Bioavailability Of Zn Research Articles

Triazole fungicides in soil affect the yield of fruit, green biomass, and phenolics production of Solanum lycopersicum L.

A part of the fungicides used in foliar treatment penetrates into the soil. This study describes changes in the bioavailability of (essential) elements in soil, fructification, the amount of green biomass and the production of phenolic compounds related solely to the presence of triazoles (penconazole and cyproconazole) in soil, injected as a single compound or their mixture. The triazoles presence has substantially affected the bioavailability of Fe, Cu and Zn in soil. The amount of green biomass has significantly decreased, whereas the chlorophylls a and b have not been affected. As a potential mark of plant stress, the fruits of the treated variants are significantly bigger. The content of phenolics in tomato peel (e.g. quercetin, quercitrin, hesperidin, naringin, and chlorogenic, salicylic and p-coumaric acid) has been quantified. The biggest changes (increase/decrease) have been observed in the contents of p-coumaric and chlorogenic acid, quercetin and quercitrin.

Effect of Biochar on Growth Morphological Responses of Maize in a Naturally Contaminated Soil

Background and objectives: The presence of heavy metals in agricultural lands inevitably poses environmental pollutions. Additionally, their exposure threatens the security of healthy and marketable products. Lead and zinc are among the most common heavy metals which are found at contaminated sites, and their toxicity has turned into one of the main environmental issues in recent decades. These hazardous metals are released into the soil due to increase in human activities, including agricultural activities (application of chemical fertilizers, pesticides and herbicides) and mining activities. They exhibit toxic effects towards creatures, especially terrestrial organisms. Therefore, it is necessary to reduce metals pollution in agricultural lands. Biochar is a carbon-rich organic compound which is produced by the thermal decomposition of waste residues in an oxygen-limited environment. Showing more active functional groups, higher porous structure, and alkaline pH, biochar can reduce the risk contamination of heavy metals in the soil and, consequently retard their entry into the food chain. Materials and methods: This paper aims to investigate the effects of Walnut leaves and their biochars produced at different temperatures of 200, 400 and 600 °C on the bioavailability of zinc (Zn) and lead (Pb), as well as morphological characteristics of maize (Zea mays L. Cv. Single cross 704) grown in a highly polluted calcareous soil adjacent the Zn and Pb Bama mines. An experiment was conducted by planting maize in untreated soil (control) and soil treated with three rates (0.5, 1, and 2% w/w) of Walnut leaves and biochars. Plastic pots were filled with 3 kg of amended and un-amended soils. In order to equilibrate soil and biochars mixtures, pots were incubated for 45 days. After the incubation period, macro- and micro-nutrients were added to all treatments according to the soil test. In each pot, 3 seeds of maize were sown, and plants were grown for 8 weeks. Plants were harvested, and roots were separated from soils. The maize morphological indices were determined. Some chemical properties of soils (pH, EC, and DTPA-extractable of Pb and Zn) were analyzed after planting. Results: This study demonstrated that different pyrolysis temperatures and rates of biochar had a significant effect on the bioavailability of Pb and Zn in a highly polluted soil. Bioavailable Pb and Zn (DTPA-TEA extraction) decreased with increment in amendments rates and pyrolysis temperatures. In comparison with the control, the 2% biochar produced at 600 °C, significantly (p < 0.05) decreased the DTPA-extractable Pb and Zn by 49.1 and 34.9 %, respectively. Morphological responses showed that biochar increased the ratio of shoot to root growth significantly compared to control. Biochar also had a significant effect on leaves, stems, and roots growth. Thus, findings illustrated that biochar could immobilize Pb and Zn by reducing the bioavailability to maize and promoting plant growth. Therefore, the application of biochar in contaminated soil can reduce toxicity by decreasing the bioavailability of metals, and increasing plant growth. Conclusion: Biochar has been proven efficient in reducing heavy metals exposure and increasing phytostabilization, associated with maize's phytoremediation potential.

