The effect of formulation and amount of potassium fertilizer on macromineral concentration and cation-anion difference in tall fescue

This study investigated the feasibility of altering the dietary cation-anion difference (DCAD) in grass by altering the grass variety and the amount and formulation of K fertilizer application. In experiment 1, treatments were combinations of 2 varieties (Barcel and Hi-Mag) of tall fescue (Festuca arundinacea Schreb); 2 rates of K (0 and 250 kg/ha), supplied as KCl; and 2 rates of Mg (0 and 60 kg/ha), supplied as MgO. In experiment 2, K fertilizer was applied at 0 or 125 kg/ha as KCl or K₂SO₄. There was no difference between HiMag and Barcel tall fescue in the concentrations of Mg, S, and Cl. Application of K fertilizer decreased concentrations of Mg, but the magnitude of the decrease was not consistent across harvests. Conversely, application of Mg fertilizer increased Mg concentrations, but again, the magnitude of the increase was not consistent across harvests. The concentrations of Ca were higher in HiMag than in Barcel tall fescue, with the magnitude of the difference increasing from first to last harvest. Potassium fertilizer decreased Ca concentrations in the first, fourth, and fifth harvests only. Calcium concentration was decreased by a greater magnitude in HiMag tall fescue as a result of Mg fertilization. The HiMag tall fescue contained lower concentrations of K than did Barcel tall fescue in the first, second, and third harvests. Application of K fertilizer increased the K concentration in all 5 harvests but did not affect Na concentrations except in the last harvest. The HiMag tall fescue contained less Na than did Barcel, but the magnitude of the difference was affected by K and Mg fertilization. Application of K fertilizer decreased S concentrations in first-harvest grass, increased concentrations in second-and third-harvest grasses, and had no effect in fourth-or fifth-harvest grasses. Application of Mg fertilizer decreased S concentrations of tall fescue. Application of K fertilizer increased DCAD values for grass harvested from the second through fifth harvests. The increase in DCAD attributable to K fertilizer was less in HiMag than in Barcel tall fescue. Application of K fertilizer as K₂SO₄ increased dry matter yield and S concentrations of HiMag tall fescue, whereas K applied as KCl increased concentrations of K and Cl. There was no effect of fertilizer formulation on Na concentrations. The DCAD was lower in HiMag tall fescue fertilized with K₂SO₄ compared with that fertilized with KCl. This study showed that DCAD of grass can be manipulated by the choice of grass variety, fertilizer formulation, and fertilizer application rate.     

Cultural Methods and Mineral Content of Eggplant (Solanum melongena) Fruit

Mineral content in edible portions of vegetables may be affected by cultural methods. This study was conducted to determine if fertiliser rate and irrigation regime affected mineral (N, NO₂, NO₃, P, PO₄, K, SO₄, Ca, Fe, Na, Mg, and Mn) of eggplant ( Solanum melongena L, cv Black Bell) fruit. The experiment on a Bernow fine-loamy, siliceous, thermic Glossic Paleudalf soil at Lane (OK, USA) with three fertiliser rates and three irrigation regimes. The data were analysed as a split-plot with harvests as the sub-plot. All P was accounted for by PO₄. Levels of NO₂ and NO₃ comprised <0·001% of the N content. Harvest number affected only N, P, K, SO₄ and Mg levels in both years, and Na in one year. For many of the minerals the highest levels in fruit were not consistent over harvests in both years. When there was less precipitation, and fertiliser was applied at the recommended rate, fewer irrigations per week were necessary to increase levels of N, P and K in fruit. The interaction of irrigation and fertiliser can affect mineral content of fruit and should be considered when fertiliser recommendations are made.     

