bluuebunny/crossref_metadata_2025 huggingface dataset:
Detection of Genetically Modified Crops and Their Derivatives: Critical Steps in Sample Preparation and Extraction
Authors: Terry Catherine F , Harris Neil , Parkes Helen C
Published: February 2020

The detection of genetically modified crops in foodstuff relies on detection of transgenic DNA or protein material in the sample matrix. Purified DNA or proteins are used as analytical material for polymerase chain reaction technologies and immunodiagnostics. Successful sample preparation is critical to the validity of subsequent analysis. For routine analysis, a good sample preparation technique should be simple, safe, and inexpensive while reproducibly generating DNA/protein of sufficient quality and yield. The suitability of isolated DNA or protein as an analyte for a detection or characterization technique depends on amount or concentration, purity, and integrity, each of which may be influenced by sample matrix and the extraction technique, and, in turn, may impact the validity of analytical techniques. The key sample preparation steps of homogenization, pretreatment, extraction, and purification are discussed as well as typical analytical methods. Consideration is given to application of these steps for particular sample matrixes to maximize yield, reduce inhibition effects, and minimize contamination. The choice of the most appropriate and valid methods for sample preparation from particular foods is discussed with respect to DNA analysis. Attention is also given to ease of use, cost, and generic applicability of the procedures.
Characterization of Copolymer Hydroxybutyrate/Hydroxyvalerate from Saponified Vernonia, Soybean, and “Spent” Frying Oils
Authors: Saeed Kamal A , Eribo Broderick E , Ayorinde Folahan O , Collier Ledelle
Published: February 2020

Poly(β-hydroxyalkanoate)s (PHAs) were biosynthesized by Ralstonia eutropha (formerly known as Alcaligenes eutrophus) by using saponified soybean, vernonia, and “spent” frying oils. These PHAs were isolated and characterized by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (MALDI–TOFMS), gas chromatography/mass spectrometry (GC/MS), proton nuclear magnetic resonance spectrometry (1H NMR), and 2-dimensional homonuclear (1H–1H) correlation spectroscopy (COSY). The analytical results revealed that the PHAs produced from saponified vernonia and soybean oils were copolymers of hydroxybutyrate (HB) and hydroxyvalerate (HV), that is, P(HB/HV)s, whereas the saponified “spent” frying oil produced only poly(β- hydroxybutyrate) (PHB) homopolymer. MALDI–MS, GC/MS, and NMR independently confirmed the composition of the PHAs. Saponified soybean oil and vernonia oil PHAs contained approximately 4 and 1% HV units, respectively. For comparison, commercial PHB and P(HB/HV), produced by R. eutropha by using glucose and a cosubstrate of glucose and propionic acid, respectively, as carbon sources, were similarly characterized.
Real-Time Detection of Genetically Modified Soya Using Lightcycler and ABI 7700 Platforms with TaqMan, Scorpion, and SYBR Green I Chemistries
Authors: Terry Catherine F , Shanahan Della J , Ballam Lydia D , Harris Neil , McDowell David G , Parkes Helen C
Published: February 2020

A comparative cross platform evaluation of real-time polymerase chain reaction detection of DNA sequences present in Roundup Ready soya was undertaken using the ABI 7700 and Roche Lightcycler detection systems in combination with 3 different detection chemistries: TaqMan, Scorpion primers, and SYBR Green I fluorescent dye. Various copy numbers of a plasmid containing the soya lectin sequence were used to determine the sensitivity and reproducibility of the different technology combinations and to examine both inter and intra machine variability. To examine the relative accuracy of each technology, the genetically modified soya content of baked products containing known amounts of Roundup Ready soya was determined by detection of lectin and the EPSPS transgene. It was determined that the combination of TaqMan detection chemistry and the ABI 7700 platform represented the best method for quantitative detection of genetically modified organisms in terms of both precision and accuracy.
Molecular Methods for Identification and Detection of Bacterial Food Pathogens
Authors: Rijpens Nancy P , Herman Lieve M F
Published: February 2020

The polymerase chain reaction (PCR) shortens conventional microbiological methods for the detection of food pathogens either by replacing the conventional biochemical and serological identification or by its direct use on pre-enrichment media or food products. PCR allows fast and highly reliable identification of bacterial taxa, particularly phenotypically atypical bacterial strains. For reliablity, PCR primers and reaction conditions must be thoroughly optimized and evaluated, appropriate sample preparations must be developed, and a stringent laboratory protocol must be followed. Positive control systems are used to monitor possible inhibition of the reaction and negative controls are needed to monitor for contamination. The most recent developments involve messenger RNA-based (mRNA-based) detection of viable bacterial pathogens and real-time PCR quantitation of pathogens.
Determination of Low-Level Residual Ethylene Oxide by Using Solid-Phase Microextraction and Gas Chromatography
Authors: Ayoub Kamal , Harris Leonard , Thompson Bill
Published: February 2020

