Automated method using direct-immersion solid-phase microextraction and on-fiber derivatization coupled with comprehensive two-dimensional gas chromatography high-resolution mass spectrometry for profiling naphthenic acids in produced water.

Naphthenic acids (NAs) are naturally occurring organic acids in petroleum and are found in waste waters generated during oil production (produced water, PW). Profiling this class of compounds is important due to flow assurance during oil exploration. Compositional analysis of PW is also relevant for waste treatment to reduce negative impacts on the environment. Here, comprehensive two-dimensional gas chromatography coupled with high-resolution mass spectrometry (GC×GC-HRMS) was applied as an ideal platform for qualitative analysis of NAs by combining the high peak capacity of the composite system with automated scripts for group-type identification based on accurate mass measurements and fragmentation patterns. To achieve high-throughput profiling of NAs in PW samples, direct-immersion solid phase microextraction (DI-SPME) was selected for extraction, derivatization and preconcentration. A fully automated DI-SPME method was developed to combine extraction, fiber rinsing and drying, and on-fiber derivatization with N-methyl-N­tert-butyldimethylsilyltrifluoroacetamide (MTBSTFA). Data processing was based on filtering scripts using the Computer Language for Identifying Chemicals (CLIC). The method successfully identified up to 94 NAs comprising carbon numbers between 6 and 18 and hydrogen deficiency values ranging from 0 to -4. The proposed method demonstrated wider extraction coverage compared to traditional liquid-liquid extraction (LLE) - a critical factor for petroleomic investigations. The method developed also enabled quantitative analysis, exhibiting detection limits of 0.5 ng L-1 and relative standard deviation (RSD) at a concentration of NAs of 30 µg L-1 ranging from 4.5 to 25.0%.

Direct analysis of naphthenic acids in produced water and crude oil by NH2-surface-modified wooden-tip electrospray ionization mass spectrometry.

This work describes the surface coating of wooden toothpicks with amino groups (NH2) for electrospray ionization mass spectrometry (MS) analysis of naphthenic acids (NAs) in produced water samples and crude oil fractions. NH2 was introduced into the cellulosic material through a silanization reaction using aminopropyltriethoxysilane. An NH2-modified toothpick was inserted into the analyte extraction sample and was subsequently used as an electrospray emitter for MS analysis. The extraction conditions were optimized by analyzing NAs (benzoic acid, 1-naphthoic acid, decanoic acid, 3,5-dimethyladamantane-1-carboxylic acid, and 3,5-dimethyladamantane-1-acetic acid) in pure water, and the best condition was using 5 min of extraction time with the samples under agitation. Modified and unmodified wooden toothpicks were compared, and the intensities of all NAs were higher when using the modified substrates than when using the unmodified ones. Limit of detection (LOD), limit of quantification (LOQ), linearity, precision, and recovery were determined by analyzing decanoic acid in seawater samples. The LOD and LOQ were 2 and 5 µg mL-1, respectively, and a linear correlation (R2 = 0.9927) was obtained with concentrations ranging from 5 to 250 µg mL-1. Precision values ranged from 6 to 13% and recoveries from 89 to 106%. The technique was also employed to analyze three produced water samples, in which decanoic acid was semi-quantified, and the concentrations ranged from 10 to 13 µg mL-1. High abundances of acidic compounds of class O2 with DBEs (double bond equivalents) ranging from 1 to 3 and carbon numbers going from 8 to 12 were detected in the produced water samples. The results suggest that the modification of wooden toothpicks with NH2 might offer a significant advancement in the knowledge of cheap substrates that can improve the sensitivity of analysis of NAs in water samples.

Isolation of diterpenes from Araucaria sp Brazilian brown propolis and development of a validated high-performance liquid chromatography method for its analysis.

