Remember Me
Or use your Academic/Social account:


Or use your Academic/Social account:


You have just completed your registration at OpenAire.

Before you can login to the site, you will need to activate your account. An e-mail will be sent to you with the proper instructions.


Please note that this site is currently undergoing Beta testing.
Any new content you create is not guaranteed to be present to the final version of the site upon release.

Thank you for your patience,
OpenAire Dev Team.

Close This Message


Verify Password:
Verify E-mail:
*All Fields Are Required.
Please Verify You Are Human:
fbtwitterlinkedinvimeoflicker grey 14rssslideshare1
Johansson, Madelene; Jägerstad, Margaretha; Frølich, Wenche (2007)
Publisher: Co-Action Publishing
Journal: Food & Nutrition Research
Languages: English
Types: Article
Subjects: Original Article, leafy vegetables, HPLC, LC-MS, folate analysis, storage, folate retention
Background: Leafy vegetables are good sources of folates and food shops nowadays offer an increasing number of lettuce varieties. Objective: To obtain data on the folate content and forms in common lettuce varieties and spinach sold in the Nordic countries, and to investigate effects of different storage conditions and preparations in the consumer’s home or at lunchtime restaurants. Design: Folate was analysed in eight different lettuce varieties and spinach using a validated high-performance liquid chromatographic method and the detected forms of folates were confirmed by a mass spectrometric detector [liquid chromatography-mass spectrometry (LC-MS)] following heat extraction, deconjugation with rat serum and purification by solid-phase extraction. Results: Folate content, expressed in folic acid equivalents, in the lettuce samples varied six-fold, from 30 to 198µg 100 g-1 on a fresh weight basis. The folate content was decreased by 14% after storage at 48°C f or 8 days and by 2-40% after storage at 22°C for 2-4 h, depending on whether samples were stored as whole leaves, or small torn or cut pieces. LC-MS confirmed the identity of the folate forms: H4folate, 5-CH3- H4folate, 5-HCO-H4folate and 10-HCO-H4folate. Conclusion: The considerable variation in folate content between varieties of lettuce in this pilot study, with one variety reaching the level found in spinach, indicates the potential to increase folate intake considerably by choosing folate-rich varieties of lettuce and storing at low temperatures. Keywords: folate analysis; folate retention; HPLC, LC-MS; leafy vegetables; storage
  • The results below are discovered through our pilot algorithms. Let us know how we are doing!

