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Este trabajo muestra los desafíos que ha tenido el profesorado, como consecuencia de la pandemia del COVID 19, que ha azotado a la población mundial. Tiene un enfoque mixto, prevaleciendo a lo largo del estudio la triangulación de datos cuantitativos y cualitativos. El Índice de Excelencia de la Gestión Directiva (IEGD) se calculó utilizando los indicadores del sistema de mejora de la calidad de la Federación Internacional de Fe y Alegría; de igual manera, la valoración de 35 prácticas innovadoras con enfoque de género y uso de las Tecnologías de la Información y la Comunicación (TIC), utilizando criterios establecidos.

Introducción. El uso indiscriminado de las Tecnologías de la Información y la Comunicación en la sociedad moderna ha provocado un estado de dependencia hacia los dispositivos tecnológicos y su conectividad a Internet, principalmente cuando a actividades de ocio y entretenimiento se refiere. Objetivos. Identificar la frecuencia de la Adicción a Internet y a los Videojuegos en bachilleres de México asociando dichas variables con su género, contexto y edad. Método. Se trabajó con una muestra incidental de 419 estudiantes bajo un diseño no experimental, transversal, descriptivo-correlacional. Se utilizó el Cuestionario de Adicción a Internet y a los Videojuegos para Adolescentes (CAIVA) de Chahín-Pinzón y Briñez (2018). Resultados. Se encontró que los estudiantes presentaron niveles bajos tanto en la adicción a los videojuegos como al Internet; también que, en el caso de la adicción a los videojuegos, quienes reportaron mayores niveles fueron los hombres; además, que no se advirtieron diferencias en ambos casos entre los estudiantes de contextos urbanos y rurales y; finalmente, que existían correlaciones significativas y negativas entre estas variables y la edad. Conclusiones. Resulta pertinente ampliar la presente línea de investigación, incorporando otras variables de estudio y otras metodologías que impacten favorablemente en la disminución de este tipo de problemáticas.

The objectives of this work were to identify the relationship between school adjustment, school climate and social support in high school students, compare these variables according to the sex of the participants and recognize the strength of the dimensions of the school climate and social support in the prediction of school adjustment. The sample consisted of 967 students. The instruments used were the Brief Scale of School Adjustment (BSAS-10), the School Climate Scale (CES) and the Family and Friends Social Support Scale (AFA-R). Significant differences were detected by sex. Low correlations were detected between the study variables. Through a binomial logistic regression analysis, a model was generated that considers the dimensions of the school climate, social support and sex in the prediction of school adjustment, being the support of friends the predictor of greater weight. The relevance of the variables studied to achieve an adequate school adjustment is confirmed and the promotion of actions to increase social support and improve the study environments in school communities are recommended.

El trabajo tuvo como objetivos identificar la relación entre el ajuste escolar, el clima escolar y el apoyo social en bachilleres, comparar dichas variables conforme al sexo de los participantes y reconocer la fuerza de las dimensiones del clima escolar y del apoyo social en la predicción del ajuste escolar. La muestra estuvo conformada por 967 estudiantes. Los instrumentos utilizados fueron la Escala Multi-dimensional Breve de Ajuste Escolar (EBAE-10), la Escala de Clima Escolar (CES) y la Escala de Apoyo Social Familiar y de Amigos (AFA-R). Se detectaron diferencias significativas por sexo y correlaciones bajas entre las variables estudiadas. Mediante un análisis de regresión logística bino-mial se generó un modelo que contempla las di-mensiones del clima escolar, el apoyo social y el sexo en la predicción del ajuste escolar, siendo el apoyo de amigos el predictor de mayor peso. Se constata la relevancia de las variables estudiadas para lograr un adecuado ajuste escolar y se reco-mienda la promoción de acciones para incrementar el apoyo social y mejorar los ambientes de estudio en las comunidades escolares.

Esta obra emerge de los proyectos investigativos y procesos de enseñanza aprendizaje que se suscitan en la academia de Ecuador. Los autores del presente libro tienen muchas cosas en común, pero entre las más relevantes están el ser docentes en niveles de educación superior y contar con la colaboración de estudiantes destacados. Además, todos ellos son apasionados por la investigación socioeducativa, el desarrollo sostenible y están en permanente búsqueda de superación de las problemáticas sociales que persisten. Como muestra de ello, nos encontramos con esta segunda entrega del libro “Lectura y Escritura Académica y Creativa II: Instrumentos que aportan al desarrollo humano”, en el que se esquematizan los resultados de diversas investigaciones que atienden principalmente al cambo educativo. . Estos estudios han organizados en cuatro SECCIÓNes: Sistematizaciones de Experiencias, Estudios de Caso, Historias de Vida y Estudios Multidisciplinares.

