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1.
A coupled in vitro digestion/Caco-2 model was employed to assess iron bioavailability from wheat Aegilops derivatives selected for high iron and protein contents. The iron content in wheat genotypes used in this study correlated to a great extent with both protein (r = 0.80) and phytate (r = 0.68) contents. The iron bioavailability was based on Caco-2 cell ferritin formation from cooked digests of these derivatives (relative to WL711 control) and correlated positively with dialyzable iron (r = 0.63) and total iron content (r = 0.38) but not with the phytate content. The apparently decreased phytate/iron molar ratios, however, correlated negatively (r = -0.42) with the iron bioavailability, justifying the utilization of these parameters in biofortification programs. Iron bioavailability in the derivatives increased up to 1.5-fold, corresponding to a 1.5-2.2-fold increase observed in iron content over control. These data suggest that biofortification for iron proportionately leading to higher iron bioavailability will be the most feasible and cost-effective approach to combat micronutrient deficiency.  相似文献   

2.
An in vitro digestion/Caco-2 model was used to compare iron bioavailability from 15 selected Fe-dense and normal genotypes of unpolished rice from the International Rice Research Institute. Iron uptake was determined using Caco-2 cell ferritin formation in response to exposure to a digest of the cooked rice. Iron bioavailabilities from all rice genotypes were ranked as a percent relative to a control variety (Nishiki). Iron concentration in the rice samples ranged from 14 to 39 microg/g. No correlation was observed between Fe uptake and grain-Fe concentration. Furthermore, phytic acid levels were not correlated with Fe bioavailability. Genotypes with low Fe bioavailability (Tong Lan Mo Mi, Zuchein, Heibao, and Xua Bue Nuo) were noticeably more brown to purple in color. The results suggest that certain unknown compounds related to rice grain color may be a major factor limiting Fe bioavailability from unpolished rice.  相似文献   

3.
Iron deficiency is the most common nutritional disorder worldwide. Iron fortification of foods is considered to be the most cost-effective long-term approach to reduce iron deficiency. However, for fortified foods to be effective in reducing iron deficiency, the added iron must be sufficiently bioavailable. In this study, fortification of whole-grain wheat flour with different sources of iron was evaluated in vitro by measuring the amount of dialyzable iron after simulated gastrointestinal digestion of flour baked into chapatis and subsequent intestinal absorption of the released iron using Caco-2 cell layers. The dialyzability of iron from iron-fortified wheat flour was extremely low. Additions of 50 mg/kg iron to the flour in the form of ferrous sulfate, Ferrochel amino acid chelate, ferric amino acid chelate taste free (TF), Lipofer, ferrous lactate, ferrous fumarate, ferric pyrophosphate, carbonyl iron, or electrolytic iron did not significantly increase the amount of in vitro dialyzable iron after simulated gastrointestinal digestion. In contrast, fortification of flour with SunActive Fe or NaFeEDTA resulted in a significant increase in the amount of in vitro dialyzable iron. Relative to iron from ferrous sulfate, iron from SunActive Fe and NaFeEDTA appeared to be 2 and 7 times more available in the in vitro assay, respectively. Caco-2 cell iron absorption from digested chapatis fortified with NaFeEDTA, but not from those fortified with SunActive Fe, was significantly higher than from digested chapatis fortified with ferrous sulfate. On the basis of these results it appears that fortification with NaFeEDTA may result in whole-grain wheat flour that effectively improves the iron status.  相似文献   

4.
Milk proteins, during digestion, produce a range of biologically active peptides. Among those are peptides that may enhance iron absorption. The objective of this project was to investigate the effect of isolated milk peptides on iron uptake. Cow's milk, 0% fat, was subjected to a modified in vitro digestion process. The milk digest was further fractionated by gel filtration. All eluted fractions as well as beta-casein synthetic peptides (a tripeptide and a hexapeptide) were subsequently tested for effects on iron uptake with Caco-2 cell monolayers. Fractions of milk digests obtained through Sephadex G-25 gel filtration had a significant enhancing effect on iron uptake in Caco-2 cells compared to nonfractionated milk digests. Two fractions (P = 0) and the hexapeptide (P < 0.0001) enhanced iron uptake by up to 3-fold, whereas others and the tripeptide had no effect. These results suggest that selected peptides produced during the in vitro digestion of milk may enhance iron absorption; however, it remains to be demonstrated whether this effect may be nutritionally significant.  相似文献   

