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Antioxidant activity can be evaluated using cyclic voltammetry (CV). The aim of this work is to verify the efficacy of CV in evaluating the synergistic effect of bioactive compounds, such as phenolic and amino acid compounds, on antioxidant activity. Therefore, three types of model solutions were prepared: individual model solution (phenol and amino acid), (b) binary model solutions (phenol-phenol and amino acid-amino acid) and (c) mixed phenol–amino acid solutions. Electrochemical measurement conditions were optimized for phenolic compounds (pH 3.0, 1.0 g/L and 100 mV/s) and for amino acids (pH 7.0, 2.0 g/L for amino acids and 100 mV/s), and, for each solution, the functional groups responsible of the anodic and cathodic peaks were established. The peak anodic potential (Epa) and the onset potential (Eon) were two parameters of great importance. The first one was used to classify the solutions according to their antioxidant potential. In general, all the binary and mixed solutions had lower values of Epa than the corresponding individual model solution, which indicates an improvement in the antioxidant potential. The second one was used to evaluate the synergistic effects of phenolic compounds and amino acids.

A lo largo del proceso de elaboración del vino se generan grandes cantidades de residuos que, debido a su composición química, constituyen un punto de interés en la industria vitivinícola por los diversos beneficios que pueden aportar. La posibilidad de que estos residuos puedan ser utilizados en nuevos procesos hace que sean considerados subproductos y que se reduzca la contaminación que supondría su eliminación. La utilización de los subproductos de vinificación en el propio proceso de vinificación puede mejorar la calidad del vino.

El presente Trabajo Fin de Grado se centra en la importancia del aparato olfativo en el proceso de identificación de aromas y la relevancia del análisis sensorial y la cromatografía de gases acoplada a la olfatometría (GC-O). Para ello se ha realizado un estudio bibliográfico desde los comienzos de la identificación de los aromas, hasta las últimas aportaciones científicas en el campo del análisis instrumental. El interés por los aromas se inicia desde los tiempos prehistóricos y ha ido de la mano del desarrollo de la industria de las fragancias y de las técnicas sensoriales de análisis de los alimentos. El aparato olfativo posee una alta capacidad para identificar sustancias odorantes y una sensibilidad superior a la de las técnicas instrumentales. La estructura química de estas sustancias está ligada a su aroma y a su umbral de percepción, además pequeños cambios estructurales aportan aromas diferentes. En la identificación de estas moléculas odorantes el panel de evaluadores analíticos juega un papel fundamental, tanto en el análisis sensorial, como en la GC-O, y requiere de proceso de selección y entrenamiento previo al desarrollo del análisis. El estudio biográfico realizado de las aplicaciones de la GC-O pone de manifiesto los aspectos más destacados sobre las técnicas de extracción de odorantes, las técnicas olfatométricas utilizadas y el número de panelistas utilizados, entre otros aspectos., This Final Degree Project focuses on the importance of the olfactory apparatus in the process of identifying aromas and the relevance of sensory analysis and gas chromatography coupled to olfactometry (GC-O). For this purpose, a bibliographic study has been carried out from the beginnings of the identification of aromas to the latest scientific contributions in the field of instrumental analysis. The interest in aromas began in prehistoric times and has gone hand in hand with the development of the fragrance industry and sensory techniques of food analysis. The olfactory apparatus has a high capacity to identify odorant substances and a sensitivity higher than that of instrumental techniques. The chemical structure of these substances is linked to their aroma and their perception threshold, and small structural changes bring different aromas. In the identification of these odorant molecules, the panel of analytical evaluators plays a fundamental role, both in sensory analysis and in GC-O, and requires a selection process and training prior to the development of the analysis. The biographical study carried out on the applications of the GC-O highlights the most important aspects of odorant extraction techniques, the olfactometric techniques used and the number of panelists used, among other aspects.

Due to the importance of the authentication of the botanical and geographical origin of honey, this document is focused on the use of phenols as potential chemical markers in an attempt to distinguish and characterize one of the non-floral honey types, oak (Quercus sp.) honey, from other honeydew honeys produced in other regions. The development and validation of ultra-high-performance liquid chromatography with mass spectrometry detection enables the identification of 23 phenolic compounds in 58 Spanish oak honeydew honey samples. The proposed compounds, above all salicylic acid (mean = 24.31 mg 100 g−1), but also p-coumaric acid, p-hydroxybenzoic acid, syringic acid, naringenin, and galangin could further contribute as a helpful tool in the quality control of this non-floral honey, and therefore distinguish it from European honeydew honey and those from other regions. Furthermore, many positive correlations between phenolic compounds, CIELAB color parameters, and antioxidant activity are established. This research presents a complete phenolic composition and the largest sampling of one of the most appreciated honeydew honey varieties. This is also one of the singular studies that have successfully linked individual phenolic acids and flavonoids with physicochemical parameters within the same unifloral honey.

