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  • 51. Strålsjö, Lena M
    et al.
    Witthöft, Cornelia M.
    Sveriges lantbruksuniversitet, Uppsala.
    Sjöholm, Ingegerd M
    Jägerstad, Margaretha I
    Folate content in strawberries (Fragaria x ananassa): effects of cultivar, ripeness, year of harvest, storage, and commercial processing.2003In: Journal of Agricultural and Food Chemistry, ISSN 0021-8561, E-ISSN 1520-5118, Vol. 51, no 1, p. 128-133Article in journal (Refereed)
    Abstract [en]

    Folate concentrations in strawberries and folate retention during storage and commercial processing of strawberries were investigated. No previous study has focused on the effects of cultivar, ripeness, and year of harvest of strawberries with respect to the folate content. This study showed the folate concentration in strawberries to significantly depend on all of these different factors. Total folate was quantified using a modified and validated radioprotein-binding assay with external calibration (5-CH(3)-H(4)folate). Folate content in 13 different strawberry cultivars varied from 335 microg/100 g of dry matter (DM) for cv. Senga Sengana to 644 microg/100 g of DM for cv. Elsanta. Swedish harvests from 1999 and 2001 yielded higher folate concentrations than did the harvest from 2000, and the grade of ripeness affected the folate content in strawberries. This study indicated high folate retention in intact berries during storage until 3 or 9 days at 4 degrees C (71-99%) and also in most tested commercial products (79-103%). On the basis of these data fresh strawberries as well as processed strawberry products are recommended to be good folate sources. For instance, 250 g (fresh weight) of strawberries ( approximately 125 microg of folate) supplies approximately 50% of the recommended daily folate intake in various European countries (200-300 microg/day) or 30% of the U.S. recommendation (400 microg/day).

  • 52.
    Strålsjö, Lena
    et al.
    Swedish University of Agricultural Science.
    Åhlin, Hanna
    Swedish University of Agricultural Science.
    Witthöft, Cornelia M.
    Swedish University of Agricultural Science.
    Jastrebova, Jelena
    Swedish University of Agricultural Science.
    Folate determination in Swedish berries by radioprotein-binding assay (RPBA) and high performance liquid chromatography (HPLC)2003In: European Food Research and Technology, ISSN 1438-2377, E-ISSN 1438-2385, Vol. 216, no 3, p. 264-269Article in journal (Refereed)
    Abstract [en]

    Folate content in berries and the effect of cultivar on folate content in strawberries were investigated using a modified radioprotein-binding assay (RPBA) combined with solid phase extraction (SPE). With an SPE step prior to quantification the matrix effects in the RPBA assay were minimised. HPLC quantification was used to compare and characterise individual folate forms. High correlation (r = 0.9796) was shown and the mean difference between the RPBA and HPLC method was 6.7 4.8 mug/100 g. The predominating folate form was 6S-5-CH3-H-4-folate in all tested berries (>95%). Therefore, this biologically active folate form (6S-5-CH3-H(4)folate) must be chosen as calibrant because the RPBA response of the synthetic equimolar mixture of R- and S-diastereomers (6R,S-5-CH3-H(4)folate) was considerably higher, about 30%. The folate content in nine selected Swedish berries varied from 11 to 96 mug/100 g (fresh weight) and the highest folate content was found in rose hips (96 mug/100 g) and strawberries (74 mug/100 g). Moderate folate sources were raspberry (46 mug/100 g) and sea buckthorn (39 mug/100 g), whereas all other tested berries contained about 20 mug of folate/100 g or less. In strawberries, folate content varied significantly among eight different cultivars from 73 mug/100 g (Lina) to 99 mug/100 g (Melody).

