Use of NIRS technology with a remote reflectance fibre-optic probe for predicting major components in cheese

In the present work the potential of near infra-red spectroscopy technology (NIRS) together with the use of a remote reflectance fibre-optic probe for the analysis of fat, moisture, protein and chlorides contents of commercial cheeses elaborated with mixtures of cow's, ewe's and goat's milk and with different curing times was examined. The probe was applied directly, with no previous sample treatment. The regression method employed was modified partial least squares (MPLS). The equations developed for the cheese samples afforded fat, moisture, protein, and chloride contents in the range 13-52%, 10-62%, 20-30%, and 0.7-2.9%, respectively. The multiple correlation coefficients (RSQ) and prediction corrected standard errors (SEP (C)) obtained were respectively 0.97 and 0.995% for fat; 0.96% and 1.640% for moisture; 0.78% and 0.760% for protein, and 0.89% and 0.112% for chlorides.     

Elemental Analysis and Metal Intake of Romanian Vegetables

ABSTRACT

Inductively coupled plasma-mass spectrometry multielemental profiling was performed to determine eight elements in 54 vegetable samples. The range of concentrations of Fe and Ni was 1.91?±?0.09 to 443.31?±?22.32?mg/kg and 0.05?±?0.004 to 16.36?±?0.36?mg/kg, respectively. The concentrations of Pb and Cd were up to 1.56?±?0.04 and 0.78?±?0.04?mg/kg, respectively. Some samples exceeded the maximum admissible limits imposed by national and international regulations. The mean concentrations of Mn and Cu were between 20.93?±?0.43 and 13.98?±?0.30?mg/kg in tomatoes and 20.60?±?0.53 and 11.25?±?0.22?mg/kg in peppers. For the evaluation of health risk related to the consumption of vegetables, the daily intake rate, target hazard quotient (THQ), and hazard index were evaluated. The daily intakes were low and correspond to 2 to 14% of the tolerable daily values established by legislation. The results showed that the THQ and hazard index for the metals were lower than 1, indicating that the vegetable ingestion does not represent a significant risk for consumer health. Analysis of variance revealed that Zn may be used as a species-specific marker (p?=?0.026). Principal component analysis extracted three main components, explaining a total variance of 72.49% and grouped all determined elements.     

Determination of furfural in beers,vinegars and infant formulas by solid-phase microextraction and gas chromatography/mass spectrometry

The solid-phase microextraction (SPME) technique with on-fibre derivatisation was evaluated for the analysis of furfural in infant formulas, beers, and vinegars. The poly(dimethylsiloxane)/divinylbenzene (PDMS/DVB) fibre was used and O-2,3,4,5,6-(pentafluorobenzyl)hydroxylamine hydrochloride (PFBHA) was first loaded onto the fibre. Food sample of 2?mL was then placed in a 4?mL PTFE-capped glass vial. Headspace extraction by the SPME fibre was performed at 80°C for 20?min under 1100?rpm magnetic stirring with the addition of 40% sodium chloride. Afterwards, the SPME fibre was directly desorbed at the injection port of a gas chromatography/mass spectrometer (GC/MS), followed by the analysis of derivatives formed on-fibre. To avoid matrix interferences, standard addition method was performed. The adsorption-time profiles were examined. The precision, recovery and method detection limits (MDLs) were evaluated with spiked food samples. The relative standard deviations from different spiked samples were all less than 5% and the recoveries were 100?±?5%. With 2?mL of food sample, MDLs were in the range of 3.09?～?14.05?µg?L^?1. Compared with other techniques, the study shown here provided a simple, fast and reliable method for the analysis of furfural in food samples.     