5 Figuras, Recent studies have shown that the formation of heterocyclic aromatic amines (HAAs) with the structure of aminoimidazoazaarene is produced by reaction of specific reactive carbonyls with ammonia and creatin(in)e. These carbonyl compounds, which are usually the limiting reagents, have multiple origins. Therefore, HAA formation cannot be considered to be produced as a consequence of a single process, such as the Maillard reaction, but of any process that generates the involved reactive carbonyls. In addition, inhibition of HAA formation should be related to the control of these reactive carbonyls: inhibiting their formation, using conditions that limit their reactivity, and promoting their trapping., This study was funded by the Ministerio de Ciencia e Innovación (MCIN) from Spain, the Agencia Estatal de Investigación (AEI) from Spain, and the Fondo Europeo de Desarrollo Regional (ERDF, a way of making Europe) from the European Union (Project RTI2018-096632-B-I00/AEI/ 10.13039/501100011033).

The main objective of this study was to identify sociodemographic and psychosocial variables capable of predicting risk eating behaviors (REB) in high school students. Participants were 988 adolescents (541 women and 447 men) between 14 and 18 years of age ( M = 16.79, SD = 1.50). In addition to the REB (Binge-purge, compensatory behavior and restriction), examined through the Brief Questionnaire on Risk Food Behaviors, the following psychosocial variables were also evaluated: family and friend support, school adjustment, victimization, suicidal ideation, academic stress, body dissatisfaction and depression; the sociodemographic variables included were: sex, age, hours of sleep per day and hours dedicated to the Internet or social networks. Through three multiple linear regression analyzes, one for each REB ( R 2 = .36, .16 and .55, respectively; all with p < .001), different predictive variables could be identified, among which stood out the body dissatisfaction, the depression and sex (women). The identification of these variables can contribute to the improvement of prevention strategies in terms of REB and eating disorders among adolescents. Resumen El objetivo principal de este estudio fue identificar variables sociodemograficas y psicosociales capaces de predecir las conductas alimentarias de riesgo (CAR) en estudiantes de bachillerato. Participaron 988 adolescentes (541 mujeres y 447 hombres) de entre 14 y 18 anos de edad ( M = 16.79, DE = 1.50). Ademas de las CAR (Atracon-purga, Medidas compensatorias y Restriccion), examinadas a traves del Cuestionario Breve de Conductas Alimentarias de Riesgo, fueron evaluadas las variables psicosociales siguientes: apoyo familiar y de amigos, ajuste escolar, victimizacion, ideacion suicida, estres academico, insatisfaccion corporal y depresion; mientras que las variables sociodemograficas incluidas fueron: sexo, edad, horas de sueno al dia y horas dedicadas al Internet o las redes sociales. Mediante tres analisis de regresion lineal multiple, uno para cada CAR ( R 2 = .36, .16 y .55, respectivamente; todas con p < .001), se pudieron identificar distintas variables predictivas, entre las que destacaron la insatisfaccion corporal, la depresion y el sexo (mujeres). La identificacion de estas variables puede contribuir a la mejora de las estrategias de prevencion en materia de CAR y, por ende, de los trastornos alimentarios entre adolescentes.

Objetivo: Formular un modelo explicativo de la autopercepción de la preparación docente para enfrentar los retos educativos de la emergencia sanitaria COVID-19 en profesores mexicanos de Educación Básica quienes han iniciado el ciclo escolar 2020-2021 en modalidad virtual. Método: Se trabajó un diseño no experimental de alcance explicativo. La muestra de tipo incidental quedó conformada por 2010 docentes provenientes de 15 Estados de la República Mexicana. Los datos fueron recabados a través de un cuestionario ad hoc constituido por 15 reactivos en torno a tres categorías: Dispositivos y conectividad, Apoyo familiar e institucional y Capacitación. Después de confirmar la relación entre la preparación docente con el resto de las variables, se ejecutó un análisis de regresión lineal múltiple mediante el método escalonado.Resultados:se obtuvo un modelo de nueve variables que explicaron el 34.4% de la varianza.Discusión y Conclusiones:se confirma que el dominio de las herramientas de comunicación remota, disponer de los dispositivos y recursos tecnológicos necesarios, emprender acciones de capacitación autogestiva y percibir un adecuado apoyo institucional y familiar, son factores que explican la autopercepción de la preparación docente al momento de realizar actividades de enseñanza remota.