El mapa conceptual es una herramienta organizadora del conocimiento que promueve el aprendizaje y el trabajo en equipo, así como el incremento de la motivación e interés del estudiante. Se ha diseñado un mapa conceptual para facilitar el aprendizaje de la dispensación de antibióticos pediátricos en la Oficina de Farmacia utilizando la app Wooclap . Se han definido cuatro bloques principales: conocimiento de datos necesarios en una prescripción, cálculo de dosis pediátricas, reconstitución y conservación del medicamento, y además se ha elaborado una encuesta de satisfacción que permitirá evaluar la adecuación de esta actividad en el proceso de aprendizaje de los alumnos. Esta metodología docente se incorporará entre las actividades que se desarrollan en el aula práctica de la asignatura de Prácticas Tuteladas., The concept map is a knowledge organising tool that promotes learning and teamwork, as well as increasing student motivation and interest. A concept map has been designed to facilitate learning about the dispensing of paediatric antibiotics at the Pharmacy Office using the Wooclap app. Four main blocks have been defined: knowledge of the necessary data in a prescription, calculation of paediatric doses, reconstitution and conservation, of the medication, and a satisfaction survey has also been developed to evaluate the suitability of this activity in the students' learning process. This teaching methodology will be incorporated into the activities carried out in the practical classroom of the Training Placements subject.

In this preliminary study, the effect of regulated deficit irrigation (RDI) on the commercial quality (size, weight, soluble solids, firmness and colour), content of carotenoids, phenolics and sugars of black tomato (Solanum lycopersicum L.) ʽSunchocolaʼ was studied. Two water irrigation treatments were applied: regulated deficit irrigation (RDI) and control with 82,7 and 398 mm of water supplied, respectively. Tomato of the first cluster harvested at three stages of maturity were studied. The size and weight of the tomato did not present significant differences regarding the RDI and maturity. In both groups the concentration of carotenoids and phenolics increased with the degree of maturity (on average 57 % and 8 % respectively). On the other hand, in most cases, the content of carotenoids, phenolics and sugars showed significant differences between irrigation treatments (p < 0.1). In conclusion, with the application of the RDI, it was possible to maintain the size and weight and increase the carotenoid levels of the fruits.

Our aim in this study was to outline phenolic and color characteristic that characterize the labeled unifloral resin spurge (Euphorbia resinifera) honey. With respect to phenolic composition, 17 phenolic compounds have been analyzed in the 29 honey samples. The proposed markers (syringic acid, ethyl gallate, m-coumaric acid and naringenin) might help to the enhancement of this honey type and thus, guarantee its commercial value. The color characterization by diffuse reflectance spectrophotometry revealed typical values of light amber honey (lightness ranged from 36 to 70 units, and chroma from 18 to 30 units). On the other hand, many correlations between the color attributes and phenolic acids, total phenolic compounds, caffeic acid, p- and m-coumaric acids and hesperidin have been demonstrated, also, correlation between phenols, color parameters and percentage of pollen of E. resinifera has been found. This study is one of the rare researches which have correlated the CIELAB color parameters with the individual phenolic acids and flavonoid compounds within the same unifloral honey.

El fenómeno de la luminiscencia se produce cuando un átomo o molécula, previamente excitados, regresan a su estado fundamental, emitiendo luz. Las bases que explican este proceso quedaron establecidas por Jablonski en 1930, quien elaboró un diagrama donde detalla la emisión de luz por parte de un compuesto preexcitado. Las reacciones de luminiscencia pueden clasificarse en función del agente causal de las mismas. Así, la quimioluminiscencia estará originada por una reacción química que genera un producto excitado. Este producto liberará la energía sobrante en forma de emisión de luz al pasar a su estado fundamental, en el que es más estable. Los avances en el área de la investigación han permitido elaborar nuevos métodos de detección basados en reacciones quimioluminiscentes, que aportan beneficios en múltiples campos. La elevada sensibilidad, unida al bajo costo del proceso y a la rapidez en la obtención de resultados, hacen de estas técnicas un recurso muy valioso. El luminol y los ésteres de acridinio son dos compuestos utilizados en multitud de reacciones quimioluminiscentes con amplias posibilidades de uso, incluido los ensayos de inmunoanálisis por quimioluminiscencia, que aportan grandes ventajas para la salud de la población. Así, a lo largo de esta revisión bibliográfica se expondrá el valor del luminol para la detección de manchas de sangre, con aplicación en medicina forense y técnicas de esterilización y prevención de infecciones nosocomiales; para garantizar la calidad y el buen estado de aguas de consumo y de alimentos; y como método de detección del cáncer. De igual forma, se mostrará la relevancia de los ésteres de acridinio en la detección de enfermedades como el COVID, el Alzheimer o la toxoplasmosis.

Flowers have been used for centuries in decoration and traditional medicine, and as components of dishes. In this study, carotenoids and phenolics from 125 flowers were determined by liquid chromatography (RRLC and UHPLC). After comparing four different extractants, the carotenoids were extracted with acetone: methanol (2:1), which led to a recovery of 83%. The phenolic compounds were extracted with 0.1% acidified methanol. The petals of the edible flowers Renealmia alpinia and Lantana camara showed the highest values of theoretical vitamin A activity expressed as retinol activity equivalents (RAE), i.e., 19.1 and 4.1 RAE/g fresh weight, respectively. The sample with the highest total phenolic contents was Punica granatum orange (146.7 mg/g dry weight). It was concluded that in most cases, flowers with high carotenoid contents did not contain high phenolic content and vice versa. The results of this study can help to develop innovative concepts and products for the industry.

