Trace element bioavailability as exemplified by iron and zinc

Plant foods can be improved as sources of essential micronutrients either by increasing the concentrations of nutrients in the food, increasing the bioavailability of micronutrients in the food, or both of these. Quantities of minerals in edible portions of crops are influenced by numerous complex, dynamic and interacting factors, including plant genotype, soil properties, environmental conditions and nutrient interactions. Similarly, numerous dietary and host factors interact to affect the bioavailability to animals and people of mineral nutrients in plant foods. Micronutrient bioavailability apparently can be improved by either increasing the quantity of substances within plant foods that enhance the absorption and utilization of micronutrients or by decreasing the quantity of dietary antinutrients that inhibit micronutrient absorption; however, processes that control and regulate the bioavailability of trace elements in plant foods consumed in mixed diets are not fully understood. Use of either stable or radioactive isotopes incorporated intrinsically into edible portions of plant foods during plant growth will likely provide the most reliable estimates of the bioavailability of micronutrients consumed in mixed diets. Increasing the dietary supply of staple plant foods rich in trace elements combined with increased knowledge of micronutrient bioavailability from these foods will meaningfully improve the nutritional health and well being of people.     

A preliminary study on the use of tempe-based formula as a weaning diet in Nigeria

Tempe, an Indonesian mold fermented food, was prepared from cowpeasand soybeans using the traditional oriental process with modifications whereappropriate. Four complementary foods were developed from whole maizemeal or dehydrated fermented maize (ogi) flour fortified with eithercowpea tempe or soybean tempe. Wholesomeness and potentials of thevanilla-flavored foods as weaning diets were determined. The nutrientcontent of all the developed products were within the range prescribed bythe FAO/WHO pattern for processed weaning foods. The products hadloose bulk densities between 0.40–0.55 g/ml and packed bulk densitiesbetween 0.68–0.75 g/ml; reconstitution indexes were between92.30–104.00 g/ml; viscosities were 34.2–65.0 CP at 70 ^°C and45.0–76.9 CP at 30 ^°C. Total plate counts ranged from 3.2 ×10³ – 4.3 × 10⁴cfu/g; coliforms staphylococcus, mold, andyeast were absent in some of the products. The results on sensoryattributes showed that tempe-based weaning diets were comparable withMameal, a commercial product. Maize and maize-fortified diets wereslightly higher in packed bulk density. Fortification reduced the viscosityof the diets and the values reduced with increasing temperature. Tempe-based weaning foods reconstituted easily in hot water, while cookingdestroyed most of the microorganisms present. Maize-based tempefortified foods were relatively inexpensive and have potential as weaningfoods.     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

小麦籽粒微量元素含量的研究进展

以禾谷类作物为主食引起的人体摄取必需微量元素(特别是Fe和Zn)不足,已对现代社会和谐发展造成沉重的经济负担和安全隐患。小麦(Triticum aestivumL.)是中国和全球大多数人主要的食物和矿质元素来源。小麦籽粒中Zn、Fe含量普遍较低,已引起国内外学者们的高度关注。本文综述了小麦籽粒微量元素含量器官间、基因型间的差异及其影响因素和相关性状研究进展,介绍了小麦籽粒吸收和富集微量元素的生理与遗传基础,展望了提高小麦籽粒微量元素的研究内容和方向。     

不同木薯种质资源主要矿物质元素差异性分析

为了解不同木薯种质资源矿物质元素含量,优选含量丰富的品种,为木薯的综合利用提供数据支撑,本文采用马弗炉法、原子吸收和原子荧光法分别对113份木薯种质资源灰分与矿物质元素含量进行测定,结果表明：矿物质元素Cr、Cu、Se含量均低于1 mg/kg（干重）,Ca、Fe、K、Mg、Mn、Na、Zn含量分别为66.39~1609.81 mg/kg、4.35~ 38.93 mg/kg、1954.56~8762.78 mg/kg、149.04~1143.73 mg/kg、4.48~37.40 mg/kg、36.80~530.40 mg/kg、6.35~24.83 mg/kg。利用概率分级法将113份木薯种质资源灰分及矿物质元素含量分为5级,即极高、高、中、低和极低,并推荐极高品系作为基础亲本材料。在相关性分析中,灰分与Fe、Mg、Na、Zn含量具有较为显著的相关性,Ca含量与K、Mn含量呈极显著正相关,Ca含量与Mg、Na含量呈极显著负相关,Fe含量与Mg、Na、Zn含量成极显著正相关,K含量与Mn含量呈极显著正相关,与Na含量呈极显著负相关,Mg含量与Na、Zn含量呈极显著正相关,Zn含量与Mn、Na含量呈极显著正相关。Zn与各矿物质元素的吸收有较强的相互促进作用,Fe含量与Mg、Na含量有较强的相互促进作用,Ca含量与K、Mn的吸收有较强的促进作用,而Ca、K、Mn与Fe、Mg、Na的吸收可能存在一定的拮抗作用。结合主成分分析、聚类分析对不同木薯种质资源矿物质元素含量进行综合评价,得到特征值大于1的主成分2个,累计方差贡献率达61.707%。聚类分析可将113个木薯种质资源分为3类,根据矿物质元素含量差异可将不同木薯品种分为Na、Mg、Zn、Fe含量较高和Mn、Ca、K、Zn含量较高两大类,主成分综合评价中‘274'‘50'‘571'‘521'‘417'等木薯种质资源得分较高。     

