Inulin effects on bioavailability of soy isoflavones and their calcium absorption enhancing ability

The effect of inulin on isoflavone absorption and the effect of isoflavones and synergy with inulin on calcium absorption in rats was investigated. Rats (n = 48) were divided into three groups and fed inulin (50 mg/g), isoflavone (8 mg/g) or inulin + isoflavone (50 mg/g + 8 mg/g) diets for 21 days. After a 2-h fast, rats were given (45)Ca orally or intraperitoneally, together with 25 mg of calcium as calcium acetate. Blood and femurs were collected 4 days later. Sera were analyzed for isoflavones using HPLC-MS, femurs for (45)Ca by beta-scintillation counting, and total femoral calcium by atomic absorption spectroscopy. Both groups fed isoflavones had similar and significantly higher weight-adjusted total femoral calcium content compared to the inulin-fed group (p < 0.0001). (45)Ca absorption was significantly higher (p < 0.01) when isoflavones were added to the diet, and serum equol was significantly lower (p < 0.01) when inulin was added to the diet containing isoflavones. We conclude that isoflavones enhance calcium absorption, without synergy from inulin, and that inulin decreases equol production.     

Ingestion of water-soluble soybean fiber prevents osteopenia and hypercholesterolemia induced by ovariectomy in rats

This study examined the effects of feeding water-soluble soybean fiber (WSSF), a highly fermentable dietary fiber with low viscosity, on intestinal calcium (Ca) absorption, bone mineral content, and serum total cholesterol levels using female Sprague-Dawley rats (5 weeks old) with or without ovariectomy (OVX). The rats in each group were fed a WSSF (50 g/kg of diet) or WSSF-free diet for 4 weeks. Ca absorption was higher in OVX rats fed the WSSF diet than in OVX rats fed the WSSF-free diet. Femoral Ca content in both sham and OVX rats fed the WSSF diet was higher than that in rats fed the WSSF-free diet. The serum total cholesterol levels were elevated after OVX compared with that in the sham rats, and this elevation was prevented by the WSSF diet. In conclusion, ingestion of WSSF prevented osteopenia and hypercholesterolemia induced by ovariectomy in rats.     

Dietary fibers from mushroom sclerotia. 4. In vivo mineral absorption using ovariectomized rat model

The effect of three novel dietary fibers (DFs) prepared from mushroom sclerotia, namely, Pleurotus tuber-regium, Polyporus rhinocerus, and Wolfiporia cocos, on calcium and magnesium absorption was evaluated in ovariectomized (OVX) rats fed with sclerotial DF based and low Ca (0.3%) diets for 14 days. The animals in the W. cocos DF diet group possessed significantly (p < 0.05) higher levels of cecal total short-chain fatty acids (204 mumol/g of cecal content) and had an acidic pH (5.88) in their cecum when compared with those of the cellulose control group. Such an acidic environment was found to promote the ionization of the unabsorbed Ca and Mg in their cecum, which in turn significantly (p < 0.05) increased the concentrations of cecal soluble Ca (2.56-fold) and Mg (1.22-fold). Besides, the apparent Ca and Mg absorptions of the W. cocos DF group were also significantly (p < 0.05) enhanced (Ca, 16.5%; Mg, 15.3%) together with significantly (p < 0.05) higher serum Ca (3.61 mmol/L) and Mg (1.07 mmol/L) levels when compared with those of the cellulose control group. These data suggest that ingestion of W. cocos DF could improve the overall Ca and Mg absorptions of the OVX rats fed a low Ca diet. The potential use of sclerotial DFs as a functional food ingredient for enhancing mineral absorption is also discussed.     

Utilization of Calcium in Breads Highly Fortified with Calcium as Calcium Carbonate or as Dairy Calcium

White pan breads were prepared with flour highly fortified with calcium (Ca), using Ca carbonate (Ca, 38.8%) or a high Ca whey powder (Ca, 5.6%) as the Ca source; bread was also prepared using Ca carbonate plus lactose. Ca was added to flour at 924 mg/100 g of flour, a level 4.4 times higher than specified under the U.S. enrichment standards. Breads were dried and finely ground to prepare test diets (Ca, 0.5%) which were then fed to growing rats for four weeks (growth phase) or eight weeks (approaching maturity). At either interval, femur ash content, femur Ca content, femur strength, or Ca absorption values did not differ significantly among groups fed breads fortified either with Ca carbonate, Ca carbonate + lactose, or whey. Thus, breads can be highly fortified with Ca carbonate to be labeled as “high” in Ca, and this Ca may be as well absorbed and utilized as dairy Ca.     