Effect of inorganic additives (rock phosphate, PR and boron waste, BW) on the passivation of Cu, Zn during pig manure composting

The bioavailability of heavy metals in compost is critical for their agronomic value. The effect of inorganic additives (rock phosphate, PR and boron waste, BW) on Copper (Cu) and Zinc (Zn) bioavailability during co-compost of swine manure and rice straw was assessed using sequential extraction procedure (European Community Bureau of Reference). The result showed that both additives, applied at rates of 2.5%–7.5% (w/w) could promote the change of exchangeable Cu and reducible Cu into oxidizable Cu, thereby reducing their bioavailability factor (BF) by 15.5%–47.2%. While additives provided no significant reduction in BF of Zn, the shift from exchangeable Zn into reducible Zn can still reduce the mobility of Zn. Based on redundancy analysis (RDA), organic matter (OM) and electrical conductivity (EC) were identified as the most important controlling factors for redistribution of Cu and Zn fractions during composting. The inorganic additives strengthened the passivation of Cu and Zn bioavailability by stimulating OM degradation. The 7.5% (w/w) rock phosphate showed best passivating effect on the bioavailability of Cu.

Distribution of iron, zinc and manganese in milling streams of common Serbian wheat cultivars: Preliminary survey

SummaryThis study investigates distribution of three micronutrients in milling streams of three common wheat cultivars to estimate nutritive value of white and brown flours. Among the analysed wheat cultivars, the majority of flour streams of NS Todorka showed a higher content of soluble micronutrients than the other two investigated wheat cultivars. It is necessary to improve bioavailability of Fe and Zn in flours since these micronutrients were mostly in insoluble form. In contrast, considering average Serbian portion sizes for bread, bread made from flour Type ‘110’ could supply almost 75% of the recommended daily intake for Mn.

New Insights into Health Risk Assessments for Inhalational Exposure to Metal(loid)s: The Application of Aqueous Chemistry Modelling in Understanding Bioaccessibility from Airborne Particulate Matter

Aqueous modelling of chemical speciation in simulated lung fluid (SLF) enables a better understanding of the underlying chemical factors that influence metal(loid) inhalation bioaccessibility from airborne particulate matter. Such an approach can be used to supplement experimental techniques that are integral to the health risk assessment of metal(loid) exposure by inhalational routes. In this paper, we modelled the aqueous chemistry of airborne particulate-bound metal(loid)s (As, Cu, Mn, Pb and Zn) in a SLF based on Gamble’s solution (neutral pH). The modelling was performed using two software packages (Geochemist’s Workbench 14 and OLI Studio 9.5) and a total of five thermochemical databases (GWB Thermo, MINTEQ, PHREEQC, WATEQ4F and the default database for OLI Studio). Modelled results were compared with experimentally determined bioaccessibilities for the NIST 2710a standard reference material (SRM) and with literature-reported bioaccessibilities for NIST 1648a and BCR 038 SRMs. Whilst the models correctly describe the observed increase in bioaccessibility for more dilute solid/liquid extraction ratios, the performance of the models against the fractional bias of the mean (FBmean) and the normalised mean square error (NMSE) statistical metrics was generally outside the acceptance criteria. Findings from an analysis of the main aqueous chemical species predicted to be present in SLF indicate that carbonate and chloride complexes of Cu, Mn, Pb and Zn predominate, whilst free cations (for Cu, Mn and Zn) and hydroxides (for Cu) also play a role in solubilisation. Arsenic is not predicted to form significant complexes with the SLF components and is present in solution mainly as the HAsO42− ion and its conjugate acid, H2AsO4−. For modelled runs where glycine and citrate were present, significant increases in the bioavailability of Cu and Zn were predicted as a result of complexation with these ligands. An additional finding from our experimental bioaccessibility results for NIST 2710a was that the inclusion of the lung fluid surfactant dipalmitoylphosphatidylcholine (DPPC) in the SLF did not significantly affect the bioaccessibility. Our study provides useful insights into the likely aqueous- and solid-phase speciation of metal(loid)s in SLF and highlights that future developments in this area should consider the role of mineralogy and surface interactions.

