivalent antioxidant capacity (TEAC) assay (r(2) = 0.984). The contribution of the analysed compounds to the total antioxidant capacity of wheat germ extract was 52%, whereas the contribution of the most abundant compound was 38%. (C) 2010 Elsevier Ltd. All rights reserved.
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| 4. |
- Dimberg, Lena, et al.
(författare)
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Quantitative analysis of oat avenanthramides
- 2009
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Ingår i: HEALTHGRAIN Methods : analysis of bioactive components in small grain cereals. - 9781891127700 ; , s. 113-128
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Bokkapitel (övrigt vetenskapligt/konstnärligt)
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| 5. |
- Hjortmo, Sofia, 1978, et al.
(författare)
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Biofortification of folates in white wheat bread by selection of yeast strain and process
- 2008
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Ingår i: International Journal of Food Microbiology. - : Elsevier BV. - 1879-3460 .- 0168-1605. ; 127:1-2, s. 32-36
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Tidskriftsartikel (refereegranskat)abstract
- We here demonstrate that folate content in yeast fermented food can be dramatically increased by using a proper (i) yeast strain and (ii) cultivation procedure for the selected strain prior to food fermentation. Folate levels were 3 to 5-fold higher in white wheat bread leavened with a Saccharomyces cerevisiae strain CBS7764, cultured in defined medium and harvested in the respiro-fermentative phase of growth prior to dough preparation (135-139 mu g/100 dry matter), compared to white wheat bread leavened with commercial Baker's yeast (27-43 mu g/100 g). The commercial Baker's yeast strain had been industrially produced, using a fedbatch process. thereafter compressed and stored in the refrigerator until bakings were initiated. This strategy is an attractive alternative to fortification of bread with synthetically produced folic acid. By using a high folate producing strain cultured a suitable way folate levels obtained were in accordance with folic acid content in fortified cereal products.
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| 6. |
- Hjortmo, Sofia, 1978, et al.
(författare)
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Inherent biodiversity of folate content and composition in yeasts
- 2005
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Ingår i: Trends in Food Science and Technology. - : Elsevier BV. - 0924-2244. ; 16:6-7, s. 311-316
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Tidskriftsartikel (refereegranskat)abstract
- We have studied folate content and composition in 44 yeast strains cultivated in a synthetic medium at standardised conditions. Folates were measured by a validated HPLC method. The total folate content ranged from 4000 to 14,500 mu g/100g dry matter showing a large biodiversity among studied yeasts. The forms found were 5-CH3-H(4)folate and H(4)folate, also varying extensively in relative amounts between different strains. Several strains showed a showed two-fold or higher folate content as compared to the control strain-a commercial strain of Baker's yeast. This indicates that folate content in yeast-fermented foods may be more than doubled merely by choosing a proper strain.
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| 7. |
- Jastrebova, Jelena, et al.
(författare)
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Antioxidant Hydroquinones Substituted by beta-1,6-Linked Oligosaccharides in Wheat Germ
- 2009
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Ingår i: Journal of Natural Products. - : American Chemical Society (ACS). - 0163-3864 .- 1520-6025. ; 72, s. 656-661
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Tidskriftsartikel (refereegranskat)abstract
- Seven new compounds that demonstrate antioxidant properties, 4-hydroxy-3-methoxyphenyl beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranoside (1), 4-hydroxyphenyl beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranoside (2), 4-hydroxy-3-methoxyphenyl-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranoside (3), 4-hydroxy-3-methoxyphenyl-D-glucopyranosyl-(1 -> 6)-beta-Dglucopyranoside (4), 4-hydroxy-3,5-dimethoxyphenyl beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranoside (5), 4-hydroxy-3,5-dimethoxyphenyl-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranoside (6), and 4-hydroxy-2-methoxyphenyl-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranosyl-(1 -> 6)-beta-D-glucopyranoside (7), were isolated from wheat germ. The structures were determined by spectroscopic and chemical methods. Compound I was the most abundant, similar to 2 mg isolated from each gram of wheat germ. The antioxidant activity of compounds 1-7 was determined by the Trolox equivalent antioxidant capacity assay, and 2 and 7 showed higher values than the other compounds. Compounds 1 and 3-6 reacted with the radical cation reagent within a few seconds, whereas 2 and 7 required several minutes for complete reaction. Compound 1 was shown to protect plasmid DNA from oxidative stress damage caused by hydrogen peroxide; this effect was concentration-dependent.