La luminiscencia es un proceso que afecta tanto a átomos como a moléculas, donde se produce emisión de energía no térmica en forma de luz requiriendo una preexcitación previa del compuesto. Para explicar este fenómeno se utiliza el diagrama de Jabłoński, donde se definen las dos formas de emisión de luminiscencia y sus características: la fluorescencia y la fosforescencia, que se diferencian principalmente en que la pérdida de exceso de energía ocurre sin cambio de multiplicidad de spin en la fluorescencia mientras que en la fosforescencia si se produce cambio, provocando que el tiempo de emisión de luminiscencia en fosforescencia sea más prolongado. Las principales fuentes de excitación que producen luminiscencia son la quimioluminiscencia, donde se produce luminiscencia por reacciones químicas, y la bioluminiscencia, donde se produce por reacciones catalizadas por enzimas en organismos vivos. Para la medida de esta luminiscencia en el laboratorio se utilizan tres instrumentos, el espectrofluorímetro, el fluorómetro y el fosforímetro. El conocimiento de la utilidad de la luminiscencia en la química analítica ha llevado a la comunidad científica al desarrollo y estudio de moléculas con esta característica. En esta revisión se han tratado de recoger los puntos más importantes sobre las principales aplicaciones analíticas de cuatro moléculas, que han sido elegidas por su utilidad en el campo sanitario y medioambiental, así como en el análisis químico. Las moléculas estudiadas son el luminol, la quinina, la fluoresceína y la proteína verde fluorescente (GFP). Además, cabe destacar que la fluoresceína también tiene numerosas aplicaciones en el campo de la óptica.

Non-centrifugal cane sugar (NCS) samples obtained by traditional moulding and granulation, and also via a novel spray-drying powdering process without additives, were assessed to characterise their sugar and phenolic profiles, flavonoid content, as well as colour parameters. As expected, sucrose was the predominant sugar (91.9–95.5%), followed by glucose (2.9–4.6%), and fructose (1.6–3.7%). Total phenolic content was between 0.4 and 0.6% and total flavonoid content into the range of 0.2–0.4%. Six phenolic acids were found in all NCS samples: protocatechuic acid (0.36–0.94 µg/100 g), vanillic acid (0.70–1.45 µg/100 g), chlorogenic acid (2.08–3.82 µg/100 g), syringic acid (1.08–2.80 µg/100 g), p-coumaric acid (0.69–1.35 µg/100 g), and ferulic acid (0.50–0.95 µg/100 g). The thermal treatment under high temperatures required in the production of granulated products was related with darker colours and changes in phenol and flavonoid contents. In contrast, spray drying generates clearer products, but with slightly less phenol and flavonoid contents.

La percepción del color es una capacidad adaptativa y de supervivencia de los seres vivos. Conocer cómo se produce el color y los mecanismos de su percepción, permite seleccionar o diseñar diferentes agentes generadores para muchas aplicaciones cotidianas y estrategias médicas de diagnóstico e intervención en caso de anomalías. En este trabajo de revisión se han revisado los conceptos fundamentales del color, los mecanismos fisiológicos y los compuestos químicos que generan color. Metodología. En una etapa preliminar la exploración de información se realizó empleando base de datos (Pubmed, Google académico, Sciencedirect y Dialnet) con los términos de búsqueda “color” y “química del color”, y se limitó al título o resumen, en el período de 2015 a 2020. Resultados y discusión. De la revisión se puede extraer que las sustancias en sí mismas no poseen color, sino que reflejan luz que, una vez captada por fotorreceptores biológicos, es transducida en color y que los objetos pueden estar compuestos de pigmentos o colorantes, de forma natural o por incorporación deliberada, estos son agentes muy eficaces reflejando luz visible y por lo tanto generando color. Conclusiones. Los pigmentos y colorantes pueden obtenerse de fuentes biológicas o sintéticamente.

Extraction solvent is a very important factor in the recovery of antioxidants from natural matrices. In this study, the effect of three solvents (ethanol, ethanol/water and water) on the phenolic composition, antioxidant and anti-cholinesterase activities and electrochemical behaviour of four winemaking byproducts (seeds, skins, stems, and pomace) was evaluated. Phenolic composition was determined by the Folin–Ciocalteu method and ultra-high-performance liquid chromatography (UHPLC), antioxidant activity by the capacity to scavenge 2,2-diphenyl-1-picrylhydrazyl and hydroxyl radicals, anti-cholinesterase activity by the Ellman’s method, and electrochemical behaviour by cyclic voltammetry. Eight phenolic compounds were quantified with higher content in water/ethanol extracts (e.g., epicatechin in pomace: 17 mg/100 g vs. 7 and 6 mg/100 g in ethanol and water extracts, respectively), although there were some exceptions (e.g., gallic acid in seeds was most abundant in water extracts). Moreover, the highest total phenolic content (TPC) and antioxidant activity were found in ethanol/water extracts (between 2 and 30-fold the values of the other extracts). Overall, the most active extracts in inhibiting both acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) enzymes were ethanol/water and ethanol extracts from seeds (between 31.11 and 53.90%). The electrochemical behaviour allowed for differentiating the extracts depending on the solvent and the byproduct. Our findings indicate that winemaking byproducts represent a source of phenolic compounds with antioxidant and anti-cholinesterase activities and suggest that cyclic voltammetry is a promising technique to evaluate the phenolic extraction process from these byproducts.