Bioavailability of soil Cu, Fe, Mn and Zn from soil fractions

Cationic micronutrients bioavailability depends on the chemical characteristics of soil fractions. Fourteen soils received individual doses of five micronutrients (Cu, Fe, Mn, Zn, B) arranged in seven treatments set according a Baconian Matrix. The soils incubated with treatments during 15 days had corn cultivated in greenhouse for 30 days, in three consecutive growth cycles. The cationic micronutrients were determined in the corn shoots after each growth cycle. Soil samples collected before the first and after each growth cycle had the available concentrations of Cu, Fe, Mn and Zn determined by single extractions (Mehlich-1 and DTPA-pH 7.3) and by sequential extraction. Correlation analysis was performed for the Cu, Fe, Mn and Zn concentrations determined in the corn shoots, the available concentrations of Cu, Fe, Mn and Zn in the soils (Mehlich-1 and DTPA) and the concentrations of Cu, Fe, Mn and Zn in the soil fractions (sequential extraction). The distribution of available metals forms in fractions reflected their affinity with soil components. Soil available Cu correlated with Cu bound to organic matter. The exchangeable fraction was the main source of soil available Mn and Zn. The Fe availability related mainly to the Mn oxides, Fe oxides, and exchangeable fractions. The plants absorbed Cu mainly from the Mn-oxides and organic matter fractions. Manganese absorbed by plants originated from the exchangeable and Mn-oxides fractions. The Zn absorbed by plants originated mainly from the exchangeable fraction. Correlations of single metal extractions (Mehlich-1 and DTPA) with Cu, Mn and Zn contents in plants were positive.

Strong phosphorus (P)-zinc (Zn) interactions in a calcareous soil-alfalfa system suggest that rational P fertilization should be considered for Zn biofortification on Zn-deficient soils and phytoremediation of Zn-contaminated soils

Zinc (Zn) and phosphorus (P) often interact negatively with each other in soil-plant systems. We investigated the effects of P-Zn interaction on Zn and P accumulation and partitioning in alfalfa. Plants were grown in a calcareous soil supplied with different rates of Zn (0, 200, and 800 mg kg−1) and P (0, 20, and 80 mg kg−1). Plant dry mass, Zn and P concentrations in shoots and roots, bulk soil and rhizosheath pH, rhizosheath carboxylates, and DTPA-extractable Zn concentration in the bulk soil were determined. Phosphorus-Zn interaction significantly affected DTPA-extractable Zn concentration, plant dry mass, accumulation of Zn and P, and partitioning of Zn in alfalfa, but did not affect rhizosheath pH or the amounts of rhizosheath carboxylates. Increasing P rate promoted plant growth at all soil Zn rates and might enhance the plants’ capacity to cope with excessive Zn; it resulted in a lower rhizosheath pH, which likely contributed to greater Zn and P uptake. Zinc deficiency enhanced exudation of citrate, malonate and malate, while the release of tartrate was related with P deficiency. There are strong P-Zn interactions in calcareous soil-plant system, such interactions significantly affect Zn bioavailability, plant growth, accumulation of Zn and P, and partitioning of Zn in alfalfa. Rational P fertilization should be considered for efficient Zn biofortification on Zn-deficient soils and phytoremediation of Zn-contaminated soils.

Influence of Soil Type on the Reliability of the Prediction Model for Bioavailability of Mn, Zn, Pb, Ni and Cu in the Soils of the Republic of Serbia

The principles of sustainable agriculture in the 21st century are based on the preservation of basic natural resources and environmental protection, which is achieved through a multidisciplinary approach in obtaining solutions and applying information technologies. Prediction models of bioavailability of trace elements (TEs) represent the basis for the development of machine learning and artificial intelligence in digital agriculture. Since the bioavailability of TEs is influenced by the physicochemical properties of the soil, which are characteristic of the soil type, in order to obtain more reliable prediction models in this study, the testing set from the previous study was grouped based on the soil type. The aim of this study was to examine the possibility of improvement in the prediction of bioavailability of TEs by using a different strategy of model development. After the training set was grouped based on the criteria for the new model development, the developed basic models were compared to the basic models from the previous study. The second step was to develop models based on the soil type (for the eight most common soil types in the Republic of Serbia—RS) and to compare their reliability to the basic models. From the total number of developed models by soil type (80), 75% were accepted as statistically reliable for predicting the bioavailability of TEs by soil type and 70% of prediction models had a higher determination coefficient (R2), compared to the basic models. For the Fluvisol soil type, all prediction models were accepted, while the least reliable prediction was for the Planosol type. As in the previous study of bioavailability prediction for TEs, the prediction models for Cu stood out, with more than half of the models with R2 greater than 0.90. Results of this study indicated that the formation of a testing set by soil type derives models whose predictions are more reliable than the basic ones. To improve the performance of prediction models, it is necessary to include additional physicochemical parameters and to conduct an adequate analysis of extensive testing sets with more comprehensive statistical techniques.