Current methods of analysis for ethylene oxide (EO) in medical devices include headspace and simulated-use extractions followed by gas chromatography with either a packed or a capillary column. The quantitation limits are about 0.5–1.0 μg/g for a packed column and about 0.1–0.2 μg/g for a capillary column. The current allowable levels of EO on medical devices sterilized with EO gas as outlined in International Organization for Standardization (ISO) 10993-7 may be significantly reduced from current levels by applying the ISO Draft International Standard 10993-17 method for establishing allowable limits. This may require EO test methods with detection and quantitation limits that are much lower than those of the currently available methods. This paper describes a new method that was developed for the determination of low-level EO by solid-phase microextraction using the direct-immersion method. Factors such as temperature and stirring were found to affect absorption efficiency and absorption time. A low extraction temperature (about 6°C) was found to be more efficient than room-temperature extraction. Stirring was found to reduce absorption time by about 50%. Under these conditions, detection and quantitation limits of 0.002 and 0.009 μg/g, respectively, were obtained by using a capillary column. As a result, this method makes compliance with lower EO limits feasible.
Determination of Hydroxyurea in Capsules and Biological Fluids by Ion-Selective Potentiometry and Fluorimetry
Authors: El-Kosasy Amira M
Published: February 2020

Two hydroxyurea selective electrodes were investigated with β-cyclodextrin used as ionophore and either tetrakis (p-chlorophenyl) borate (electrode 1), or tetrakis [3,4-bis (trifluoromethyl) phenyl] borate (electrode 2), as a fixed anionic site in a polymeric matrix of carboxylated polyvinyl chloride. Linear responses of hydroxyurea within a concentration range of 10−5–10−3M with slopes of 51.2 and 58.6 mV/decade with pH 3–6 were obtained by using electrodes 1 and 2, respectively. Two spectrofluorimetric methods involving the formation of drug–Al(III) complex (method 3) and drug–Mg(II) complex (method 4) at pH 5 were also investigated. These complexes emit fluorescence at wavelengths of 380 and 355 nm, after excitation at 305 nm, for Al and Mg complexes, respectively. The calibration graphs were rectilinear from 0.5 to 2.5 μg/mL for the Al complex and 1 to 5 μg/mL for the Mg complex. The 4 proposed methods display useful analytical characteristics for determination of hydroxyurea, with average recoveries of 100.2 ± 0.83 and 99.4 ± 1.81% in capsules and 99.7 ± 0.70 and 99.4 ± 1.25% in biological fluids for the potentiometric and fluorimetric methods, respectively. Results obtained by the proposed procedures were statistically analyzed and compared with those obtained by the U.S. Pharmacopeial method. The 4 proposed procedures were also used to determine the stability of the drug in the presence of its degradate, hydroxylamine.
Determination of Acesulfame and Sucralose in Oral Electrolyte Maintenance Solution by Liquid Chromatography
Authors: Johns Paul , Dowlati Lobat
Published: February 2020

A method was developed for the direct, simultaneous determination of acesulfame and sucralose in oral electrolyte maintenance solution (OEMS). Analyte separation and quantitation were achieved by gradient reversed-phase liquid chromatography (LC) and UV absorbance at 192 nm, respectively. Detection at a second wavelength, 214 nm, was used to check sucralose peak purity; 20 μL OEMS was injected without preparation or dilution. System linearity was demonstrated as 192 nm peak area versus analyte concentration at 80–120% OEMS sweetener fortification (r > 0.999, and all residuals <0.5%, for both acesulfame and sucralose). Spike recoveries for OEMS samples prepared at 3 spiking levels (80, 100, and 120% sweetener fortification) ranged from 100.3 to 102.0% for acesulfame, and from 97.9 to 102.3% for sucralose. In a second assessment of method accuracy, the same spiked OEMS samples were tested by 2 alternative methods: acesulfame (LC/UV at 230 nm) and sucralose (anion exchange–pulsed amperometric detection). Results for the alternative acesulfame method were within 1.2%, and for the alternative sucralose method within 6.0%, of the corresponding results obtained by the 192 nm method. Repeatability and intermediate precision RSD values were <1% for acesulfame and <3% for sucralose. The limits of quantitation were 1.6 and 32 mg/L for acesulfame potassium and sucralose, respectively. Despite the weak UV absorptivity of sucralose and the consequent small size of its LC peak, no evidence was found for sucralose interference in any of the commercial OEMS flavors.
Comparison of Micellar Electrokinetic Chromatography, Liquid Chromatography, and Microbiologic Assay for Analysis of Cephalexin in Oral Suspensions
Authors: Steppe Martin , Aurora Prado María S , Tavares Marina F M , Pinto Teresinha J A , Kedor-Hackmann Erika R M , Santoro Maria Inês R M
Published: February 2020

Two well-accepted methodologies, based on a microbiologic assay (MA) and liquid chromatography (LC), and a novel methodology using micellar electrokinetic chromatography (MEKC), were compared for the determination of cephalexin in commercially available and simulated samples of oral suspensions. The MA, described in the BrazilianPharmacopeia, was performed with a strain of Staphylococcus aureus ATCC 6538 as the test organism, following the cylinder-plate method. The LC analysis followed the European Pharmacopoeia, 3rd Ed., and was used with minor modifications. The MEKC analysis was based on a previous work of the group. Estimates of the repeatability relative standard deviations of the MA, LC, and MEKC methods in the analysis of a commercial sample were 0.34, 0.42, and 0.37%, respectively. The recovery obtained with LC was 99.90 ± 1.11%; for MEKC, it was 100.09 ± 0.56%. Although the 3 methodologies were statistically equivalent for the determination of cephalexin in oral suspensions, MA gave suitable repeatability despite being nonspecific and time-consuming. MEKC provided faster analysis and higher column efficiency, whereas LC presented superior sensitivity. The results indicated that MEKC can be used as an alternative method to MA and LC in routine quality control laboratories.
Determination of Sample Size for Validation of Allergen-Screening Methods
Authors: McClure Foster D , Graves Qian F
Published: February 2020

