Evaluation of healthy and sensory indexes of sweetened beverages using an electronic tongue

Overconsumption of sugar-sweetened beverages may increase the risk of health problems and so, the evaluation of their glycemic load and fructose-intolerance level is essential since it may allow establishing possible relations between physiologic effects of sugar-rich beverages and health. In this work, an electronic tongue was used to accurately classify beverages according to glycemic load (low, medium or high load) as well to their adequacy for people suffering from fructose malabsorption syndrome (tolerable or not): 100% of correct classifications (leave-one-out cross-validation) using linear discriminant models based on potentiomentric signals selected by a meta-heuristic simulated annealing algorithm. These results may be partially explained by the electronic tongue’s capability to mimic the human sweetness perception and total acid flavor of beverages, which can be related with glycemic load and fructose-intolerance index. Finally, the E-tongue was also applied to quantify, accurately, healthy and sensory indexes using multiple linear regression models (leave-one-out cross-validation: R_adj > 0.99) in the following dynamic ranges: 4.7 < glycemic load ≤ 30; 0.4 < fructose intolerance index ≤ 1.5; 32 < sweetness perception < 155; 1.3 < total acid flavor, g L⁻¹ < 8.3; and, 5.8 < well-balanced flavor ≤ 74. So, the proposed electronic tongue could be used as a practical, fast, low-cost and green tool for beverage’s healthy and sensory evaluation.     

New Acetogenins from the Seeds of Annona coriacea

From the hexane and MeOH extracts of Annona coriacea Mart . (Annonaceae) seeds, two novel acetogenins, coriapentocins A and B ( 1 and 2 , resp.) were isolated. The known acetogenin bullacin ( 3 ) was also isolated from the hexane extract. The structures of compounds 1 – 3 were elucidated by NMR and MS analysis, and relative configurations were established by comparison with literature data.     

Environmentally friendly homocoupling reaction of functionalized potassium aryl trifluoroborates salts in aqueous media

The homocoupling reaction between potassium aryl trifluoroborates containing different functionalities promoted by a catalytic amount of Pd(OAc)₂ is described. The methodology uses water as a solvent under aerobic conditions to give the corresponding biaryl compounds in good yields.     

Temperature dependent Raman scattering study of l-ascorbic acid

Temperature dependent Raman study of l-ascorbic acid has been performed from 15 to 418 K. Changes in the wavenumber vs. temperature plots for some internal modes were interpreted as conformational molecular change and the discontinuity in the wavenumber vs. temperature plots along with the appearance of a new vibrational mode in the temperature range 200-270 K suggests that l-ascorbic acid undergoes a structural phase transition. For temperatures higher than 300 K, no relevant modification was observed on the Raman spectra thus indicating a stable structure at high temperatures. Additionally, a correlation between OH stretching wavenumber and the behavior of hydrogen bond is also made.     

Performance of a non-grafted monolithic support for purification of supercoiled plasmid DNA

The use of therapeutics based on plasmid DNA (pDNA) relies on procedures that efficiently produce and purify the supercoiled (sc) plasmid isoform. Several chromatographic methods have been applied for the sc plasmid purification, but with most of them it is not possible to obtain the required purity degree and the majority of the supports used present low capacity to bind the plasmid molecules. However, the chromatographic monolithic supports are an interesting alternative to conventional supports due to their excellent mass transfer properties and their high binding capacity for pDNA. The separation of pDNA isoforms, using short non-grafted monolithic column with CarbonylDiImidazole (CDI) functional groups, is described in the current work. The effect of different flow rates on plasmid isoforms separation was also verified. Several breakthrough experiments were designed to study the effect of different parameters such as pDNA topology and concentration as well as flow rate on the monolithic support binding capacity. One of the most striking results is related to the specific recognition of the sc isoform by this CDI monolith, without flow rate dependence. Additionally, the binding capacity has been found to be significantly higher for sc plasmid, probably because of its compact structure, being also improved when using feedstock with increased plasmid concentrations and decreased linear velocity. In fact, this new monolithic support arises as a powerful instrument on the sc pDNA purification for further clinical applications.     

