0000000000002437
AUTHOR
María Jesús Lerma-garcía
showing 54 related works from this author
Use of linear discriminant analysis applied to vibrational spectroscopy data to characterize commercial varnishes employed for art purposes.
2007
An improvement of methodologies for characterising synthetic resins used in varnishes employed for art purposes has been suggested. Several kinds of standard of the most common polymeric resins (acrylic, vinyl, poly(vinyl alcohol), alkyd, cellulose nitrate, latex, polyester, polyurethane, epoxy, organosilicic, and ketonic) were analyzed by Fourier transform infrared (FTIR) spectroscopy. Synthetic resins characterization is based on the mathematical treatment of their whole spectrum, dividing it in 13 sections, avoiding the one-by-one interpretation of the absorption bands. The mathematical model takes as variables the maximal absorbance of each section, and each synthetic standard resin as …
Use of electronic nose to determine defect percentage in oils. Comparison with sensory panel results
2010
Abstract An electronic nose based on an array of 6 metal oxide semiconductor sensors was used, jointly with linear discriminant analysis (LDA) and artificial neural network (ANN) method, to classify oils containing the five typical virgin olive oil (VOO) sensory defects (fusty, mouldy, muddy, rancid and winey). For this purpose, these defects, available as single standards of the International Olive Council, were added to refined sunflower oil. According to the LDA models and the ANN method, the defected samples were correctly classified. On the other hand, the electronic nose data was used to predict the defect percentage added to sunflower oil using multiple linear regression models. All …
Classification of vegetable oils according to their botanical origin using amino acid profiles established by direct infusion mass spectrometry.
2007
Amino acid profiles, established by direct infusion mass spectrometry, have been used to classify vegetable oils according to their botanical origin. The proteins present in hazelnut, sunflower, corn, soybean, olive, avocado, peanut and grapeseed oils were precipitated with acetone, and the residue was hydrolyzed in acid medium, diluted in a hydrochloric acid/ethanol mixture, and infused into the mass spectrometer. The spectra of the hydrolyzed protein extracts showed [M+H]+ ions of the following amino acids: glycine, alanine, serine, proline, valine, threonine, cysteine, isoleucine + leucine, aspartic acid, lysine, glutamic acid, methionine, histidine, phenylalanine, arginine and tyrosine.…
Authentication of extra virgin olive oils by Fourier-transform infrared spectroscopy
2010
Fourier-transform infrared spectroscopy (FTIR), followed by multivariate treatment of the spectral data, was used to classify vegetable oils according to their botanical origin, and also to establish the composition of binary mixtures of extra virgin olive oil (EVOO) with other low cost edible oils. Oil samples corresponding to five different botanical origins (EVOO, sunflower, corn, soybean and hazelnut) were used. The wavelength scale of the FTIR spectra of the oils was divided in 26 regions. The normalized absorbance peak areas within these regions were used as predictors. Classification of the oil samples according to their botanical origin was achieved by linear discriminant analysis (…
Orange proteomic fingerprinting: From fruit to commercial juices.
2015
Combinatorial peptide ligand library technology, coupled to mass spectrometry, has been applied to extensively map the proteome of orange pulp and peel and, via this fingerprinting, to detect its presence in commercial orange juices and drinks. The native and denaturing extraction protocols have captured 1109 orange proteins, as identified by LC-MS/MS. This proteomic map has been searched in an orange concentrate, from a Spanish juice manufacturer, as well as in commercial orange juices and soft drinks. The presence of numerous orange proteins in commercial juices has demonstrated the genuineness of these products, prepared by using orange fruits as original ingredients. However, the low nu…
Methacrylate ester-based monolithic columns for nano-LC separation of tocopherols in vegetable oils
2010
The separation and determination of tocopherols (Ts) in vegetable oils by nano-LC chromatography with UV-vis detection using lauryl methacrylate ester-based monolithic columns has been developed. The separation of Ts was optimized in terms of mobile phase composition on the basis of the best compromise among efficiency, resolution and analysis time. Using a mobile phase composed of ACN/methanol/water, an excellent resolution between Ts was achieved within 18 min. The LODs were lower than 0.26 μg/mL, being repeatability values of retention time and peak area below 0.15 and 3.1%, respectively. The method was applied to the quantification of Ts and tocotrienols present in several vegetable oil…
Prediction of the curing time of Spanish hams using peptide profiles established by capillary zone electrophoresis
2009
Abstract A capillary zone electrophoresis procedure for the prediction of curing time of Spanish hams using peptide profiles has been developed. Excellent resolution between the seven peptide peaks was achieved within 30 min analysis time with a BGE containing 60 mM MgSO 4 and 50 mM phosphate at pH 2.5. Using hams with curing times of 6, 8 and 12 months, both linear discriminant analysis (LDA) and multiple linear regression (MLR) models were constructed. In both cases, two different normalisation procedures of the peak areas were compared. Using LDA, all the ham samples corresponding to the three categories were correctly classified. Using MLR, the ham curing time could be predicted with av…
Prediction of the genetic variety of Spanish extra virgin olive oils using fatty acid and phenolic compound profiles established by direct infusion m…
2007
Abstract The genetic varieties of Spanish extra virgin olive oils (Arbequina, Hojiblanca and Picual) were predicted by direct infusion of the samples in the electrospray ionization source of a mass spectrometer, followed by linear discriminant analysis of the spectral data. The samples were 1:50 diluted (v/v) with an 85:15 propanol/methanol (v/v) mixture containing 40 mM KOH and infused. The abundances of the [M–H] − peaks of the free fatty acids (7 peaks) and 28 phenolic compounds (20 peaks) were measured. Ratios of pairs of peak abundances were used as predictors in the construction of the linear discriminant analysis models. An excellent resolution between the three genetic varieties was…
Chemical analysis and antioxidant activity of the essential oils of three Piperaceae species growing in the central region of Cuba.
