Methodologies for teaching an engineering subject in different countries: comparison and results

Engineering or technical degrees are difficult to teach and, consequently, have always been characterized by a large number of academic failures. Therefore, continuous assessment has been applied to classes of similar content, related to Port and Coastal Engineering during these last years in three different Universities worldwide: University of La Republica (Montevideo, Uruguay), Nova de Lisboa (Portugal) and Cadiz (Spain). This paper presents different methodologies used to teach and evaluate these courses at each University, together with the results of the evaluations of the students who were enrolled during the current and previous stages. Generally, a decrease in the number of students who abandon the classes has been noticed together with an increase in the percentage of students who pass and an improvement of their grades, except at the University Nova de Lisboa were the results have remained stable. In addition, changes experienced in the courses are discussed herein by comparing the percentage of success in the different locations. Moreover, influence of the different methodologies and the possible reasons for these changes are also presented and analysed. As a conclusion, the improvement in educational outcomes has been achieved through the concurrence of different factors: the existence of more frequent written and/or oral exams, practical examples of case studies as well as access to specific tools of new technology and to documentation specifically prepared for the classes and available online. Evidently, the above mentioned tasks require a strong commitment and great effort by the teaching staff. If human resources diminish, as it is happening in Spain and Portugal due to the budget reduction in education, two difficult questions arise: For how long will teachers’ current effort be maintained? What impact will have their complete devotion to teaching in their research performance

Enantiomeric separation of non-protein amino acids by Electrokinetic Chromatography

New analytical methodologies enabling the enantiomeric separation of a group of non-protein amino acids of interest in the pharmaceutical and food analysis fields were developed in this work using Electrokinetic Chromatography. The use of FMOC as derivatization reagent and the subsequent separation using acidic conditions (formate buffer at pH 2.0) and anionic cyclodextrins as chiral selectors allowed the chiral separation of eight from the ten non-protein amino acids studied. Pyroglutamic acid, norvaline, norleucine, 3,4-dihydroxyphenilalanine, 2-aminoadipic acid, and selenomethionine were enantiomericaly separated using sulfated-alpha-CD while sulfated-gamma-CD enabled the enantiomeric separation of norvaline, 3,4-dihydroxyphenilalanine, 2-aminoadipic acid, selenomethionie, citrulline, and pipecolic acid. Moreover, the potential of the developed methodologies was demonstrated in the analysis of citrulline and its enantiomeric impurity in food supplements. For that purpose, experimental and instrumental variables were optimized and the analytical characteristics of the proposed method were evaluated. LODs of 2.1 x 10(-7) and 1.8 x 10(-7) M for D-and L-citrulline, respectively, were obtained. D-Cit was not detectable in any of the six food supplement samples analyzed showing that the effect of storage time on the racemization of citrulline was negligible. (C) 2016 Elsevier B.V. All rights reserved

Capillary electrophoresis determination of non-protein amino acids as quality markers in foods

Non-protein amino acids mainly exist in food as products formed during food processing, as metabolic intermediates or as additives to increase nutritional and functional properties of food. This fact makes their analysis and determination an attractive field in food science since they can give interesting information on the quality and safety of foods. This article presents a comprehensive review devoted to describe the latest advances in the development of (achiral and chiral) analytical methodologies by capillary electrophoresis and microchip capillary electrophoresis for the analysis of non-protein amino acids in a variety of food samples. Most relevant information related to sample treatment, experimental separation and detection conditions, preconcentration strategies and limits of detection will be provided.Universidad de Alcal

High resolution liquid chromatography tandem mass spectrometry for the separation and identification of peptides in coffee silverskin protein hydrolysates

