RESUMO A ressonância magnética nuclear (RMN) é uma técnica de espectroscopia amplamente utilizada pelos químicos e físicos para determinar a estrutura química de moléculas que foi adaptada para gerar imagens, conhecidas como tomografia por imagem de ressonância magnética nuclear (IRM), amplamente utilizada em diagnóstico médico. A importância da RMN na química, física, medicina, materiais e agricultura tem sido reconhecida por vários Prémios Nobel de Física, 1952, Química, 1991 e 2002, e Medicina em 2003. Portanto, a RMN pode ser aplicada para obter: i) imagens do corpo humano, animais e materiais; ii) espectros de alta resolução para obtenção de informações estruturais e dinâmicas de produtos químicos, materiais etc.; e iii) obter informações quantitativas e qualitativas da composição química de alimentos, produtos agrícolas, utilizando relaxometria de baixa resolução. A IRM e a RMN de alta resolução tem sido aplicadas em produtos agroalimentares, principalmente na pesquisa, uma vez que normalmente dependem de instrumentos caros de grandes dimensões, o que restringe a sua utilização em aplicações rotineiras. Sensores de RMN que têm sido utilizados com mais frequência em produtos agroalimentares baseiam-se em instrumentos de baixa resolução ou de baixo campo ou domínio de tempo TD-NMR. Esses instrumentos de baixo custo tem sido utilizados para análises qualitativas e quantitativas de produtos agroalimentares, como sementes e grãos intactos, frutas intactas, carnes, óleos e alimentos processados. Neste artigo, é apresentada uma revisão das técnicas de RMN, seus principais aspectos da instrumentação, e discutidas algumas aplicações de TD-RMN e IRM na análise não invasiva de alimentos, sementes e outros produtos agrícolas. (RMN IRM, , (IRM) médico física medicina Física 1952 Química 199 2002 2003 Portanto i humano ii etc. etc iii agrícolas pesquisa dimensões rotineiras baseiamse baseiam se TDNMR. TDNMR TD NMR. NMR TD-NMR intactos intactas carnes processados artigo instrumentação TDRMN (IRM 195 19 200 1 20 2

ABSTRACT Nuclear magnetic resonance (NMR) is a spectroscopy technique widely used by chemists and physicists to determine the chemical structure of molecules that was adapted to generate imaging, known as nuclear magnetic resonance imaging (MRI), which is widely used in medical diagnosis. The importance of NMR in chemistry, physics, medicine, materials, and agriculture has been recognized with several Nobel Prizes in Physics, 1952, Chemistry, 1991 and 2002, and Medicine in 2003. Therefore, NMR can be applied to obtain: i) imaging of the human body, animal and materials; ii) high-resolution spectra to obtain structural and dynamical information of chemicals, materials etc.; and iii) quantitative and qualitative information of chemical composition of products such as food and agricultural products, using low-resolution relaxometry. High-resolution NMR and MRI have been applied in agri-food products, mostly as a research tool as they typically rely on expensive and bulk instruments, which restrict their uses in routine applications. The NMR sensors that have been more frequently used in agri-food products are based on low-resolution or low-field or time-domain NMR (TD-NMR) instruments. These low-cost instruments have been used for qualitative and quantitative analysis of agri-food products such as intact seeds and grains, intact fruits, meat, oils, and processed foods. In this paper, an overview of the NMR techniques and its main instrumentation aspects are presented, and some applications of TD-NMR and MRI in the non-invasive analysis of food, seeds, and others agricultural products are discussed. (NMR MRI, , (MRI) diagnosis chemistry physics medicine Physics 1952 Chemistry 199 2002 2003 Therefore i body ii highresolution high resolution chemicals etc. etc iii lowresolution low relaxometry Highresolution High agrifood agri lowfield field timedomain time domain TDNMR TD (TD-NMR lowcost cost grains fruits meat oils foods paper presented noninvasive non invasive discussed (MRI 195 19 200 1 20 2

Citrus sudden death (CSD) is a disease that has affected millions of orange trees in Brazil, leading to economic losses in the order of billions of US dollars. This article examines the effects of CSD on the fatty acid composition of triacylglycerides (TAG) extracted from rootstock and scion bark. The fatty acid profile determined by gas chromatography showed a reduction in oleic and linolenic acids, and an increase in the saturated fatty acids and linoleic acid content, which was in line with the severity of CSD. The reduction in linolenic acid content was related to its role in the biosynthesis of jasmonic acid, which is involved in responses to abiotic and biotic stresses, as well as senescence. These alterations in the fatty acid profile were also used to classify plants both with and without CSD symptoms by using chemometric means. This method represents an alternative to support the diagnosis of CSD disease.