2013
The present study describes the phytochemical profile and antioxidant activity of the essential oils of three Piperaceae species collected in the central region of Cuba. The essential oils of Piper aduncum, P. auritum and P. umbellatum leaves, obtained by hydrodistillation, were analyzed by gas chromatography-mass spectrometry. The main components of P. aduncum oil were piperitone (34%), camphor (17.1%), camphene (10.9%), 1,8-cineol (8.7%) and viridiflorol (7.4%), whereas that of P. auritum and P. umbellatum was safrole (71.8 and 26.4%, respectively). The antioxidant properties of the essential oils were also evaluated using several assays for radical scavenging ability (DPPH test and redu…
Rapid differentiation of commercial juices and blends by using sugar profiles obtained by capillary zone electrophoresis with indirect UV detection.
2015
A method for the determination of sugars in several fruit juices and nectars by capillary zone electrophoresis with indirect UV-vis detection has been developed. Under optimal conditions, commercial fruit juices and nectars from several fruits were analyzed, and the sugar and cyclamate contents were quantified in less than 6 min. A study for the detection of blends of high-value juices (orange and pineapple) with cheaper alternatives was also developed. For this purpose, different chemometric techniques, based on sugar content ratios, were applied. Linear discriminant analysis showed that fruit juices can be distinguished according to the fruit type, juice blends also being differentiated. …
Efficient Extraction of Olive Pulp and Stone Proteins by using an Enzyme-Assisted Method
2014
An efficient protein extraction protocol for proteins from olive pulp and stone by using enzymes was developed. For this purpose, different parameters that affect the extraction process, such as enzyme type and content, pH, and extraction temperature and time, were tested. The influence of these factors on protein recovery was examined using the standard Bradford assay, while the extracted proteins were characterized by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). The best extraction conditions were achieved at pH 7.0 and 5% (v/v) Palatase® 20000 L (lipase) for pulp and Lecitase® Ultra (phospholipase) for stone proteins. The optimal extraction temperature and time w…
Metal oxide semiconductor sensors for monitoring of oxidative status evolution and sensory analysis of virgin olive oils with different phenolic cont…
2009
An electronic nose based on an array of six metal oxide semiconductor sensors was used to monitor the oxidative status of virgin olive oils (VOO) during storage. VOO samples, with and without phenolic compounds, were stored at 60 °C for 7 weeks. Once a week, absorbance at 232 and 270 nm, oxidized stability index, electronic nose, and sensory analysis were evaluated. Linear discriminant analysis models were constructed in order to classify samples according to oxidative levels. Based on these models, VOO samples with and without phenolic compounds at different storage times, divided in eight categories, were correctly classified also achieving a good correlation for sensory analysis. The met…
Rapid determination of sterols in vegetable oils by CEC using methacrylate ester-based monolithic columns
2008
A method for the determination of sterols in vegetable oils by CEC with UV-Vis detection, using methacrylate ester-based monolithic columns, has been developed. To prepare the columns, polymerization mixtures containing monomers of different hydrophobicities were tried. The influence of composition of polymerization mixture was optimized in terms of porogenic solvent, monomers/porogens and monomer/crosslinker ratios. The composition of the mobile phase was also studied. The optimum monolith was obtained with lauryl methacrylate monomer at 60:40% (wt:wt) lauryl methacrylate/ethylene dimethacrylate ratio and 60 wt% porogens with 20 wt% of 1,4-butanediol (12 wt% 1,4-butanediol in the polymeriz…
IMPACT OF THE "COMUNICAT" METHODOLOGY ON THE IMPROVEMENT OF THE "EFFECTIVE ORAL COMMUNICATION" STUDENT OUTCOME OF THE STUDENTS OF THE MASTER IN FOOD …
2019
[EN] During academic course 2017-2018 the Comunica't methodology was created to help students to self-learn all the skills needed to master the areas of domain of the general student outcome effective oral communication. After two academic years of implementation, the goal of this work is to analyse the degree of contribution of this methodology to development of the "Effective Oral Communication students outcome of students that followed the methodology during the subject Audits of Food Safety and Quality Systems, belonging to the Master in Food Safety and Quality Management. To this end, at the beginning of the subject, students were asked to present a topic related to the subject and eva…
According to the CPLL proteome sheriffs, not all aperitifs are created equal!
