食品及水体中碘形态分析研究进展

碘是人体必需的一种微量元素。但是由于碘在自然环境中的分布不均匀,不同地区人群的碘摄入会产生缺乏或过量的现象,进而引起一系列的疾病。我国是世界上碘缺乏最严重的国家之一,因此实施食品及相关水体中碘含量的监测是一项长期的基本任务。然而碘在自然环境中的存在形式复杂,不同形态碘的生物有效性及毒性差异很大,因此开展不同形态碘含量的监测对于科学、准确评估人群的碘摄入具有重要意义。本文总结了近十多年来碘形态分析技术的发展,比较了各种前处理技术及分离分析技术的优缺点及适用范围,以期为相关科研工作者开展进一步的工作提供参考。     

红芸豆淀粉结构特征及其降解性质的研究

以红芸豆为原料,研究淀粉在红芸豆籽粒中的形态及其在加工中的变化。显微镜观察结果表明,在罐制产品中,淀粉仍然以颗粒形态存在。采用模拟人体肠道的降解方法获得红芸豆抗性淀粉,然后对红芸豆抗性淀粉的颗粒形貌、分子量分布、碘结合能力、直链淀粉-碘络合可见光扫描图谱以及直链淀粉-碘络合物的的形态进行了分析。结果显示,红芸豆抗性淀粉颗粒分布范围窄,呈多边形态,其分子主要是由短链的直链淀粉分子组成。     

氯氧化碘的反应和氯水氧化树脂法提碘工艺原理

氯水氧化树脂法提碘,是二十世纪七十年代工业化了的最新提碘工艺方法。它所独具的特点是:对pH10以下以Ⅰ~-形态存在于水溶液里的碘,不用预先加酸酸化直接加氯水氧化,然后用强碱性阴离子交换树脂吸附氧化液中的Ⅰ_2和Ⅰ~-,以达到高收率提碘的目的。本文着重讨论氯氧化碘的反应,同时对氯水氧化树脂法提碘工艺原理作简略介绍。     

碘·智慧·智力工程

碘·智慧·智力工程陈修喜人类的生存发展离不开健康的体魄，在组成机体的各种物质中，有一类所占比例虽小但作用甚大的物质──矿物质，依其含量多少，人们又将之细分为大量元素和微量元素。目前已知的微量元素有１４种，碘就是其中之一。碘在人体血液中以碘化物形态存在...     

液相色谱-电感耦合等离子体-质谱法分析海藻碘浓缩液中砷形态

目的 建立液相色谱-电感耦合等离子体质谱法(liquid chromatography-inductively coupled plasma mass spectrometry, LC-ICP-MS)测定海藻碘浓缩液中6种不同形态砷化合物的分析方法。方法 单因素实验确定对不同形态砷化合物LC-ICP-MS的分离条件, 包括流动相浓度、pH及洗脱方式。以总砷提取效率的高低评价三种不同的提取砷化合物的方法, 确定最佳方法。结果 以稀硝酸浸提的前处理方法的提取效果最佳, 提取效率为84.28%~92.99%;以25 mmol/L pH8.0磷酸二氢铵溶液和水作为流动相, 采用梯度洗脱的方式, 可以将6种砷形态完全分离,结果显示6种海藻碘样品中砷甜菜碱AsB含量较多, 而亚砷酸盐As(III)、砷酸盐As(V)和二甲基砷酸DMA含量较少, 未检测出砷胆碱AsC和一甲基砷酸MMA, 样品有毒砷含量占浓缩液总砷含量的2.01%~3.69%, 本方法加标回收率在80.4%~101.5%之间。结论 海藻碘浓缩液中砷形态的主要存在形式为AsB,本方法准确、简单,适合海藻碘浓缩液中砷形态分析。     

海带中有机碘的动物补碘评价

目的:比较无机碘与海带有机碘补碘效果上的差异,评价海带生物有机碘的动物补碘效果,为科学补碘提供安全的补碘剂方法:(1)4组小鼠分别饲以不同剂量KI:1μg碘/d·只、6μg碘/d·只、60μg碘/d·只、100μg碘/d·只 (2)3组小鼠各饲喂不同剂量海带有机碘:60μg碘/d·只、100μg碘/d·只、200μg碘/d·只(3)Babl/c小白鼠3组,第1组每日额外饲喂KI,120μg碘/d·只第2、3组除摄无机碘120μg/d·只外,额外饲喂海带活性碘液(折合碘为20μg/d·只)(4)高碘甲肿小鼠两组,第1组饲以海带活性碘剂(折合碘为20μg/d·只),第2组则喂以标准饲料自愈(5)饲养180d后称重、处死,检查各组小鼠体量、甲状腺形态和重量变化结果:无机碘摄入过量,小鼠体重减轻、甲状腺肿大,摄入超过40μg碘/d·只,明显肿大;而海带有机碘摄入量即使过200μg碘/d·只,小鼠甲状腺也未见明显肿大;同补海带有机碘可防治高碘甲肿,海带有机碘是一种新型安全的补碘剂。     