Absorption of calcium fumarate salts is equivalent to other calcium salts when measured in the rat model

Calcium absorption from fumarate salts (calcium fumarate and calcium malate fumarate), which have recently been considered for use as sources for food and beverage enrichment, was compared to that from calcium citrate malate, calcium citrate, and calcium carbonate. Salts were instrinsically labeled with 45Ca and orally administered to Sprague-Dawley rats. Fractional absorption of calcium from each salt was determined using the femur uptake model. Fractional absorption from the five salts (0.30-0.27) was not significantly different (p > 0.05). Thus, when measured in the rat model, calcium from calcium fumarate and calcium malate fumarate is absorbed equally well as compared to other salts, which are common calcium sources in many foods, beverages, and supplements.     

Calcium absorption from three salts and CaSO(4)-fortified bread in premenopausal women

Two studies were conducted to measure calcium absorption from calcium sulfate fortified bread and three salts (calcium lactate, calcium carbonate, and calcium sulfate) in healthy premenopausal women using a crossover design. In study I, calcium fractional absorption levels from the three salts labeled with a stable isotope, 44Ca, were not significantly different (0.039-0.47) as determined by the fecal recovery method. In a second study, absorption of 45Ca from CaSO(4)-fortified labeled bread or labeled milk was measured in serum exactly 5 h postingestion. Fractional calcium absorption was slightly but significantly greater from fortified bread than from milk (mean within subject difference = 0.0675 +/- 0.016). Calcium sulfate is a bioavailable fortificant for white bread that compares favorably with milk and two other salts.     

花生根系钙素吸收特性研究

运用电子探针、45Ca示踪及水培方法研究花生根系钙素吸收特性,结果表明花生根伸长区与成熟区均可吸钙,二者吸钙量分别占吸钙总量的28.9％～34.7％和71.1％～65.3％。在供钙浓度为0～0.5nmol/L范围,根系钙素吸收符合Michaelis-Menten酶动力学模型。此时其完全受代谢控制,完整根Km值为0.0549mmol/L、Fmax为3.81nmol/(cmh);断离根Km为0.0534mmol/L、Fmax为3.79nmol/(cm.h)。此后随供钙浓度增加,其受非代谢因素影响越大。供钙浓度为2.0mmol/L时,代谢因素对吸钙总量的贡献为63.2％,而非代谢因素的贡献为36.8％。     

Effect of lowering nutrient solution concentration at night on leaf calcium levels and the incidence of tipburn in lettuce (Var. Gloria)

Butterhead lettuce (var. Gloria) were grown in an evaporatively cooled glasshouse using the nutrient film technique (NFT). During the day all plants received a complete nutrient solution (EC 2 dS/m). Treatments were imposed at night and included: complete nutrient solution (control); tap water (EC 0.19 dS/m); and calcium nitrate solutions containing either 100 mg Ca/L (EC 0.80 dS/m), or 200 mg Ca/L (EC 1.45 dS/m).

Tipburn occurred in the control and its incidence was reduced by the other treatments. This effect was associated with an increase in the concentration of calcium in new leaves, except in the water treatment. The night treatments did not affect the fresh weight of mature lettuce.

Circulation of either water or calcium nitrate (100 mg Ca/L) at night may, therefore, be a commercially acceptable means of reducing tipburn losses in lettuce crops grown using hydroponics.     

