Fruitomics: The importance of combining sensory and chemical analyses in assessing cold storage responses of six peach (Prunus persica L. Batsch) cultivars

Cold storage is used to extend peach commercial life, but can affect quality. Quality changes are assessed through the content of nutritionally relevant compounds, aroma, physical characters and/or sensorially. Here, six peach and nectarine cultivars were sampled at commercial harvest and after 7 days of 1 °C storage. A trained panel was used to evaluate sensorial characters, while carotenoids, phenolics, vitamin C, total sugars, and qualitative traits including firmness, titrable acidity and soluble solid content were integrated with volatile organic compound (VOC) analysis previously reported. The different analyses reveal interesting patterns of correlation, and the six cultivars responded differently to cold storage. Sensory parameters were correlated with 64 VOCs and seven intrinsic characters. Acidity, firmness, and 10 VOCs were strongly negatively correlated with harmony and sweetness, but positively correlated with bitterness, astringency, and crunchiness. In contrast, Brix, b-carotene, and six VOCs were positively correlated with harmony and sweetness

18-crown-6-sodium cholate complex: thermochemistry, structure and stability

18-crown-6, one of the most relevant crown ethers, and sodium cholate, steroidal surfactant classified as natural bile salt, are components of novel, synthesized coordination complex ; 18-crown-6-sodium cholate (18C6•NaCh). Like crown ethers, bile salts act as building blocks in supramolecular chemistry in order to design new functionalized materials with a desired structure and properties. In order to obtain thermal behavior of this 1:1 coordination complex, thermogravimetry and differential thermal analysis were used, as well as microscopic observations and differential scanning calorimetry. Temperature dependent infrared spectroscopy (IR) gave a detailed view into phase transitions. The structures during thermal treatment were observed with powder X-ray diffraction, and molecular models of the phases are made. Hard, glassy, colorless compound 18C6•NaCh goes through crystalline – crystalline polymorphic phase transitions at higher temperatures. The room temperature phase is indexed to a triclinic lattice, while in the high temperature phases molecules take randomly one of the two different configurations in the unit cell, resulting in the 2-fold symmetry. The formation of cholesteric liquid crystalline phase occurs simultaneously with partial decomposition, followed by the isotropisation with simultaneous and complete decomposition at much higher temperature, as obtained by IR. The results provide valuable information about the relationship between molecular structure, thermal properties, and stability of the complex, indicating the importance of an appropriate choice of cation, amphiphilic, and crown ether unit in order to synthesize compounds with desired behavior

Temperature dependence of Water Self-Diffusion in the Gel phase of a Potassium Palmitate System

The temperature dependence of water self-diffusion in the gel and liquid crystalline phases of the potassium palmitate/water system was examined using pulsed field gradient spin-echo (PGSE) low resolution NMR experiments. The temperature dependence of the water self-diffusion in lamellar and hexagonal phases was characterised by trends parallel to pure water. The average ”two-site” self- diffusion model was used to analyse the composition dependence of the self-diffusion coefficients. Temperature dependence of water self-diffusion in the gel phase presented different and interesting behaviour. The slopes of the Arrhenius self-diffusion were strongly composition dependent. The results were interpreted as a dependence on $T$ of the bound water fraction, while the self-diffusion obstruction factor was considered constant

Translational Diffusion and Other Physicochemical Properties of a Bolaform Surfactant in Solution.

Some physicochem. properties were studied for a synthetic amphiphile having 2 azacrown ether groups as polar heads (joined to both ends of a C16 alkyl chain) were studied. According to self-diffusion, viscosity, and surface tension trends (as well as the phase diagram), such an α-ω compd. forms large aggregates (presumably vesicles) and exhibits consolute phenomena. Its behavior can be considered intermediate between that of vesicle-forming lipids and that of nonionic surfactants

Novel gel-niosomes formulations as multicomponent systems for transdermal drug delivery

The percutaneous permeation profiles of sulfadiazine sodium salt, propranolol hydrochloride and tyrosol from novel liquid crystal-niosomes formulations as multicomponent systems, were investigated. The new carriers were prepared from mixture of water/surfactant, AOT or Pluronic L64 as anionic and nonionic surfactants, respectively, in order to obtain lamellar LLC phases. The same surfactants were used to prepare also the vesicular systems (niosomes) that were added to the corresponding gel. The obtained multicomponent drug carrier was characterized by deuterium nuclear magnetic resonance spectroscopy, in order to understand if the introduction of the drug or drug-loaded niosomal suspension, as third component in the formulations, could influence the microstructure of the system and then the drug delivery across the skin. Simple AOT and L64-based niosomal formulations and LLCs phases were then prepared and used as control. Different drugs percutaneous availability was achieved, and the results revealed that the obtained gel-niosomes carriers were affected by the chemical structure of the drugs and by their affinity for the components. As a consequence these systems could be proposed as novel transdermal drug delivery systems, since they were found able to control the percutaneous permeation of small drugs across the skin. (C) 2013 Elsevier B.V. All rights reserved

Pulsed field gradient spin-echo NMR experiments in micellar solutions of the water/cetyltrimethylammonium bromide system

Pulsed Field Gradient NMR experiments, in their original time domain, have been carried out to separate both water and surfactant self-diffusion coefficients in the micellar solution of the system cetyltrimethylammonium bromide/water. These results have been supported by those obtained by NMR experiments performed with a Fourier Transform spectrometer. The water self-diffusion coefficients were used to calculate the obstruction effect of the micellar aggregates in accordance with a stoichiometric model already used for lyotropic mesophases. It was found that the micellar aggregates change shape with the concentration and are characterized by an average hydration number of approximately 9 $+/-$ 3

Micelle Formation and Phase Equilibria in a Water-Trifluoroethanol-Fluorocarbon Surfactant System.

The soln. behavior of the fluorinated surfactant tetraethylammonium perfluorooctane-sulfonate, PFOS, in water-trifluoroethanol, TFE, mixts. has been investigated by surface tension, elec. conductance, and PGSE (pulsed gradient spin-echo) NMR self-diffusion methods. Addn. of progressive amts. of TFE in the solvent has little influence on the crit. micellar concn., CMC. Conversely, self-diffusion, counterion binding, and the surface pressure at the CMC are significantly affected by added fluoroalkanol. The above effects have been explained in terms of the solvent viscosity, dielec. permittivity, and surface activity, resp. The complete phase behavior of the above system has been drawn, and the phase boundaries were detd. According to the above findings, added surfactant promotes the sepn. of the homogeneous solvent mixt. into two coexisting fluid phases. The obsd. behavior was rationalized on thermodn. grounds