Construction of an Isoperibol Calorimeter to Measure the Specific Heat Capacity of Foods Between 20 and 90°C

A simple isoperibol calorimeter, using the modified method of mixtures, was developed to measure the average specific heat capacity of different dough types between 20 and 90°C. The method consisted of encapsulating the sample in a copper cylinder and immersing the capsule in water at a different temperature. The procedure was tested for reliability with distilled water and whole fat milk before applying it to five dough types of varying moisture and fat contents. Mean values of 4.176±0.008 kJ kg^-1 K^-1 and 3.942±0.034 kJ kg^-1 K^-1 were obtained for distilled water and milk respectively, which agree within 0.23 and 0.34% from reported values. The specific heat values for the five dough types were found to range between 2.15–2.68 kJ kg^-1 K^-1 between 2.35–3.10 kJ kg^-1 K^-1 and between 2.40–3.19 kJ kg^-1 K^-1 at the three temperature levels studied. The specific heat capacity was found to depend not only on the moisture level but also on the fat content, especially for dough types with a high percent of fat. Regression analysis was then used to correlate these values and develop a set of empirical equations. The results were used to assist in energy balance calculations in backing oven for industrial purposes. This revised version was published online in July 2006 with corrections to the Cover Date.     

Natural <Superscript>3</Superscript>H radioactivity analysis in groundwater and estimation of committed effective dose due to groundwater ingestion in Varahi and Markandeya river basins,Karnataka State,India

The present study aimed at the assessment of natural tritium radioactivity in groundwater, being used for domestic and irrigation purposes in Varahi and Markandeya river basins. The study also intended to assess human health risk by estimating committed effective dose due to groundwater ingestion in the study area, taking into consideration the obtained tritium activity concentrations and annual water consumption. Tritium concentration of groundwater samples from the Varahi and Markandeya river basins were determined by liquid scintillation counting and the results laid in the range of 1.95 ± 0.25 to 11.35 ± 0.44 TU and 1.49 ± 0.75 to 9.17 ± 1.13 TU in Varahi and Markandeya river basins, respectively. Majority of the samples from Varahi (46.67%) and Markandeya (62.5%) river basins belong to modern water category aged between 5 and 10 years, while the remaining 53.33% and 37.5% of the samples from Varahi and Markandeya river basins respectively belong to sub-modern water with modern recharge, significantly influenced by precipitation and river inflowing/sea water intrusion. The effective committed dose for general public consumption considering the highest concentration value of 0.02 μSv year⁻¹, which is very negligible compared to EPA (0.04 mSv year⁻¹), WHO (0.1 mSv year⁻¹), ICRP (1.0 mSv year⁻¹) and UNSCEAR (2.4 mSv year⁻¹) recommended dose limits, should not mean any additional health risk for the population living nearby.     

Seasonal variations of volatile constituents of Hemizygia bracteosa (Benth.) Briq. aerial parts from Benin

Essential oils from fresh aerial parts of Hemizygia bracteosa (Benth.) Briq. were extracted by steam distillation. The oil yield from plants collected during the hot season (February) and during the cold season (August) were 0.12 ± 0.01% and 0.25 ± 0.02%, respectively. GC/FID and GC/MS analyses allowed us to identify a total of 65 compounds, representing 97% of the hydrodistillate. The main components of the oil from the hot period were (E)-β-farnesene (64 ± 0.04%), β-elemene (7.4 ± 0.05%), trans-nerolidol (6.2 ± 0.04%), and α-muurolene (2.7 ± 0.03%). The essential oil from the cold season was characterized by the presence, as major compounds, of (E)-β-farnesene (67 ± 0.04%) along with β-caryophyllene (3.6 ± 0.06%), β-elemene (3.3 ± 0.05%), 7-epi-α-selinene (3.1 ± 0.01%) and p-cymene (2.5 ± 0.04%). This is the first report of these components in the essential oil of Hemizygia bracteosa (Benth.) Briq.     