Solid phase extraction with flame atomic absorption spectrometry for determination of traces of Ca,K, Mg and Na in quality control of white sugar

A fast and straightforward pre-concentration procedure based on solid phase extraction with a strongly acidic cation-exchanger Dowex 50 W × 8–400 was proposed to determine traces of Ca, K, Mg and Na in white sugar samples by means of flame atomic absorption spectrometry. For this purpose, 20% (m/v) white sugar solutions (100 ml) were driven through resin beds at 10 ml min⁻¹ to retain Ca, K, Mg and Na ions and to separate sucrose that passed through unretained. Thereafter, columns were rinsed with water and elements of interest were recovered prior to measurements using 5 ml of a 2 mol l⁻¹ HCl solution. Detection limits of 0.04, 0.05, 0.02 and 0.01 μg g⁻¹ for Ca, K, Mg and Na, respectively, and precision of measurements within 1–3% were achieved. The proposed method enabled to determine Ca, K, Mg and Na in samples of white sugar within corresponding ranges: 0.66–0.99 μg g⁻¹ (Ca), 2.9–12.2 μg g⁻¹ (K), 0.53–1.57 μg g⁻¹ (Mg) and 0.06–0.30 μg g⁻¹ (Na). Accuracy of this sample pre-treatment procedure and analysis method was assessed by performing spikes and recovery experiments. Recoveries of added Ca, K, Mg and Na were found to be within 97–102%, demonstrating good reliability of results.     

Effect of calcium on mineral nutrient uptake and growth of tobacco

The aim of this work was to analyse the dynamics of the nutritional state and biomass production in tobacco plants resulting from the application of various calcium levels (Ca1, 1.25 mol m^?3 CaCl₂; Ca2, 2.50 mol m^?3 CaCl₂; Ca3, 5 mol m^?3 CaCl₂) in the culture medium. Tobacco plants were grown under controlled conditions and submitted to regular fertilisation with macro‐ and micronutrients. The concentrations of Ca, organic N, P, K, Na, Mg, Fe, Mn, Zn, Cu, Cl and B were determined in the roots and leaves. As expected, Ca accumulated progressively with increasing concentration of this element in the culture medium. There was a slight rise in the concentration of organic N but hardly any change in the concentrations of K and Na. In contrast, increasing Ca application caused a gradual decline in P and Mg concentrations. In terms of micronutrient concentrations, Fe, Mn, Zn, Cl and B were influenced positively by Ca treatment. A noteworthy synergetic relationship was found between Ca and B. In contrast, the Cu concentration in the roots declined significantly with increasing Ca application. The effect of Ca on biomass production depended on the organ analysed, since the dry matter content diminished in the roots but was augmented slightly in the leaves. © 2001 Society of Chemical Industry     

Simultanbestimmungsmethoden für die Elemente Kupfer,Zink, Eisen und Mangan sowie Natrium,Kalium, Calcium und Magnesium mittels Flammen-Atomabsorptionsspektrometrie (F-AAS)

Simultaneous determination of the elements copper, zinc, iron and manganese as well as sodium, potassium, calcium and magnesium by flame atomic absorption spectrometry (F-AAS). The elements Na, K, Ca, Mg, Cu, Zn, Fe and Mn are very important for the examination of human food and foodstuff in the light of nutritional physiology. Two simultaneous determination methods for these elements with flame atomic absorption spectrometry (F-AAS) are presented. The sensitivity of the F-AAS is sufficient for these examinations. Using the calibration and the method of standard addition resp. and “Schinkellösung” (caesiumchlorid lanthanumchlorid buffer solution), the simultaneous determination of Na, K, Ca and Mg is possible. The detection limits of Na, K, Ca and Mg depend on the simultaneous determination of the elements, the used wavelengths and the kind of the examined samples (30 mg Na, 24 mg K, 1,9 mg Ca and 0,46 mg Mg per kg fresh matter). The detection limits for Cu, Zn, Fe and Mn with the simultaneous determination are 0,61 mg Cu, 0,14 mg Zn, 3,8 mg Fe and 0,44 mg Mn per kg sample. The new methods are tested with the standard reference materials CRM No 278 (Mussel Tissue), CMR No 185 (Bovine Liver) and CRM No 189 (Wholemeal Flour) and with selected samples.     

Flavoured versus natural waters: Macromineral (Ca,Mg, K,Na) and micromineral (Fe,Cu, Zn) contents

Macro (Ca, Mg, K, Na) and micromineral (Fe, Zn, Cu) composition of 39 waters was analysed. Determinations were made by atomic flame spectrophotometry for macrominerals and electrothermic atomisation in graphite furnace for microminerals.     