Effects of Nitrogen Fertilization and Genotype on Rice Grain Macronutrients and Micronutrients

High nitrogen(N)input features China’s intensive rice production system.To elucidate N and genotype effects on accumulation of macronutrients and micronutrients in grains of japonica rice,and to discuss its significance in rice production,a three-year field experiment involving six japonica rice varieties and seven N treatments were performed.Macronutrients(Ca,Mg,K,and Na)and micronutrients(Cu,Fe,Mn,and Zn)concentrations in brown and milled rice were measured using an atomic absorption spectrophotometer.For macronutrients,no consistently significant effect of N was detected in both brown and milled rice.For micronutrients,N showed significant effect,especially in lowering Zn accumulation in brown and milled rice.In addition,N tended to increase Fe concentration in milled rice.Genotype showed larger effect on distribution of minerals in milled rice than N.The high-yielding variety,Wuyunjing 7,accumulated larger proportion of Mg,K,and Zn in the milled rice as compared with the other five varieties,and could be of value for rice breeding programs aiming at high nutritional quality.The results demonstrated differences in response to N between macronutrients and micronutrients,and are of significance for coping with‘hidden hunger’both in humans and crops through agronomical practices.     

Mineral characteristics of leaves of plants from different phylogeny grown in various soil types in the temperate region

The objective of this research was to analyze selected minerals in leavesof plants, belonging to 166 species growing in alluvial, low pH, brownforest and serpentine soils. Mineral characteristics of the soils involved werealso determined.For the macronutrients, in trees grown in alluvial soil, N, P, Ca, and Mgconcentrations of leaves were higher in recently evolved plants than inplants with a longer period of evolution; K concentration remained constantregardless of evolution. In grasses grown in alluvial soil, it was difficult todetect the general tendency of mineral concentration. N, P, and Kconcentrations in alluvial soil were closely related to those in low pH andserpentine soils. Ca concentration in alluvial soil was lower than that in lowpH and serpentine soils. Mg concentration in alluvial soils was higher thanthat in low pH soils, while lower than that in serpentine soil. Therefore, N,P, and K accumulated according to the plant characteristics for theseelements, while Ca and Mg accumulation was strongly affected by the soilproperties.For the micronutrients, in trees, Fe and Mn remained constant regardlessof evolution; Zn concentration was lower in recently-evolved plants than inplants with a longer period of evolution. In grasses, Fe, Mn, and Znconcentrations in Caryophyllids were high. Except for Caryophyllids, Fe andCu concentrations remained constant, Mn concentration decreased withevolution, Zn concentration was higher in recently-evolved plants than inplants with a longer period of evolution.     

Mineral and trace element composition in induced mutants of pigeonpea (Cajanus cajan (L.) millsp.)

In the present investigation several mutants isolated during mutagenic studies of pigeonpea were analysed for Ca, Mg, Fe, Zn, Cu, Mn, Cr, Ni. The results have revealed changes in the concentrations of macro and micro mineral elements in the mutant seed material. These changes in concentrations are attributed to the altered genetic structure; due to mutations, the plant system might have absorbed and stored more or less amounts of the elements in the seeds.     