Expanding information on the bioaccessibility and bioavailability of iron and zinc in biofortified cowpea seeds

This work presents new findings on the nutritional quality of recently introduced biofortified and non-biofortified cowpea cultivars as well as some common beans. ICP-MS was used for the measurements. Biofortified cowpea cultivars showed high levels of Fe and Zn, greater than 60 and 40 mg kg−1 dry weight, respectively. The in vitro digestion protocol enabled simultaneous evaluation of bioaccessibility and bioavailability. Fe levels in cowpea cultivars were ca. 2.5-fold higher than in common beans. Cowpea seeds also had higher Zn levels, reaching 50.1% bioaccessibility and 44.2% bioavailability. Cooking improved the availability of micronutrients in bean seeds. The cooked biofortified Aracê cowpea showed a high Zn bioavailability above 60%. Consumption of 50 g of Aracê would contribute 27% and 48% of the Fe and Zn DRI for 1–3-year-old children. The new cowpea cultivars biofortified are a potential vehicle for improving the Fe and Zn status in groups in which the micronutrient deficiency is prevalent.

The Effect of Composting on the Multiple Heavy Metals in the River Sediment Investigated by Multivariate Analysis

This study investigated the passivation of multiple heavy metals (Cd, Cr, Cu, Zn, and Pb) in river sediments by composting with rice straw. The correlation between the selected environmental factors and the distribution of heavy metal fractions was assessed by multivariate analysis. The results suggested that the composting could reduce the bioavailability of Cu, Cd, Cr, and Pb. The influences of composting on the passivation of these five heavy metals are different. The greatest passivation of heavy metals is for Cd, which its bioavailability decreased 17.72%. The bioavailability of Cu, Pb, and Cr also partly decreased. However, there was almost no effect on the bioavailability of Zn. The results of multivariate analysis revealed that the predominant parameters affecting the variation of the bioavailability of different heavy metals were different in a complex composting system with multiple heavy metal pollution. While the variation partitioning analysis indicated that water-soluble carbon (WSC) was the statistically main factor affecting the bioavailability of Cd, Cr, Cu, Zn, and Pb. It provides a theoretical reference for optimizing the co-composting process in remediation of different heavy metal contamination in sediments.

Genotypic variability of grain phytic acid, mineral bioavailability, and their relation to foliar Zn application

Phytic acid (PA) is the most prevalent storage form of grain phosphorus (P) and acts as an anti-nutrient by lowering mineral bioavailability. Genotypic variation of grain PA and its relation to mineral bioavailability, and their nutritional fortification potential with zinc (Zn) supply has not been fully investigated in pigmented rice. Here, we compared the differences in grain PA concentration and mineral bioavailability among 13 pigmented rice (red, yellow, and green rice) and six non-pigmented rice cultivars (three common white rice and their corresponding low-PA (lpa) mutant). Pigmented rice was enriched with micronutrients, especially Zn and Fe, on an average of 39.1 and 44.8 mg kg−1 as compared with 31.9 and 33.1 mg kg−1 in non-pigmented rice respectively. The lpa cultivars showed the highest bioavailability for most of the minerals. However, no significant difference was observed for mineral bioavailability between pigmented and common white rice, owing to higher anti-nutritional PA in pigmented rice (9.25 g kg−1) than in common white rice (8.29 g kg−1). However, a large difference in grain PA was found among green rice (11.19 g kg−1), yellow rice (9.82 g kg−1) and red rice (8.56 g kg−1) cultivars. Therefore, foliar Zn was used to investigate PA concentration and Zn bioavailability. Foliar Zn application increased grain Zn but decreased grain PA concentration, which ultimately increased grain Zn bioavailability. Zn application had a remarkable effect on Zn bioavailability for red rice (an average of 82%) as compared with common white rice (48%). These findings could provide helpful knowledge for pigmented rice fortification.

Higher bioavailability of Cu and Zn in the eastern part of Johore Causeway: Will the pattern remain the same beyond 2030?

The purpose of this paper is to discuss Cu and Zn concentrations in Perna viridis soft tissues from the western and eastern parts of Johore Singapore Causeway. The polluted eastern portion of the Causeway had greater levels of Cu and Zn in different areas of the soft tissues of mussels than the western part. This indicated the eastern section of the semi-enclosed Causeway had higher Cu and Zn bioavailability than the western part. With some reports of high metal levels in the eastern part of the Causeway from 2015 to 2018, it is predicted that there will be a plausible constant source of anthropogenic metal contamination in the eastern part of the Causeway beyond 2030 if anthropogenic activities are not effectively controlled.