An analytical methodology was developed for the first time in this work to investigate the peptide composition of coffee silverskin protein hydrolysates. Coffee silverskin is the only by-product produced in the coffee roasting process and it contains a relatively high amount of proteins (16.2-19.0%). Different extraction procedures were tested to obtain protein extracts from coffee silverskin samples which were subsequently submitted to enzymatic digestion using different enzymes. Protein hydrolysates from Arabica coffee silverskin obtained using three roasting degrees (light, medium and dark) were considered in order to evaluate the influence of this process on peptide composition. Antioxidant and hypocholesterolemic activities were investigated for these hydrolysates. A method based on the use of liquid chromatography coupled to a quadrupole-time-of-flight mass spectrometer was developed enabling the separation and identification of different short chain peptides in the coffee silverskin hydrolysates using de novo sequencing tool. Different peptides, with a number of amino acids ranging from 4 to 12, were identified in the coffee silverskin analyzed. Peptides obtained were different depending on the enzymatic hydrolysis employed. As general trend, the results obtained showed that peptide composition in coffee silverskin protein hydrolysates was not significantly affected by the coffee roasting process

Advances in the determination of non-protein amino acids in foods and biological samples by capillary electrophoresis

There are hundreds of non-protein amino acids whose importance in food and biological matrices is still unknown. Many of these compounds mainly exist in food as products formed during food processing, as metabolic intermediates or as additives to increase nutritional and functional properties of food. Moreover, they have also demonstrated to play an important role in the pharmaceutical and clinical fields since they may be used therapeutically in the treatment of some pathologies and their levels may be related with some diseases. For this reason, the analysis of non-protein amino acids may provide relevant information in the food and biological fields. This article reviews the most recent advances in the development of analytical methodologies employing capillary electrophoresis for the achiral and chiral analysis of non-protein amino acids in food and biological samples. With this aim, the most relevant information concerning the separation and detection of these compounds by capillary electrophoresis is discussed and detailed experimental conditions under which their determination was achieved in food and biological samples are given covering the period of time from 2015 to 2018

Separation and identification of peptides in hydrolysed protein extracts from edible macroalgae by HPLC-ESI-QTOF/MS

Macroalgae contain significant amounts of high-quality proteins which, because of their structural diversity, contain a range of yet undiscovered peptides within their primary structures. In this work, an analytical methodology was developed for the separation and identification of peptides present in protein hydrolysates from three different edible macroalgae used for human consumption (Saccharina latissima (brown macroalga), Codium spp. (green macroalga), and Mastocarpus stellatus (red macroalga)). The extraction of aqueous and alkaline soluble proteins was carried out followed by their precipitation with HCl or acetone. The protein extracts obtained were submitted to enzymatic digestion with alcalase and subsequently analyzed by reversed-phase high-performance liquid chromatography-quadrupole-time-of flight mass spectrometry (RP-HPLC-QTOF/MS) and de novo sequencing tool to separate and identify different short chain peptides. Thirty-seven peptides were identified in the hydrolysed protein extracts from the three macroalgae, five of them being common in brown and red macroalgae. After checking against BIOPEP database, several sequenced peptides were found within longer peptides with potential antibacterial activity. Any of the identified peptides had previously been identified in macroalgae

Software Estadístico CHIC: descubriendo sus potencialidades mediante el análisis de percepción sexual universitaria.

El Análisis Estadístico Implicativo es una técnica estadística no paramétrica multivariada para descubrir conocimiento en Bases de Datos mediante R-reglas asimétricas entre variables y clases de variables. Fue descubierta por el francés Regis Gras aproximadamente hace 40 años y está en constante crecimiento en su parte teórica, computacional y aplicaciones. La herramienta computacional que automatiza el Análisis Estadístico Implicativo es llamada CHIC, en el año 2015 se finalizó en la Escuela Superior Politécnica de Chimborazo el desarrollo de su versión libre llamada R-CHIC, su desarrollo estuvo a cargo del francés Raphael Couturier. La metodología utilizada fue la del descubrimiento de conocimiento en bases de datos con el Análisis Estadístico Implicativo aplicado a una base de datos de 198 variables y 100 sujetos. Esta comunicación aporta mostrando la instalación, ejecución y además la aplicación del software estadístico R-CHIC y su interpretación en el contexto de la percepción sexual, por primera ocasión. Como principales resultados se obtuvieron los pasos para la instalación y ejecución de R-CHIC, la aplicación del Análisis Estadístico Implicativo mediante árboles de similaridad, árboles jerárquicos y grafos Implicativos y su interpretación.  Se concluye con interpretaciones interesantes a la percepción sexual estudiantil basadas en el software R-CHIC mediante reglas de relación simétricas y asimétricas en forma rápida, visual, intuitiva y comprensible