For various levels of confidence (i.e., 80 and 90%) and ratios (K = σP2/σN2 where σP2 and σN2 are the analyte variances for the positive and negative distributions, respectively), sample sizes sufficient to test the requirements that a given method detects ≥90% of the positives (≥5 ppm of a given analyte) while misclassifying ≤10% of the negatives (implying a specificity rate, true negatives that will be correctly classified, of 90%) were estimated by using a rationale that minimizes the cost of sampling.
Measurement Uncertainty in Microbiology
Authors: Forster Lynne I
Published: February 2020

Testing laboratories wishing to comply with the requirements of ISO/IEC 17025:1999 need to estimate uncertainty of measurement for their quantitative methods. Many microbiological laboratories have had procedures available for monitoring variability in duplicate results generated by laboratory analysts for some time. These procedures, however, do not necessarily include all possible contributions to uncertainty in the calculations. Procedures for estimating microbiological method uncertainty, based on the Poisson distribution, have been published but, at times, the procedures can either underestimate uncertainty or require laboratories to undertake considerable experimental studies and more complex statistical calculations. This paper proposes procedures for estimating uncertainty of measurement in microbiology, whereby routine laboratory quality control data can be analyzed with simple statistical equations. The approaches used in these procedures are also applied to published data and examples, demonstrating that essentially equivalent results can be obtained with these procedures.
Determination of Atropine (Hyoscyamine) Sulfate in Commercial Products by Liquid Chromatography with UV Absorbance and Fluorescence Detection: Multilaboratory Study
Authors: Cieri Ugo R ,   Collaborators:, Bertrand R , Choi K K , Gagnon J , Krol P , Latzo P , Lau D , Melendez J , Pyramides G , Sen S , Steible D , Weigand J
Published: February 2020

A liquid chromatographic (LC) method with 2 detection systems for determining atropine (hyoscyamine) sulfate in commercial products was tested in a multilaboratory study. Depending on the type of product, sample solutions are prepared in methanol or methanol–water (1 + 1). The standard solution contains about 1.0 mg atropine sul-fate/100 mL and is prepared in the same solvent used in sample preparation. LC separations are performed on a 7.5 cm Novapak silica column. The mobile phase is prepared by mixing 970 mL methanol with 30 mL of a 1% aqueous solution of 1-pentanesulfonic acid, sodium salt. Detection is by 2 systems, UV absorbance detection at 220 nm and fluorescence detection with excitation at 255 nm and emission at 285 nm. The injection volume is 100 or 200 μL. The following materials were used for the study: 2 separate samples of tablets labeled to contain 0.4 mg atropine sulfate, 2 separate samples of extended-release tablets labeled to contain 0.375 mg hyoscyamine sulfate, one sample of atropine sulfate injection labeled to contain 2 mg/mL, and one sample of 1% (v/v) atropine sul-fate ophthalmic. Eight participants analyzed 2 separate portions of the 6 samples by both detection systems. A ninth participant analyzed the samples in duplicate but only by UV absorbance detection because of the unavailability of a fluorescence detector. The relative standard deviation (RSD) between laboratories ranged from 1.4 to 3.3% for samples of tablets and injections but higher for ophthalmic solutions (5.1–5.2%). A linearity study was conducted in the originating laboratory before the multilaboratory study with 5 solutions ranging in concentration from 0.80 to 1.20 mg atropine sul-fate in 100 mL. Average recoveries were 100.0% by UV absorbance detection and 99.9% by fluorescence detection; the RSDs were 1.1 and 1.2%, respectively.
Methods of Analysis for Anthocyanins in Plants and Biological Fluids
Authors: Mazza G , Cacace Juan E , Kay Colin D
Published: February 2020

Anthocyanins are the largest group of water-soluble pigments in the plant kingdom. They are responsible for most of the red, blue, and purple colors of fruits, vegetables, flowers, and other plant tissues or products. The analysis of anthocyanins is complex as a result of their ability to undergo structural transformations and complexation reactions. In addition, they are difficult to measure independently of other flavonoids, as they have similar structural and reactivity characteristics. Anthocyanins are generally extracted with weakly acidified alcohol-based solvents, followed by concentration (under vacuum), and purification of the pigments. Paper and/or thin-layer chromatography and UV-Vis spectroscopy have traditionally been used for the identification of anthocyanins. Capillary zone electrophoresis, a hybrid of chromatography and electrophoresis, is gaining popularity for the analysis of anthocyanins; however, liquid chromatography (LC) has become the standard method for identification and separation in most laboratories and may be used for both preparative and quantitative analysis. LC with mass spectrometry (MS) and nuclear magnetic resonance (NMR) spectroscopy are possibly the most powerful methods for the structural elucidation of anthocyanins available, to date. At present, the most satisfactory method for mixture analysis is the multistep method of separation, isolation, and quantification by LC with peak identification by MS and high-field NMR.
Differential Electrolytic Potentiometric Determination of Some Amino Acids in Dosage Forms
Authors: Al-Ghannam Sheikha M , Abulkibash Abdalla M S , Al-Olyyan Abeer M
Published: February 2020

The application of direct-current differential electrolytic potentiometry to the nonaqueous titration of amino acids was investigated. The basic character of amino acids in acetic acid was enhanced to permit their direct titration with perchloric acid. A pair of antimony electrodes was used as an indicating system. The shapes of the titration curves obtained were almost symmetrical with sharp peaks. The optimum current density for those titrations was found to be 1–2 μA/cm2. The procedure was applied successfully to the determination of certain amino acids in drug formulations, and the results were favorably compared statistically with those obtained by official methods.
Development and Validation of a Gas Chromatography/Mass Spectrometry Procedure for Confirmation of Para-Toluenesulfonamide in Edible Fish Fillet Tissue
Authors: Idowu Olutosin R , Kijak Philip J , Meinertz Jeffery R , Schmidt Larry J
Published: February 2020

