Estudio cinético termodinámico de la interacción intermolecular de antocianinas con goma de mezquite y sus fracciones

Mesquite gum is a highly branched polysaccharide that has demonstrated a great similarity with Arabic gum and even it has shown better functional properties than the latter. In this work it was found that mesquite gum is composed by three principal fractions with different molecular weights and chemical compositions, getting a rich polysaccharide fraction (F1) and two more fractions (F2 and F3) with higher protein content than that determined for the whole mesquite gum. Molecular weight of these fractions ranged from 1.81 x 104 to 5.23 x 105 Da; being the smallest for the fraction with the highest protein content. These results are in accordance with the hydrodynamic diameter data for the biopolymer solutions, in which as higher the protein content, a shorter hydrodynamic diameter was obtained. Protein contents ranged from 0.76 to 46.21% in the following order F1 < GM < F2 < F3. The carbohydrate and amino acid profiles contents were done for each biopolymer. It was found that the highest contents of these both groups were the saccharide Arabinose and the amino acids Proline and Hydroxyproline respectively. On the other hand, through the isolations and purification of the anthocyanins extracted from Roselle calyces, it was found that the raw extract displayed a concentration of total monomeric anthocyanins of 28.52 mg/gsolids using the cyainidin-3- glucoside as standard with a molar extinction coefficient ε=26, 900 cm-1mol-1, a characteristic absorbance between 490-550 nm and a molecular weight of 449.2g/mol. Also it was found that this extract showed an antioxidant activity equivalent to Trolox of 0.59 mM, which corresponds to an inhibition of 44.7% of the ABTS* radical. Chromatographic assays shown that Roselle raw extract is composed by two main anthocyanins: glycosilates of cyanindin and delphinidin. Nevertheless, because this work focuses to the anthocyanins – protein rich fraction biopolymers interaction, in order to avoid interferences, it was decided to work only with one anthocyanins. In the antocyanin isolation process, six fractions with different concentrations of both anthocyanins were obtained, and even when in all the fraction the presence of both anthocyanins remained, fraction F5A was chosen as the anthocyanin fraction rich in delphinidin with more than 90% respect the second one. Not only the mesquite gum fractions but also the whole mesquite gum, were subjected to an electrostatic interaction with the isolated anthocyanins, for these compounds the pH, ratio and concentration conditions were determined in order to establish the interaction window in function of pH to find the minimum stoichiometric electrostatic charge difference, and under these conditions the kinetic and thermodynamic properties were carried out. In these interaction assays, the main amino acids found in the biopolymers were used in order to determine if their residues in the backbone structure of the biopolymers are the responsible of such interactions, and by this way elucidate the possible interaction sites. Results from calorimetric studies displayed that some aminoacids shown high affinity for the anthocyanins, while some like glutamic acid and glycine did not provide a favorable result. In the same way, it can be seen that the stoichiometric parameter (n) when the biopolymers were used showed that the anthocyanins content required to interact with the protein fraction increases when the protein content increases, giving rise to ensure the existence of an interaction between flavonoids and protein fractions. So, it can be concluded that some exposed amino acid residues found in the whole mesquite gum and in its fractions take part in the complex formation. Nonetheless, the great molecular weight of these macromolecules represents an impairment for the interaction conditions optimization, resulting in a titanic labor the “exact” elucidation of which and haw many aminoacids participate in these reactions. Also it was found that the interfacial rheological characterization of these biopolymers did not display significant differences when the oil-water interfases in presence or absence of anthocyanins, this lead us to establish that the functional properties of the whole mesquite gum and its fractions remained constants. This led to conclude that it is possible to take advantage of the physicochemical properties of both chemical species to make them interact and to form stable intermolecular complexes, which are able to maintain their functional properties and in the case of mesquite gum fractions, to improve their properties respect to the whole gum. These results open the possibility to deepen this investigation, using other techniques for fractionation and isolation of the protein fraction in the biopolymers to a reasonable size so that techniques such as 1D and 2D NMR would be possible to determine the exact sites of binding and also assessing the functional properties of anthocyanins in the complex and its stability.La goma de mezquite es un polisacárido altamente ramificado que ha demostrado poseer una gran semejanza con la goma Arábiga e incluso ha presentado mejores propiedades funcionales. En este trabajo se encontró que la goma de mezquite está compuesta por tres fracciones principales con pesos moleculares y composiciones