2014
Combinatorial peptide ligand libraries (CPLLs) have been adopted for investigating the proteome of a popular aperitif in Northern Italy, called "Amaro Branzi", stated to be an infusion of a secret herbal mixture, of which some ingredients are declared on the label, namely Angelica officinalis, Gentiana lutea and orange peel, sweetened by a final addition of honey. In order to assess the genuineness of this commercial liqueur, we have prepared extracts of the three vegetable ingredients, assessed their proteomes, and compared them to the one found in the aperitif. The amaro's proteome was identified via prior capture with CPLLs at two different pH values (2.2 and 4.8). Via mass spectrometry …
Characterization of the alcoholic fraction of vegetable oils by derivatization with diphenic anhydride followed by high-performance liquid chromatogr…
2008
Abstract Aliphatic and triterpene alcohols present in vegetable oils have been identified and determined by HPLC using UV–vis and MS detection after previous derivatization with diphenic anhydride. The alcoholic fraction was obtained by saponification, extraction and TLC (according to the European Union official procedure). Derivatization was performed in tetrahydrofuran in the presence of suspended grinded urea, which increases the reaction rate and yield. Derivatized extracts were chromatographed on a C8 column using gradient elution with acetonitrile/water mixtures containing 0.1% acetic acid, with UV–vis followed by negative-ion mode MS detection. Using linear discriminant analysis of t…
Phenolic profiles of olive mill wastewaters treated by membrane filtration systems
2014
BACKGROUND Olive mill wastewater is an important by-product obtained after olive oil extraction. In this investigation, the phenolic composition of olive mill wastewater treated with a semi-industrial membrane filtration system, including ultrafiltration and reverse osmosis modules, was studied. In particular, untreated olive mill wastewater was compared with the permeate and the concentrate fractions of each filtration step. RESULTS 3,4-(dihydroxyphenyl) ethanol and p-(hydroxyphenyl) ethanol were the main compounds of all olive mill wastewater analyzed. A total of 32 compounds, detected at 240 or 280 nm by HPLC-DAD, were considered for phenol quantification. Ultrafiltration reduced phenol …
Capillary Electrophoresis of Free Fatty Acids by Indirect Ultraviolet Detection: Application to the Classification of Vegetable Oils According to The…
2011
A method for the determination of fatty acids in vegetable oils by capillary electrophoresis with indirect UV–vis detection has been developed. The separation of fatty acids was optimized in terms of Brij surfactant nature and concentration and organic modifier (2-propanol) percentage. The optimal background electrolyte consisted of 10 mM p-hydroxybenzoate, 5 mM Tris at pH 8.8, 80 mM Brij 98, 40% acetonitrile, and 10% 2-propanol. Under these conditions, vegetable oils from five botanical origins (avocado, corn, extra virgin olive, hazelnut, and soybean) were analyzed and the fatty acid contents established. Linear discriminant analysis (LDA) models were constructed using fatty acid peak are…
Quality control of fruit juices by using organic acids determined by capillary zone electrophoresis with poly(vinyl alcohol)-coated bubble cell capil…
2015
An enhanced method for the determination of organic acids in several fruit juices by capillary zone electrophoresis (CZE) with direct UV-Vis detection has been developed in this work. First, a study with simulated real juice samples was done to find the best separation conditions. Next, several commercial fruit juices were analyzed, and the organic acid contents were quantified in less than 12 min using a poly(vinyl alcohol)-coated fused-silica 'bubble cell' capillary. The present method is reliable, fast and provides detection limits comprised between 0.1 and 2.5 μg mL(-1). Moreover, different chemometric techniques, based on CZE data, were examined. Linear discriminant analysis allowed th…
Classification of extra virgin olive oils according to their geographical origin using phenolic compound profiles obtained by capillary electrochroma…
2009
Abstract A simple and reliable method for the evaluation of the phenolic fraction of extra virgin olive oils (EVOO) by capillary electrochromatography (CEC) with UV–Vis detection, using lauryl acrylate (LA) ester-based monolithic columns, has been developed. The percentages of the porogenic solvents in the polymerization mixture, and the mobile phase composition, were optimized. The optimum monolith was obtained with a monomers/porogens ratio of 40:60% (wt/wt) using a LA/1,3-butanediol diacrylate ratio of 70:30% (wt/wt) and a 1,4-butanediol/1-propanol ratio of 25:75% (wt/wt). A satisfactory resolution between the phenolic compounds was achieved in less than 25 min with a 15:85 (v/v) ACN–wat…