我国海藻资源利用新技术研究有重大进展

日前 ,由国家海洋局组织的“九五”国家重点科技攻关项目“海藻资源利用新技术研究”专家评审结果表明 ,我国海藻资源利用新技术研究有了重大进展。专题对马尾藻碘晶及海藻天然抗氧化剂进行了较深入的基础研究 ,基本摸清了马尾藻碘及海藻多酚的含量、分布特征和化学形态 ,发现了某些马尾藻碘含量明显高于海带 ,从中确立了目标材料 ,并选取合适的溶媒体系 ,建立和完善了产品的提取和浓缩工艺。同时 ,还进行了海藻多酚及马尾藻碘晶的毒理、抗氧化效果、人体补碘及产品的稳定性等实验。证明了马尾藻碘晶是一种独具特色的补碘保健品 ,所研制的海…     

加碘盐中碘的稳定性

由于在环境温度下碘容易升华，盐加碘计划的效果取决于碘载体－碘酸钾的稳定性。由于杂质，金属离子，像铁离子吸湿，水分的存在加速了碘的损失。用防潮膜包装能大大增加所有盐样品中碘的保存。     

加碘食盐中碘损失的实验研究

采用氯化钠增敏光度法研究了在模拟烹调条件下加碘食盐中碘的稳定性。实验结果表明，碘盐中碘的稳定性并不理想。在温度较高的条件下存在不同程度的损失。加碘盐中碘的损失量受温度与受热时间的影响：温度越高。碘损失越多；受热时间越长，碘损失越多。     

织物上PVA与淀粉混合浆料的着色检验法

在单独用PVA或者淀粉上浆过的织物上检验其浆料性质是很简单的。但是当两种浆料混合使用的时候,检验时就较困难。 通常,碘着色法用来检定淀粉,而硼酸/碘着色法则用来检定PVA。可是当两种浆料混合使用时,虽然仍可用碘试验来检验淀粉的存在。但是,硼酸/碘试验却不能用来检验PVA的存在了,原因是:淀粉同硼酸/碘试剂要形成紫色的络合物,此络合物的颜色将遮没PVA络     

Concentration-dependent mobility, retardation, and speciation of iodine in surface sediment from the Savannah River Site

Iodine occurs in multiple oxidation states in aquatic systems in the form of organic and inorganic species. This feature leads to complex biogeochemical cycling of stable iodine and its long-lived isotope, (129)I. In this study, we investigated the sorption, transport, and interconversion of iodine species by comparing their mobility in groundwaters at ambient concentrations of iodine species (10(-8) to 10(-7) M) to those at artificially elevated concentrations (78.7 μM), which often are used in laboratory analyses. Results demonstrate that the mobility of iodine species greatly depends on, in addition to the type of species, the iodine concentration used, presumably limited by the number of surface organic carbon binding sites to form covalent bonds. At ambient concentrations, iodide and iodate were significantly retarded (K(d) values as high as 49 mL g(-1)), whereas at concentrations of 78.7 μM, iodide traveled along with the water without retardation. Appreciable amounts of iodide during transport were retained in soils due to iodination of organic carbon, specifically retained by aromatic carbon. At high input concentration of iodate (78.7 μM), iodate was found to be reduced to iodide and subsequently followed the transport behavior of iodide. These experiments underscore the importance of studying iodine geochemistry at ambient concentrations and demonstrate the dynamic nature of their speciation during transport conditions.     