Propolis comprises a complex resinous product composed of plant's parts or exudates, pollen, bee wax, and enzymes. Brazilian brown propolis from Araucaria sp displays several biological activities. Considering the lack of validated analytical methods for its analysis, we are reporting the development of a validated high-performance liquid chromatography with photodiode array detector method to analyze Araucaria brown propolis. The crude propolis were extracted and chromatographed, furnishing six main diterpenes. The isolated standards were used to draw the analytical curves, allowing the studies of selectivity, precision, accuracy, recovery, robustness, the determination of limits of detection and limits of quantification. The mobile phase consisted of 0.1% acetic acid in water and acetonitrile, using an octadecylsilane column, 1 mL/min flow rate and detection at 200 or 241 nm. Relative standard deviation values obtained for intra-day and inter-day precision were lower than 4% for all diterpenes. From the five parameters for robustness, wavelength detection and flow rate were the critical ones. Limits of detection and quantification ranged from 0.808 to 10.359 µg/mL and from 2.448 to 31.392 µg/mL, respectively. The recoveries were between 105.03 and 108.13%, with relative standard deviation values around 5.0%. The developed method is precise, sensitive, and reliable for analyzing Araucaria brown propolis.

Organic acids produced during fermentation and sensory perception in specialty coffee using yeast starter culture.

Volatile and non-volatile compounds in coffee directly affect the beverage's quality. This study aimed to demonstrate how the organic acids and volatile profiles were impacted by coffee fermentation using four starter cultures (Meyerozyma caribbica (CCMA 0198), Saccharomyces cerevisiae (CCMA 0543), Candida parapsilosis (CCMA0544), and Torulaspora delbrueckii (CCMA 0684)) inoculated in two varieties of coffee (Bourbon Amarelo and Canário Amarelo) using natural and pulped natural processing methods and sensory perception. Real-time PCR (qPCR) was used to verify the dynamic behavior of yeast populations. Organic acids were detected using high performance liquid chromatography (HPLC) and gas chromatography-mass spectrometry (GC-MS) was used to detected volatile compounds. Sensory analysis was performed on the roasted coffee. Citric, malic, succinic, lactic, oxalic, isobutyric, and propionic acids and 105 volatile compounds were detected. At the beginning of fermentation, treatments with natural processing presented higher number of volatiles compounds. After fermentation, the main compounds groups were acids, alcohols, and aldehydes. The perception of sensory attribute (fruity, nutty, cocoa) varied with the coffee variety, type of processing, and type of inoculum. The use of yeasts is an alternative for sensorial differentiation of coffee variety Canário Amarelo and Bourbon Amarelo. The stainless-steel containers showed good results for coffee fermentation.

Assessing the performance of electrochemical oxidation using DSA® and BDD anodes in the presence of UVC light.

Significance of surface and ground water contamination by synthetic organic compounds has been pointed out in a very high number of papers worldwide, as well as the need of application of treatment technologies capable to assure their complete removal. Among these processes, the electrochemical advanced oxidation is an interesting option, especially when irradiated with UVC light (photo-electrochemical, P-EC) to promote homolysis of electrogenerated oxidants. In this work, the herbicide glyphosate (GLP) was used as model compound and it was electrochemically treated under UVC irradiation in the presence of NaCl and using a DSA® and BDD anodes. Total organic carbon concentration was measured throughout the electrolysis, as well as the concentration of short chain carboxylic acids and inorganic ions (NO3-, PO43-,ClO-, ClO3- and ClO4-). The synergism of the P-EC was more pronounced when using a DSA® electrode, which led to complete GLP mineralization in 1 h (0.52 A h L-1), as also confirmed by the stoichiometric formation of NO3- and PO43- ions, with an energy consumption as low as 1.25 kW h g-1. Unexpectedly, the concentration evolution of oxyhalides for the P-EC process using both anodes, especially for DSA® at 10 mA cm-2, showed the production of ClO3-, whereas detection of ClO4- species was only found when using BDD at 100 mA cm-2 for the electrochemical process. Finally, small amounts of carboxylic acids were detected, including dichloroacetic acid, especially when using a BDD electrode.

Using scrap zero valent iron to replace dissolved iron in the Fenton process for textile wastewater treatment: Optimization and assessment of toxicity and biodegradability.

