加碘盐生产过程中碘含量不稳定的探讨

从生产环节控制的角度,对加碘盐中碘含量不稳定现象产生的原因进行了分析,提出了在生产过程中消除碘含量不稳定现象的方法和措施。     

Adding an oxidant increases the stability of iodine in iodized salt

It has been shown that moisture plays a critical role in the stability of iodine and that reducing agents in iodized salt reduce the stability of iodine. We question whether this is valid in all cases, and have found that the reducing agent may play a more important role than moisture in decreasing the stability of iodine. We reviewed current methods to enhance iodine retention in iodized salt, and propose methods to produce stable iodized salt and to analyze its stability. Our experiments showed that when reducing impurities are removed, iodine remains stable in iodized salt, even when the salt is "wet." We suggest that the stability of iodine in iodized salt can be improved by oxidizing iodized salt with sodium hypochloride, and that the iodine content of iodized salt, after heating at 120 degrees C for one hour, can be used to reflect the quality of iodized salt. We have demonstrated that reducing agents play a critical role in the stability of iodine in iodized salt. We have shown a method of purifying salt by removing reducing materials, which can be used to produce iodized salt with sufficient stability at lower cost. We also propose an analytical method to determine the stability of iodine in iodized salt. These methods could be further developed to achieve better accuracy, precision, and reliability and be applied to a greater variety of iodized salts.     

Stability of iodine in salt fortified with iodine and iron

BACKGROUND: Determining the stability of iodine in fortified salt can be difficult under certain conditions. Current methods are sometimes unreliable in the presence of iron. OBJECTIVE: To test the new method to more accurately estimate iodine content in double-fortified salt (DFS) fortified with iodine and iron by using orthophosphoric acid instead of sulfuric acid in the titration procedure. METHODS: A double-blind, placebo-controlled study was carried out on DFS and iodized salt produced by the dry-mixing method. DFS and iodized salt were packed and sealed in color-coded, 0.5-kg, low-density polyethylene pouches, and 25 of these pouches were further packed and sealed in color-coded, double-lined, high-density polyethylene bags and transported by road in closed, light-protected containers to the International Council for the Control of Iodine Deficiency Disorders (ICCIDD), Delhi; the National Institute of Nutrition (NIN), Hyderabad; and the Orissa Unit of the National Nutrition Monitoring Bureau (NNMB), Bhubaneswar. The iodine content of DFS and iodized salt stored under normal room conditions in these places was measured by the modified method every month on the same prescribed dates during the first 6 months and also after 15 months. The iodine content of DFS and iodized salt stored under simulated household conditions was also measured in the first 3 months. RESULTS: After the color code was broken at the end of the study, it was found that the DFS and iodized salt stored at Bhubaneswar, Delhi, and Hyderabad retained more or less the same initial iodine content (30-40 ppm) during the first 6 months, and the stability was not affected after 15 months. The proportion of salt samples having more than 30 ppm iodine was 100% in DFS and iodized salt throughout the study period. Daily opening and closing of salt pouches under simulated household conditions did not result in any iodine loss. CONCLUSIONS: The DFS and iodized salt prepared by the dry-mixing method and stored at normal room conditions had excellent iodine stability for more than 1 year.     

Iodine nutrition: iodine content of iodized salt in the United States

Adequacy of iodine nutrition in the United States has lately been of concern. A major source of dietary iodine for the U.S. population is iodized salt. The U.S. Food and Drug Administration (USFDA) recommends 60-100 mg Kl/kg salt, equivalent to 46-76 mg l/kg salt. All U.S. iodized salt contains 45 mg l/kg according to labels. We collected samples of table salt from freshly opened containers from U.S. volunteers. A sample was sent to us when the can was first purchased. Subsets of volunteers sent further samples when the salt container became half-empty through normal use and a further final sample when the container was nearly finished. We also looked at iodine distribution homogeneity within individual containers, loss of iodine from salt upon exposure to humidity and sunlight, and upon short-term heating (dry and in solution) as may be encountered in cooking. Measurements were made in 0.01% w/v salt solutions by induction coupled plasma-mass spectrometry with 72Ge as an internal standard. The median and mean (+/-sd) I content in freshly opened top-of-the-can salt samples was 44.1 and 47.5 +/- 18.5 mg/kg (n=88, range 12.7-129 mg l/kg) and geometric mean and standard deviation of 44.70 and 1.41. Forty-seven of 88 samples fell below the USFDA recommended I content while 6 exceeded it. The homogeneity in a single can of salt varied greatly: in 5 samples taken from the same container from different depths, the iodine content varied by as little as 1.2x (8.3% coefficient of variance (CV)) to as much as 3.3x (49.3% CV) from one container/brand to another. Iodine is significantly lost upon high humidity storage but light or dry heat has little effect. There is much recent literature on iodine sufficiency and uptake inhibitors; there is also much misinformation and disinformation. We review the relevant literature and discuss our results with reference to the United States.     

