The present study reports a physicochemical comparison of shade-grown and sun-grown coffee beans, under unripe, rip and roasted-ripe conditions, using electrical conductivity measurements, electron paramagnetic resonance (EPR), infrared spectroscopy (FTIR), and high performance liquid chromatography (HPLC). Moreover, the assessed physicochemical parameters were compared with organoleptic evaluations based on the Coffee Quality Institute protocol. The values found for electrical conductivity, leached potassium, and stable free radicals were respectively 29%, 31%, and 350% higher for shade-grown coffee beans, whereas polyphenol oxidase enzymatic activity was 23% lower. By contrast, FTIR and HPLC measurements identified higher chlorogenic acid and lipid contents in sun-grown coffee beans. Importantly, the sensorial grade attributed to roasted-ripe grains was 12% higher for sun-grown coffee. Our findings suggest that shade-grown coffee beans have undergone microorganismal activity and undesired fermentation during cultivation, which resulted in lower coffee quality. A correlation between a set of selected physicochemical properties and organoleptic properties was robustly
Magnetic properties of sputtered Gd thin films grown on Si (100) substrates kept at two different temperatures were investigated using X-ray diffraction, ac magnetic susceptibility, and dc magnetization measurements. The obtained Gd thin films have a mixture of hcp and fcc structures, but with their fractions depending on the substrate temperature TS and film thickness x. Gd fcc samples were obtained when TS = 763 K and x = 10 nm, while the hcp structure was stabilized for lower TS (300 K) and thicker film (20 nm). The fcc structure is formed on the Ta buffer layer, while the hcp phase grows on the fcc Gd layer as a consequence of the lattice relaxation process. Spin reorientation phenomenon, commonly found in bulk Gd species, was also observed in the hcp Gd thin film. This phenomenon is assumed to cause the magnetization anomalous increase observed below 50 K in stressed Gd films. Magnetic properties of fcc Gd thin films are: Curie temperature above 300 K, saturation magnetization value of about 175 emu/cm3, and coercive field of about 100 Oe at 300 K; features that allow us to classify Gd thin films, with fcc structure, as a soft ferromagnetic material.
This study reports on physicochemical properties (total soluble solids, titratable acidity plus caffeine, trigonelline, 5-CQA, and total phenols contents) of five genotypes of Robusta coffee beans; Bamburral, Beira Rio, Clementino, Coringa, and Pirata. Green bean of Clementino presents the highest concentration of total soluble solids in dry basis (18.0%) and the lowest titratable acidity (154.0 mL-NaOH). Moreover, green beans of Clementino and Pirata show intermediate values of caffeine and trigonelline contents while presenting the highest yield index ofstable free radical formation after roasting, respectively equal to 26 and 23 (electron paramagnetic resonance-EPR data), and the highest content of 5-CQA (around 42 mg/g). Green beans of Bamburral, Beira Rio and Coringa show the highest concentration of total phenols (53 -56 mg/g), meaning the highest antioxidant activities (IC50 test) but reduced yield index of formation of stable free radicals after roasting, respectively equal to 13.0, 5.9, and 13.0 (EPR data).
In this article a bibliometric analysis of spinel ferrite production was carried out, with the purpose of to expanding the knowledge management on the research area, also identify future perspectives turned to the application of such structures and light to dry research. The study was designed based on a statistical and qualitative analysis of Web of Science (WoS) database documents from 1995-2017, using as an additional tool the CiteSpace software, which allows the expansion of the domain of knowledge on the subject With the acquirement of a set of bibliographic records of relevant publications, with subsequent identification of interlinked research groups (clusters). The CiteSpace software provides a set of empirical parameters, among them the so-called Betweenness Centrality (BC), which describes the influence of a given article on the transfer of information between the set of publications under study. Through the results it was possible to identify significant growth in the number of publications and citations. The countries with the highest number of publications are India (946), China (483) and the United States (247), with the US having the largest centrality parameter (BC), which reflects its prominent role in transmitting, information about spinel type ferrite. When analyzing the de-composition of WoS categories in large groups or clusters, we observed the predominance of three areas according to the number of co-citations: magnetic properties, electromagnetic properties and effect had electrocatalysis properties, which reflects the main objectives of research on this topic. Among the main keywords, “cobalt ferrite” has the largest BC parameter, revealing greater interest of the scientific community in Cobalt ferrite. The results of the clusters were corroborated from the identification of the main applications of spinel type ferrite in the last two years, in which the performance of these materials was observed predominantly in effluent treatment, magnetic devices, sensors and medical applications.
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