Chloramine-T is a disinfectant being developed as a treatment for bacterial gill disease in cultured fish. As part of the drug approval process, a method is required for the confirmation of chloramine-T residues in edible fish tissue. The marker residue that will be used to determine the depletion of chloramine-T residues from the edible tissue of treated fish is para-toluenesulfonamide (p-TSA), a metabolite of chloramine-T. The development and validation of a procedure for the confirmation of p-TSA is described. Homogenized fish tissue is dried by mixing with anhydrous sodium sulfate, and the mixture is extracted with methylene chloride. The extract is passed through a silica gel solid-phase extraction column, from which p-TSA is subsequently eluted with acetonitrile. The acetonitrile extract is evaporated, and the oily residue is dissolved in hexane. The hexane solution is shaken with fresh acetonitrile. The acetonitrile solution is evaporated and the residue is redissolved in dilute potassium hydroxide solution. The aqueous solution is extracted with methylene chloride to further remove more of the fat co-extractive. The aqueous solution is reacted with pentafluorobenzyl bromide in presence of tetrabutylammonium hydrogensulfate. The resulting di-(pentafluorobenzyl) derivative of p-TSA is analyzed by gas chromatography/mass spectrometry. This method permits the confirmation of p-TSA in edible fish tissue at 20 ppb.
Studies on the Stability of Acrylamide in Food During Storage
Authors: Hoenicke Katrin , Gatermann Robert
Published: February 2020

Acrylamide levels in a variety of food samples were analyzed before and after 3 months of storage at 10°–12°C. The analysis was performed by liquid chromatography tandem mass spectrometry (LC/MS/MS) using deuterium-labeled acrylamide as internal standard. Acrylamide was stable in most matrixes (cookies, cornflakes, crispbread, raw sugar, potato crisps, peanuts) over time. However, slight decreases were determined for dietary biscuits (83–89%) and for licorice confection (82%). For coffee and cacao powder, a significant decrease occurred during storage for 3 or 6 months, respectively. Acrylamide concentrations dropped from 305 to 210 μg/kg in coffee and from 265 to 180 μg/kg in cacao powder. On the contrary, acrylamide remained stable in soluble coffee as well as in coffee substitutes. Reactions of acrylamide with SH group-containing substances were assumed as the cause for acrylamide degradation in coffee and cacao. Spiking experiments with acrylamide revealed that acrylamide concentrations remained stable in baby food, cola, and beer; however, recovery levels dropped in milk powder (71%), sulfurized apricot (53%), and cacao powder (17%). These observations suggest that variations in the acrylamide content of food, especially in coffee and cacao, can vary depending on the storage time because special food constituents and/or reaction products can affect the levels.
Development and Validation of Spectrophotometric Methods for Determination of Fluoxetine, Sertraline, and Paroxetine in Pharmaceutical Dosage Forms
Authors: Darwish Ibrahim A
Published: February 2020

Three simple and sensitive spectrophotometric methods were developed and validated for determination of the hydrochloride salts of fluoxetine, sertraline, and paroxetine in their pharmaceutical dosage forms. These methods were based on the reaction of the N-alkylvinylamine formed from the interaction of the free secondary amino group in the investigated drugs and acetaldehyde with each of 3 haloquinones, i.e., chloranil, bromanil, and 2,3-dichloronaphthoquinone, to give colored vinylamino-substituted quinones. The colored products obtained with chloranil, bromanil, and 2,3-dichloronaphthoquinone exhibit absorption maxima at 665, 655, and 580 nm, respectively. The factors affecting the reactions were studied and optimized. Under the optimum reaction conditions, linear relationships with good correlation coefficients (0.9986–0.9999) were found between the absorbances and the concentrations of the investigated drugs in the range of 4–120 μg/mL. The limits of detection for the assays ranged from 1.19 to 2.98 μg/mL. The precision values of the methods were satisfactory; the relative standard deviations were 0.56–1.24%. The proposed methods were successfully applied to the determination of the 3 drugs in pure and pharmaceutical dosage forms with good accuracy; the recoveries ranged from 99.1 to 101.3% with standard deviations of 1.15–1.92%. The results compared favorably with those of reported methods.
Precise Method for the Measurement of Catalase Activity in Honey
Authors: Huidobro José F , Sánchez M Pilar , Muniategui Soledad , Sancho M Teresa
Published: February 2020

An improved method is reported for the determination of catalase activity in honey. We tested different dialysis membranes, dialysis fluid compositions and amounts, dialysis temperatures, sample amounts, and dialysis times. The best results were obtained by dialysis of 7.50 g sample in a cellulose dialysis sack, using two 3 L portions of 0.015M sodium phosphate buffer (pH 7.0) as the dialysis fluid at 4°C for 22 h. As in previous methods, catalase activity was determined on the basis of the rate of disappearance of the substrate, H2O2, with the H2O2 determined spectrophotometrically at 400 nm in an assay system containing o-dianisidine and peroxidase. Trials indicated that the best solvent for the o-dianisidine was 0.2M sodium phosphate buffer, pH 6.1; the best starting H2O2 concentration was 3mM; the best HCl concentration for stopping the reaction was 6N; and the best sample volume for catalase measurement was 7.0 mL. Precision values (relative standard deviations for analyses of 10 subsamples of each of 3 samples) were high, ranging from 0.48% for samples with high catalase activity to 1.98% for samples with low catalase activity.
In vivo Determination of Amino Acid Bioavailability in Humans and Model Animals
Authors: Fuller Malcolm F , Tomé Daniel
Published: February 2020

