茶中放射性及其向茶汤的转移

茶中放射性及其向茶汤的转移邓国伦，兰绪萍，宋良治，杨克毅，向长兴四川省放射卫生防护所６１００４１饮茶有利健康已取得人类共识，诸如提神解乏，利尿明目，消炎解毒，抗病防衰，健美，防辐射，防癌等。但茶的成分复杂，亦含有害物质，故饮茶从来有禁忌，近来已见饮茶...     

茶汤里的故事

在北京多年。老北京小吃尝了不少，几乎每一样都像皇城根下的青砖写满了历史和故事。从豆汁儿到炒肝，从羊杂汤到驴打滚，那其中的技术、讲究，叫懂行的人几天几夜也说不完。面茶汤，是我曾经吃过的小吃，本没有太多印象，但最近看到一篇中学课文讲的是天津卖面茶汤小买卖人和他们的故事。作为故事的主角一一茶汤，引起了我的浓厚兴趣。     

火焰原子吸收法测定血清中结合钙和非结合钙

血清样品用硫酸铵固体盐析后,过滤,滤液即为非结合钙(游离钙)溶液,采用基体匹配的方法分别测定非结合钙和总钙含量,基差值便为蛋白结合钙。该法精密度为2.6％～3.4％,回收率为95.4％～104.5％。     

加钙食品中钙含量的测定

目前钙含量的测定常用的方法有火焰原子吸收法、EDTA络合量法及高锰酸钾法[1 - 3 ] 。原子吸收法因价格昂贵尚未在基层单位普及 ,且干扰因素较多 ;高锰酸钾法自 EDTA络合滴定法后也已很少使用。目前最为常用的是 EDTA络合容量法。在工作中我们用重量络合法对食品中钙进行了尝试性测定 ,结果较好 ,与容量络合法相比 ,操作更快速方便 ,具有一定的准确性和可行性。1　实验部分1.1　方法原理　在 p H值为 12～ 13范围内钙与氨羧络合剂EDTA定量形成的络合物 ,其稳定性强于钙与钙指示剂所形成的粉红色络合物 ,在达到等当点时 ,EDTA就从指…     

乳清蛋白肽对骨密度和骨钙含量的影响

目的利用胰蛋白酶水解乳清蛋白制备促钙吸收肽,研究乳清蛋白肽对生长期小鼠骨密度的影响。方法选用ICR小鼠,按体重随机分成低钙组、补钙组、正常组和样品组,样品组以灌胃方式给予钙和乳清蛋白水解肽。4w后处死,取小鼠双侧股骨湿重、干重、长度和股骨指数。结果含肽低、高剂量组的股骨长度分别为16.62±0.39和16.97±0.29 mm,均显著(P0.05)大于低钙对照组16.36±0.41mm;含肽低、高剂量组小鼠股骨密度分别为1.417±0.044和1.429±0.042 g/cm3,显著(P0.05)或极显著(P0.01)大于低钙对照组1.335±0.122 g/cm3;含肽高剂量组小鼠的股骨干重为0.0666±0.0042g,显著(P0.05)大于低钙对照组(0.0536±0.0022)和补钙组0.0596±0.0052 g;含肽低剂量组小鼠的股骨钙含量为221.16±6.24 mg/g显著(P0.05)大于低钙对照组213.46±12.65 mg/g;含肽高剂量组的股骨钙含量为228.55±5.18 mg/g极显著(P0.01)大于低钙对照组213.46±12.65 mg/g和补钙组215.32±15.72 mg/g。结论乳清蛋白水解肽对钙吸收有显著促进作用,并具有剂量效应。     

海南省市售苦丁茶和鹧鸪茶及茶汤中9种元素污染特征及健康风险评估

目的 了解海南省市售苦丁茶和鹧鸪茶及茶汤中铝、铜、锰、铬、镉、铅、镍、砷、汞9种元素的含量,并估计饮用茶汤对人体健康风险。 方法 于2017—2018年在海南省采集市售苦丁茶和鹧鸪茶,采用微波消解-电感耦合等离子质谱仪检测茶叶及茶汤中9种元素的含量,采用美国环保署(the United States Environmental Protection Agency,USEPA)提出的THQ 和HI评估茶叶和茶汤元素污染的人体健康风险。 结果 苦丁茶中镉含量均值为5.46 mg/kg,超标率为82.0%,鹧鸪茶9种元素含量均未超过国家标准限值。苦丁茶茶汤中存在Cd、Mn和Al含量超出国家生活用水限量标准,鹧鸪茶茶汤中存在Mn和Ni含量超过国家生活用水限量标准,并随着浸泡次数的增加其元素含量也随之降低。苦丁茶HI值为1.147,第一道茶汤至第三道茶汤HI值范围为0.341～0.117;鹧鸪茶HI值为0.346,第一道茶汤至第三道茶汤HI值范围为0.314～0.132。 结论 饮茶者应弃去第一浸茶汤,饮用海南省市售苦丁茶和鹧鸪茶茶汤无健康风险,但需要加强对苦丁茶中Cd、As和Mn,鹧鸪茶中Mn和As元素的监测。     

