Total fat analysis in milk- and soy-based infant formula powder by supercritical fluid extraction

A rapid method for the determination of total fat in infant formula powders using a commercially available supercritical fluid extraction (SFE) instrument was evaluated. The matrices examined were Standard Reference Material SRM 1846 Infant Formula (NIST) and commercial milk- and soybased infant formula powders. Method verification and validation were done by linear regression analysis using the Method of Standard Additions. A Data Quality Objectives (DQO) format was used to define and evaluate the performance characteristic parameters of the instrumental total fat analysis fy SFE. A peer validation study showed excellent agreement with the declared labeled percentage fat values and reproducibility among three participating laboratories. The laboratory relative SD (RSD _R %) is within Horwitz's limits of acceptability and the HORRAT ratio criteria at the level of the analyte analyzed. Linear regression analysis of all infant formula matrices spiked with added fat showed that the SFE instrument response was due only to the added analyte. By integrating the DQO process with a readily available certified reference material, along with reproducibility indicated by two outside collaborating laboratories, we established verification and validation of the accuracy of the data obtained by SFE.     

微波消解-FAAS检测婴幼儿奶粉中重金属元素

通过微波消解-火焰原子吸收光谱法(FAAS)检测婴幼儿奶粉样品中的铅、铬、铜、钴、锌5种重金属元素含量。对仪器工作条件进行优化,测定的相对标准偏差(RSD)为0.036 1%~5.647%,回收率为97.2%~105.3%。     

微波消解-FAAS检测婴幼儿奶粉中重金属元素

通过微波消解-火焰原子吸收光谱法(FAAS)检测婴幼儿奶粉样品中的铅、铬、铜、钴、锌5种重金属元素含量。对仪器工作条件进行优化,测定的相对标准偏差(RSD)为0.036 1%⁵.647%,回收率为97.2%5.647%,回收率为97.2%¹05.3%。     

Determination of fat content by the Caviezel® method (rapid method)

The "Joint Committee for the Analysis of Fats, Oils, Fatty Products, Related Products and Raw Materials (GAFett)" has developed the following method for the determination of fat content. It is intended to include this method in Section C, Chapter III of the German Standard Methods³     

Fully automated determination of solid fat content by pulsed NMR

Pulsed NMR has been developed into a quick, accurate fully automated method for the determination of the solid fat content in partially crystallized fats. Accepting a standard deviation of 0.3% solids, the percentage of solids is displayed on a digital voltmeter or printed out 6 sec after placing the sample into the sample holder. To allow for the dead time of the receiver, a correction factor has been introduced giving rise to only small errors (<1%) in the solid fat content. Due to the short measuring time, no temperature control of the sample holder is needed between 10–45 C. Pulsed NMR values can be converted into dilatations and vice versa.     

Quantitative determination of medium chain triglycerides in infant formula by reverse phase HPLC

Two methods were developed for the separation of medium chain triglycerides (MCT) using reverse phase HPLC. Both methods employed a C18 microbond HPLC column as the stationary phase and an isocratic solvent system. The first method described consists of acetonitrile/acetone as the mobile phase with a differential refractometer as the detector. In the second method, acetonitrile/water was used as the mobile phase and a UV detector at 210 nm. Trinonanoin was used as the internal standard for quantitative determination. This method is suitable for milk-, whey- and soy protein-based matrices. With minor modification, it is applicable to MCT levels ranging from 10 to 50% of total fat.     