Because the digestion of many dietary proteins is incomplete, and because there is a continuous (but variable) entry into the intestinal lumen of endogenous protein and amino acid nitrogen that is also subject to digestion, the fluxes of nitrogen, amino acids, and protein in the gut exhibit a rather complicated pattern. Methods to distinguish and quantitate the endogenous and dietary components of nitrogen and amino acids in ileal chyme or feces include the use of a protein-free diet, the enzyme-hydrolyzed protein method, different levels of protein intake, multiple regression methods, and stable-isotope labelling of endogenous or exogenous amino acids. Assessment of bioavailability can be made, with varying degrees of difficulty, in man directly but, for routine evaluation of foods, the use of model animals is attractive for several reasons, the main ones being cost and time. Various animals and birds have been proposed as models for man but, in determining their suitability as a model, their physiological, enzymological, and microbiological differences must be considered. Fecal or ileal digestibility measurements, as well as apparent and true nitrogen and amino acid digestibility measurements, have very different nutritional significance and can, thus, be used for different objectives. Measurements at the ileal level are critical for determining amino acid losses of both dietary and endogenous origin, whereas measurements at the fecal level are critical in assessing whole-body nitrogen losses. A complementary and still unresolved aspect is to take into account the recycling of intestinal nitrogen and bacterial amino acids to the body.
In vitro Determination of the Release Kinetics of Peptides and Free Amino Acids During the Digestion of Food Proteins
Authors: Savoie Laurent , Agudelo Rafael A , Gauthier Sylvie F , Marin Johanne , Pouliot Yves
Published: February 2020

The kinetics of peptide release during in vitro digestion of 4 protein sources (casein, cod protein, soy protein, and gluten) were investigated. Samples were sequentially hydrolyzed with pepsin (30 min) and pancreatin (2, 4, or 6 h) in a dialysis cell with continuous removal of digestion products. Nondialyzed digests were fractionated by ion-exchange chromatography and ultrafiltration. Animal proteins were digested at a greater rate than plant proteins. Target amino acids of specific enzymes appeared more rapidly in the dialyzed fractions when compared to other amino acids. Throughout the hydrolysis, nondialyzed digests contained a higher proportion of peptide mixtures with basic-neutral properties. Except for gluten, peptide fractions with molecular weights that exceeded 10 kDa (basic-neutral, BN > 10) were rapidly hydrolyzed during the first 2 h of pancreatin digestion. The kinetics of release and the composition of peptide fractions were different when the protein sources were compared. The analysis of amino acids revealed that threonine and proline proportions were relatively high in BN > 10 and in peptide fractions with molecular weight between 10-1 kDa (BN 10-1), while tyrosine, phenylalanine, lysine, and arginine predominated in the low molecular weight (<1 kDa) fractions. More resistant peptides were generally rich in proline and glutamic acid. The role of in vitro digestion assays in dietary protein quality evaluation is discussed.
Effects of Antinutritional Factors on Protein Digestibility and Amino Acid Availability in Foods
Authors: Gilani G Sarwar , Cockell Kevin A , Sepehr Estatira
Published: February 2020

Digestibility of protein in traditional diets from developing countries such as India, Guatemala, and Brazil is considerably lower compared to that of protein in typical North American diets (54–78 versus 88–94%). The presence of less digestible protein fractions, high levels of insoluble fiber, and high concentrations of antinutritional factors in the diets of developing countries, which are based on less refined cereals and grain legumes as major sources of protein, are responsible for poor digestibility of protein. The effects of the presence of some of the important antinutritional factors on protein and amino digestibilities of food and feed products are reviewed in this chapter. Food and feed products may contain a number of antinutritional factors that may adversely affect protein digestibility and amino acid availability. Antinutritional factors may occur naturally, such as glucosinolates in mustard and rapeseed protein products, trypsin inhibitors and hemagglutinins in legumes, tannins in legumes and cereals, phytates in cereals and oilseeds, and gossypol in cottonseed protein products. Antinutritional factors may also be formed during heat/alkaline processing of protein products, yielding Maillard compounds, oxidized forms of sulfur amino acids, D-amino acids, and lysinoalanine (LAL, an unnatural amino acid derivative). The presence of high levels of dietary trypsin inhibitors from soybeans, kidney beans, or other grain legumes can cause substantial reductions in protein and amino acid digestibilities (up to 50%) in rats and pigs. Similarly, the presence of high levels of tannins in cereals, such as sorghum, and grain legumes, such as fababean (Vicia faba L.), can result in significantly reduced protein and amino acid digestibilities (up to 23%) in rats, poultry, and pigs. Studies involving phytase supplementation of production rations for swine or poultry have provided indirect evidence that normally encountered levels of phytates in cereals and legumes can reduce protein and amino acid digestibilities by up to 10%. D-amino acids and LAL formed during alkaline/heat treatment of proteins such as casein, lactalbumin, soy protein isolate, or wheat proteins are poorly digestible (less than 40%), and their presence can reduce protein digestibility by up to 28% in rats and pigs. A comparison of the protein digestibility determination in young (5-week) versus old (20-month) rats suggests greater susceptibility to the adverse effects of antinutritional factors in old rats than in young rats. Therefore, the inclusion of protein digestibility data obtained with young rats, as the recommended animal model, in the calculation of PDCAAS (Protein Digestibility-Corrected Amino Acid Score) may overestimate protein digestibility and quality of products, especially those containing antinutritional factors, for the elderly. For products specifically intended for the elderly, protein digestibility should be determined using more mature rats.
A Flow-Injection Biamperometric Method for Determination of Pantoprazole in Pharmaceutical Tablets
Authors: Castro Suzana L , Neto Osmundo D Pessoa , Santos Sergio R B , Medeiros Everaldo P , Lima Ricardo A C , Martins Valdomiro L , Araúo Mario C U , Santos Josué C C , Korn Mauro
Published: February 2020