Changes of Mineral Concentrations in Serra Cheese during Ripening and Throughout the Cheesemaking Season

Seasonal changes of the ash content and mineral concentrations in Serra cheese were studied over a typical 35-day ripening period. Statistically significant differences (at the 5% level) exist between the ash content and the concentrations of Na, K, Ca, P, Mg and Zn in cheeses during ripening. The highest concentrations of Na was obtained in cheese ripened for 7 days, whereas the concentrations of K, Ca, P, Ng and Zn decreased significantly during ripening. For 35-day-old cheeses, concentrations of Na, K and Cu were lowest and concentration of P was highest for cheeses manufactured in May. The concentration of Ca was lowest for cheeses manufactured in February. On average, the most concentrated minerals (in g kg^-1 of total solids, TS) in 35-day-old Serra cheese were Na (18·56), Ca (9·70) and P (7·92) and, at a lower level, K (1·70) and Mg (0·96). Only trace levels (in mg kg_TS^-1) of Zn (94·33), Cu (2·26) and Mn (1·25) were detected. A high mineral nutrition quality was thus ascribed to 35-day-old Serra cheese based on the average nutritional densities: 4·8 for Ca, 4·0 for P, 1·1 for Mg, 3·4 for Na, 2·4 for Zn, 0·4 for Cu, 0·2 for Mn and 0·2 for K. © 1997 SCI     

Desorption of cations from scottish soils by electro-ultrafiltration

Soil cations were desorbed by electro-ultrafiltration (EUF), i.e. by applying an external electric field to aqueous suspensions, and collecting the cations by ultrafiltration. Three different field strengths were used to obtain several cation fractions in a single extraction run lasting 35 min. Potassium desorbed in 10 min (K₁₀) was closely correlated with the equilibrium activity ratio (AR₀) of soil K measured in 0.01M CaCl₂, for all but the sandy loam soils, while that desorbed in 35 min (K₃₅) was less than the exchangeable K, but correlated closely with it. EUF values compared favourably with other soil K parameters, determined by conventional methods, for predicting uptake of K by rye-grass from ten soils during intensive cropping in the glasshouse. Sodium desorbed in 35 min (Na₃₅) approximated to the exchangeable Na, although most of it was desorbed in the first 15 min. Na₁₀ and Na₃₅ accounted for about 56% of the variation in Na uptake by ryegrass at the first cut, and 68% of the variation in the cumulative uptake at the sixth cut. Between 9–24% of the exchangeable calcium was desorbed in 35 min, and magnesium desorbed was closely correlated with both the Mg concentration of the soil saturation extract and the exchangeable Mg. EUF extraction of Mg is less satisfactory than for K, Na and Ca owing to the precipitation of Mg(OH)₂ on the cathode filter.     

Influence of species,harvest date and size on composition of capers (Capparis spp.) flower buds

Physical and chemical properties of raw flower buds at three different sizes (x ≤ 8 mm, 8 < x ≤ 13 mm, x > 13 mm) of Capparis spinosa var. spinosa and Capparis ovata var. canescens harvested in June and August were determined. C. Spinosa buds were more firm and spherical than C. ovata. Water, crude fiber, crude oil, total carotenoids and starch values of species in both harvests increased as bud size increased. All materials contained high amounts of Na, K, P, Ca, Mg and Mn, but decreasing Mn in August. Small buds harvested in June were more suitable to processing for physical and chemical properties. Values of analyses were variously affected by species, size and harvest date.     

Metal contents in “oloroso” sherry wines and their classification according to provenance

“Oloroso” sherry wines, belonging to the denominations of origin Jerez-Xérès-Sherry (JX), Montilla-Moriles (MM) and Condado de Huelva (CH) (Andalusia, Spain), were analysed for their contents of Ca, Mg, Fe, Cu, Mn and Zn by flame atomic absorption spectrophotometry, and Na, K, Al and Sr by flame atomic emission spectrophotometry. Among the three denominations of origin, differences in the mean contents were found for Na, Mg, Fe, Al and Sr. Cluster analysis showed that these differences were significant. Linear discrimination analysis, using Na, Mg, Fe, Al and Sr, gave 100% recognition ability and 93% prediction ability.     