A multicenter community study on the efficacy of double-fortified salt

BACKGROUND: Iron and iodine deficiencies affect more than 30% of the world's population. Typical Indian diets contain adequate amounts of iron, but the bioavailability is poor. This serious limiting factor is caused by low intake of meat products rich in heme iron and intake of phytates in staple foods in the Indian diet, which inhibits iron absorption. OBJECTIVE: To test the stability of double-fortified salt (DFS) during storage and to assess its efficacy in improving the iron and iodine status of the communities. METHODS: The stability of both iodized salt and DFS during storage for a 2-year period was determined. The bioefficacy of DFS was assessed in communities covering three states of the country for a period of 1 year. This was a multicenter, single-blind trial covering seven clusters. The experimental group used DFS and the control group used iodized salt. The salts were used in all meals prepared for family members, but determination of hemoglobin by the cyanmethemoglobin method was performed in only two or three members per family, and not in children under 10 years of age (n = 393 and 436 in the experimental and control groups, respectively). The family size was usually four or five, with a male: female ratio of 1:1, consisting of two parents with two or three children. Hemoglobin was measured at baseline, 6 months (midpoint), and 12 months (endpoint). Urinary iodine was measured in only one cluster at baseline and endpoint. All the participants were dewormed at baseline, 6 months, and 12 months. RESULTS: The iron and iodine in the DFS were stable during storage for 2 years. Over a period of 1 year, there was an increase of 1.98 g/dL of hemoglobin in the experimental group and 0.77 g/dL of hemoglobin in the control group; the latter increase may have been due to deworming. The median urinary iodine changed from 200 microg/dL at baseline to 205 microg/dL at the end of the study in the experimental group and from 225 microg/dL to 220 microg/dL in the control group. There was a statistically significant (p < .05) improvement in the median urinary iodine status of subjects who were iodine deficient (urinary iodine < 100 microg/L) in both the experimental and the control groups, a result showing that DFS was as efficient as iodized salt in increasing urinary iodine from a deficient to sufficient status. There was a statistically significant increase (p < .05) in hemoglobin in all seven clusters in the experimental group compared with the control. CONCLUSIONS: The iron and iodine in the DFS are stable in storage for 2 years. The DFS has proved beneficial in the delivery of bioavailable iron and iodine.     

海藻中碘的形态及其食用安全性研究进展

碘是人体甲状腺激素合成的必需元素,也是人体必需的微量元素之一。依据世界卫生组织提出的食盐加碘补碘策略, 1994年我国颁布了《食盐加碘消除碘缺乏危害管理条例》。但长期过量摄入无机碘,不仅会引起甲状腺功能失调,增加患甲状腺癌的几率,还会导致其他组织器官病变。海藻是天然的食用碘资源,有机碘含量最高达80%。通过海藻碘、有机碘和无机碘的毒性研究发现,长期大量摄入海藻碘和有机碘对甲状腺的危害要小很多。本文分析了我国补碘现状及国内外碘的限量,对比海藻碘、有机碘和无机碘的毒性差异,阐述当前海藻碘的毒性研究进展,为进一步开展海藻碘的食用安全性评估和制定碘的限量提供参考。     

多法并用解决加碘均匀问题

我公司为解决加碘不均匀问题,从加碘设备、加碘工艺方法及加碘人员素质等方面进行全面改进和提高,使成品盐加碘一次合格率达到99.98%,效果理想。     

Influence of various iodine supplementation levels and two different iodine species on the iodine content of the milk of cows fed rapeseed meal or distillers dried grains with solubles as the protein source

Supplementation of animal feed with iodine influences the iodine content of milk and therefore, in addition to salt iodination, provides another possibility for improving the human iodine supply. On the other hand, excessive iodine intake by humans through drinking milk must be avoided. Furthermore, the iodine content of milk varies, depending on the presence of iodine antagonists in feed (e.g., glucosinolates in rapeseed) and the applied iodine species. This study evaluated the impact of various feed iodine supplementation levels up to the permitted maximum level, the effect of applying rapeseed compared with a glucosinolate-free ration, and the impact of 2 different iodine species on the iodine content of milk. A total of 32 dairy cows were divided into 4 groups with 8 animals each. Two groups received distillers dried grains with solubles (DDGS) as the protein source, and the others received rapeseed meal (RSM, 16.5% of total diet). In each case, half the animals received feed supplemented with iodine in the form of potassium iodide, and the other half received feed supplemented with iodine in the form of calcium iodate. Iodine supplementation levels of 0, 0.5, 1, 2, 3, 4, and 5 mg/kg of dry matter (DM) were tested in consecutive periods of 21 d each. The milk iodine concentration increased with increasing iodine supplementation of the feed. Rapeseed meal in the ration (0.58 mmol of glucosinolates/kg of diet DM) diminished the milk iodine concentration by up to one-half to one-third of the concentration achieved by DDGS. At iodine supplementation levels of 2 mg/kg of DM and higher, the differences were significant. The application of iodate predominantly resulted in higher milk iodine concentrations compared with iodide, but not significantly in any period. At the highest tested iodine supplementation (5 mg/kg of DM), the milk iodine concentration increased up to 1,464 (iodide) and 1,578 μg/kg (iodate) when feeding DDGS and up to 718 (iodide) and 620 μg/kg (iodate) in the RSM groups. The carry over of iodine from feed into milk amounted to 30 to 56% when using DDGS, and 11 to 25% when using RSM. The maximum level of iodine currently allowed in the feed of dairy cows in Europe could lead to high milk iodine concentrations. As a result, the Tolerable Upper Intake Level in human nutrition could be exceeded. Therefore, this maximum level needs to be reevaluated. In addition to iodine supplementation, the application of RSM in the ration must be considered when estimating the iodine content of milk.     