  • 53.
    Svensén, Katarina
    Linnaeus University, Faculty of Science and Engineering, School of Engineering.
    Ekologisk mat: - Hur kan lärare på gymnsieskolans hotell- och restaurangutbildning jobba med en omställning från konventionellt till ekologiskt2010Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
  • 54. Vahteristo, L
    et al.
    Finglas, P M
    Witthöft, Cornelia M.
    Justus Liebig-Universität, Germany.
    Wigertz, K
    Seale, R
    deFroidmontGortz, I
    Third EU MAT intercomparison study on food folate analysis using HPLC procedures1996In: Food Chemistry, ISSN 0308-8146, E-ISSN 1873-7072, Vol. 57, no 1, p. 109-111Article in journal (Refereed)
    Abstract [en]

    Three samples (milk powder, lyophilized pig's liver and wholemeal flour), a 5-methyltetrahydrofolic acid (5-MTHF) calibrant and two deconjugase enzymes (purified hog kidney and human plasma) were circulated to three laboratories taking part in the study. The objectives were to optimize the deconjugation step in these foods and to improve the between-laboratory agreement in HPLC results for folates. The predominant natural folate form in milk powder was 5-MTHF, together with appreciable amounts of folic acid. In pig's liver 5-MTHF was found to represent about one-third of the total folate content found. For these two foods, results from one laboratory of the sum of the folate vitamers agreed favourably with the microbiological data. 5-MTHF was most successfully determined by all three laboratories. There was little or no agreement found for the other folate vitamers detected. Copyright (C) 1996 Elsevier Science Ltd

  • 55. Van Guelpen, Bethany
    et al.
    Hultdin, Johan
    Johansson, Ingegerd
    Stegmayr, Birgitta
    Hallmans, Göran
    Nilsson, Torbjörn K
    Weinehall, Lars
    Witthöft, Cornelia M.
    Sveriges lantbruksuniversitet, Uppsala.
    Palmqvist, Richard
    Winkvist, Anna
    Folate, vitamin B12, and risk of ischemic and hemorrhagic stroke: a prospective, nested case-referent study of plasma concentrations and dietary intake.2005In: Stroke, ISSN 0039-2499, E-ISSN 1524-4628, Vol. 36, no 7, p. 1426-1431Article in journal (Refereed)
    Abstract [en]

    BACKGROUND AND PURPOSE: Folate metabolism has been implicated in stroke. However, the possibility of a role for folate and vitamin B12, independent of their effects on homocysteine status, remains to be explored. The aim of this prospective, nested case-referent study was to relate plasma and dietary intake levels of folate and vitamin B12 to risk of stroke, taking into consideration plasma homocysteine concentrations and methylenetetrahydrofolate reductase polymorphisms.

    METHODS: Subjects were 334 ischemic and 62 hemorrhagic stroke cases and matched double referents from the population-based Northern Sweden Health and Disease Cohort.

    RESULTS: Plasma folate was statistically significantly associated with risk of hemorrhagic stroke in an inverse linear manner, both in univariate analysis and after adjustment for conventional risk factors including hypertension (odds ratio [OR] for highest versus lowest quartile 0.21 (95% confidence interval [CI], 0.06 to 0.71; P for trend=0.008)). Risk estimates were attenuated by inclusion of homocysteine in the model (OR, 0.34; 95% CI, 0.08 to 1.40; P for trend=0.088). A similar pattern was observed for increasing folate intake (multivariate OR, 0.07; 95% CI, 0.01 to 0.55; P for trend=0.031 without homocysteine, and OR, 0.16, 95% CI, 0.02 to 1.23; P for trend=0.118 with homocysteine in the analysis). We found little evidence of an association between plasma or dietary folate and risk of ischemic stroke. Neither plasma nor dietary vitamin B12 was associated with risk of either stroke subtype.

    CONCLUSIONS: The results of this study suggest a protective role for folate, possibly in addition to its effects on homocysteine status, in hemorrhagic but not ischemic stroke.