ACTIVITIES TO PROMOTE THE SELF-LEARNING OF THE EFFECTIVE COMMUNICATION STUDENT OUTCOME
2018
[EN] Universities all over the world are implementing a competence-based type of teaching and learning to guarantee certain student learning outcomes at the end of the studies. To reach these student outcomes, active methodologies should be included in teaching practice at the same time that carefully designed rubrics might be used for the evaluation of the students. Despite the fact that teachers introduce more and more authentic tasks in the classroom, these activities are not still well employed by all the University teaching staff. The goal of this work is to propose a guideline of activities to promote the self-learning of the effective communication outcome by the students. For that p…
Solid-phase extraction based on ground methacrylate monolith modified with gold nanoparticles for isolation of proteins
2015
In this study, a novel polymeric material functionalized with gold nanoparticles (AuNPs) was prepared as solid-phase extraction (SPE) sorbent for isolation of proteins. The sorbent was synthesized from a powdered poly(glycidyl-co-ethylene dimethacrylate) monolith, and modified with ammonia, followed by immobilization of AuNPs on the pore surface of the material. To evaluate the performance of this SPE support, proteins were selected as test solutes, being the extraction conditions and other parameters (loading capacity and regenerative ability of sorbent) established. The results indicated that this sorbent could be employed to selectively capture proteins according to their pI, on the basi…
Use of gold nanoparticle-coated sorbent materials for the selective preconcentration of sulfonylurea herbicides in water samples and determination by…
2012
Abstract Two new gold nanoparticle (NP) coated materials (silica supported on gold NP with and without ionic liquid) were synthesized for solid phase extraction of sulfonylurea herbicides (SUHs), such as bensulfuron-methyl (BSM), metsulfuron-methyl (MSM), pyrazosulfuron-methyl (PSM), thifensulfuron-methyl (TFM) and triasulfuron (TS), from water samples, followed by capillary liquid chromatography coupled to diode array detection (CLC–DAD). Several factors influencing the preconcentration efficiency of SUHs and its subsequent determination, such as pH of the sample, eluent and reusability of sorbents, have been investigated. Under the optimum conditions, the developed method allowed the dete…
Evaluation of the quality of olive oil using fatty acid profiles by direct infusion electrospray ionization mass spectrometry
2008
Abstract Electrospray ionization mass spectrometry is used to predict the olive oil quality according to European Union marketing standards. Samples were 1:50 diluted in an alkaline 85:15 (v/v) propanol/methanol mixture and directly infused into the electrospray ionization source of an ion trap mass spectrometer. The establishment of ratios of the peak abundances of the free fatty acids followed by linear discriminant analysis was employed to predict the olive oil quality grade. In addition, using multiple linear regression and partial least-squares regression, the percentages of extra virgin and virgin olive oils in binary mixtures were predicted with 5–11% average prediction errors.
Presence of palm oil in foodstuffs: consumers' perception
2019
Purpose The purpose of this paper is to determine the presence of palm oil in food products on sale, and to study and compare consumers’ opinions about this oil type in Spain (importing country) and Peru (producing country). Design/methodology/approach Recent news published in both countries, which could influence consumer perceptions, were analysed. A study on the labelling of foodstuffs in Spain was carried out, as was a survey with Spanish and Peruvian consumers. Findings Palm oil was found in a large number of products and in a wide range of foods, especially those from the bakery sector. The percentages of saturated fats varied substantially within the same product type. Spanish consu…
Determination of tocopherols in vegetable oils by CEC using methacrylate ester-based monolithic columns
2007
The separation and determination of tocopherols (Ts) in vegetable oils by CEC using methacrylate ester-based monolithic columns has been developed. The effects of pore size of the monolithic columns were studied, and the composition of mobile phase was optimized. The optimal pore size of the monolith was obtained with 12 wt% 1,4-butanediol in the polymerization mixture. Excellent resolution between tocopherols was achieved within 10 min analysis time with a 99:1 v/v MeOH-aqueous buffer containing 5 mM tris(hydroxymethyl)aminomethane at pH 8.0. The LODs were lower than 2.3 microg/mL, and interday and column-to-column reproducibilities at 25 microg/mL were better than 5.6%. Using a 93:7 v/v M…
Study of chemical changes produced in virgin olive oils with different phenolic contents during an accelerated storage treatment.