包装食品中钙含量分析和变化范围的研究

目的研究不同实验室对包装食品中钙检测的实验误差。方法根据2000年全国包装食品消费的调查,选择了7类(谷物、豆类、肉类、奶制品类、饮料类、坚果、休闲食品)14种包装食品,在全国的7家实验室进行3次钙的平行样检测,钙检测方法为国家标准方法。结果所有钙检测结果筛查合格率为78.6%。钙检测精密度为:实验室内变异系数2.21%~8.13%;除钙含量低的鱼罐头外,实验室间5.51%~31.12%,室内和室间总和为5.93%到31.24%,平均22.10%。除钙含量低的鱼罐头外,钙检测的95%相对扩展不确定度由10.36%到57.10%,平均39.78%。结论中国实验室内对钙的检测符合国家标准方法的要求,绝大多数包装食品的实验室分析不确定度在60%以内。     

人发和血清中钙镁含量分析

报告了５８例人发和血清中钙镁的检测结果。结果显示发中钙镁含量明显高于血清中钙镁含量；发中钙镁含量黑发＞花白发＞白发，差别十分显著，Ｐ＜０．００１；发钙与发镁、血清钙与血清镁之间呈显著性正相关；但发钙镁与血清钙镁之间相关性不明显。     

饲料钙水平对大鼠血钙及钙调蛋白的影响

为研究饲料中钙与血钙（Ｃａ）及钙调蛋白（ＣａＭ）的关系，本实验通过在大鼠低钙饲料中补充不同量的钙，平行研究饲料内钙水平对血钙及ＣａＭ的影响。Ｗｉｓｔａｒ大鼠按体重和性别分层均匀分为７组。基础低钙（ＬＣ）饲料是以玉米面为主的膳食配方配制，其中低钙特别突出。ＬＣ组大鼠血清钙水平明显低下，仅及常规饮食（ｓｔｏｃｋ）组的一半，体重增长迟缓，下丘脑ＣａＭ活性明显低下；当饲料补Ｃａ后，血Ｃａ水平随补Ｃａ量逐渐升高，补Ｃａ可使ＣａＭ水平升高，体重也随之升高，呈明显的量效关系，ＬＣ＋６００ｍｇ／ｋｇＣａ组血Ｃａ接近正常水平。说明饲料低钙、低血Ｃａ和细胞内ＣａＭ三者的变化是紧密联系的。当饲料内总钙在１０００ｍｇ／ｋｇ时，即ＬＣ＋６００ｍｇ／ｋｇ组，上述生长迟缓的状态即得到改善，Ｐ＜０．０１。     

纳米珍珠粉中钙的吸收和利用研究

目的:探讨纳米珍珠粉对大鼠钙吸收与利用的影响。方法:70g左右的SD大鼠100只,以低钙基础饲料饲喂2w后分别添加5%、10%的纳米珍珠粉和微米珍珠粉,另10只大鼠为实验本底组。观察大鼠生长状况,检测大鼠股骨钙、粪钙、尿钙、血钙及饲料钙含量、股骨干重与长度、血磷含量。结果:纳米珍珠粉组大鼠体重增加、股骨长度、股骨干重及股骨钙存留率均明显高于微米珍珠粉组;纳米珍珠粉组大鼠钙吸收率及利用率也明显高于微米珍珠粉组。结论:纳米珍珠粉可被机体很好地吸收利用,可应用于食品营养强化和补钙药物。     

Effect of green tea extract microencapsulation on hypertriglyceridemia and cardiovascular tissues in high fructose-fed rats

The application of polyphenols has attracted great interest in the field of functional foods and nutraceuticals due to their potential health benefits in humans. However, the effectiveness of polyphenols depends on their bioactivity and bioavailability. In the present study, the bioactive component from green tea extract (GTE) was administrated orally (50 mg/kg body weight/day) as free or in a microencapsulated form with maltodextrin in rats fed a high fructose diet. High fructose diet induced features of metabolic syndrome including hypertriglyceridemia, hyperuricemia, increased serum total cholesterol, and retroperitoneal obesity. In addition, myocardial fibrosis was increased. In rats receiving high fructose diet, the lowering of blood triglycerides, total cholesterol, non esterified fatty acid (NEFA) and uric acid, as well as the reduction in final body weight and retroperitoneal fat weight associated with the administration of GTE, led to a reversal of the features of metabolic syndrome (P < 0.05). In particular, the administration of microencapsulated GTE decreased myocardial fibrosis and increased liver catalase activity consistent with a further alleviation of serum NEFA, and hyperuricemia compared to administration of GTE. Taken together, our results suggest that microencapsulation of the bioactive components of GTE might have a protective effect on cardiovasucular system by attenuating the adverse features of myocardial fibrosis, decreasing uric acid levels and increasing hepatic catalase activity effectively by protecting their bioactivities.     