5.
Adequate bioavailable Fe intake is essential for optimal growth and intellectual development of infants and children. Fruit juices are nutritious and popular drinks for infants and children and are known to contain Fe uptake inhibitors (e.g., polyphenolic compounds) and a dominant promoter, ascorbic acid. Ascorbic acid is naturally present in fruit juices and is added during processing to almost all juices found in supermarkets. With these facts taken into account, an in vitro digestion/Caco-2 cell culture model was developed to compare the effects of apple, pear, white grape, red grape, prune, grapefruir, and orange juices on iron bioavailability. In two series of experiments, juices from a local supermarket were combined with FeCl(3) or commercial infant cereal fortified with elemental iron and subject to simulated gastric and intestinal digestion. Caco-2 cell ferritin formation in response to exposure to the digests served as the measure of Fe uptake. The pear, apple, grapefruit, orange, and white grape juice significantly increased Fe bioavailability from FeCl(3). For the infant cereal studies, the apple, orange, pear, and white grape juices increased the Fe bioavailability of the infant cereal. In contrast, the red grape juice and prune juice had profound inhibitory effects on iron bioavailability. These inhibitory effects were likely due to high levels of polyphenolic compounds that bind and thereby prevent absorption of soluble Fe. These inhibitory compounds appeared to counteract the promotional effects of ascorbic acid as they were in considerable molar excess relative to ascorbic acid and Fe in the digest. From a nutritional standpoint, the results suggest that individuals in need of optimal Fe absorption should avoid red grape and prune juice or at least vary the types of juices consumed. Alternatively, individuals seeking to limit Fe uptake (e.g., hemochromatitics and astronauts) may be able to utilize red grape or prune juice as effective inhibitors of Fe uptake. Consumers should be aware that the compounds that inhibit Fe availability are also linked to anticancer benefits; thus, a dietary balance of the above juices may be optimal.  相似文献   

6.
The bioavailability of iron from fortified fruit beverages was estimated by an in vitro system including enzymatic digestion, iron uptake by Caco-2 cells, and ferritin formation determined via an enzyme immunoassay (ELISA). Thus, the aim of the present study was to assess iron bioavailability as influenced by the presence of known dietary promoter and inhibitory factors in fortified fruit beverages containing iron and/or zinc and/or skimmed milk. No negative effect ( p > 0.05) derived from micronutrient interaction can be ascribed to zinc supplementation on iron availability. Besides, the presence of caseinophosphopeptides derived from casein hydrolysis during digestion may confer enhancing effects on iron absorption in samples with milk added with respect to nonadded samples ( p < 0.05). Therefore, from a nutritional point of view, individuals in need of optimal iron absorption may choose dairy samples to ensure optimal iron bioavailability.  相似文献   

7.
The objective of this study was to determine if a combination of commercially available mucin and an 8 microm microporous membrane insert can be used to replace the 15 kDa molecular weight cutoff (MWCO) dialysis membrane used in an established in vitro digestion/Caco-2 cell culture system. Although the current model with the 15 kDa membrane correlates well with human studies, use of mucin may improve the system as the mucus layer is suspected to play a physiological role in Fe absorption. Use of mucin may also enable more complete assessment of iron bioavailability from large molecular weight forms of Fe such as heme and ferritin Fe. A range of foods or Fe (i.e., FeCl(3) +/- ascorbic acid, cooked beef, red bean, white bean, soybean, horse spleen ferritin and plant-type ferritin) were subjected to in vitro digestion. In the presence of mucin, significantly more Fe was taken up from the heme Fe (86%) and ferritin (91%) samples and significantly less Fe was taken up from the white bean samples ( approximately 70%) relative to the 15 kDa membrane. The results indicated that the forms of iron interact with mucin. The mucus layer has a significant effect on Fe uptake. Further refinement and characterization of the mucin method is needed before it can be deemed to be a suitable replacement for the dialysis membrane.  相似文献   