Mineral profile of “fino” wines using inductively coupled plasma optical emission spectrometry methods

Fifty wines from the Denomination of origin (DO) of Condado de Huelva were analysed for mineral content by measuring 12 elements (Al, Ba, Ca, Cu, Fe, K, Mg, Mn, Na, P, Sr and Zn) using Inductively Coupled Plasma-Optical Emission Spectrometry (ICP-OES). Samples were previously digested by heating with H₂O₂/HNO₃ mixture. The results obtained showed that metal data set were non-normally distributed and accordingly, non-parametric statistics were applied. The average levels (medians) of these elements found in the samples are as follows, in mg/L: 2.54 (Al); 0.06 (Ba); 82.58 (Ca); 0.21 (Cu); 3.53 (Fe); 865.34 (K); 68.87 (Mg); 0.71 (Mn); 32.77 (Na); 71.61 (P); 0.48 (Sr); 0.56 (Zn). The interrelation of metal couples was studied through the Spearman non-parametric sample correlation, being Fe/Al, P/Mg, and Zn/Ba the most important correlations established. As a result of this study, we can suggest that the contribution to the safety intake limits (per week) of the studied elements through the wine consumption is not significant. Actually, they range between 0.1% in Fe and 11.9% in Mg, for normal drinkers.     

超声提取-电感耦合等离子体质谱法快速测定卷烟纸中钾、钠、钙、镁的含量

采用超声提取-电感耦合等离子体质谱法能快速测定卷烟纸中钾（K）、钠（Na）、钙（Ca）、镁（Mg）含量,控制卷烟纸的质量稳定性。检出限分别为2.46、0.44、8.84、0.28 μg/L;回收率90.3%~109.0%;相对标准偏差（RSD）<5%。此方法具有操作简单、准确、快速等优点,适合于卷烟纸中K、Na、Ca、Mg含量的分析。     

Effects of Salts and pH on Heating-Related softening of Snap Beans

The effects of salts and pH on softening during cooking were tested by modifying solutions in which pods were heated. Ca displacement was minimized by soaking heated pods in 0.2M CaCl₂ before measuring firmness. Softening was increased independently by the presence of salts and when pH was raised from 5.2 to 6.2. Cations decreased firmness in the order Li > Na = K > NH4 and Ca > Mg. Anions decreased the firmness in the order SO₄ > acetate > CI > NO₃. Firmness differences persisted at long heating times. The results support the hypothesis that pectin β-elimination was the principal softening reaction.     

Mineral contents of some southern Italian wines. II. Determination of Li, Na, Mg, K, Ca, Co, As, Rb, Sr, Ag, Sb, Ba

Following our study of the mineral contents of some Southern Italian wines, this work reports on the detection of 12 elemental components. The elements were determined using ICP-AES, flame atomic emission or absorption spectroscopy. The values determined for Li, Na, Mg, K, Ca, Rb, Sr and Ba were within the usual ranges for wines (average values for these elements were: 0.010, 26.2; 94.4; 888; 94.0; 3.30, 0.82 and 0.11 mg/l respectively). All the wines contained low levels of As, the concentrations of which were always under 0.20 mg/l, the maximum level permitted by E.E.C. standards. The measuring of Co, Ag, and Sb led us to ascertain, in all the wines, concentrations lower than 0.01 mg/l for Co and Ag and below the instrumental detection level for Sb (0.06 mg/l). In a previous study wines from D.O.C. areas of Southern Italy were analysed by the technique of inductively coupled plasma atomic emission spectroscopy (ICP-AES), for 14 minerals. This paper deals with further investigation of the mineral composition of the same wines for different metal constituents, analysed by ICP-AES, flame atomic emission, or atomic-absorption spectroscopy (two techniques). The first technique was applied to the detection of Co, As, Sr, Ag, Sb, and Ba. The alkaline metals Li, Na, K, and Rb were determined by flame atomic emission, a technique which possesses better detection limits for these elements. For Mg and Ca the atomic absorption methods were applied.     