Low field time-domain nuclear magnetic resonance (TD-NMR) relaxometry of paramagnetic metal cations (PMC) has been widely used to study and improve contrast agents for magnetic resonance imaging (MRI). However, despite its remarkable potential, TD-NMR is rarely used to study PMC complexes, and coordination compounds in non-biomedical application. Therefore, this review aimed to provide comprehensive information not only to non-nuclear magnetic resonance (NMR) relaxation specialists, but also to scientists from distinct levels and expertise, as a way to pave the path for modern analytical and research of PMC complexes. Some fundamental concepts about NMR, paramagnetic relaxation mechanism, as well as traditional and modern methods to measure the longitudinal (T1) and transverse (T2) relaxation times constants are addressed. Here, we address some applications in analytical, electrochemical, and inorganic chemistry, electrodeposition reactions, as well as studies on PMC complexes and coordination compounds in solution.

This work reports the synthesis, structure and catalytic activity of a novel ruthenium(II) complex, [RuCl(dppb)(44bipy)(4-pic)]PF6 (where dppb = 1,4-bis(diphenylphosphine)butane; 44bipy = 4,4’-dimethyl-2,2’-dipyridyl; 4-pic = 4-picoline). The molecular structure and catalytic activity were studied by Fourier transform infrared (FTIR), UV-Vis and nuclear magnetic resonance (NMR) spectroscopies, cyclic voltammetry, and X-ray crystallography, while the electronic structure was investigated by density-functional theory (DFT) and time dependent DFT (TD-DFT) methods. Electrochemical studies showed the substitution of the chlorido ligand from the precursor by the 4-pic ligand, exhibiting the RuII/RuIII process at 1.21 V. The structure of the compound was optimized using DFT simulations and showed data similar to the X-ray structure. The UV-Vis absorption spectrum showed a good agreement with TD-DFT simulations. The highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO) energies were determined at the Becke, 3-parameter, Lee-Yang-Parr (B3LYP) level. The study of the catalytic activity in the transfer hydrogenation of ketones by the 1H NMR showed efficient transfer hydrogenation reaction at 60 ºC, employing acetophenone as substrate and resulting in a high conversion. The formation of two ruthenium-hydride species was observed.

Growth in the international popularity of Brazil nuts oil (Bertholletia excelsa, Bonpl.) has demanded a closer look at quality aspects of the nuts. In this context, time-domain 1H nuclear magnetic resonance spectroscopy (TD-NMR) can be a useful tool for assessing the lipid portion of such matrices. In this work, a TD-NMR method was developed and validated to assess the oil content directly from Brazil nuts following the ISO 10565:1998 and DOQ-CGCRE-008. Full validation was addressed covering the working range from 0.67 to 25.00 g (coefficient of determination, R2= 0.9993). Limits of detection (LOD) and quantification (LOQ) were 0.20 and 0.67 g, respectively. The repeatability and intermediate precision assays met the guide requirements. Oil contents obtained in two laboratories (different equipment) were statistically similar (66.93 ± 4.69 and 70.13 ± 4.15%), highlighting the method’s robustness. The developed approach has the potential to be adopted as an industrial reference method for in situ monitoring of Brazil nuts oil contents.

Abstract BRS 425 is a high-oleic runner peanut cultivar related to wild ancestral parents, partially resistant to early and late leaf spot and spotted wilt. It is large-seeded and contains 46% oil. BRS 425 is adapted to the main peanut-producing regions of Brazil.

Conjugated linoleic acid (CLA), a fatty acid found in ruminant food products, has been associated with anticarcinogenic activity. However, its effect on cancer metabolism is unclear. In this paper we evaluated the effects of cis-9, trans-11 CLA on the metabolic profile of MCF-7 and MDA-MB-231 breast cancer cells using high-resolution magic angle spinning (HR-MAS) nuclear magnetic resonance (NMR) spectroscopy. The NMR spectra showed that phosphocholine level, a cancer malignance biomarker, was reduced in both cells treated with CLA, but the reduction was more pronounced in MCF-7 cells. The NMR spectra also showed that CLA has opposite effect on MCF-7 and MDA-MB-231 acetone metabolism. Acetone signal has been observed in the spectra of MDA-MB-231 control cells, but not in the spectra of the cells treated with 50 and 100 µM CLA. Conversely, the acetone signal is very small or not observed in the NMR spectra of MCF-7 control cells and in cells treated with 50 µM of CLA, but is very strong in the spectra of the cells treated with 100 µM of CLA. Therefore, this CLA concentration is causing a ketosis in MCF-7 cells by inducing the use of fatty acids as an energy source or by reducing acetone catabolism. These results indicate that CLA interfere in the metabolism of both cells. However, the strongest effect has been observed on the metabolism of MCF-7 cells cultivated in the presence of 100 µM CLA. Therefore, CLA could be a potential anticarcinogenic drug, especially for cells with positive estrogen receptor, such as MCF-7.

