Search results for "RMN"

Evaluation of Late-Maturing Peach and Nectarine Fruit Quality by Chemical, Physical, and Sensory Determinations

2019

In this work, both analytical and sensory determinations were carried out to evaluate the quality of yellow (&lsquo

NMR structure determination of (11E)-trinervita-1(14),2,11-triene, a new diterpene from sexual glands of termites

2005

Graphical Abstract Full-size image; International audience; Female alates of Nasutitermes ephratae termites from Guadeloupe and Nasutitermes sp. from Brazil produce a diterpene hydrocarbon of the molecular formula C20H30 as the main component of their tergal gland secretion. Analysis of NMR, IR, and mass spectra of the diterpene led to a structure of (11E)-trinervita-1(14),2,11-triene. Based on a comparison with the published oxygenated trinervitane skeleton from termites we prefer the enantiomer with absolute configurations (4R,7S,8R,15S,16S). The suggested structure is supported by ab initio quantum chemical calculation of 1H and 13C chemical shifts for the optimized geometry of the molec…

Firming of fruit tissues by vacuum infusion of pectin methylesterase: Visualisation of enzyme action

2008

 ; Apple pieces were vacuum-impregnated with either a pectin methylesterase (PME) and calcium solution or with water prior to pasteurization. Pasteurized apple pieces impregnated with PME and calcium showed a significantly higher firmness. Moreover, solid state C-13 NMR spectroscopy of apple cell wall residues revealed an increase of their molecular rigidity. Exogenous PME addition involved a decrease from 82% to 45% of apple pectin degree of methyl-esterification. Microscopic observations of apple slices immunolabelled with antibodies specific for pectins showed that (i) demethyl-esterification was more intense in the cell wall region lining intercellular spaces (demonstrating a key role f…

Martínez Calvo, Javier, El derecho al olvido digital como remedio frente a la hipermnesia de internet, Aranzadi, Cizur Menor (Navarra), 2021, 236 pp.

2021

Interacción entre ácidos nucleicos y ligandos de bajo peso molecular: mecanismos moleculares de reconocimiento específico

2015

Los ácidos nucleicos desempeñan una gran variedad de funciones bioquímicas y son moléculas básicas para la vida. El estudio de sus complejos con moléculas de bajo peso molecular es esencial para la búsqueda de nuevos agentes terapéuticos basados en la interacción con estas biomoléculas. Tras analizar la estructura de los ácidos nucleicos y los fundamentos de las técnicas experimentales utilizadas, esta tesis se centra en primer lugar en el estudio de la interacción entre ligandos bisnaftalimídicos antitumorales y diferentes secuencias de ADN, con el objetivo de identificar los mecanismos de reconocimiento específico del ADN por parte de estos compuestos. Utilizando una combinación de técnic…

1H NMR methodologies applied in the thermodynamic and structural characterization of organic supramolecular complexes

2021

Orientador: Anita Jocelyne Marsaioli Tese (doutorado) - Universidade Estadual de Campinas, Instituto de Química Resumo: Nesta tese consiste no estudo de interações supramoleculares utilizando diferentes metodologias de Ressonância Magnética Nuclear de hidrogênio (RMN de 1H), tais como ROESY 1D, RMN-DOSY e RMN-STD. Os sistemas supramoleculares foram abordados em dois casos de estudo diferentes. O Capítulo I tem como objeto de estudo interações do fármaco Dapsona com diferentes carreadores de fármacos (ß-CD, SBE-ß-CD e lipossoma de EPC), com a finalidade de encontrar formulações nas quais a Dapsona seja mais solúvel. Os complexos binários e ternário formados foram determinadas por medidas de …

Hybrid ferrocene ligands (P, N) : synthesis, coordination to metals and applications in arylation coupling catalysis

2017

The research theme developed during this thesis concerns the development of new hybrid ferrocene hybrid (P, N) ligands with controlled conformation, robust and stable to air. These hybrid tetradent ligands comprise two types of coordinating functions with distinct steric and electronic properties. Their coordination chemistry with metals such as gold or palladium has been studied and some isolated Au (I) complexes have been used in the arylation coupling catalysis of aryl iodides.

WITHIN TREE AND ORCHARD VARIABILITY OF SILVER KING PEACH (PRUNUS PERSICA (L.) BATSCH) FRUIT QUALITY

2012

The variability of crop quality accounts for most of seasonal variation of farmers’ incomes, since fruit value mostlydepends on its size and overall quality. Canopy architecture and orchard lay-out are mainly responsible for within tree environment and allocation, which in turn, account for fruit quality and its variability. Little is known about within tree and between trees variability resulting from different planting and training systems. A positive relationship has been measured in peach between PAR and TEAC (Motisi et al., 2005; Scalzo et al., 2005; Motisi et al., 2008). This study was carried out to measure within tree and orchard variability of fruits of the early ripening ‘Silver K…

STUDY ON THE TUNNEL PASTEURIZER ON TABLE OLIVES PROCESSING

2015

The application of heat treatment is particularly important in maintaining the organoleptic characteristics of fermented agro-food products, which potential consumers perceive as reflecting the quality of these foodstuffs. However, heat treatments can be cause of deterioration of many quality parameters of agro-food products, including texture, intended as the consistency of the pulp. In this study 'Nocellara del Belice' table olives produced in 2010 and packaged in glass jars were subjected to pasteurization at industrial scale using a tunnel pasteurizer with a core temperature of 75°C for 8 min. The aim of the study was to mechanically evaluate the pulp texture evolution that contributes …

Non-destructive determination of ‘Big Bang’ nectarine quality and harvest maturity

2021

In nectarines, potential shelf life and quality at consumption are closely related to the ripeness stage of fruit at harvest. Usually, the harvest is based on color, firmness, sugar and acids content of fruit, although these determinations are carried out through destructive methods and in a limited number of samples. The technique of Vis/Nir spectroscopy is used for the development of a non-destructive index based on the difference of absorbance (IDA) between two wavelengths near the absorption peak of chlorophyll-a, and it allows monitoring of changes in ripeness processes directly in the field. The objective of this paper is to track changes in quality that occur during nectarine ripenes…