A flow-injection biamperometric method for determination of pantoprazole (PTZ) in pharmaceutical tablets is reported for the first time. The reversible redox couples Fe3+/Fe2+, Fe(CN)63−/Fe(CN)64−, Ce4+/Ce3+, VO3−/VO2+, and I2/I− were tested as indicating redox systems for biamperometric determination of PTZ in a flow-injection assembly with optimized flow parameters. The best results were obtained using VO3−/VO2+, which showed to be a selective and sensitive biamperometric indicating system for PTZ even in the presence of excipients and antioxidants that typically are found in drugs. The analytical graph was linear (r = 0.99945) in the range from 10 to 100 mg/L using 25 mmol/L VO3− as the reagent and water as the carrier stream and applying 100 mV between the 2 platinum wire electrodes. The limits of detection and quantitation were 200 and 667 μg/L, respectively, with a sensibility of calibration of 22.6 mV/mg/L. The proposed method was successfully applied to determine PTZ in commercial pharmaceutical tablets with a mean relative error of 1.60% (n = 5) and mean relative standard deviation of 3.10%. Recoveries close to 100% showed good agreement between the expected amount of PTZ in tablets (40 mg) and the results found by the application of the proposed method and demonstrated that the formulations used in the tablet compositions do not interfere in the PTZ analysis. The system had good stability, with a relative standard deviation of 3.80% for 9 sequential injections of a 60 mg/L PTZ solution. A sampling rate of about 100 samples/h was obtained.
Rapid Evaluation of Surface Sanitation by Electrical Measurement
Authors: Álvarez Fernando , Sanz Susana , Rodríguez-Jerez José Juan
Published: February 2020

Electrical measurements are easier and faster than traditional methods for evaluating surface sanitation in the food industry. However, the behavior of sublethally damaged bacteria is different in each method. The electrical method is more sensitive to the presence of disinfectant traces in the samples. These issues lead to low correlations between both methods (r2 < 0.7). The use of smaller sample volumes in electrical measurements, together with the addition of a blend of neutralizers to the sample and the subsequent removal by filtration, provide r2 values >0.9. The developed protocol shows an excellent correlation with traditional methods and facilitates the adaptation of the electrical method to routine monitoring of surface sanitation. It allows for a reduction in holding times and thereby provides the necessary time to make decisions.
Direct, Sensitive Determination of Trace Amounts of Dissolved Ferric Iron in Natural Water by Light Absorption Ratio Variation Spectrometry
Authors: Gao Hong-Wen , Chen Ling , Yang Qiao-Zhi
Published: February 2020

The chromophore eriochrome cyanine R (ECR) was used to sensitively coordinate Al(III) and Fe(III) in the presence of cetylpyridinium chloride (CPC) at pH 4.8. Trace amounts of Fe(III) can displace Al(III) from the Al(ECR)(CPC) ternary complex to form the Fe(ECR)(CPC) complex. The composition of the complexes was determined by the break point approach. The competitive displacement complexation was sensitive and highly selective, even if no masking reagent was added. An ongoing novel spectrophotometry, named the light-absorption ratio variation approach, was applied to the direct determination of Fe(III) in natural water with recovery between 92.5 and 106%. The detection limit was only 9 ng/mL Fe(III).
Evaluation of Two Procedures to Determine Acid and Neutral Detergent Fibers in Ruminant Feeds of the Temperate Region of Argentina
Authors: Fay José P , Guaita María S , Danelón José L , Chifflet Sonia , Wawrzkiewicz Marisa , Fernández Héctor M , Ross Deborah A
Published: February 2020

The objective of this work was to compare the traditional Van Soest's procedure to analyze neutral detergent fibers (NDF) and acid detergent fibers (ADF) using filtering crucibles (VS) with a semiautomatic method which uses filter bags in an ANKOM Technology Corp. instrument (ANK). Nine ruminant feeds widely used in the temperate region of Argentina were analyzed: soybean meal expeller, alfalfa, pasture silage, ryegrass, corn silage, weeping lovegrass, tall wheatgrass, guinea grass, and barley grass. Four runs were done for each technique and feed. The comparison of ADF and NDF means by the means test for paired samples showed no significant differences between techniques (α = 0.01). The variability among runs was greater with the VS method than the ANK, both for NDF, standard deviation (SD) = 0.71 vs 0.39, and for ADF, SD = 0.83 vs 0.56, but the differences were not significant. The linear regressions were VS = 1.43 + 0.95 ANK; R2 = 0.99, and VS = 0.53 + 0.98 ANK; R2 = 0.99 for NDF and ADF, respectively, which indicated a strong linear relationship among the results of both procedures. It was concluded that the ANK procedure gave results comparable to those of the VS method when ruminant feeds from the temperate region of Argentina were analyzed.
Historical Perspective as a Guide for Identifying and Developing Applicable Methods for Dietary Fiber
Authors: DeVries Jonathan W , Rader Jeanne I
Published: February 2020