The current university environment is characterised by the implementation of an education system focused on competence-based learning. The present study has concentrated on the subject Applied Analytical Chemistry of the Pharmacy Degree and has made it possible to clearly establish the specific competences of the subject, based on levels of acquisition, as well as to design a system of assessment, based on the use of rubrics, which provides the corresponding equivalences in the grading system currently used in the university. This new form of assessment allows the teacher to know where there are gaps in student learning, and this information can be subsequently used to prioritize the training of those skills. The implementation of these rubrics has made it possible to obtain relevant information related to the students’ acquisition of competences., El entorno universitario actual se caracteriza por la implementación de un sistema educativo centrado en el aprendizaje basado en competencias. Este trabajo se centra en la asignatura de Química Analítica Aplicada del Grado en Farmacia y trata de establecer claramente las competencias específicas de la asignatura, en función de los niveles de adquisición, así como diseñar un sistema de evaluación, basado en el uso de rúbricas, proporcionando las equivalencias correspondientes en el sistema de calificación actualmente utilizado en la Universidad. Esta nueva forma de evaluación permite al docente saber dónde hay vacíos en el aprendizaje de los estudiantes, de modo que esta información puede usarse posteriormente para priorizar el entrenamiento de esas habilidades. La implementación de estas rúbricas ha permitido obtener información relevante relacionada con la adquisición de competencias de los estudiantes.

The quality of 27 Moroccan Spurge (Euphorbia) honey samples was assessed. Eight physicochemical parameters and mineral composition were analysed and the CIELAB colour parameters (L∗, a∗, b∗, Cab ∗ and hab) were determined. Results show no significant differences between the two Euphorbia honey types (Euphorbia officinarum subsp. echinus and Euphorbia regis-jubae honeys) regarding the physicochemical parameters. Sodium and magnesium show average values that can help to differentiate between E. officinarum subsp. echinus and E. regis-jubae honeys. Potassium was quantitatively the most important mineral (66% of the total minerals quantified), while sodium and calcium were present in moderate amounts (20% and 11% of the minerals, respectively). The colour parameters also have shown significant differences between E. officinarum subsp. echinus and E. regis-jubae honeys. Considering the total information from physicochemical, mineral and colour data, Principal Component Analysis (PCA) and Stepwise Discriminant Analysis (SDA) were carried out to distinguish between the two Euphorbia honey types. PCA showed that the cumulative variance was approximately 56%. The results of SDA showed that parameters with a higher discriminant power were Na, Mg, L∗, Cab ∗ and hab, and almost 100% of the samples were properly classified in their corresponding group, except for one sample.

Cooperage byproducts are an important source of phenolic compounds that could be used for wine technology applications. The effects of the addition of two types of oak wood shavings (American, AOW, and Ukrainian, UOW) on the antioxidant activity and color of red wine anthocyanins, in a wine model solution, were evaluated by spectrophotometric and colorimetric analyses. Phenolic compounds from shavings, mainly ellagitannins, were determined by ultra-high-performance liquid chromatography/mass spectrometry (UHPLC/MS). Antioxidant and copigmentation effects varied depending on the type of shavings (AOW and UOW) and the phenolic concentration (100, 400, and 500 mg/L). Phenolic compounds from shavings improved the color characteristics (darker and more bluish color) and the copigmentation effect of red wine anthocyanins, being UOW a better source of copigments than AOW shavings. The best antioxidant activity was found for the 400 and 500 mg/L model solutions for both types of shavings. Results show a winemaking technological application based on the repurposing of cooperage byproducts, which could improve color and antioxidant characteristics of red wines.

The aim of this study was to assess commercial quality parameters, sugars, phenolics, carotenoids and plastid in diverse and little studied tomato varieties to gain insight into their commercial and functional quality and reveal possible noticeable differences. Five cherry tomato varieties and six common (i.e., non-cherry) tomatoes were evaluated. The highest levels of lycopene were detected in ‘Tigerella’ and ‘Byelsa’ and those of phytoene in ‘Orangeʾ those of phenolics in ‘Green Zebra’ all of them common tomatoes. The levels of sugars in both groups of tomatoes were comparable. Interesting differences in plastid carotenoid-accumulating sub-structures as a function of the carotenoid profile were observed. Given the importance of chromoplasts in the deposition of carotenoids in plants and their release during digestion, this information can be valuable in investigations on the regulation of the biosynthesis and the bioavailability of tomato carotenoids.

This work analyzed the use of electrocoagulation as substitute for sugarcane clarification process using sulfitation. It was evaluated technological parameters (Icumsa color and turbidity), phenolic compounds content and CIELAB color parameters. Four kinetics of reduction color from sugarcane juice were carried out. The essays were divided according to the voltage applied: 35, 45, 55 and 65 V (also based on previous tests). Higher voltage treatments achieved greater reduction of Icumsa color, turbidity and total phenolic compounds. However, none of treatments impacted simple phenolic content analyzed in this work. Tristimulus analysis presented some pattern that went beyond technological analysis, including that 65 V essay changed the pigmentation of sugarcane juice and had an early stabilization on chroma. This kind of results could be useful for industry, once they could correlate quality with different color parameters and finally improve the clarification in general with finer settings of technique according to different situations.

Anthocyanins are phenolic compounds with important technological applications due to its bioactive and color properties. In this study, pomaces from four red berries (blueberries, red raspberries, red currants and blackberries) have been analyzed as sources of anthocyanins. Anthocyanins were determined by high-performance liquid chromatography/mass spectrometry, total phenolic content (TPC) by Folin–Ciocalteu method, antioxidant activity by ABTS assay, and color by tristimulus colorimetry. A total of 15 anthocyanins were identified and quantified in the different pomaces from red berries. Pomaces exhibited different qualitative and quantitative anthocyanin profile and antioxidant activity, depending on type of red berry. The highest amounts of anthocyanins were found in blueberries (1188 mg/100 g); however, red currant pomaces exhibited the highest TPC (3447 mg/100 g) and AA (61 mmol/100 g). Color of extracts was different depending on individual and total content of anthocyanins. Results indicate that these berry pomaces are a natural source of antioxidants and pigments, and they may be useful for industrial purposes. Therefore, the exploitation of these pomaces, such as possible byproducts for their reuse in the food, cosmetics, and drug industries, could be of great interest, considering either the whole pomaces or its individual components.