Comparison of two infrared spectroscopic methods for cheese analysis

Two infrared spectroscopic methods, optothermal near infrared (NIR) spectroscopy and Fourier transform mid-infrared-attenuated total reflection (FTIR-ATR) spectroscopy, were applied to 24 cheese samples in order to obtain protein, fat and moisture contents. Reference values of the protein, fat and moisture contents in weight percent were obtained using standard wet chemistry analysis. Prediction correlation coefficients between 0.93 and 0.96 and standard errors of prediction between 2% and 5% were obtained using optothermal spectroscopy while the corresponding values for FTIR-ATR were 0.81–0.92 and 4–9%. Inhomogeneities in the cheeses, primarily due to the fat droplets, are probably the main reason for the differences in the error sizes. The superior results for optothermal spectroscopy are the more attractive because the instrument is easier to use than the FTIR-ATR instrument, it provides results more quickly with simpler statistical analysis and it is more compact and robust.     

Gas-phase reaction of ozone with trans-2-hexenal,trans-2-hexenyl acetate,ethylvinyl ketone,and 6-methyl-5-hepten-2-one

The gas-phase reaction of ozone with the unsaturated oxygenates trans-2-hexenal, trans-2-hexenyl acetate, ethylvinyl ketone, and 6-methyl-5-hepten-2-one, which are components of biogenic emissions and/or close structural homologues thereof, has been investigated at atmospheric pressure and ambient temperature (286–291 K) and humidity (RH = 55 ± 10%). Reaction rate constants, in units of 10⁻¹⁸ cm³ molecule⁻¹ s⁻¹, are 1.28 ± 0.28 for trans-2-hexenal, 21.8 ± 2.8 for trans-2-hexenyl acetate, and 394 ± 40 for 6-methyl-5-hepten-2-one. Carbonyl product formation yields, measured with sufficient cyclohexane added to scavenge the hydroxyl radical, are 0.53 ± 0.06 for n-butanal and 0.56 ± 0.04 for glyoxal from trans-2-hexenal, 0.47 ± 0.02 for n-butanal and 0.58 ± 0.14 for 1-oxoethyl acetate from trans-2-hexenyl acetate, 0.55 ± 0.07 for formaldehyde and 0.44 ± 0.03 for 2-oxobutanal from ethylvinyl ketone, and 0.28 ± 0.02 for acetone from 6-methyl-5-hepten-2-one. Reaction mechanisms are outlined and the atmospheric persistence of the compounds studied is briefly discussed. © 1996 John Wiley & Sons, Inc.     

Formation of free radicals in photoirradiated cellulose. II. Effect of moisture

The effect of moisture content upon free radical formation in celluloses irradiated with ultraviolet light has been studied by means of ESR spectroscopy at 77°K. As studied from the variation of the line-shape and the relative signal intensity of the spectra observed, it is clear that moisture content in the sample greatly influences the formation of free radicals when irradiated with ultraviolet light. The moisture content in the range of 5–7% leads to a significant decrease of radical formation; and alternatively, when moisture content is lower or higher than this range, the formation of free radicals is increased.     

Synthesis of the enantiomers of cis-2-methyl-5-hexanolide,the major component of the sex pheromone of the carpenter bee

(2R,5S)-2-Methyl-5-hexanolide and its antipode were synthesized in highly optically pure state (?98–99% e.e.) starting from ethyl (S)-lactate and the enantiomers of methyl β-hydroxyisobutyrate. The specific rotations of our samples were [α]_D±91.0-93.5° (CHCl₃), while the reported values of the samples prepared by resolution or asymmetric synthesis were ±64.5–65.6°.     

PDMS extraction bars for the determination of volatile aromatic hydrocarbons in water and wastewater

In this study, the preparation and application of extraction bars of PDMS were investigated to preconcentrate and determine benzene, toluene, ethylbenzene, and xylene in water and wastewater by means of HPLC with fluorescence detection. Aliquot samples from hospital wastewater were used as the model effluent. The independent variables for the sorptive extraction were as follows: ionic strength (added amounts of NaCl); pH; temperature and time of absorption; temperature and time of desorption. Under optimized conditions, by using a factorial design, the suspended extraction bars could allow the determination of benzene, toluene, ethylbenzene, and xylene (1.20 ± 0.05 μg/L; 10.40 ± 0.02 μg/L; 1.80 ± 0.04 μg/L; 15.9 ± 0.04 μg/L, respectively) in hospital effluent (fortified samples), by recoveries of 71.9 ± 4.9 to 74.8 ± 5.6%. This procedure represents an innovation that eliminates the time‐consuming stage of vacuum microfiltration, and allows the determination of volatile organic compounds by HPLC. As far as we know, this procedure is original and represents an important contribution to the field.     