  • 56. Verwei, M
    et al.
    Arkbåge, K
    Groten, J P
    Witthöft, Cornelia M.
    Swedish University of Agricultural Sciences.
    VandenBerg, H
    Havenaar, R
    The effect of folatebinding proteins on bioavailability of folate from milk products2005In: Trends in Food Science & Technology, ISSN 0924-2244, E-ISSN 1879-3053, Vol. 16, no 6-7, p. 307-310Article in journal (Refereed)
  • 57. Verwei, Miriam
    et al.
    Arkbåge, Karin
    Havenaar, Robert
    van den Berg, Henk
    Schaafsma, Gertjan
    SLU.
    Witthöft, Cornelia M.
    Sveriges lantbruksuniversitet, Uppsala.
    Folic acid and 5-methyltetrahydrofolate in fortified milk are bioaccessible as determined in a dynamic in vitro gastrointestinal model.2003In: Journal of Nutrition, ISSN 0022-3166, E-ISSN 1541-6100, Vol. 133, no 7, p. 2377-2383Article in journal (Refereed)
    Abstract [en]

    Dairy products are a potential matrix for folate fortification to enhance folate consumption in the Western world. Milk folate-binding proteins (FBP) are especially interesting because they seem to be involved in folate bioavailability. In this study, folate bioaccessibility was investigated using a dynamic computer-controlled gastrointestinal model [TNO gastrointestinal model (TIM)]. We used both ultrahigh temperature (UHT)-processed milk and pasteurized milk, differing in endogenous FBP concentrations and fortified with folic acid or 5-methyltetrahydrofolate (5-CH(3)-H(4)folate). To study FBP stability during gastrointestinal passage and the effect of additional FBP on folate bioaccessibility, FBP-fortified UHT and pasteurized milk products were also tested. Folate bioaccessibility and FBP stability were measured by taking samples along the compartments of the gastrointestinal model and measuring their folate and FBP concentrations. Folate bioaccessibility from folic acid-fortified milk products without additional FBP was 58-61%. This was lower (P < 0.05) than that of the 5-CH(3)-H(4)folate-fortified milk products (71%). Addition of FBP reduced (P < 0.05) folate bioaccessibility from folic acid-fortified milk (44-51%) but not from 5-CH(3)-H(4)folate-fortified milk products (72%). The residual FBP levels in the folic acid- and 5-CH(3)-H(4)folate-fortified milk products after gastrointestinal passage were 13-16% and 0-1%, respectively, of the starting amounts subjected to TIM. In conclusion, milk seems to be a suitable carrier for folate, because both folic acid and 5-CH(3)-H(4)folate are easily released from the matrix and available for absorption. However, our results suggest that folic acid remains partly bound to FBP during passage through the small intestine, which reduces the bioaccessibility of folic acid from milk in this model.

  • 58.
    Witten, Thomas
    Växjö University, Faculty of Mathematics/Science/Technology, School of Technology and Design.
    En lättviktsskiva i massivt trä för möbelindustrin2006Independent thesis Basic level (professional degree), 10 credits / 15 HE creditsStudent thesis
    Abstract [en]

    Light-weight panels to the furniture industry have been a well documented task in line papers the last

    time. This work describes and studies a new type of a construction of a light-weight panel in massive

    wood. The light-weight panel in massive wood is built like a sandwich construction in three levels. The

    outer layers are made of 6 mm thick massive wood glue panels and the core material by profiled

    distances. Material is pine and the light-weight panel has a density of 310–332 kg/m3. Out of contacts

    with selected producers and users of board materials, as in combination with tests, has this construction

    been checked and purposes for improvements have been stated. The original distances, which were put

    together by two parts including a centre hole have been replaced by a type of distance in massive wood

    with a similar profiling. In contacts with companies has a slightly reserve been shown to finger-joints

    on visible surfaces, which the originally prototype had. I conclusion with this presents a suggestion for

    different kinds of qualities for visible and not visible respectively and hidden surfaces in conclusion

    with the investigation of aesthetically and production technically aspects.

  • 59.
    Witthöft, Cornelia M.
    Swedish University of Agricultural Sciences.
    Analytical Methods to Assess the Bioavailability of Water-Soluble Vitamins in Food: Exemplified by Folate2011In: Fortified Foods with Vitamins: Analytical Concepts to Assure Better and Safer Products / [ed] Michael Rychlik, Wiley-VCH Verlagsgesellschaft, 2011, 1, p. 21-36Chapter in book (Other academic)
    Abstract [en]

    This chapter reviews briefly analytical methods and models for the determination of in vivo folate bioavailability. Advantages and limitations of models are discussed and recent data on the bioavailability of native food folates and folic acid fortificant are summarized.