The emergent market for honeydew honeys in Europe prompt to increasing requirements of consumers and honey industry for the characterisation of this type of honey. The aim of this study was to characterise 59 samples of Spanish oak honeydew honeys. Physicochemical properties showed values within the limits established by the legislation and typical for honeydew honeys. Honeys were differentiated into two groups according to the hue (hab) and all were classified as dark honeys (L* < 55). A total of 14 minerals were determined, with K, P, Mg, and Ca being the most abundant. The development and validation of an HPLC method allowed the determination of the contents of two monosaccharides, five disaccharides, and two trisaccharides. Total phenolic and flavonoid contents showed mean values of 130.2 mg/100 g and 11.3 mg/100 g of honey, respectively. Honeydew honeys showed ability to scavenge free radicals and to inhibit lipid peroxidation, which is very interesting, because, as far as we know, there are no previous studies for this type of honey. Results showed that all honeydew honeys are a source of chemical compounds with nutritional and antioxidant properties that could be of interest for consumers and food industry.

La miel es la sustancia natural dulce producida por la abeja Apis mellifera a partir del néctar de plantas o de secreciones de partes vivas de plantas o de excreciones de insectos chupadores presentes en las partes vivas de plantas, que las abejas recolectan, transforman combinándolas con sustancias específicas propias, depositan, deshidratan, almacenan y dejan en colmenas para que madure. La miel de mielada es aquella que procede en su mayor parte de excreciones de insectos chupadores de plantas (hemípteros) presentes en las partes vivas de las plantas o de secreciones de las partes vivas de las plantas. Las principales diferencias entre la miel de néctar y de mielada son en la de conductividad eléctrica, el pH y la acidez. A lo largo del tiempo, la miel ha sido utilizada no solamente por sus propiedades nutritivas sino también por sus propiedades beneficiosas para la salud como son su acción antibacteriana, antifúngica, antiinflamatoria, antiséptica y cicatrizante Los compuestos fenólicos además de contribuir a las características sensoriales de la miel participan junto a otro grupo de constituyentes minoritarios en la actividad antioxidante. La determinación de los compuestos fenólicos se lleva a cabo mediante técnicas de separación, primero se realiza una extracción en fase sólida seguida de una extracción líquido-líquido y posteriormente el extracto se analiza en un cromatógrafo de líquidos. El proceso analítico puede entenderse como un proceso de tres etapas distintas que se construyen en relación con la etapa central de medida. Estas etapas son: toma y preparación de la muestra, medida de la señal analítica y toma de datos y el tratamiento de datos y la expresión de resultados. Mediante la calibración metodológica realizamos el tratamiento de datos estableciendo una relación entre la respuesta de un instrumento obtenida del cromatógrafo y la concentración analítica. En este estudio se han identificado distintos ácidos hidroxibenzoicos como son: el ácido gálic

La valoración fotométrica es una técnica analítica basada en las volumetrías y en la espectrofotometría, por lo que para definirla, primero se ha hecho un revision de las dos técnicas analíticas. La valoración fotométrica emplea la absorción de la luz para seguir el proceso de una reacción química. Durante la valoración se mide continuamente la absorbancia de la disolución al ir adicionando reactivo valorante. Existen dos tipos de valoraciones fotométricas: directas e indirectas. En las valoraciones directas, una de la especies participantes en la reacción absorben a la longitud de onda que se mide y en las indirectas, es necesaria la adicción de un indicador, que es el que va a absorber la luz. Estas valoraciones fotométricas se usan para determinar el punto de equivalencia en una valoración. Se determina mediante las curvas de valoración, las cuales son lineales y la intersección entre las dos rectas permitirá calcular el volumen de valorante en el punto de equivalencia. En esta revisión se señalan los diferentes tipos de curvas de valoración que pueden obtenerse dependiendo de la especie química que absorba en la longitud de onda de medida. Además las valoraciones fotometricas tienen ciertas ventajas frente a otro tipo de técnicas y sus aplicaciones en diferentes campos es sencilla y rápida. En esta revisión, se han considerado aplicaciones de las valoraciones fotométricas en diferentes ámbitos que conciernen al ámbito farmacéutico como la determinación de un surfactante catiónico tipo diamina, paracetamol en medicamentos, calcio en suero sanguíneo, cargas en la superficie de las células, fenotiazinas con sulfato cérico, carrageninas y hierro en vino blanco; y también al ámbito medioambiental como es la determinación de sulfatos en agua de mar.

The individual preferences of 100 consumers between 20 and 30 years old for the color of 16 milk–fruit juice beverages (MFJB) were investigated by preference mapping technique. Consumers were asked to evaluate, just by looking at the samples, how much they liked them (from “Extremely dislike” to “Extremely like”). The color of the samples was analyzed by two different instrumental techniques. Results obtained from the instrumental color measurement showed the wide diversity in hues of the beverages available in the market, and correlations between techniques proved that both of them were appropriate to analyze color. Results showed that participants preferred samples with orangish appearance instead of those with a whiter look. Anyway, punctuations given by the consumers suggest that generally, color of these products is not highly evaluated by consumers, as the best mean punctuation was 6.6.