4 Figuras.-- 2 Tablas, The reaction of 2-alkenals (crotonaldehyde and 2-pentenal) with hydroquinones (hydroquinone and tert-butylhydroquinone) and benzoquinones (benzoquinone, methylbenzoquinone, and methoxybenzoquinone) was studied as a potential route for the endogenous formation of naphthoquinones and anthraquinones in foods. Polycyclic quinones were produced at a low water activity, within a wide pH range, and in the presence of air. 9,10-Anthraquinone formation had an activation energy of 46.1 ± 0.1 kJ·mol−1, and a reaction pathway for the formation of the different naphthoquinones and anthraquinones is proposed. These reactions also took place in tea, therefore suggesting that the common tea pollutant 9,10-anthraquinone is also a process-induced contaminant. In fact, when four commercial teas (from a total of eight studied teas) were heated at 60 °C for 72 h, they significantly (p < 0.05) increased the amount of this toxicant. Reduction of 9,10-anthraquinone formation in teas is suggested to be carried out by reducing/scavenging its precursors., We are indebted to José L. Navarro for technical assistance. This study was supported by the Ministerio de Ciencia, Innovación y Universidades (MCIU) from Spain, the Agencia Estatal de Investigación (AEI) from Spain, and the Fondo Europeo de Desarrollo Regional (FEDER) from the European Union (Project RTI2018-096632-B-100).

Food processing is responsible for the destruction of some health hazards, but it is responsible for the formation of new ones. Among them, the formation of heterocyclic aromatic amines (HAAs) has received a considerable attention because of their carcinogenicity. In spite of this, HAA formation is still poorly understood. This study was undertaken to identify precursors and formation pathways for 2-amino-3-methylimidazo(4,5

9 Figuras, Polyphenols are a group of chemical substances found in plants, with immunomodulatory, antiproliferative, and anti-inflammatory properties that might be useful in the prophylaxis and treatment of graft-versus-host disease (GVHD). Polyphenolic extract (PE) obtained from extra virgin olive oil (EVOO) decreased the activation and proliferation of activated T cells. In addition, a decreased production of proinflammatory cytokines was observed upon exposure to PE. Western blot assays showed a marked inhibition of Akt phosphorylation and nuclear translocation of NF-κB in activated T cells. In a murine model of acute GVHD, we observed that mice that received a diet supplemented in PE (600 ppm) presented a higher survival rate and lower risk of developing GVHD when compared with the group that received a control diet. Histopathologic examination showed a significantly lower gut involvement in mice receiving PE, with a decrease in proinflammatory cytokines (IL-2, IL-17, and TNF-α) in serum and the reestablishment of butyrate concentration in the gut. In conclusion, PE obtained from EVOO exerted a potent immunomodulatory effect, reducing the activation and proliferation of activated T cells and the production of proinflammatory cytokines. In a murine model of acute GVHD, a PE-supplemented diet reduced the incidence and severity of the disease and increased survival after transplantation.

44 Páginas.-- 8 Figuras.-- 3 Tablas.-- 3Figuras y 1 tabla suplementarias, Lipid hydroperoxides have been shown to produce amino acid decarboxylations. Because thermal decomposition of lipid hydroperoxides produces free radicals and reactive carbonyls, and phenolic compounds have been shown to scavenger both of them, phenolics are expected to inhibit these reactions and this protection should depend on the structures of the involved phenolics. In this study, the effect of a wide array of phenolics and their mixtures on 2-phenylethylamine formation by phenylalanine degradation in the presence of the 13-hydroperoxide of linoleic acid (LOOH) was studied. LOOH increased considerably the formation of the amine, and phenolics mostly exhibiting an inhibitory role that depended on their structure. Thus, 1,3-diphenols decreased the formation of 2-phenylethylamine because of their carbonyl trapping abilities. In contrast, the inhibition of 1,2- and 1,4-diphenols was lower because they could not trap the reactive carbonyls produced by LOOH decomposition. In addition, their free radical scavenging was likely accompanied by the formation of quinones, which acted as reactive carbonyls. The function of all other phenolics could be calculated by adding the individual functions of the different diphenols present in their structures. In fact, experimental values obtained for both mixtures of phenolics and complex phenolics correlated well with the calculated values obtained from their constituting diphenols. All of these results suggest that, when the reaction mechanisms are known, it is possible to predict the behavior of complex phenolics on the basis of their structure., This study was supported in part by the European Union (FEDER funds) and the Plan Nacional de I + D of the Ministerio de Economía y Competitividad of Spain (project AGL2015-68186-R).