2009
Chemical changes produced in an extra virgin olive oil sample in the presence (EVOO) and absence (EVOOP) of its phenolic fraction during an accelerated storage treatment at 60 degrees C up to 7 weeks were studied. Modifications in phenol content, as well as changes in several quality parameters (free acidity, peroxide value, UV absorbance, fatty acid composition, oxidative stability index, and tocopherol content) were also evaluated under the same storage conditions and compared to those of the same sample deprived of phenolic compounds. When the phenolic extract of the EVOO was studied, a decrease of the antioxidants first present in the sample and an increase of the oxidized products were…
Classification of pumpkin seed oils according to their species and genetic variety by attenuated total reflection Fourier-transform infrared spectros…
2011
Attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), followed by multivariate treatment of the spectral data, was used to classify seed oils of the genus Cucurbita (pumpkins) according to their species as C. maxima, C. pepo, and C. moschata. Also, C. moschata seed oils were classified according to their genetic variety as RG, Inivit C-88, and Inivit C-2000. Up to 23 wavelength regions were selected on the spectra, each region corresponding to a peak or shoulder. The normalized absorbance peak areas within these regions were used as predictors. Using linear discriminant analysis (LDA), an excellent resolution among all categories concerning both Cucurbita species a…
Proteomic fingerprinting of mistletoe (Viscum album L.) via combinatorial peptide ligand libraries and mass spectrometry analysis
2017
Abstract Combinatorial peptide ligand libraries (CPLLs), coupled to mass spectrometry (MS) analysis, have been used to investigate in depth the proteome of Viscum album L. (VA), commonly named European mistletoe, in order to provide a first proteomic fingerprinting. For this purpose, the proteins were captured via CPLLs at two different pH values (acidic and neutral). A total of 648 non-redundant proteins were identified by using two different databases. The two pH values, chosen for bead incubations, have contributed to increment the capture ability: 56% and 31% of CPLLs species were respectively recognized at pH 7.2 and at pH 2.2. Finally the biological function of identified proteins was…
Enzyme-assisted extraction of proteins from Citrus fruits and prediction of their cultivar using protein profiles obtained by capillary gel electroph…
2017
Abstract The suitability of protein profiles established by capillary gel electrophoresis (CGE) as a tool to discriminate between 11 cultivars of Citrus (orange and tangerine) peel and pulp was evaluated in this work. Before CGE analysis, different extraction buffers (which included enzyme-assisted treatments) were compared. The best results were achieved using 5% ( v/v ) Celluclast ® 1.5 L and 5% ( v/v ) Palatase ® 20,000 L buffers for Citrus peel and pulp protein extracts, respectively. The resulting protein profiles obtained were used to construct linear discriminant analysis (LDA) models able to distinguish Citrus peel and pulp samples according to their cultivar. In both cases, all sam…
Classification of vegetable oils according to their botanical origin using n-alkane profiles established by GC-MS.
2013
n-Alkane profiles established by gas chromatography-mass spectrometry (GC-MS) were used to classify vegetable oils according to their botanical origin. The n-alkanes present in corn, grapeseed, hazelnut, olive, peanut and sunflower oils were isolated by means of alkaline hydrolysis followed by silica gel column chromatography of the unsaponifiable fractions. The n-alkane fraction was constituted mainly of n-alkanes in the range C8-C35, although only those most abundant (15 n-alkanes, from 21 to 35 carbon No.) were used as original variables to construct linear discriminant analysis (LDA) models. Ratios of the peak areas selected by pairs were used as predictors. All the oils were correctly …
Use of protein profiles established by CZE to predict the cultivar of olive leaves and pulps
2014
Intact protein profiles established by CZE have been used to predict the cultivar of olive leaves and pulps. For this purpose, proteins were extracted using a mild enzyme-assisted extraction method, which provided higher protein recoveries and a lower environmental impact than other previously described methods. These extracts were subjected to CZE determination under basic conditions using a BGE composed of 50 mM phosphate, 50 mM tetraborate and 0.1% PVA at pH 9. Nine and 14 common peaks, for leaf and pulp samples, respectively, were identified in the nine cultivars studied in this work. In addition, and using linear discriminant analysis of the CZE data, olive leaf and pulp samples belong…
Boronate affinity sorbents based on thiol-functionalized polysiloxane-polymethacrylate composite materials in syringe format for selective extraction…
2021
Abstract In this work, two novel boronate affinity monolithic materials able to extract glycopeptides within a polypropylene syringe are described and compared. The first material was synthesized from glycidyl methacrylate (GMA)-based monoliths modified with poly-3-mercaptopropyl-methylsiloxane (PMPMS) followed by attachment of 4-vinylphenylboronic acid (VPBA) via thiol-ene click reaction. The second material was prepared by using gold nanoparticle (AuNP)-modified monoliths as substrate followed by subsequent attachment of PMPMS and VPBA. The resulting materials were used as sorbents for solid-phase extraction (SPE) to selectively preconcentrate glycopeptides from horseradish peroxidase (HR…
Recent advances in aptamer-based miniaturized extraction approaches in food analysis
2021
Abstract Sample preparation is a relevant step in food analysis to achieve adequate extraction and preconcentration of target analytes before their introduction in the analytical system. Current trends in sample preparation involve moving towards miniaturized extraction devices combined with advanced affinity-based sorbents. Within affinity-based materials, aptamer-based ones have attracted much attention due to their excellent molecular recognition properties, high stability, and the possibility of immobilization onto the surface of different supporting materials, such as nanoparticles, monolithic stationary phases, etc. This review gives an overview of the literature published regarding a…
Rapid Evaluation of Oxidized Fatty Acid Concentration in Virgin Olive Oils Using Metal Oxide Semiconductor Sensors and Multiple Linear Regression
2009
This works aims to set up a rapid and nondestructive method to evaluate the advanced oxidation of virgin olive oils (VOOs). An electronic nose based on an array of six metal oxide semiconductor sensors was used, jointly with multiple linear regression (MLR), to predict the oxidized fatty acid (OFA) concentration in VOO samples characterized by different oxidative status. An MLR model constructed using five predictors was able to predict OFA concentration with an average validation error of 9%.
