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Changes in iron, zinc and chelating agents during traditional African processing of maize: Effect of iron contamination on bioaccessibility

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Changes in iron, zinc and chelating agents during traditional African processing of maize: Effect of iron contamination on bioaccessibility

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Abstract

a b s t r a c t The effect of the different unit operations of processing traditionally used to produce four maize foods commonly consumed in Africa on the nutritional composition of the products was investigated, using Benin as a study context. The impact of the processes on lipid, fibre, phytate, iron and zinc contents varied with the process. The lowest IP 6 /Fe and IP 6 /Zn molar ratios, the indices used to assess Fe and Zn bioavail-ability were obtained in mawè, a fermented dough. Analysis of maize products highlighted a significant increase in iron content after milling, as a result of contamination by the equipment used. Evaluation of iron bioaccessibility by in vitro enzymatic digestion followed by dialysis revealed that the iron contam-ination, followed by lactic acid fermentation, led to a considerable increase in bioaccessible iron content. Extrinsic iron supplied to food products by the milling equipment could play a role in iron intake in devel-oping countries.

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... Fractionation steps have shown to decrease not only chelating compounds such as PA and fiber, but also minerals including Fe and Zn. This is because both, chelating agents and minerals, are mainly in the germ and aleurone layer (Greffeuille et al., 2011;Cheah et al., 2020;Gannon and Tanumihardjo, 2014). For threshed maize intermediate and final products, large losses of PA and to a lesser extent Fe and Zn were observed due to the physical losses of germ and pericarp. ...
... No significant losses of Zn or Fe were observed in tortillas, most likely because during nixtamalization, only the outermost pericarp layer was removed, which is mostly composed of polysaccharides/hemicelluloses, whereas the aleurone and germ were not removed. Although intrinsic minerals can be reduced during processing, iron contamination of maize products has been found during postharvest treatments, such as harvesting, milling, cooking, under uncontrolled conditions (Greffeuille et al., 2011). Thus, the mineral content in tortillas could also come from the stone grinder. ...
... For ZBM varieties, %TR of PA in nixtamal and tortilla was 118.3% and 103.9%, respectively (Fig. 1 d). Since the dry matter losses were low and most of the germ remained in the dough, the PA content was as expected (Greffeuille et al., 2011). Between 0 and 35% PA reductions have also been reported; however, in this study, losses of PA in tortillas were not found. ...
Article
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High kernel-zinc maize varieties are available to consumers in several countries in Latin America to contribute to increase the zinc intake of their populations. Minerals, phytic acid and amino acids retention were measured after processing six maize varieties including three high kernel-zinc, one quality protein maize and two conventional maize. Grain for each variety was processed in duplicate into tortillas, arepas and mazamorra, common maize dishes in the region. To evaluate the effect of processing kernel-zinc maize varieties on zinc retention, varieties were grouped in zinc biofortified maize (ZBM) and non-ZBM. Iron, zinc, phytic acid, tryptophan and lysine concentrations in non-processed maize were 17.1–19.1 μg/g DW, 23.9–33.0 μg/g DW, 9.9–10.0 mg/g DW, 0.06–0.08% and 0.27–0.37%, respectively. In tortillas, the iron, zinc, phytic acid and lysine content did not change (p<0.05) compared to raw grain, while tryptophan decreased by 32%. True retention of iron in arepas and mazamorra was 43.9 and 60.0%, for zinc 36.8 and 41.3%, and for phytic acid 19.3 and 25.1%. Tortillas had higher zinc retention than arepas and mazamorra due to use of whole grain in the nixtamalization process. Therefore, to contribute to higher zinc intake, nixtamalized tortilla prepared with biofortified zinc maize is recommended. Additionally, promotion of whole grain flour to prepare arepas should be explored to enhance the intake of minerals that are usually confined to aleurone layers and germ.
... Evidence shows that there is a great deal of contaminant iron reaching our food mainly from the soil, milling equipment, cookware, and water throughout the food chain, as displayed in Fig. 1. Cereal grains contain contaminant iron mainly due to their contact with soil, tap water, leaching from iron/ steel surfaces during milling and food preparation (Baye, Mouquet-Rivier, Icard-Verniere, Picq, & Guyot, 2014;Greffeuille et al., 2011;Icard-Verniere et al., 2013;Teklu, 2017). For instance, the iron content of tef reported in literature widely ranges from 5 to 150 mg/100 g dm and this is attributed to contamination from soil, mostly during threshing. ...
... Despite these facts, only a few studies investigated the dietary significance of contaminant iron in different cereals and their products but eventually came up with conflicting conclusions. Greffeuille et al. (2011) revealed that contaminant iron in maize flour and its porridge contributed to 1.3% of the bioaccessible iron. Millet flour with high amounts of contaminant iron, coming from the soil, tap water, and milling equipment showed a lower iron bioaccessibility (2.4%) than the same millet flour with lower contaminant iron (11%). ...
... In contrast, the opposite was true for sorghum flour (Icard-Verniere et al., 2013). Greffeuille et al. (2011) speculated that differences in the extent of bioaccessibility of contaminant iron could be linked to the difference in forms and sources of contaminant iron. Ferric oxides and ferric hydroxides are generally considered the most common forms of contaminant iron in foods (Harvey, Dexter, & Darnton-hill, 2000). ...
Article
Background Iron, the building block of hemoglobin, plays a crucial role in facilitating tissue oxygen delivery. Iron deficiency anemia, a morbid health condition, is among the leading global health problems. In an attempt to control this, iron fortification, supplementation and dietary diversification strategies have been used. Researches show that plant-based food products, particularly in developing countries, contain an abundant amount of contaminant iron, i.e. non-endogenous plant iron. However, the nutritional significance or bioaccessibility of contaminant iron is not well characterized. Scope and approach In this review, the importance of contaminant iron in human nutrition is investigated with a special focus on contaminant iron sources, bioaccessibility, existing analytical techniques, and iron fortification's impact on gut microflora. Key findings and conclusions Plant-based Food products, particularly in developing countries, contain a great deal of contaminant iron originating from soil and processing equipment. Based on the existing literature, no concrete conclusion could be drawn regarding the bioaccessibility and/or nutritional benefits of contaminant iron highlighting the need for further studies. Whether the external labeling of stable iron isotopes method reliably differentiates and quantifies bioaccessible contaminant iron needs verification.
... Milling is traditionally done through stone grinders (now obsolete), mortar and pestle, steel plate mills, and increasingly by the power-driven hammer mill. [11,12] Light dishes are habitually served as a breakfast, while thick dishes are served as lunch or as dinner and others are reserved for special ceremonies, rituals or caring for ill or aged people, pregnant women or infants. [8,11] Consumer preference for maize in Africa is changing as many recipes use it in a combination with other grains such as wheat, sorghum, millet, barley and legumes/nuts. ...
... Plate mills are commonly used for wet grinding; the sharpness of the plate and the number of milling rounds minimize the chaff yield. [12,50] The use of plate mills has been reported to increase the iron content in dry and wet milled maize by 78-89% and 199%, respectively, due to the wear and tear of the grinding metal plate. The increase was suggested to be an enrichment, but the bioavailability of the extra iron was not established. ...
... The increase was suggested to be an enrichment, but the bioavailability of the extra iron was not established. [12] Traditional sourdough production uses spontaneous fermentation, which is uncontrolled. Sometimes backslopping is used to achieve a consistent and faster fermentation. ...
Article
Full-text available
In vast swathes of Sub-Saharan Africa, maize is the staple food with consumption of up to 450 g/person/day. Additionally, maize is used as a weaning food for infants as well as for special ceremonies, caring for the sick, aged and pregnant women. Malnutrition persists in regions with heavy maize consumption, partly due to compositional maize characteristics, nutrient loss during processing and consumer preferences. This paper reviews the traditional uses and processing of maize, opportunities and necessary improvements to ensure (micro)nutrient security. Better use of maize can enhance its contribution to meeting the dietary needs and livelihood of Africa’s growing populace.
... The average in vitro iron and zinc bioaccessibility was 6.5% and 11%, respectively. Iron bioaccessibility values of 0.3-4% have been reported by several authors after preparation of African fermented cereals (Baye et al., 2015;Baye et al., 2014;Baye et al., 2013;Greffeuille et al., 2011) while values of 5.6-7% ...
... The bioavailability of iron in fermented cereals can also be influenced by the presence of extrinsic iron which can become part of the food due to contamination from soil, dust, processing equipment and preparation procedures (Greffeuille et al., 2011). In particular, cereal grains that are associated with traditional threshing practices such as sorghum and millets may be highly contaminated with iron from soil. ...
Thesis
Cereals contribute to a substantial proportion of the iron and zinc requirements of low income groups yet they are of low iron and zinc content and bioaccessibility (proportion of minerals available for absorption) due to their high level of mineral binding compounds. Fermentation is commonly practiced for the preparation of cereal products in developing countries and has potential to improve iron and zinc bioaccessibility through the reduction of mineral binding compounds. The purpose of this PhD was to evaluate the potential of fermentation to improve the iron and zinc bioaccessibility of cereal based complementary porridges commonly consumed in Zimbabwe and Africa at large. Finger millet porridges fermented at the household level were of low iron and zinc content and bioaccessibility which could not meet more than 50% of the dietary requirements of children between the ages of 1-3 years. Fermented cereals from five locations in Zimbabwe showed differences in both mineral contents and bioaccessibility that could be attributed to varietal and agricultural influences. Presence of soil iron on some cereals from Chiweshe and Chiredzi could improve the nutritional status of populations subsisting on such cereals. Of interest was the low zinc content and bioaccessibility on all cereals despite their origin suggesting the probable existence of a higher risk of zinc deficiency than iron. Food-to-food fortification using local ingredients such as baobab fruit pulp and mopane worm coupled with cereal fermentation could improve mineral nutrition in developing countries.
... Consequently, Fe values as high as >150 mg/100 g were reported for teff (9) . Subsequent contamination with soil during open drying of grains or with metallic Fe screw-wares during milling have also been reported (11,12) . ...
... However, the source and the bioavailability of this contaminant Fe is rarely investigated. For instance, Fe from screw-ware during milling (metallic), ground water (soluble) and soil Fe are not expected to be of similar bioavailability (11,12,26) . Studies have found high Fe contents in cereal grains from Africa that are partly attributable to contamination with soil Fe (9,27) . ...
Article
Full-text available
Contamination of foods with extrinsic (soil) Fe is common in developing countries. However, the bioavailability of this extrinsic Fe and the extent to which it contributes to Fe nutrition remains unknown. The present study compared the bioavailability of laboratory- and field-threshed teff ( Eragrostisis tef (Zucc) Trotter ) to evaluate the bioavailablity of extrinsic soil Fe that resulted from the traditional threshing of the staple grain. Using sequential extraction, Fe was fractionated and its solubility was evaluated. The contribution of the additional extrinsic (soil) Fe to the Hb regeneration of Fe-depleted rats was evaluated using a rat Hb depletion–repletion assay. Weanling male Wistar rats ( n 24) were fed Fe-deficient diet for 21 d, and were then repleted for 14 d with diets: either laboratory-threshed teff (35 mg Fe/kg; n 8 ), field-threshed teff (35 mg intrinsic Fe/kg+ 120 mg soil Fe/kg; n 8 ), or FeSO 4 (control; n 8). Fe content of field-threshed teff (29·4 mg/100 g) was four times greater than that of the laboratory-threshed (6·7 mg/100 g) teff ( P <0·05). Soil contamination significantly increased the exchangeable, acid-soluble and reducible fractions obtained after sequential extraction. The relative biological value of the field-threshed teff (88 %) was higher than that of the laboratory-threshed (68 %) teff ( P <0·05). Soil Fe can contribute to Hb regeneration in Fe-deficient rats. Considering that contamination of foods with soil is common in Ethiopia and other developing countries, it needs to be accounted for in the design and implementation of fortification programmes to prevent excessive intakes. Human studies are needed to confirm the present findings.
... On the other hand, it was stated a decrease of PA of injera from 1050 to 340 mg/100 g representing a degradation rate of 68% when inoculated with L. buchneri MF58 but of 42% with that of backslop fermentations (25 o C, 48 hours) . Greffeuille et al. (2011) reported that the adverse effect of PA on iron absorption of plant-based food product can only be eliminated if the PA content is decreased to a level of less than 100 mg/100 g dm. ...
... Many researchers have tried to make associations between the exact amount of PA left after fermentation (or any other process) and the bioaccessibility of Fe and Zn. The adverse effect of PA on Fe bioaccessibility seems only to be eliminated by decreasing the PA content to a level below 100 mg/100 g dm (Greffeuille et al., 2011). Moreover, Hurrell (2004) suggested a degradation of more than 90% of the phytate content and/or even a complete dephytinization to reduce the PA:Fe molar ratio to a value < 1 or preferably < 0.4 for enhancing the Fe bioaccessibility. ...
