Electrochemistry in large unilamellar vesicles. The distribution of 1-naphthol studied by square wave voltammetry

1-Naphthol (NPh) behavior in water and in large unilamellar vesicles (LUVs) formed with the phospholipid 1,2-di-oleoyl-sn-glycero-3-phosphatidylcholine (DOPC) was studied by square wave (SWV) and cyclic voltammetry (CV) techniques and, compared with emission spectroscopy studies. In DOPC LUV media, the redox behavior of NPh shows that the molecule undergoes a partition process between two pseudophases, the water and the LUV bilayer. The NPh electrochemical responses allow us to propose a model to explain the electrochemical experimental results and, in conjunction with our measurements, to calculate the NPh partition constant (K) value between the pseudophases. The K value coincides with the one obtained through emission spectroscopy. Beside the K value, our electrochemical model allows us to calculate the diffusion coefficient (D_LUV) for DOPC LUV which coincides with the D_LUV value obtained through dynamic light scattering (DLS). Thus, our data clearly show that the electrochemical measurements could be a powerful alternative approach to investigate the behavior of non-ionic electroactive molecules embed in a confined environment such as the LUV bilayer.     

On the performance of the approximate parametrization algorithm for curves

In Pérez-Díaz et al. (2009) [5], the authors present an algorithm to parametrize approximately ?-rational curves, and they show that the Hausdorff distance, w.r.t. the Euclidean distance, between the input and output curves is finite. In this paper, we analyze this distance for a family of curves randomly generated and we empirically find a reasonable upper bound of the Hausdorff distance between each input and output curve of the family.     

Evaluation of plasma,high‐pressure and ultrasound processing on the stability of fructooligosaccharides

Fructooligosaccharides (FOS) are among the main carbohydrates with prebiotic activity, and they are the most applied functional carbohydrate ingredient in the food industry. FOS are known to hydrolyse when subjected to thermal processing, thus partially losing its functional properties. In this study, we evaluate whether three nonthermal technologies are suitable for processing FOS regarding its stability after processing. FOS were subjected to ultrasound, high‐pressure processing (HPP) and atmospheric cold plasma (ACP). The FOS solution, 70 g L^?1, was set at a concentration recommended for human intake. The treatments were carried out at operating conditions usually used for microbial inactivation in foods (HPP at 450 MPa for 5 min; US at 600–1200 W L^?1 for 5 min; ACP at 70 kV for 15–60 s). NMR and HPLC analysis of the FOS components showed that ACP, ultrasound and HPP have not induced any significant change on FOS concentration (<2.0%) nor on the degree of polymerisation of the FOS (<3.3%). Contrarily to what is reported for thermal treatments, these nonthermal technologies were considered suitable for FOS processing.     

Nutritional evaluation of lentil flours obtained after short-time soaking processes

Twenty-four short-time soaking (STS) processes were carried out to study the influence of some experimental variables (lentil/water ratio, temperature, illumination, elimination of the soaking medium and milling of the seeds) on the glucose, fructose, sucrose, total available soluble sugars, starch, vitamin B₁, vitamin B₂, available niacin, raffinose, ciceritol, stachyose, total !-galactosides and trypsin inhibitor activities of lentil flours obtained. The soaking process produced, in general, a reduction in the total available soluble sugars content of 8-70%. Glucose was not found in the raw lentils, but was present in the lentil flours obtained after soaking processes carried out in presence of light. Fructose increased in most of the experiments (22-967%) and sucrose decreased significantly (6-73%). Regarding the starch content, the soaking process produced a significant reduction (11-31%). The hydrosoluble vitamin content of lentils, in general, decreased or did not change. However, vitamin B₂ and available niacin increased significantly in some experiments, especially in those carried out with ground lentils. The !-galactoside content suffered a large reduction (12-58%) and TIA levels were reduced by 2-33%. From the results obtained, it can be established that STS affects the nutrients and antinutrients of lentils in a different way depending on the experimental conditions. Lentil flours with a low level of antinutritional factors and a high vitamin level are obtained with ground lentils at 42 °C.     

Lipolysis, proteolysis and sensory characteristics of a Spanish fermented dry-cured meat product (salchichón) with oregano essential oil used as surface mold inhibitor

The superficial antifungal activity of oregano essential oil (OEO) in Spanish fermented dry-cured sausages ("salchichón"), and its effects on lipolysis, proteolysis and sensory characteristics were evaluated. The surface application of OEO reduced mold contamination on the surface, without significantly affecting the drying process. To evaluate the intensity of lipolysis during the ripening process, the profile and content of free fatty acids were determined. The addition of OEO led to a higher amount of unsaturated fatty acids, but lipolysis was not greatly affected. Sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), which was used to qualitatively assess the proteolytic changes in the sarcoplasmic and myofibrillar proteins during the process, pointed to very similar patterns in all the sausages. OEO did not significantly affect the sensory properties, but increased hardness, resulting in a better texture. Therefore, a shorter ripening time may be necessary for sausages treated with OEO.     

Antioxidant activity and phenolic compounds in organic red wine using different winemaking techniques

Abstract: Wine phenolic composition depends on the grapes used to make wine and on vinification conditions. The occurrence of these biological compounds has stimulated numerous studies focused on understanding the mechanisms that influence their concentrations in wine. This article studied the effect of different vinification techniques on the antioxidant activity and on the phenolic compounds of red wine made from the variety of Monastrell grapes obtained by organic culture. To this purpose, 3 different vinification procedures were carried out: vinification after prolonged maceration, vinification with the addition of enological enzymes, and traditional vinification procedures (used as control).The results showed similar values of antioxidant activity in all 3 types of wine elaborated and found no differences in the concentrations of the different types of phenolic compounds in wine made with the 3 different methods. The evolution of antioxidant activity and phenolic compounds tested in wines during 3 mo of storage showed a similar pattern. Organic wine has acquired an important role in the economic world and its important, working in oenology to research in this field.     

Effect of protein quality on weight and composition of the carcass in pregnant and non pregnant rats

The effect of diets with different protein qualities on net weight and on the composition of the carcass (the animal being skinned and gutted) were studied in pregnant and non-pregnant rats of the Wistar breed. The animals were fed with diets containing the following protein sources: casein + 5% DL-methionine, beans and a mix of beans and wheat, all with a protein level of 14%. Percentage weight gains in the carcass were in all cases greater in non-gestating animals than in gestating animals. The water content of the body was similar in all the groups tested. The quality of protein did not affect nitrogen content; however, a smaller proportion of nitrogen was observed in gestating animals than in non-gestating animals. With respect to fat content of the carcass, a greater quantity of fat was observed in the bodies of gestating rats than in non-gestating rats, which was only significant in the case of the bean-wheat mix diet. Within each group of gestating and non-gestating rats, there was a greater quantity of fat in those animals fed with casein.