in vitro preliminary evidences on the antioxidant properties of biogenic amines

Antioxidant properties of the principal biogenic amines were determined in vitro by four analytical methods—Folin Ciocalteu, DPPH, enzymatic and inhibition of lipid peroxidation—in order to avoid possible measuring-method linked mistakes. Different results are obtained, depending on the parameters that each of them measures. The combination of the data indicates that all examined amines show antioxidant characteristics: in particular, tyramine, serotonin, L-norepinephrine, (-)-epinephrine and dopamine owing to their (poly)phenolic structure too, while aliphatic polyamines-spermine, spermidine, putrescine and cadaverine-histamine, melatonin and tryptamine appear to act specifically on the oxygen-consuming species involved in the lipid peroxidation of polyunsaturated fatty acids

Effect of the combined application of heat treatment and proteases on protein stability and volatile composition of Greek white wines

Aim: This work evaluates the effects of the combined use of heat treatment (HT, 75 °C, 2 min) and proteases (P) on the protein stability and volatile composition of two white wines, obtained from the Greek cv. Assyrtiko and Moschofilero.Methods and results: Wine protein stabilization was assessed by heat test, using RP-HPLC determination of pathogenesis-related proteins (PRP) and by sodium dodecyl-sulfate polyacrylamide gel electrophoresis (SDS-PAGE). The impact of bentonite and P + HT treatment on wine aroma profile was evaluated by GC-MS with liquid–liquid extraction. According to the heat test, in Assyrtiko wine the level of stability achieved with P + HT was comparable with that obtained by bentonite fining and for Moschofilero wine – where protein instability was higher – bentonite was more efficient. RP-HPLC profiles showed that, in general, higher percentages of chitinases (CH) than thaumatin-like proteins (TLP) were removed by both bentonite and P + HT, with a similar efficiency for the two treatments and sometimes better performances for the latter. Conversely, TLP were removed more efficiently by bentonite, even if some fractions were eliminated to a slightly higher extent by proteases. In the conditions of the experiment, bentonite resulted in minor changes to the wine aroma profile. However, heating during protease treatment modified wine volatile composition, reducing the concentration of esters produced during fermentation while simultaneously increasing the contents of certain esters characteristic of aging such as ethyl lactate.Conclusions: The combination of proteases and heat treatment may be a promising technique for protein stabilization of wines. However, further investigations are needed to optimize the time:temperature ratio of the heat treatment in order to obtain the maximum protease activity and the minimum thermal deterioration of the wine quality.Significance and impact of the study: The results of this study have a practical interest for both the scientific community and wine sector, contributing to knowledge of the efficacy and limitations of the use of protease enzymes for wine stabilization

Plasma Activation of Copper Nanowires Arrays for Electrocatalytic Sensing of Nitrate in Food and Water

Electrochemical methods for nitrate detection are very attractive since they are suitable for in-field and decentralized monitoring. Copper electrodes are often used to this aim as this metal presents interesting electrocatalytic properties towards nitrate reduction. In this research, we study improvements in the electrochemical analysis of nitrate in natural water and food by taking advantage of the detection capabilities of ensembles of copper nanowire electrodes (CuWNEEs). These electrodes are prepared via template electrodeposition of copper within the nanopores of track-etched polycarbonate (PC) membranes. A critical step in the preparation of these sensors is the removal of the template. Here, we applied the combination of chemical etching with atmospheric plasma cleaning which proved suitable for improving the performance of the nanostructured copper electrode. Analytical results obtained with the CuWNEE sensor for nitrate analyses in river water samples compare satisfactorily with those achieved by standard chromatographic or spectroscopic methods. Experimental results concerning the application of the CuWNEEs for nitrate analysis in food samples are also presented and discussed, with focus on nitrate detection in leafy vegetables

Antioxidant properties and chemical composition relationship of Europeans and Brazilians propolis