Influence of banded fertiliser on the chemical environment surrounding the band. II. Effect on soil-solution cations,cation—anion balance and solution phosphorus

The influence of several banded fertilisers on soil solution content of Ca, Mg, K, P and on cation-anion balance at two distances from the band was studied. Treatments consisted of various combinations of monocalcium phosphate (MCP), KCl, NH₄NO₃, (NH₄)₂HPO₄ and urea applied on a nutrient element basis of 22.4 or 67.2 kg/ha. Ammonium nitrate or KCl, supplied separately, produced the highest solution concentrations of Ca (up to 1200 parts/million) and Mg (up to 500 parts/million). Solution concentration of Ca and Mg increased over a 32-day incubation time near treatments containing urea. Treatments containing (NH₄)₂HPO₄ initially reduced solution Ca and Mg contents only when applied at 67.2 kg/ha. All treatments not containing K had similar but smaller effects on solution K than they did on Ca and Mg. Highly significant correlations were obtained between total mequiv. of Ca+ Mg and NO₃ for treatments containing urea or (NH₄)₂HPO₄, while low or non-significant correlations resulted from NH₄NO₃ treatments. Treatments containing (NH₄)₂HPO₄ and MCP yielded soil solution P concentrations as high as 1000 parts/million. Urea combined with (NH₄)₂HPO₄ or MCP drastically reduced solution P concentrations.     

Effect of sodium,potassium, magnesium,and calcium salt cations on pH,proteolysis, organic acids,and microbial populations during storage of full-fat Cheddar cheese

Sodium reduction in cheese can assist in reducing overall dietary Na intake, yet saltiness is an important aspect of cheese flavor. Our objective was to evaluate the effect of partial substitution of Na with K on survival of lactic acid bacteria (LAB) and nonstarter LAB (NSLAB), pH, organic acid production, and extent of proteolysis as water-soluble nitrogen (WSN) and protein profiles using urea-PAGE, in Cheddar cheese during 9 mo of storage. Seven Cheddar cheeses with molar salt contents equivalent to 1.7% salt but with different ratios of Na, K, Ca, and Mg cations were manufactured as well as a low-salt cheese with 0.7% salt. The 1.7% salt cheeses had a mean composition of 352 g of moisture/kg, 259 g of protein/kg and 50% fat-on-dry-basis, and 17.5 g of salt/kg (measured as Cl⁻). After salting, a faster initial decrease in cheese pH occurred with low salt or K substitution and it remained lower throughout storage. No difference in intact casein levels or percentage WSN levels between the various cheeses was observed, with the percentage WSN increasing from 5% at d 1 to 25% at 9 mo. A greater decrease in intact α_s1-casein than β-casein was detected, and the ratio of α_s1-casein (f121–199) to α_s1-casein could be used as an index of ripening. Typical changes in bacteria microflora occurred during storage, with lactococci decreasing gradually and NSLAB increasing. Lowering the Na content, even with K replacement, extended the crossover time when NSLAB became dominant. The crossover time was 4.5 mo for the control cheese and was delayed to 5.2, 6.0, 6.1, and 6.2 mo for cheeses with 10, 25, 50, and 75% K substitution. Including 10% Mg or Ca, along with 40% K, further increased crossover time, whereas the longest crossover time (7.3 mo) was for low-salt cheese. By 9 mo, NSLAB levels in all cheeses had increased from initial levels of ≤10² to approximately 10⁶ cfu/g. Lactococci remained at 10⁶ cfu/g in the low-salt cheese even after 9 mo of storage. The propionic acid concentration in the cheese increased when NSLAB numbers were high. Few other trends in organic acid concentration were observed as a function of Na content.     

Yield of white clover and its fixation of nitrogen as influenced by nutritional and soil factors under controlled environment conditions

White clover (Trifolium repens L. cv. Blanca) was grown in 21 UK soils. Yield and N concentration in the herbage (leaf + petiole) were determined at six successive harvests and were related to the supplies of major nutrient elements (as indicated by analysis of the herbage) and to various soil properties. The amount of N₂ fixed was estimated by subtraction of the soil N supply from the total amount in the clover. The results suggest that critical concentrations (i.e. concentrations just less than those required for maximum growth) of K, Ca and S in the leaf + petiole after 4 weeks regrowth were approximately 1.4%, 1.3% and <0.16% respectively. The relationship between herbage yield and concentration of N suggests a critical concentration in leaf + petiole of about 3.5% N; lower values probably reflect sub-optimum rates of N₂ fixation and higher values, a restriction of clover growth per se. A reduction in herbage yield attributable to deficiency of K and/or Ca appeared to occur on some soils at harvests 5 and 6, but for any one soil, yield changed little between harvests 2 and 4 inclusive. Differences in herbage yield and in the amount of N₂ fixed over this period were, therefore, examined in relation to various soil properties. Significant positive correlations were obtained between herbage yield and contents of clay, organic matter, water content at 100 cm tension and cation exchange capacity. The amount of N₂ fixed was less closely correlated than was herbage yield with these soil properties.     