Thesis
In this PhD study, nutritional and health importance of tef, an ancient cereal, was studied. Tef is a cereal originated in Ethiopia where it has been used as a staple cereal. Currently, this cereal is becoming popular in the western countries, however, there is scarcity of information regarding its nutritional and health benefits. This study focused on key nutritional issues in tef flour, injera, porridge and bread: phenolic content and antioxidant capacity, mineral content and bioaccessibility, starch digestibility, protein digestibility and its compliance as a gluten free ingredient. The results showed that tef contains higher Fe, Zn and Ca than other cereals and fairly high amount of digestible proteins. Tef also contains high phenolic content and antioxidant capacity. It is also in compliance with the European Union Food Regulation Directive as a gluten free cereal. Fresh traditional foods such as tef injera-pancake and porridges may cause high post prandial glucose level, while fresh conventional tef bread could only cause a moderate increase in blood glucose level.
... This process often results in nutrient loss from the original grain. A wide range of Zn loss can occur when whole maize grain is processed into flour: a study in Benin reported an 11% decrease in Zn when maize was ground into flours at local mills [41], Zn content decreased by 18% when maize was ground into the course flour product masa [42], while up to 57% of Zn was lost when maize flour was refined in Malawi [43]. FCTs also report variable differentials between the Zn concentration of maize grain and maize flour [44,27]. ...
... Most notably, the Zn concentration of maize flour sampled from market was only 10% of the median Zn concentration measured in whole maize grain collected from household farms (3.8 and 38.3 ppm Zn, respectively). Between 11-60% of this difference may be due to processing, which removes part or all of the grain germ and pericarp [43,41,28]. The remaining difference between Zn concentration in maize grain and in flour samples may be due to an underlying difference in nutrient concentrations of crops grown on household farms and sold at local markets. ...
Article
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Background Zinc (Zn) deficiency is one of the most common micronutrient deficiencies worldwide. Accurate estimates of Zn intake would facilitate the design and implementation of effective nutritional interventions. Objective We sought to improve estimates of dietary Zn intake by evaluating staple crop Zn content and dietary Zn consumption by children under the age of 5 in 9 rural districts of Uganda. Methods We measured the Zn content of 581 crop samples from household farms and 167 crop samples from nearby markets, and administered food frequency questionnaires to the primary caretakers of 237 children. We estimated Zn consumption using 3 sources of crop Zn content: (i) the HarvestPlus food composition table (FCT) for Uganda, (ii) measurements from household crops, and (iii) measurements from market crops. Results The Zn content of staple crops varied widely, resulting in significantly different estimates of dietary Zn intake. 41% of children appeared to be at risk when estimates were based on market-sampled crops, 23% appeared at risk when estimates were based on the HarvestPlus FCT, and 16% appeared at risk when estimates were based on samples from household farms. Conclusion The use of FCTs to calculate Zn intake overestimated the risk of dietary inadequacy for children who primarily consumed staple crops that were produced on household farms, but underestimated the risk for children who primarily consumed staple crops that were purchased at market. More information on the Zn content of staple crops in developing countries could lead to more accurate estimates of dietary intake and associated deficiencies.
... A different pH profile (pH vs time) along the GI tract as simulated in the model may have an effect on the experimental bioaccessibility (Minekus et al., 2014). Regarding this, various methodologies have been developed (Greffeuille et al., 2011;Minekus et al., 2014;Torres-Escribano et al., 2011), with the static model presenting digestive compartment distinction and complete digestive juices, including enzymes in all steps, being one of the most reliable systems (Cardoso, Afonso, Lourenço, Costa, & Nunes, 2015;Versantvoort, Oomen, Van de Kamp, Rompelberg, & Sips, 2005). More recently, these in vitro techniques for assessing human bioaccessibility have been subjected to significant improvements . ...
... The option for a centrifugation to separate the bioaccessible fraction may also be influential, particularly if there are significant amounts of elements soluble, but bound to high molecular weight compounds, whose absorption through the intestinal wall is low or absent. In this case, bioaccessibility may be overestimated and dialysability may bring advantage over solubility (Greffeuille et al., 2011). On the other hand, there may be chelating agents, such as phytates, that form insoluble complexes with the metal ions and reduce their absorption across the intestinal wall (Hurrell & Egli, 2010). ...
Article
The elemental composition of five species of green seaweeds (Chaetomorpha linum, Rhizoclonium riparium, Ulva intestinalis, Ulva lactuca, Ulva prolifera) grown in fish pond aquaculture systems were studied. The elemental bioaccessibility in these species was also investigated through the application of an innovative in vitro digestive model of the human gastrointestinal tract. It was observed that R. riparium had the highest levels of Mn, Sr, Cd, Sn, and I and that U. lactuca had the highest Ni and Cu concentrations. The daily amounts of dried green seaweed required for achieving specific dietary intakes were calculated, namely: 7 g of dried U. lactuca (for meeting Cu Recommended Daily Allowance, RDA); 173 g of dried U. lactuca (Zn RDA); 78 g of dried C. linum (Se RDA); 41 g of dried C. linum (Mo RDA); and 0.5 g of dried R. riparium (I Dietary Reference Intake, DRI). Concerning elemental bioaccessibility, Mn and Cu had the highest values, always above 50%, I values were in the lower range, between 14 and 31%. The elemental bioaccessibility range of R. riparium (31–100%) was higher than the ranges for other species, particularly C. linum (0–56%). The bioaccessibility results entailed higher quantities of dried seaweed for reaching dietary intakes: 10 g of dried U. lactuca (Cu RDA); 290 g of dried R. riparium (Zn RDA); and 2 g of dried R. riparium (I DRI). Accordingly, R. riparium is a very rich I source. This study showed the importance of taking into account bioaccessibility results in estimating dietary intakes.
... Lower iron bioaccessibility has also been observed in finger millet seed coat and pearl millet bran, when compared to the polished grains (Lesteinne et al., 2005;Krishnan et al., 2012). Variations in iron bioaccessibility were also documented in traditionally processed maize grains (Greffeuille et al., 2011). Improvement in bioaccessible iron in acid soaked endosperm rich fraction could be attributed to the decrease in phytate content and solubilization of insoluble fibre, Greffeuille et al. (2011) also observed improved iron bioaccessibility in maize after fermentation, and attributed this to the formation of lactic acid. ...
... Variations in iron bioaccessibility were also documented in traditionally processed maize grains (Greffeuille et al., 2011). Improvement in bioaccessible iron in acid soaked endosperm rich fraction could be attributed to the decrease in phytate content and solubilization of insoluble fibre, Greffeuille et al. (2011) also observed improved iron bioaccessibility in maize after fermentation, and attributed this to the formation of lactic acid. Salovaara et al. (2003) reported that solubility of non haem iron is mainly affected by pH and tartaric acid among the organic acids enhanced the bioaccessibility of iron in caco 2 cells mainly due to the physiologically suitable pH. ...
... Lower iron bioaccessibility has also been observed in finger millet seed coat and pearl millet bran, when compared to the polished grains (Lesteinne et al., 2005; Krishnan et al., 2012). Variations in iron bioaccessibility were also documented in traditionally processed maize grains (Greffeuille et al., 2011 ). Improvement in bioaccessible iron in acid soaked endosperm rich fraction could be attributed to the decrease in phytate content and solubilization of insoluble fibre, Greffeuille et al. (2011) also observed improved iron bioaccessibility in maize after fermentation, and attributed this to the formation of lactic acid. ...
... Variations in iron bioaccessibility were also documented in traditionally processed maize grains (Greffeuille et al., 2011 ). Improvement in bioaccessible iron in acid soaked endosperm rich fraction could be attributed to the decrease in phytate content and solubilization of insoluble fibre, Greffeuille et al. (2011) also observed improved iron bioaccessibility in maize after fermentation, and attributed this to the formation of lactic acid. Salovaara et al. (2003) reported that solubility of non haem iron is mainly affected by pH and tartaric acid among the organic acids enhanced the bioaccessibility of iron in caco 2 cells mainly due to the physiologically suitable pH. ...
Research
Pearl millet was decorticated to obtain a bran rich and endosperm rich fraction. The two fractions were soaked in solutions with varying pH. Pearl millet grains were germinated and steamed followed by decortication to obtain two fractions. It was observed that bran rich fractions contained high concentrations of iron, zinc, polyphenols, phytic acid, fibre and flavonoids. Soaking for short duration of 3 h did not result in major mineral losses but decreased the inhibitory factors which depended on the pH. Alkaline soaking decreased flavonoid content by 62.7% in the endosperm rich fraction, while acidic soaking decreased phytic acid content to the maximum in the bran rich fraction. Combination of treatments like germination and heat decreased the phytate content to the maximum in the endosperm rich fraction. Acidic conditions improved zinc bioaccessibility in the bran rich fraction (35%) and iron bioaccessibility (2.5%) in the endosperm rich fraction. Bran rich fraction from germinated grain also had enhanced bioaccessibility of both the minerals but comparatively lesser when compared to soaking under acidic conditions. Soaking the grain components under slightly less than neutral conditions also decreased some of the inhibitory factors and improved the zinc bioaccessibility to some extent in the bran rich fraction.
... Among other benefits, vitamin A is essential for the normal functioning of the visual system [16]. Mineral deficiencies in cereal fermented foods and methods to improve their bioaccessibility are relatively well covered [17] and are not discussed per se in this paper, except in relation with the infection status of the populations of developing countries. Despite some general claims, there is a surprising lack of research on the effect of lactic acid fermentation on the vitamin content of LAB-fermented cereal foods. ...
Article
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Cereal foods fermented by lactic acid bacteria are staples in many countries around the world particularly in developing countries, but some aspects of the nutritional and health benefits of traditional fermented foods in developing countries have not been sufficiently investigated compared to fermented foods in high-income countries. Today, malnutrition worldwide is characterized by a double burden, excess leading to non-communicable diseases like obesity or diabetes alongside micronutrient deficiencies. In addition, populations in developing countries suffer from infectious and parasitic diseases that can jeopardize the health benefits provided by their traditional fermented foods. Using examples, we argue that research on traditional fermented cereals in developing countries should focus more on their effect on inflammation and oxidative stress under conditions including infectious or non-infectious gut inflammation.
... The bioaccessibility of iron in fermented cereals can also be influenced by the presence of extrinsic iron which can become part of the food due to contamination from soil, dust, processing equipment and preparation procedures (Greffeuille et al., 2011;Icard-Vernière et al., 2013). In particular, cereal grains that are associated with traditional threshing practices such as sorghum and millets may be highly contaminated with iron from soil. ...
Article
The present study is an evaluation of iron and zinc bioaccessibility of fermented maize, sorghum, pearl millet and finger millet from five different locations in Zimbabwe. Iron and zinc contents ranged between 3.22 and 49.7 and 1.25–4.39 mg/100 g dm, respectively. Fermentation caused a reduction of between 20 and 88% of phytic acid (PA) while a general increase in soluble phenolic compounds (PC) and a decrease of the bound (PC) was observed. Bioaccessibility of iron and zinc ranged between 2.77 and 26.1% and 0.45–12.8%, respectively. The contribution of the fermented cereals towards iron and zinc absolute requirements ranged between 25 and 411% and 0.5–23% with higher contribution of iron coming from cereals that were contaminated with extrinsic iron. Populations subsisting on cereals could be more at risk of zinc rather than iron deficiency.
... In food processed using decorticated biofortified varieties, zinc could reach a moderate level of bioavailability, but this also depends on other technological processes than decortication used to prepare the food. Greffeuille et al. (2011) showed that the processes may have a positive effect on the phytate ⁄ iron and phytate ⁄ zinc molar ratios during traditional African processing of maize. In all cases, accompaniments that are consumed at the same time as cereal-based foods, such as vegetable sauces, must also be taken into account when evaluating the overall bioavailability of iron and zinc in the diet, as they can provide more iron and zinc, but also some phytate or other chelating factors. ...
... Fermentation is well known to increase minerals and amino acid levels in food samples. It degrades anti-nutritional factors like phytates and lead to availability of calcium, magnesium, phosphorus, zinc and iron (Greffeuille et al., 2011). Finger millet is a rich source of calcium (300 to 350 mg/100 g grain) and a good source of phosphorus and iron (Shahidi and Chandrasekara, 2013), hence higher levels of calcium in MP and MAP could be attributed to high calcium levels in millet. ...