The purpose of this study was to assess the relationship between the effect of regulated deficit irrigation, cluster, developmental stages and two seasons (autumn 2015 and spring 2016) on the commercial and functional quality (carotenoids and plenolics levels) in ‘Lazarino’ and 'summerbrix’ tomatoes. Autumn had a positive effect on the commercial quality, with larger fruits (22% in 'summerbrix’; 26% in ‘Lazarino’) and higher soluble solids (16% in 'summerbrix’; 12% in ‘Lazarino’). Total carotenoids did not change significantly with irrigation and variety while total phenolics did with the cluster and season. In most cases, the main amounts of carotenoids and phenolic were found in the higher cluster and carotenoids in ripe fruit. Thus, irrigation of such varieties could be reduced drastically (ca. 80%) without affecting considerably the overall quality of their fruits (changes not greater than 30%).

The effect of in vitro gastrointestinal digestion on phenolic composition and antioxidant activity of different white winemaking byproducts extracts (grape pomace and its parts: seeds, skins and stems) was evaluated. Fourteen individual phenolic compounds were evaluated by UHPLC. The antioxidant activity was measured by DPPH and ORAC assays. Differences on phenolic profile and antioxidant activity were observed depending on the digestion phase, the type of byproduct, the phenolic group and the antioxidant activity method. In general, digestion had a reducing effect on TPC and antioxidant activity; however, ORAC values of seed and stem extracts increased after digestion and some recovery indexes of the phenolic groups were very high. Results indicate that extracts from white winemaking byproducts are a reliable source of bioaccessible antioxidant compounds, which could be used as functional food ingredients.

Wine contains polyphenols that are responsible for its quality. Moreover, phenolic compounds have antioxidant properties and benefits on human health. Cyclic voltammetry (CV) was the first electrochemical method used for polyphenols characterization and determination of polyphenols content in wine products. Electrochemical behaviour of standard solutions of phenolic compounds has been investigated and evaluated the importance of the phenolic concentration and pH. The electrochemical parameters extracted from the voltammograms have been correlated with the antioxidant potential in wine products. In addition, CV allowed establishing differences in the antioxidant activity of wines with different addition of grape seeds. In winemaking by-products, different Ipa and Q500 values were found depending on the state of maturation of the grape pomace. On the other hand, the total flavonoids and phenolic acids contents were significantly correlated to the electrochemical parameters. Differences for the electrochemical parameters were found between by-products, being pomace and seeds which presented the greatest values of Q500. Simple regression analyses showed that voltammetric parameters are correlated to their values of lipid peroxidation inhibition by thiobarbituric acid reactive substances method. Our results open the possibility of CV as a promising technique to estimate the global antioxidant potential of wine products rich in phenolic compounds.

This study aims to evaluate the effects of regulated deficit irrigation (RDI) and of cluster position (CI: first and second cluster; CII: third and fourth cluster; CIII: fifth and sixth cluster) on fruit quality parameters, carotenoids and phenolics in tomatoes. Three common (‘Tigerella’, ‘Palamós’ and ‘Byelsa’) and two cherry varieties (‘Lazarino’ and ‘Summerbrix’) were studied. The results showed that the regulated deficit irrigation with reduction of 40 and 50% in the leaf water potential in common and cherry tomatoes did not affect greatly the organoleptic quality of common tomatoes and ʽSummerbrixʼ, while cherry varieties were significantly affected with the cluster position. In most case, significant changes in the levels of carotenoids were observed depending on the treatment and the cluster position in all varieties. Significant changes with the treatment and no change with the cluster position were observed in phenolic compounds. Thus, in general, increased total carotenoid levels and reduced the content of phenolic compounds were observed. Considering the significance of changes in the levels of these groups of compounds it was concluded that ʽLazarinoʼ was more susceptible to water deficit, whereas ʽSummerbrixʼ and ʽPalamósʼ were more resistant. On the other hand, the organoleptic and functional quality changed with the variety.

In this study, foam mat drying was applied to Tommy Atkins mango. Using a multifactorial design, the effect of soy lecithin (L) and carboxymethylcellulose (CMC) used as foam stabilizers (0–1.50 g/100 g), as well as temperature (T) (53–87 °C), on phenolic content and antioxidant capacity of mango were eval- uated. Mango pulp contains antioxidant, such as mangiferin, that can be utilized in foods to enhance their functional properties. Our results indicated that L and T had negative effects (p < 0.05) on the phenolic content and antioxidant capacity, whereas CMC had a positive effect (p < 0.05). Increasing the total amount of phenolic compounds present in dried mango contributed to the higher antioxidant capacity after the drying process. This study concluded that a drying T of 80 °C, and a concentration of 0.30 g/100 g of CMC and L are optimal for increased retention of phenolic compounds and antioxidant capacity.