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| 8. |
- Jastrebova, Jelena, et al.
(författare)
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Comparison of UPLC and HPLC for Analysis of Dietary Folates
- 2011
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Ingår i: Chromatographia. - : Springer Science and Business Media LLC. - 0009-5893 .- 1612-1112. ; 73, s. 219-225
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Tidskriftsartikel (refereegranskat)abstract
- Ultra performance liquid chromatography (UPLC) using small sub-2 mu m particles and high performance liquid chromatography (HPLC) were compared for separation and determination of the most common dietary folates; 5-methyltetrahydrofolate, tetrahydrofolate, 5-formyltetrahydrofolate, 10-formylfolic acid and folic acid. Two UPLC columns-Acquity BEH C(18) and Acquity HSS T3, and two HPLC columns with similar surface chemistry-Xbridge C(18) and Atlantis d18 were tested. When using UPLC, the signal-to-noise ratio could be improved by a factor of 2-50 for different folate derivatives and the run time could be reduced fourfold without sacrificing separation efficiency. The applicability of UPLC to real food samples was demonstrated
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| 9. |
- Jastrebova, Jelena
(författare)
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Folate content in Swedish eggs: influence of breed, feed and processing
- 2011
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Ingår i: European Food Research and Technology. - : Springer Science and Business Media LLC. - 1438-2377 .- 1438-2385. ; 233, s. 923-930
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Tidskriftsartikel (refereegranskat)abstract
- Folate content in eggs from three different breeds of hens fed with three different feeds, one organic and two conventional, was compared using a simplified microbiological assay. Retention of folate when boiling the eggs was also studied. Folate content in eggs did not differ significantly due to the breed of hen or the feed used. The loss of folate when boiling the eggs was 9%. The results from the microbiological assay were confirmed by LC/MS. According to this study, 1 egg (60 g) provides 40-50 mu g of folate. This corresponds to 13-17% of the recommended daily intake, 300 mu g for adults in the Nordic Nutrition Recommendations. The folate forms found in egg yolk with LC/MS were 5-methyl-tetrahydrofolate and 10-formyl-folic acid, whereas no folates were found in egg white. In this study, no polyglutamate folate forms could be detected in eggs.
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| 10. |
- Jastrebova, Jelena, et al.
(författare)
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HPLC determination of folates in raw and processed beetroots
- 2003
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Ingår i: Food Chemistry. - 0308-8146 .- 1873-7072. ; 80:4, s. 579-588
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Tidskriftsartikel (refereegranskat)abstract
- A sensitive HPLC method with fluorescence detection and gradient elution has been developed for the determination of folates in vegetables. The method involved extraction of folates from food matrix by heat treatment, deconjugation of folate polyglutamates to monoglutamates by incubation with hog kidney conjugase and purification of food extracts by solid-phase extraction with strong-anion exchange cartridges. The chromatographic separation of folates was achieved on Zorbax SB C-8 column, which was found to be superior over conventional C-18 column in terms of selectivity and sensitivity. Validation of the method included linearity tests, the addition of standard folates for the determination of recovery, repeatability and stability tests. The method developed was applied to analysis of raw and processed beetroots; 5-methyltetrahydrofolate was found to be the main folate form in beetroots. Cultivar differences and growing conditions were found to have a pronounced effect on the folate content in beetroots. Processing resulted in considerable losses of folates, whereas losses during storage appeared to be moderate.
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