A Fenton like advanced oxidation process (AOP) employing scrap zerovalent iron (SZVI) and hydrogen peroxide (H2O2) was studied for industrial textile wastewater treatment from a textile manufacturing plant located at Medellín, Colombia (South America). The wastewater effluent studied contains a mixture of organic compounds resistant to conventional treatments. The effect of initial pH and SZVI concentration and H2O2 concentration were studied by a response surface methodology (RSM) Box-Behnken design of experiment (BBD). The combined SZVI/H2O2 process led to reductions of 95% color, 76% of chemical oxygen demand (COD) and 71% of total organic carbon (TOC) at optimal operating conditions of pH = 3, SZVI = 2000 mg/L and [H2O2] = 24.5 mM. Molecular weight distribution measurement (MWD), ultraviolet-visible (UV-Vis) spectroscopy, HPLC, biodegradability and toxicity were used to characterize the pollutants after the treatment process finding that the resulting effluent was polluted mostly by low molecular weight carboxylic acids. A remarkable biodegradability enhancement of the effluent was evidenced by a BOD5/COD ratio increase from 0.22 to 0.4; also, the SZVI/H2O2 process successfully reduced the toxicity from 60% to 20% of dead A. Salina crustaceans.

1H NMR-based fingerprinting of eleven Mexican Capsicum annuum cultivars.

Approximately 90% of the chili peppers consumed in the world are harvested in Mexico. The present article describes the untargeted 1H NMR-based metabolomic profiling of 11 cultivars of Capsicum annuum species which are routinely consumed worldwide. The metabolomic fingerprinting detected via 1H NMR contained 44 metabolites including sugars, amino acids, organic acids, polyphenolic acids and alcohols which were identified by comparison with the literature data, with Chenomx database and by 2D NMR. Statistical approaches based on principal component analysis (PCA) and linear discriminant analysis (LDA) were used to classify the Capsicum annuum cultivars according to their metabolite profile. LDA revealed metabolomic differences and similarities among Capsicum annuum cultivars, whereas hierarchical cluster analysis (HCA) significantly separated the cultivars according to the phylogenetic trees obtained. Substantial endogenous levels of free amino acids and carbohydrates were detected in all the studied cultivars but interestingly, Capsicum annuum cv. mirasol and C. annuum cv. chilaca contained almost three-fold more endogenous levels of vitamin C than the other cultivars. Considering that this antioxidant was found in crude aqueous extracts, its abundance could be directly proportional to its bioavailability for human nutrition. The results suggest that 1H NMR is an effective method to determine differences among cultivars of the Capsicum annuum species.

The Acid/Base Profile of a Large Food Chemical Database.

Molecular acid/base properties have a significant influence on membrane permeation, metabolism, absorption, and affinity for biological targets. In particular, ionizable groups are critical in the strength of target-molecule interactions, pharmacokinetics, and toxicity. In this study, we estimated the acid/base properties of the food chemicals from FooDB, a public compound collection with more than 22,000 compounds. It was found that the food chemicals have 40.9 % of neutral compounds, which is twice as many as that found in approved drugs. The most common functional groups among the acid groups in the food chemicals were phenols (16.1 %), phosphates (17.3 %), and carboxylates (17.3 %) while the single-base-containing compounds were of less interest as they accounted for just 5.5 %. To the best of our knowledge, this is the first systematic acid/base profiling of food chemicals and it is part of a continued effort to profile food chemicals for their broad interest in several areas such as nutrition and the food industry in general.

Simultaneous voltammetric determination of four organic acids in fruit juices using multiway calibration.

A sensitive, fast, and inexpensive square wave voltammetric method using a cobalt phthalocyanine modified carbon paste electrode was developed for simultaneous determination of citric, lactic, malic and tartaric acids in fruit juices. To overcome the strong overlap of voltammetric signals caused by calibrated and uncalibrated constituents, multivariate curve resolution with alternating least squares (MCR-ALS) was used. Data were previous treated for correction of baseline and potential shift. The MCR-ALS calibration models were constructed and evaluated using a validation set obtained from a Taguchi design. The values predicted by the optimized MCR-ALS models were unbiased and no statistically significant difference was observed between proposed and reference methods, applying the paired t-test at a confidence level of 95%. As far as the authors know, a voltammetric method that simultaneously determines four organic acids in complex samples such as fruit juices without any previous pretreatment has not yet been reported in the literature.

