RESUMO As embalagens têm como função básica proteger o alimento e garantir a sua integridade comercial. Podem ser produzidas a partir de materiais biodegradáveis com funcionalidades específicas, tais como ação antimicrobiana e antioxidante. Além disso, pesquisas vêm sendo desenvolvidas de modo a substituir os aditivos sintéticos por outros naturais, como os extratos vegetais, devido aos compostos químicos presentes em suas misturas. O poli(butileno adipato co-tereftalato) - (PBAT) vem sendo extensivamente estudado como uma possível substituição aos polímeros convencionais devido à sua biodegradabilidade. Desse modo, o objetivo desse trabalho foi avaliar as potencialidades dos extratos vegetais de jurema preta (Mimosa tenuiflora) e cajueiro (Anacardium occidentale Linn), a fim de aplicá-los como aditivos em embalagens de PBAT com propriedades ativas antioxidantes e antimicrobianas. Os extratos foram obtidos pela técnica de extração Sohxlet em três diferentes tempos, 4, 6 e 8 horas, cujo melhor rendimento ocorreu nos tempos de 6 horas para jurema preta e 4 horas para cajueiro. No teste de presença de flavonóides o extrato de jurema preta apresentou maior concentração e no teste de fenólicos totais, utilizando o método de Folin-Ciocalteau, o cajueiro obteve maior concentração. Ambos os extratos apresentaram capacidades antioxidantes significativas pelos dois métodos, fosfomolibdênio e DPPH. cajueiro apresentou melhor halo de inibição frente ao Staphylococcus aureus, e, por isso, foi determinada a sua concentração mínima inibitória (CMI), 0,0170 g.mL-1. Esse extrato foi incorporado ao PBAT, para o ensaio de migração no meio etanólico, por meio do qual foi determinado um modelo cinético e foi observado que a taxa de migração, 0,0167 ?g.mL-1.min-1, foi reduzida em cerca de um dia, indicando bom potencial do extrato para esses tipos de embalagem.

ABSTRACT Packaging has the basic function of protecting the food and ensuring its commercial integrity. They can be produced from biodegradable materials with specific functionalities such as antimicrobial and antioxidant action. In addition, research has been carried out to replace synthetic additives with natural additives, such as plant extracts, due to the chemical compounds present in their mixtures. Poly (butylene adipate co-terephthalate) - (PBAT) has been extensively studied as a possible replacement for conventional polymers due to its biodegradability. Thus, the objective of this work was to evaluate the potentialities of jurema preta (Mimosa tenuiflora) and cajueiro (Anacardium occidentale Linn) plant extracts in order to apply them as additives in PBAT packages with antioxidant and antimicrobial active properties. The extracts were obtained by the Sohxlet extraction technique at three different times, 4, 6 and 8 hours, with the best yield at 6 hours for jurema preta and 4 hours for cajueiro. In the flavonoid presence test the jurema preta extract presented higher concentration and in the total phenolics test, using the Folin-Ciocalteau method, the cashew tree obtained the highest concentration. Both extracts showed significant antioxidant capacities by the two methods, phosphomolybdenum and DPPH. Cashew tree presented better inhibition halo against Staphylococcus aureus, and therefore its minimum inhibitory concentration (MIC) was determined, 0.0170 g.mL-1. This extract was incorporated into the PBAT for the ethanolic migration test, by means of which a kinetic model was determined and it was observed that the migration rate, 0.0167 ?g.mL-1.min-1, was reduced by about a day, indicating good extract potential for these types of packaging.

Abstract In this work were developed and evaluated new antimicrobial films of polyhydroxybutyrate (PHB) additivated with polyethyleneglycol (PEG) and clove essential oil (CEO). The PHB/PEG/CEO films were prepared using the solution casting technique. The CEO concentrations varied between 0.0 and 15% (w/w), related to the total mass (1.4 g), without considering the solvent used. The CG-MS analysis showed that the major component of the CEO was eugenol (72.96%). The antimicrobial activity from the CEO was evaluated against three bacteria (E. coli, E. aerogenes and S. aureus). The migration of CEO in the films occurred with all tested simulants. Thermal analysis has shown that the addition of 15% w/w of the CEO causes the biggest changes in the chemical structure of the material, resulting in less energy during film processing. The mechanical data demonstrated that the addition of 15% w/w of the CEO results in more flexible films.

The measurement of nuclear magnetic resonance parameters in an anisotropic media, such as residual dipolar coupling (RDC), has proven to be an excellent methodology for the refinement of chemical structures, being used as a complementary tool in the determination of the relative configuration, conformation, and constitution of organic compounds. In this study, we applied this methodology to determine the relative configuration of α-santonin, a natural product with four stereocenters, while assigning its prochiral methylene protons using only the RDCs obtained in a polyacrylonitrile polymer gel swollen in DMSO-d6.

The ¹H NMR data set of a series of 3-aryl (1,2,4)-oxadiazol-5-carbohydrazide benzylidene derivatives synthesized in our group was analyzed using the chemometric technique of principal component analysis (PCA). Using the original ¹H NMR data PCA allowed identifying some misassignments of the proton aromatic chemical shifts. As a consequence of this multivariate analysis, nuclear Overhauser difference experiments were performed to investigate the ambiguity of other assignments of the ortho and meta aromatic hydrogens for the compound with the bromine substituent. The effect of the 1,2,4-oxadiazol group as an electron acceptor, mainly for the hydrogens 12,13, has been highlighted.

A reação de tri-O-acetil-D-glucal (1) com cicloexanol (2) usando o método de Ferrier forneceu o glicosídeo cicloexílico insaturado 3, que por sua vez produziu o composto 12 através da seqüência envolvendo hidrólise, tritilação seletiva no oxigênio do C-6, oxidação alílica e cicloadição dipolar 1,3 com diazometano. O produto 17 foi obtido em quatro etapas a partir de 6. Cálculos semi-empíricos de orbitais moleculares (AM1) para o composto 12 forneceram a conformação estável e também apoiaram a existência do efeito anomérico. Foi feito um esforço para abrir o anel pirazolínico dos compostos 12 e 17, porém não tivemos sucesso. A carga negativa parcial no C-3 foi responsável pela falta de reatividade deste carbono frente a redução da ligação C=N.

Reaction of tri-O-acetyl-D-glucal (1) with cyclohexanol (2) using Ferrier's method provided the unsaturated cyclohexyl glucoside 3, which furnished the title compound 12 in a sequence involving hydrolysis, selective tritylation of oxygen at C-6, allylic oxidation with MnO2 and 1,3-dipolar cycloaddition with diazomethane. Starting from 6, product 17 was obtained in four steps. Semi-empirical molecular orbital calculations (AM1) were carried out for compound 12 which gave an idea about its stable conformation, and also supported the existence of the anomeric effect. Attempts to open the pyrazoline ring in 12 and 17 failed. Partial negative charge at C-3 was responsible for the lack of reactivity of 12 towards reduction of C=N bond.