Mineral and protein content,test weight,and yield variations of hard red spring wheat grain as influenced by fertilization and cultivar

Among the complex factors affecting grain nutritional quality, protein and mineral content are highly important. A two-year study was conducted in eastern North Dakota to determine the influence of fertility on the protein and mineral content, test weight, and yield of two hard red spring wheat (Triticum aestivum L.) cultivars. Zero, medium (56, 12, and 47 kg/ha), and high (280, 122, and 465 kg/ha) rates of N, P, and K, respectively, were applied in a complete factorial arrangement to ‘Era’ (a semi-dwarf) and ‘Waldron’ wheat (a tall type) in 1977. Seven of these treatments were repeated in 1978. Micronutrients and S were also applied to most treatments in 1977, and micronutrients but no S to all treatments in 1978. In 1977 on a site with high residual NO₃-N, additions of N reduced yields and test weight but increased protein, P, Ca, Zn, Mn, and Fe content. At this site application of P increased grain yield, P, K, and Mg contents but reduced protein and Zn; fertilizer K increased Mn and Fe content and reduced yield, P, K, and Mg. In 1978, N additions increased grain yield, protein, Ca, and Fe but reduced Zn. The application of P and K had little influence on the composition of the grain in 1978. The two cultivars acted the same both years, with Waldron exceeding Era grain in protein (15%), P (12%), Mg (12%), Mg (12%), Zn (17%), Mn (30%), and Fe (12%). Era surpassed Waldron in test weight (2%), K (2%), and Ca (27%). Era proved to be more responsive to fertilizer additions for most grain parameters. Drier weather conditions and lower soil N status for the 1978 experiment produced grain higher in test weight and P, K, Ca, Mg, and Fe content but lower in yield, protein, and Zn. Many highly significant fertilizer-grain and grain-grain interactions were observed. Since wheat grain composition may often be altered by fertilizers and cultivars, the range of these changes should become known through investigations by soil scientists, agronomists, and nutritionists; additional research should be conducted to determine if their changes are of nutritional significance.     

粳稻“龙锦1号/香软米1578” F3家系群糙米矿质元素含量变异及相关性分析

 利用粳稻品种间杂交组合“龙锦1号/香软米1578”的196份F3家系,对糙米中Fe、Se、Zn、Cu、Mn、Ca、Mg、K、Na和P等10种矿质元素含量的变异及其相关性进行了分析。 10种矿质元素在F3家系间均有较大的变异,其中Na含量变异最大,Zn含量变异最小,变异系数分别为77.69％和12.04％。各矿质元素含量的变异系数大小顺序为Na>Se>Cu>Fe>Mg>Mn>Ca>P>K>Zn。不同矿质元素含量也有较大的差异,F3家系群各矿质元素含量平均值高低排序为P>K>Mg>Ca>Fe>Mn>Zn>Na>Cu>Se。糙米中10种矿质元素含量在F3家系群中均表现为正态分布,为由多基因控制的数量性状。Zn与Fe、Cu,Mn与Mg、Ca、K、P,Ca与Mg、K、Na、P,Mg与K、P,P与K、Na含量呈显著或极显著正相关,而Fe与Se、Mn与Na、Mg与Na含量呈显著或极显著负相关。Mn、Ca、Mg、K、P含量与其他矿质元素含量间的相关关系较Fe、Se、Cu、Zn含量与其他矿质元素含量间的相关关系更为密切。     

Effects of Soy Protein and Calcium Levels on Mineral Bioaccessibility and Protein Digestibility from Enteral Formulas

Enteral formulas (EF) are complex food systems which have all the nutrients in their matrix for the complete human nourishment. However, there are components in EF which can interact with minerals, reducing their absorption, and thereof the EF nutritional quality. The effect of soy protein (SP) and Ca content on Fe, Zn, and Ca bioaccessibility and protein digestibility (%DP) was assessed using a response surface design in EF. Tested SP levels were 2.5–5.0 g/100 mL of total protein. Ca levels were adjusted with Ca citrate within a range between 50 and 100 mg/100 mL. SP content negatively influenced %DP and Fe, Zn and Ca bioaccessibility. As SP content increased, mineral bioaccessibility and %DP decreased, probably due to the increased levels of phytic acid and trypsin inhibitors from SP. Ca content only affected %DCa, which had a direct relationship with Ca levels, while did not affect Fe and Zn bioaccessibility or %DP. Since Ca citrate did not impair Fe and Zn bioaccessibility, it could be an appropriate Ca source for EF fortification.     

Mineral bioaccessibility in French breads fortified with different forms iron and its effects on rheological and technological parameters

The present study investigated the effect of different forms of Fe used in the fortification of wheat flour on the rheological characteristics of flour and technological quality of French breads and the bioaccessibility of added Fe, Zn and Ca naturally occurring by in vitro assay. The results demonstrated that the wheat flour was suitable for use in bakery products; however, the farinograph and extensograph parameters were affected by different forms of Fe, which also changed the technological quality of breads, with no negative impacts on bread making. The NaFeEDTA and SF microencapsulated proved to be the most effective’s forms of iron, due to its higher dialyzed Fe content. Zinc bioaccessibility is not high, thus the NaFeEDTA contributed positively for the absorption of this mineral. In contrast, a high bioaccessibility of calcium was observed, which was not affected by the majority forms of iron. Additionally, Fe, Ca and Zn naturally occurring also presented high bioacessibility. Thus, French bread made with flour fortified with iron can contribute to demand and supply of minerals, and the form of Fe used can affect not only Fe bioaccessibility, but also Zn, leading to changes in the rheological properties of wheat flour and technological quality.     