Article
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In this study, sorghum-finger millet based complementary food incorporated with amaranth and pumpkin seed flour was formulated and the effect of fermentation on some of its characteristics was investigated. It was observed that fermentation significantly increased pasting temperature and decreased peak viscosity, breakdown and setback of the formulated foods. The foods had a final viscosity range of 831-2202 cP in non-fermented samples and 719-2135 cP in fermented samples. Formulated foods had a recommended consistency range of 1000–3000 cP except for Millet-Amaranth-Pumpkin, fermented Sorghum-Pumpkin and fermented Sorghum-Amaranth-Pumpkin. Protein solubility exhibited lowest solubility at isoelectric pH of 4 for non-fermented samples and between pH 4 and 6 for fermented samples. It was further observed that fermentation increased protein solubility. Threonine and lysine were found to be the most limiting amino acids in almost all samples. Results on mineral content showed potassium and magnesium to be the highest and higher than the reference levels set by FAO/WHO. Furthermore, high zinc levels were observed and calcium was highest in Millet-Amaranth-Pumpkin. Although the amino acid profile was found to be low, the formulated complementary foods meet other relevant nutritional requirements ideal for complementary foods
... On the other hand, it was stated a decrease of PA of injera from 1050 to 340 mg/100 g representing a degradation 68% when inoculated with L. buchneri MF58 but 42% with that of spontaneous fermentations (25°C, 48 h) [76]. Greffeuille et al. [77] reported that the adverse effect of PA on iron absorption of plant based food product can only be eliminated if the PA content is decreased to a level of less than 0.1 g/100 g dm. ...
Article
Full-text available
This review covers the nutritional significance of tef cereal as compared to other common cereals with emphasis on carbohydrate content and starch digestibility, protein content, iron and zinc bioavailability and antioxidant potentials. Tef is a gluten free cereal and contains the highest iron and calcium among other cereals. It has high micro- and macro- nutritional profile and is becoming globally popular in the healthy grain food chain. Tef starch has a high gelatinization temperature, an essential precondition in the preparation of low glycemic index foods. There are significantly conflicting reports of iron content of tef ranging from 5 to 150 mg/100 g dm. The traditional fermentation of injera reduced majority of the phytic acid but no significant change to mineral bioavailability was observed. This review indicated that studies on starch digestibility, protein characterization, amylase and protease inhibitors, mineral bioavailability and antioxidant potentials are needed to further explore the nutritional and health benefits of tef.
... Many researchers have tried to make associations between the exact amount of PA left after fermentation (or any other process) and the dialysability of Fe and Zn. The adverse effect of PA on Fe absorption/ dialysability seems only to be eliminated by decreasing the PA content to a level below 100 mg/100 g dm (Greffeuille et al., 2011). Moreover, Hurrell (2004) suggested a degradation of > 90% of the phytate content and/or even a complete dephytinization to reduce the PA:Fe molar ratio to a value < 1 or preferably < 0.4 for enhancing the Fe dialysability. ...
Article
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Abstract Tef [Eragrostis tef (Zucc.) Trotter], an ancient cereal mainly produced in Ethiopia, is increasingly getting higher acceptance in the global market because it is gluten free and has high iron content. The aim of this study was to evaluate the in vitro dialysability of Fe and Zn in a backslop fermented gluten free flat bread known as injera. The traditional fermentation caused up to 49–66% reduction of phytic acid (PA). Molar ratios of PA:Fe and PA:Zn decreased from 14 to 1 and from 63 to 19, respectively, after 120 h of fermentation. The total soluble fractions of Fe and Zn ranged between 11 and 38% and between 11 and 29%, respectively, after 120 h of fermentation. The dialyzable Fe content of the white varieties ranged between 3 and 9% after 120 h fermentation while no effect was observed for the brown varieties. The dialyzable Zn ranged between 2 and 11%, with only a clear effect of fermentation in one white variety. Consumption of tef could be a good source of Fe and Zn, but may not provide the absolute recommended daily Fe and Zn intakes.
... All of the RUTFs were designed to meet the WHO 2007 recommendations for RUTF mineral and vitamin levels, except for iron and zinc (23). To compensate for the higher phytic acid content in the FSMS-and MSMS-RUTFs and improve the phytic acid:iron and phytic acid:zinc molar ratio, we increased the concentration of iron and zinc in the SMS-RUTFs above the WHO-recommended concentrations (23)(24)(25)(26)(27); however, the iron concentrations surpassed target levels, which is most likely attributable to contamination associated with processing of the grain components (28). To improve iron bioavailability in the SMS-RUTF, we substantially increased the vitamin C content above the WHOrecommended minimum. ...
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Background: Development of more cost-effective ready-to-use therapeutic food (RUTF) is a global public health priority. To date, previous lower-cost recipes have been less effective than the standard peanut and milk (PM)-based RUTF, particularly in children aged <24 mo.Objective: We aimed to compare the efficacy of the PM-RUTF to a milk-free soya, maize, and sorghum (FSMS)-RUTF enriched with crystalline amino acids without cow milk powder and a milk, soya, maize, and sorghum (MSMS)-RUTF containing 9.3% skim cow milk powder.Design: This nonblinded, 3-arm, parallel-group, simple randomized controlled trial enrolled Malawian children with severe acute malnutrition.Results: In intention-to-treat analyses, FSMS-RUTF showed noninferiority for recovery rates in children aged 24-59 mo (Δ: -1.9%; 95% CI: -9.5%, 5.6%) and 6-23 mo (Δ: -0.2%; 95% CI: -7.5%, 7.1%) compared with PM-RUTF. MSMS-RUTF also showed noninferiority for recovery rates in children aged 24-59 mo (Δ: 0.0%; 95% CI: -7.3%, 7.4%) and 6-23 mo (Δ: 0.6%; 95% CI: -4.3%, 5.5%). Noninferiority in recovery rates was also observed in per-protocol analyses. For length of stay in the program (time to cure), both FSMS-RUTF in children aged 24-59 mo (Δ: 2.8 d; 95% CI: -0.8, 6.5 d) and 6-23 mo (Δ: 3.4 d; 95% CI: -1.2, 8.0 d) and MSMS-RUTF in children aged 24-59 mo (Δ: 0.2 d; 95% CI: -3.1, 3.6 d) and 6-23 mo (Δ: 1.2 d; 95% CI: -3.4, 5.8 d) were not inferior to PM-RUTF. FSMS-RUTF was also significantly better than PM-RUTF at increasing hemoglobin and body iron stores in anemic children, with mean hemoglobin increases of 2.1 (95% CI: 1.6, 2.6) and 1.3 (95% CI: 0.9, 1.8) and mean body iron store increases of 2.0 (95% CI: 0.8, 3.3) and 0.1 (95% CI: -1.1, 1.3) for FSMS-RUTF and PM-RUTF, respectively.Conclusions: FSMS-RUTF without milk is efficacious in the treatment of severe acute malnutrition in children aged 6-23 and 24-59 mo. It is also better at correcting iron deficiency anemia than PM-RUTF. This trial was registered at www.pactr.org as PACTR201505001101224.
... Cependant, la majorité des auteurs s'accordent pour souligner globalement les effets positifs de la fermentation sur la qualité nutritionnelle. Par exemple, il a été montré que la fermentation lactique permettait d'augmenter considérablement la bioaccessibilité des minéraux (Greffeuille et al., 2011). De ce fait, la sélection de souches bactériennes bien caractérisées permettrait de mieux contrôler la fermentation et d'améliorer certaines caractéristiques de l'aliment. ...
... Part of this Fe, particularly for teff, was attributed to an extrinsic source from soil contamination during traditional threshing (34) . Indeed, some portion of this extrinsic Fe may be bioavailable (35) and bioaccessible (36) . In addition, foods are frequently fermented and it has been shown that fermentation is effective to significantly reduce the phytate content of teff and other cereals to a level that can favour bioavailability (7,34) . ...
Article
Objective: Children from low-income countries consuming predominantly plant-based diets but little animal products are considered to be at risk of Fe deficiency. The present study determined the Fe status of children from resource-limited rural households. Design: A cross-sectional study. Setting: Twenty six kebeles (the smallest administrative unit) from six zones of the Amhara region, Ethiopia. Subjects: Children aged 54-60 months (n 628). Results: Grain, roots or tubers were the main dietary components consumed by 100 % of the study participants, followed by pulses, legumes or nuts (66·6 %). Consumption of fruit and vegetables (19·3 %) and meat, poultry and fish (2·2 %) was low. Children had a mean dietary diversity score of 2·1 (sd 0·8). Most children (74·8 %, n 470) were in the lowest dietary diversity group (1-2 food groups). Rate of any morbidity in the preceding 14 d was 22·9 % (n 114). Infection or inflammation (α1-acid glycoprotein >1·2 g/l) was present in 30·2 % (n 184) of children. Children had a high rate of stunting (43·2 %). Of the total sample, 13·6 % (n 82) of children were anaemic, 9·1 % (n 57) were Fe deficient and 5·3 % (n 32) had Fe-deficiency anaemia. Fe-deficiency erythropoiesis was present in 14·2 % (n 60) of children. Conclusions: Despite consuming a predominantly plant-based diet and little animal-source foods, there was a low prevalence of Fe-deficiency anaemia. This illustrates that dietary patterns can be inharmonious with Fe biochemical status; thus, Fe-related interventions require biochemical screening.
... Iron content is significantly increased in invitro study from 2 to 7 mg/100g in the flour after milling [30]. In another recent study, increase in iron content ranging from 43 to 138% have been measured between maize grains and flours, which increased with milling intensity [15]. A study comparing the iron contents of rice flour and polished rice from the same Thai market show a difference in iron content of 28.6 mg/100 g, which was attributed to contamination of whish 60 % iron was metal particles originating from the miller as it was manifested by strong magnet [17]. ...
Article
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Human can ingest extrinsic iron either involuntarily or deliberately. Contaminant iron from different sources like soil, processing equipment etc. in foods may lead to overestimation of the satisfaction of iron requirement while iron deficiencies remain a widespread health problem. The principal objective of this article is to review the existing invitro and invivo studies on contaminant iron bioaccessibility and bioavailability. The majority of the research findings, in both cases invitro and invivo, that are reviewed under this article suggest that soil contamination/geophagy does not enhance iron status and may even lower it in some cases. However, the mechanisms and degree to which geophagic substances adsorb or inhibit iron absorption remain unclear and with these circumstances it would be difficult to conclude that geophagy interferes with iron absorption. Few articles suggest that contaminant iron from soil and processing equipment could be a good source of dietary iron and iron bioavailability could be possibly enhanced with the combined effect of contamination and processing more specifically fermentation. However, more invivo contaminant iron bioavailability studies using golden method “rat hemoglobin repletion efficiency” should be conducted before drawing any conclusion on contaminant iron bioavailability since it depends on multiple effects that could not be covered under any of invitro iron bioavailability/bioaccessibility tests.
... The average in vitro iron and zinc bioaccessibility was 6.5% and 11%, respectively. Iron bioaccessibility values of 0.3-4% have been reported by several authors after preparation of African fermented cereals (Baye et al., 2015(Baye et al., , 2014(Baye et al., , 2013Greffeuille et al., 2011;Matuschek et al., 2001;Towo et al., 2006) while values of 5.6-7% (as solubility) have been reported for zinc (Kayodé et al., 2006). The lack of improvement in mineral bioaccessibility after processing could be because PA as IP6 was not degraded to lower forms of inositol phosphate after processing. ...
Article
The aim of the present study was to explore the effect of traditional fermentation and cooking on mineral binders and subsequent bioaccessible iron and zinc contents of finger millet sour porridge consumed in Ushe communal area in Zimbabwe. Porridge products prepared from four traditional varieties of finger millet were collected and analyzed for proximate composition, mineral binders and subsequently in vitro iron and zinc bioaccessibility. Compared to the raw materials, phenolic compounds and condensed tannins were reduced by up to 41% and 35% respectively while phytic acid was reduced by 22 − 54% in one variety only. Iron and zinc bioaccessibility was 6% and 13% respectively, in the porridges and no improvement in bioaccessibility was observed as a result of processing as such bioaccessible iron and zinc contents only met less than 50% of the recommended daily intakes for children aged 9-11 months. A multidisciplinary approach is urgently needed to improve the iron and zinc contents and bioaccessibility of cereal based porridges from developing countries.
... Interestingly, zinc and manganese were not found in the substrate but were detected in beverages fermented with single LAB cultures and the co-culture of yeast and L. acidophilus, respectively. It is known that fermentation has great importance in the improvement of the mineral content of cereal foods, because the degradation of anti-nutritional phytate during fermentation by bacteria led to the availability of calcium, magnesium, phosphorus, zinc, and iron (Greffeuille et al., 2011;Oyarekua, 2011;Sanni et al., 1999). ...
... The iron content of the tamarind seed increased by approximately 33% after the 3rd day of fermentation. Previous research found that fermentation increased the availability of iron and zinc (Greffeuille et al., 2011). However, it is also possible that the increase in iron may be due to the mineral content of the water used for fermentation procedure. ...