Classification of Extra Virgin Olive Oils Produced at La Comunitat Valenciana According to Their Genetic Variety Using Sterol Profiles Established by…
2009
A method to classify extra virgin olive oils (EVOOs) according to their genetic variety using sterol profiles obtained by high-performance liquid chromatography (HPLC) with mass spectrometry (MS) detection has been developed. Sterol extracts were chromatographed on a dC18 Atlantis column (100x3 mm, 3 microm) with a gradient of acetonitrile/water (0.01% acetic acid) at a flow rate of 1.0 mL min(-1) and positive-ion mode MS detection. Using linear discriminant analysis of the HPLC-MS data (extracted ion chromatograms), EVOO samples belonging to six genetic varieties cultivated at La Comunitat Valenciana, Spain (Arbequina, Borriolenca, Canetera, Farga, Picual, and Serrana), were correctly clas…
Determination of antibiotics in meat samples using analytical methodologies: A review
2021
Antibiotics are widely used to prevent or treat some diseases in human and veterinary medicine and also as animal growth promoters. The presence of these compounds in foods derived from food-producing animals can be a risk for human health. Consequently, regulatory agencies have set maximum residue limits for antibiotics in food samples. Therefore, the development of novel methodologies for its determination in food samples is required. Specifically, the analysis and quantification of these substances in meat tissues is a challenge for the analytical chemistry research community. This is due to the complexity of the matrix and the low detection limits required by the regulatory agencies. In…
Classification of extra virgin olive oils according to their genetic variety using linear discriminant analysis of sterol profiles established by ult…
2011
Abstract A method to classify extra virgin olive oils (EVOOs) according to their genetic variety using sterol profiles obtained by ultra-performance liquid chromatography (UPLC) with atmospheric pressure chemical ionization mass spectrometry (APCI-MS) detection has been developed. The optimal separation conditions were obtained using a gradient acetonitrile/water (0.01% acetic acid) at a flow rate of 0.8 mL min − 1 and 10 °C. Linear discriminant analysis (LDA) models were constructed with the 11 UPLC-APCI-MS sterol peaks taken from the selective ion recording mode chromatograms. Ratios of the peak areas selected by pairs were used as predictors. With the sequential application of two LDA mo…
Preparation and evaluation of lauryl methacrylate monoliths with embedded silver nanoparticles for capillary electrochromatography
2012
In this article, capillary columns constituted by lauryl methacrylate monoliths with embedded silver nanoparticles (AgNPs) were developed and tested. Two incorporation approaches of AgNPs in monoliths were explored. The AgNPs were either photogenerated in situ during polymerization of the monolith by UV irradiation, or incorporated to the polymerization mixture (ex situ). The influence of the AgNP concentration on the morphological and chromatographic properties of the polymer matrix was investigated, and both the in situ and ex situ approaches were comparatively discussed. The morphology of the monoliths was characterized by electron microscopic techniques, and their electrochromatographic…
Poly(ethylene glycol) diacrylate-based solid-phase extraction for determination of sulfonamides in meat samples
2020
Abstract In this work, a sorbent based on poly(ethylene glycol) diacrylate (PEGDA) polymer has been synthesized for solid-phase extraction (SPE) of sulfonamides (sulfaguanidine, sulfadiazine, sulfathiazole, sulfapyridine, sulfamethazine, sulfamonomethoxine, sulfamethoxazole, sulfisoxazole) from different meat matrices, which were subsequently determined by HPLC-DAD. Several extraction parameters such as loading and elution solvents as well as other variables (loading capacity, breakthrough volume and reusability) influencing on the analytical performance of the sorbent were optimized. Under the optimal conditions, the developed method was successfully applied to determine the eight sulfonam…
Classification of Pecorino cheeses produced in Italy according to their ripening time and manufacturing technique using Fourier transform infrared sp…
2010
Fourier-transform infrared spectroscopy, followed by linear discriminant analysis of the spectral data, was used to classify Italian Pecorino cheeses according to their ripening time and manufacturing technique. The Fourier transform infrared spectra of the cheeses were divided into 18 regions and the normalized absorbance peak areas within these regions were used as predictors. Linear discriminant analysis models were constructed to classify Pecorino cheeses according to different ripening stages (hard and semi-hard) or according to their manufacturing technique (fossa and nonfossa cheeses). An excellent resolution was achieved according to both ripening time and manufacturing technique. A…
Chemical Composition, Antioxidant Properties and Antimicrobial Activity of the Essential Oil of Murraya Paniculata Leaves from the Mountains of Centr…
2012