Moderate supplementation with extract of mate to a standard broiler diet in feeding experiment with 5 treatment groups was found to increase production of endogenous antioxidants in muscles, improving meat quality and storage stability. For addition of 250 or 500 mg extract per kg feed, pre-cooked meatballs made from the breast muscles had a significant lower level of secondary lipid oxidation products during one week of chill storage. Addition of 750 or 1000 mg extract per kg feed had an increasing prooxidative effect during storage of the meatballs. For the moderate levels of plant phenols in feed, a metabolic study based on nuclear magnetic resonance (NMR) spectroscopy of meat extracts showed that mate extract added to the feed increased the muscle level of antioxidative peptides like anserine, while indication of toxic effects was noted for the higher levels of feed additives. Rate of formation of radicals as detected by electron paramagnetic resonance (EPR) spectroscopy was found to correlate with the oxidative damage and a kinetic analysis demonstrated that the antioxidative effect of mate supplemented to the feed could be assigned to radical scavengers present in the meat. These findings for the monogastric animals are different from results previously obtained for ruminants, where plant phenols rather seem to affect the microflora of the digestive tract.

Zeínas são proteínas de reserva do milho (prolaminas), que podem ser extraídas através de solubilização em meio alcoólico. Essas proteínas são altamente hidrofóbicas, com elevado grau de polimerização. Neste estudo, zeínas do tipo a (massa molecular entre 10 e 22 kDa) foram extraídas do glúten do milho e caracterizadas com respeito às suas principais bandas de absorção espectroscópica na região do infravermelho. Blendas de zeínas com ácido oléico (AO) como plastificante foram avaliadas em diversas proporções e filmes processados por casting sobre superfície apolar. Filmes de zeínas sem plastificante mostraram-se inviáveis para manipulação e medidas, mas a adição de 1 e 2% em massa de AO proporcionou um significativo aumento do módulo de elasticidade, segundo análise realizada por DMA. A presença de plastificante introduz também irregularidades superficiais e leva a uma perda das características hidrofóbicas dessas proteínas.

Zeins comprise a group of maize storage proteins (prolamines) that can be extracted via solubization in alcoholic media. Such proteins are highly hydrophobic with elevated degree of polymerization. In the present study, zein type a (molecular mass between 19 and 22 kDa) was extracted from corn gluten meal and characterized concerning the main spectroscopy absorption bands in the infrared region. Cast films were processed by blending zein and oleic acid (OA) as plasticizer. Films with no plasticizer were extremely brittle, and thus impossible to handle or used for mechanical analysis. The addition of 1 or 2% wt OA resulted in significant increase in the elongation length, according to DMA analysis. The presence of the plasticizer led to microscopic surface irregularities and to a reduction in the original hydrophobic characteristics.

The FTIR spectroscopy has been used to quantify the secondary structures of proteins, using amide I band (1600 - 1700 cm-1). The resolution enhancement methods have been used to resolve the individual components of this band that correlate to the secondary structure. In this paper we discuss the methods of derivative, Fourier deconvolution and fitting with simulated spectra. The results shows that they have serious problems and can be used only as a qualitative or semiquatitative method.

As técnicas de microscopia de varredura por força tem promovido um grande impacto em ciência dos materiais devido a possibilidade de obtenção de imagens em escala que pode chegar no nível atômico. Neste trabalho serão apresentados o princípio básico de funcionamento da microscopia de varredura por força, os vários modos de operação e as forças envolvidas e medidas. O potencial de aplicação destas técnicas no estudo de materiais, e em particular de polímeros, serão discutidos. Uma comparação da microscopia de força atômica com outras técnicas de microscopia será apresentada, assim como exemplos da utilização da técnica de microscopia de força atômica para o estudo de polímeros.

The scanning force microscopy techniques are promoting a great impact on materials science due to the possibility to obtain images down to the atomic scale. This work reports on the basic principles of the scanning force microscopes, their operation modes and the forces involved and measured. The potential application of these techniques on the study of materials, particularly on polymers, is discussed. A comparison of atomic force microscopy - AFM - with other techniques is presented, as well as some examples of the use of AFM on the study of polymers.