Influence of gamma irradiation and storage on the microbial load,chemical and sensory quality of chicken kabab

Influence of gamma irradiation and storage on the microbial load, chemical and sensory quality of chicken kabab was investigated. Chicken kabab was treated with 0, 2, 4 or 6 kGy doses of gamma irradiation. Treated and untreated samples were kept in a refrigerator (1–4 °C). Microbiological, chemical and sensory characteristics of chicken kabab were evaluated at 0–5 months of storage. Gamma irradiation decreased the microbial load and increased the shelf-life of chicken kabab. Irradiation did not influence the major constituents of chicken kabab (moisture, protein and fats). No significant differences (p>0.05) were observed for total acidity between non-irradiated (control) and irradiated chicken kabab. Thiobarbitric acid (TBA) values (expressed as mg malonaldehyde (MDA)/kg chicken kabab) and volatile basic nitrogen (VBN) in chicken kabab were not affected by the irradiation. Sensory evaluation showed no significant differences between irradiated and non-irradiated samples.     

IFSS, TG, FT-IR spectra of impregnated sugar palm (Arenga pinnata) fibres and mechanical properties of their composites

This study aimed to investigate the effect of resin impregnation on the interfacial shear strength (IFSS), thermogravimetric (TG) and fourier transform infrared (FT-IR) of sugar palm (Arenga pinnata) fibres. In addition, the effect of resin impregnation on the mechanical properties of sugar palm fibre reinforced unsaturated polyester (UP) composites was also studied. The fibres were impregnated with UP via vacuum resin impregnation process at a pressure of 600 mmHg for 5 min. Composites of 10, 20, 30, 40 and 50 % fibre loadings were fabricated and tested for tensile and flexural properties. It was observed that the impregnation process caused the fibres to be enclosed by UP resin and this gave a strong influence to the increase of its interfacial bonding by the increase of its IFSS from single fibre pull-out test. It was also observed with TG and FT-IR spectra that the impregnated fibre had lower moisture uptake than the control and there was no significant increase in thermal stability of the impregnated fibre. The sequence of fibre decomposition started from the evaporation of moisture, hemicelluloses, cellulose, lignin and finally ash content and the presence of these components were proven by FT-IR spectra. For the composite specimens, due to the high interfacial bonding of the impregnated fibre and the matrix, the impregnated composites showed consistently higher tensile strength, tensile modulus, elongation at break, flexural strength, flexural modulus and toughness than the control samples. It was also observed that 30 % fibre loading gave optimum properties.     

Liquid‐Liquid Microextraction Coupled with High Performance Liquid Chromatography for Determination of Platinum

Liquid‐liquid microextraction (LLME) coupled with high performance liquid chromatography (HPLC) for the analysis of platinum is described. The analyte were extracted from 10.0 mL aqueous sample into organic phase. The extraction time was 20 min. Factors such as pH in aqueous phase, extraction times, and stirring rate were optimised. The method was applied for determination of platinum in mixture samples. The linearity range was from 1.0 to 100 nM and the detection limits was 0.1 nM. Relative standard deviations (%, n = 5) was 0.44 to 0.81. All experiments were carried out at room temperature, 35 ± 0.2°C.     