The essential oil of Murraya paniculata L leaves from the mountains of the Central Region of Cuba, obtained by hydrodistillation, was analyzed by gas chromatography-mass spectrometry. Eighteen compounds, accounting for 95.1% of the oil were identified. The major component was β-caryophyllene (ca. 30%). The antioxidant activity of essential oil was evaluated against Cucurbita seed oil by peroxide, thiobarbituric acid and p-anisidine methods. The essential oil showed stronger antioxidant activity than that of butylated hydroxyanisole and butylated hydroxytoluene, but lower than that of propyl gallate. Moreover, this antioxidant activity was supported by the complementary antioxidant assay in…
Fast Separation and Determination of Sterols in Vegetable Oils by Ultraperformance Liquid Chromatography with Atmospheric Pressure Chemical Ionizatio…
2010
A method for the determination of sterols in vegetable oils by ultraperformance liquid chromatography (UPLC) with atmospheric pressure chemical ionization mass spectrometry detection has been developed. The separation of sterols was optimized in terms of mobile phase composition, column temperature and flow rate. The optimal conditions were achieved using an Acquity UPLC BEH C18 column (50 x 2.1 mm, 1.7 microm) with a mobile phase consistent of acetonitrile/water (0.01% acetic acid) using a linear gradient, at a flow rate of 0.8 mL min(-1) and column temperature of 10 degrees C, giving a total analysis time below 5 min. The determination was performed in selective ion recording mode. The li…
Current trends in affinity-based monoliths in microextraction approaches: A review
2019
Abstract This article reviews the research contributions along the past five years concerning to monolithic materials for the development of affinity-based sorbents in the field of microextraction techniques. The first part of this paper includes an introduction regarding monolithic affinity media and information of different binding agents (such as immunoglobulin-binding proteins, enzymes, lectins, antibodies, aptamers, dyes and immobilized metal ions and nanoparticles, among others) that can act as affinity ligands. Then, the preparation of monoliths and ligand immobilization strategies as well as the different available formats (syringes, pipette tips, spin columns, capillaries, disks an…
Rapid evaluation of oxidised fatty acid concentration in virgin olive oil using Fourier-transform infrared spectroscopy and multiple linear regression
2011
Abstract Fourier-transform infrared spectroscopy (FTIR), followed by multivariate treatment of spectral data, was used to evaluate the oxidised fatty acid (OFA) concentration in virgin olive oil samples characterised by different oxidative status. The entire FTIR spectra (4000–700 cm−1) of oils were divided in 25 wavelength regions. The normalised absorbances of the peak areas within these regions were used as predictors. In order to predict the OFA concentration, multiple linear regression (MLR) models were performed. After a cube root transformation of data, an MLR model constructed using eight predictors was able to predict OFA concentration with an average error of 17%. The main wavelen…
Use of triacylglycerol profiles established by high performance liquid chromatography with ultraviolet–visible detection to predict the botanical ori…
2011
A method for the determination of triacylglycerols (TAGs) in vegetable oils from different botanical origins by HPLC with UV–vis detection has been developed. Using a core-shell particle packed column (C18, 2.6 micron), TAG separation was optimized in terms of mobile phase composition and column temperature. Using isocratic elution with acetonitrile/n-pentanol at 10 °C, excellent efficiency with good resolution between most of the TAG peak pairs, within a total analysis time of 15 min, was achieved. Using mass spectrometry detection, a total of 15 peaks, which were common to oils of six different botanical origins (corn, extra virgin olive, grapeseed, hazelnut, peanut and soybean) were iden…
Acrylate ester-based monolithic columns for capillary electrochromatography separation of triacylglycerols in vegetable oils
2011
Abstract A simple and reliable method for the evaluation of triacylglycerols (TAGs) in vegetable oils by capillary electrochromatography (CEC) with UV–Vis detection, using octadecyl acrylate (ODA) ester-based monolithic columns, has been developed. The percentages of the porogenic solvents in the polymerization mixture, and the mobile phase composition, were optimized. The optimum monolith was obtained at the following ratios: 40:60% (wt/wt) monomers/porogens, 60:40% (wt/wt) ODA/1,3-butanediol diacrylate and 23:77% (wt/wt) 1,4-butanediol/1-propanol (14 wt% 1,4-butanediol in the polymerization mixture). A satisfactory resolution between TAGs was achieved in less than 12 min with a 65:35 (v/v…
Classification of vegetable oils according to their botanical origin using amino acid profiles established by High Performance Liquid Chromatography …
2010