2004～2013年湖南省加碘食盐碘含量检测结果与分析

检测湖南省加碘食盐碘含量,为碘缺乏病的消除及防治提供科学决策依据。根据GB/T 8618—2001《制盐工业主要产品取样方法》取样和《食盐卫生标准》检测,2004~2013年每年每个季度在全省14个地级市各大型超市抽取不同品种的加碘食用盐样品。结果表明:2004~2013年共抽取和检测加碘食用盐样品1 680份,加碘食盐碘含量平均值为27.31~33.98 mg/kg,加碘食盐中碘含量中位数为27.58~33.70 mg/kg,符合GB 5461—2000和GB 26878—2011中关于碘含量的规定。加碘食盐中碘含量合格率为95.55%~100%,且呈稳步提高趋势。     

烹饪调味过程对加碘盐补碘效率的影响

本文在常规烹饪盐咸味的调味过程中,分别用斯柯维法、P*S蓝光度法测定食物盐咸味的调味效果及加碘盐的碘损失情况,分析烹饪调味过程对加碘盐补碘效率的影响。     

Stability of bioactive solid lipid nanoparticles loaded with herbal extracts when exposed to simulated gastrointestinal tract conditions

Solid lipid nanoparticles (SLN) can be used as vehicles for phenolic compounds rich extracts. In the present work two types of waxes — witepsol and carnauba were tested for the first time in the production of solid lipid nanoparticles (WSLN and CSLN, respectively) loaded with sage and savoury extracts. Physical characterization and association efficiencies calculation were performed. Discrimination of loaded phenolic compounds from each extract was made using HPLC assays. Antioxidant activities of SLN were characterized using two different methods — ABTS and ORAC. Finally, the phenolic compound release profile from SLN and stability when exposed to simulated gastrointestinal tract (GIT) conditions were also evaluated. Different phenolic compounds from sage and savoury extracts were entrapped in SLN. The highest antioxidant activity was obtained for the SLN loaded with savoury extract. Stomach simulated condition provokes a partial release of rosmarinic acid from SLN, whereas at small intestine simulation step, all SLN showed a release of ca. 100%. Witepsol SLN were the ones that best maintained their physical integrity during digestion, showing to be the most stable vehicles for sage and savoury extracts. These SLN show to be suitable for the production of food functional ingredients bearing antioxidant activity.     

Investigation of iodine bioavailability from chicken eggs versus iodized kitchen salt with in vitro method

The goal of the presented studies was to investigate speciation and bioavailability of iodine from chicken eggs versus iodized kitchen salt with an in vitro method. Determination of iodine total content in chicken eggs and iodized kitchen salt was carried out by inductively coupled plasma mass spectrometry (ICP MS). The majority of iodine was accumulated in the yolk—the concentration was even 37 times higher than in white. Chicken eggs were treated with buffer (Tris HCl pH = 7.5) and enzymatic extraction media and analyzed by size exclusion chromatography hyphenated with inductively coupled plasma mass spectrometry (SEC ICP MS). The enzymatic extraction being an in vitro bioavailability assessment method was based on two-stage digestion model simulating gastric (pepsin digestion) and intestinal (pancreatin digestion) juices. Speciation analyses along with bioavailability studies presented iodide as the major form in chicken eggs. The bioavailability was established as 33% from white and 10% from yolk and decreased with longer time of boiling. It allows to suggest that the majority of iodine remains in forms bound to non-digestible coagulated and water-insoluble proteins.     

The production of aflatoxins in fresh date fruits and under simulated storage conditions

Sixteen varieties of date fruit (Phoenix dactylifera) at three stages of maturation (Kimri, Rutab and Tamr) were examined for the presence of fungi and analysed for aflatoxins B₁, B₂, G₁ and G₂ and sterigmatocystin. Single samples of each variety were used in the study. Samples as received were initially examined for mycoflora and toxin levels and then stored at 98% relative humidity and 30 °C for 14 days to investigate the effects of possible adverse storage conditions on mycoflora and, in particular, aflatoxin formation. All samples showed an absence of aflatoxins and their precusor, sterigmatocystin, after adverse storage for 14 days, although aflatoxin‐producing Aspergillus flavus isolates were identified in 10 varieties at the first stage of maturation (Kimri). High fungal counts were associated with the Rutab stage and low counts with the Tamr stage. The counts of A flavus ranged from 5.00 to 8.16 log₁₀(cfu g^?1) under simulated storage conditions, and three varieties contained significant levels of aflatoxin B₁ or B₂ ranging from 35 to 11 610 µg kg^?1. Sterigmatocystin was not detected in any of the samples as received or under simulated storage conditions. © 2002 Society of Chemical Industry     

Protective effect of whey cheese matrix on probiotic strains exposed to simulated gastrointestinal conditions