Effects of gamma irradiation on chemical,microbial quality and shelf life of shrimp

In the present study the combined effect of gamma irradiation (1, 3 and 5 kGy) and storage at two temperatures: refrigeration (+4 °C) and frozen (?18 °C), on the shelf-life extension of fresh shrimp meat was investigated. The study was based on microbiological and physicochemical changes occuring in the shrimp samples. Total volatile base nitrogen values and trimethylamine values for irradiated shrimp samples were significantly lower than non-irradiated samples at both storage temperatures, and the rate of decrease was more pronounced in samples irradiated at the higher dose (p<0.05). Thiobarbituric acid values for irradiated shrimp samples were significantly higher than non-irradiated samples at both storage temperatures (p<0.05). pH values of shrimp samples were affected significantly by both irradiating dose and storage temperatures (p<0.05). Microbial counts for non-irradiated shrimp samples were higher than the respective irradiated samples at both storage temperatures (p<0.05). The results revealed that irradiation at high dose (5 kGy) might enhance lipid oxidation, although the growth of microorganisms and protein oxidation was inhibited.     

Effect of gamma-irradiation and refrigerated storage on the improvement of quality and shelf life of pear (Pyrus communis L., Cv. Bartlett/William)

Gamma-irradiation alone and in combination with refrigeration was tested consecutively for 3 years for extending the shelf life of pear. Matured green pears were irradiated in the dose range of 0.8–2.0 kGy and stored under ambient (temperature 25±2 °C, RH 70%) and refrigerated (temperature 3±1 °C, RH 80%) conditions. Dose range of 1.5–1.7 kGy extended the storage life of pear by 14 days under ambient conditions. Control unirradiated pears were almost fully ripe within 8 days, while as the pears irradiated in the dose range of 1.5–1.7 kGy were fully ripe within 22 days of ambient storage. Irradiation dose of 1.5–1.7 kGy significantly inhibited the decaying of pears upto 16 days of ambient storage. Irradiation in combination with refrigeration prevented the decaying of pears upto 45 days as against the 35% decay in unirradiated samples. Irradiation dose of 1.5–1.7 kGy also gave an extension of 8 and 4 days during additional ambient storage of the pears following 30 and 45 days of refrigeration, respectively.     

Isomeric yield ratios in the photoproduction of 52m,gMn from natural iron using 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung

The isomeric yield ratios for the ^natFe(γ,xn1p)^52m,gMn reactions have been measured by the activation and the γ-ray spectroscopic methods at 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung energies. The high purity natural iron foils in disc shape were irradiated with uncollimated bremsstrahlung beams of the Pohang Accelerator Laboratory. The induced activities in the irradiated foils were measured by the high-resolution γ-ray spectrometry with a calibrated high-purity Germanium (HPGe) detector. In order to improve the accuracy of the experimental results the necessary corrections were made in the gamma activity measurements and data analysis. The obtained isomeric yield ratios for the ^natFe(γ,xn1p)^52m,gMn reactions at 50-, 60-, 70-MeV, and 2.5-GeV bremsstrahlung energies are 0.27 ± 0.03, 0.33 ± 0.04, 0.34 ± 0.04, and 1.25 ± 0.15, respectively. The present results at 50-, 60-MeV, and 2.5-GeV bremsstrahlung energies are the first measurements. We found that the isomeric yield ratio of the ^natFe(γ,xn1p)^52m,gMn reaction depends on the incident bremsstrahlung energy and the mass difference between the product and the target nucleus when we compared the present results with other experimental data at different energies.     