Las valoraciones son ampliamente utilizadas en química analítica para la determinación de ácidos, bases, oxidante, reductores, iones metálicos y muchas otras especies. Se basan en una reacción entre el analito y un reactivo patrón, conocido como valorante, esta reacción tiene una estequiometria conocida y reproducible. En una valoración se determina el volumen del valorante necesario para reaccionar de manera completa con el analito y se emplea dicho volumen para conocer la cantidad de analito. En todas las valoraciones, el punto de equivalencia química, denominado experimentalmente punto final, se detecta por el cambio de color de un indicador o un cambio en la respuesta del instrumento. La diferencia entre el punto final y el punto de equivalencia es el error de valoración. La validez del resultado de los métodos volumétricos depende de que se sepa la concentración de la disolución valorante. Esta concentración se conoce si se prepara disolviendo una cantidad conocida de reactivo puro, llamado patrón primario. En el caso de no disponer de patrón primario, se prepara la disolución con una concentración aproximada a la deseada y se valora con un patrón primario. Este procedimiento, donde se determina la concentración del valorante destinado a un análisis, se conoce como estandarización y al valorante disolución estándar. Los métodos volumétricos se clasifican atendiendo al procedimiento en valoración directa, por retroceso o indirecta, y atendiendo a la forma de realizarse en valoración manual o clásica y automatizada. Para realizar una valoración automatizada se necesitan accesorios adecuados que puedan llevar a cabo automáticamente la adición de la disolución valorada y la determinación del punto final de una volumetría. Las valoraciones automáticas son más precisas y tienen mayor rendimiento en comparación con la valoración manual. Se han revisado valoraciones aplicadas en el ámbito de la farmacia, como la determinación de ácido fosfórico, nitrógeno, ácido ascórb

Grape pomace is composed of seeds, skins and stems that are an important source of phenolic substances, which have antioxidant properties and potential benefits to human health. Cyclic voltammetry (CV) has been used to measure the total antioxidant potential of different winemaking by-products. The electrochemical behavior of pomace, seeds, skins and stems was measured by CV and lipid peroxidation inhibition by thiobarbituric acid reactive substances (TBARS) method. Differences for the electrochemical parameter were found between the by-products, pomace and seeds, which presented the greatest voltammetric peak area. Furthermore, the by-products induced inhibition of lipid peroxidation in rat liver homogenates. Pomace and seeds showed higher capacity to inhibit lipid peroxidation than stems and skins, which could be because these by-products are richer in flavanols. Simple regression analyses showed that voltammetric parameters are highly correlated to the values obtained for lipid peroxidation inhibition. CV is a promising technique to estimate the total antioxidant potential of phenolic extract from winemaking by-products.

Los consumidores cada vez valoran más el consumo de mieles de mielada debido a su valor nutricional y sus propiedades medicinales, que son diferentes a las de las mieles de flores. La composición de la mielada es diferente a la del néctar; de manera general contiene menos glucosa y fructosa además, algunos parámetros físicoquímicos como pH, acidez, cenizas, conductividad eléctrica y minerales pueden ser usados para diferenciar las mieles de néctar de las de mielada, o de manera general pueden indicar la presencia de la mielada en la miel. Por otro lado, los valores de estos parámetros pueden variar, dependiendo de factores como el origen geográfico, botánico y condiciones climáticas, lo que conlleva a la existencia de distintos tipos de mieles de mielada dependiendo también de la fuente de los insectos chupadores de las plantas y de las plantas huésped. Se han analizado 59 muestras de mieles de mielada españolas desde el punto de vista fisicoquímico y se ha determinado la conductividad eléctrica, humedad y pH. Las mieles presentaron un valor medio de 999 μS/cm de conductividad eléctrica, 16,5 % de humedad y 4,74 de pH. La calidad de la miel está relacionada con su composición. La humedad y el pH son de gran importancia en las mieles de mielada ya que intervienen en la textura, estabilidad y viabilidad de la miel, y por otra parte, la conductividad eléctrica se relaciona con el contenido de sales minerales, ácidos orgánicos y proteínas, Consumers are increasingly evaluating more consumption honeydew because of its nutritional value and its medicinal properties, which are different from the honey of flowers. The composition of the honeydew is different from the nectar; generally contains less glucose and fructose and in addition, some physicochemical parameters such as pH, acidity, ash, electrical conductivity and minerals can be used to differentiate between honeys nectar and honeydew honey, or generally these parameters can indicate the presence of the honeydew in honey. On the other hand, the values of these parameters may vary, depending on factors such as geographical and botanical origin, and climatic conditions, which leads to the existence of different types of honeydew honeys also depending on the source of plant-sucking insects and host plants. Fifty-nine samples of Spanish honeydew honeys were analyzed from the point of view physiochemical and electrical conductivity, moisture and pH were determined. Honeys had an average value 999 μS/cm in electrical conductivity, 16.5% in moisture and a pH 4.74. The quality of honey is related to its composition. Moisture and pH are of great importance in honeydew honeys because they are involved in the texture, stability and viability of honey and, on the other hand, the electrical conductivity is related to the content of mineral salts, organic acids and proteins

Background and Aims:Winemaking generates a large quantity of grape marc that causes environmental and economic problems, which could be minimised by exploiting and adding value to these by-products. Marc is composed of seeds, skins and stems that are an important source of phenolic substances, which have antioxidant properties and potential benefits to human health. It is necessary to develop novel methods for assessing the composition of marc because conventional analyses are destructive and require lengthy preparation procedures and chemical reagents. Methods and Results: Near-infrared hyperspectral imaging has been used for evaluating 27 individual phenolic substances in the components of grape marc after freeze-drying, the only sample preparation step. By applying partial least squares regression to the spectral data, values of R2 up to 0.98 were obtained even for estimating some minor compounds. Conclusions: This methodology arises as an attractive alternative to analyse the phenolic composition of grape marc because of its speed and simplicity. Significance of the Study: The use of this technique will allow wine producers to quickly determine the phenolic composition and decide the destination of this by-product

The influence of adding seeds from grape pomace during Syrah wine fermentation in a warm climate has been studied. Seeds of Pedro Ximenez variety were rich in phenolic compounds, mainly flavonoids such as catechin and procyanidins. Changes in total phenolic content (TPC), total flavonoid content (TFC), and antioxidant activity of red wines were observed. These changes depended on the vinification stage and the amount of seeds (SW: 450 g or DW: 900 g seeds/150 kg grapes) applied. In general, antioxidant activity was greater when a simple dose (SW) was considered. Results indicate that seeds rich in flavonoids could be used as wine additives, which could improve the antioxidant potential of red wines in a warm climate.

