高钙豆乳的钙吸收试验研究

通过动物试验检验发芽大豆制得的高钙豆乳的吸收效果.挑选40只平均体重18g～22g断乳小鼠分成5组,每组8只,喂饲低钙饲料的同时每天灌服不同含量的豆乳,饮用去离子水,在饲养15 d时做3 d钙代谢试验,测定指标有小鼠的最终体重、钙吸收率、骨钙含量、血清钙含量、股骨指数、股骨重量.喂饲发芽大豆制得的高钙豆乳的小鼠体重增长率为86.5%,钙吸收率为84.66%,股骨重量、股骨指数、股骨钙含量、血清钙含量与对照组比差异显著.     

钙与补钙

就目前我国人口普遍存在的缺钙问题提出了科学补钙的方法,并介绍了钙的生理功能、吸收机理及影响因素、常用钙制剂等。     

钙的生物利用度与多肽螯合钙研究进展

钙是人体内十分重要的营养元素，对维持人体健康起到了至关重要的作用。小肠是钙吸收的主要部位，食物中的钙经胃酸溶解为离子形式后在微碱性的肠道环境内可能会形成沉淀，导致钙的吸收下降和生物利用度降低。而长期钙摄入不足则会导致佝偻病、骨质疏松症等一系列骨代谢疾病。因此，选择能够提供高可溶性和生物利用度的钙的食物或补充剂十分重要。部分有机钙盐如葡萄糖酸钙、柠檬酸钙等可以在肠道中形成过饱和溶液从而增强钙的吸收。此外，多肽螯合钙也被证实有非常好的钙吸收率和生物利用度，可以作为新型的钙补充剂。本文综述了食物基质成分对钙吸收和生物利用度的影响，并对部分有机钙盐和多肽螯合钙的促钙吸收机理进行了总结，旨在为钙的吸收与钙补充剂的研发提供新的思路。     

机体钙营养与合理补钙

钙是人体中含量最多的矿物质元素,其缺乏会引起机体发生一系列病变,综述钙的生理功能、钙在体内的调节、钙的代谢、影响钙吸收的因素、我国钙缺乏现状及改善钙缺乏的方法.     

理想的钙营养强化剂—食用钙

本品为广东盖世宝有限公司独家生产的中国专利产品，是国家批准的钙营养强化剂，属国家级重点新产品，含钙２３％以上，溶解度３８．５克，溶液中性，导电强、易磁化、钙为离子态易被肠道直接吸收，补钙效果好，无便秘等副作用，可加入汤菜面饭及开水等饮料中食用，更适用于工业制钙保健食品。     

酱油及钙强化酱油中钙的测定

钙是食物中重要的矿物质。食物中钙含量的测定,主要有高锰酸钾法、原子吸收法和ＥＤＴＡ法。由于食物同时存在镁、铁、锌等离子,用高锰酸钾法测定钙,测定结果容易偏离,而且测定过程较为繁锁;原子吸收法的选择性和灵敏度高,但样品需经灰化而且需要价格昂贵的专用设备...     

钙营养缺乏及合理补钙

钙是人体必需的矿物元素,适量的钙供给对人体健康至关重要,缺钙会引起儿童佝偻病、中老年骨质疏松、骨软化等疾病。我国居民膳食中钙摄入严重不足,仅占供给量标准的５０％左右。据１９９２年全国营养调查的结果表明,钙是中国居民膳食中缺乏最明显的营养素。近年来,随着人们对钙摄入量与儿童、青少年骨质发育和成人骨健康关系认识的不断深入,对补钙食品和钙制剂的需求日益增加,补钙成为人们关注的热点。 一、钙的主要生物学功能 钙是人体中含量最多的无机元素,约占体重的ｌ．５０～２．００。人体总钙含量达１３００ｇ,其中９９％以…     

乳钙和干酪素磷肽的钙强化功能

<正> 钙是非常重要的营养素,能够预防骨质疏松症。但是,据有关研究显示,全球各地尤其是亚洲地区的居民,普遍存在缺钙的情况,大大影响了其国民的身体素质。有鉴于此,营养权威专家正积极讨论和复审膳食钙的需求量(RDA),并制定新的推荐钙摄入量(RDI),例如,美国最近就提高了其推荐钙摄入量的新标准,其他国家也将仿效这种做法。 为人体补充钙的有效方法,是在我们日常进食的食品中进行钙强化。提取自牛奶的乳钙,具有优良的感官性质,而且极具营养性,是理想的天然食品级钙源。另一方面,营养科学界普遍认为,钙源的溶解性决定了钙能否良好地被人体吸收,干     

