过氧化氢近红外荧光探针的合成及在食品安全检测中的应用

分别以半花菁和硼酸酯作为荧光母体和识别基团,设计合成了一个过氧化氢荧光探针TC-BOR,其结构通过1HNMR、13CNMR和高分辨质谱(HRMS)进行确证.该探针与过氧化氢反应后的产物(TC-OH)可发射出723 nm的荧光,与加入过氧化氢前相比荧光强度增强约55倍,响应时间不到7 min,最低检测限为2.27μmol...     

长波长过氧化氢荧光探针的合成及在食品安全检测中的应用

分别以半花菁和硼酸酯作为荧光母体和识别基团，设计、合成了一个过氧化氢的荧光探针TC-BOR，并利用1HNMR、13CNMR和HRMS 对其结构进行表征。实验表明，探针与过氧化氢反应后的产物（TC-OH）可发射出723 nm的荧光，荧光强度增强55倍，响应时间低于7 min，检测下限为2.27 μmol·L-1。随后，成功的将TC-BOR用于食品和活细胞中的过氧化氢的定性、定量检测，这可为食品中过氧化氢的快检检测提供一种新方法。     

影响食品添加剂过氧化氢质量要素的探讨

探讨了影响食品添加剂过氧化氢质量的要素。简述了过氧化氢的性质、用途及生产工艺，同时提供了联合国粮农组织（FAO）和世界卫生组织（WHO）食品添加剂联合专家委员会（JECFA）标准、国外标准和中国部分企业标准。最后，逐一地对影响食品添加剂过氧化氢质量的要素进行了探讨。包括过氧化氢含量、不挥发物含量、游离酸含量、磷酸盐含量、铁含量、锡含量、重金属含量、砷含量、稳定度、总碳含量、硝酸根含量。     

A rapid spectrophotometric method for the determination of peroxide value in food lipids with high carotenoid content

A rapid and sensitive ultraviolet-visible spectrophotometric method for determination of peroxide value (PV) in foods with high carotenoid content (e.g., paprika oleoresin, paprika powder, red palm oil) has been developed. The proposed protocol [modified International Dairy Federation (IDF) method] was established from the IDF Fe(II)-oxidation-based spectrophotometric method, and the main one of the introduced modifications consisted of a clean-up extraction step of pigments before determining the PV by complexing Fe(III) ions with thiocyanate. Fe(II) oxidation time, reaction medium, and Fe(III)-thiocyanate complex formation time were optimized. The modified IDF method was compared with and was validated by iodometric AOAC official method with a good correlation (R ²=0.957) between data obtained by both analytical methods. The high sensitivity of the method allows the use of only about 0.010–0.015 g of sample, with a detection limit of 0.044 mequiv peroxide/kg of sample. Therefore, an improved spectrophotometric method for assessing PV in food lipids with high carotenoid content is now available and can be applied to any kind of sample, independent of oil and pigment content.     

The determination of peroxide value by fourier transform infrared spectroscopy

A rapid method for the quantitative determination of peroxide value (PV) of vegetable oils by Fourier transform infrared (FTIR) transmission spectroscopy is described. Calibration standards were prepared by the addition oft-butyl hydroperoxide to a series of vegetable oils, along with random amounts of oleic acid and water. Additional standards were derived through the addition of mono- and diglyceride spectral contributions, as well as zero PV spectra obtained from deuterated oils. A partial least squares (PLS) calibration model for the prediction of PV was developed based on the spectral range 3750–3150 cm⁻¹. Validation of the method was carried out by comparing the PV of a series of vegetable oils predicted by the PLS model to the values obtained by the American Oil Chemists Society iodometric method. The reproducibility of the FTIR method [coefficient of variation (CV)=5%)] was found to be better than that of the chemical method (CV =9%), although its accuracy was limited by the reproducibility of the chemical method. The method, as structured, makes use of a 1-mm CaF₂ flow cell to allow rapid sample handling by aspiration. The spectrometer was preprogrammed in Visual Basic to guide the operator in performing the analysis so that no knowledge of FTIR spectroscopy is required to implement the method. The method would be suitable for PV determinations in the edible oil industry and takes an average of three minutes per sample.     