Sulfluramid use in Brazilian agriculture: A source of per- and polyfluoroalkyl substances (PFASs) to the environment.

N-Ethyl perfluorooctane sulfonamide (EtFOSA) is a perfluorooctane sulfonate (PFOS) precursor and the active ingredient in sulfluramid, a pesticide which is used extensively in Brazil for management of leaf cutting ants. Here we investigate the occurrence of EtFOSA, PFOS, and other per- and polyfluoroalkyl substances (PFASs) in soil, eucalyptus leaves, water (ground, riverine, and coastal (estuarine/marine)) and coastal sediment from an agricultural region of Bahia State, Brazil. This area contains a larger number of eucalyptus plantations where sulfluramid is suspected to be applied. Soil, leaves, and coastal water (marine/estuarine) contained ∑PFAS concentrations of up to 5400 pg g-1, 979 pg g-1, and 1020 pg L-1, respectively, with PFAS profiles generally dominated by PFOS and perfluorooctane sulfonamide (FOSA). Coastal sediment contained ∑PFAS concentrations of up to 198 pg g-1, with PFOS, FOSA, and perfluorooctanoic acid (PFOA) being the most frequently observed PFASs. These substances are all potential EtFOSA transformation products, pointing to sulfluramid as a possible source. In riverine water, ∑PFAS concentrations of up to 8930 pg L-1 were observed. PFOS and PFOA were detected in all river water samples. Groundwater also exhibited PFAS contamination (5730 pg L-1 ∑PFASs), likely from sulfluramid use. The observation of other PFASs (e.g. perfluorobutanoic acid) in freshwater suggests that other PFAS sources (in addition to sulfluramid) may be important in this region. Overall, these data support the hypothesis that sulfluramid use contributes to the occurrence of PFASs in the Brazilian environment.

Fruit sugar and organic acid were significantly related to fruit Mg of six citrus cultivars.

The fruit quality of 6 citrus cultivars growing in the same orchard was determined at ripening stage in both 2014 and 2015. We further measured the components of sugar (sucrose, fructose and glucose), organic acid (citric, malate and quinic acid), enzymes related to Glycolysis and Krebs cycle and mineral elements at 5 stages of fruit development in the second year. The results showed that at ripening stage of both years, 'Newhall' cultivar had higher TSS concentration and the TSS/TA ratio but lower TA concentration, while 'Flame' cultivar was exactly opposite. Sucrose and citric acid were the most accumulated compounds in fruit during the fruit development of 6 citrus cultivars. Fruit sucrose concentration increased from 9.26 mg·kg-1 at 60 DAFB to 50.92 mg·kg-1 at 180 DAFB, and the citric acid concentration increased from 1.41 mg·kg-1 at 60 DAFB to 29.87 mg·kg-1 at 90 DAFB or 29.02 mg·kg-1 at 120 DAFB then decreased till ripening (5.47 mg·kg-1). We found ACO was the key enzyme resulting in the difference of citric acid accumulation, but not quite clear in sucrose metabolism. The fruit mineral nutrient concentrations of 6 cultivars during the fruit development were 0.94-1.92% of N, 0.11-0.23% of P, 1.03-1.37% of K, 0.31-1.15% of Ca, 0.11-0.29% of Mg, 3.97-72.34 mg·Fe kg-1, 1.93-10.64 mg·Mn kg-1, 1.56-10.73 mg·Cu kg-1, and 0.90-16.80 mg·Zn kg-1. We also analyzed the relationship among each sugar, organic acid component and mineral nutrient in this study by curve estimation and PCA analysis. The results indicated that only Mg was significantly correlated with both sugar and organic acid component, negative and positive respectively. It suggested that the accumulation of sugar and organic acid might be related to the dynamic changes of fruit Mg concentrations of 6 citrus cultivars.

The effect of methanogenesis inhibition, inoculum and substrate concentration on hydrogen and carboxylic acids production from cassava wastewater.