Article
Tamarind seed is an underutilized legume which can potentially be used as a food condiment. In this study, tamarind seed was fermented using the conventional traditional method of iru (daddawa) production. Samples withdrawn at intervals of 24 h were tested for proximate composition, antinutrients, mineral profile, and other physicochemical properties using standard methods. Protein, fat and carbohydrates were the major nutrients in the tamarind seed before and after fermentation. Phosphorus was the major mineral element of the raw (0.97 mg/100 g) and fermented (0.96–1.06 mg/100 g) tamarind seed. Fermentation substantially decreased the phytic acid contents (approx. 50%), tannin contents (approx. 75%) and trypsin inhibitor activity (approx. 86%). Bacillus subtilis, Bacillus licheniformis, and Bacillus pumilus were isolated as the organisms fermenting the tamarind seed. Fermented tamarind seed can be potentially used as a condiment for seasoning foods. However, future studies such as consumer acceptability are required to determine the acceptability of the fermented tamarind seed by potential consumers.
... For this reason, they often form the natural inoculum, together to fungal strains, of fermented cereal gruels commonly consumed in many rural societies worldwide (Nout, 2009). Fermentation of cereal-based beverages, as well as other food substrates, by LAB has been shown to improve protein digestibility (Holzapfel, 1997;Taylor & Taylor, 2002), increase nutritional bioavailability of minerals and other micronutrients (Agarry, Nkama, & Akoma, 2010;Greffeuille et al., 2011), prolong shelf life (Angelov et al., 2006;Gupta, Cox, & Abu-Ghannam, 2010), and finally enhance organoleptic qualities (Nionelli et al., 2014;Peyer, Zannini, Jacob, & Arendt, 2015). ...
Article
Today’s consumer demands functional, healthy and diversified food products that satisfy nutrition-related conditions such as food intolerances, allergies and malabsorption, and lifestyle choices, e.g. vegetarianism, veganism, low-fat or low-salt. Cereal-based beverages have been tested as functional and probiotic foods because of their nutritious and health-promoting properties, e.g. soluble fibres and phytoestrogens. A way to add functionality and improve the low organoleptic attributes of raw cereals is through fermentation using lactic acid bacteria (LAB). The use of starter cultures with known flavour- and texture-enhancing properties offers a promising tool for in situ product enhancement, innovation and diversification of cereal-based beverages.
... Extruded SMS had significantly higher amounts of iron (15.03 mg/100 g; p<0.001) but lower amount of PA (0.897 g/100 g; p<0.001) than raw SMS (4.27 mg/100 g and 1.09 g/100 g for iron and PA respectively) ( Table 3). Iron contamination from equipment during milling has been reported and is attributed to frictional wear and tear of the moving mill parts [27]. Because SMS processing was done in equipment traditionally used for fortified blended foods, the process steps that involve friction such as extrusion and milling are likely to have led to iron contamination, with consequent elevation of iron content in extruded SMS. ...
Article
Efficacy and cost of nutritional supplements are critical in addressing malnutrition. Use of cheaper and locally available ingredients in manufacturing ready-to-use foods (RUF) can potentially reduce cost and increase access to supplements in resource-poor settings. Soy protein concentrate (SPC) is a cheaper source of protein and can potentially replace the more expensive milk powder in RUF. However, SPC contains phytic acid (PA) which inhibits mineral bioavailability. PA may be degraded by the enzyme phytase. This study aimed to determine the effect of replacing skim milk powder (MP) with SPC and of added phytase on bioavailability of iron and zinc in soybean-maize-sorghum RUF. RUF samples were made using either SPC or MP. Phytase was added to food samples with either low (<5%) or high (>50%) moisture prior to estimation of bioavailability of iron and zinc by in vitro dialysability. Compared to samples with MP, SPC-based foods had significantly higher content of PA (0.84 g/100 g vs. 0.57 g/100 g; p<0.001); lower bioavailability of iron (2.79% vs. 4.85%; p<0.001) and lower zinc bioavailability (3.61% vs. 8.69% for zinc; p<0.001). After one hour of incubation at 35°C, 68% of PA in high-moisture foods and 10% of PA in low moisture foods were degraded. The data indicate that replacing MP with SPC in SMS RUF increases PA content with subsequent reduction of bioavailability of iron and zinc. Added phytase significantly reduces PA content in high moisture foods and may potentially remain active in the Stomach where moisture is high. Adding such a phytase could be a promising approach to increase iron and zinc bioavailability from SMS RUFs and provide cheaper locally produced formulations for addressing malnutrition in resource-poor settings.
... Some African cereal grains are purported to contain high amounts of iron, but a significant amount of this iron is contamination iron most of which has been found to be non-bioavailable. (128,161,173) Several studies have demonstrated an improvement of iron and zinc bioavailability after using biofortified grains, iron and zinc fortified flours, and addition of ascorbic acid. (36,113,174,175) The additive effects of these strategies along with fermentation may be able to overcome the effect of mineral deficiencies in Africa. ...
Article
Many weaning and complementary foods in Africa are plant based thus are not good sources of bioavailable iron and zinc owing to the presence of anti-nutritional factors, in particular phytic acid, phenolic compounds and to some extent dietary fiber. Several strategies are being developed to increase levels of bioavailable iron and zinc in plant based diets. These strategies range from fortification, biofortification, dietary diversification and use of household processing methods such as soaking, cooking, germination and fermentation. Fermentation poses a great potential as a significant amount of these foods in Africa involve a natural fermentation step. Exploration of this process could offer a more economical and sustainable way to reduce iron and zinc binders and consequently increase the bioavailability of the minerals in diets consisting of fermented cereals.
... van Jaarsveld, personal communication, September 2014). Contamination iron, as was probably present in the pumpkin leaves, has been found to not be bioaccessible [29]. The amaranth and spiderplant-fortified maize porridge meal provided the most bioaccessible iron compared with all the other dishes and meals. ...
Article
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The aim of this study was to determine the mineral nutritive value of different traditional African green leafy vegetable (GLV) dishes and their composite meals with fortified and unfortified maize porridge. The mineral (iron, zinc, and calcium) and antinutrient (phytate, total phenolics, and tannins) contents and in vitro bioaccessibility of iron and zinc were analyzed. The iron and zinc contents and bioaccessibilities were used to calculate contribution these dishes and meals could make toward the recommended daily requirements and absolute requirements of vulnerable populations. It was found that the GLV dishes contained average amounts of zinc (2.8-3.2 mg/100 g, dry base [db]), but were high in both iron (12.5-23.4 mg/100 g, db) and antinutrients (phytate 1420-2089 mg/100 g, db; condensed tannins 105-203 mg/100 g, db). The iron bioaccessibility and amount of bioaccessible iron ranged between 6.7% and 45.2% and 0.9 and 5.11 mg/100 g, db, respectively. The zinc bioaccessibility and amount of bioaccessible zinc ranged between 6.4% and 12.7% and 0.63 and 1.63 mg/100 g, db, respectively. Importantly, although compositing the GLV dishes with fortified maize porridges decreases the iron and zinc contents, because of the low antinutrient content of the maize meal, the amount of bioaccessible iron and zinc in the meal increases. Copyright © 2015 Elsevier Inc. All rights reserved.
... Iron is physiologically important micronutrient, acts as enzyme activator, as oxygen carri er in nitrogen fixation and is required for biological redox systems (Römheld and Marschner, 1990). It also interferes with human health and increases the bio accessibility in maize even if taken from multiple environmental sources (Greffeuille et al., 2011). Copper is also important in lignification process, pollen maintenance and with redox systems (Marschner, 1995). ...
... The area is mainly industrial and residential with no space for cultivation, hence this work examine the direct deposition on the food. Corn is eaten by people of all ages in many African countries in many traditional forms, meat in form of barbecue is eaten by all classes of people, while plantain is a major food eaten all over the world a ter rice, corn and milk [30,31]. ...
... The iron (3.1-3.7 mg/100 g), magnesium (0.11-0.15 mg/100 g) and zinc (2.1-2.9 mg/100 g) contents increased slightly after fermentation. The apparent increase in iron in amahewu after fermentation may be attributed to the destruction of antinutritional factors such as phytate which bind to iron and thus making it readily assayable (Greffeuille et al., 2011;Khetarpaul, Goyal, & Garg, 2005). The iron and zinc contents of PBM amahewu in this study are relatively higher than values in the literature (Oikeh et al., 2004;Oikeh, Menkir, Maziya-Dixon, Welch, & Glahn, 2003;Oikeh, Menkir, Maziya-Dixon, et al., 2003;Š imić et al., 2009). ...
Article
Amahewu is a traditional fermented beverage made from white maize that is widely consumed in South Africa. In this study, amahewu was prepared from provitamin A-biofortified maize (PBM) and different inocula and the nutritional properties of the beverage were assessed using standard methods. The amahewu samples were prepared by fermenting maize porridge using lactobacillus starter culture (LSC), wheat bran (WB) and malted provitamin A maize (MM) together with either MM or WB. The inoculum types did not substantially influence the overall composition of amahewu. Carbohydrate (82%) followed by protein (12%) were the major nutrients in all samples. However, inoculating amahewu beverage with LSC substantially reduced the fermentation time. Iron, zinc, and lysine contents increased slightly after fermentation, especially in the sample with added LSC. Protein digestibilities of amahewu samples also increased slightly after fermentation. The β-carotene contents (approx. 1.8 μg/g) were very similar across amahewu samples and these were substantially retained after fermentation. Hence, PBM may be a better alternative to white maize for the preparation of amahewu beverage with improved nutritional quality.
... Also, it was observed that the unit operations (Milling to form a slurry) and the duration (Steeping for 48 h) in Figure 1 aided phytate content reduction (91). This reduction is in accordance with the observations (21,49,(92)(93)(94). Table 7 presents the sensory attributes of ogi porridge from biofortified PVA genotypes and landrace yellow maize. ...
Article
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Provitamin-A maize (PVA) with increased carotenoid content obtained through conventional breeding techniques has been largely successful in sub-Saharan Africa. This resulted in a need to evaluate their susceptibility, retention, and nutritional content during processing into local foods. This study evaluated the chemical, carotenoid composition, and retention of PVA, the phytic acid content in ogi powder, and the sensory perception of ogi porridge produced traditionally from the three novel PVA maize genotypes (PVA SYN HGAC0 Maize 1; PVA SYN HGBC0 Maize 2; and PVA SYN HGBC1 Maize 3) and one yellow maize variety (control). Chemical composition analyses showed significant differences (p < 0.05) in all parameters. The PVA ranged from 5.96 to 8.43 μg/g in Maize 2 and 3 before processing while the true percentage retention after processing into ogi powder ranged from 20.25 to 37.54% in Maize 1 and 2, respectively. In addition, there was a reduction in the phytate content of ogi powder, and Maize 2 contained the lowest (2.78 mg/g from 4.09 mg/g). Maize 2 genotype had the highest vitamin A contribution; it can meet 18.3% of the vitamin A requirements in children while in adult males and females (>19 years), 6.2 and 7.7%, respectively. Sensory evaluation showed that the ogi 3 porridge (Maize 3) was the most acceptable, followed by Maize 2. In conclusion, Maize 2 had the highest PVA, true retention of carotenoid, vitamin A contributions, and the second most acceptable ogi porridge with the lowest phytate content.
... Some authors reported that exogenous iron from pots and mills can be added to the food during processing (Adish et al., 1999;Hama-Ba et al., 2019). Greffeuille et al. (2011) observed this contamination after maize milling into flour. The processing steps before frying did not lead to a significant reduction of zinc, calcium and magnesium content in both doughnut types. ...
Article
Doughnuts made from cowpea, a highly nutritious pulse, are frequently consumed in West Africa. As processing may affect their nutritional composition, cowpea processing into two doughnut types (ata and ata-doco) was characterized, and samples collected from 12 producers in Cotonou, Benin. Proximate composition, folate, mineral, phytate, and alpha-galacto-oligosaccharide contents were determined in the raw material, intermediate products, and doughnuts. Mass balance was assessed during ata production to monitor folate and alpha-galacto-oligosaccharides distribution, and to determine what steps most influenced their concentration. Ata was prepared with dehulled-soaked seeds, and ata-doco with whole or partially dehulled, non-soaked and dry-milled seeds. After both types of doughnuts production, lipid content increased by 11–33 times compared with raw seeds, due to oil absorption during deep-frying. Milling led to an increase of iron content by 50–57 % (ata) and 21–75 % (ata-doco production). Alpha-galacto-oligosaccharide contents decreased by 22–57 % after whipping during ata-doco, but not during ata production. The mass balance assessment showed significant reductions of folate (-50 %) and alpha-galacto-oligosaccharides (-33 %) after dehulled seed washing and soaking during ata production. This study showed that the impact of traditional processing on the nutritional value of cowpea-based doughnuts is strong, but highly variable depending on the doughnut type and producers’ practices.
... However, the market is developing and products are changing. Furthermore, fermentation has been shown to improve the protein digestibility (Holzapfel, 1997;Taylor and Taylor, 2002), likewise, the bioavailability of minerals and other micronutrients (Greffeuille et al., 2011;Watzke, 1998). Plants are a superior source for nutrients like vitamins, dietary fibers, antioxidants, and flavonoids, which have shown nutritious and health-promoting properties. ...