8.
Iron (Fe) deficiency is a difficult nutrient problem particularly in crop plants grown on calcareous soils. Recently, phytosiderophore (PS) release has been linked to the ability of graminaceous species and genotypes to withstand Fe-deficiency chlorosis. So enhancing PS release is a critical step to improve iron efficiency of plants grown on iron stressed soils. The effects of alien cytoplasm on PS release in spring wheat were studied by analyzing PS release from twenty wheat genotypes, including two spring wheat 881 and 352-35, and their 18 alloplasmic lines with the participation of cytoplasms from the Aegilops and Triticum species. Different genotypes were grown in iron sufficient and deficient nutrient solution under controlled environmental conditions. PS release rates were determined at two or three days intervals after onset of iron deficiency symptoms by the measurement of iron mobilizing capacity of root exudates from freshly precipitated FeIII hydroxide. High amounts of phytosiderophores were released from roots of all wheat genotypes without iron supplied, and the amount progressively increased with the development of iron deficiency chlorosis. The results revealed that (1) the release rate of phytosiderophores from roots of common wheat could be considerably influenced by alien cytoplasms. Some alien cytoplasms exerted positive effects, some ones did negative effects, and the other ones had no significant effects. (2) the same alien cytoplasm could affect similarly or oppositely the phytosiderophores release from different wheat. (3) some alien cytoplasms, such as Chinese Spring, Ae. speltoides Tausch and Ae. cylindrica Host showed promising and potential in improving the rate of phytosiderophore release in common wheat. These cytoplasms which showed the desired effect should be given priority in interspecific and intergeneric hybridization to develop and reconstruct the needed wheat cultivars.  相似文献   

9.
Iron chelates, namely, ferrous bisglycinate and ferric EDTA, are promising alternatives to iron salts for food fortification. The objectives of this study were to compare iron uptake from radiolabeled ferrous sulfate, ferrous ascorbate, ferrous bisglycinate, ferric chloride, ferric citrate, and ferric EDTA by Caco-2 cells with different iron status and in the presence of divalent metal cations. Iron-loaded Caco-2 cells, with reduced DMT-1 and elevated HFE mRNA levels, down-regulated uptake from ferrous ascorbate and bisglycinate but not from ferric compounds. Nevertheless, iron uptake from all compounds was markedly inhibited in the presence of 100-fold molar excess of Co2+ and Mn2+ cations, with ferrous compounds showing a greater percent reduction. Our results suggest that ferrous iron is the predominant form of iron taken up by intestinal epithelial cells and the DMT-1 pathway is the major pathway for uptake. Iron uptake from chelates appears to follow the same pathway as uptake from salts.  相似文献   

10.
Our aim was to estimate the bioavailability of calcium, iron, and zinc from infant formulas using a model that includes in vitro digestion and a Caco-2 cell culture to estimate the uptake. The cell culture conditions were selected, and uptake assays were carried out first with calcium, iron, and zinc standard solutions, and then with the soluble fraction of enzymatic digests of an adapted milk-based and a soy-based infant formula. It was not possible to measure the uptake of calcium, iron, and zinc from standard solutions added to the cell cultures in amounts similar to those present in infant formula digests with our method. The fact that it was, however, possible in the case of enzymatic digests suggests the presence of components in the digests that enhance mineral uptake. When mineral uptakes were expressed as percentages of the mineral present, statistically significant differences were found in the case of calcium between the uptake from the milk- and the soy-based formulas. For iron and zinc no such differences were observed.  相似文献   

11.
The iron dialyzability and uptake in relation to transit time through the stomach and small intestine was investigated using a dynamic in vitro gastrointestinal model in combination with Caco-2 cells. Three test meals were evaluated, consisting of lactic fermented vegetables with white (I) or whole meal bread (II) and of sourdough-fermented rye bread (III). Three transit times were tested (fast, medium, and slow transport). Iron dialyzability and absorption differed significantly between medium and slow transit time for meal I and between fast and medium transit time for meal III. For meal II, high in phytate, the iron dialyzability and absorption were low irrespective of transit time. The meals could be ranked with respect to iron dialyzability and uptake in the order I > III > II. Although the in vitro models used have limitations compared to in vivo experiments, the results suggest that an increased transit time may improve iron availability.  相似文献   