Manipueira is a carbohydrate-rich agro-industrial waste from cassava processing. It is considered well suitable for biotechnological processes, such as hydrogen and carboxylic acids production, due to the high content of easily degradable organic matter. However, the proper methanogenesis inhibition method, inoculum type, and organic loads are factors still limiting the processes. The objective in this work was to evaluate the effects of such factors on byproducts production in anaerobic reactors. Batch experiments were conducted with 2.3-L flasks during two operational phases. In the first phase (P1), inhibition of methanogens in the sludge was evaluated using acetylene (1% v/v of headspace) and heat treatment (120 °C, 1 atm for 30 min). In the second phase (P2), three inoculum types obtained from common anaerobic sludges (bovine rumen and sludges from municipal and textile industrial wastewater treatment plants) were individually assayed. P2 aimed to identify the best inoculum, based on hydrogen production ability, which was tested for three initial concentrations of manipueira in terms of chemical oxygen demand (COD) (10, 20 and 40 g O2/L). Results of P1 indicated that either acetylene or heat treatment efficiently inhibited methanogenesis, with no methane production. However, the maximum H2 production potential by applying heat treatment (~ 563 mL) was more than twice compared with that by acetylene treatment (~ 257 mL); and butyrate was the main carboxylic acid by-product (~ 3 g/L). In P2 experiments after sludge heat treatment, the highest hydrogen yield (1.66 ± 0.07 mol H2/mol glucose) and caproic acid production (~ 2 g/L) were observed at 20 g O2/L of manipueira COD, when bovine rumen was the inoculum. The primary metabolic degradation products in all P2 experiments were ethanol, acetic, butyric, propionic and caproic acids. The finding of caproic acid detection indicated that the applied conditions in manipueira anaerobic degradation favored carbon chain elongation over methanogenesis.

Electrochemical mineralization of cephalexin using a conductive diamond anode: A mechanistic and toxicity investigation.

The contamination of surface and ground water by antibiotics is of significant importance due to their potential chronic toxic effects to the aquatic and human lives. Thus, in this work, the electrochemical oxidation of cephalexin (CEX) was carried out in a one compartment filter-press flow cell using a boron-doped diamond (BDD) electrode as anode. During the electrolysis, the investigated variables were: supporting electrolyte (Na2SO4, NaCl, NaNO3, and Na2CO3) at constant ionic strength (0.1 M), pH (3, 7, 10, and without control), and current density (5, 10 and 20 mA cm-2). The oxidation and mineralization of CEX were assessed by high performance liquid chromatography, coupled to mass spectrometry and total organic carbon. The oxidation process of CEX was dependent on the type of electrolyte and on pH of the solution due to the distinct oxidant species electrogenerated; however, the conversion of CEX and its hydroxylated intermediates to CO2 depends only on their diffusion to the surface of the BDD. In the final stages of electrolysis, an accumulation of recalcitrant oxamic and oxalic carboxylic acids, was detected. Finally, the growth inhibition assay with Escherichia coli cells showed that the toxicity of CEX solution decreased along the electrochemical treatment due to the rupture of the ß-lactam ring of the antibiotic.

Microchip electrophoresis for wine analysis.

The present critical review provides a summary of representative articles describing the analysis of wine by microchip electrophoresis. Special emphasis has been given to those compounds able to provide background information to achieve the differentiation of wines according to botanical origin, provenance, vintage and quality or assure wine authentication. This review focuses on capillary electrophoresis (CE) microchips dedicated to the analysis of wine covering all the contributions concerning this area. The most relevant compounds in wine analysis such as phenols, organic acids, inorganic species, aldehydes, sugars, alcohols, and neuroactive amines were considered. Moreover, a special section is dedicated to the potential of CE microchip for wine classification. Indeed, potential directions for the future are discussed.

A North American and global survey of perfluoroalkyl substances in surface soils: Distribution patterns and mode of occurrence.

The distribution of 32 per/polyfluoroalkyl substances (PFASs) in surface soils was determined at 62 locations representing all continents (North America n = 33, Europe n = 10, Asia n = 6, Africa n = 5, Australia n = 4, South America n = 3 and Antarctica n = 1) using ultra performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) systems. Quantifiable levels of perfluoroalkyl carboxylates (PFCAs: PFHxA-PFTeDA) were observed in all samples with total concentrations ranging from 29 to 14,300 pg/g (dry weight), while perfluoroalkane sulfonates (PFSAs: PFHxS, PFOS and PFDS) were detected in all samples but one, ranging from

Simultaneous analysis of carbohydrates and organic acids by HPLC-DAD-RI for monitoring goat's milk yogurts fermentation.

