影响果胶钙凝胶形成的因素以及果胶钙凝胶应用

果胶钙凝胶具有化学性质稳定、生物相容性好、食用安全等优点,在食品、药品、微生物等领域具有潜在应用价值。文中综述了果胶钙凝胶的形态、结构、安全性,影响其形成因素、应用现状与发展趋势,以期为果胶钙的应用提供理论指导。     

中性高钙液体奶的钙剂筛选及稳定性研究

对中性高钙液体奶生产中不同钙剂和稳定剂对产品稳定性和品质的影响进行了研究。结果表明,以乳钙为钙强化剂,添加量为6g/L,微晶纤维素复配卡拉胶(1∶1)为稳定剂,添加量为3g/L,制备的中性高钙液体奶对热稳定,口感不会明显增稠,钙含量(以钙元素计)可达2.64g/L。     

Cyclic changes in plasma calcium and the calcium homeostatic endocrine system of the postparturient dairy cow

Plasma Ca, P, Mg, parathyroid hormone, and 1,25-dihydroxyvitamin D were measured in blood samples taken daily from d 5 before until d 15 to 30 after calving in 28 aged dairy cows (5 yr or older) and 9 first lactation cows. Subnormal plasma Ca concentrations were defined as being below the lower limit (2.18 mmol/L) of the 99% confidence interval for lactating cows outside the month of calving. A parturient minimum in plasma Ca and P concentrations occurred usually within 24 h after calving in all animals. Plasma mineral changes very similar to those at parturition were observed in 50% of the aged cows at one, two, or even three later occasions during the 1st mo postpartum. Interval between subsequent subnormal Ca minima in these Ca-cycling cows was 7 to 10 d. The function of the Ca regulating endocrine systems appeared adequate. Calcium cycling with increased amplitude could be induced by feeding 200 micrograms/d of 1,25-dihydroxyvitamin D3 for about 5 d around parturition (8 animals). The hypocalcemic episode was more pronounced than in untreated cows, and Ca cycling was traced throughout the 1st mo of lactation. Similar treatment also induced Ca cycling in 4 heifers, whereas 8 untreated heifers showed no tendency to Ca cycling in the postparturient period. The hypothesis is put forward that variations in intestinal Ca absorption induced by 1,25-dihydroxyvitamin D3 are the primary cause of the cyclic changes in plasma Ca postpartum of the aged dairy cow.     

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     

浅谈钙盐和铁盐的生物利用性

<正> 过去几年问,食品和饮料工业界中新产品层出不穷,配料的生产技术也不断得到改进,并推出许多营养强化食品和饮料产品。目前采用矿物质来强化食品和饮料趋势的形成,是由于可以让消费者选择的食品种类始终有限,未能满足人体各项所需,从而影响个人的健康状况,长此以往对人体的各项功     

不同钙补充剂对缺铁性贫血大鼠钙、铁吸收的影响

探讨柠檬酸苹果酸钙(Calcium citrate malate,CCM)、碳酸钙(Calcium carbonate,Ca CO3)、骨钙(Bone calcium,BC)三种常用钙剂与富马酸亚铁(Ferrous fumarate,FF)合用对钙、铁吸收的影响,以及三种钙剂的生物利用度,为消费者选择合适的钙剂提供实验依据。建立大鼠缺铁性贫血模型,通过检测大鼠血红蛋白(Hemoglobin,Hb)和血清铁(Serum iron concentration,SFe)含量,观察三种钙源与铁制剂合用对钙、铁吸收的影响;通过药代动力学考察血清降钙素(Calcitonin,CT)含量,评估三种钙剂的生物利用度。实验结果表明CCM/FF组与Ca CO3/FF组和BC/FF组相比,CCM/FF组合给药3 d后即能显著升高缺铁性贫血大鼠血红蛋白含量,其血红蛋白含量给药14 d极显著高于Ca CO3/FF组(p0.01);CCM/FF组的血清铁含量在给药1 d后即显著高于Ca CO3/FF组(p0.01),说明CCM对铁吸收的抑制作用较小。此外,CCM的降钙素曲线下面积(Area under the curve,AUC)高于Ca CO3及BC,间接反映了CCM吸收率较其它钙剂多。     