químicas distintas, obteniendo una fracción rica en polisacáridos (F1) y dos fracciones con una concentración de proteína mayores al encontrado para la goma de mezquite sin fraccionar (F2 y F3). Los pesos moleculares de estas fracciones se encontraron entre 1.81 x 104 a 5.23 x 105 Da, siendo menor para la fracción con el mayor contenido de proteína. Estos resultados están en concordancia con los resultados obtenidos para el diámetro hidrodinámico de estos biopolímeros en solución, donde conforme el contenido de proteína aumenta, el diámetro hidrodinámico tiende a disminuir. Las concentraciones de proteína variaron de manera creciente desde un 0.76 hasta un 46.21% de acuerdo con el siguiente orden F1 < GM < F2 < F3. Se realizó el perfil de carbohidratos y aminoácidos para estos biopolímeros, encontrando que las mayores concentraciones de estos grupos bioquímicos fueron de Arabinosa y de Prolina e Hidroxiprolina, respectivamente. Por otra parte, se realizó el aislamiento y purificación de antocianinas a partir de cálices de flor de Jamaica (Hibiscus sabdariffa L.). Se encontró que el extracto crudo presentó una concentración de 28.52 mgantocianinas monoméricas totales/gsólidos utilizando la cianidina-3-glucósido como patrón con un coeficiente de extinción molar de ε=26, 900 cm-1mol-1, una absorbancia característica entre 490-550 nm y un peso molecular de 449.2 g/mol. Se encontró que este extracto presentó una actividad antioxidante de 0.59 mM equivalente a Trolox correspondiente a un 44.7% de inhibición del radical ABTS*. Las pruebas de cromatografía mostraron que este extracto se compone de dos principales antocianinas glicosiladas: cianidina y delfinidina. Sin embargo, para verificar la interacción de antocianinas con biopolímeros que contienen una fracción proteica se decidió trabajar únicamente con delfinidina. Durante su proceso de aislamiento se obtuvieron seis fracciones con diferentes concentraciones y proporciones de las dos antocianinas registradas en el extracto crudo, y aunque en todas las fracciones ambas antocianinas se encontraron presentes, se decidió trabajar con la fracción F5A, debido a que ésta presentaba el contenido de delfinidina con más del 90% de concentración respecto a la segunda antocianina. Tanto las fracciones de la goma de Mezquite como la goma sin fraccionar se sometieron a una interacción electrostática con la fracción F5A aislada de un extracto de flor de Jamaica. Se determinaron las condiciones de pH, proporciones y concentraciones adecuadas para llevar a cabo dicha interacción a través de la estimación de la ventana de interacción de pH contra potencial zeta, en los cuales tanto los biopolímeros como las antocianinas presentaban la mínima diferencia estequiométrica de sus cargas. Bajo estas condiciones se estudiaron las propiedades cinéticas y termodinámicas de dicha interacción utilizando la técnica de calorimetría isotérmica de titulación. Estas pruebas también se realizaron utilizando los principales aminoácidos presentes en los biopolímeros con la finalidad de verificar si estos son los responsables de las interacciones electrostáticas, y de esta manera elucidar los posibles sitios de interacción existentes entre ambas especies químicas. Los resultados encontrados a partir de la calorimetría mostraron que algunos aminoácidos, que se encontraron en mayor cantidad en los biopolímeros, presentaron alta afinidad por las antocianinas, mientras que algunos otros como el ácido glutámico y la glicina no resultaron favorecidos por dicha interacción. De igual forma puede observarse que el parámetro estequiométrico (n) de este análisis para los biopolímeros muestra que la cantidad de antocianinas requeridas incrementa conforme la concentración de proteína también incrementa, dando pie a asegurar que sí existe interacción entre ambas especies químicas y que existe una relación con las interacciones entre antocianina-aminoácidos. Por tanto, puede decirse que los residuos expuestos de estos aminoácidos en las estructuras moleculares tanto de la goma de mezquite sin fraccionar como en sus fracciones sí tienen participación; sin embargo, el gran tamaño de estas macromoléculas representa un impedimento para optimizar las condiciones de interacción, resultando en una labor titánica la elucidación “exacta” de qué y cuántos residuos de aminoácidos interactúan. Por otra parte, se encontró que la caracterización reológica interfacial de estos biopolímeros no mostró diferencias significativas cuando las interfases aceite-agua están en presencia de antocianinas, lo cual nos permite decir que las propiedades funcionales de las fracciones de la goma de mezquite, así como de la goma sin fraccionar se mantuvieron constantes aún para los complejos con antocianinas. Lo anterior llevó a concluir que es posible aprovechar las propiedades fisicoquímicas de ambas especies (GM y antocianinas) para hacerlas interaccionar y formar complejos intermoleculares estables, capaces de mantener sus propiedades funcionales. Estos resultados abren la posibilidad para profundizar en dicha investigación, utilizando otro tipo de técnicas de fraccionamiento y aislamiento de la fracción proteica de cada una de las fracciones hasta un tamaño razonable, de manera que por técnicas como RMN en 1D y 2D sea posible determinar los sitios exactos de unión así como poder evaluar las propiedades funcionales de las antocianinas en el complejo y su estabilidad