A review is presented describing the nature and evolving definition of dietary fiber. The historical development of the current definition is discussed as are the efforts to develop analytical methods to support food labeling regulations. Also considered are the characterization and quantitation of resistance starch, a dietary starch that does not digest in the small intestine, behaves like dietary fiber and therefore may have potential as a health-related ingredient in foods. The current status of AOAC methodology is discussed along with the possibility of updating the definition of dietary fiber. The potential impacts of changing the dietary fiber definition on analytical issues and on food composition databases are also considered.
Species-Specific Polymerase Chain Reaction Amplification of Camel (Camelus) DNA Extracts
Authors: Chen Ying , Wu Ya-Jun , Xu Bao-Liang , Wan Jing , Qian Zeng-Ming
Published: February 2020

A sensitive polymerase chain reaction (PCR) method based on amplification of a specific DNA fragment was established for the identification of camel (Camelus) materials. The species-specific primer pair L183/H372 was designed based on the nucleotide sequence of the mitochondrial cytochrome b gene, and its specificity was confirmed by amplification of 3 camel (domestic double-humped camel, wild double-humped camel, wild one-humped camel) samples and 11 non-Camelus animal (sheep, goat, pig, chicken, cattle, fish, dog, horse, donkey, deer, and rabbit) materials. An expected 208 base pair fragment was amplified from camel materials; no cross-reactive or additional fragments were generated from other animal materials. Taq I restriction endonuclease digestion of the unpurified PCR product can be used routinely to confirm the camel origin of the amplified sequence.
Determination of Low MolecularWeight Alcohols Including Fusel Oil in Various Samples by Diethyl Ether Extraction and Capillary Gas Chromatography
Authors: Woo Kang-Lyung
Published: February 2020

Low molecular weight alcohols including fusel oil were determined using diethyl ether extraction and capillary gas chromatography. Twelve kinds of alcohols were successfully resolved on the HP-FFAP (polyethylene glycol) capillary column. The diethyl ether extraction method was very useful for the analysis of alcohols in alcoholic beverages and biological samples with excellent cleanliness of the resulting chromatograms and high sensitivity compared to the direct injection method. Calibration graphs for all standard alcohols showed good linearity in the concentration range used, 0.001–2% (w/v) for all alcohols. Salting out effects were significant (p < 0.01) for the low molecular weight alcohols methanol, isopropanol, propanol, 2-butanol, n-butanol and ethanol, but not for the relatively high molecular weight alcohols amyl alcohol, isoamyl alcohol, and heptanol. The coefficients of variation of the relative molar responses were less than 5% for all of the alcohols. The limits of detection and quantitation were 1–5 and 10–60 μg/L for the diethyl ether extraction method, and 10–50 and 100–350 g/L for the direct injection method, respectively. The retention times and relative retention times of standard alcohols were significantly shifted in the direct injection method when the injection volumes were changed, even with the same analysis conditions, but they were not influenced in the diethyl ether extraction method. The recoveries by the diethyl ether extraction method were greater than 95% for all samples and greater than 97% for biological samples.
Development and Validation of a Thin-Layer Chromatography-Densitometric Method for the Quantitation of Alliin from Garlic (Allium sativum) and Its Formulations
Authors: Kanaki Niranjan S , Rajani M
Published: February 2020

A selective, precise, and accurate high-performance thin-layer chromatographic (HPTLC) method has been proposed for the analysis of garlic and its formulations for their alliin content. The method involves densitometric evaluation of alliin after resolving it by HPTLC on silica gel plates with n-butanol–acetic acid–water (6 + 2 + 2, v/v) as the mobile phase. For densitometric evaluation, peak areas were recorded at 540 nm after derivatizing the resolved bands with ninhydrin reagent. The relation between the concentration of alliin and corresponding peak areas was found to be linear within the range of 250 to 1500 ng/spot. The method was validated for precision (interday and intraday), repeatablility, and accuracy. Mean recovery was 98.36%. The method was applied for the quantitation of alliin in bulbs of Allium sativum Linn. (garlic) and its formulations. The proposed TLC method was found to be precise, specific, sensitive, and accurate and can be used for routine quality control of garlic and its formulations.
Validation Study of a Lateral-Flow Immunoassay for Detection of Ruminant By-Product Material in Animal Feeds and Feed Ingredients: Performance-Tested MethodSM 010405
Authors: Klein Frank , Lupo Tony , Pielack Don , Mozola Mark , Pinero David , Coates Scott , Thiex Nancy , Holst Christoph von , Drouillard Jim
Published: February 2020

An immunoassay with a lateral flow format has been developed for the detection of ruminant by-product material in animal feeds and feed ingredients. The test is designed for the analysis of animal feeds destined for feeding to ruminants to ensure that they do not contain ruminant by-products in violation of the ruminant-to-ruminant feed ban established by the U.S. Food and Drug Administration in 1997. This feed ban was established as a firewall against exposure of ruminant livestock animals to the prion agents responsible for neurological diseases such as bovine spongiform encephalopathy and scrapie. The test is designed for field use, e.g., at a feed mill, and yields a qualitative (presence/absence) result in 15–20 min. The objective of the study was to validate the lateral-flow test for detection of ruminant by-product material in a variety of finished animal feeds and feed ingredients. Results indicate that the test is specific for ruminant material and can detect as little as 1% ruminant material in these commodities.
Simultaneous Determination of Bifonazole and Tinctures of Calendula Flower in Pharmaceutical Creams by Reversed-Phase Liquid Chromatography
Authors: Ferreyra Carola F , Ortiz Cristina S
Published: February 2020