Micronutrient bioavailability techniques: Accuracy,problems and limitations

Within the scientific agricultural community it is widely known that the total micronutrient content of soils is not a useful measure of the amount of `available' micronutrients to plants. Thus, soil tests have been developed to determine the amounts of micronutrients in soils available to plants for growth. This same concept applies to plant foods eaten by humans because not all of the micronutrients in plant foods are available (i.e. bioavailable) for absorption and or utilization. Antinutrients and promoter substances within plant foods that can either inhibit or enhance the absorption and/or utilization of micronutrients when eaten. As a result, numerous techniques have been developed to determine the amounts of bioavailable micronutrients present in plant foods when consumed in mixed diets with other dietary constituents that can interact and affect the micronutrient bioavailability. Unfortunately, micronutrient bioavailability to humans fed mixed diets is still a confusing and complex issue for the human nutrition community. Our understanding of the processes that control micronutrient bioavailability from mixed diets containing plant foods is relatively limited and still evolving. It remains the subject of extensive research in many human nutrition laboratories globally. This article reviews some of the numerous methodologies that have arisen to account for the bioavailability of micronutrients in plant foods when eaten by humans.     

Genetic diversity for grain nutrients contents in a core collection of finger millet (Eleusine coracana (L.) Gaertn.) germplasm

Finger millet is a promising source of micronutrients and protein besides energy and can contribute to the alleviation of iron (Fe), zinc (Zn) and protein malnutrition affecting women and preschool children in African and south-east Asian countries. The most cost effective approach for mitigating micronutrient and protein malnutrition is to introduce staple crop cultivars selected and/or bred for Fe, Zn and protein dense grain. Breeding finger millet for enhanced grain nutrients is still in its infancy. Analysis, detection and exploitation of the existing variability among the germplasm accessions are the initial steps in breeding micronutrient and protein-dense finger millet cultivars. Evaluation of finger millet core collection for grain nutrients and agronomic traits revealed a substantial genetic variability for grain Fe, Zn, calcium (Ca) and protein contents. The accessions rich in nutrient contents were identified and their agronomic diversity assessed. The accessions rich in Zn content have significantly higher grain yield potential than those rich in Fe and protein content. Grain nutrient-specific accessions and those contrasting for nutrient contents were identified for use in the strategic research and cultivar development in finger millet.     

Macro‐ and micromineral content of wrapped forages for horses

A study of macro‐ and micromineral contents in wrapped forages from farms in Sweden and Norway was conducted. Haylage samples were collected from 124 farms and analysed for contents of Ca, P, Mg, K, Na, Co, Cu, I, Fe, Mn, Se and Zn. Information on forage production was collected from each farm. Mean concentrations (standard deviations) of the samples were as follows: Ca, 5·3 (3·41); P, 2·7 (0·80); Mg, 1·8 (0·76); K, 21·8 (7·44); Na, 0·3 (0·61) g kg^?1 dry matter (DM); and Co, 0·09 (0·150); Cu, 4·9 (1·61); I, 0·25 (0·461); Fe, 194 (288·9); Mn, 85 (49·3); Se, 0·03 (0·054); and Zn, 23 (9·5) mg kg^?1 DM. Comparisons with mineral requirements of horses indicated that for Ca, Mg, K, Fe and Mn, the mean values were sufficient for maintenance requirements, but for P, Na, Co, Cu, Zn, I and Se, mean values were insufficient. For horses with requirements higher than maintenance, average contents of all minerals except Fe and Mn were insufficient. There were moderate to weak negative correlation coefficients between contents of neutral detergent fibre and Ca, P, Mg, Cu and Se. Forage harvested at late plant maturity may contain lower concentrations of these minerals.     

Quality Evaluation of Honey Harvested From Selected Areas in Tanzania With Special Emphasis on Hydroxymethyl Furfural (HMF) Levels

The physicochemical properties of honey harvested from popular honey-producing areas in Tanzania were investigated. Honey from Shibe-Dodoma had the highest values of specific gravity, total acidity, free fatty acid content, diastatic number, overall acceptability, and lowest hydroxymethyl-furfural (HMF) level as compared to honey samples from other areas. There was no significant difference (p>0.05) in terms of HMF in the other honey samples from Tanga, Morogoro, Same, Arusha, and Tabora. HMF levels in all honey samples were far below the maximum acceptable level of 40 mg/kg as recommended by the Codex Alimentarius Commission Standards before storage for 6 months. No traces of streptomycin and phenol were detected in all honey samples. It was concluded that according to the values of the studied quality parameters, the types of Tanzanian honey obtained from the popular honey producing areas may be judged to be of high quality.     