影响微生物富钙因素的研究

用微生物富集钙,氯化钙是一种较好的钙源,其钙浓度以Ca2 计为0.6%时,有利于富钙微生物菌丝体的生长及对钙的富集;食用丝状真菌F2生物量大、富钙率高,且含有较高的蛋白质、维生素和各类氨基酸,是一种较理想的富钙菌种;生物钙制剂含有易被人体吸收的氨基酸钙,可作为目前钙制剂的换代产品。     

富钙啤酒的研制

介绍了富钙啤酒的研制过程，所研制成功的富钙啤酒其钙离子含量达到110mg／L，富钙啤酒中含有人体所需的离子钙。     

蛋壳中碳酸钙转化成柠檬酸钙的研究

蛋壳经预处理和粉碎后,通过添加柠檬酸直接反应制备柠檬酸钙。通过单因素和正交试验分别考察了反应温度、蛋壳粉粒度和柠檬酸过量程度对蛋壳制备柠檬酸钙产品纯度和转化率的影响,结果表明在反应温度为60℃、蛋壳粉过200目筛、柠檬酸过量15%条件下得到的柠檬酸酸钙产品的纯度能达到95%以上,柠檬酸钙产率可以达到98%。     

含乳(钙奶)饮料中钙含量的测定

目前对含乳饮料中钙含量的测定一般采用GB12398-90<食物中钙的测定方法>,有原子吸收分光光度法和EDTA滴定法.     

Intravenous calcium infusion in a calving protocol disrupts calcium homeostasis compared with an oral calcium supplement

Hypocalcemia is a common postpartum condition in dairy cows, which negatively affects health and production. Intravenous Ca infusions are commonly included in calving protocols to prevent or mitigate the effect of hypocalcemia in multiparous cows. Thus, we sought to contrast the effect of intravenous Ca infusion against voluntary oral Ca intake on Ca metabolism. Serum total Ca (tCa) and whole-blood ionized Ca (iCa) were monitored in 24 multiparous Holstein cows after parturition. Precalving diets were formulated with a positive dietary cation-anion difference of 172 mEq/kg of DM and contained 4.1 g of Ca/kg of DM. At parturition, cows were blocked by calving sequence and calcemic status as either normocalcemic (cutoff threshold of iCa ≥1.10 mmol/L) or hypocalcemic (cutoff threshold of iCa <1.10 mmol/L). Cows in each block were randomly assigned to 1 of 2 treatments: either an oral source of Ca (Ca-Oral; n = 12) or an intravenous source of Ca (Ca-IV; n = 12). Cows in the Ca-Oral group were offered a 20-L commercial Ca suspension (48 g of Ca) for voluntary consumption. The supplement contained Ca carbonate, Ca formate, Ca propionate, and other minerals and vitamins (Farm-O-San Reviva, Trouw Nutrition, Amersfoort, the Netherlands). Cows in the Ca-IV group received a 450-mL intravenous Ca solution (13 g of Ca) that contained 298 mg/mL of Ca gluconate, 33 mg/mL of magnesium chloride, and 82 mg/mL of boric acid (AmosCAL, Kommer-Biopharm BV, Heiloo, the Netherlands). Both treatments were initiated within 25 ± 10 min after calving. The oral Ca suspension was offered to cows in a 25-L bucket and was available for 10 min. All cows in the Ca-Oral group voluntarily consumed the entire 20 L of the Ca suspension within 5 min. Blood samples for Ca analyses were collected at 0 (before treatment initiation), 1, 3, 10, and 18 h relative to treatment, and at 0700 and 1900 h for the next 2 consecutive days, to represent the 24-, 36-, 48-, and 60-h sampling time points. In Ca-IV cows, both iCa and tCa concentrations peaked at 1 h (1.54 mmol/L for iCa and 2.85 mmol/L for tCa) and declined to a nadir at 24 h following treatment initiation (0.94 mmol/L for iCa and 1.74 mmol/L for tCa). Although whole-blood iCa and serum tCa were higher at 1 and 3 h in Ca-IV cows, concentrations of iCa were greater for Ca-Oral cows at 18, 24, and 36 h and for tCa at 24 and 36 h. Our data indicate that intravenous Ca infusion immediately induced a state of hypercalcemia followed by lower whole-blood iCa and serum tCa concentrations 24 h later compared with oral Ca.     