El presente trabajo tuvo como propósito identificar los índices de pensamiento mágico de estudiantes de distintos niveles educativos. La investigación se desarrolló con un diseño descriptivo, correlacional y transversal. La muestra ascendió a 513 estudiantes, 87 de secundaria, 212 de bachillerato y 214 de educación superior. El instrumento utilizado fue la escala de Pensamiento Mágico en su versión de 24 ítems con dos factores relacionados, la cual cuenta con los parámetros adecuados de validez y confiabilidad. En general, los resultados indican que el nivel de pensamiento mágico de los participantes puede interpretarse como una neutralidad que no corresponde a rasgos marcados de pensamiento mágico o de racionalidad; además, se encontraron diferencias significativas entre niveles educativos y el sexo de los estudiantes. Se sugiere emprender estudios para identificar el origen de tales resultados.

5 Figuras.-- 1 Tabla, Reactions involving reactive carbonyls, creatinine, and ammonia-producing compounds were investigated in order to clarify the formation of the heterocyclic aromatic amine (HAA) 2-amino-3,4-dimethylimidazo(4,5-f)quinoline (MeIQ). Obtained results showed that MeIQ was only produced when 2-butenal (crotonaldehyde) was present. Reaction yields depended on the pH, with a maximum around pH 6.5, and on concentrations of crotonaldehyde and creatinine. Ammonia was also required for MeIQ formation, but ammonia was produced by creatinine decomposition. The amount of MeIQ formed increased with reaction time, temperature, and oxygen content in the reaction atmosphere. Activation energy for MeIQ formation from crotonaldehyde, creatinine, and glutamine was 72.2 ± 0.4 kJ·mol−1. A reaction pathway that explains MeIQ formation is proposed. Obtained results suggest a main role of reactive carbonyls formed in foods (the food carbonylome) on HAA formation. In addition, they provide scientific basis for the understanding of how HAAs are formed and could be mitigated., We are indebted to José L. Navarro for technical assistance. This study was supported by the Ministerio de Ciencia, Innovación y Universidades (MCIU) from Spain, the Agencia Estatal de Investigación (AEI) from Spain, and the Fondo Europeo de Desarrollo Regional (FEDER) from the European Union (Project RTI2018-096632-B-100).

6 Figuras, Pyridines are produced during food processing and are important flavor compounds. In spite of that, their formation pathways are still poorly understood, in particular those related to 3-hydroxypyridines. In an attempt to fill this gap, this study describes, for the first time, precursors and reaction pathways leading to 3-hydroxypyridine formation. 3-Hydroxypyridines are produced by reaction of lipid-derived reactive carbonyls and ammonia-producing compounds and were studied by using gas chromatography coupled to mass spectrometry. Their main precursors resulted to be 4,5-epoxy-2-alkenals and 2,4-alkadienals. 3-Hydroxypyridines were produced at temperatures higher than 100 °C, at slightly basic pH values, and with an activation energy of about 50 kJ/mol. A reaction pathway that explains their formation in the course of the lipid oxidation pathway is proposed. The role of lipid oxidation on the production of 3-hydroxypyridines was confirmed by studying their formation in oxidized linseed and menhaden oils heated in the presence of glutamine., We are indebted to José L. Navarro for technical assistance. This study was supported by the Ministerio de Ciencia, Innovación y Universidades (MCIU) from Spain, the Agencia Estatal de Investigación (AEI) from Spain, and the Fondo Europeo de Desarrollo Regional (FEDER) from the European Union (Project RTI2018-096632-B-100).

6 Figuras, Reaction mixtures of reactive carbonyls and creatinine were submitted to high temperature and studied to identify the reactive carbonyl(s) responsible for 2-amino-3,8-dimethylimidazo[4,5-f]quinoxaline (MeIQx) formation. MeIQx was produced by reaction of acrolein and creatinine within a wide pH range and with an activation energy of 81.1 ± 1.4 kJ/mol. No additional reactants were required, although methylglyoxal, ammonia, and formaldehyde also participated in the reaction. Nevertheless, these additional reactants were produced in situ from either acrolein or creatinine. A reaction pathway that both explains the formation of MeIQx and is valid for the formation of other heterocyclic aromatic amines (HAAs) with the structure of quinoxaline is proposed. Obtained results demonstrate the key role of reactive carbonyls present in foods (the food carbonylome) on HAA formation. Because creatinine is ubiquitous in proteinaceous foods, the control of the food carbonylome seems to be the key point to control HAA formation in foods., We are indebted to José L. Navarro for technical assistance. This study was supported by the Ministerio de Ciencia, Innovación y Universidades (MCIU) from Spain, the Agencia Estatal de Investigación (AEI) from Spain, and the Fondo Europeo de Desarrollo Regional (FEDER) from the European Union (Project RTI2018-096632-B-100).