原子吸收光谱法测定辣椒及辣椒食品中的微量元素

应用火焰原子吸收光谱法对辣椒及辣椒食品中的Cu、Na、Fe、K、Sr、Mg、Ca、Mn、Zn等9种微量元素的含量进行测定分析。结果显示:Cu、Na、Fe、K、Sr、Mg、Ca、Mn、Zn的标准曲线相关系数为0.9999、0.9820、0.9997、0.9927、0.9982、0.9965、0.9991、1.0000和0.9985;辣椒及辣椒食品中均能检出这9种微量元素,其中辣椒籽中的Cu、Mg、Mn、Zn含量很高;制成辣椒食品后,Na含量大幅度增加,而相对于其他香辣酱,鲜食辣椒酱Na含量最低;辣椒制成辣椒食品后部分微量元素富集(如Cu、Na、Fe、Ca等)比鲜冻辣椒中微量元素含量高。      

Differentiation of milks and cheeses according to species based on the mineral content

Summary The mineral composition of 113 samples of ewes', cows', and goats' milk and 68 samples of different types of pure-milk cheeses made from the milks of these species was analysed. Stepwise discriminant analysis of the milk samples yielded the variables K/Mg, Na/Ca, Zn, Cu/Zn, and Cu/Na as the most useful in differentiating the samples, achieving correct classification in 98.2% of cases. The most useful variables for the cheese samples were Fe/K, Na/Ca, Zn/Cu, Na/Mg, and Zn, which yielded correct classification in 97.1% of cases. The three goat's milk cheeses were successfully distinguished using the variables K/Zn, Fe/Cu, and P.

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Unterscheidung zwischen verschiedenen Milch- und Käsesorten anhand ihrer Mineralstoff-Zusammensetzung

Zusammenfassung An 113 Milchproben und 68 mit Schafmilch, Kuhmilch und Ziegenmilch hergestellten Käseproben wurde die Mineralstoff-Zusammensetzung analysiert. Die Anwendung der schrittweisen Diskriminatoriusanalyse bei den Milchproben ergab die Auswahl der Veränderlichen K/Mg, Na/Ca, Zn, Cu/Zn und Cu/Na als beste Unterschiedlichkeitsparameter mit einer zu 98,2% einwandfreien Klassifizierung. Die bei Käse ausgewählten Veränderlichen waren Fe/K, Na/Ca, Zn/Cu, Na/Mg und Zn mit einer zu 97,1% einwandfreien Klassifizierung. Die Unterscheidung zwischen den 3 geprüften Ziegenmilch-Käsesorten wurde durch die Veränderlichen K/Zn, Fe/Cu und P ermöglicht.

     

Calcium, magnesium, manganese, sodium and potassium variations in Manchego-type cheese during ripening

Changes in the contents of calcium (Ca), magnesium (Mg), manganese (Mn), sodium (Na) and potassium (K) during the ripening of a Manchego-type cheese during storage at temperatures below 10°C were studied over a period of six months. The determinations were performed by atomic absorption spectrophotometry. A two-factor variance analysis showed the existence of statistically significant differences (p < 0·001) in the contents of Ca, Mg, Mn, Na and K between different portions and over a period of time, when the concentrations were considered both on a fresh-weight and a dry-weight basis. However, certain differences in the formed groups according to time were observed using a Scheffe homogeneity test (p < 0·05), depending on whether the mineral content was expressed on a fresh-weight or on a dry-weight basis. The daily intake estimates calculated for the five elements were 47 mg/day for Ca, 2 mg/day for Mg, 2μg/day for Mn, 71 mg/day for Na and 8 mg/day for K in Manchego-type cheese ripened for 6 months.