Effect of calcium carbonate,calcium citrate,tricalcium phosphate,calcium gluconate and calcium lactate on some physicochemical properties of soymilk

Soymilk fortified with 25 mm Ca (Ca carbonate, Ca citrate, triCa phosphate, Ca gluconate or Ca lactate) was compared with the properties of unfortified soymilk (control). Calcium carbonate, Ca citrate and triCa phosphate did not significantly affect [Ca²⁺], absolute viscosity and particle size of soymilk, but Ca gluconate and Ca lactate significantly increased these properties. The pH of soymilk was significantly increased by adding Ca carbonate but significantly reduced by adding Ca gluconate and Ca lactate. Dry sediment of soymilk increased significantly with the addition of all Ca salts excluding triCa phosphate. Freezing point depression increased significantly only for Ca gluconate and Ca lactate, mainly owing to their higher solubility.     

微囊乳钙补钙剂的测定研究

微囊乳钙是以乳清为原料,经去除部分蛋白质、乳糖成分后得到乳矿物盐,再采用微胶囊技术包埋制成的高效补钙剂.文中采用扫描电镜、红外光谱仪、X-射线衍射光谱仪、X-射线荧光光谱仪等仪器和方法,测定一种进口的微囊乳钙产品的结构与性质.结果表明,微囊乳钙颗粒表面凹凸,大小不均,粒径在2～100μm-间;主要成分为磷酸钙盐,灰分含量约78.5％～78.9％,蛋白质1.93％,样品可溶于中酸性至强酸性溶液中.     

Effect of calcium and fat intake on calcium metabolism in calves

Ten male Holstein calves were fed diets with or without 5% added animal fat in combination with low and high dietary calcium (.15 or .98%) for 4 wk. After 3 wk, the animals were orally dosed with calcium-45. One week later they were killed and tissue samples taken. Except for lower calcium-45 in bile, added dietary fat had no marked influence on calcium metabolism. Net absorption of calcium-45 (not excreted in feces) ranged from 82% for calves fed low calcium to 53% for those given high calcium. Calcium-45 in bone was substantially higher in calves fed .15% calcium. Tailbone biopsies revealed rapid uptake of calcium-45 with approximately as much incorporated during the 1st d as in the following 6 d. Calcium-45 in blood peaked 24 h following dosing. Calves fed .15% calcium had higher calcium-45 in blood and bile than those receiving .98% calcium. Calcium-45 values in soft tissue were low and did not differ materially among treatments. The decreases in radioactive calcium absorption and bone deposition with higher dietary calcium indicated that variable absorption was a major factor in calcium homeostasis. Added fat did not materially effect calcium metabolism with either low or high dietary calcium.     

硫酸钙在膳食钙中的应用现状及优势

中国式补钙的背后,国内外营养学界普遍建议,通过高钙食物来补充钙,减少补充剂摄入量。通过探讨在膳食中较为常用的硫酸钙、碳酸钙、氯化钙和磷酸钙4种无机钙盐在食品中的应用及其优缺点,最终认为天然、无毒、高性价比的硫酸钙在膳食钙的应用中更胜一筹。     

离子选择性电极法测定味精生产中的钙含量

拟定了以钙离子选择电极为指示电极，饱和甘汞电极为参比电极，EGTA标准溶液为滴定荆的电位滴定法测定味精生产过程中钙含量的分析方法。该方法的测定结果与原子吸收法基本一致，标准偏差在0．018～0．025之间，相对标准偏差在1．00％～2．12％之间，回收率在95．0％～102．3％范围内。     

生物活性肽促钙吸收机制与钙离子通道

近年来,第4代补钙产品——促钙吸收肽(如酪蛋白磷酸肽)的研究已成为热点,其主要是通过钙离子通道发挥促钙吸收作用。钙离子通道是一组跨细胞膜的蛋白质,它控制着Ca~(2+)进入细胞的过程,TRPV6和Cav1.3是钙在肠道跨膜吸收的2种重要钙离子通道。TRPV6是TRPV离子通道家族成员中高选择性的Ca~(2+)转运通道,由钙结合蛋白D9k(Calbindin-D_(9k))和维生素D共同参与调节。Cav1.3在去极化条件下被激活,从而发挥重要的促钙吸收作用,但其不依赖于Calbindin-D_(9k)和维生素D的调控。小肽转运蛋白是一种低亲和力、高容量的协同转运载体,其不仅可以消除氨基酸之间的相互竞争,加速蛋白合成,也可促进动物对矿物质的吸收与利用。本文概述了生物活性肽通过其与2种最常见的钙离子通道(TRPV6、Cav1.3)的作用及小肽转运系统(Pep T1转运)转运,以促进钙的高效吸收,旨在阐明活性肽的高效促钙吸收机制。