花生荚果钙素吸收机制研究

采用45Ca微观放射自显影、电子探针及特异性抑制剂研究花生荚果钙素吸收机制,结果表明,Ca2+是通过主动吸收由外界进入细胞质中,并以共质体途径在组织和细胞间运输,外果皮的周皮层和中果皮的纤维细胞层对Ca2+质外体运输有一定阻碍作用。钙通道抑制剂与ATP酶特异性抑制剂处理,中果皮和内果皮的薄壁细胞内未见45Ca显影,大量45Ca出现在周皮层,仅微量的45Ca到达中果皮细胞间隙和纤维细胞层质外体空间。电子探针的结果也可看出高钙峰出现在周皮层,而对照处理荚果整个组织的共质体和质外体均有45a的显影,且由外果皮向内,组织中的钙呈逆浓度梯度分布。2,4二硝基酸可抑制荚果钙素吸收速率,其抑制率达7092％。荚果钙素吸收动力学的结果表明,当Ca2+浓度为0-0.5mmol/L时,其吸收速率符合Michaelis-Menten酶动力学模型,Km值为0.0135mmol/L,Fmax为13210-4.mol/(cm2h);而当Ca2+浓度为1-5mmol/L范围时,其表现出复杂的吸收特征,此时Km和Fmax均无法得出明确的数值;供钙浓度为0.5-2.0mmol/L时,荚果干重及果仁干重与吸钙量均可达到最大并趋于稳定。     

用~(45)Ca示踪法研究小麦对钙的吸收及其在土壤中的移动

本试验利用~45Ca示踪法,研究了小麦对钙的吸收和运转。结果表明,用0.1％~45CaCl_2浸种,~45Ca能被吸入籽粒内,并且48小时的吸收量比24小时的吸收量高1倍以上。涂抹试验表明,无论苗期还是后期,叶片涂抹~45Ca均能被叶片吸收,吸收的钙能转移到邻近的叶片。土壤引入的钙可以被根系吸收并能转移到地上部。钙在石灰性土壤中移动性很差,在淋溶条件下,1周时间仅有0.4％的钙下移1cm。PEG胁迫试验表明,干旱条件影响小麦幼苗对钙的吸收,在一定范围内,随胁迫程度增大,吸收钙量下降,但当溶液水势低于—0.18MPa时,小麦对钙的吸收量又逐渐增高。     

Increase in Bone Calcification in Young Rats Fed Breads Highly Fortified with Calcium

Breads were prepared with flour fortified with calcium (Ca) at four levels: 211 (U.S. enrichment standard), 446, 924, and 1,412 mg/100 g of flour. Corresponding diets prepared with these breads and fed to growing rats for four weeks provided 25 (diet A), 50 (diet B), 100 (diet C), and 150% (diet D) of their Ca requirement. After four weeks, the Ca content of the femurs of these rats had increased significantly as Ca in the diet increased up to 100% of requirement but not beyond. The increase in femur strength was significant only between diet A and diet B. Apparent Ca absorption increased as Ca in the diet increased, but Ca absorbed from diet D was not retained any better than that absorbed from diet C. Overall, the data suggested that Ca in highly fortified breads was well absorbed and retained, and that the rats' Ca status early in life was greatly improved. Flour fortified with Ca up to the 924-mg level (4.4× the mandated enrichment level) had no adverse effect on bread quality. These breads can be labeled a “good source of ” or “high in” Ca.     

Bioavailability of Calcium in Breads Fortified with Different Calcium Sources

This study used young rats as the test model to examine the relative bioavailability (RB) of calcium (Ca) in breads fortified with five different Ca sources. These sources included two inorganic (Ca carbonate and Ca sulfate) and two organic (Ca citrate and Ca lactate) Ca sources, and a brandname Ca supplement. RB was assessed based on rats' femur Ca content and Ca absorption data. No differences of any physiological significance were observed in RB of Ca among the five sources tested. Compared to Ca carbonate (bioavailability arbitrarily set at 100%), RB of Ca in Ca sulfate was 105%, in Ca citrate 103%, in Ca lactate 102%, and in the Ca supplement 102%. This suggests that foods fortified with Ca carbonate or Ca sulfate, which are commonly used for this purpose, may be as good a source of utilizable Ca as more expensive Ca sources such as prescribed or nonprescribed Ca supplements.     

施氮水平对富士苹果果实钙形态及品质的影响

[目的]钙是影响苹果果实品质最重要的元素之一,施氮量影响树体对钙的吸收.探究不同施氮量对果实品质、钙形态以及二者之间的关系的影响,以期为通过科学施肥改善苹果果实品质提供参考.[方法]本研究选择5年生盆栽富士(基砧为组培山定子,中间砧为SH38)为试材,共设6个施氮水平:0(N0)、50(N50)、100(N100)、2...     