12.
A pool of selected lactic acid bacteria was used to ferment durum wheat semolina under liquid conditions. After fermentation, the dough was freeze-dried, mixed with buckwheat flour at a ratio of 3:7, and used to produce the "fusilli" type Italian pasta. Pasta without prefermentation was used as the control. Ingredients and pastas were characterized for compositional analysis. As shown by two-dimensional electrophoresis, 92 of the 130 durum wheat gliadin spots were hydrolyzed almost totally during fermentation by lactic acid bacteria. Mass spectrometry matrix-assisted laser desorption/ionization time-of-flight and reversed phase high-performance liquid chromatography analyses confirmed the hydrolysis of gliadins. As shown by immunological analysis by R5-Western blot, the concentration of gluten decreased from 6280 ppm in the control pasta to 1045 ppm in the pasta fermented with lactic acid bacteria. Gliadins were extracted from fermented and nonfermented durum wheat dough semolina and used to produce a peptic-tryptic (PT) digest for in vitro agglutination tests on cells of human origin. The whole PT digests did not cause agglutination. Affinity chromatography on Sepharose-6-B mannan column separated the PT digests in three fractions. Fraction C showed agglutination activity. The minimal agglutinating activity of fraction C from the PT digest of fermented durum wheat semolina was ca. 80 times higher than that of durum wheat semolina. Pasta was subjected to sensory analysis: The scores for stickiness and firmness were slightly lower than those found for the pasta control. Odor and flavor did not differ between the two types of pasta. These results showed that a pasta biotechnology that uses a prefermentation of durum wheat semolina by selected lactic acid bacteria and tolerated buckwheat flour could be considered as a novel tool to potentially decrease gluten intolerance and the risk of gluten contamination in gluten-free products.  相似文献   

13.
微生物在植物铁营养中的潜在作用   总被引:4,自引:1,他引:4  
根据近十多年来相关研究成果讨论了土壤微生物在植物根系吸收铁中可能的作用机理。这种机理可能包括缺铁植物根系分泌小分子有机化合物,如酚类和黄素类等化合物,这些化合物作为抑菌剂和(或)作为微生物生长的碳源物质来影响根际(Rhizosphere)微生物的群落结构,并在植物根际诱导形成特异性微生物种群,此类特异性微生物转而通过分泌高铁载体(Siderophore),增加土壤中铁的生物有效性,从而提高了根系对铁的吸收。此外,与植物根系共生的一些微生物也会改善植物的铁营养,这种作用可能包括:根瘤菌(Rhizobium)的结瘤作用,增强植物耐缺铁的生理响应;根系感染的菌根真菌通过增加植物根系的养分吸收面积和分泌对铁具有螯合作用的物质来改善植物的铁营养。本文在讨论这种可能的微生物作用机制的基础上,指出今后的研究方向和有待解决的问题。  相似文献   

14.
The reduced iron powder has considerable potential for use as an iron fortificant because it does not change organoleptically during storage or food preparation for cereal flour, and its bioavailability is scarcely influenced by iron absorption inhibitors in foods. The objective of this article is to study the effects of ascorbic acid, phytic acid, and pH on iron uptake from reduced iron powder (43 microm) and FeSO 4, and to compare iron bioavailability of reduced iron powders among four selected granularity levels. The cell ferritin formation is used as a marker of iron uptake. Obviously, iron uptake of reduced iron powder is increased with decreasing of powder granularity and is much lower than FeSO 4 when the size is above 43 microm, but significantly higher at 40-60 nm. In the presence of ascorbic acid or phytic acid, Caco-2 cell iron absorption from reduced iron powder (43 microm) is significantly higher than that from FeSO 4. And iron uptake of Caco-2 cells is decreased with increasing of pH from 5.5 to 7.5. Moreover, the decrease trend is more obvious for reduced iron powder than for FeSO 4. Our results indicated that iron bioavailability of reduced iron powder by intestinal enterocytes is similar to that of iron salts, and reduced iron powder is more excellent than FeSO 4 as food fortificant, especially at ultramicroscopic granularity.  相似文献   