EFFECT OF Cr AND Pb ON THE ACTIVITY OF ANTIOXIDANT ENZYMES IN A CELL SUSPENSION CULTURE OF Jatropha curcas

Jatropha curcas is a tolerant and accumulator plant of heavy metals (HMs). Little is known about the mechanisms behind this ability. It is suggested that antioxidant enzymes might participate; however, there are no studies reporting the relationship between the activities of antioxidant enzymes and the presence of HMs in an in vitro cell suspension culture of J. curcas. The aim of this study was to determine the effect of chromium (Cr) or lead (Pb) at 0.0 to 3.0 mM on the activity of three antioxidant enzymes superoxide dismutase (SOD), catalase (CAT), and peroxidase (POX) through the growthofcellsuspensioncultures(CSC)ofJ.curcas. Theactivitydisplayedbythoseenzymeswasstatisticallysignificant (P≤0.05) when Cr or Pb was used. The greatest enzymatic activity was noted at the first hour of culture for SOD and at five h for POX and CAT. After 192 h, the activity of these three enzymes decreased, which coincided with the exponential growth phase of the cell culture. The results indicated that there is a close relationship between the presence of Cr and Pb and SOD, CAT, and POX activities in a cell suspension culture of J. curcas, which can explain the plant’s capability for tolerating and accumulating high concentrations of Cr and P

Determination of the minimum integral entropy, water sorption and glass transition temperature to establishing critical storage conditions of beetroot juice microcapsules by spray drying

The aim of this work was to microencapsulate beetroot juice (BJ) (Beta vulgaris L.) by spray-drying using as protective colloid gum Arabic. The adsorption isotherms of the microcapsules and the minimum integral entropy (∆S int)T were determined at 25, 35 and 40 ◦C. The glass transition temperature (Tg) was measured by differential scanning calorimetry and modeled by GordonTaylor equation. The water contents-water activity (M-aW ) sets obtained from (∆S int)T , and critical water content (CWC) and critical water activity (CWA) from the Tg were similar, being in the range of water content of 5.11-7.5 kg H2O/100 kg d.s. and in the water activity range of 0.532-0.590. These critical storage conditions were considered as the best conditions for increase the stability of the microcapsules, where the percentage of retention Betanin in the microcapsules was higher compared with other storage conditions in the temperature and aw range studied. Keywords: beetroot juice, microcapsules, minimum integral entropy, glass transition temperature, critical water content, critical water activity

Storage stability and physicochemical properties of passion fruit juice microcapsules by spray-drying

The aim of this work was to microencapsulate passion fruit juice (PFJ) by spray-drying in two dierent biopolymers blends: Gum Arabic-mesquite gum-maltodextrin DE-10 (GA17-MG66-MD17 and GA17-MG-17-MD66), yielding the microcapsules MGA17-MG66-MD17 and MGA17-MG17-MD66. The spray-dried passion fruit microcapsules were analyzed for physicochemical properties (moisture content, water activity, powder particle size), quality properties (hygroscopicity, dispersibility, rehydration time), and reconstituted product properties (total color change and vitamin C retention). The minimum integral entropy of the microcapsules was determined at 25, 35, and 40 °C, and the resulting water activities (aW) were 0.447, 0.505, 0.629 for MGA17-MG66-MD17 and 0.383, 0.414, 0.605 for MGA17-MG17-MD66, respectively. These temperatures-aW sets were considered as the most adequate conditions for achieving maximum storage stability of the microcapsules. The best vitamin C retention level occurred at 25 °C, aW = 0.447 for MGA17-MG66-MD17, and at 25 °C, aW = 0.383 for MGA17-MG17-MD66

Effect of gelled inner aqueous phase rheology on the colour degradation of muitle aqueous extracts incorporated into water-in-oil-in-water double emulsions