腐植酸与食品安全

腐植酸是有机高分子化合物，具有多种功能。它与食品安全之间的关系，主要是指与食品生产，即食品生产源头的农业投入品之间关系密切。利用腐植酸开发的农业投入品，可以改善水质，改良土壤，提升肥效，降低药害，保护环境，确保食品生产安全可靠。     

双氧水氧化工艺安全研究策略

国内双氧水绿色氧化工艺蓬勃发展,但工艺本身危险性较高且发生过多起安全事故,严重阻碍了新工艺的开发和推广。为完善工艺安全研究、促进工艺开发,将工艺流程划分为双氧水储存系统、物料进料系统、反应系统、精馏系统等单元,对系统单元涉及的安全问题进行了阐述,总结和探讨了现有研究方法和研究成果。通过对全流程的双氧水氧化工艺中的安全问题和安全研究思路进行梳理分析,为相关工艺开发应用单位建立系统化的安全研究方法和策略、全面提升工艺安全提供建议和参考。     

The importance of corrosion prevention for the safety of chemical plants

One of the most important tasks to eliminate dangers in chemical plants is the prevention of corrosion. This implies the provision of safe enclosures and reaction spaces for the substances to be processed. The present contribution deals with the procedure in the selection of materials for equipment exposed to corrosion and stresses the difficulties connected with the elimination of local corrosion. The relevance of prevention of crack forming corrosion processes is emphasized. Problems to be solved in order to obtain results from investigations, suitable for a safe application of a materials under practical conditions, are indicated.     

浅谈食品添加剂及其对食品安全的影响

阐述了食品添加剂的种类和作用,介绍了我国食品添加剂现状和国内外研究进展,探讨了面粉、奶粉和肉制品等食品中食品添加剂对人体安全的影响。     

Relationship of peroxide value and thiobarbituric acid value to development of undesirable flavor characteristics in fats

The peroxide value and thiobarbituric acid value were compared with the flavor score for a series of different types of fats, with and without added monoglyceride and with and without different stabilizers. The data indicated that the flavor score cannot be estimated for any given fat from either the peroxide value or the thiobarbituric acid value. Either can be used to follow the development of off flavors in a given product or formulation but the relative level may vary from product to product. Presented at the AOCS Meeting in Minneapolis, 1963.     

Determination of peroxide value by conventional difference and difference-derivative spectrophotometry

The spectrophotometric behavior of the system iodide-iodine-iodate-oxygen was studied, and a simple iodometric method to determine peroxide value by conventional, difference or difference-derivative spectrophotometry was developed. The procedures are carried out inside standard photometric cells containing iodide solution to which the sample is added. Absorbance or its first derivative with respect to wavelength is measured to determine iodine concentration by means of calibration curves. No special care to avoid iodide oxidation by atmospheric oxygen is necessary. The method is applicable even to lipids that give emulsions with water, such as phosphatides, and precise results are obtained even at low peroxide values. The use of a digital spectrophotometer with data processing and programming facilities allowed development of an interactive program for automatic operation, which is outlined.     

氧化蜡过氧化价快速测定方法的研究

建立了一种氧化蜡过氧化价的快速测定方法，考察了溶剂、测定温度、反应时间对测定结果的影响。该方法重复性好，相对标准偏差分别为0.2%（氧化石蜡）和0.3%（氧化微晶蜡），可用于测定不同氧化程度的氧化石蜡、氧化微晶蜡的过氧化价，而且该方法具有快速、简便的优点。     