15.
The objective of this study was to document the effects of phytic acid, tannic acid, and zinc on iron uptake in an in vitro digestion/Caco-2 cell culture model. The effects of phytic acid and tannic acid on iron uptake were measured at increasing molar ratios of FeCl3 to phytic acid or tannic acid. Maximal inhibition of iron uptake by phytic acid occurred at a 1:10 ratio of Fe to phytic acid. Dialyzable Fe decreased with a low Fe to phytic acid ratio but increased with Fe:phytic acid ratios greater than 1:3 indicating that more iron was soluble at higher phytic acid levels but less available. As in human studies, heme iron was less inhibited by phytic acid than nonheme iron. Tannic acid was a more potent inhibitor of nonheme iron uptake, as maximal inhibition (97.5%) of iron uptake occurred at a ratio of 1:1 or less. The addition of ZnCl2 to the digest at ratios of 1:0.5 and 1:1 decreased iron uptake by 57 and 80%, respectively. Overall, the results agree qualitatively with studies in humans and demonstrate the relative effects of these compounds on iron uptake in this model system. This study provides key information for determining iron availability under more complex meal conditions.  相似文献   

16.
Abstract

The Colorado State University biosolids research program has routinely used concentrated nitric acid for digesting plant tissue for subsequent inductively coupled plasma‐atomic emission spectrometry analyses. The original method outlined by Havlin and Soltanpour calls for samples to be heated on an aluminum block at 125°C until the liquid volume is reduced to 2–3 mL. However, some plant species require >17 hours to reduce to 3 mL, while other plant species boil out of the digestion tubes at 125°C; some do both. The objective of this research was to determine if a timed digestion period could yield similar results to the original volume reduction method for plant species routinely analyzed in our laboratory. We performed digests on winter wheat grain and straw (Triticum aestivum L., ‘TAM 107'), fringed sage (Artemisia frigida Willd.), and an NIST wheat flour standard (NIST Standard Reference Material 1567a). We predigested 1.00 g plant material in 10 mL of concentrated nitric acid (69% by weight) at room temperature for 24, 48, or 72 hours, and we predigested plants for 24 hours followed by sample placement on an aluminum block digester. All samples were vortexed at 6, 24, 48, or 72 hours, accordingly. Block samples were initially digested at 80°C until fuming ceased, followed by an increase in temperature to 120°C and digested for 2, 4, 6, or 8 hours, or volume reduction to 3 mL. We used four replications and two blanks for all digests. We analyzed all samples using ICP‐AES and compared all results to the original digestion method. Overall comparison of all plants showed the block digestion to be superior to all predigestion periods. Winter wheat grain digested the quickest on the block, with all digests being complete within ~4 hours. The 4 hour block digestion compared well with the normal digest for our wheat grain. The 8 hour block digestion period for the other plant species all compared well with the normal digest. We suggest the following procedural modification: predigest all samples for 24 hours, with subsequent vortexing at 6 and 24 hours; place samples on an aluminum block at 80°C until fuming ceases; increase the temperature to 120°C and digest for 8 hours or until 3 mL remain, whichever occurs first.  相似文献   

17.
This study continues previous research to confirm that glycosaminoglycans (GAGs) exert a positive effect on promoting iron uptake by Caco-2 cells. Cooked haddock was digested with papain, and GAGs were further purified on the basis of their sulfur content. Reverse phase chromatography (RP-HPLC) and digestion with chondroitinase ABC (Chase) (50 mU/mg) were used to approach the identification of the GAGs. FeCl 3 was mixed with the purified GAGs, and Fe uptake was measured by ferritin formation using an in vitro digestion/Caco-2 cell model. The identificative analyses suggest that chondroitin/dermatan sulfate-related structures promote Fe uptake by Caco-2 cells; however, this effect was lower (40%) than that observed with whole fish muscle. Chase eliminated the positive effect on Fe uptake. These results indicate that specific GAGs may contribute to the enhancing effect of meat on Fe absorption. Further in vivo studies addressing these aspects of the meat factor are needed.  相似文献   