Electrochemical determination of prolintane in pharmaceutical formulations and in human urine

The oxidative behavior of 1-[1-(phenylmethyl)butyl]pyrrolidine, prolintane, was studied at a glassy carbon electrode using linear-sweep and differential-pulse voltammetry. The oxidation process was shown to be irreversible using 0.04 M Britton–Robinson buffer and was diffusion-adsorption controlled. Two voltammetric methods were developed for the determination of prolintane using different techniques: linear-sweep and differential-pulse voltammetry. The peak current varied linearly with prolintane concentrations in the range of 1.0 × 10⁻⁵ −2.5 × 10⁻⁴ M, with a detection limit of 8.5 × 10⁻⁶ and 4.0 × 10⁻⁶ M, and with relative standard deviations of 2.1 % and 3.1 %, respectively. The methods were applied to commercial preparations, giving relative errors less than 3.1 % and relative standard deviations lower than 4.8 % (n = 10). Determination of prolintane (down to the 8.5 × 10⁻⁸ M level) can be performed by using a preconcentration step prior to the determination by differential-pulse voltammetry in 0.04 M Britton–Robinson buffer (pH 8.0) with preconcentration potential of 0.0 V. The detection limit was found to be 6.2 × 10⁻⁸ M (4 min preconcentration) and the relative standard deviation for 2.5 × 10⁻⁷ M prolintane (n = 5) was 4.6 %. Applicability to human urine analysis is illustrated (recovery 98 ± 2 %). Standard additions method can be used to determine prolintane in real samples of urine.     

LC Determination of Ketorolac in Human Plasma and Urine for Application to Pharmacokinetic Studies

A simple, specific and sensitive liquid chromatographic method has been developed for the assay of ketorolac in human plasma and urine. The clean-up of plasma and urine samples were carried out by protein precipitation procedure and liquid–liquid extraction, respectively. Separation was performed by a Waters sunfire C₁₈ reversed-phase column maintained at 35 °C. The mobile phase was a mixture of 0.02 M phosphate buffer (pH adjusted to 4.5 for plasma samples and to 3.5 for urine samples) and acetonitrile (70:30, v/v) at a flow rate of 1.0 mL min⁻¹. The UV detector was set at 315 nm. Nevirapine was used as an internal standard in the assay of urine sample. The method was validated over the concentration range of 0.05–8 and 0.1–10 μg mL⁻¹ for ketorolac in human plasma and urine, respectively. The limits of detection were 0.02 and 0.04 μg mL⁻¹ for plasma and urine estimation at a signal-to-noise ratio of 3. The limits of quantification were 0.05 and 0.1 μg mL⁻¹ for plasma and urine, respectively. The extraction recoveries were found to be 99.3 ± 4.2 and 80.3 ± 3.7% for plasma and urine, respectively. The intra-day and inter-day standard deviations were less than 0.5. The method indicated good performance in terms of specificity, linearity, detection and quantification limits, precision and accuracy. This assay demonstrated to be applicable for clinical pharmacokinetic studies.

     

LC Determination of Ketorolac in Human Plasma and Urine for Application to Pharmacokinetic Studies

A simple, specific and sensitive liquid chromatographic method has been developed for the assay of ketorolac in human plasma and urine. The clean-up of plasma and urine samples were carried out by protein precipitation procedure and liquid–liquid extraction, respectively. Separation was performed by a Waters sunfire C₁₈ reversed-phase column maintained at 35 °C. The mobile phase was a mixture of 0.02 M phosphate buffer (pH adjusted to 4.5 for plasma samples and to 3.5 for urine samples) and acetonitrile (70:30, v/v) at a flow rate of 1.0 mL min^?1. The UV detector was set at 315 nm. Nevirapine was used as an internal standard in the assay of urine sample. The method was validated over the concentration range of 0.05–8 and 0.1–10 μg mL^?1 for ketorolac in human plasma and urine, respectively. The limits of detection were 0.02 and 0.04 μg mL^?1 for plasma and urine estimation at a signal-to-noise ratio of 3. The limits of quantification were 0.05 and 0.1 μg mL^?1 for plasma and urine, respectively. The extraction recoveries were found to be 99.3 ± 4.2 and 80.3 ± 3.7% for plasma and urine, respectively. The intra-day and inter-day standard deviations were less than 0.5. The method indicated good performance in terms of specificity, linearity, detection and quantification limits, precision and accuracy. This assay demonstrated to be applicable for clinical pharmacokinetic studies.