The antioxidant activity of ethanol extracts of propolis, bee glue, of various climate and orographic characteristics, col- lected from Italy, Brazil and Russia, was evaluated measuring their inhibitory action on peroxidation of linoleic acid, radical scavenging ability towards 2,2’-diphenyl-1-picrylhydrazyl, total phenolic content and reducing capacity by en- zymatic and Folin method respectively. Propolis samples were chemically characterized by HPLC-MS/MS in order to find a possible correlation between antioxidant activity and polyphenols composition and quantification. The results obtained indicate that Italian and Russian propolis samples have similar polyphenolic composition and, as a consequence, almost similar antioxidant activity, while Brazilian propolis evidence lower polyphenolic and antioxidant characteristics. Climate and orography reasons of these differences are also suggested

Moral and cognitive refractions : contributions of durkheimian sociology to comprehending 2018 Brazilian presidential elections

O desafio proposto por este dossiê sobre a atualidade dos clássicos nas ciências sociais nos encorajou a produção de um ensaio coletivo no qual mobilizamos conceitos fundamentais oriundos da teoria de Émile Durkheim para compreender alguns aspectos do segundo turno das eleições presidenciais brasileiras de 2018. Para tanto, partimos da ideia das categorias e representações coletivas como mediações socialmente construídas de nossa relação com o mundo e, em seguida, indicamos as categorias de sagrado e profano como particularmente relevantes para o estabelecimento da estrutura e da dinâmica social. Ao final, procuramos indicar como essas noções basilares podem dialogar com a teoria da ação e a sociologia compreensiva de Weber, resultando na proposta de uma tipologia da escolha do voto, com o intuito de elucidar um fenômeno candente durante esse processo, qual seja, o do espanto diante de escolha radicalmente oposta por parte de pessoas próximas.The challenge posed by this dossier about the actuality of classics in social sciences encouraged us to write a collective essay in which we articulate fundamental concepts from Émile Durkheim’s theory to understand some aspects of the second turn of 2018 Brazilian presidential elections. To achieve it, we start from the idea of categories and collective representations as socially constructed mediations of our relationship with the world, and then, we indicate the sacred and profane categories as particularly relevant to the establishment of social structure and dynamic. In the end, we intend to indicate how our basic notions can dialogue with Weber’s theory of action and comprehensive sociology, resulting on the proposition of a typology of vote choice, in the hopes of elucidating a candent phenomenon along this process, which is, the shock before a radically opposite choice made by close people

Antioxidant properties of resveratrol and piceid on lipid peroxidation in micelles and monolamellar liposomes.

The antioxidant activities of trans-resveratrol (trans-3,5,4′-trihydroxystilbene) and trans-piceid (trans-5,4′- dihydroxystilbene-3-O-β-D-glucopyranoside), its more widespread glycosilate derivative, have been compared measuring their inhibitory action on peroxidation of linoleic acid (LA) and the radical scavenging ability towards different free radicals (such as DPPH) and radical initiators. It has been found that the two stilbenes have similar antioxidant capacity, while the comparison with BHT (2,6-di-tert-butyl-4-methylphenol) and α-tocopherol (vitamin E, vit. E), taken as reference, points out a slower but prolonged protective action against lipid peroxidation. Furthermore, piceid appears more efficacious than resveratrol as a consequence of the reaction of the latter with its radical form. The DSC profiles of phosphatidylcholine liposomes of various chain lengths, and EPR measurements of spin labelled liposomes demonstrated that the susceptible hydroxyl group of these compounds are located in the\ud lipid region of the bilayer close to the double bonds of polyunsatured fatty acids, making these stilbenes particularly suitable for the prevention and control of the lipid peroxidation of the membranes

Effect of Peptide Ligands on the Quantized Charging Behavior of Monolayer-Protected Au38 Clusters

Gold nanoparticles protected by a monolayer of organothiolate molecules, with average formula Au38(S(CH2)2Ph)24, were synthesized and then subjected to ligand place exchange with peptide thiols to make nanoparticles with mixed monolayers. Investigation of the quantized charging behavior of these nanoparticles by electrochemical methods reveals that the spacing of two central oxidation peaks and, particularly, the peak position depend on the concentration of peptide in the monolayer