... Additional contamination could be due to the use of water traditionally stored in metal tanks. Dust during sundrying of the grains, if any, and the use of rusty cooking utensils (35)(36)(37) are also frequent causes of iron contamination. ...
Article
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Biofortification is among the food-based strategies, recently implemented and still in development, to fight micronutrient deficiencies. Three cereal-based traditional dishes of Sub-Saharan Africa (tô paste, pancakes, and gruel) prepared from one local (Gampela), or two biofortified (GB 8735 and Tabi) varieties of millet were assessed for their (i) acceptability by local consumers, (ii) iron and zinc absorption predicted by phytate-to-mineral molar ratios and (iii) contribution to the iron and zinc requirements of young children. Tasters preferred the color, texture, and taste of dishes prepared with the local variety, whether or not the grains were decorticated. Hedonic and preference tests showed no significant difference between the two biofortified varieties, but the cooks reported different behaviors during processing. Biofortified millet contained up to two times more iron than the local variety, reaching 6.5 mg iron/100 g dry matter. Iron and zinc contents remained higher in biofortified varieties even after decortication. Iron content in the dishes was highly variable, depending on iron loss and potential contamination during processing. The phytate-to-mineral molar ratios of all dishes indicated low iron absorption, independent of the millet variety, but improved zinc absorption in dishes prepared with biofortified varieties. The contribution of a dish prepared with one of the two biofortified millet varieties to the recommended iron and zinc intakes for 6–11-month-old children was estimated to be about 5 and 7%, respectively, compared to 2 and 4% for the same dish prepared with local millet. For 12–23-month-old children, the contribution to the recommended intakes was estimated to be about 14 and 12% with biofortified millet, respectively, and about 6 and 7% with local millet. The use of biofortified millet varieties could be complementary to food diversification strategies to increase iron and zinc intakes. As in Ouagadougou, cereals are eaten in different forms by young children several times per day, iron and zinc intakes could be improved in the long term by using the biofortified varieties of pearl millet.
... The challenges will be to develop better starter cultures targeted indigenous sub-Saharan African fermented food and beverages and to optimize the processing. To achieve this, several studies have been carried out to study the biochemical and microbiological changes which occur during processing including information on nutritional value and consumer preferences (Halm et al., 1996;Mugula et al., 2003b;Edema and Sanni, 2008;Padonou et al., 2010;Greffeuille et al., 2011;Akabanda et al., 2013;Houngbédji et al., 2018). Some of these studies have demonstrated that when the yeasts are combined in consortia it makes the fermented products more appealing. ...
Article
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Indigenous fermented food and beverages represent a valuable cultural heritage in sub-Saharan Africa, having one of the richest selections of fermented food products in the world. In many of these indigenous spontaneously fermented food and beverages, yeasts are of significant importance. Several factors including raw materials, processing methods, hygienic conditions as well as the interactions between yeasts and other commensal microorganisms have been shown to influence yeast species diversity and successions. Both at species and strain levels, successions take place due to the continuous change in intrinsic and extrinsic growth factors. The selection pressure from the microbial stress factors leads to niche adaptation and both yeast species and strains with traits deviating from those generally acknowledged in current taxonomic keys, have been isolated from indigenous sub-Saharan African fermented food products. Yeasts are important for flavor development, impact shelf life, and nutritional value and do, in some cases, even provide host-beneficial effects. In order to sustain and upgrade these traditional fermented products, it is quite important to obtain detailed knowledge on the microorganisms involved in the fermentations, their growth requirements and interactions. While other publications have reported on the occurrence of prokaryotes in spontaneously fermented sub-Saharan food and beverages, the present review focuses on yeasts considering their current taxonomic position, relative occurrence and successions, interactions with other commensal microorganisms as well as beneficial effects and importance in human diet. Additionally, the risk of opportunistic yeasts is discussed.
... However, cereals contain anti-nutritional-factors (e.g., phytic acid, which is a mineral chelator), and some nutrients that are poorly digested [1]. Fermentation can improve nutritional value [2], and functional and sensorial properties [3] of cereals. A larger part of cereal products in the world is fermented to achieve different kind of beverages and dough. ...
Article
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This review describes the technical and functional role of exopolysaccharides (EPSs) in cereal-based, yogurt-like beverages. Many microorganisms produce EPSs as a strategy for growing, adhering to solid surfaces, and surviving under adverse conditions. In several food and beverages, EPSs play technical and functional roles. Therefore, EPSs can be isolated, purified, and added to the product, or appropriate bacteria can be employed as starter cultures to produce the EPSs in situ within the matrix. The exploitation of in situ production of EPSs is of particular interest to manufacturers of cereal-base beverages aiming to mimic dairy products. In this review, traditional and innovative or experimental cereal-based beverages, and in particular, yogurt-like beverages are described with a particular focus in lactic acid bacteria (LAB’s) EPS production. The aim of this review is to present an overview of the current knowledge of exopolysaccharides produced by lactic acid bacteria, and their presence in cereal-based, yogurt-like beverages.
... The amount of alkali consumed and the enzymatic digestion time are recorded, which can illustrate the lipid digestion rate to some extent. In addition, a dialysis bag has also been employed as a simplified model of an epithelial barrier to evaluate the potential bioavailability of polyphenols and minerals [108,109]. The dialysis bag, which normally contains NaHCO 3 , is sealed and immersed into the digesta phase; the dialysate in the bag is then considered to be the soluble compounds that are available for further uptake. ...
Article
During the past 50 years, there has been increased interest in liposomes as carriers of pharmaceutical, cosmetic, and agricultural products. More recently, much progress has been made in the use of surface-modified formulas in experimental food matrices. However, before the viability and the applications of nutrients in liposomal form in the edible field can be determined, the digestion behavior along the human gastrointestinal tract (GIT) must be clarified. In vitro digestion models, from static models to dynamic mono-/bi-/multi-compartmental models, are increasingly being developed and applied as alternatives to in vivo assays. This review describes the surface interactions of liposomes with their encapsulated ingredients and with external food components and updates the biological fate of liposomes after ingestion. It summarizes current models for the human stomach and intestine that are available and their relevance in nutritional studies. It highlights limitations and challenges in the use of these models for liposomal colloid system digestion and discusses crucial factors, such as enzymes and bile salts, that affect liposomal bilayer degradation.
... Genetic variation in maize grain for Fe and Zn reported since 2000 is presented in Table 1. Higher values of Fe reported by some researchers may be attributable to Fe contamination from the soil, metal parts, dust, rubber products (especially silicon and neoprene), paint, and gloves used during harvesting, sample preparation, handling, and grinding or milling processes (Pfeiffer and McClafferty, 2007;Greffeuille et al., 2011;Joy et al., 2015). ...
Article
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Maize (Zea mays L.) is the third most important cereal in the world and the most important food security crop in sub-Saharan Africa. Maize provides energy and micronutrients. Deficiencies of the essential micronutrients Zn and Fe are fifth and sixth ranked among the top 10 most important risk factors for conditions such as anemia, low cognitive functioning, and impaired immune system (Fe deficiency) and diarrhea, skin inflammation, and recurrent infections (Zn deficiency) in humans, affecting more than two billion people worldwide. Poverty, lack of access to balanced diets and awareness, and low phytoavailability and bioavailability of these nutrients are major reasons for deficiencies. Breeding for mineral-rich maize is a sustainable and cost-effective approach to reduce micronutrient deficiencies. Since 2004, there has been significant progress in improving maize for Zn content. The aim of this review was to capture recent developments, trends, and progress in maize Fe and Zn biofortification and to identify challenges and ways to overcome them. HarvestPlus has set target levels for Fe (60 mg g⁻¹) and Zn (38 mg g⁻¹) in maize. Zinc target levels have been reached, but conventional breeding alone cannot enhance Fe to the recommended levels. Techniques such as oligo-directed muta-genesis, reverse breeding, RNA-directed DNA methylation, and gene editing could be used in future to speed up maize Fe biofortification. Additional research is required on Fe and Zn bioavailability in maize products, and on interactions of Fe and Zn with Ca and phytate and their influence on absorption, to better understand the underlying mechanisms. © Crop Science Society of America | 5585 Guilford Rd., Madison, WI 53711 USA All rights reserved.
... Fermentation is well known to increase minerals and amino acid levels in food samples. It degrades antinutritional factors like phytates and leads to the availability of calcium, magnesium, phosphorus, zinc, and iron [49]. These results were in agreement with those reported by Adegbehingbe [50] in the effect of single starter cultures on the mineral contents of fermenting 'ogwo,' a fermented gruel from sorghum-Irish potato mixture. ...
Article
Green leafy vegetables have low β-carotene bioavailability, which we hypothesised to be, at least in part, due to high contents of fibre, minerals, and phenolics. We investigated the effects of pectin (40-120 µg/mL), iron (50-150 µg/mL), ferulic acid (30-90 µg/mL) and catechin (50-150 µg/mL), in a model system, on β-carotene micellization (in vitro digestion) and intestinal absorption (Caco-2 cell model). Iron, pectin, ferulic acid and catechin on average, reduced (p<0.05) β-carotene micellization (1.49±0.05 µmol/L) by 66.9, 59.3, 43.2 and 51.7%, respectively. Iron reduced micellization by precipitating bile salts from solution and ferulic acid and catechin by inhibition of pancreatic lipase. β-carotene uptake by Caco-2 cells (2.63±0.22%) was reduced (p<0.05) by 37.4, 70.1, 77.0 and 75.1%, respectively, when digested with pectin, iron, ferulic acid or catechin. However, when individual test compounds were added to already micellized β-carotene, they did not inhibit β-carotene uptake. The large reductions in β-carotene micellization observed in vitro, warrant further investigation in humans using model green leafy vegetable systems to elucidate their relevance under real-life conditions.
Chapter
The health advantages of bioactive compounds and nutrients are based on intake levels and the amount of these compounds that become bioavailable and bioaccessible. The determination of bioactive compounds directly in food is not sufficient to evaluate the bioavailability and bioaccessibility and consequently their effects in vivo, since the compounds reaching the blood system result from a complex digestion process. Bioavailability is assessed by in vivo methodologies using gastrointestinal digestion, absorption, metabolism, tissue distribution, and bioactivity. In vitro methodologies allow for determining the bioaccessibility of the bioactive compounds and nutrients through liberation from the food matrix, simulation of gastrointestinal digestion, and assimilation by intestinal epithelium. This chapter presents the similarities and differences between the distinct techniques used to quantify bioavailability and bioaccessibility, as well as a brief description of the methodologies applied to determine different bioactive compounds and nutrients.
Article
Plant-based foods are gaining popularity and the market is developing fast. This trend is based on several factors, like the change of lifestyle, interest in alternative diets, and the increasing awareness about sustainable production of food and especially proteins. Plant-based dairy substitutes can serve as an option to traditional food products, meeting many of these interests. However, the market is in its infancy and needs to progress. Trends show, that the market will change from being focused on mainly soya, almond and rice-based products, due to their unsustainable farming, and nutritional concerns, like genetic modification and low protein content. The market is likely to shift towards alternative plants to meet consumers' needs and desire for healthy, flavourful and intriguing products. In this regard, the aspect of allergy-free, like gluten-free products gain in importance. Research studies are approaching the nutritional quality of plant-based dairy substitutes, such as improving the protein quality and glycaemic properties. Furthermore, the application of these products or plant proteins as functional ingredients or substitutes for cow's milk in dairy products like cheese and yoghurt are disseminated. However, there is still a need for much more diversified studies in order to overcome stability, textural, nutritional and sensory problems.
Thesis
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Durch ihre Umwelt- und Nährwertvorteile erweckten Afrikanische indigene Blattgemüse – „African Indigenous Vegetables“ (AIV) in letzter Zeit Aufmerksamkeit als „Supergemüse“ (Cernansky 2015). Da mehrere Spezies aus unterschiedlichen botanischen Familien innerhalb der AIVs vertreten sind, ist ein besseres Verständnis Spezies spezifischer Eigenschaften, wie z.B. Ernährungswert und agronomischem Management nötig, um diese Vorteile voll ausschöpfen zu können. In dieser Arbeit haben wir Afrikanisch indigene Blattgemüsearten aus fünf Familien, inklusive C3 and C4 Spezies und Leguminosen und nicht-Leguminosen (Brassica carinata/Cruciferae - Ethiopian Kale, Amaranthus cruentus/Amaranthaceae - Amaranth, Vigna unguiculata/Leguminosae - Cowpea, Solanum scabrum/Solanaceae - African Nightshade, Cleome gynandra/Capparaceae - Spiderplant) mit einer importierten und in Kenia häufig angebauten Gemüseart (Brassica oleracea acephala/Cruciferae - Exotic Kale) verglichen. Wir betrachteten die Pflanzenarten hinsichtlich ihrer Konzentrationen an wertgebenden und toxischen Elementen in Blättern als Index für den Nährwert, ihrer Reaktionen auf unterschiedliche zur Verfügung gestellten Mengen und Formen an Phosphor (P) als Index für die Adaptation an suboptimale chemische Bodenbedingungen und ihre erntebedingten Nährstoffausfuhren aus dem Boden als Index für den Düngerbedarf. Die Arbeit war in das interdisziplinäre Forschungsprogramm HORTINLEA (Horticultural Innovation and Learning for Improved Nutrition and Livelihood in East Africa) eingebunden.