Direct and selective flow-injection method for the simultaneous spectrophotometric determination of calcium and magnesium in red and white wines using online dilution based on "Zone Sampling".

The present work reports a selective and simple flow injection method for the direct and simultaneous determination of calcium and magnesium ions in red, rose, and white wines. Both ions react with methylthymol blue (MTB) at a strongly basic medium to form colored complexes that are monitored spectrophotometrically (lambda(max) = 610 nm). The simultaneous determination is achieved by online masking of magnesium by 8-hydroxyquinoline (8-HQ). Incorporating an online dilution mode based on the "zone sampling" technique in the FI system, the determination of both analytes was achieved without any pretreatment of the samples, in the range 0-350 mg L(-1) and 0-200 mg L(-1) for Ca(II) and Mg(II), respectively. The 3 sigma detection limits were quite satisfactory (2.1 and 1.8 mg L(-1) for Ca(II) and Mg(II) respectively), and the precision was 1.2% (at a mixture of 100.0 mg L(-1) Ca(II) + 100.0 mg L(-1) Mg(II), n = 12). A detailed study of interferences proved that the proposed method is highly selective. The application of the method to the direct analysis of red, rose, and white wines yielded excellent results compared with those obtained by using FAAS as a reference method (e(r) < 2.8%).     

Galactooligosaccharides improve mineral absorption and bone properties in growing rats through gut fermentation

Galactooligosaccharides (GOS), prebiotic nondigestible oligosaccharides derived from lactose, have the potential for improving mineral balance and bone properties. This study examined the dose-response effect of GOS supplementation on calcium and magnesium absorption, mineral retention, bone properties, and gut microbiota in growing rats. Seventy-five 4-week-old male Sprague-Dawley rats were randomized into one of five treatment groups (n = 15/group) and fed a diet containing 0, 2, 4, 6, or 8% GOS by weight for 8 weeks. Dietary GOS significantly decreased cecal pH and increased cecal wall weight and content weight in a dose-dependent manner (p < 0.0001). Fingerprint patterns of the 16S rRNA gene PCR-DGGE from fecal DNA indicated the variance of bacterial community structure, which was primarily explained by GOS treatments (p = 0.0001). Quantitative PCR of the samples revealed an increase in the relative proportion of bifidobacteria with GOS (p = 0.0001). Net calcium absorption was increased in a dose-response manner (p < 0.01) with GOS supplementation. Dietary GOS also increased (p < 0.02) net magnesium absorption, femur ??Ca uptake, calcium and magnesium retention, and femur and tibia breaking strength. Distal femur total and trabecular volumetric bone mineral density (vBMD) and area and proximal tibia vBMD increased (p < 0.02) with GOS supplementation. Trabecular-rich bones, that is, those that rapidly turn over, were most benefited. Regression modeling showed that GOS benefited calcium and magnesium utilization and vBMD through decreased cecal pH, increased cecal wall and content weight, and increased proportion of bifidobacteria.     

Effect of Sample Preparation Methods on Analytical Values of Some Micro‐ and Secondary Nutrients in Plant Tissues

Abstract: Plant tissues of rice and wheat crops (n = 5) collected at harvest time were wet‐ashed in di‐acid mixture [analytical‐grade nitric acid (HNO₃)–perchloric acid (HClO₄), 3:1, v/v] on a sand bath at 200 °C or dry‐ashed in a muffle furnace at 550 °C for 3 h in triplicate. The samples were analyzed for calcium (Ca), iron (Fe), and molybdenum (Mo) using double‐beam atomic absorption spectrophotometry (GBC‐Avanta ∑ model) and for boron (B) by colorimetry (UV‐VIS spectrophotometer, ECIL‐GS 5705 model) using Azomethine‐H procedure. As per the paired t‐test, both wet‐ashing and dry‐ashing procedures resulted in statistically similar analytical values for B, Ca, Fe, and Mo. However, the mean coefficients of variation were higher with the wet‐ashing procedure (6.19 to 9.64%) as compared to the dry‐ashing procedure (2.14 to 3.45%). The dry‐ashing procedure was found to be the best for routine chemical analysis of B and Mo in plant samples.     