Chemical and nutritional characterization of bean genotypes (&lt;i&gt;Phaseolus vulgaris&lt;/i&gt; L.)

&lt;abstract&gt; &lt;p&gt;Beans (&lt;italic&gt;Phaseolus vulgaris&lt;/italic&gt; L.) are the most important legume for human consumption, and have essential nutrients for physiological processes. As examples, we can mention Fe and Zn. As a strategy to increase these nutrients in the population's diet, beans stand out as a potential candidate, as it already has high levels of these minerals compared to other foods. The objective of this study was to evaluate 14 bean genotypes from the EPAGRI Bean Genetic Improvement Program, Brazil, regarding Fe and Zn content, availability of Fe and Zn in vitro, amount of phytic acid, tannins, proteins, and moisture. The results showed a high positive correlation between the total amount of Zn with bioavailable Zn; the total amount of Fe, and the total amount of Zn; and the total amount of bioavailable Fe with Zn. Furthermore, there were statistically significant differences for all characteristics evaluated, showing an interesting variability that can be considered for future crosses aiming at nutritional quality.&lt;/p&gt; &lt;/abstract&gt;

Bioavailability and Solubility of Heavy Metals and Trace Elements during Composting of Cow Manure and Tree Litter

Objectives. To characterize the total content of heavy metals (Cd, Cr, Cu, Hg, Mo, Ni, Pb, and Zn) and trace elements (As and Se) of interest, their bioavailability and solubility during the composting of cow manure and tree litter in piles inoculated with beneficial microorganism (IBM), or not inoculated (NBM), on the university campus of the Universidad Nacional Agraria La Molina (UNALM). Methods. The investigation evaluated composting in six piles, three IBM piles and three NBM piles, for 120 days. Every 30 days, a composite sample was taken from each pile. The raw materials used were cattle manure and tree litter. The variables analyzed were the total concentrations (content) of metals and trace elements of interest, extracted with diethylenetriaminepentaacetic acid/pentatetic acid (DTPA) (for the bioavailability study) and extracted with deionized water (for the solubility study). Results. The average values (n = 3) of the total content (mg·kg−1) on day 120 in IBM were in the following order: Zn (404.33) &gt; Cu (86.33) &gt; Pb (71.2) &gt; Cr (34.33) &gt; As (28.0) &gt; Ni (13.83) &gt; Mo (2.86) &gt; Se (1.38) &gt; Cd (1.32) &gt; Hg (0.39) and in NBM: Zn (466.0) &gt; Cu (112.23) &gt; Pb (73.23) &gt; Cr (35.33) &gt; As (29.67) &gt; Ni (14.37) &gt; Mo (3.23) &gt; Se (1.55) &gt; Cd (1.38) &gt; Hg (0.38). The values complied with the Austrian Compost Standard for Landscaping and Land Rehabilitation and the Peruvian Standard for Nonorganic Agriculture. Significant differences were observed in some elements ( p &lt; 0.05) between 0 and 120 days in both types of pile (IBM and NBM). Conclusions. For nonorganic agriculture in Peru, urban compost is recommended, whereby raw organic materials are inoculated with beneficial microorganisms during the composting process to reduce the bioavailability of Cu and Zn, as these elements showed less bioavailability than noninoculated piles. The composting process for both piles (IBM and NBM) reduced the solubility in Cu, Pb, and Zn.

Agronomic Biofortification of Zinc in Pakistan: Status, Benefits, and Constraints

Micronutrient malnutrition (e.g., zinc) is one of the major causes of human disease burden in the developing world. Zinc (Zn) deficiency is highly prevalent in the Pakistani population (22.1%), particularly in women and children (under 5 years) due to low dietary Zn intake. In Pakistan, wheat is the primary staple food and is poor in bioavailable Zn. However, the number of malnourished populations has decreased over the last decade due to multiplied public awareness, accelerated use of Zn fertilizers (particularly in wheat and rice), initiation of several national/international research initiatives focusing on Zn biofortification in staple crops and availability of supplements and Zn fortified meals merchandise, nonetheless a large number of people are facing Zn or other micronutrient deficiencies in the country. There are few reports highlighting the significant increase in daily dietary Zn uptake in population consuming biofortified wheat (Zincol-2016) flour; indicating the positive prospect of biofortification interventions up scaling in lowering the risk of dietary Zn deficiency in rural and marginalized communities. Zinc fertilizer strategy has not only helped in enhancing the grain Zn concentration, but it also helped in improving crop yield with high economic return. In addition, Zn biofortified seeds have exhibited strong inherent ability to withstand abiotic stresses and produce higher grain yield under diverse climatic conditions. However, there are many constraints (soil, environment, genetic diversity, antinutrients concentration, socioeconomic factors etc.) that hinder the success of biofortification interventions. This review highlights the status of Zn deficiency in Pakistan, the success of agronomic and genetic biofortification interventions. It also discusses the economics of agronomic biofortification and cost effectiveness of Zn fertilization in field conditions in Pakistan and the potential of Zn biofortified seeds against abiotic stresses. Furthermore, it also highlights the constraints which limit the sustainability of biofortification interventions.