Article
The establishment of the INFOGEST in vitro static digestion method, a standardized international consensus, was an important milestone in the field of food digestion. We evaluated the contribution of iron and zinc in reagents used in the INFOGEST method in relation to sample iron and zinc and the potential interference of reagent-derived iron and zinc with bioaccessibility measurements. In most cases, reagent-derived iron and zinc contributed more than 50% of the total iron or zinc in the digesta containing selected cereals and legumes. Moreover, the chemical behaviour of reagent-derived iron and zinc was matrix dependent such that the application of a blanket blank correction was not appropriate. We therefore propose an improved approach involving isotopic labelling of reagent iron and zinc in order to discriminate between reagent-derived and sample-derived iron and zinc in each matrix. This stable isotope approach could improve the accuracy and reliability of iron and zinc bioaccessibility studies.
Chapter
The probiotic sector witnessed a surge in research on the role of plant-based nondairy matrices in the creation of novel functional beverages for improving human health. Dairy products are excellent vehicles for the delivery of probiotics; however, lactose intolerance and cow’s milk allergy were the two main important drivers for the creation of plant-based probiotic beverages. The consumption of probiotics and synbiotics exert an advantageous effect on host gut microflora, and they are capable of treating diarrheal diseases. However, the development of such type of functional beverages or milk alternatives is very challenging owing to the wide variation in the composition of plant matrices and higher consumer expectations for palatability and well-being. Other technological challenges in the development of plant-based probiotics include maintaining the viability of the probiotic culture throughout the storage, preventing the generation of off-flavor and odor during the storage, and maintaining the textural stability. Fermentation, germination, roasting, and enzymatic treatments proved beneficial in improving the textural stability and flavor profile of the plant-based probiotic products. Legumes, cereals, seeds, and nuts are an important source of prebiotics and can offer newer approaches in the development of affordable probiotic functional beverages. Micro- and nanoencapsulation technologies expressed a potential in maintaining the viability of culture in probiotic formulations by creating a suitable biological carrier; however, further innovative technological interventions might represent an important solution for the stability and viability of probiotics in newer food matrices. Also, advanced food processing technologies such as high hydrostatic pressure, high-pressure homogenization, pulsed electric field processing, and ultrasonication offer suitable approaches for processing and preservation of probiotic beverages in replacement to thermal processing.
Article
Malnutrition is among the top 6 risk factors for death in India, and iron deficiency anemia (IDA) is regarded as one of the major contributors, with nationwide prevalence >60% among women. Nutritional anemia accounts for ∼70% anemia prevalence among Indian children and adolescents, specifically in females. Evidence suggests that current supplementation and fortification practices alone may make little difference in reducing the risk of IDA. Sustainable food-based strategies need to be determined. This review provides an overview of IDA in India and elaborates the food-based solutions. Factors that affect iron bioavailability have been discussed while exploring different plant-based food synergies to improve iron absorption. Nutritional and non-nutritional challenges have been highlighted. A case study has been incorporated that analyses Health Management Information System data for certain pregnancy outcomes among severely anemic pregnant women. It highlights the need for implementing alternative food-based strategies apart from the government programs. Iron-rich plant sources, with appropriate ratios of bioavailability enhancers and inhibitors can be utilized to develop effective products. However, this cannot be easily achieved. Obtaining higher concentrations of iron from food sources alone is challenging. Processing techniques may lower antinutrient content but risk mineral loss and vitamin degradation from the food matrix. Most studies focus on increasing iron content via fortification rather than enhancing its bioavailability. Safety, accessibility, and affordability issues of previous approaches need to be addressed. It is essential to understand the chemistry behind iron bio-accessibility and absorption to develop ready-to-eat plant-based food formulations, with highly bioavailable iron, which could be a plausible solution.
Chapter
Fermentation is recognized as a natural way to preserve and safeguard foods and beverages, enhance the nutritional value, improve the digestibility, destroy undesirable components, and inhibit undesirable microorganisms. The fermentation process and the resulting fermented products have recently attracted scientific interest as consumers are becoming aware of the possible positive role diet can play in disease risk management and perhaps because of their increasing interest in the relations between food and quality of life. In African civilizations, fermented cereal food still plays a major role in combating food spoilage and foodborne diseases that are prevalent in many of its resource disadvantaged regions. The value of fermented African cereal products cannot be overemphasized, as they have always played a vital role in diet and nutrition. The benefits associated with African cereal products, such as increased shelflife, palatability, and nutritional value, suggest the importance of these foods. The probiotic effects of various fermented African cereal foods and their associated microbial cultures look promising and warrant further research. Fermentation of African cereal products of probiotic LAB from traditional foods can be a suitable alternative source of antimicrobial agents, incorporated in the fight against emerging antibiotic-resistant microorganisms. Probiotic bacteria have a potential in solving current and emerging lifestyle diseases. The consumption of fermented African cereal foods is part of African culture and will continue to be so.
Article
In this study, the levels of Al, As, Ca, Co, Cr, Cu, Fe, K, Mg, Mn, Mo, Na, Ni, P, Pb, Sr and Zn were determined in 56 composite samples of food aids using inductively coupled plasma mass spectrometry (ICP-MS). It also looked at the potential of food aids on mineral provision for pregnant and lactating women (PLW). The mean mineral contents in cereals were 46.3-378 mg kg⁻¹ for Ca, 24.6-64.4 mg kg⁻¹ for Fe, 2752-4072 mg kg⁻¹ for K, 774-1510 mg kg⁻¹ for Mg, and 14.1-26.1 mg kg⁻¹ for Zn. Cereals presented low dietary significance for K, Ca and Zn as a daily portion (450 g) could only provide between 5 and 69% of Adequate Intake (AI) or Recommended Dietary Allowance (RDA) for PLW. Conversely, corn soya blend (CSB) and pulses appear to play a key role in mineral intakes. However, the existing daily ration for pulses demonstrated little importance to complement dietary K and Ca deficits. Fortunately, Target Hazard Quotient (THQ) values were low enough to guarantee no potential health risks associated with several toxic elements. Overall, it was observed that the food aids do not provide sufficient amount of selected minerals for PLW.
Article
A controlled in-vitro experiment was conducted to determine the bioaccessibility of extrinsic soil iron in pearl millet contaminated with typical Malawian soils. Pearl millet was contaminated with soils at ratios typically encountered in real life. Iron concentrations of soil-contaminated flour increased such that soil-derived iron contributed 56, 83 and 91% of the total iron when the proportions of soil were 0.1, 0.5 and 1% (soil: grain w/w), respectively. When soils were digested alone, the concentration of bioaccessible iron differed depending on the type of soil. However, the concentration of bioaccessible iron in soil-contaminated flours did not exceed that of uncontaminated flour and there was no effect of soil type. This suggests that knowledge of the proportion of extrinsic soil iron in soil-contaminated grains would be useful for iron bioavailability estimations. Vanadium is a reliable indicator of the presence of extrinsic soil iron in grains and has potential applications in this regard.
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Ben-kida and ben-saalga are popular pearl-millet-based fermented gruels in Burkina Faso. A survey of 318 households in Ouagadougou (Burkina Faso) showed that they are often used as complementary food for young children. Pearl millet and gruels, sampled in 48 production units, were analysed for proximate composition, factors reducing nutrient bioavailability (phytate, insoluble fibres and iron-binding phenolic compounds), alpha-galactosides, sugars, total lactic acid and d-lactic acid, zinc and iron contents. The effects of processing of pearl millet into fermented gruel are discussed. Both positive effects (e.g. a decrease in factors reducing nutrient bioavailability or alpha-galactosides) and undesirable effects (e.g. considerable lipid, protein, iron and zinc losses) were observed. Lactic acid was produced during processing and d(-)-lactate was detected in all samples. The gruels had very low energy density, even after addition of sugar, and low lipid, protein and mineral contents, well below recommendations for complementary foods.
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: To determine the impact of contaminant iron and geophagy on iron intake and status of persons living in developing countries. : Literature for review was identified by searching Medline and Agricola, from appropriate other texts and from three reports from the Opportunities for Micronutrient Interventions (OMNI) Project of USAID. : The dietary intake of iron by people living in developing countries is generally high but iron deficiency remains prevalent. This apparent paradox is because the iron being consumed is predominantly in the non-haem form, which is poorly absorbed. Some of this non-haem iron is from contamination of food with iron from soil, dust and water; iron leaching into food during storage and cooking; contamination during food processing such as milling; and the practice of geophagy. : Although the contribution of contaminant iron to overall iron intake is well documented, its absorption and thus its impact on iron status is not. To be available for absorption, contaminant iron must join the common non-haem pool, i.e. be exchangeable. The absorption of exchangeable contaminant iron is subject to the same interactions with other constituents in the diet as the non-haem iron that is intrinsic to food. The limited available evidence suggests wide variation in exchangeability. In situations where a significant fraction of the contaminating iron joins the pool, the impact on iron status could be substantial. Without a simple method for predicting exchangeability, the impact of contaminant iron on iron status in any particular situation is uncertain. : Interventions known to increase the absorption of iron intrinsic to foods will also increase absorption of any contaminant iron that has joined the common pool. Any positive effect of geophagy resulting from an increased intake of iron is highly unlikely, due to inhibiting constituents contained in soils and clays. The efficacy of approaches designed to increase the intake of contaminant iron remains encouraging but uncertain. An approach using multiple interventions will continue to be essential to reduce iron deficiency anaemia.
Article
The capacity of cetyl trimethylammonium bromide to dissolve proteins in acid solution has been utilized in development of a method, called acid-detergent fiber method (ADF), which is not only a fiber determination in itself but also the major preparatory step in the determination of lignin. The entire procedure for determining fiber and lignin is considerably more rapid than presently published methods. Compositional studies show ADF to consist chiefly of lignin and polysaccharides. Correlations with the new fiber method and digestibility of 18 forages (r = —0.79) showed it to be somewhat superior to crude fiber (r = —0.73) in estimating nutritive value. The correlation of the new lignin method and digestibility was -0.90 when grass and legume species were separated.
Article
The Centro Internacional de Mejoramiento de Maiz y Trigo ( CIMMYT) maize-breeding programme has been focusing on identifying white-grained maize germplasm that has the potential to increase kernel iron and zinc concentrations, especially in sub-Saharan Africa. In addition, research at Cornell University has focused on traits such as multiple aleurone layer, which can increase kernel iron and zinc concentrations, and low phytic acid concentration, which holds promise for improving the bioavailability of iron and zinc. More than 1,400 improved maize genotypes and 400 landraces were grown and evaluated to assess grain iron and zinc concentrations. These materials represented all white-grained landraces that belonged to the core collection of CIM-MYT's germplasm bank, all white- and yellow-grained CIMMYT maize germplasm pools and populations, all white-grained materials that are currently in the active breeding programme of CIMMYT-Zimbabwe, and 57 white-grained maize cultivars currently grown in southern Africa. After a very thorough evaluation of the genetic variability of iron and zinc potentially available in white-grained tropical maize germplasm, promising genetic variability was found in both improved maize germplasm and landraces. One difficulty that maize breeders encounter is that grain iron and zinc concentrations are often correlated negatively with grain yield, which may result from the increased carbohydrate content of high-yielding materials, so that a given amount of iron and zinc is diluted. The multiple aleurone trait may be a fast track to overcome this effect. This trait is being introgressed into various materials in both the United States and southern Africa.
Article
The presence of polyphenols and phytate in cereal products has been shown to interfere with the bioavailability of minerals such as iron. In the present study, we added enzymes (wheat phytase and mushroom polyphenol oxidase) during fermentation of tannin sorghum gruels prepared from flour with or without addition of 5% flour of germinated tannin-free sorghum grains (power flour), and investigated the effects on phenolic compounds, phytate and in vitro accessible iron. Assayable phenolic compounds were significantly reduced by fermentation, with high reductions observed in gruels with added enzymes. Fermentation of the gruels with addition of enzymes reduced (on average) total phenols by 57%, catechols by 59%, galloyls by 70% and resorcinols by 73%. The phytate content was significantly reduced by fermentation (39%), with an even greater effect after addition of power flour (72%). The largest reduction of phytate (88%) was, however, obtained after addition of phytase. The in vitro accessible iron was 1.0% in the sorghum flour and it increased after fermentation with power flour and/or with enzymes. The highest in vitro accessibility of iron (3.1%) was obtained when sorghum was fermented with addition of power flour and incubated with phytase and polyphenol oxidase after the fermentation process.