钙对大豆幼苗镍毒害的缓解效应及对抗氧化酶活性的影响

采用盆栽方法,研究了镍毒害条件下外源钙对大豆镍毒害的缓解效应以及对其叶片组织中超氧化物歧化酶(SOD)、过氧化氢酶(CAT)、过氧化物酶(POD)和抗坏血酸过氧化物酶(APX)活性的影响,以探讨钙缓解植物镍毒性的生理机制.研究结果表明:Ni2+60 mg/kg添加量对大豆幼苗生长表现出明显的抑制作用,但是当加入不同钙量后,大豆的镍毒害症状得到不同程度的缓解,Ca2+ 200 mg/kg处理的缓解作用好于Ca2+ 100 mg/kg.与不施镍处理相比,单施Ni2 60 mg/kg处理的大豆叶片组织SOD、CAT和APX活性明显下降,而POD活性明显上升.当配施Ca2以后,大豆叶片组织中SOD、CAT、POD和APX活性明显提高,且Ca2+ 200 mg/kg处理的上升程度比Ca2+ 100 mg/kg处理的大.因此,Ca2+是通过提高叶片组织抗氧化酶活性,增强活性氧清除能力,而使大豆的镍中毒症状得到缓解,这是Ca2+减轻大豆镍毒害的生理机制之一.     

Spectrophotometric method for hydroxymethylfurfural in honey.

A new method is described for hydroxymethylfurfural (HMF) in honey; accuracy and precision are improved over the most used optical and chemical methods. With a clarified honey solution containing 0.1% sodium bisulfite as reference and a similar solution without bisulfite as sample, a difference spectrum is obtained which represents only the HMF in the sample, without the interfering absorption of the honey. The average recovery was 97.5% for 24 additions to honey of 0.8--40 mg HMF/100 g. Forty honey samples ranging from 0 to 40 mg/100 g were analyzed by 3 methods with the following average results: Winkler optical method, 7.25; Winkler chemical method, 4.83; and new bisulfite method, 5.05 mg HMF/100 g honey. Values by the latter 2 methods did not differ at the P = 0.05 significance level.     

小麦根质膜微囊的制备及水分胁迫对~(45)Ca~(2+)转运活性的影响

利用蔗糖密度梯度离心法制备小麦根质膜微囊,研究结果表明,郑引１号小麦根质膜Ｈ＾＋－ＡＴＰａｓｅ潜在活性为２４％,内翻外型质膜囊泡占７６％,－１．０ＭＰａ ＰＥＧ胁迫处理２４ｈ,两种定向的小麦根质膜Ｃａ６２＋－ＡＴＰａｓｅ活性均增加,正常水分条件下和ＰＥＧ胁迫处理后,ＥＧＴＡ对该酶活性抑制率分别为６２％和５３％,内翻外型质膜微囊对放射性核素＾４５Ｃａ＾２＋的转运量分别为２２．０９ｎｍｏｌ／ｍｇ ｐｒ     

Iron tissue storage and hemoglobin levels of deficient rats repleted with iron bound to the caseinophosphopeptide 1-25 of beta-casein.

Caseinophosphopeptides (CPP) issued from enzyme digestion of caseins bind cations and keep them soluble in the digestive tract. They could be used as ligands to improve iron (Fe) bioavailability. Fe-deficient young rats were repleted with Fe (40 or 200 mg/kg of diet) bound either to the beta-CN (1-25) of beta-casein or to whole beta-casein or as FeSO(4). A control pair-fed group was given 200 mg of Fe (FeSO(4))/kg of diet for 6 weeks. After repletion, hemoglobin concentration of the control group was reached only by the ) animals fed 200 mg of Fe/kg; beta-CN (1-25) bound Fe (40 and 200 mg) produced higher Fe liver and spleen stores than FeSO(4). Binding Fe to the whole, nonhydrolyzed beta-casein gave results intermediate between the other experimental groups. Binding Fe to phosphoserine residues of low molecular weight CPP improved its ability to cure anemia and to restore iron tissue stores, as compared to Fe bound to the whole casein and to inorganic salts.