Urinary iodine concentration of pregnant women and female adolescents as an indicator of excessive iodine intake in Sri Lanka

BACKGROUND: Mild deficiencies and excesses of iodine have deleterious effects in both females and males. The iodine status of the population after implementation of the universal salt iodization program in Sri Lanka is not known. OBJECTIVE: This cross-sectional study was carried out to assess the iodine status of pregnant women and female adolescents, with urinary iodine concentration used as the measure of outcome. METHODS: The participants were 100 women in the first trimester of pregnancy and 99 female adolescents in Kuliyapitiya, Kurunegala District, North-Western Province, Sri Lanka. The urinary iodine concentration was measured in a casual urine sample from each subject. The iodate contents of salt samples collected from households of the adolescents participating in the study were also measured. RESULTS: The median urinary iodine concentration of 185.0 microg/L and the prevalence of values under 50 microg/L of only 1% among the pregnant women indicate adequate iodine intake and optimal iodine nutrition. The median urinary iodine concentration (213.1 microg/L) among female adolescents indicates a more than adequate iodine intake and a risk of iodine-induced hyperthyroidism. Approximately 8% and 4% of the adolescents and pregnant women, respectively, had urinary iodine concentrations in the range of mild iodine deficiency (51 to 100 microg/L). More than half of the adolescents (56%) and 39% of the pregnant women had urinary iodine concentrations higher than optimal. The median iodine content in salt samples was 12.7 ppm. Only 20.2% of the samples were adequately iodized, and 10.1% of the samples had very high iodine levels. CONCLUSIONS: Female adolescents and pregnant women had no iodine deficiency, but a considerable proportion of them, especially female adolescents, were at risk for iodine-induced hyperthyroidism. There is thus a need for proper monitoring of the salt iodization program to achieve acceptable iodine status.     

Iodine from brown algae in human nutrition,with an emphasis on bioaccessibility,bioavailability, chemistry,and effects of processing: A systematic review

Brown algae are becoming increasingly popular as a food source and dietary supplement in Europe and other Western countries. As they are highly rich in iodine, they represent a potential new dietary iodine source. Iodine deficiency has been re-emerging in Europe, and it is important to ensure adequate intake through one's diet. However, macroalgae, and especially brown algae, may contain very high amounts of iodine, and both iodine deficiency and excessive iodine may increase the risk of negative health effects. The iodine content of algae or foods containing algae is currently not regulated in the European Union. The aim of this paper is to review the literature to determine the chemical species of iodine in brown algae, the loss of iodine during processing, and the bioavailability and bioaccessibility of iodine. A systematic search of the literature was performed in April 2021, via the databases Web of Science and PubMed. The review includes studies of iodine in brown macroalgae in relation to bioavailability, bioaccessibility, processing and speciation. A meta-analysis was conducted in relation to the following topics: (i) the correlation between total iodine and iodide (I^–) content in brown algae; (ii) the correlation between the loss of iodine during processing and the I^– content; and (iii) the correlation between bioavailability and the I^– content. The bioavailability of iodine from brown algae was generally high, with in vivo bioavailability ranging from 31% to 90%. The in vitro bioavailability of iodine (2%–28%) was systematically lower than in vivo bioavailability (31%–90%), indicating an inadequate in vitro methodology. Processing may reduce the iodine content of brown algae, and a higher I^– content was positively correlated with increased iodine loss during processing. Although processing strategies may reduce the iodine content of brown algae significantly, the iodine content may still be high after processing. These findings may be used in food safety evaluations of brown algae as well as in the development of macroalgae-containing foods with iodine contents suitable for human consumption. Further research on processing techniques to reduce the iodine content in brown macroalgae are warranted.     