Analysis of natural red dyes (cochineal) in textiles of historical importance using HPLC and multivariate data analysis

A new analytical approach based on high-performance liquid chromatography with diode array detector (HPLC-DAD) and multivariate data analysis was applied and assessed for analyzing the red dye extracted from cochineal insects, used in precious historical textiles. The most widely used method of analysis involves quantification of specific minor compounds (markers), using HPLC-DAD. However, variation in the cochineal markers concentration, use of aggressive dye extraction methods and poor resolution of HPLC chromatograms can compromise the identification of the precise insect species used in the textiles. In this study, a soft extraction method combined with a new dye recovery treatment was developed, capable of yielding HPLC chromatograms with good resolution, for the first time, for historical cochineal-dyed textiles. After principal components analysis (PCA) and mass spectrometry (MS), it was possible to identify the cochineal species used in these textiles, in contrast to the accepted method of analysis. In order to compare both methodologies, 7 cochineal species and 63 historical cochineal insect specimens were analyzed using the two approaches, and then compared with the results for 15 historical textiles in order to assess their applicability to real complex samples. The methodology developed here was shown to provide more accurate and consistent information than the traditional method. Almost all of the historical textiles were dyed with Porphyrophora sp. insects. These results emphasize the importance of adopting the proposed methodology for future research on cochineal (and related red dyes). Mild extraction methods and HPLC-DAD/MSⁿ analysis yield distinctive profiles, which, in combination with a PCA reference database, are a powerful tool for identifying red insect dyes.     

The Gauss�CKronecker curvature of minimal hypersurfaces in four-dimensional space forms

Let ${{\mathbb{Q}^4}(c)}$ be a four-dimensional space form of constant curvature c. In this paper we show that the infimum of the absolute value of the Gauss?CKronecker curvature of a complete minimal hypersurface in ${\mathbb{Q}^4(c), c\leq 0}$ , whose Ricci curvature is bounded from below, is equal to zero. Further, we study the connected minimal hypersurfaces M ³ of a space form ${{\mathbb{Q}^4}(c)}$ with constant Gauss?CKronecker curvature K. For the case c ?? 0, we prove, by a local argument, that if K is constant, then K must be equal to zero. We also present a classification of complete minimal hypersurfaces of ${\mathbb{Q}^4(c)}$ with K constant.     

Biomolecule profiles in inedible wild mushrooms with antioxidant value

The use of natural products isolated from mushrooms, included inedible species, against infection, cancer diseases and other oxidative-stress related diseases is one of the cornerstones of modern medicine. In the present work, the antioxidant molecule profiles of inedible mushroom species were evaluated and compared with those of edible species. The order of antioxidant abundance found in inedible wild mushrooms was: phenolics > flavonoids > ascorbic acid > tocopherols > carotenoids, similar to that of edible species. Furthermore the same energetic biomolecules were found including the disaccharide trehalose, the monosaccharide alcohol derivative mannitol and the fatty acids palmitic, oleic and linoleic acids. Fomitopsis pinicola revealed a very high phenolics concentration (388 mg GAE/g extract) and powerful antioxidant properties, mainly reducing power (EC??) value 60 μg/mL similar to the standard Trolox?). It could find applications in the prevention of free radical-related diseases as a source of bioactive compounds.     

Casbane diterpene as a promising natural antimicrobial agent against biofilm-associated infections

Croton nepetaefolius is a native plant from northeastern Brazil that belongs to the Euphorbiaceae family. The biological action of this plant has been extensively explored, being the secondary metabolites responsible for its properties alkaloids, diterpenes, and triterpenes. This study aimed to evaluate the ability of casbane diterpene (CD), isolated from the ethanolic extract of C. nepetaefolius, to inhibit microbial growth and biofilm formation of several clinical relevant species (bacteria and yeasts). It was found that CD possessed biocidal and biostatic activity against the majority of the species screened, with minimal active concentrations ranging between 125 and 500 μg/mL. In addition, it was observed that biofilm formation was inhibited even when the planktonic growth was not significantly affected. In conclusion, CD showed potential to be a natural tool for the treatment of diseases caused by different infectious microorganisms.