Los compuestos volátiles del aceite de oliva virgen (VOO) son los responsables de su aroma, algunos de ellos originan las notas sensoriales frutadas y verdes propias de los VOO de calidad, como es el caso de los compuestos de 5 y 6 átomos de carbono, y otros originan defectos sensoriales, como la rancidez, provocando el rechazo por parte del consumidor. La identificación y cuantificación de los compuestos volátiles permite conocer la vida útil del VOO como indicador del proceso de oxidación y de la aparición de defectos sensoriales. Se ha aplicado un método analítico, basado en espacio de cabeza dinámico-cromatografía de gases, al estudio de la vida útil del VOO, almacenado durante 6 meses, observándose desde el tercer mes un aumento significativo de los compuestos característicos de la rancidez, que actúan como marcadores volátiles, tales como aldehídos insaturados, saturados y ácidos. Por otro lado, se han adicionado plantas aromáticas al aceite para evaluar la vida útil del VOO, observándose la modificación de sus propiedades sensoriales y un retraso del proceso oxidativo. Las plantas empleadas en este estudio han sido romero y albahaca. Se he realizado la identificación de su perfil de volátiles siendo de destacar la presencia de hidrocarburos y compuestos terpénicos. A lo largo del almacenamiento se produce una transferencia de compuestos terpénicos al aceite desde el primer mes de almacenamiento, lo que se ha confirmado mediante análisis descriptivo cuantitativo. El análisis sensorial demuestra la presencia de atributos sensoriales propios de la albahaca y el romero en las muestras aderezadas y un aumento del atributo rancio en el aceite de oliva virgen.

La química analítica tiene como finalidad el estudio de la composición química de una muestra, mediante métodos de laboratorio analíticos. En cualquier laboratorio de química analítica, el objetivo principal es obtener resultados fiables y consistentes, es decir, resultados de calidad. Para ello es fundamental constatar que el método que se va a usar se adecua al problema analítico que se presenta. Esto se consigue mediante la validación del método analítico. La validación se realiza mediante una serie de pruebas o procesos que permiten asegurar que se obtendrán resultados de calidad. Mediante estos procedimientos de validación, se obtendrán unas propiedades analíticas del método que indicaran si el método es válido o no para la finalidad con la que se utiliza. La determinación de dichas propiedades o parámetros se consigue entre otros, con el procedimiento de calibración del método de análisis. Dentro de química analítica existen principalmente dos tipos de métodos, los instrumentales y los no instrumentales como los volumétricos. Para cualquiera que sea el método se requiere una calibración del equipo a utilizar, que es el paso inicial en cualquier proceso analítico. Posteriormente los métodos instrumentales requieren además de una calibración metodológica, que asegura que el procedimiento es válido para el problema concreto que se presenta y el analito que se estudia. Se puede calibrar por tres técnicas, siendo la más simple y rápida la calibración simple o por estándar externo, pero también la que requiere de menos problemas relacionados con el método. La calibración por adición estándar es útil para compensar el efecto que pueden producir otras sustancias a la señal que mide el equipo. Por último, se puede utilizar el método del patrón interno, para aquellos procesos analíticos en los que se produzcan muchas variaciones entre cada operación y eso cause resultados analíticos diferentes. En este trabajo se describen los principales conceptos relacionados con la c

Roselle is a plant that accumulates anthocyanins significantly, hence its importance as food coloring and as a source of antioxidant compounds for human health. This study was aimed to determine phenolic composition and antioxidant capacity of methanolic extracts, and beverages obtained from native roselle cultivars in Mexico (Negra, Sudan, Rosa and Blanca) with different degrees of pigmentation, and to establish the color-composition relationship. Chromatographic methods were used to determine phenolic compounds: flavanols, flavonols, benzoic, hibiscus and phenolic acids as well as two main anthocyanins (cyanidin 3-sambubioside and delphinidin 3-sambubioside). The antioxidant capacity was evaluated by ABTS and FRAP assays. Tristimulus colorimetry showed to be a useful technique to determine the color-composition relationship, leading to equations that allowed to predict anthocyanin content of roselle (R > 0.84). Also, a stepwise linear discriminant analysis (SLDA) was developed in order to classify roselle cultivars. The obtained mathematical model could be an important tool to be used in colorimetric characterization of functional compounds used in food processing.

The antiproliferative effects of a purified white grape pomace extract (PWGPE), as well as of some phenolic standards on colon cancer cells were examined. The phenolic composition of the PWGPE was determined by rapid resolution liquid chromatography/mass spectrometry (RRLC/MS). The PWGPE had 92.6, 43.3 and 6.01 mg/g of flavanols, flavonols and phenolic acids, respectively and, along with pure catechin, epicatechin, quercetin and gallic acid, they were all found capable of inhibiting cellular proliferation. PWGPE (100 lg/ml) inhibited the proliferation of cells by 52.1% at 48 h, whilst catechin, epicatechin, quercetin and gallic acid (60 lg/ml) inhibited growth by 65.2%, 62.2%, 81.0% and 71.0%, respectively, at 72 h. The PWGPE is an interesting source of phenolic compounds with antiproliferative properties, that could be of interest in the food and pharmaceutical industries.