Abstract A preliminary study using amino acid profiles to classify oils according to their botanical origin has been performed. Amino acid profiles were obtained from hydrolysis of proteins present in vegetable oils, and established by High Performance Liquid Chromatography (HPLC) with UV–vis detection. Proteins present in hazelnut, corn, soybean, olive, avocado, peanut and grapeseed oils were precipitated with acetone, and the residue was hydrolysed in acid medium. The amino acids obtained were derivatized with o -phthaldialdehyde and separated by HPLC. Peaks corresponding to 18 amino acids were observed using a C18 column and a gradient of acetonitrile–water in the presence of a 5 mM citr…
Composition, industrial processing and applications of rice bran γ-oryzanol
2009
Abstract Rice bran oil (RBO) (20–25 wt% in rice bran) is a unique rich source of commercially-important bioactive phytochemicals, most of them of interest in nutrition, pharmacy and cosmetics. The unsaponifiable constituents of RBO include mainly tocols (vitamin E, 0.10–0.14%) and γ-oryzanol (esters of trans- ferulic acid with sterols and triterpenic alcohols, 0.9–2.9%). The following topics concerning γ-oryzanol are reviewed: analytical methods for characterisation and determination; influence of genetic and environmental factors on the composition of rice bran; extraction approaches, including supercritical CO 2 and subcritical water; and biomedical and industrial applications, including …
Proteomic fingerprinting of apple fruit, juice, and cider via combinatorial peptide ligand libraries and MS analysis
2018
Combinatorial peptide ligand libraries coupled to MS was applied to extensively map the proteome of apple fruit, and to detect its presence in commercial apple juice and cider to evaluate their authenticity and genuineness. Using the Uniprot_Malus database, 96 proteins were detected in apples, among which 30 proteins were specifically captured via combinatorial peptide ligand libraries. Next, three proteins, previously recognized in fruits, were found in apple juice, which were involved in cellular metabolism of fruit maturation and in allergenic reactions. On the other hand, only one Malus allergen was identified in cider beads eluate, demonstrating that the industrial processes did not pr…
Application of a self-learning methodology for the enhancement of the oral communication student outcome in International Business studies
2019
[EN] Effective oral communication is one of the most demanded student outcomes in the labour market, especially for degree students on International Business. Although this outcome is usually evaluated in several subjects along the curriculum, it is barely worked neither inside nor outside the classroom, mainly due to lack of time and to unavailability of proper learning methodologies. The PIMECOE project, an innovation and educational improvement project on this matter, has developed a self-learning methodology on the Effective Oral Communication student outcome, in which auto-diagnosis tests, selflearning tools and peer assessments are conveniently combined to enhance the proficiency leve…
Determination of water-soluble vitamins in energy and sport drinks by micellar electrokinetic capillary chromatography
2016
Abstract A method for the determination of water-soluble vitamins in several energy and sport drinks by micellar electrokinetic chromatography (MEKC) has been developed in this work. The separation of vitamins was studied in terms of background electrolyte composition (borate content, pH, surfactant type and content) and in other MEKC parameters. A study of the possible compounds found in the vitamin-enriched drinks that could interfere in vitamin determination was also performed, and a modified procedure with enhanced resolution was developed. The proposed method was successfully applied to the analysis of water-soluble vitamins in a variety of energy and sport drinks and also in fruit nec…
Use of an enzyme-assisted method to improve protein extraction from olive leaves.
2013
The improvement of protein extraction from olive leaves using an enzyme-assisted protocol has been investigated. Using a cellulase enzyme (Celluclast® 1.5L), different parameters that affect the extraction process, such as the influence and amount of organic solvent, enzyme amount, pH and extraction temperature and time, were optimised. The influence of these factors was examined using the standard Bradford assay and the extracted proteins were characterised by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE). The optimum extraction parameters were: 30% acetonitrile, 5% (v/v) Celluclast® 1.5L at pH 5.0 and 55°C for 15min. Under these conditions, several protein extracts…
Tannin analysis of chestnut bark samples (Castanea sativa Mill.) by HPLC-DAD-MS.
2014
In the present investigation, an HPLC-DAD/ESI-MS method for the complete analysis of tannins and other phenolic compounds of different commercial chestnut bark samples was developed. A total of seven compounds (vescalin, castalin, gallic acid, vescalagin, 1-O-galloyl castalagin, castalagin and ellagic acid) were separated and quantified, being 1-O-galloyl castalagin tentatively identified and found for the first time in chestnut bark samples. Thus, this method provided information regarding the composition and quality of chestnut bark samples, which is required since these samples are commercialised due to their biochemical properties as ingredients of food supplements.