  • 60.
    Witthöft, Cornelia M.
    Sveriges lantbruksuniversitet, Uppsala.
    Vitamins: Folates2011In: Encyclopedia of Dairy Sciences / [ed] John W. Fuquay; Patrick F. Fox; Paul L. H. McSweeney, Academic Press, 2011, 2, p. 678-686Chapter in book (Other academic)
    Abstract [en]

    Folate is one of the water-soluble B-vitamins and is an essential micronutrient required as a coenzyme in the human body’s one-carbon metabolism. A good folate status is linked to several health benefits, for example, reduced risk for neural tube defects, other malformations during pregnancy, and coronary heart disease. Leafy green vegetables are rich in folate, while dairy products are considered as only moderate folate sources. Processing and storage can affect folate content. The average intake of dietary folate, as epidemiologic data show, is half the recommendation in countries with no mandatory fortification policy. This article aims to briefly present the chemistry, physiological functions, and health-protective role of folates. A short overview on analytical methods is given. Thereafter, data on the folate content of milk and dairy products are presented, and the effects of processing are discussed briefly. With emphasis to dairy products, research findings in connection with folate bioavailability and folic acid fortification are summarized.

  • 61.
    Witthöft, Cornelia M.
    et al.
    Sveriges lantbruksuniversitet, Uppsala.
    Arkbåge, Karin
    Johansson, Madelene
    Lundin, Eva
    Berglund, Gerd
    Zhang, Jie-Xian
    Lennernäs, Hans
    Dainty, Jack R
    Folate absorption from folate-fortified and processed foods using a human ileostomy model.2006In: British Journal of Nutrition, ISSN 0007-1145, E-ISSN 1475-2662, Vol. 95, no 1, p. 181-187Article in journal (Refereed)
    Abstract [en]

    Data on folate absorption from food from validated human studies using physiological folate doses are still needed to estimate dietary requirements and to formulate recommendations. The aim of the present work was to study the effects from fortified and processed foods on folate absorption in ileostomy volunteers (n 9) using the area under the plasma concentration curve (AUC) and kinetic modelling. Using a standardized single-dose protocol, dairy products fortified with a candidate fortificant (6S)-5-methyltetrahydrofolate ((6S)-5-CH3-H4folate), folic acid-fortified bread and a dessert crème containing natural yeast folate polyglutamates were compared with folate supplements. Absorbed folate was estimated by AUC and a kinetic model, and non-absorbed folate by ileostomal folate excretion. Median apparent absorption from test foods ranged from 55 to 86 %. Added folate-binding proteins (FBP) significantly reduced folate absorption from dairy products, as in the absence of FBP, AUC-dose-corrected ratios were increased and ileal folate excretion decreased. After in vivo gastrointestinal passage of dairy products containing FBP, up to 43 % of the ingested FBP was found in ileostomal effluent. Folate absorption was similar for (6S)-5-CH3-H4folate fortificant from fermented milk and for folic acid from fortified bread. Folic acid, ingested as food fortificant in bread, was significantly less absorbed compared with an isolated supplement. We conclude that all tested foods were suitable matrices for folate fortification. However, dairy products, fortified with the new candidate fortificant (6S)-5-CH3-H4folate, are suitable if no active FBP is present.

  • 62.
    Witthöft, Cornelia M.
    et al.
    Linnaeus University, Faculty of Health and Life Sciences, Department of Chemistry and Biomedical Sciences.
    Hefni, Mohammed E.
    Mansoura University, Egypt.
    Folic acid and Folates: Physiology and Health Effects2016In: The Encyclopedia of Food and Health / [ed] Caballero, B., Finglas, P., and Toldrá, F., Elsevier, 2016, 1, p. 724-730Chapter in book (Refereed)
    Abstract [en]

    This article reviews briefly information regarding important food sources for folate, effects from storage and processing on folate content, and bioprocessing techniques that could provide foods with increased folate content. Thereafter, folate intake, absorption, metabolism, and bioavailability are also discussed. Finally, health effects associated with folate are presented briefly.