During yogurt manufacture, the lactose fermentation and organic acid production can be used to monitor the fermentation process by starter cultures and probiotic bacteria. In the present work, a simple, sensitive and reproducible high-performance liquid chromatography with dual detectors, diode array detector and refractive index was validated by simultaneous analysis of carbohydrates and organic acids in goat milk yogurts. In addition, pH and bacterial analysis were performed. Separation of all the compounds was performed on an Aminex HPX-87H column (300×7.8 mm, 9 µm) utilizing a 3 mmol L(-1) sulfuric acid aqueous mobile phase under isocratic conditions. Lactose, glucose, galactose, citric, lactic and formic acids were used to evaluate the following performance parameters: selectivity, linearity, precision, limit of detection (LOD), limit of quantification (LOQ), decision limits (CCα), detection capabilities (CCß), recovery and robustness. For the method application a six goat milk yogurts were elaborated: natural, probiotic, prebiotic, symbiotic, cupuassu fruit pulp, and probiotic with cupuassu fruit pulp. The validated method presented an excellent selectivity with no significant matrix effect, and a broad linear study range with coefficients of determination higher than 0.995. The relative standard deviation was lower than 10% under repeatability and within-laboratory reproducibility conditions for the studied analytes. The LOD of the method was defined from 0.001 to 0.003 µg g(-1), and the LOQ from 0.003 to 0.013 µg g(-1). The CCα was ranged from 0.032 to 0.943 µg g(-1), and the CCß from 0.053 to 1.604 µg g(-1). The obtained recovery values were from 78% to 119%. In addition, the method exhibited an appropriate robustness for all parameter evaluated. Base in our data, it was concluded that the performance parameters demonstrated total method adequacy for the detection and quantification of carbohydrates and organic acids in goat milk yogurts. The application of the method was successfully applied to monitoring different goat milk yogurts during fermentation.

Alcoholic fermentation of Saccharomyces cerevisiae, Pichia stipitis and Zymomonas mobilis in the presence of inhibitory compounds and seawater.

Production of cellulosic ethanol and holocellulosic ethanol from vegetable or microbial biomass starts with a hydrolysate containing compounds which may produce negative effects in the enzymatic hydrolysis and fermentation stages due to the need of pretreatment of the materials. In this way, the simultaneous presence of hydroxymethylfurfural (HMF), furfural, acetic acid, levulinic acid, and formic acid in different concentrations was tested in the fermentation using Saccharomyces cerevisiae, Pichia stipitis, and Zymomonas mobilis. The substitution of freshwater by seawater in the culture medium was also analyzed. Thus, inhibitory effects were stronger in the fermentation using P. stipitis, followed by Z. mobilis and S. cerevisiae. Formic acid and acetic acid presented more significant effects among the inhibitory compounds, followed by HMF, furfural and levulinic acid. Fermentation performed in culture medium with seawater showed promising results, especially in the ethanol yield using S. cerevisiae (0.50 g ethanol/g glucose) and Z. mobilis (0.49 g ethanol/g glucose). Whereas the production of cellulosic ethanol and holocellulosic ethanol are in early stages of development on an industrial scale, and that the availability and use of freshwater may cause socio-environmental problems for expansion of ethanol production, the use of seawater appears as an alternative to mitigate this problem.

Identification of unknown colorants in pre-Columbian textiles dyed with American cochineal (Dactylopius coccus Costa) using high-performance liquid chromatography and tandem mass spectrometry.