The aim of this work was to study different W1/O/W2 double emulsions in preserving color muitle aqueous extract (MAE), for which the work was divided into two fold, formulation and analysis of primary emulsion W1/O and W1/O/W2 double emulsions. Sodium alginate (SA), xanthan gum, guar gum, locust bean gum were used as gelling agents of MAE, and it was found that SA produced inner aqueous phase with enhanced viscoelastic properties, resulting in a W1/O primary emulsion with more uniform mean droplet size and distribution than when using the other gelling agents or ungelled MAE. Subsequently W1/O/W2 double emulsions were produced containing MAE gelled with SA or ungelled in the inner aqueous phase stabilized using pure gum Arabic (GA) or a blend of GA-mesquite gum (MG) in a 70:30 ratio in the outer aqueous phase. The double emulsion formulated with gelled MAE and 70:30 GA-MG blend exhibited more uniform mean inner water and outer oil droplet sizes, and protected best the anthocyanins contained in MAE to preserve its color when exposed to 8 h sunlight, providing a half-time life (t1/2) of 55.23 h. The double emulsion formulated with ungelled MAE and stabilized with pure GA displayed a t1/2 of 7.40 h. Keywords: double emulsions, muitle aqueous extract, gelling agents, viscoelastic properties, droplet size, half-time life

Moisture sorption properties and storage stability conditions of a nutraceutical system microencapsulated by spray drying

The adsorption isotherms of a nutraceutical system microencapsulated by spray drying were determined at 20, 35 and 40 °C. Experimental data of the isotherms were fitted using the GAB and Caurie models and the integral thermodynamic functions (enthalpy and entropy) were estimated by the Clausius-Clapeyron equation. The Kelvin and Halsey equations were adequate for calculation of pore radius which varied from 0.67 to 8.15 nm. The point of maximum stability (minimum integral entropy) was found between 3.61 and 3.81 kg H2O/100 kg d.s. (corresponding to water activity, aW, of 0.19-0.37). Enthalpy-entropy compensation for the microcapsules showed two isokinetic temperatures. The first isokinetic temperature was observed at low moisture contents (< 3.81 kg H2O/100 kg d.s.) and was controlled by changes in the entropy of water, whereas the second isokinetic temperature was considered to be enthalpy-driven (3.81-20 kg H2O/100 kg d.s.). Keywords: sorption isotherms, pore radius, minimum integral entropy, enthalphy-entropy compensation, water activity

Altimetry for the future: Building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the ‘‘Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion

Height and body-mass index trajectories of school-aged children and adolescents from 1985 to 2019 in 200 countries and territories: a pooled analysis of 2181 population-based studies with 65 million participants

Summary Background Comparable global data on health and nutrition of school-aged children and adolescents are scarce. We aimed to estimate age trajectories and time trends in mean height and mean body-mass index (BMI), which measures weight gain beyond what is expected from height gain, for school-aged children and adolescents. Methods For this pooled analysis, we used a database of cardiometabolic risk factors collated by the Non-Communicable Disease Risk Factor Collaboration. We applied a Bayesian hierarchical model to estimate trends from 1985 to 2019 in mean height and mean BMI in 1-year age groups for ages 5–19 years. The model allowed for non-linear changes over time in mean height and mean BMI and for non-linear changes with age of children and adolescents, including periods of rapid growth during adolescence. Findings We pooled data from 2181 population-based studies, with measurements of height and weight in 65 million participants in 200 countries and territories. In 2019, we estimated a difference of 20 cm or higher in mean height of 19-year-old adolescents between countries with the tallest populations (the Netherlands, Montenegro, Estonia, and Bosnia and Herzegovina for boys; and the Netherlands, Montenegro, Denmark, and Iceland for girls) and those with the shortest populations (Timor-Leste, Laos, Solomon Islands, and Papua New Guinea for boys; and Guatemala, Bangladesh, Nepal, and Timor-Leste for girls). In the same year, the difference between the highest mean BMI (in Pacific island countries, Kuwait, Bahrain, The Bahamas, Chile, the USA, and New Zealand for both boys and girls and in South Africa for girls) and lowest mean BMI (in India, Bangladesh, Timor-Leste, Ethiopia, and Chad for boys and girls; and in Japan and Romania for girls) was approximately 9–10 kg/m2. In some countries, children aged 5 years started with healthier height or BMI than the global median and, in some cases, as healthy as the best performing countries, but they became progressively less healthy compared with their comparators as they grew older by not growing as tall (eg, boys in Austria and Barbados, and girls in Belgium and Puerto Rico) or gaining too much weight for their height (eg, girls and boys in Kuwait, Bahrain, Fiji, Jamaica, and Mexico; and girls in South Africa and New Zealand). In other countries, growing children overtook the height of their comparators (eg, Latvia, Czech Republic, Morocco, and Iran) or curbed their weight gain (eg, Italy, France, and Croatia) in late childhood and adolescence. When changes in both height and BMI were considered, girls in South Korea, Vietnam, Saudi Arabia, Turkey, and some central Asian countries (eg, Armenia and Azerbaijan), and boys in central and western Europe (eg, Portugal, Denmark, Poland, and Montenegro) had the healthiest changes in anthropometric status over the past 3·5 decades because, compared with children and adolescents in other countries, they had a much larger gain in height than they did in BMI. The unhealthiest changes—gaining too little height, too much weight for their height compared with children in other countries, or both—occurred in many countries in sub-Saharan Africa, New Zealand, and the USA for boys and girls; in Malaysia and some Pacific island nations for boys; and in Mexico for girls. Interpretation The height and BMI trajectories over age and time of school-aged children and adolescents are highly variable across countries, which indicates heterogeneous nutritional quality and lifelong health advantages and risks