Zinc solubilizing Pseudomonas spp. from vermicompost bestowed with multifaceted plant growth promoting properties and having prospective modulation of zinc biofortification in Abelmoschus esculentus L

Zinc is an essential micronutrient necessary for the optimal development and yield of Okra (Abelmoschus esculentus L.). Plants absorb zinc in soluble form as Zn2+; a large amount of zinc in the soil are in insoluble forms. Zinc solubilizing microbes could be substitutes for zinc fertilizers and transform inorganic zinc into plant accessible forms. The study was aimed to isolate and screen a range of Zinc solubilizing bacteria (ZSB) from vermicompost for their plant growth-promoting properties with okra. Thirty bacterial isolates from vermicompost were examined for zinc solubilization with ZnO and ZnCO3 using dilution plate method on Kings B medium. Two strains, i.e., VBZ4 and VBZ17, were found most prevalent Zn solubilizing isolates with 32 mm and 43 mm solubilization zone for ZnO supplemented media. Atomic absorption spectroscopy (AAS) was used for quantitative assessment of Zn solubilization, where VBZ4 displayed significantly higher solubility of ZnO (26.8 ppm) compared with VBZ17 (22.2 ppm). The quantitative results of plant growth promotion characters showed that VBZ4 and VBZ17 isolates to solubilize the maximum amount of phosphate with 316.72 μg/ml and 214.0 μg/ml, and indole acetic acid production, 10.2 μg/ml and 17.1 μg/ml respectively. Further, ZSB isolates were introduced with Okra seeds under pot experiment, where treatment P4 (seeds + VBZ4 + VBZ17) found significantly effective on plant growth and maximum zinc content in Okra fruit (2.85 mg/100g) compared to control. Application of these bacteria may help to provide sufficient amounts of Zn bioavailability, including improved plant growth in a sustainable manner.

A Comparative Study of the Bioavailability of Fe, Cu and Zn from Gluten-Free Breads Enriched with Natural and Synthetic Additives

The aim of this study was to compare the bioavailability of iron, copper and zinc from newly designed gluten-free breads enriched with natural and synthetic additives. The study was conducted on rats with induced Fe, Cu and Zn deficiency. The nutritional intervention with diets supplemented with a 70% addition of gluten-free breads enriched with natural additives and organic compounds to the control diet AIN-93M lasted 40 days. After the intervention, the rats were euthanized, the organs were collected and their mineral content was measured. Chemical analysis of diets with the addition of fortified gluten-free breads showed significantly higher amounts of iron, zinc and copper in diets with the addition of fortified breads compared to diets with the addition of unenriched breads. The type of additives did not influence the amount of minerals in diets. It is necessary to conduct further research to explain the interactions of ingredients and the factors affecting the bioavailability of Fe, Cu and Zn from gluten-free breads in order to obtain a product with a high bioavailability of these ingredients.

Amino Acid Profile, Mineral Bioavailability, and Sensory Properties of Biscuits Produced from Composite Blends of Wheat, Coconut and Defatted Fluted Pumpkin Seed Flour

