Separation of Acylglycerides Obtained by Enzymatic Esterification Using Solvent Extraction

New avenues to add value to glycerol are currently being explored. One of them is the synthesis of structured lipids through glycerol esterification. In this work we have analyzed the recovery and purification of dicaprin obtained by esterification of glycerol with capric acid (C) in heptane, mediated by Lipozyme RM IM. This is an intermediate step to obtain lipids MLM. In the first stage, the diglyceride synthesis MGM (being G a central HC–OH) was carried out. When M = C, the diglyceride is CGC. Recovery of the diglyceride CGC is required to carry out the esterification of the sn-2 position with palmitic acid (P), thus obtaining the triglyceride CPC. Different solvents were evaluated using Ecofac 1.0 (a molecular design software solvent) through a theoretical approach to explore the best solvents for the acylglycerides separation. Then, the performance of the selected solvents to separate dicaprin from mono and tricaprin was experimentally studied in a liquid–liquid extraction process. Previously, the remaining fatty acid had been neutralized. With liquid–liquid extraction in three simple steps, using ethanol/water, 94 % of the dicaprin obtained by enzymatic esterification was recovered with a purity of 89 % (wt%). It was also possible to obtain dicaprin with a purity of 97 % but with a yield of 56 %.     

Effect of processing for saponin removal on fungal contamination of quinoa seeds (Chenopodium quinoa Willd.)

Incidence of fungal contamination of quinoa seeds from three locations (Salar de Uyuni, Bolivia; Salta and Tucumán provinces, Argentina) was analyzed in samples with and without treatment to remove saponins (wet method). In processed samples, the percentage of infection was reduced. Distribution of the different fungal genera was not homogeneous in the three locations (p<0.05), although Penicillium and Aspergillus were the most prevalent contaminants, regardless the geographic origin of the samples. Other genera, such as Eurotium, Fusarium, Phoma, Ulocladium, Mucor and Rhizopus were less frequently isolated. Absidia, Alternaria, Cladosporium, Dreschlera, Epicoccum and Monascus were sporadically encountered. Significant differences (p<0.05) in the distribution of fungal genera in samples with and without saponins from each location were observed. In all cases, processing caused a decrease of Aspergillus incidence, while increased the proportion of Penicillium, Eurotium, Mucor and Rhizopus indicating that these genera were part of the internal mycota. A. flavus and A. niger were the dominating species of genus Aspergillus. A similar pattern of prevalent Penicillium species was observed in samples with and without saponins, since P. aurantiogriseum, P.chrysogenum, P. citrinum and P. crustosum were always present in high number, although their relative density was variable according to the geographic origin of samples. Mycotoxin-producing ability of most representative species was also determined. Toxigenic strains of A. flavus (aflatoxins and cyclopiazonic acid), A. parasiticus (aflatoxins), P. citrinum (citrinin) and P. griseofulvum (cyclopiazonic acid) were found. None of the A. niger isolates was ochratoxin A producer. The above mentioned mycotoxins were not detected in the samples analyzed.     

Water-Based Graphene Oxide–Silicon Hybrid Nanofluids—Experimental and Theoretical Approach

In the current paper, a new hybrid nanofluid based on graphene oxide sheets and silicon nanoparticles is proposed for thermal applications. GO sheets and Si nanoparticles with different mixture ratios are dispersed in distilled water. Dynamic viscosity is measured at temperatures within the range 20–50 °C and the values are compared to the results available in the literature. The results indicated that the viscosity increases with increasing the mixture ratio of graphene oxide. A new correlation for the dynamic viscosity based on the experimental findings is proposed. Finally, the criteria for the performance of new hybrid nanofluid for thermal applications are analyzed.     

Annual anomalies and trends for TOMS reflectivities (1978–2005) in the Southern Hemisphere

Annual anomalies of Lambertian equivalent reflectivity (LER) retrieved from the total ozone mapping spectrometer spanning the period November 1978–November 2005 were studied in the Southern Hemisphere, in a region bounded by 0° S and 60° S, and their trends were estimated. With the exception of few regions where the variable may represent the contribution of both cloudiness and snow, trends in LER anomalies provided an evolution of total cloudiness. On average, the study region experienced a net increase in LER values of 0.78 reflectivity units (RU) decade^?1; if only significant trend values are considered this figure increased to 1.18 RU decade^?1. The region that showed the largest upward trend, up to 4 RU decade^?1, was located over the eastern Pacific, off the coasts of Chile and Peru, where the presence of marine stratocumulus is frequent. Despite the overall positive trend there were regions that yielded a negative one, most notably the tropical latitudes of South America and Africa. The yearly zonal means also showed a positive trend at all latitudes, but significance occurred beyond 20° S only. Correlation maps between LER anomalies and five different circulation indices were also introduced. The indices with the highest and lowest number of significant correlation values were the Madden–Julian oscillation at 70° E and the quasi-biennial Oscillation, respectively.     

Investigations on Sweet Cherry Phenolic Degradation During Thermal Treatment Based on Fluorescence Spectroscopy and Inactivation Kinetics

Five anthocyanins were detected in the sweet cherry extract as follows: cyanidin 3-rutinoside, cyanidin 3-glucoside, peonidin 3-rutinoside, peonidin 3-glucoside, and pelargonidin 3-rutinoside, whereas the cyanidin 3-rutinoside was found to be in the highest amount. The effect of thermal treatment on the degradation of the polyphenolic compounds in sweet cherry extract was investigated in the range of 70–120 °C by means of fluorescence spectroscopy and spectrophotometric techniques. The fluorescence spectra were dominated by emission bands with maximum ranging from 356 nm at 25 °C to 350 nm at 110 °C. The heating of sweet cherry extract resulted in structural changes that led to a significant decrease in fluorescence intensity when increasing temperature. Degradation rate constants were estimated using a fractional conversion kinetic model. The activation energy values revealed a higher-temperature dependence of antioxidant activity, followed by anthocyanins, total polyphenols, and total flavonoids.     

Effects of social exclusion in trauma survivors with posttraumatic stress disorder.

Trauma survivors with posttraumatic stress disorder (PTSD) often experience or report social stigmatization and isolation. Williams (2001) provided an experimental paradigm to assess behavioral effects of social exclusion. This paradigm (face-to-face version) has been applied in a 2 × 2 group × experimental condition design. Participants in the PTSD group (N = 16) and the nontraumatized control group (N = 25) were randomly assigned to an exclusion or inclusion condition. The results showed interaction effects for main psychopathological assessments (depression, anxiety, psychoticism) and expected main effects for the majority of outcome measures (psychopathology, well-being, belonging, and meaningful existence). The research concludes that a general assumption of elevated levels of self-perceived social exclusion in PTSD patients has to be considered in terms of differentiated psychopathological effects of exclusion. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Dietary intakes and food sources of fat and fatty acids in Guatemalan schoolchildren: A cross-sectional study

Background  

Consumption of healthy diets that contribute with adequate amounts of fat and fatty acids is needed for children. Among Guatemalan children, there is little information about fat intakes. Therefore, the present study sought to assess intakes of dietary fats and examine food sources of those fats in Guatemalan children.