    • 1. Simila¨ M, Fagt S, Vaask S, Thorgeirsdottir H, Padule I, Petkeviciene J, et al. The NORBAGREEN 2002 study. Copenhagen: Nordic Council of Ministers; 2003.
    • 2. Anon. WHO TRS 916. Diet, nutrition and the prevention of chronic diseases. Report from a joint FAO/WHO Expert Consultation. Geneva: World Health Organization; 2003.
    • 3. NNR, Nordic Nutrition Recommendations 2004, Nord 2004:13, 4th edn. Copenhagen: Nordic Council of Ministers; 2004.
    • 4. Bailey LB, Rampersaud GC, Kauwell GPA. Folic acid supplements and fortification affect the risk for neural tube defects, vascular disease and cancer: evolving science. J Nutr 2003; 133: 1961 8S.
    • 5. Boushey CJ, Beresford SA, Omenn GS, Motulsky AG. A quantitative assessment of plasma homocysteine as a risk factor for vascular disease. JAMA 1995; 274: 1049 57.
    • 6. de Bree A, van Dusseldorp M, Brouwer IA, van het Hof KH, Steegers-Theunissen RPM. Folate intake in Europe: recommended, actual and desired intake. Eur J Clin Nutr 1997; 51: 643 60.
    • 7. Chen T-S, Song Y-O, Kirsch AJ. Effects of blanching, freezing and storage on folacin contents of spinach. Nutr Rep Int 1983; 28: 317 23.
    • 8. Pandrangi S, LaBorde LF. Retention of folate, carotenoids, and other quality characteristics in commercially packaged fresh spinach. J Food Sci 2004; 69: C702 7.
    • 9. Mullin WJ, Wood DF, Howsam SG. Some factors affecting folacin content of spinach, Swiss chard, broccoli and brussels sprouts. Nutr Rep Int 1982; 26: 7 16.
    • 10. Gami DB, Chen T-S. Kinetics of folacin destruction in Swiss chard during storage. J Food Sci 1985; 50: 447 9.
    • 11. Zhang GF, Storozhenko S, van der Straeten D, Lambert WE. Investigation of the extraction behaviour of the main monoglutamate folates from spinach by liquid chromatography electrospray ionization tandem mass spectrometry. J Chromatogr A 2005; 1078: 59 66.
    • 12. Patring JDM, Jastrebova JA, Hjortmo SB, Andlid T, Ja¨gerstad MI. Development of a simplified method for simultaneous determination of folates in bakers' yeast by liquid chromatography with ultraviolet and fluorescence detection. J Agric Food Chem 2005; 53: 2406 11.
    • 13. Pfeiffer CM, Rogers LM, Bailey LB, Gregory JF. Absorption of folate from fortified cereal-grain products and of supplemental folate consumed with or without food determined using a dual-label stable-isotope protocol. Am J Clin Nutr 1997; 66: 1388 97.
    • 14. Holte Stea T, Johansson M, Ja¨gerstad M, Frølich W. Retention of folates in cooked, stored and reheated peas, broccoli and potatoes for use in modern large-scale service systems. Food Chem 2006; 101: 1095 107.
    • 15. AOAC. Official methods of analysis. In: Horwitz W, ed. AOAC official method 992.05 folic acid (pteroylglutamic acid) in infant formula. Vol 2. 17th ed. Gaithersburg, MD: AOAC International; 2000:50.024 50.6.
    • 16. Nilsson C, Johansson M, Yazynina E, Stra˚lsjo¨ L, Jastrebova J. Solid-phase extraction for HPLC analysis of dietary folates. Eur Food Res Technol 2004; 219: 199 204.
    • 17. Patring JDH, Jastrebova JA. Application of liquid chromatography electrospray ionisation mass spectrometry for determination of dietary folates: Effects of buffer nature and mobile phase composition on sensitivity and selectivity. J Chromatogr A 2007; 1143: 72 82.
    • 18. Freisleben A, Schieberle P, Rychlik M. Specific and sensitive quantification of folate vitamers in foods by stable isotope dilution assays using high-performance liquid chromatography tandem mass spectrometry. Anal Bioanal Chem 2003; 376: 149 56.
    • 19. Konings EJ, Roomans HH, Dorant E, Goldbohm RA, Saris WH, van den Brandt PA. Folate intake of the Dutch population according to newly established liquid chromatography data for foods. Am J Clin Nutr 2001; 73: 765 76.
    • 20. SLV. Food composition table energy and nutrients. Uppsala: SLV; 2002.
    • 21. Fineli. Finnish food composition database. Helsinki: Finnish Public Health Institute, Nutrition Unit; 2004.
    • 22. Møller A, Saxholt E, Christensen AT, Hartkopp HB, Hess Ygil K. Danish food composition databank, revision 6.0. Department of Nutrition, Danish Institute for Food and Veterinary Research; 2005 (http:// www.foodcomp.dk/:Food Informatics).
    • 23. Patring JDM, Johansson MS, Yazynina E, Jastrebova JA. Evaluation of impact of different antioxidants on stability of dietary folates during food sample preparation and storage of extracts prior to analysis. Anal Chim Acta 2005; 553: 36 42.
    • 24. Shrestha AK, Arcot J, Paterson J. Folate assay of food by traditional and tri-enzyme treatments using cryoprotected Lactobacillus casei . Food Chem 2000; 71: 545 52.
    • 25. Simonne A, Simonne E, Eitenmiller R, Coker CH. Bitterness and composition of lettuce varieties grown in the southeastern United States. Horttechnology 2002; 12: 721 6.
  • No related research data.
  • No similar publications.

Share - Bookmark

Cite this article