4 Figuras.-- 2 Tablas, The reactions of different lipid-derived reactive carbonyls with ammonia-producing compounds were studied to investigate the formation of pyridines in foods. 2-Alkyl, 3-alkyl-, and 2,5-dialkylpyiridines were produced by oligomerization of short-chain aldehydes in the presence of ammonia. Thus, acetaldehyde/crotonaldehyde mixtures and 2,4-alkadienals were the main responsible for the formation of 2-alkylpyridines; acrolein or 2,4-alkadienals were needed for the formation of 3-alkylpyridines; and 2-alkenals were responsible for the formation of 2,5-dialkylpyridines. On the contrary, 2,6-dialkylpyridines were produced by cyclization of unsaturated ketones. Reactions pathways for formation of these pyridines are proposed, and confirmed by isotopic labelling experiments. Aldehydes and ketones required for their formation are produced in the course of lipid oxidation. Therefore, pyridine formation seems to be an additional consequence of the lipid oxidation pathway. This new knowledge can employed for the optimization of reactions to achieve the desired targeted flavor generation during food processing., We are indebted to José L. Navarro for technical assistance. This study was supported in part by the European Union (FEDER funds), the Plan Nacional de I + D of the Ministerio de Economía y Competitividad of Spain (project AGL2015-68186-R), and the Programa Estatal de I + D + I of the Ministerio de Ciencia, Innovación y Universidades of Spain (project RTI2018-096632-B-100).

10 Figuras, Food processing is responsible for the destruction of some health hazards, but it is responsible for the formation of new ones. Among them, the formation of heterocyclic aromatic amines (HAAs) has received a considerable attention because of their carcinogenicity. In spite of this, HAA formation is still poorly understood. This study was undertaken to identify precursors and formation pathways for 2-amino-3-methylimidazo(4,5-f)quinoline (IQ). IQ was produced by reaction of acrolein, crotonaldehyde, creatinine, and ammonia. Reaction conditions were studied, and its activation energy (Ea) was determined to be 77.0 ± 1.3 kJ/mol. IQ formation was always accompanied by the formation of the HAA 2-amino-3,4-dimethylimidazo(4,5-f)quinoline (MeIQ), which was produced with an Ea of 72.2 ± 0.4 kJ/mol. A reaction pathway for the competitive formation of IQ and MeIQ is proposed. Obtained results demonstrate the significant role of reactive carbonyls (the food carbonylome) in HAA formation and provide evidences for designing HAA mitigation strategies., This study was supported by the Ministerio de Ciencia, Innovación y Universidades (MCIU) from Spain, the Agencia Estatal de Investigación (AEI) from Spain, and the Fondo Europeo de Desarrollo Regional (FEDER) from the European Union (Project RTI2018-096632-B-100).

10 Figuras, The formation of 6-(hydroxymethyl)pyridin-3-ol by ring expansion of 5-(hydroxymethyl)furfural (HMF) in the presence of ammonia-producing compounds was studied to determine the routes of formation of pyridin-3-ols in foods. 6-(Hydroxymethyl)pyridin-3-ol was produced from HMF in model systems, mostly at neutral pH values, as a function of reaction times and temperature and with an activation energy (Ea) of 74 ± 3 kJ/mol, which was higher than that of HMF disappearance (43 ± 4 kJ/mol). A reaction pathway is proposed, which is general for the formation of pyridin-3-ols from 2-oxofurans. Thus, it explains the conversions of furfural into pyridin-3-ol and of 2-acetylfuran into 2-methylpyridin-3-ol, which were also studied. When honey and sugarcane honey were heated, they produced different pyridin-3-ols, although 6-(hydroxymethyl)pyridin-3-ol was the pyridine-3-ol produced to the highest extent. Obtained results suggest that formation of pyridin-3-ols in foods is unavoidable when 2-oxofurans are submitted to thermal heating and ammonia (or ammonia-producing compounds) is present., This study was supported by the Ministerio de Ciencia, Innovación y Universidades (MCIU) from Spain, the Agencia Estatal de Investigación (AEI) from Spain, and the Fondo Europeo de Desarrollo Regional (FEDER) from the European Union (Project RTI2018-096632-B-100).