用正交试验法确定复合水泥配方

用正交试验法研究了以沸石和石灰石生产复合水泥的原料选择及最佳掺量,借助XRD和SEM等测试手段,对水泥水化产物和微观结构进行了分析。结果表明：正交试验法可以较好地应用于复合水泥配方的制定,为水泥企业生产不同称号的复合水泥提供可靠的理论依据。     

Effect of infant formula with probiotics on intestinal microbiota

Weaning during infancy refers to the initiation of complementary food to breast milk. During weaning, there are significant changes on the gastrointestinal microbiota. Deleterious alterations of the gastrointestinal microbiota can result in pathological processes while measures that stimulate its development and stability, like the use of probiotics, are beneficial. The mechanisms by which probiotics achieve their effects have not been clearly established. Present work compares the microbial composition of feces from infants that were weaned to regular family food, formula with probiotics (B. Lactis BL y S. Thermophilus) or formula without probiotics. Accordingly, analysis of rDNA of microbial fecal samples by molecular techniques was used. Formula with or without probiotics was well tolerated and safe for all participating children. Probiotics present in formula were viable and susceptible to culture. There was not difference on physical growth or development among all participants. The microbiota of children supplemented with formula with- or without probiotics was different than that observed in children supplemented with regular food. It was not possible to determine enrichment of B. Lactis BL and S. Thermophilus in the feces of children that consumed the probiotics. Present work contributes to the understanding of probiotics effects in human health.     

Determination of fat composition

A revolution has taken place in the analysis of fats. Physical methods, both rapid and accurate, have replaced laborious chemical procedures. The timehonored saponification equivalents and iodine values now are calculated from Chromatographic and nuclear magnetic resonance spectroscopic data. Differential migration processes such as countercurrent distribution, liquid-liquid chromatography, and gas chromatography have supplanted the classical distillation and crystallization procedures for analysis and preparation. What have been referred to as “gadgets” are now the stock-in-trade of the analytical lipid chemist. Mass, infrared, ultraviolet, and nuclear magnetic resonance spectrometers are the accepted tools for organic characterization. Recording detectors and computer processing of data reduce the labor of analysis and improve its quantitation. Today’s methodology stands at the verge of specifying fatty acid composition of even so complex lipids as hydrogenated fats in terms of the amounts, the positions, and geometric configurations of its individual component fatty acids. Presented at the AOCS Short Course, East Lansing, Mich., Aug. 29-Sept. 1, 1966. No. Utiliz. Bes. Dev. Div., ARS, USDA.     

毛氏提取法测定液体乳制品中脂肪含量

建立了毛氏提取法测定液体乳制品中脂肪的方法,并分析了不同方法的系统性差异。建立的方法与GB5409—1985中罗兹哥特里法比较,具有准确、精密度高、易于操作的优点,能满足液体乳制品中脂肪的测定要求。     

Determination of particle shape distribution of clay using an automated AFM image analysis method

We have developed a direct imaging method for measuring particle shape distributions. It consists of a series of advanced automated algorithms that analyze 3D Atomic Force Microscopy (AFM) images of diluted pigment suspensions deposited onto glass cover slips. The method was applied to determine particle shape distributions of 10 different clay pigments from Brazil and Georgia, US. We found that the aspect ratio varies significantly and monotonically with particle diameter. The method gives generally lower average aspect ratios than those mentioned in previously published data, but still ranks pigments similarly. It was determined that Georgia clays generally have higher aspect ratios and broader shape distributions than Brazilian clays. This new direct automated AFM image analysis approach will be useful in pigment shape characterization and will provide important data for predicting coated paper performance.     

Nutritional balance studies: evaluation of a premature infant formula

A 24 kcal/oz (81 kcal/100 ml) premature infant formula (Enfamil Premature Formula) with moderately high mineral content (117 mg Ca/100 ml and 58 mg P/100 ml) and a protein content of 3 g/100 kcal was evaluated in sixteen 3-day balance studies at 10 and 21 days of age in nine premature infants with birth weights from 1,200 to 1,400 g. Growth rates were similar to in utero rates, and the formula was well accepted and tolerated. Calcium retention (62.5%) was similar to in utero accretion, and phosphorus retention was only slightly lower. Nitrogen retention was high without the development of metabolic acidosis or abnormal serum urea nitrogen levels.     