The present study concerns the identification of nine thus-far unknown derivatives of carminic acid extracted from pre-Columbian Peruvian textiles dyed with American cochineal-these derivatives are not found in commercially available preparations of the dye. These compounds probably represent a unique fingerprint of dyed textiles from this region, as they have never been reported to occur in other fabrics of historical value. They were separated by reversed-phase high-performance liquid chromatography (phenyl column) and detected using a UV/vis spectrophotometer and two tandem mass spectrometers. Peaks observed in chromatograms registered at 450 and 500 nm were further identified by ESI QqQ MS (mainly in the negative ion mode), supported by high-resolution ESI QIT/ToF MS data. The characteristic fragmentation pathways of isolated carminic acid and its derivatives provided additional information concerning lost neutrals and thus the functional groups and substituents present in the parent molecules. This information mainly related to multiple cleavages of the hexoside moiety (initially cross-ring cleavage), which are characteristic of C-glucosides (loss of 90, 120, and 148 Da). This is accompanied by the elimination of H2O as well as the further loss of 60 Da from the hexoside moiety. Moreover, other losses from the carbonyl groups (44 Da from CO2 loss, 62 Da from ethylene glycol loss, 32 Da from O2 loss, 138 Da from hydroxybenzoic acid, and 120 Da from oxomethylene cyclohexadienone) provided more specific information about structures of the identified derivatives of carminic acid.

Microbiological and chemical characteristics of Brazilian kefir during fermentation and storage processes.

The microbial community composition and chemical characteristics of a Brazilian milk kefir sample produced during its manufacturing and refrigerated storage were investigated by culture-dependent and -independent methods and HPLC. Lactococcus lactis ssp. cremoris and ssp. lactis, Leuconostoc mesenteroides, Acetobacter lovaniensis, and Saccharomyces cerevisiae were isolated, whereas the detected bands on denaturing gel gradient electrophoresis corresponded to Lactobacillus kefiranofaciens, Lactobacillus kefiri, Lactobacillus parakefiri, and S. cerevisiae. After fermentation, lactic acid bacteria were present at levels of 10 log units, whereas acetic acid bacteria and yeast were present at levels of 7.8 and 6 log units, respectively. The lactic acid bacteria and yeast counts remained constant, whereas acetic acid bacteria counts decreased to 7.2 log units during storage. From fermentation to final storage, the pH, lactose content and citric acid of the kefir beverage decreased, followed by an increase in the concentrations of glucose, galactose, ethanol, and lactic, acetic, butyric, and propionic acids. These microbiological and chemical characteristics contribute to the unique taste and aroma of kefir. This research may serve as a basis for the future industrial production of this beverage in Brazil.

Electrochemical incineration of omeprazole in neutral aqueous medium using a platinum or boron-doped diamond anode: degradation kinetics and oxidation products.

The electrochemical incineration of omeprazole, a widely prescribed gastrointestinal drug which is detected in natural waters, has been studied in a phosphate buffer of pH 7.0 by anodic oxidation with electrogenerated H(2)O(2) (AO-H(2)O(2)) operating at constant current density (j). The experiments were carried out in a cell equipped with either a Pt or a boron-doped diamond (BDD) anode and an air-diffusion cathode to continuously produce H(2)O(2). In these systems, organics are mainly oxidized by hydroxyl radicals formed at the Pt or BDD surface from water oxidation. A partial total organic carbon (TOC) abatement close to 78% for omeprazole was achieved by AO-H(2)O(2) with a BDD anode after consumption of 18 Ah L(-1) at 100 mA cm(-2), whereas the alternative use of Pt did not allow mineralizing the drug. However, the drug was totally removed using both anodes, although it decayed more rapidly using BDD. In this latter system, increasing j accelerated the degradation process, but lowering the mineralization current efficiency. Greater drug content also enhanced the degradation rate with higher mineralization degree and current efficiency. The kinetics for omeprazole decay always followed a pseudo-first-order reaction and its rate constant increased with increasing j and with decreasing its concentration. Seven heteroaromatic intermediates and four hydroxylated derivatives were detected by LC-MS, while nine short-linear carboxylic acids were identified and quantified by ion-exclusion HPLC. These acids were largely accumulated using Pt and rapidly removed using BDD, thus explaining the partial mineralization of omeprazole achieved by AO-H(2)O(2) with the latter anode. The release of inorganic ions such as NO(3)(-), NH(4)(+) and SO(4)(2-) was followed by ionic chromatography. A plausible reaction sequence for omeprazole mineralization involving all intermediates detected is proposed.