Effects of elevated iodine in milk replacer on calf performance

Calves were fed milk replacer containing .57, 10, 50, 100, or 200 ppm iodine (from ethylenediaminedihydroiodide) in DM, from 3 to 38 d of age, to estimate the minimum toxic concentration of iodine. Only the 200 ppm iodine intake reduced weight gains, DM intake, feed efficiency, and DM digestibility. At the 100 and 200 ppm iodine intakes, protein digestibility was reduced, and calves showed typical symptoms of iodine toxicity (nasal discharge, excessive tear and saliva formation, and coughing from tracheal congestion). Thyroid iodine increased with every elevation in iodine intake. Iodine in plasma, bile, and non-thyroid tissues started to increase at the 50 ppm intake and, except for muscle, tended to increase again at the 100 and 200 ppm intakes. Thus, the preruminant calf tolerated up to 50 ppm iodine in milk replacer DM for 5 wk postpartum. However, as iodine concentrations in plasma and nonthyroid tissues started to increase at 50 ppm iodine, an upper limit of 10 ppm would be more preferable.     

Effects of iodine intake and teat-dipping practices on milk iodine concentrations in dairy cows

Two studies were conducted to determine the effects of dietary iodine and teat-dipping practices on iodine concentrations in milk. In the first study, 63 cows in mid lactation were assigned to a 3×3 factorial design in which the main effects were dietary iodine levels (0.3, 0.6, and 0.9 mg of dietary I/kg of dry matter) and 3 different postdip managements (chlorhexidine with dip cup, 1% iodine dip cup, and 1% iodine by manual spray). During the 13-d pre-experimental period and the 15-d experimental period, noniodized sanitizers were used in premilking management. During the pre-experimental period, the levels of milk iodine averaged 241.2±5.8 μg/kg, and no relationship was found with lactation number, days in milk, or milk production. Milk iodine concentrations increased linearly with iodine intake. Although teat dipping with 1% iodine had no effect on milk iodine concentration, the same solution applied by spraying greatly increased milk iodine levels. The second study was conducted to determine the effects of udder preparation before milking on milk iodine concentrations. Thirty-two lactating cows were assigned to 4 treatments: no predip (Con); predip with a predip solution containing 0.5% iodine+complete cleaning (Comp); predip with a postdip solution containing 1% iodine+complete cleaning (Post); and predip with a predip solution containing 0.5% iodine+incomplete cleaning (Inc). During the 14-d pre-experimental period and the 19-d experimental period, cows were fed the same diet, and noniodized sanitizers were used for postmilking dipping. During the last week of treatment, milk iodine averaged 164, 189, 218, and 252±9.8 μg/kg for Con, Comp, Post, and Inc, respectively. Preplanned orthogonal contrasts indicated that predipping with a 0.5% iodine predip solution completely wiped off (Comp) tended to increase milk iodine content above that of the control and that the iodine content of Post and Inc were higher than that of the Comp treatment. The results of the first experiment confirm that, to preserve milk safety, iodine should not be fed above requirements. Spraying iodine-based teat-dipping solutions results in large increases in milk iodine content and should be avoided. Predipping teats with an iodine-based sanitizer is an acceptable practice, but must be performed with the appropriate product and completely wiped off before milking.     

Formation of organic iodine supplied as iodide in a soil-water system in Chiba, Japan

Speciation of iodine in a soil-water system was investigated to understand the mechanism of iodine mobility in surface environments. Iodine speciation in soil and pore water was determined by K-edge XANES and HPLC-ICP-MS, respectively, for samples collected at a depth of 0-12 cm in the Yoro area, Chiba, Japan. Pore water collected at a 0-6 cm depth contained 50%-60% of organic iodine bound to dissolved organic matter, with the other portion being I(-). At a 9-12 cm depth, 98% of iodine was in the form of dissolved I(-). In contrast, XANES analysis revealed that iodine in soil exists as organic iodine at all depths. Iodine mapping of soil grains was obtained using micro-XRF analysis, which also indicated that iodine is bound to organic matter. The activity of laccase, which has the ability to oxidize I(-) to I(2), was high at the surface of the soil-water layer, suggesting that iodide oxidizing enzymes can promote iodine organification. The distribution coefficient of organic iodine in the soil-water system was more than 10-fold greater than that of iodide. Transformation of inorganic iodine to organic iodine plays an important role in iodine immobilization, especially in a surface soil-water system.