不同施氮水平对金菠萝苗期生长及养分吸收的影响

氮素是影响植物生长和养分吸收的重要养分之一,为深入理解菠萝氮素营养生理,本研究以金菠萝为试验对象,通过盆栽试验研究不同施氮水平（0、25、50、100、150、300 mg/kg）对金菠萝苗期植株生长、叶绿素和类胡萝卜素含量以及养分吸收的影响。结果表明：随施氮水平增加,金菠萝植株的叶片数、地上部干重、根系干重和总干重都持续增加,在300 mg/kg时生长最好;D叶中叶绿素a、b和类胡萝卜素含量随施氮水平升高呈先升后降的趋势,在100 mg/kg时达到最大值;施氮水平增加提高了金菠萝植株N、P、K的吸收;随施氮水平升高,茎、叶中Ca、Mg、Mn、Cu、Zn含量上升,但茎、根中Fe含量下降,除Fe以外的中微量元素吸收量呈增加趋势。因此,本试验条件下,施氮水平增加促进了金菠萝苗期生长与养分吸收。     

The influence of potassium fertilizer application on tuber yield and mineral element content of potato petioles during the growing season

Potassium was applied at rates equivalent to 0, 135, and 250 pounds per acre (0, 151, 180 kg K/ha) to study the effect of soil applied K on tuber yields and concentration of mineral elements in the petioles of potato plants during growth both measured at 14 day intervals. Petioles were analyzed for N, P, K, Ca, Fe, Mg, Zn, Cu, Al, Mn, and B. Seasonal trends in petiolar K content were highly correlated with tuber bulking regardless of rate of K application. Increasing K application rates generally increased petiolar levels of K and Zn (early in the season) and decreased the levels of N, Mg, Ca, Zn (late in the season), Al, Fe, Cu, and B in the petioles. Concentrations of P and Mn were unaffected by K applications. Seasonal trends in the mineral element content of petioles were not influenced by K. Results indicate that a prediction model for tuber yield based upon trends in the K content of petioles is valid under differing soil levels of K.     

应用诊断施肥综合法(DRIS)对槟榔叶片进行营养诊断

应用诊断施肥综合法(DRIS)对低产园和高产园槟榔进行了叶片营养诊断。结果表明,相对于高产园,低产园元素间关系较不平衡。槟榔叶片N、P、K、Ca、Mg以及Fe、Mn、Cu、Zn的适宜含量分别为(20.53±0.67)、(1.90±0.01)、(13.30±0.46)、(7.14±0.57)、(3.68±0.41)g/kg及(109.50±4.16)、(112.50±9.02)、(6.07±0.64)、(31.23±0.15)mg/kg。低产园N、P、K、Ca、Mg、Fe、Mn、Cu、Zn元素DRIS诊断指数分别为-44.58、-1.60、-17.16、0.09、-31.94、52.78、31.03、23.12、-11.74,需求强度较大的元素为N、Mg、K,其次是Zn、P。     

The Indian laburnum (Cassia fistula L.) fruit: an analysis of its chemical constituents

The edible fruit tissue of Indian laburnum fruit (Cassia fistula L.), a member of the leguminosae family, was analyzed for certain organic compounds and mineral nutrients. Of the nine macro- and micronutrients studied, K was the most highly concentrated such that 100% of the US Recommended Dietary Allowances (RDA) for adults could be met by the consumption of about 100 g of the fresh fruit. Na contents in pulp and seeds are relatively low. Ca content at 827 mg per 100 g of dry matter is one of the highest of any fruits, and could contribute towards the RDA requirement of 800 mg of Ca for adults per day. The fruit is a good source of Fe and Mn, and their concentrations are considerably higher than those found in apple, apricot, peach, pear, and orange. Aspartic acid, glutamic acid, and lysine constituted 15.3, 13.0, and 7.8% of the total amino acids respectively in the pulp. In the seeds the same amino acids constituted, 16.6, 19.5, and 6.6%. The relatively high energy content of the fruit at 18 kJ/g could enhance the daily energy requirement of people in need of adequate caloric intake. The results of the present study demonstrate that the Indian laburnum fruit could be a source of some important nutrients and energy for humans.