The objective of this work was to produce biscuits from composite flour of wheat, coconut, and defatted fluted pumpkin seed and to evaluate the mineral bioavailability, amino acid profile and sensory properties of the composite biscuits. Wheat/coconut/defatted fluted pumpkin seed flours were blended in the ratio; 100/0/0, 80/10/10, 70/20/10, 60/30/10, 50/40/10, 40/50/10 and labelled as sample A, B, C, D, E and F respectively. Biscuits were baked with these composite flours using the creaming method. Lysine content ranged from 3.35-5.07g/100g, with sample F given significantly higher value followed by samples E (4.70g.100g) and D (4.33g/100g). All the essential amino acids increased significantly with increased substitution of coconut and fluted pumpkin seed flour, except phenyl-lanine and cysteine that decreased from 4.98 – 3.90 and 1.22 – 0.69g/100g respectively in sample A to E. Sample E gave higher total Ca, Fe, K and Zn of 26.89, 17.92, 86.02 and 2.82mg/100g respectively. Percentage bioavailability of Ca, Fe, Na, K and Zn were significantly higher in sample F with values of 59.67, 51.35, 58.22, 59.67 and 47.74% respectively. Sample E recorded the highest overall acceptability score of 6.38. This score was however not significantly different from scores obtained for samples A, B, C and D. Production of composite biscuits with 50/40/10% wheat/coconut/defatted fluted pumpkin seed flour is highly recommended.

The effectiveness of foliar applications of different zinc source and urea to increase grain zinc of wheat grown under reduced soil nitrogen supply

Nitrogen is important for the enrichment of grain Zn when Zn is foliarly applied. However, decreasing soil N input has become a major issue for environmental protection. A 2-yr field experiment was conducted to evaluate the effectiveness of spraying different Zn sources [ZnSO4 or Zn(Gly)2] combined with or without urea on grain Zn concentration and bioavailability under reduced soil N rates, both in single wheat plantation and winter wheat-summer maize rotation. Results showed that foliar application of Zn(Gly)2 significantly increased grain Zn concentration by 88% under wheat-summer maize rotation and 150% under single wheat plantation. The effectiveness of foliar ZnSO4 application in increasing grain Zn was similar with that of Zn(Gly)2. Adding urea to foliar ZnSO4 or Zn(Gly)2 further increased grain Zn concentration under reduced soil N rates. Grain Zn biavailability increased with the reduction of soil N rates, but decreased after application of foliar Zn fertilizers. Foliar fertilization significantly increased protein, Fe, and Mn concentrations in grain, and the magnitudes of these increases were greater when Zn(Gly) 2 alone or ZnSO 4 plus urea were applied. Simultaneous foliar application of ZnSO4 and urea slightly increased farmer’s net income. These results suggest that foliar application of ZnSO 4 plus urea can be used as efficient and economical fertilization strategies to increase Zn concentration and bioavailability in wheat grain under reduced soil N supply, and consequently minimize Zn deficiency in humans.

Comparison of ashing and pyrolysis treatment on cadmium/zinc hyperaccumulator plant: Effects on bioavailability and metal speciation in solid residues and risk assessment.

Phytoremediation of metal(loid)s contaminated sites is widely used, while there is scarce of investigation on the metal-enriched biomass waste safely disposal which resulted in risks of causing secondary pollution to the soil and water bodies and even to human health. Thus, this study compared the effects of ashing and pyrolysis treatments on cadmium (Cd) and zinc (Zn) hyperaccumulation plant Sedum plumbizincicola. Chemical speciation, the Toxicity Characteristic Leaching Procedure (TCLP), and diethylenetriamine pentaacetic acid (DTPA) extraction were employed to characterize the bioavailability and leachability of Cd and Zn in the solid residues after pyrolysis and ashing. The risk assessment code (RAC) and potential ecological risk index (RI) were subsequently used to evaluate the risk of the solid residues to the environment. The results showed that both ashing and pyrolysis treatments could transform the bioavailable Cd and Zn in S.plumbizincicola into a more stable form, and the higher the temperature the greater the stablility. Pyrolysis converted a maximum of 80.0% of Cd and 70.3% of Zn in S.plumbizincicola to the oxidisable and residual fractions, compared with ashing which achieved only a ∼42% reduction. The pyrolysis process minimised the risk level of Cd and Zn to the environment based on the RAC and RI assessments. The results of the TCLP test, and DTPA extraction confirmed that the leaching rate and the bioavailable portion of Cd and Zn in the biochars produced by pyrolysis were invariably significantly (p<0.05) lower than the solid residues produced by ashing, and reached the lowest at 650°C. In other words, pyrolysis was better than ashing for thermal treatment of the metal-enriched hyperaccumulator plant, in view of minimising the bioavailability and leachability of Cd and Zn from the solid residues to the environment. This study provides fundamental data on the choice of treatments for the disposal of metal-enriched plant biomass.