The aim of this research was to develop and validate a sensitive, rapid, easy, and precise reversed-phase liquid chromatography (LC) method for stability studies of bifonazole (I) formulated with tinctures of calendula flower (II). The method was especially developed for the analysis and quantitative determination of I and II in pure and combined forms in cream pharmaceutical formulations without using gradient elution and at room temperature. The influence on the stability of compound I of temperature, artificial radiation, and drug II used for the new pharmaceutical design was evaluated. The LC separation was carried out using a Supelcosil LC-18 column (25 cm × 4.6 mm id, 5 μm particle size); the mobile phase was composed of methanol–0.1 M ammonium acetate buffer (85 + 15, v/v) pumped isocratically at a flow rate of 1 mL/min; and ultraviolet detection was at 254 nm. The analysis time was less than 10 min. Calibration graphs were found to be linear in the 0.125–0.375 mg/mL (rI = 0.9991) and 0.639–1.916 mg/mL (rII = 0.9995) ranges for I and II, respectively. The linearity, precision, recovery, and limits of detection and quantification were satisfactory for I and II. The results obtained suggested that the developed LC method is selective and specific for the analysis of I and II in pharmaceutical products, and that it can be applied to stability studies.
Simultaneous Spectrophotometric Determination of Paracetamol and Salicylamide in Human Serum and Pharmaceutical Formulations by a Differential Kinetic Method
Authors: Zarei Ali Reza , Afkhami Abbas , Sarlak Nahid
Published: February 2020

A rapid, simple, and sensitive differential kinetic method is presented for the determinations of acetaminophen (also known as paracetamol) and salicylamide. The method is based on their oxidation reaction by Fe3+ ion in the presence of 1,10-phenanthroline as indicator. The reactions can be monitored spectrophotometrically by measuring the increase in the absorbance of the solution at 510 nm. Two times were selected one in which only paracetamol is oxidized by Fe3+ ion and the other in which both drugs are oxidized by Fe3+ ion. The data were evaluated by the proportional equations method. The method allowed the simultaneous determination of paracetamol and salicylamide at concentrations between 0.5–20 and 1–40 μg/mL with relative standard deviations of 3.47 and 2.58%, respectively. The method was applied to the simultaneous determination of paracetamol and salicylamide in human serum and pharmaceutical formulations.
Determination of Spiroxamine Residues in Grapes, Must, and Wine by Gas Chromatography/Ion Trap-Mass Spectrometry
Authors: Tsiropoulos Nicholas G , Liapis Konstantinos , Likas Dimitrios T , Miliadis George E
Published: February 2020

Analytical methodology was developed and validated for the determination of spiroxamine residues in grapes, must, and wine by gas chromatography/ion trap-mass spectrometry (GC/IT-MS). Two extraction procedures were used: the first involved grapes, must, and wine extraction with alkaline cyclohexane–dichloromethane (9 + 1, v/v) solution, and the second grape extraction with acetone, dichloromethane, and petroleum ether. In both procedures, the extract was centrifuged, evaporated to dryness, and reconstituted in cyclohexane or 2,2,4-trimethylpentane–toluene (9 + 1, v/v), respectively. Spiroxamine diastereomers A and B were determined by GC/IT-MS, and a matrix effect was observed in the case of grapes but not in must and wine. Recovery of spiroxamine from fortified samples at 0.02 to 5.0 mg/kg ranged from 78–102% for grapes and must, with relative standard deviation (RSD) <13%; for red and white wines, recoveries ranged from 90 to 101% with RSD <9%. The limit of quantification was 0.02 mg/kg for grapes, must, and wine or 0.10 mg/kg for grapes, depending on the extraction procedure used.
Improved DNA Probe Detection of Listeria monocytogenes in Enrichment Culture After Physical-Chemical Fractionation
Authors: Duvall Robert E , Eklund Marjut , Tran Tony T , Hitchins Anthony D
Published: February 2020

Bacterial detection in foods by nucleic acid probes is limited by microflora competition during selective enrichment. Probe target concentration by extraction and fractionation of enrichments may diminish this limitation. The 1-h AccuProbe chemiluminescent culture identification test for Listeria monocytogenes was used as a model. Its high detection threshold provides a stringent challenge for evaluating enrichmentwork-up protocols. Detection of L. monocytogenes, at 14 colony-forming units/g food,was not consistently possible in 48 h enrichment cultures usingAccuProbe. Concentration by cell sedimentationwas occasionally helpful but the volume of co-sedimented food limited concentration to about 10-fold. To improve concentration, enrichment sedimentswere sonicated or enzymatically lysed to release the probe's target, r-RNA. The RNAwas separated from non-RNA material by extraction with phenol and precipitation with ethanol. Enrichments (250 mL) were concentrated 2500-fold, and the limitation was food RNA volume. A strongly competitive Enterococcus faecium food isolate was used to demonstrate the effect of artificial competition on the kit's ability to detect L. monocytogenes in enrichments. High competitor concentrations repressed the level of the target below the detection threshold, but concentration of r-RNA enabled detection of L. monocytogenes. The effectiveness of this enrichment sample work-up was demonstrated with naturally contaminated hummus.