  • 63.
    Witthöft, Cornelia M.
    et al.
    Swedish Univ Agr Sci.
    Hefni, Mohammed E.
    Mansoura Univ, Egypt.
    Moazzami, Ali
    Swedish Univ Agr Sci.
    Folic acid supplement induces changes in 1-carbon metabolism of healthy women compared to food folate2015In: Annals of Nutrition and Metabolism, ISSN 0250-6807, E-ISSN 1421-9697, Vol. 67, p. 248-248Article in journal (Refereed)
  • 64. Öhrvik, Veronica E
    et al.
    Büttner, Barbara E
    Rychlik, Michael
    Lundin, Eva
    Witthöft, Cornelia M.
    Sveriges lantbruksuniversitet, Uppsala.
    Folate bioavailability from breads and a meal assessed with a human stable-isotope area under the curve and ileostomy model.2010In: American Journal of Clinical Nutrition, ISSN 0002-9165, E-ISSN 1938-3207, Vol. 92, no 3, p. 532-538Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Recent data revealed differences in human absorption kinetics and metabolism between food folates and folic acid supplements and fortificant.

    OBJECTIVE: The objective was to determine folate bioavailability after ingestion of breads or a breakfast meal fortified with either 5-CH(3)-H(4) folate or folic acid by using a stable-isotope area under the curve (AUC) and ileostomy model.

    DESIGN: In a randomized crossover trial, healthy ileostomists (n = 8) ingested single doses of whole-meal bread that contained ap 450 nmol (200 micro g) of either (6S)-[(13)C(5)]5-CH(3)-H(4) folate or [(13)C(5)]folic acid or a breakfast meal that contained ap 450 nmol (200 micro g) [(13)C(5)]folic acid. We collected blood from the subjects during 12 h postdose for assessment of plasma kinetics. Nonabsorbed folate was assessed from labeled folate contents in stomal effluent 12 and 24 h postdose.

    RESULTS: The median (range) plasma AUC(0 rarr 12) (AUC from 0 to 12 h after ingested dose) of 66 nmol sdot h/L (34-84 nmol sdot h/L) after ingestion of bread that contained (6S)-[(13)C(5)]5-CH(3)-H(4) folate was significantly greater (P lt 0.001) than that after ingestion of [(13)C(5)]folic acid in fortified bread [28 nmol sdot h/L (15-38 nmol sdot h/L)] and a fortified breakfast meal [26 nmol sdot h/L (15-60 nmol sdot h/L)]. Both labeled doses resulted in increases of plasma [(13)C(5)]5-CH(3)-H(4) folate. However, the kinetic variables C(max) (maximum plasma concentration) and T(max) [time (min) of maximum plasma concentration] varied after ingestion of the different folate forms. The stomal folate content was lt 10% of the ingested dose and did not vary significantly after ingestion of test foods that contained (6S)-[(13)C(5)]5-CH(3)-H(4) folate [median (range): 13 nmol (10-31 nmol)] or [(13)C(5)]folic acid [median (range): 25 nmol (8-42 nmol)] (P = 0.33).

    CONCLUSIONS: Our data confirm differences in plasma absorption kinetics for reduced folates and synthetic folic acid administered with the test foods. Stomal folate contents indicated almost complete bioavailability of labeled folate from the breads or breakfast meal.

  • 65.
    Öhrvik, Veronica E
    et al.
    Sveriges lantbruksuniversitet, Uppsala.
    Olsson, Johan C
    Sveriges lantbruksuniversitet, Uppsala.
    Sundberg, Birgitta E
    Sveriges lantbruksuniversitet, Uppsala.
    Witthöft, Cornelia M.
    Sveriges lantbruksuniversitet, Uppsala.
    Effect of 2 pieces of nutritional advice on folate status in Swedish women: a randomized controlled trial.2009In: American Journal of Clinical Nutrition, ISSN 0002-9165, E-ISSN 1938-3207, Vol. 89, no 4, p. 1053-1058Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Ten years after the introduction of mandatory folic acid fortification in the United States, Canada, and Costa Rica, the issue is still under debate in several countries, and Sweden recently decided against mandatory fortification.