18.
Four different colored beans (white, red, pinto, and black beans) were investigated for factors affecting iron bioavailability using an in vitro digestion/human Caco-2 cell model. Iron bioavailability from whole beans, dehulled beans, and their hulls was determined. The results show that white beans contained higher levels of bioavailable iron compared to red, pinto, and black beans. These differences in bioavailable iron were not due to bean-iron and bean-phytate concentrations. Flavonoids in the colored bean hulls were found to be contributing to the low bioavailability of iron in the non-white colored beans. White bean hulls contained no detectable flavonoids but did contain an unknown factor that may promote iron bioavailability. The flavonoids, kaempferol and astragalin (kaempferol-3-O-glucoside), were identified in red and pinto bean hulls via HPLC and MS. Some unidentified anthocyanins were also detected in the black bean hulls but not in the other colored bean hulls. Kaempferol, but not astragalin, was shown to inhibit iron bioavailability. Treating in vitro bean digests with 40, 100, 200, 300, 400, 500, and 1000 microM kaempferol significantly inhibited iron bioavailability (e.g., 15.5% at 40 microM and 62.8% at 1000 microM) in a concentration-dependent fashion. Thus, seed coat kaempferol was identified as a potent inhibitory factor affecting iron bioavailability in the red and pinto beans studied. Results comparing the inhibitory effects of kaempferol, quercitrin, and astragalin on iron bioavailability suggest that the 3',4'-dihydroxy group on the B-ring in flavonoids contributes to the lower iron bioavailability.  相似文献   

19.
植物应答缺铁胁迫的分子生理机制及其调控   总被引:3,自引:0,他引:3  
铁是植物生长发育中所必需的微量营养元素。虽然土壤中铁的丰度很高,但其生物有效性非常低,特别是在碱性石灰性土壤上,高pH和高重碳酸盐含量严重降低了土壤中铁的有效性。因此如何有效地提高植物对铁的利用效率及增强植物对缺铁胁迫的响应已成为目前该领域的研究热点。本文重点阐述了植物两种不同的铁吸收机制,以及对缺铁胁迫的应答反应;对目前所发现的植物中调控缺铁胁迫的相关基因进行了全面的综述,包括新发现的吞噬机理中所涉及的NRAMP基因;同时也介绍了感应铁缺乏的众多相关信号,包括植物激素、气体信号分子及microRNAs等;此外,还提出利用铁吸收相关基因的转导、控制铁吸收相关因子以及各种农艺措施的实施来提高植物铁的生物有效性从而有效缓解缺铁胁迫。最后对未来有关植物吞噬机制、铁缺乏感应信号及改善植物铁营养新途径等研究方向作了初步展望。  相似文献   

20.
OBJECTIVE: The objective of this study was to identify the determinants of anaemia in Lebanese women of childbearing age attending health centres in Lebanon. DESIGN: Cross-sectional study carried out between May and December 2003. Anthropometric measurements as well as sociodemographic, health and dietary intake data were collected using a questionnaire. Haemoglobin (Hb), plasma ferritin, plasma folate and vitamin B12 were assessed using standard laboratory methods. SETTING: Governmental health centres in Lebanon. SUBJECTS: Four hundred and seventy non-pregnant Lebanese women aged 15-45 years. RESULTS: Anaemia (Hb <12 g dl(-1)) and iron deficiency (ferritin <15 microg l(-1)) were prevalent in 16.0 and 27.2% of the study sample, respectively. Of the total sample, 7.7% had iron-deficiency anaemia. The percentage of women with either Hb or ferritin deficiency or both was 35.6%. Plasma folate and vitamin B12 deficiency was reported in 25.1 and 39.4%, respectively, and 12.6% of the women had both folate and vitamin B12 deficiencies. Of the anaemic group, 48.0% of the women had iron deficiency. The intake of iron was lower in iron-deficient than in non-deficient women and a positive relationship was shown between folate intake and its corresponding serum levels. Regression analysis showed that ferritin, plasma folate and family history of anaemia were significant determinants of the anaemia in the sample of women. CONCLUSIONS: Anaemia not related to iron deficiency was partly explained by plasma folate deficiency. Measures to control folate and iron deficiency should be considered.  相似文献   

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