A probiotic whey cheese added with Lactobacillus casei LAFTI®L26, Lactobacillus acidophilus LAFTI®L10 or Bifidobacterium animalis Bo was subject in vitro to sequential conditions that parallel the four major steps of digestion: mouth (artificial saliva), oesophagus-stomach (artificial gastric juice), duodenum (artificial intestinal juice) and ileum; its manufacture followed the traditional cheesemaking protocol of Portuguese Requeijão. MRS broth was inoculated in parallel as reference medium, to ascertain the protective effect of the whey cheese matrix itself upon those strains in every digestion step. Mouth conditions had an almost negligible effect upon all three strains, whereas oesophagus-stomach, duodenum and ileum conditions decreased the viable numbers of L. casei and L. acidophilus; in both systems, B. animalis suffered only slight decreases in viable numbers; and L. casei and L. acidophilus behaved likewise in MRS exposed to duodenum and ileum conditions. Whey cheese matrices thus appeared to protect the aforementioned three strains during transit throughout the simulated gastrointestinal system, so they are promising carriers of those probiotic bacteria.     

食用加碘绿标盐结块原因分析与措施

食用加碘绿标盐2012年投放市场以来,因产品存在着不同程度的结块,影响产品的分装和市场销售,制盐生产企业为此进行不懈的调试,但收效甚微。井神盐化公司二分公司是国家食盐生产定点企业,满足人民生活需要是生产第一要务,通过一系列的生产和过程控制调试,绿标盐结块现象明显好转,既满足市场需要,又提高企业经济效益。     

含乙二胺四乙酸铁钠碘盐中碘含量的测定

介绍一种对含乙二胺四乙酸铁钠碘盐中碘含量的测定方法。通过实验证明，该方法操作简单，准确可行。     

碘盐直销模式的实践与思考

随着盐业体制改革的逐渐明朗化,各盐业公司如何应对成为研究方向。本文以盐城地区为例,介绍了碘盐直销模式,从管理到考核,提出了整合资源、抓大放小、打造品牌、区域代理等经营管理方法。     

精制食盐及加碘精制食盐营养健康效应的对比实验评价

目的采用小鼠模型及损益指数及总积分(benefit damage index-general score, BDI-GS)系统对比评价市售精制食盐及加碘食盐的营养健康效应,揭示其过度摄取的健康危害。方法生长期雄性ICR实验小鼠分为7组,分别是玉米空白对照组,0.5%、1.0%、1.5%精制食盐及0.5%、1.0%、1.5%加碘盐实验组,每组各8只小鼠。总计喂养10d,隔日称取体质量1次。第10d取血分离血清,处死小鼠并解剖。准确称取心、肺、胸腺、脾、肝脏、胰腺、双肾、性腺及股骨质量;血清测定常规血生化指标,并进行统计学分析。结果精制食盐组小鼠胰腺的营养及健康指标BDI均小于等于0.90。加碘食盐小鼠之胰腺营养健康损害更严重,个别剂量BDI甚至低至0.67,并且统计学与空白对照组存在显著性差异(P0.05)。加碘食盐对性腺营养健康存在较重损害,各剂量组BDI均明显低于1.0。结论精制食盐过度摄取对人体营养健康会造成不利影响,加碘食盐存在一定健康问题。     

Determination of iodine concentration in salt dual fortified with iron and iodine

The applicability of the iodide catalyzed reaction (Sandell-Kolthoff) between Ce⁴⁺ and As³⁺ for the determination of iodine in salt samples fortified with iron and iodine has been studied. A method verification program is presented; the catalytic method was compared with isotope dilution inductively coupled plasma-mass spectrometry (ICP-MS), for which the long-lived iodine nuclide ¹²⁹I was used. Two-way analysis of variance (ANOVA) revealed that both methods yielded consistent iodine results across salt samples from Morocco and the Ivory Coast that were either free of iron or fortified with different iron species. Although some bias was present, no influence of iron on the catalytic reaction was detected.     

微分脉冲伏安法测定加碘盐中碘酸根离子

报道了运用微分脉冲伏安法测定食盐中碘酸根含量的方法。在1.0mol/LNaCl,pH=12的介质中,当脉冲振幅为70mV,脉冲周期为0.2s时,碘酸根离子在微分脉冲伏安图上出现一个灵敏的微分脉冲伏安峰,峰电位为-1.30V(vs.Ag/AgCl),峰电流与碘酸根离子浓度在2.0×10-7～1.0×10-5mol/L范围内成良好的线性关系,相关系数为0.9995,方法检出限为1.0×10-7mol/L。方法已用于加碘食盐中碘酸根含量的测定,平均回收率为100.7%。循环伏安(CV)测试表明,碘酸根在汞膜电极上电化学反应是不可逆过程。     

理论加碘量对碘盐批质量的影响

通过计算，探讨了理论加碘量对碘盐批质量的影响，提出生产厂家在控制理论加碘量时应注意的一些问题。