    OBJECTIVE: The objective was to determine the folate status of women after an intervention involving 2 Swedish dietary recommendations: a food recommendation (bread) and a complete meal recommendation (breakfast).

    DESIGN: Fifty-one free-living women with normal folate status participated in a 12-wk controlled intervention trial. Subjects were randomly assigned to one of the following interventions: apple juice (control group; n = 17), a breakfast providing 125 microg folate (breakfast group; n = 17), or 5 slices of whole-meal bread to be eaten over the course of the day, which provided 70 microg folate (bread group; n = 17). Folate status was assessed on the basis of concentrations of erythrocyte folate, serum folate, and plasma total homocysteine (tHcy) at baseline and at weeks 8 and 12 of the trial.

    RESULTS: In the breakfast group, initial median concentrations of erythrocyte folate (805 nmol/L) increased by 172 nmol/L (95% CI: 24, 293; P = 0.02) relative to the control. The relative increase in initial serum folate (2 nmol/L, 95% CI: 0, 5; P = 0.06) was nonsignificant. The initial tHcy concentration (8.7 micromol/L) decreased by 2.3 micromol/L (95% CI: -1, -3.4; P < 0.01). In the bread group, the initial tHcy concentration (9.1 micromol/L) decreased nonsignificantly by 1.4 micromol/L (95% CI: 0, -2.8; P = 0.08) relative to the control group, whereas other outcomes were stable.

    CONCLUSIONS: The folate status of the subjects improved after regular consumption of the breakfast meal. The additional folate intake from the bread maintained the folate status but was not sufficient to improve it.

  • 66.
    Öhrvik, Veronica E
    et al.
    National Food Administration, Uppsala.
    Witthöft, Cornelia M.
    Sveriges lantbruksuniversitet, Uppsala.
    Human folate bioavailability2011In: Nutrients, ISSN 2072-6643, E-ISSN 2072-6643, Vol. 3, no 4, p. 475-490Article in journal (Refereed)
    Abstract [en]

    The vitamin folate is recognized as beneficial health-wise in the prevention of neural tube defects, anemia, cardiovascular diseases, poor cognitive performance, and some forms of cancer. However, suboptimal dietary folate intake has been reported in a number of countries. Several national health authorities have therefore introduced mandatory food fortification with synthetic folic acid, which is considered a convenient fortificant, being cost-efficient in production, more stable than natural food folate, and superior in terms of bioavailability and bioefficacy. Other countries have decided against fortification due to the ambiguous role of synthetic folic acid regarding promotion of subclinical cancers and other adverse health effects. This paper reviews recent studies on folate bioavailability after intervention with folate from food. Our conclusions were that limited folate bioavailability data are available for vegetables, fruits, cereal products, and fortified foods, and that it is difficult to evaluate the bioavailability of food folate or whether intervention with food folate improves folate status. We recommend revising the classical approach of using folic acid as a reference dose for estimating the plasma kinetics and relative bioavailability of food folate.

  • 67.
    Öhrvik, Veronica
    et al.
    Swedish University of Agricultural Sciences.
    Witthöft, Cornelia M.
    Swedish University of Agricultural Sciences.
    Can foods naturally high in folate improve folate status?: Results from an intervention trial2007In: Annals of Nutrition and Metabolism, ISSN 0250-6807, E-ISSN 1421-9697, Vol. 51, no suppl 1, p. 204-204, article id P306Article in journal (Refereed)
  • 68.
    Öhrvik, Veronica
    et al.
    Swedish University of Agricultural Sciences.
    Witthöft, Cornelia M.
    Swedish University of Agricultural Sciences.
    Orange juice is a good folate source in respect to folate content and stability during storage and simulated digestion2008In: European Journal of Nutrition, ISSN 1436-6207, E-ISSN 1436-6215, Vol. 47, no 2, p. 92-98Article in journal (Refereed)
    Abstract [en]

    Background

    Estimated average folate intake in Sweden is less than 55% of the recommended daily intake (RDI) for women of childbearing age (Becker and Pearson in Riksmaten 1997–1998 Kostvanor och näringsintag i Sverige. National Food Administration, Uppsala, pp 34, 44, 121, 2002). Because a good folate status reduces the risk of neural tube defects, mandatory folic acid fortification is discussed in some European countries. This however, could lead to exposure to unintentionally high amounts of folic acid for some population groups, therefore targeted folic acid fortification could be an alternative.

