直接进样-连续光源火焰原子吸收法测定乳及乳制品中的微量元素

建立了一种用三氯乙酸作沉淀剂沉淀乳及乳制品中的蛋白质、脂肪等物质,滤液直接进样,用连续光源火焰原子吸收光谱仪测定钾,钠,钙,镁,铜,锌6种元素的分析方法.6种元素在1.0～1 600mg/L的添加水平,回收率为90.0%～107.0%,变异系数为1.52%～5.75%.该方法操作简便、测定速度快、结果准确,与国家标准方法比较无显著性差异,适合于乳及乳制品中多种微量元素的快速测定.     

辽宁地区不同来源新鲜牛乳主要营养成分分析

以位于辽宁省东南西北4个不同方位--沈阳、本溪、鞍山、锦州不同来源的新鲜牛乳为研究对象,分析其乳中脂肪含量、非脂乳固体含量、蛋白质含量、酪蛋白含量以及牛乳中不同形态的钙含量,并与相应的鲜牛乳国家标准进行比较。同时,研究鲜牛乳的主要成分在地域之间的差异和成分之间的相关性。结果表明：本实验所抽检的来自辽宁不同地区新鲜牛乳样品中脂肪含量、非脂乳固体含量、蛋白质含量均符合国家标准,但不同地区之间,3项指标的含量存在显著性差异。而牛乳中酪蛋白含量占蛋白质总量的百分率和游离钙占总钙的百分率却相当稳定,其变化范围分别为77.0%～78.5%和64.73%～66.38%。脂肪含量与非脂乳固体含量呈极显著负相关,蛋白质含量与络合钙含量呈极显著正相关关系。     

毛细管电泳法对乳及乳制品中乳源蛋白的测定

采用毛细管电泳方法对乳及乳制品中乳源蛋白成分进行检测.选择聚乙烯醇涂层毛细管,采用柠檬酸缓冲体系,在紫外检测214 nm、分离电压20 kV条件下对乳及乳制品中的α-乳白蛋白(α-La)、β-乳球蛋白(β3-Lg)、α-酪蛋白(α-CN)、β-酪蛋白(β-N)和k-酪蛋白(k-N)进行分离测定.五种蛋白线性良好,线性相关系数均大于0.997 8,各蛋白峰面积的相对标准偏差为1.76％～3.28％,加标回收率范围为88.1％～110.8％.应用该方法对液态奶、酸奶及奶粉中的乳源蛋白进行测定.本法准确、简便、易行,适于测定液态奶、酸奶、奶粉中蛋白质的检测.     

一种快速无损鉴定合成立方氧化锆的方法

对于体积很小的样品,常规仪器无法检测,本文利用X-射线荧光光谱仪对这种体积小的样品进行成分分析,所测样品的主要成分为Zr,其次为Y,为合成立方氧化锆的主要成分。利用样品的成分分析,可以快速、无损鉴定成分简单的宝石品种。     

营养强化预配粉的研究

本文针对我国人民蛋白质和钙摄取不足的现状，探讨了采用在我国北方人民的主食面粉中强化钙、蛋白质和纤维素的品种、数量对制作面包的感官和理化指标的影响，并且提出了强化的最佳配方：每Kg面粉强化11．8g乳配钙为最佳钙强化配方:每Kg面粉强化4％大豆蛋白、5％麦麸纤维素、1％添加剂为最佳配方。     

乳矿物盐的研究动态及应用进展

乳矿物盐又名乳钙、乳清矿物质浓缩物、乳清钙,来源于牛乳,是将牛乳通过膜渗透、分离、浓缩和喷雾干燥等工艺处理后得到的乳白色粉末。其主要成分是磷酸钙,除此之外还包括蛋白质、乳糖及锌、磷、钠、钾、镁、等丰富的营养成分,含钙量约为23%～28%,其钙磷比为2:1,较利于人体的吸收利用,作为一种新的钙源被广泛用于各种食品。乳矿物盐的生产工艺及安全性乳矿物盐来源于牛乳,是将牛乳中天然存在的钙及矿物质盐通过膜技术分离浓缩得到的含钙量较高乳矿物质。具体     