Article
Complementary foods based on cereals and legumes often contain high amounts of phytic acid, a potent inhibitor of mineral and trace element absorption. The possibility to degrade phytic acid during the production of complementary foods by using whole grain cereals as the phytase source was investigated. Whole grain rye, wheat, or buckwheat (10%) were added to cereal-legume-based complementary food mixtures, and phytic acid was shown to be completely degraded in a relatively short time (1.5 to 3 h) when incubated at optimal conditions for cereal phytase. The potential usefulness of the method for industrial production was demonstrated with a complementary food based on wheat and soybean.
Article
The degradation and leaching of phytates, phytase activity and iron and zinc concentrations have been studied after soaking of whole seeds, dehulled seeds and flours of millet and soybean, in order to investigate the efficiency of soaking on reducing Phy/Fe and Phy/Zn molar ratios. When using millet grains, dehulling and milling before soaking facilitated the leaching of phytates and phytases in the aqueous medium and hence phytate degradation. Dehulling of soybean seeds led to a marked increase in phytate content, whereas milling favoured reactions between phytases and phytates. The Phy/Fe and Phy/Zn molar ratios decreased only slightly during soaking. The highest decreases for millet were obtained after soaking of flour for 8 h (Phy/Fe: 10.8–7.7 and Phy/Zn: 20.3–15.1), and after soaking of whole seeds for 24 h for soybean (Phy/Fe: 10.4–9.4 and Phy/Zn: 23.8–19.1). Cooking of flours with water used for soaking did not increase phytate degradation.
Article
Food composition data are important for estimating energy and nutrient intakes. The objectives of this study were, first, to evaluate the proximate and inorganic composition of foods eaten in northern Benin and second, to estimate the potentially inhibiting effect of phytate on iron and zinc bioavailability. Chemical analyses were performed in 23 samples of most frequently consumed foodstuffs collected from retailers in local markets. Proximate composition was analysed by routine methods. Inorganic constituents and phytate were analysed using ICP-AES and HPLC. Protein contents were in agreement with those in FAO food composition database. Fat and fibre were in general higher whereas carbohydrate and energy were lower. Differences were mainly due to analytical or calculation methods. The most important sources of iron and zinc in children's diets were maize, sorghum and millet. In these cereals, iron and zinc ranged from 2.6 to 8.4 and 2.2 to 3.4 mg/100 g, respectively. Phytate ranged from 104 to 503 mg/100 g. Phytate/iron and phytate/zinc molar ratios ranged from 1 to 11 and 3 to 22, respectively. They suggest poor iron and zinc bioavailability. Reducing phytate and polyphenol contents in order to improve iron and zinc bioavailability from the most frequently consumed cereal food needs to be studied.
Article
Representative staple foods from Sidama, Southern Ethiopia, were analyzed for phytate using HPLC, and for Zn, Fe and Ca by flame atomic absorption spectrophotometry (AAS). Enset starchy foods had the lowest phytic acid content, followed by fermented injera prepared from tef. Oleaginous seeds (niger and sesame) had the highest phytate content (∼1600 mg/100 g). The iron content of raw tef and tef injera, unlike barley flour or corn bread, varied markedly, attributed to contaminant iron from soil. The foods prepared from enset and tef were also rich sources of calcium. Most of the fermented foods prepared from enset and tef had low Phy:Zn and Phy:Fe molar ratios, whereas corn bread (unleavened), kidney beans, sesame, and niger seeds had higher molar ratios. Absorption of intrinsic Zn, Fe, and Ca as well as any exchangeable contaminant iron is unlikely to be compromised by phytate in the fermented foods prepared from enset and tef, unless consumed together with high phytate foods such as corn bread, legumes, and oil seeds.
Article
The objective of this study was to investigate the influence of base systems used to regulate pH values of digests on iron dialysability as an indicator of bioavailable iron. We studied the pertinence of measuring titratable acidity to pH 7.5 with KOH to calculate mEq of NaHCO3 to be used for pancreatic digestion/dialysis. The pH achieved using the same mEq of each base was lower when using NaHCO3 than when using KOH. The discrepancy between achieved and attempted pH was uneven for several iron sources. Differences in pH regulation procedure, including type and concentration of base or buffer added to the pepsin digest rendered different final digest/dialysate pH values, thus affecting dialysable iron. A modification of in vitro equilibrium dialysis method is proposed using PIPES buffer of sufficient molarity to obtain a uniform final pH of 6.5 in digest/dialysate systems. The main factors taken into account to calculate buffer concentration were buffer capacity of food matrix (HCl mEq required to reach pH 2), HCl mEq included in the aliquot of pepsin suspension, acid or base mEq generated through enzymatic hydrolysis during in vitro digestion and intrinsic food pH (HCl mEq to adjust food matrix pH to 6.5). With these data buffer molarity for each food matrix can be calculated. Modifications suggested for the equilibrium dialysis method allowed development of a uniform final pH of the digest/dialysate system in a variety of foods assayed.
Article
The effects of cooking utensils on the total and bioavailable iron contents of five green leafy vegetables, along with related promoters and inhibitors, were investigated. The cooked and fresh greens were analysed for moisture, total and bioavailable iron, ascorbic acid, dietary fibre, tannins, total oxalates and soluble oxalates by standard techniques. Moisture content of fresh greens ranged from 80–90%, total dietary fibre (5–11 g/100 g), oxalates (0.022–1.37 g/100 g) and tannin (41–166 mg/100 g). Cooking in different utensils had no effect on these parameters. Ascorbic acid content ranged from 8.7 to 88.3 mg/100 g in fresh greens and was reduced by 18–64% on cooking. The total and ionisable iron contents of greens ranged from 3 to 13 mg/100 g and 0.43 to 2.7 mg/100 g, respectively, and increased on cooking in iron utensil to 9.7 to 17.5 mg/100 g and 1.50 to 8.56 mg/100 g, respectively. The availability of iron, in relation to total iron, of greens cooked in iron utensils was either comparable or marginally higher than those cooked in other metallic utensils. Since the total iron content of greens cooked in iron utensils was high, the actual amount of available iron also increased. It can be concluded that cooking in iron utensils increases the total as well as the available iron content of greens.
Article
The iron bioavailability of food cooked in an iron pot was studied. Iron deficiency was produced in 42 21-day old Wistar rats over a period of 5 weeks, while 18 rats receiving a complete diet throughout the experiment were used as a control group (CG). After the period of iron depletion, the animals were subdivided into 3 subgroups: one continued to receive the basal diet (BB), the second was fed a complete diet (BC), and the third received the basal diet cooked in an iron pot (BI). After 4 weeks, the BC and BI group did not differ significantly (p>0.05) from CG in hemoglobin, hematocrit, protoporphyrin, serum iron and transferrin saturation and that it promoted the correction of the parameters studied within four weeks.
Article
Iron differs from other minerals because iron balance in the human body is regulated by absorption only because there is no physiologic mechanism for excretion. On the basis of intake data and isotope studies, iron bioavailability has been estimated to be in the range of 14-18% for mixed diets and 5-12% for vegetarian diets in subjects with no iron stores, and these values have been used to generate dietary reference values for all population groups. Dietary factors that influence iron absorption, such as phytate, polyphenols, calcium, ascorbic acid, and muscle tissue, have been shown repeatedly to influence iron absorption in single-meal isotope studies, whereas in multimeal studies with a varied diet and multiple inhibitors and enhancers, the effect of single components has been, as expected, more modest. The importance of fortification iron and food additives such as erythorbic acid on iron bioavailability from a mixed diet needs clarification. The influence of vitamin A, carotenoids, and nondigestible carbohydrates on iron absorption and the nature of the "meat factor" remain unresolved. The iron status of the individual and other host factors, such as obesity, play a key role in iron bioavailability, and iron status generally has a greater effect than diet composition. It would therefore be timely to develop a range of iron bioavailability factors based not only on diet composition but also on subject characteristics, such as iron status and prevalence of obesity.
Article
The physical and chemical changes that occurred during a 72-h fermentation period were studied in two differently processed maize doughs from Bénin, referred to as home-produced and commercial mawè. The pH decreased from 6·1 to 3·5 in the commercial process and from 6·2 to 3·6 in the home-style process, whereas the titratable acidity increased from 0·2 to 1·7% (w/w, lactic acid) and from 0·3 to 2·3%, respectively. Home-produced mawè had significantly higher levels of crude fat, crude fibre and ash compared with the commercial mawè, as a consequence of the difference in the processing methods. No marked changes in proximate composition occurred during subsequent fermentation. Commercial mawè was whiter than home-produced mawè, and this whiteness increased with increasing fermentation time. Fermentation significantly increased the swelling and thickening capabilities of mawè, which were more pronounced in the commercial than in home-produced samples. Overall, the commercial mawè process appeared to be a technologically more advanced and effective method of mawè manufacture than the home process.
Article
Cereal fermentations in Africa and Asia involve mainly the processing of maize, rice, sorghum and the millets. Lactic acid bacteria (Lactobacillus, Pediococcus), Enterobacter spp., yeasts (Candida, Debaryomyces, Endomycopsis, Hansenula, Pichia, Saccharomyces and Trichosporon spp.) and filamentous fungi (Amylomyces, Aspergillus, Mucor, and Rhizopus spp.) contribute to desirable modifications of taste, flavour, acidity, digestibility, and texture in non-alcoholic beverages (e.g., uji, and ben-saalga), porridges (e.g., mawè) and cooked gels (e.g., kenkey, idli, and mifen). In addition, alcoholic beverages (beers such as tchoukoutou and jnard; and spirits e.g. jiu) are obtained using malt, or using amylolytic mixed microbial starter cultures as generators of fermentable substrates. Wet processing, marketing of multi-purpose intermediate products, co-fermentation for texture and nutrition, and mixed culture fermentations as practiced in indigenous fermentation processes are of interest for industrial innovation and for better control of natural mixed culture fermentation systems. On the other hand, the nutritional properties of traditional cereal fermented products can be enhanced by increasing their nutrient and energy density, as well as by increasing their mineral status by combining mineral fortification and dephytinization.
Article
Lactic acid bacteria responsible for the fermentation of a pearl-millet based fermented gruel, ben-saalga, were investigated for enzyme activity in relation with the nutritional characteristics of gruels used as complementary foods for young children. Thirty pre-selected LAB from a set of 155 isolates were characterized principally for their ability to produce amylase, phytase and alpha-galactosidase. Two Lactobacillus plantarum strains (4.4 and 6.1) and three Lactobacillus fermentum strains (11.11.2, 3.7, 7.4) able to produce one or more of these enzymes were selected. Only weak amylase activity was found in the two Lactobacillus plantarum strains. alpha-amylase activity was associated with cells and was lower than 0.05 Ceralpha Units/ml. Phytase activity was detected in all five strains and was linked to the cell. The highest phytase activity was found in Lb. plantarum 4.4 and 6.1 (348.7 +/- 17.4U/ml and 276.3 +/- 51.4U/ml, respectively) and Lb. fermentum 7.4. (276.3 +/- 13.2U/ml). All strains displayed a cell-linked alpha-galactosidase activity. In a medium containing 2% glucose, the highest cellular activity was found in Lb. fermentum 3.7 (1441.1 +/- 133.7U/ml) and Lb. plantarum 4.4 (1223.1 +/- 148.3U/ml) after 6h of fermentation in the presence of stachyose, and in Lb. plantarum 4.4 (763.3 +/- 23.5U/ml) and Lb. fermentum 7.4 (346.7 +/- 14.8U/ml) after 24h of fermentation with raffinose. These results are consistent with previous observations showing that phytates and alpha-galactooligosaccharides decreased during the natural lactic acid fermentation of pearl millet slurries, and that partial starch hydrolysis can be performed by endogenous microflora provided a pre-gelatinisation step is included in the process.
Article
With the aid of histo- and cytochemical examinations, and elemental x-ray analyses of maize, Zea mays L. var. Idahybrid 216, iron was found to be highly concentrated in the outer cell layers of the scutellum and in the aleurone layer. It is associated with roughly spherical structures identified as protein bodies. Analyses of the blackeyed pea, Vigna sinensis L., seeds indicate that iron is distributed throughout the cotyledon; however, the most intense concentration is at the periphery where the protein bodies are quite numerous. The histo- and cytochemical tests were made with the aid of the Prussian Blue reaction (acidified potassium ferrocyanide) and the Ferrozine reagent. The x-ray analyses were made with the aid of the elemental x-ray analysis method (EXAM) using a Model 707A energy dispersive x-ray analyzer(EDAX), and a scanning electron microscope (SEM).
