Caracterização da fração de óleo de café extraido de grãos sadios, verdes e preto-verdes, e a influência na adição deste na sensorial de café liofilizado

The application of roasted coffee oil directly on freeze dried soluble coffee is used to minimize the formation of fine poder which adhere on the glass packaging, which results in a negative visual appearance, as well as contributes to the aromatic impact when opening the packaging. The coffee oil is considered a high cost product obtained from Arabica coffee beans, previosly selected and roasted, by mechanical press. In Brazil the coffee culture and marketing results in the selection of the beans by type of defects and beverage, the volume of exportation works with types of coffee beans with low quantity of defects resulting in a large volume of defective coffee beans trading on the domestic market. Nevertheless, coffees which present defective grains like green, black-green beans present differences in the final flavor of the roasted coffees. The aim of this study was to evaluate the chemical composition of the oils extracted from grains classified as normal, green and black-green, at natural and roasted conditions. The oil was obtained by cold extraction using solvents of different polarities, and yield was calculated as well as its fatty acid composition. The oil of the roasted defective coffee grains was also used to prepare drinks of lyophilized soluble coffee in order to verify if jugdes were able to differenciate the sensory caracteristics of the beverages, in comparison to the product prepared using commercial oil obtained by mechanical pressing. Samples of oil obtained from defective grains showed similar extraction yields compared to hot extraction. Cromatographs of oils of the deffective grains did not showed differences compared to normal grains. In relation to the sensory analysis of the soluble coffee beverages, it was verified that when applying oils of light roasted black-green beans or oils of medium and dark roasted green beans obtained with rapid process, judges had more difficulties to distinguish differences between samples. Economic viability demonstrated that with the actual prices of the coffee beans, the use of defective beans could reduce in 64% the costs of the raw beans.

Avaliação do potencial da macrófita Pistia stratiotes na exposição de íon cromo (VI): biossorção e tolerância

The environmental pollution caused by industries has increased the concentration of pollutants in the environment, especially in water. Among the most diverse contaminants, there is the metals, who may or may not to be heavy/toxic, causing effluent of difficult treatment when in low concentrations. The search for alternative measures of wastewater effluent treatment has led to studies using phytoremediation technique through the various matrices (plant, fungi, bacteria) as means of polishing treatment to remove contaminants by means of biosorption/bioaccumulation. In order to use the phytoremediation technique for removing metals of the environmental, it have been performed bioassay with the macrophyte Pistia stratiotes. The bioassays were realized with healthy plants of P. stratiotes acclimatized in a greenhouse, at room temperature and lighting conditions during 28 days of cultivate. The cultivations were performed in glass vessels containing 1 L of the hydroponic solution with chromium (VI) in the potassium dichromate form with concentration range 0.10 to 4.90 mg L-1. The experiments were performed by Outlining Central Composite Rotational (OCCR), where the kinetics of bioaccumulation and chlorophyll a fluorescence were monitored in plants of P. stratiotes during cultivation. The collections of the samples and cultive solution were performed according to the OCCR. The chromium levels were measured in samples of P. stratiotes and the remaining solutions by the methodology of atomic absorption spectrometry by flame. The tolerance of P. stratiotes in relation to exposure to chromium (VI) was analyzed by parameters of physiological activity by means of chlorophyll a fluorescence, using the portable fluorometer PAM (Pulse Amplitude Modulation). The development of P. stratiots and their biomass were related to the time factor, while bioaccumulation capacities were strongly influenced by factors of time and chromium concentration (VI). The chlorophyll fluorescence parameters were affected by chromium and the exposure time at the bioassays. It was obtained an higher metal removal from the root in relation to the sheet, reaching a high rate of metal removal in solution. The experimental data removal kinetics were represented by kinetic models Irreversibly Langmuir, Reversible Langmuir, Pseudo-first Order and Pseudo-second Order, and the best fit for the culture solution was the Reversible Langmuir model with R² 0.993 and for the plant the best model was Pseudo-second order with R² 0.760.