41 p.-- 6 Figuras.-- 1 Figura suplementaria, Thermal food processing has many beneficial consequences, although it also produces some unintentional undesired effects, such as the formation of potentially mutagenic and carcinogenic substances. Among them, the formation of heterocyclic aromatic amines (HAAs) has been related to the declared carcinogenicity of processed meats. In spite of this importance, HAA formation pathways remain mostly unknown, which avoids the design of targeted procedures to inhibit HAA appearance. The objective of this review is to collect information recently appeared that allow advancing in the understanding of how these compounds are produced. Particularly, the possibility that aminoimidazoazarenes are produced similarly to PhIP is discussed, including their formation by cyclizations and oligomerizations of aldehydes and creatinine under usual cooking conditions. Present data suggest that HAA formation might be related to the pool of carbonyl compounds existing in foods, the food carbonylome, which can be controlled by carbonyl-trapping agents, such as amine and phenolic compounds., We are indebted to José L. Navarro for technical assistance. This study was supported by the Ministerio de Ciencia, Innovación y Universidades (MCIU) from Spain, the Agencia Estatal de Investigación (AEI) from Spain, and the Fondo Europeo de Desarrollo Regional (FEDER) from the European Union (Project RTI2018-096632-B-100)

ResumenEl presente estudio tuvo como objetivo identificar una posible correlación entre los resultados del Examen General para el Egreso de la Licenciatura en Psicología y las siguientes variables: tipo de ingreso a la universidad, sexo, puntuación en la prueba de aptitud académica, y los promedios de ingreso y egreso de los estudiantes. Los resultados muestran diferencias estadísticamente significativas en el rendimiento del Examen General para el Egreso de la Licenciatura conforme al sexo y el tipo de ingreso. También se reportan correlaciones importantes entre los resultados de dicho examen con el puntaje de la prueba de aptitud. Se propone investigar la asociación de otras variables con el Examen General para el Egreso de la Licenciatura y, en su caso, elaborar estudios predictivos que sirvan de base tanto a la comprensión del fenómeno como al desarrollo de planes y de acciones tendentes a la mejora de los resultados académicos de los estudiantes.AbstractThis study sought to identify possible correlations between the results of the school exit examination for undergraduate psychology students and the following variables: means of admission to college, sex, score on the scholastic aptitude test, and the grade point averages of entering and graduating students. The results show significant differences in performance on the school exit examination according to the studentś sex and means of admission to the university. In addition, there were significant correlations between the results of the school exit examination and student scholastic aptitude test scores. The study suggests the need for more research to determine other variables associated with success on the exit exam, as well as the development of predictive studies that would both enhance our understanding of the phenomenon and aid in developing strategies for improving the academic performance of students.

4-Hydroxy-2-alkenals disappear in the presence of food phenolics (i.e., cathechin or quercetin), and the corresponding carbonyl–phenol adducts are produced. In an attempt to identify structure(s) of formed adducts, the reactions between model phenolics (resorcinol, 2-methylresorcinol, orcinol, and 2,5-dimethylresorcinol) and hydroxyalkenals (4-hydroxy-2-hexenal and 4-hydroxy-2-nonenal) were studied and the produced adducts were isolated by column chromatography and unambiguously characterized by one- and two-dimensional nuclear magnetic resonance and mass spectrometry as dihydrobenzofuranols (1), chromane-2,7-diols (2), and 2H-chromen-7-ols (3). These compounds were mainly produced at slightly basic pH values and moderate temperatures. Their activation energies (Ea) of formation were ∼25 kJ mol–1 for adducts 1, ∼32 kJ mol–1 for adducts 2, and ∼38 kJ mol–1 for adducts 3. A reaction pathway that explains their formation is proposed. All of these results confirm that, analogously to other lipid-derived carbonyl compounds, phenolics can trap 4-hydroxy-2-alkenals in an efficient way. Obtained results provide the basis for the potential detection of carbonyl–phenol adducts derived from hydroxyalkenals in food products., This study was supported in part by the European Union [Fonds Européen de Développement Économique et Régional (FEDER) funds] and the Plan Nacional de I + D of the Ministerio de Economía y Competitividad of Spain (Project AGL2015-68186-R).

20 Páginas.-- 3 Figuras, Different from the well-characterized function of phenolics as antioxidants, their function as lipid-derived carbonyl scavengers is mostly unknown. However, phenolics react with lipid-derived carbonyls as a function of the nucleophilicity of their reactive groups and the electronic effects and steric hindrances present in the reactive carbonyls. Furthermore, the reaction produces a wide variety of carbonyl–phenol adducts, some of which are stable and have been isolated and characterized but others polymerize spontaneously. This perspective updates present knowledge about the lipid-derived carbonyl trapping ability of phenolics, its competition with carbonyl–amine reactions produced in foods, and the presence of carbonyl–phenol adducts in food products., This study was supported in part by the European Union (FEDER funds) and the Plan Nacional de I+D of the Ministerio de Economía y Competitividad of Spain (Project AGL2015-68186-R).

