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Content and In Vitro Accessibility of Provitamin. A Carotenoids in Some Tanzanian Vegetables and Fruits Effects of Traditional Processing and Preparation, and Influence on Vitamin A Status
No full textVitamin A deficiency is among the major nutritional problems in Tanzania as in many developing countries. It mainly affects children and pregnant and lactating women. The basic cause of this problem is related to the diet, which contains little preformed vitamin A and plant foods with a low content and bioavailability of provitamin A carotenoids. This thesis reports studies conducted to evaluate the content and bioavailability of provitamin A carotenoids in selected fruits and vegetables from Tanzania and to elucidate the effects of different processing and preparation methods. The vitamin A and provitamin A carotenoid status in pregnant women was assessed in relation to the dietary intake pattern of provitamin A carotenoids and after supplementation with cooking oil. Results showed that leafy vegetables contain high but variable amounts of all-trans-β-carotene (399-914 µg/g dry weight) and minor amounts of α-carotene, 9-cis- and 13-cis-β-carotene. Fruits contain variable amounts of all-trans-β-carotene (191-5502 µg/100g fresh weight) and some fruits have minor amounts of β-cryptoxanthin and lycopene. Open sun dried leafy vegetables had significantly (
Content and In Vitro Accessibility of Provitamin. A Carotenoids in Some Tanzanian Vegetables and Fruits Effects of Traditional Processing and Preparation, and Influence on Vitamin A Status
No full textVitamin A deficiency is among the major nutritional problems in Tanzania as in many developing countries. It mainly affects children and pregnant and lactating women. The basic cause of this problem is related to the diet, which contains little preformed vitamin A and plant foods with a low content and bioavailability of provitamin A carotenoids. This thesis reports studies conducted to evaluate the content and bioavailability of provitamin A carotenoids in selected fruits and vegetables from Tanzania and to elucidate the effects of different processing and preparation methods. The vitamin A and provitamin A carotenoid status in pregnant women was assessed in relation to the dietary intake pattern of provitamin A carotenoids and after supplementation with cooking oil. <p />Results showed that leafy vegetables contain high but variable amounts of all-<I>trans</I>-β-carotene (399-914 µg/g dry weight) and minor amounts of α-carotene, 9-<I>cis</I>- and 13-<I>cis</I>-β-carotene. Fruits contain variable amounts of all-<I>trans</I>-β-carotene (191-5502 µg/100g fresh weight) and some fruits have minor amounts of β-cryptoxanthin and lycopene. Open sun dried leafy vegetables had significantly (p<0.05) lower amounts of all-<I>trans</I>-β-carotene (53%) than the fresh vegetables, whereas vegetables dried in solar cabinets showed losses of only about 23%. Cooking caused variable losses (6-51%) in all-<I>trans</I>-β-carotene content of the vegetables. The bioaccessibility (amount available for absorption) of the provitamin A carotenoids was estimated with an <I>in vitro </I>digestion method that simulates conditions in the human gastrointestinal tract. The <I>in vitro</I> accessibility of all-<I>trans</I>-β-carotene was low (4-15%) in vegetables cooked without added oil. However, higher (2 to 5-fold) <I>in vitro</I> accessibility of all-<I>trans</I>-β-carotene was obtained in vegetables cooked with added cooking oil. An addition of red palm oil provided significant amounts of accessible provitamin A carotenoids due to its high content of α- and β-carotene. Conversion of the amount of accessible provitamin A carotenoids into retinol equivalents according to FAO/WHO recommendations revealed that a median portion of a vegetable relish as consumed by children provided 88 to 477% of the recommended safe daily intake level (RSDIL) of vitamin A. Portions cooked without oil provided only between 23 and 46%. The <I>in vitro</I> accessible all-<I>trans</I>-β-carotene in fruits varied between 7% and 100%, and an edible portion of fruit (150g) would provide between 27 and 216 % of the RSDIL of vitamin A to children. <p />Consumption of preformed vitamin A by pregnant women was very low and higher plasma retinol levels were correlated (p=0.03) with higher intakes of vegetables with oil. Supplementation with red palm oil increased α- and β-carotene concentrations significantly (p<0.001) in both plasma and breast milk. The breastmilk retinol concentration tended to decrease from 1 to 3 months postpartum in the control group but was maintained in the groups given supplements of either red palm oil or sunflower oil
Effect of traditional open sun-drying and solar cabinet drying on carotene content and vitamin A activity of green leafy vegetables
No full textEffect of traditional open sun-drying and solar cabinet drying on carotene content and vitamin A activity of green leafy vegetables
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Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
In vitro accessibility and intake of Β-carotene from cooked freen leafy vegetables and their estimated contribution to vitamin A requirements
No full textVariations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
In vitro accessibility and intake of Β-carotene from cooked freen leafy vegetables and their estimated contribution to vitamin A requirements
No full textAppropriate Similarity Measures for Author Cocitation Analysis
Get PDFWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
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