Capillary electrophoresis-mass spectrometry metabolic fingerprinting of green and roasted coffee

The aim of this work was to develop a capillary electrophoresis-mass spectrometry (CE-ESI-QToF-MS) method to carry out the metabolic fingerprinting of green and roasted coffee samples (Arabica variety). To evaluate changes in the metabolic profiles of coffee occurring along the roasting process, green coffee beans were submitted to different roasting degrees. The effect of different parameters concerning the electrophoretic separation (background electrolyte, temperature, voltage, and injection time), the MS detection (temperature and flow of drying gas, sheath gas of jet stream temperature, and capillary, fragmentator, nozzle, skimmer, and octapole voltages) and the sheath liquid (composition and flow rate) was studied to achieve an adequate separation and to obtain the largest number of molecular features. The analyses were carried out in positive ESI mode allowing to detect highly polar cationic metabolites present in coffee beans. Non-supervised and supervised multivariate analyses were performed showing a good discrimination among the different coffee groups. Those features having a high variable importance in the projection values on supervised analyses were selected as significant metabolites for their identification. Thus, 13 compounds were proposed as potential markers of the coffee roasting process, being 7 of them tentatively identified and 2 of them unequivocally identified. Different families of compounds such as pyridines, pyrroles, betaines, or indoles could be pointed out as markers of the coffee roasting process. (C) 2019 Elsevier B.V. All rights reserved

Untargeted HILIC-MS-based metabolomics approach to evaluate coffee roasting process: contributing to an integrated metabolomics multiplatform

An untargeted metabolomics strategy using hydrophilic interaction chromatography-mass spectrometry (HILIC-MS) was developed in this work enabling the study of the coffee roasting process. Green coffee beans and coffee beans submitted to three different roasting degrees (light, medium, and strong) were analyzed. Chromatographic separation was carried out using water containing 10 mM ammonium formate with 0.2 % formic acid (mobile phase A) and acetonitrile containing 10mM ammonium formate with 0.2% formic acid (mobile phase B). A total of 93 molecular features were considered from which 31 were chosen as the most statistically significant using variable in the projection values. 13 metabolites were tentatively identified as potential biomarkers of the coffee roasting process using this metabolomic platform. Results obtained in this work were complementary to those achieved using orthogonal techniques such as reversed-phase liquid chromatography-mass spectrometry (RPLC-MS) and capillary electrophoresis-mass spectrometry (CE-MS) since only one metabolite was found to be common between HILIC-MS and RPLC-MS platforms (caffeoylshikimic acid isomer) and other between HILIC-MS and CE-MS platforms (choline). On the basis of these results, an untargeted metabolomics multiplatform is proposed in this work based on the integration of the three orthogonal techniques as a powerful tool to expand the coverage of the roasted coffee metabolome

A non-targeted metabolomic approach based on reversed-phase liquid chromatography-mass spectrometry to evaluate coffee roasting process

In this work, a non-targeted metabolomics approach based on the use of reversed-phase liquid chromatography coupled to a high-resolution mass spectrometer has been developed to provide the characterization of coffee beans roasted at three different levels (light, medium, and dark). In this way, it was possible to investigate how metabolites change during the roasting process in order to identify those than can be considered as relevant markers. Twenty-five percent methanol was selected as extracting solvent since it provided the highest number of molecular features. In addition, the effect of chromatographic and MS parameters was evaluated in order to obtain the most adequate separation and detection conditions. Data were analyzed using both non-supervised and supervised multivariate statistical methods to point out the most significant markers that allow group discrimination. A total of 24 and 33 compounds in positive and negative ionization modes, respectively, demonstrated to be relevant markers; most of them were from the hydroxycinnamic acids family