© 2015 American Chemical Society. Comparative formation of both 2-phenylethylamine and phenylacetaldehyde as a consequence of phenylalanine degradation by carbonyl compounds was studied in an attempt to understand if the amine/aldehyde ratio can be changed as a function of reaction conditions. The assayed carbonyl compounds were selected because of the presence in the chain of both electron-donating and electron-withdrawing groups and included alkenals, alkadienals, epoxyalkenals, oxoalkenals, and hydroxyalkenals as well as lipid hydroperoxides. The obtained results showed that the 2-phenylethylamine/phenylacetaldehyde ratio depended upon both the carbonyls and the reaction conditions. Thus, it can be increased using electron-donating groups in the chain of the carbonyl compound, small amounts of carbonyl compound, low oxygen content, increasing the pH, or increasing the temperature at pH 6. Opposed conditions (use of electron-withdrawing groups in the chain of the carbonyl compound, large amounts of carbonyl compound, high oxygen contents, low pH values, and increasing temperatures at low pH values) would decrease the 2-phenylethylamine/phenylacetaldehyde ratio, and the formation of aldehydes over amines in amino acid degradations would be favored., This study was supported in part by the European Union (FEDER funds) and the Plan Nacional de I + D of the Ministerio de Economı́a y Competitividad of Spain (Project AGL2012-35627).

33 Páginas.-- 6 Figuras, The reaction between 4-oxo-2-alkenals (fumaraldehyde, 4-oxo-2-hexenal, and 4-oxo-2-nonenal) and phenolic compounds (resorcinol and 2-methylresorcinol) was studied to characterize the trapping ability of phenolic compounds for these lipid oxidation products. The reaction occurred rapidly under neutral or slightly basic conditions and different carbonyl-phenol adducts were produced. However, these compounds were unstable and their stabilization had to be achieved by means of either acetylation or reduction with sodium borohydride. Three different kinds of adducts were isolated and characterized by using mass spectrometry (MS) and 1D and 2D nuclear magnetic resonance spectroscopy (NMR). They were benzofuran-6-ols, 2,3,3a,8a-tetrahydrofuro[2,3-b]benzofuran-2,6-diols, and chromane-2,7-diols. Most of them were produced as mixtures of diasteromers and all of them had a carbonyl group in a free form or as hemiacetal. A reaction pathway that explains the formation of these compounds is proposed. These results provide the basis to understand the removal of 4-oxo-2-alkenals by phenolic compounds in foods., We are indebted to José L. Navarro for technical assistance. This study was supported in part by the European Union (FEDER funds) and the Plan Nacional de I + D of the Ministerio de Economía y Competitividad of Spain (project AGL2015-68186-R).

38 Páginas.-- 2 Tablas.-- 8 Figuras, Phenolics can act as either promoters or inhibitors in 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) formation. In an attempt to clarify the structure–activity relationship (SAR) of phenolics for this reaction, the formation of PhIP in mixtures of phenylalanine, creatinine, 13-hydroperoxide of linoleic acid (LOOH) or 4-oxo-2-nonenal, and a wide array of phenolics was studied in the presence and in the absence of oxygen. The obtained results suggested that those phenolics having a high carbonyl scavenging ability inhibited the formation of PhIP. On the other hand, those phenolics that mainly acted as free radical scavengers and, therefore, were easily converted into quinones promoted the formation of PhIP. Phenolics of the first type were m-diphenols and 1,3,5-triphenols. Phenolics of the second type were o- and p-diphenols. Other phenolics, like 1,2,3- and 1,2,4-triphenols, exhibited a behavior either as carbonyl scavengers or as free radical scavengers depending on ring substitutions. Among the studied derivatives, the presence of a carboxylic or a methoxyl group at certain positions inhibited their behavior as carbonyl scavengers and, therefore, promoted the formation of PhIP. A procedure to classify phenolics as either carbonyl or free radical scavengers is proposed., This study was supported in part by the European Union (FEDER funds) and the Plan Nacional de I + D of the Ministerio de Economía y Competitividad of Spain (project AGL2015-68186-R).

30 Páginas.-- 6 Figuras.-- 3 Figuras suplementarias, Phenolics can trap lipid-derived reactive carbonyls as a protective function that diminishes the broadcasting of the lipid oxidative damage to food macromolecules. In an attempt to clarify the trapping of 2,4-alkadienals by phenolics, this study analyzes the reactions of 2,4-hexadienal, 2,4-heptadienal, and 2,4-decadienal with 2-methylresorcinol. These reactions produced (E)-4-(alk-1-en-1-yl)-8-methyl-2,7-bis(prop-1-en-2-yloxy)chromanes, which were isolated and characterized by 1D and 2D NMR and MS. Carbonyl-phenol adduct formation was favored at pH > 7 and moderate temperatures (25–80 °C). Adducts were quantified and shown to be produced as a mixture of diastereomers. Diastereomers 2R,4S plus 2S,4R were formed to a higher extent than diastereomers 2R,4R plus 2S,4S under the different conditions assayed, although activation energies (Ea) for the formation of all of them was mostly the same (∼62 kJ·mol−1). These results show that phenolics can trap 2,4-alkadienals and provide the basis for the later detection of the formed adducts in food pro[ducts., We are indebted to José L. Navarro for technical assistance. This study was supported in part by the European Union (FEDER funds) and the Plan Nacional de I + D of the Ministerio de Economía y Competitividad of Spain (project AGL2015-68186-R).