Determination of solid fat index by fourier transform infrared spectroscopy

A unique and rapid Fourier transform infrared (FTIR) spectroscopic method for the determination of solid fat index (SFI) of fats and oils was developed, which is capable of predicting the SFI profile of a sample in approximately two minutes, without the need for tempering. Hydrogenated soybean oil samples (n=72), pre-analyzed for SFI by dilatometry, were melted and their FTIR spectra acquired using a 25 μm NaCl transmission flow cell maintained at 80°C. Approximately half the samples were used for calibration, with the balance used as validation samples. Partial least squares (PLS) calibrations were developed from selected spectral regions that are associated with thecis, trans, ester linkage and fingerprint regions of the spectrum and related to the dilatometric SFI values obtained at 50, 70, 80, and 92°F. The calibrations were initially optimized and cross-validated by using the “leave one out” approach, with the accuracy and reproducibility of the calibration models assessed by predicting the validation samples. The overall cross validation accuracy of the PLS calibration models was in the order of ±0.71 SFI units over the four temperatures. Week-to-week validation accuracy and reproducibility was determined to be ±0.60 and ±0.38 SFI units, respectively, the reproducibility being within the specifications associated with the dilatometric reference method. To facilitate routine “on-line” FTIR analyses, a Visual Basic program was written to drive the spectrometer, prompt the user to load the sample, calculate, and print the SFI values determined from the PLS calibrations. As structured, the FTIR method has the potential to serve as a viable substitute for the traditional dilatometric SFI method, with the elimination of the tempering step reducing analysis time from hours to minutes. The FTIR approach should also be applicable to the determination of solid fat content if calibrated against solids data obtained by nuclear magnetic resonance.     

婴幼儿奶嘴中12种N-亚硝胺类物质迁移量检测的研究

建立了婴幼儿奶嘴中12种N-亚硝基胺类物质迁移量的气相色谱-质谱联用检测方法。 样品经人工唾液盐浸提后,以二氯甲烷为溶剂萃取浸提液中的N-亚硝胺,去水浓缩后,用气相色谱-质谱联用仪进行测定,外标法定量。结果表明,方法的定量限为0.027mg/L～0.031mg/L,回收率为86.9%～120%,相对标准偏差为4.25%～8.31%,应用本方法对21 个国内外品牌的婴幼儿奶嘴进行了测试,其中16 个样品中检出了N-亚硝胺。     

醇解法测定PEN中二甘醇含量

PEN用甲醇醇解,生成的萘二甲酸二甲酯过滤除去,解离出的DEG用气相色谱法测定。     

化学发光分析法测定沙拉沙星的研究

Tb^3＋能够增强Ce^4＋-H2SO3-沙拉沙星体系化学发光强度,据此建立了测定沙拉沙星的流动注射化学发光新方法,该法快速、简单、灵敏度高、选择性好。其线性范围为1.5×10^-8-5.0×10^-4g/mL,检出限为8.3×10^-9g/mL,相对标准偏差（n=11,c=2.5×10^-5g/mL）为2.2%。利用该法测定了盐酸沙拉沙星注射液中沙拉沙星的含量,回收率为95.1%-101.4%。     

Determination of molecular formula and stereoconfiguration of unique steroids by X-ray diffraction analysis

X-Ray diffraction analyses can determine chemical composition, molecular formula and stereoconfiguration and can provide geometric parameters with uncertainties for bond distances of the order of 0.01 Å and for bond angles of the order of 1°. These analyses are especially useful when the substance analyzed is present only in very small quantities and is of uncertain composition or molecular formula. Only one suitable crystal is required for the analysis to proceed. There are many instances in which such circumstances have prevailed in the diffraction analysis of steroids. Among the examples given here is a new type of natural plant hormone with profound growth-stimulating capabilities when applied in nanogram quantities per plant. The structure determination of this substance has greatly facilitated attempts to synthesize it and thereby to derive sufficient quantities for widespread testing.