Rising rural body-mass index is the main driver of the global obesity epidemic in adults

Body-mass index (BMI) has increased steadily in most countries in parallel with a rise in the proportion of the population who live in cities(.)(1,2) This has led to a widely reported view that urbanization is one of the most important drivers of the global rise in obesity(3-6). Here we use 2,009 population-based studies, with measurements of height and weight in more than 112 million adults, to report national, regional and global trends in mean BMI segregated by place of residence (a rural or urban area) from 1985 to 2017. We show that, contrary to the dominant paradigm, more than 55% of the global rise in mean BMI from 1985 to 2017-and more than 80% in some low- and middle-income regions-was due to increases in BMI in rural areas. This large contribution stems from the fact that, with the exception of women in sub-Saharan Africa, BMI is increasing at the same rate or faster in rural areas than in cities in low- and middle-income regions. These trends have in turn resulted in a closing-and in some countries reversal-of the gap in BMI between urban and rural areas in low- and middle-income countries, especially for women. In high-income and industrialized countries, we noted a persistently higher rural BMI, especially for women. There is an urgent need for an integrated approach to rural nutrition that enhances financial and physical access to healthy foods, to avoid replacing the rural undernutrition disadvantage in poor countries with a more general malnutrition disadvantage that entails excessive consumption of low-quality calories.Peer reviewe

Altimetry for the future: building on 25 years of progress

In 2018 we celebrated 25 years of development of radar altimetry, and the progress achieved by this methodology in the fields of global and coastal oceanography, hydrology, geodesy and cryospheric sciences. Many symbolic major events have celebrated these developments, e.g., in Venice, Italy, the 15th (2006) and 20th (2012) years of progress and more recently, in 2018, in Ponta Delgada, Portugal, 25 Years of Progress in Radar Altimetry. On this latter occasion it was decided to collect contributions of scientists, engineers and managers involved in the worldwide altimetry community to depict the state of altimetry and propose recommendations for the altimetry of the future. This paper summarizes contributions and recommendations that were collected and provides guidance for future mission design, research activities, and sustainable operational radar altimetry data exploitation. Recommendations provided are fundamental for optimizing further scientific and operational advances of oceanographic observations by altimetry, including requirements for spatial and temporal resolution of altimetric measurements, their accuracy and continuity. There are also new challenges and new openings mentioned in the paper that are particularly crucial for observations at higher latitudes, for coastal oceanography, for cryospheric studies and for hydrology. The paper starts with a general introduction followed by a section on Earth System Science including Ocean Dynamics, Sea Level, the Coastal Ocean, Hydrology, the Cryosphere and Polar Oceans and the “Green” Ocean, extending the frontier from biogeochemistry to marine ecology. Applications are described in a subsequent section, which covers Operational Oceanography, Weather, Hurricane Wave and Wind Forecasting, Climate projection. Instruments’ development and satellite missions’ evolutions are described in a fourth section. A fifth section covers the key observations that altimeters provide and their potential complements, from other Earth observation measurements to in situ data. Section 6 identifies the data and methods and provides some accuracy and resolution requirements for the wet tropospheric correction, the orbit and other geodetic requirements, the Mean Sea Surface, Geoid and Mean Dynamic Topography, Calibration and Validation, data accuracy, data access and handling (including the DUACS system). Section 7 brings a transversal view on scales, integration, artificial intelligence, and capacity building (education and training). Section 8 reviews the programmatic issues followed by a conclusion