    Aims

    To (1) determine natural folate content in three popular brands of orange juice sold in Sweden, (2) determine stability of natural folate and folic acid fortificant during shelf life in a folic acid/iron fortified orange juice, (3) determine folate stability in four juices during simulated household consumption for one week and (4) determine the in vitro bioaccessibility of natural folate in one brand of orange juice using the TNO gastroIntestinal Model (TIM).

    Methods

    Natural folate content in juices was determined using RP-HPLC-FL. To determine folic acid content and confirm RP-HPLC-FL values LCMS was used. Stability during shelf life was determined in unopened bottles of a folic acid/iron fortified juice and for one week in four popular juices under household consumption conditions with reopening of bottles daily. For an in vitro folate bioaccessibility experiment in orange juice the TNO TIM Model was used.

    Results

    5-CH3-H4folate was the dominant natural folate form in the juices with contents ranging from 16–30 µg/100 g. Shelf life losses of folic acid fortificant were 1–4%. During one week simulated household consumption 5-CH3-H4folate content decreased by up to 7% (n.s). Bioaccessibility of natural folate in orange juice was almost 100%. Most folate was released for absorption in jejunum between 60–120 min after trial start.

    Conclusion

    Orange juice may be considered a good source of natural folate in respect to content and stability during storage and simulated digestion. Moreover, added folic acid fortificant in a folic acid/iron fortified orange juice was stable during shelf life.

  • 69. Öhrvik, Veronica
    et al.
    Öhrvik, Helena
    Tallkvist, Jonas
    Witthöft, Cornelia M.
    Sveriges lantbruksuniversitet, Uppsala.
    Folates in bread: retention during bread-making and in vitro bioaccessibility2010In: European Journal of Nutrition, ISSN 1436-6207, E-ISSN 1436-6215, Vol. 49, no 6, p. 365-372Article in journal (Refereed)
    Abstract [en]

    BACKGROUND: Bread is an important folate source in several countries. However, bread-making was reported to cause losses of endogenous bread folates (approximately 40%) as well as added synthetic folic acid (approximately 30%). Furthermore, the bread matrix is suggested to inhibit absorption of folates.

    PURPOSE: To (1) estimate retention of both, endogenous folates and synthetic fortificants, during bread-making, (2) assess in vitro folate bioaccessibility from breads and a breakfast meal and (3) assess in vitro folate uptake.

    METHODS: Retention of folate forms was assessed by preparing fortified (folic acid and [6S]-5-CH(3)-H(4)folate) wholemeal breads and collect samples from dough, proofed dough and the bread. In vitro folate bioaccessibility was assessed using the TNO gastrointestinal model TIM. In vitro folate uptake was assessed using a novel Caco-2 cell/stable isotope model. Folate content in samples was measured using LCMS.

    RESULTS: Bread-making resulted in losses of 41% for endogenous folates and up to 25 and 65% for folic acid and [6S]-5-CH(3)-H(4)folate fortificant, respectively. 75% of endogenous bread folates and 94% of breakfast folates were bioaccessible as assessed by TIM. From [6S]-5-CH(3)-H(4)folate-fortified bread, relative folate uptake into Caco-2 cells was 71 +/- 11% (P < 0.05) when compared with a standard solution.

    CONCLUSION: Retention of folic acid fortificant during bread-making was substantially higher compared to retention of [6S]-5-CH(3)-H(4)folate fortificant. Data from the TIM and Caco-2 cell trials suggest an inhibiting effect of the tested bread matrices on in vitro bioaccessibility of folates, whereas folate bioaccessibility from a breakfast meal is almost complete.

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