绿茶提取物的安全性分析评价

目的　对调节血糖产品-绿茶提取物的安全性进行评价。方法　采用急性经口毒性试验、蓄积毒性试验、小鼠骨髓嗜多染红细胞微核试验、V79细胞基因突变试验对绿茶提取物的急性毒性、蓄积毒性、遗传毒性进行观察。结果　该提取物对雌、雄性小鼠急性经口LD50 均>10 0 0 0mg/ (kg·bw) ,属于实际无毒级;对动物蓄积系数K >5 ,属于弱蓄积性;对小鼠骨髓细胞未产生致畸变作用;对体外培养的中国仓鼠肺细胞(V79) ,无论直接作用和代谢活化后作用,均未呈现致突变性。结论　绿茶提取物是一种安全的调节血糖制剂。     

以葛根提取物和藤茶粉为主要材料的配方的醒酒功能研究

目的 探讨并比较以葛根提取物和藤茶粉为主要材料的两种天然产物配方对急性酒精中毒小鼠乙醇脱氢酶（ADH）和乙醛脱氢酶（ALDH）活性的影响。方法 将18～22 g SPF级雄性KM小鼠随机分为AL[A配方低剂量：470mg/（kg·bw）]、AH[A配方高剂量：1 400 mg/（kg·bw）]、BL[B配方低剂量：400 mg/（kg·bw）]、BH[B配方高剂量：1 200 mg/（kg·bw）]、空白对照组、模型对照组、阳性对照组[海王金樽：1 500 mg/（kg·bw）]共7组,A、B配方组和阳性对照组按照受试物对应剂量灌胃14 d,模型对照组和空白对照组灌胃双蒸水[灌胃剂量：20 ml/（kg·bw）],第15 d除空白组外其余组灌胃52°白酒[灌胃剂量：22 ml/（kg·bw）]后观察翻正反射消失时间;酒精灌胃后的1、2和3 h分别进行眼眶取血检测血乙醇、乙醛含量变化趋势;取肝脏测定ADH和ALDH活性以及HE染色观察肝脏病理变化。结果 AH、BL、BH组ADH活性高于模型组（P=0.002;P=0.003;P=0.003）;A、B高低剂量ALDH活性高于模型组（P<...     

Antihypercholesterolemic effect of Chinese black tea extract in human subjects with borderline hypercholesterolemia

A water-soluble extract of a traditional Chinese black tea (Pu-Ehr) has been shown to precipitate mixed bile salt micelles in foods. In addition, long-term ingestion of this black tea extract (BTE) significantly reduces blood cholesterol levels in rats. We investigated the effects of BTE tablets (a formula designed to enhance compliance) as a dietary supplement in a 3-month double-blind randomized group comparison study in borderline hypercholesterolemic human subjects (n = 47). All subjects ingested BTE tablets (333 mg) or placebo 3 times daily before meals for 3 months. In the BTE-treated group, the initial mean blood total (6.14 ± 0.14 mol/L) and low-density lipoprotein (LDL) cholesterol (4.32 ± 0.14 mol/L) levels decreased with time and were significantly (P < .01) lower (total cholesterol, 5.62 ± 0.11; LDL cholesterol, 3.81 ± 0.13 mol/L) after 3 months of ingestion. Furthermore, the mean body weights (P < .05) and triacylglycerol levels (P < .01) were also significantly reduced after 3 months of BTE intake compared with the baseline levels. Significant improvements in the mean LDL cholesterol, body weight, and triacylglycerol values were not accompanied with undesirable changes in other biochemical parameters measured in the subjects. None of the subjects complained of any adverse effects (eg, abdominal distension). The results indicate that BTE intake elicited a significant antihypercholesterolemic effect and might be useful for improving blood cholesterol levels in subjects at risk for heart disease or obesity.     