Determination of peroxide value by fourier transform near-infrared spectroscopy

A Fourier transform-near infrared (FT-NIR) method originally designed to determine the peroxide value (PV) of triacylglycerols at levels of 10–100 PV was improved upon to allow for the analysis of PV between 0 and 10 PV, a range of interest to the edible oil industry. The FT-NIR method uses convenient disposable glass vials for sample handling, and PV is determined by spectroscopically measuring the conversion of triphenylphosphine (TPP) to triphenylphosphine oxide (TPPO) when reacted with hydroperoxides. A partial-leastsquares calibration was developed for 8 mm o.d. vials by preparing randomized mixtures of TPP and TPPO in a zero-PV oil. The method was validated with samples prepared by gravimetric dilution of oxidized oil with a zero-PV oil. It was shown that the American Oil Chemists’ Society primary reference method was quite reproducible (±0.5 PV), but relatively insensitive to PV differences at lower (0–2) PV. The FT-NIR method on the other hand was shown to be more accurate overall in tracking PV, but slightly less reproducible (0.9 PV) due to working close to the limit of detection. The sensitivity and reproducibility of the FT-NIR method could be improved upon through the use of larger-diameter vials combined with a detector having a wider dynamic range. The proposed FT-NIR PV method is simple to calibrate and implement and can be automated to allow for routine quality control analysis of edible fats and oils.     

Gauging food and nutritional care quality in hospitals

ABSTRACT: BACKGROUND: Food and nutritional care quality must be assessed and scored, so as to improve health institution efficacy. This study aimed to detect and compare actions related to food and nutritional care quality in public and private hospitals. METHODS: Investigation of the Hospital Food and Nutrition Service (HFNS) of 37 hospitals by means of structured interviews assessing two quality control corpora, namely nutritional care quality (NCQ) and hospital food service quality (FSQ). HFNS was also evaluated with respect to human resources per hospital bed and per produced meal. RESULTS: Comparison between public and private institutions revealed that there was a statistically significant difference between the number of hospital beds per HFNS staff member (p = 0.02) and per dietitian (p < 0.01). The mean compliance with NCQ criteria in public and private institutions was 51.8% and 41.6%, respectively. The percentage of public and private health institutions in conformity with FSQ criteria was 42.4% and 49.1%, respectively. Most of the actions comprising each corpus, NCQ and FSQ, varied considerably between the two types of institution. NCQ was positively influenced by hospital type (general) and presence of a clinical dietitian. FSQ was affected by institution size: large and medium-sized hospitals were significantly better than small ones. CONCLUSIONS: Food and nutritional care in hospital is still incipient, and actions concerning both nutritional care and food service take place on an irregular basis. It is clear that the design of food and nutritional care in hospital indicators is mandatory, and that guidelines for the development of actions as well as qualification and assessment of nutritional care are urgent.     

Uncertainty in assessing the quality of the results of measurements

The quantitative estimation of uncertainty in real experimental variability of the results of measurements and the correspondence of the results obtained to the requirements established was examined. Examples of calculating the uncertainty as a function of the number of measurements, number of laboratories, and standard deviation of the repeatability and reproducibility of the results of the measurements are reported. __________ Translated from Khimicheskie Volokna, No. 4, pp. 66–68, July–August, 2007.     

Monitoring peroxide value in oxidized emulsions by Fourier transform infrared spectroscopy

Soybean oil (SBO) was blended with 10–40% palm kernel olein (PKO) to obtain SBO:PKO blends with different degrees of unsaturation. Oil‐in‐water (O/W) emulsions were then prepared with 70 wt‐% of SBO or SBO:PKO blends and monitored for their chemical destabilization after an accelerated oxidation process up to 12 days at 60 °C. The formation rate of hydroperoxides, as demonstrated by peroxide value (PV) evolution, throughout the oxidation period was relatively high for a fully SBO‐based emulsion as compared to those with PKO incorporation. Fourier transform infrared (FTIR) spectroscopic method was also performed in parallel with PV determination, providing further information on structural changes of the functional groups due to lipid oxidation in the emulsions. By using a partial least square chemometric method, a developed calibration model that was based on the spectral region between 1800 and 1480 cm^?1 was shown to be able to predict the PV in oxidized emulsions over the range of 4–45 meq/kg. With a ‘leave‐one‐out’ cross‐validation optimization procedure, the calibration model provides a good coefficient of determination of 0.98 and a root mean standard error of cross‐validation of 2.09. In general, FTIR spectroscopy is a suitable technique to monitor PV in oxidized emulsions.