合浦珠母贝壳制备碳酸钙、丙酸钙的工艺研究

以合浦珠母贝开珠后的贝壳为原料,研究制备碳酸钙、丙酸钙的工艺技术.通过分析贝壳粉颗粒大小和酸的品种、浓度及用量对酸溶率的影响,结果表明:100目的贝壳粉与4mol/L的盐酸,按固液比为1:20,在40℃酸溶处理2h,酸溶率可达到99%,该酸溶液与Na2CO3溶液的体积比为9:5时,碳酸钙得率最高;利用L6(34)正交实验优化丙酸钙工艺,结果表明,最佳工艺条件为碳酸钙与水的比例1:40(W/V),碳酸钙与丙酸比例1:3(W/V),反应温度60℃,反应时间0.5h,丙酸钙产率为86%,产品纯度为83.4%.     

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.     

大豆异黄酮加钙复合剂对卵巢切除大鼠骨密度和骨钙含量的影响

利用卵巢切除大鼠模型 ,研究大豆异黄酮 +钙复合剂对骨密度和骨钙含量的影响。卵巢切除大鼠分为 3个剂量组 ,分别灌胃给予 6 7mg kgBW 大豆异黄酮 +16 7mg kgBW 钙 (低剂量组 )、13 3mg kgBW 大豆异黄酮 +33 3mg kg BW 钙 (中剂量组 )和 4 0 0mg kg BW 大豆异黄酮 +10 0 0mg kgBW钙 (高剂量组 ) ,同时设阴性对照组和假手术组。 12周后测定股骨骨密度 (MBD)、骨矿含量(BMC)和骨钙含量。结果发现假手术组、中剂量组和高剂量组大鼠股骨干骺端BMD、BMC和股骨钙含量显著高于阴性对照组 (P <0 0 5 ) ,表明大豆异黄酮 +钙复合剂能增加卵巢切除大鼠的骨密度 ,对雌激素缺乏所诱发的骨丢失具有抑制作用。     

The equilibria of calcium and phosphate ions with the micellar calcium phosphate in cow's milk.

Calorimetric measurements of the heat of solution of micellar Ca phosphate suggest that this material more closely resembles OH-apatite than amorphous Ca phosphate or any other crystalline form. Preliminary computer calculations of the ionic equilibria of milk salt solutions indicate that, over a wide range of pH and temperature, such solutions are supersaturated with respect to OH-apatite and to various other Ca salts under certain conditions.     

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.     

鸡蛋壳中碳酸钙转化制备柠檬酸钙的研究

论述了利用鸡蛋壳制取柠檬酸钙.采用高温煅烧的方法,使蛋壳中所含的CaCO3经高温煅烧后完全分解为CaO,再加入柠檬酸进行中和反应制备柠檬酸钙.实验过程中对高温煅烧分解条件进行了研究探讨,筛选出最佳煅烧分解条件.在中和反应阶段引入正交实验对加水量、不同柠檬酸浓度和用量以及中和反应温度进行了研究探讨,采用综合加权评分法和极差分析法对实验结果进行分析.结果显示最佳中和反应条件为:加水量为50mL,柠檬酸浓度为1 mol/L,柠檬酸用量为35mL,中和反应温度为70℃.最佳中和反应条件下柠檬酸钙的产率为84.36％±0.48％,含量为87.84％±0.51％.     

On the preparation of calcium alginate isotropic gels using water-soluble calcium salts

The introduction of NaCl into the gel-forming system sodium alginate-CaCl₂-H₂O allows to obtain monolithic isotropic calcium alginate gels by use of the method of mechanical mixing of the reagent solutions. To reach the maximum firmness of the 1.5% gel the NaCl concentration of 0.1 M is necessary.     

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。     

钙强化剂和钙强化食品的研究进展

综述了钙吸收机理,钙营养强化剂与钙强化食品的研究现状.     

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。     

钙源的比较和应用

<正> 钙是目前应用于强化食品的主要矿物质含量,它也被列为重要的功能性配料之一。在美国,骨质疏松已被列为仅次于癌症和心脏病的第三大疾病,关于治疗和预防措施的需求也在不断上升。据一篇题为“日本功能性食品和饮料”的报告中,列举出40%以上的饮料、80%以上的干酪产品、60%的乳及乳酸菌饮料,以及45%,的酸奶都经过钙的强化。 鉴于我国居民膳食结构的不均衡,加上奶类产品食用量少,故国民大都出现钙缺乏的现状。目前,人们对“钙”     

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.