Article
Iron absorption was measured from five kinds of bread made from various types of flour and fermented in different ways in order to obtain a wide variation in the content of fiber, phytate (inositol hexaphosphate) and its degradation products, inorganic phosphate and inositol phosphates with fewer numbers of phosphate groups (inositol pentaphosphate through monophosphate). Each experiment had 9-10 subjects and, in each subject, iron absorption was measured from control rolls made from low extraction wheat flour and one kind of test roll using two different radioiron tracers: 55Fe and 59Fe. The inhibition of iron absorption was closely related to the content of phytate-phosphorous as determined using the AOAC method, and to the sum of the tri- through hexaphosphate groups as determined using the HPLC method. As an example, prolonged fermentation of whole-rye bread reduced total inositol phosphates to the same amount as in the control rolls and increased fractional iron absorption to the same high level, in spite of a fiber content five times as great. The results strongly suggest that the inhibitory effect of bran on iron absorption is due to its content of phytate and other inositol phosphates present after fermentation, rather than to its content of fiber or other constituents. Thus, effective fermentation will increase the bioavailability of iron in whole-meal bread.
Article
An in vitro method for estimating food iron availability is described. The method involves simulated gastrointestinal digestion followed by measurement of soluble, low molecular weight iron. Mixtures of foods (meals) were homogenized and exposed to pepsin at pH 2. Dialysis was used to adjust the pH to intestinal levels and digestion was continued after the addition of pancreatin and bile salts. Iron from the digestion mixture which diffused across a 6 to 8000 molecular weight cutoff semipermeable membrane was used as an indicator of available iron. Results were similar when intrinsic food iron or added extrinsic radioiron was measured. Availability estimates were made on meals formulated to contain known iron availability enhancing and inhibiting factors. Relative availabilities determined for a series of meals containing ascorbic acid, eggs, orange juice, tea, coffee, cola, or whole wheat bread show that the method accurately reflects actual food iron availability.
Article
A method is described to measure in vitro the extent of isotopic exchange between the native nonheme food iron and added inorganic reduction to radioiron tracer. The food is digested with pepsin and trypsin in the presence of radioiron. The exchangeability of food iron is calculated from the specific activity in the food and in an extract of bathophenantroline in isoamyl alcohol obtained after digesting this food. The precision and accuracy of the method is illustrated by two kinds of studies, those in which different amounts of contamination iron are added to a meal and those evaluating contamination iron in natural meals. The present method will make it possible to measure validly iron absorption from meals contaminated with unknown amounts of iron of unknown exchangeability with the extrinsic radioiron tracer.
Article
In less-developed countries, novel strategies are needed to control iron-deficiency anaemia, the most common form of malnutrition. We undertook a community-based randomised controlled trial to assess the effects of iron or aluminium cooking pots in young Ethiopian children. Analysis was by intention-to-treat. The primary outcomes were change in children's haemoglobin concentration, weight, or length over the study period. We also did a laboratory study of total and available iron in traditional Ethiopian foods cooked in iron, aluminium, and clay pots. 407 children, one per household, entered the study. The change in haemoglobin concentration was greater in the iron-pot group than in the aluminium-pot group (mean change to 12 months 1.7 [SD 1.5] vs 0.4 [1.0] g/dL; mean difference between groups 1.3 g/dL [95% Cl 1.1-1.6]). The mean differences between the groups in weight and length gain to 12 months (adjusted for baseline weight or length) were 0.6 cm (95% CI 0.1-1.0) and 0.1 kg (-0.1 to 0.3). The laboratory study showed that total and available iron was greatest in foods cooked in iron pots, except for available iron in legumes for which there was no difference between types of pot. Ethiopian children fed food from iron pots had lower rates of anaemia and better growth than children whose food was cooked in aluminium pots. Provision of iron cooking pots for households in less-developed countries may be a useful method to prevent iron-deficiency anaemia.
Article
Marginal zinc deficiency and suboptimal zinc status have been recognized in many groups of the population in both less developed and industrialized countries. Although the cause in some cases may be inadequate dietary intake of zinc, inhibitors of zinc absorption are most likely the most common causative factor. Phytate, which is present in staple foods like cereals, corn and rice, has a strong negative effect on zinc absorption from composite meals. Inositol hexaphosphates and pentaphosphates are the phytate forms that exert these negative effects, whereas the lower phosphates have no or little effect on zinc absorption. The removal or reduction of phytate by enzyme (phytase) treatment, precipitation methods, germination, fermentation or plant breeding/genetic engineering markedly improves zinc absorption. Iron can have a negative effect on zinc absorption, if given together in a supplement, whereas no effect is observed when the same amounts are present in a meal as fortificants. Cadmium, which is increasing in the environment, also inhibits zinc absorption. The amount of protein in a meal has a positive effect on zinc absorption, but individual proteins may act differently; e.g., casein has a modest inhibitory effect of zinc absorption compared with other protein sources. Amino acids, such as histidine and methionine, and other low-molecular-weight ions, such as EDTA and organic acids (e.g., citrate), are known to have a positive effect on zinc absorption and have been used for zinc supplements. Knowledge about dietary factors that inhibit zinc absorption and about ways to overcome or remove these factors is essential when designing strategies to improve the zinc nutrition of vulnerable groups.
Article
Insoluble dietary fiber is a known inhibitor of mineral absorption, whereas the effects of soluble dietary fibers (including prebiotics) are less known. The aim was to study calcium, iron, and zinc availabilities from dairy infant formulas supplemented with soluble dietary fibers and modified starches in vitro. Dairy infant formulas were supplemented with soluble dietary fibers (3%, dry wt) and modified starches (16% pregelatinized rice starch and 1.9% maltodextrin, dry wt) and kept in a well-controlled and defined environment in vitro. Pooled mature human milk was used as the reference standard. Calcium availability from standard formula was elevated by 30% after inulin supplementation (17.2%), whereas locust bean gum (11.9%) and high esterified pectin (11.7%) reduced availability by approximately 10%. Iron availability from standard formula was increased by pregelatinized rice starch (3.8%), whereas availability was reduced in the following order: high esterified pectin (2.3%), oligofructose (2.2%), and low esterified pectin (2.1%). Zinc availability was highest after the addition of pregelatinized rice starch (13.5%) but lowest with the addition of locust bean gum (6.8%) and maltodextrin (5.4%). This study showed that addition of soluble dietary fiber affects calcium, iron, and zinc availabilities in positive (inulin) and negative ways, depending on the type of the dietary fiber used.
Article
To complete a systematic review of the effect of preparing food cooked in iron pots on haemoglobin concentrations and to assess compliance with pot use. DESIGN AND SEARCH STRATEGY: We searched The Cochrane Database of Systematic Reviews, Database of Abstracts of Reviews of Effectiveness, The Cochrane Controlled trials Register, The Cochrane Methodology Register, Health Technology Assessment Database and NHS Economic Evaluation Database (Cochrane Library, Issue 3, 2002). Medline (1966 to May 2002) and EMBASE (1988 to May 2002). Reference lists of published trials were examined for other potentially relevant trials and authors of selected trials were contacted to obtain information about ongoing or unpublished trials. Selection criteria included randomized trials which compared the effect of food cooked in cast iron pots with food cooked in noncast iron pots on participants of a minimum age of 4 months. One reviewer applied inclusion criteria to potentially relevant trials. Two reviewers assessed trial quality and extracted data. Three trials were eligible for inclusion in the review. There is some evidence from these studies that eating food prepared in iron pots increases the haemoglobin concentration of anaemic/iron deficient individuals. This effect seems to be modified by compliance, users age, and the presence of malaria and hookworm. Compliance with pot use varies considerably between countries depending on several factors, including: size of the cooking pot, targeted user group, whether the pot is used as an extra or replacement pot, and familiarity with cast iron pots. The introduction of iron pots or improving their use in communities in developing countries for the preparation of food maybe a promising innovative intervention for reducing iron deficiency and iron deficiency anaemia. Further research is required to monitor the use and effectiveness of this intervention.
Article
Phytic acid is a potent inhibitor of native and fortification iron absorption and low absorption of iron from cereal- and/or legume-based complementary foods is a major factor in the etiology of iron deficiency in infants. Dephytinization of complementary foods or soy-based infant formulas is technically possible but, as phytic acid is strongly inhibitory at low concentrations, complete enzymatic degradation is recommended. If this is not possible, the phytic acid to iron molar ratio should be decreased to below 1:1 and preferably below 0.4:1. Complete dephytinization of cereal- and legume-based complementary foods has been shown to increase the percentage of iron absorption by as much as 12-fold (0.99% to 11.54%) in a single-meal study when the foods were reconstituted with water. The addition of milk, however, inhibits iron absorption and overcomes the enhancing effect of phytic acid degradation. Dephytinization can therefore be strongly recommended only for cereal/legume mixtures reconstituted with water, especially low-cost complementary foods destined for infants in developing countries. In countries where infant cereals are consumed with milk, ascorbic acid addition can more easily be used to overcome the negative effect of phytic acid on iron absorption. Similarly with soy-based infant formulas, especially if manufactured from low-phytate isolates, ascorbic acid can be used to ensure adequate iron absorption.
Article
The first cases of human Zn deficiency were described in the 1960s in the Middle East. Nevertheless, it was not until 2002 that Zn deficiency was included as a major risk factor in the global burden of disease, and only in 2004 did WHO/UNICEF include Zn supplements in the treatment of acute diarrhoea. Despite this recognition Zn is still not included in the UN micronutrient priority list, an omission that will continue to hinder efforts to reduce child and maternal mortality, combat HIV/AIDS, malaria and other diseases and achieve the UN Millennium Development Goals for improved nutrition in developing countries. Reasons for this omission include a lack of awareness of the importance of Zn in human nutrition, paucity of Zn and phytate food composition values and difficulties in identifying Zn deficiency. Major factors associated with the aetiology of Zn deficiency include dietary inadequacies, disease states inducing excessive losses or impairing utilization and physiological states increasing Zn requirements. To categorize countries according to likely risk of Zn deficiency the International Zinc Nutrition Consultative Group has developed indirect indicators based on the adequacy of Zn in the national food supplies and/or prevalence of childhood growth stunting. For countries identified as at risk confirmation is required through direct measurements of dietary Zn intake and/or serum Zn in a representative sample. Finally, in at risk countries either national or targeted Zn interventions such as supplementation, fortification, dietary diversification or modification, or biofortification should be implemented, where appropriate, by incorporating them into pre-existing micronutrient intervention programmes.
Article
Maize is one of the most important cereal crops for human consumption, yet it is of concern due to its low iron bioavailability. The objective of this study was to determine the effects of processing on iron bioavailability in common maize products and elucidate better processing techniques for enhancing iron bioavailability. Maize products were processed to represent different processing techniques: heating (porridge), fermentation (ogi), nixtamalization (tortillas), and decortication (arepas). Iron and phytate contents were evaluated. Iron bioavailability was assessed using the Caco-2 cell model. Phytate content of maize products was significantly reduced by decortication (25.6%, p = 0.003) and nixtamalization (15%, p = 0.03), and iron content was reduced by decortication (29.1%, p = 0.002). The relative bioavailability (RBA, compared to 100% bioavailability of porridge with FeSO4) of ogi was significantly higher than that of other products when fortified with FeSO4 (p < 0.001) or reduced iron (p < 0.001). Addition of lactic acid (6 mg/g of maize) significantly increased iron solubility and increased bioavailability by about 2-fold (p < 0.01), especially in tortillas. The consumer panel results showed that lactic acid addition does not significantly affect the organoleptic characteristics of tortillas and arepas (p = 0.166 and 0.831, respectively). The results suggest that fermentation, or the addition of small amounts of lactic acid to unfermented maize products, may significantly improve iron bioavailability. Lactic acid addition may be more feasible than the addition of highly bioavailable but expensive fortificants. This approach may be a novel means to increase the iron bioavailability of maize products to reduce the incidence of iron deficiency anemia.
Article
Iron deficiency is one of the leading risk factors for disability and death worldwide, affecting an estimated 2 billion people. Nutritional iron deficiency arises when physiological requirements cannot be met by iron absorption from diet. Dietary iron bioavailability is low in populations consuming monotonous plant-based diets. The high prevalence of iron deficiency in the developing world has substantial health and economic costs, including poor pregnancy outcome, impaired school performance, and decreased productivity. Recent studies have reported how the body regulates iron absorption and metabolism in response to changing iron status by upregulation or downregulation of key intestinal and hepatic proteins. Targeted iron supplementation, iron fortification of foods, or both, can control iron deficiency in populations. Although technical challenges limit the amount of bioavailable iron compounds that can be used in food fortification, studies show that iron fortification can be an effective strategy against nutritional iron deficiency. Specific laboratory measures of iron status should be used to assess the need for fortification and to monitor these interventions. Selective plant breeding and genetic engineering are promising new approaches to improve dietary iron nutritional quality.
Article
An update on in vitro methods employed to assess iron bioavailability is presented. Solubility and dialyzability are not useful predictors of iron absorption, whereas Caco-2 cell models provide useful comparisons on the availability of iron from different sources. Strengths and weaknesses of in vitro approaches are briefly described, including the need to characterize Caco-2 cells in order to interpret results correctly. Further developments are required to refine Caco-2 model systems, including optimization and standardization of methods.