高粱糖生物活性物质成分分析

目的对高粱糠中的生物活性物质植物蛋白质、菲汀、氨基酸、微量元素、酸性纤雏等进行测定.方法生物活性物质成分测定.结果高粱糠中含有蛋白质、菲汀、氨基酸、微量元素、酸性纤维等成分.结论高粱糠中含有8种氨基酸,植物蛋白质含量为4.4%,菲汀含量为5.3%,脂肪含量为1.45%,酸性纤维含量为34 38%.     

电感耦合等离子体发射光谱仪(ICP-AES)法测定牛奶及奶制品中的微量元素

目前,电感耦合等离子发射光谱仪(ICP-OES)已应用于石油化工等各领域,但在食品领域的应用甚少,尤其在测定乳及乳粉中微量元素(钙、钾、镁、钠、磷、铁、锌、锰、铜)方面的应用更少.采用电感耦合等离子体发射光谱仪(ICP-AES)测定牛奶及奶制品中的微量元素,方法中各种元素标准曲线的R2值均在0.999以上,回收率为95.26%～106.28%,栓出限为0.027～0.87 mg/L,KSD值为0.021%～2.01%.结果表明该方法精密度高、准确性好、干扰少、快速简单,可用于牛奶及奶制品中微量元素的含量测定.     

氮离子束诱变蟹味菇菌株的营养价值及油菜秸秆栽培研究

采用氮离子束诱变蟹味菇菌株,通过测定出菇产量、生物学效率、麦角甾醇含量、糖与蛋白质等常规营养成分含量,筛选出优质突变菌株X-004.X-004菌株的产量、麦角甾醇、蛋白质和粗纤维含量在各诱变菌株中均为最高,产量达139.22g,麦角甾醇在菌盖中含量为4.228mg/g,菌柄中为1.690mg/g,蛋白质和粗纤维含量分别达到35.41％和23.29％.该菌株的最适油菜秸秆栽培配方为:油菜秸秆35％,棉籽壳35％,麸皮13％,蔗糖1％,过磷酸钙1％,玉米粉5％,米糠10％.     

国外保健食品中常用的添加成份

据美国《食品加工》报道，近年来保健食品中常用的一些添加成分里首推钙，新西兰乳制品公司采用一种新方法处理钙，他们将价格低廉的原料碳酸钙与乳蛋白质或大豆蛋白质相结合，喷雾干燥后制成高钙蛋白质。这种高钙蛋白质可溶于黏度较低的液体或水中，并能在高酸度制品中保持稳定。因此，可将它用于多种食品如冰淇淋、饼干、点心馅、干酪粉、咖啡伴侣等，可大大提高这些食品的含钙量及营养需求量。乳制品中新近最热门的添加成分是乳酸菌和双歧杆菌等活菌。目前除酸乳外还在干酪、酸奶油、冰淇淋甚至括计中添加活菌。活菌的益处是能产生有助于…     

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.     

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.     

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%。     

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     

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。     

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.     

高钙奶中不同钙剂对其稳定性的影响

本文重点研究了钙强化剂的种类、不同用量和不同的稳定剂对高钙奶稳定性的影响.结果表明以碳酸钙为代表的电离度较小的分子钙,其电离产生的钙离子对乳状液体系的稳定性的影响相对较小,因此主要通过提高乳状液的悬浮效果,可解决由于加入碳酸钙而引起的体系出现沉淀的问题;以乳钙为代表的有机分子钙,由于乳钙自身在水溶液中具有很好的分散性,电离度较碳酸钙大,乳钙对高钙奶体系稳定性的影响主要是游离的钙离子与乳状液中界面上的乳蛋白通过桥连作用,引起体系絮凝,可通过加入螯合剂螯合体系的钙离子来解决.