© The Royal Society of Chemistry 2015. 2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) is produced by reaction of phenylacetaldehyde, the Strecker aldehyde of phenylalanine, with creati(ni)ne in the presence of formaldehyde and ammonia, which are formed in situ. Traditionally, the carbonyl compounds required for the formation of the PhIP ring were considered to be produced as a consequence of Maillard reaction between phenylalanine and carbohydrates. This review collects all recent evidence suggesting that lipids can also contribute to the Strecker degradation of phenylalanine and the formation of formaldehyde analogously to carbohydrates. Furthermore, lipid-derived reactive carbonyls not only contribute to PhIP formation but they can also be involved in PhIP fate observed in the presence of oxidized oils. This role has not been yet investigated for carbohydrate-derived reactive carbonyls but it might be hypothesised to take place because of the decrease of PhIP observed when an excess of monosaccharides is employed to study PhIP formation. All these results suggest that carbohydrates and lipids can contribute simultaneously to PhIP formation and fate. This is another example of the simultaneous contribution of both lipids and carbohydrates to the carbonyl chemistry that takes place in foods upon processing and/or storage. Furthermore, many of these conclusions can also be extended to the formation of other aminoimidazoazarenes with an imidazopyridine structure., This study was supported in part by the European Union (FEDER funds) and the Plan Nacional de I + D of the Ministerio de Economía y Competitividad of Spain (project AGL2012-35627).

6 Figuras; 3 Tablas; 33 Páginas, The reaction among flavor-relevant saturated aldehydes (propanal, 2-methylpropanal, butanal, 2-methylbutanal, 3-methylbutanal, pentanal, hexanal, and glyoxal) and phenolic compounds (resorcinol, 2-methylresorcinol, 2,5-dimethylresorcinol, and orcinol) was studied both to identify and to characterize the formed carbonyl–phenol adducts and to understand the differences in the carbonyl-trapping abilities of phenolic compounds. The obtained results showed that carbonyl-trapping by phenolics is selective and that the formation of carbonyl–phenol adducts depends on the structures of both the phenol and aldehyde involved. In relation to the phenolic derivative, the presence of groups that increase the nucleophilicity of phenolic carbons will increase the carbonyl-trapping ability of these compounds. On the other hand, the presence of groups that increase the steric hindrance of these positions without affecting nucleophilicity will inhibit the reaction. Analogously, the presence of branching at position 2 of the aldehyde will also inhibit the reaction by steric hindrance. All of these results suggest that the addition of phenolics to foods may change food flavor not only because of their sensory properties but also because they can modify the ratio among food odorants by selective reaction of phenolics with determined carbonyl compounds., This study was supported in part by the European Union (FEDER funds) and the Plan Nacional de I + D of the Ministerio de Economı́a y Competitividad of Spain (Project AGL2015-68186-R).

The reaction between m-diphenols (resorcinol, 2-methylresorcinol, 2,5-dimethylresorcinol, 3-methylphenol, orcinol, and phloroglucinol) and 2-alkenals (2-pentenal and 2-octenal) was studied in an attempt to understand the chemical pathways involved in the scavenging ability of m-diphenols for the 2-alkenals produced as a consequence of lipid oxidation. Phenols reacted chemically with 2-alkenals producing a number of 2H-chromenols, chromandiols, chromanols, and dihydropyrano[3,2-g]chromenes, which were isolated and identified by 1D and 2D nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). The identification of all these compounds resulted in the construction of a general pathway for these reactions. These results confirm that the 2-alkenal-scavenging ability of m-diphenols is a consequence of their structure. This is a complex reaction in which many different products are formed. The most stable products were the chromandiols. However, the main reaction products were the 2H-chromenols. These products were unstable and disappeared as a consequence of polymerisation and browning reactions. © 2014 Elsevier Ltd. All rights reserved., This study was supported in part by the European Union (FEDER funds) and the Plan Nacional de I+D of the Ministerio de Economía y Competitividad of Spain (project AGL2012-35627).