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Grape juice and wines (Vitis sp.) are the products that are most produced and consumed from different varieties of grapes. About 20% of pomace is generated from processing but there are very few products available with added grape pomace. Consequently, the aim of this study was to characterize flours made from grape skin (GSF) and grape pomace (GPF: seeds + skin) from organic Vitis labrusca L. cv. Bordeaux with respect to physicochemical composition, bioactive compounds content and antioxidant/reducing capacities. The by-products presented a high content of insoluble fibers (55.84 ± 0.63 and 51.02 ± 1.12 g/100 g, respectively); total lipids contents below 10 g/100 g; and >1.900 mg gallic acid equivalent (GAE)/100 g total phenolic content, in which total ortho-diphenols, flavonols, anthocyanins and water-soluble condensed tannins were the main chemical compounds. Regarding the in vitro functionality, which was measured by chemical methods, the GPF and GSF presented values of 1373.64 ± 72.94 and 361.48 ± 2.99 mg GAE/100 g iron reducing capacity; 1574.26 ± 8.94 and 1499.79 ± 31.39 mg ascorbic acid equivalent/100 g in the reduction of DPPH radical; and 2892.46 ± 61.69 and 426.34 ± 18.85 mg of quercetin equivalent/100 g of total reducing capacity, respectively. The results indicate that the GPF and GSF produced from the organic grape juice industry are promising materials for use by food companies. [ABSTRACT FROM AUTHOR]

Unlabelled: Folin-Ciocalteu colorimetric assay (FC) is the most widely used assay to estimate the total phenolic content in foods, beverages, herbs and other plant extracts, but many chemical compounds may act as interfering agents, producing inaccurate estimations of the real concentration of phenolic compounds in the matrix. Based on this limitation, the objective of this study was to compare, quantitatively, the Folin-Ciocalteu and Prussian Blue (PB) assays in estimating the total phenolic content in purple grape juices (n = 20; Vitis labrusca L.) and teas (n = 25) from different botanical origins using 96-well microplates. PB assay presented a low limit of detection (PB = 0.27 mg/L; FC = 0.25 mg/L) and quantification (PB = 0.92 mg/L; FC = 0.82 mg/L), showing its suitability in screening the total phenolic content in grape juices and teas. FC and PB assays presented a high association (P < 0.0001) for teas (r = 0.887) and grape juices (r = 0.923). The advantages of PB over FC assay are its simplicity, low time consumption (15 min reaction as compared to 60 min reaction for the FC assay), lower usage of reagents (solutions are prepared in a mM base), and higher selectivity. Additionally, PB assay was proven to be reproducible and repeatable and, therefore, may be used as an alternative to FC assay., Practical Application: Prussian Blue assay (PB) has been used as an alternative to Folin-Ciocalteu assay (FC) to estimate the total content of phenolic compounds in herbs and some natural products. In our study we showed that the advantages of PB assay over FC are its simplicity, low time consumption (15 min reaction as compared to 60 min reaction for the FC assay), lower usage of reagents (solutions are prepared in a mM base) and higher selectivity as compared to FC assay. Additionally, PB assay was proven to be reproducible and repeatable and, therefore, may be used as an alternative to FC assay., (© 2015 Institute of Food Technologists®)

The objectives of this study were to characterize organic, biodynamic, and conventional purple grape juices (n = 31) produced in Europe based on instrumental taste profile, antioxidant activity, and some chemical markers and to propose a multivariate statistical model to analyze their quality and try to classify the samples from the 3 different crop systems. Results were subjected to ANOVA, correlation, and regression analysis, principal component analysis (PCA), hierarchical cluster analysis (HCA), soft independent modeling of class analogy (SIMCA), and partial least-squares discriminant analysis (PLSDA). No statistical significant differences (P > 0.05) were observed among juices from the 3 crop systems. Using PCA and HCA, no clear separation among crop systems was observed, corroborating the ANOVA data. However, PCA showed that the producing region highly affects the chemical composition, electronic tongue parameters, and bioactivity of grape juices. In this sense, when organic and biodynamic were grouped as "nonconventional" juices, SIMCA model was able to discriminate 12 out of 13 organic/biodynamic juices and 17 out of 18 conventional juices, presenting an efficiency of 93.5%, while 11 out of 13 non-conventional and 100% conventional grape juices were correctly classified using PLSDA. The use of electronic tongue and the determination of antioxidant properties and major phenolic compounds have shown to be a quick and accurate analytical approach to assess the quality of grape juices., (© 2014 Institute of Food Technologists®)

Background: Protein structure alignments are usually based on very different techniques to sequence alignments. We propose a method which treats sequence, structure and even combined sequence + structure in a single framework. Using a probabilistic approach, we calculate a similarity measure which can be applied to fragments containing only protein sequence, structure or both simultaneously., Results: Proof-of-concept results are given for the different problems. For sequence alignments, the methodology is no better than conventional methods. For structure alignments, the techniques are very fast, reliable and tolerant of a range of alignment parameters. Combined sequence and structure alignments may provide a more reliable alignment for pairs of proteins where pure structural alignments can be misled by repetitive elements or apparent symmetries., Conclusion: The probabilistic framework has an elegance in principle, merging sequence and structure descriptors into a single framework. It has a practical use in fast structural alignments and a potential use in finding those examples where sequence and structural similarities apparently disagree.