茶及茶中多酚类化合物减肥作用的研究进展

近10年来,肥胖患病率明显增加,已成为现代医学最严重问题之一。据报道,茶儿茶素尤其是绿茶儿茶素具有抗肥胖作用。然而,由于茶的品种各异,萃取条件不同,以致研究结果出现不一致的结论。最新的研究发现,脂肪酸合酶与肥胖相关,而茶多酚对脂肪酸合酶具有可逆和不可逆的双重作用,这可能成为茶及茶中多酚类化合物抗肥胖作用机制研究的新途径。目前,关于茶减肥的机制性研究主要集中在绿茶及绿茶多酚方面。因此,有必要对其他茶及茶多酚减肥作用及机制进行进一步研究。     

Green tea extract supplementation gives protection against exercise-induced oxidative damage in healthy men

The purpose of this study was to evaluate the effects of a long-term (4-week) green tea extract (GTE) supplementation in combination with strength training on selected blood markers of oxidative stress and muscular damage after a short-term exercise in previously untrained men. We hypothesized that GTE supplementation would elevate antioxidant potential and attenuate exercise-induced oxidative stress and muscular damage. Thirty-five male students were exposed to 4 weeks of strength training and received (in a randomized, double-blind design) GTE (n = 17; 640 mg polyphenols/d) or placebo (P; n = 18). Before (term I) and after 4 weeks of strength training and supplementation (term II), students performed a short-term muscular endurance test. Blood samples were collected at rest, 5 minutes after the muscular endurance test, and after 24 hours of recovery. Supplementation with GTE enhanced plasma total polyphenols at rest and 5 minutes after the muscular endurance test. Supplementation also contributed to the rise of resting total antioxidant status in plasma. Throughout the experiment (terms I and II), a reduction in plasma lipid hydroxyperoxides was observed 24 hours after the muscular endurance test. Four weeks of strength training resulted in an increase in plasma lipid hydroxyperoxides at rest, but only in the P group. In term I, the muscular endurance test induced an increase in activity of creatine kinase in plasma after 24 hours of recovery in both the P and GTE groups. In term II, plasma creatine kinase activity after 24 hours of recovery was elevated only in the P group. In conclusion, in previously untrained men, dietary supplementation with GTE (in combination with strength training) enhances the antioxidant defense system in plasma at rest and, in turn, may give protection against oxidative damage induced by both short-term muscular endurance test and long-term strength training.     

茶色素的制备和化学成分分析

目的　制备茶色素。方法　以斯里兰卡红碎茶为原料 ,用传统的溶剂萃取法制备茶色素。结果　茶色素中的内含化学成分经HPLC分析表明 ,该茶色素中含咖啡碱 1 77%、表没食子儿茶素 1 37%、儿茶素1 2 0 %、表儿茶素 9 5 5 %、表没食子儿茶素没食子酸酯 10 5 2 %、表儿茶素没食子酸酯 9 94 %、茶黄素10 34%、茶黄素单没食子酸酯 9 5 7%、茶黄素双没食子酸酯 4 81%、茶红素约 4 0 93%。结论　此方法通过控制不同制备条件 ,来达到茶色素制品化学成分的最佳配比     

绿茶及其有效成分对肾性高血压大鼠左室肥厚抑制作用的研究

目的研究绿茶及其提取物对肾性高血压大鼠左室肥厚的抑制作用机制。方法雄性Wistar大鼠160只,体重180~220g,随机分为5组,建立二肾一夹法大鼠肾性高血压左室肥厚模型:假手术组(SHAM)和手术组(2K1C)正常饮水;手术+绿茶组(2K1C+GT)饮用2%绿茶水;手术+茶多酚组(2K1C+TP)饮用0.1%茶多酚水;手术+EGCG组(2K1C+EGCG)饮用0.05%EGCG水,术后即给予不同浓度的绿茶及其提取物,持续8周直至实验结束。结果与假手术组比较,手术组和各饮茶组血压、左心室与体重比值(LVW/BW)和左心室壁厚度(LVWT)均显著升高(P<0.01)。而与手术组相比,不同浓度的绿茶及其有效成分(2%绿茶、0.1%茶多酚、0.05%EGCG)左心室重/体重(LVW/BW)、左心室壁厚度显著降低,抗氧化酶(SOD和GSH-Px)的活性升高,活性氧自由基(ROS)以及Ras和ERK1/2蛋白表达降低,但对大鼠收缩压无显著性影响。结论绿茶及其提取物对肾性高血压大鼠左室肥厚有抑制作用,其机制可能是由于茶及其有效成分具有抗氧化活性,能够清除ROS,以及对Ras-MAPK信号传导通路的调控有关。     

茶多酚和茶色素对人肝癌细胞株HepG2细胞凋亡的影响

目的利用人肝癌细胞株HepG2探讨茶多酚和茶色素对细胞凋亡的影响。方法5×105个孔HepG2接种于6孔培养板中,于指数生长期加入50mgL和100mgL茶多酚和茶色素,48h后消化细胞,制成细胞悬液。用琼脂糖凝胶电泳检测DNALADDER的形成,Westernblot方法检测细胞凋亡蛋白Bcl2和Bax的表达。结果茶多酚和茶色素诱导了明显的DNALADDER的出现,Westernblot分析发现茶多酚和茶色素显著抑制了Bcl2表达,诱导了Bax蛋白表达。结论诱导细胞凋亡是茶预防肿瘤的一个重要机制。