In this study honey samples produced by Melipona (Michmelia) seminigra merrillae, collected in seven counties distributed in the central and southern region of Amazonas state in Brazil, were analysed for their botanical origin, content and profile of phenolic compounds, and antioxidant and antimicrobial activities. Twenty-two pollen types were identified. The total phenolic content ranged from 17 to 66 mg GAE/g of extract; the highest contents were found in honeys produced from pollen types such as Clidemia and Myrcia. The antioxidant activity was higher in the samples that contained higher quantities of phenolic compounds. In relation to the antibacterial activity, samples CAD3, CAD4 and SAD3 presented the best results. Fourteen phenolic compounds were determined. Among them, we identified the flavonoid taxifolin, which has not previously been described in honeys from stingless bees, and we report the identification of catechol in Brazilian honey samples for the first time.

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Viscosity, the measurement of the internal flow resistance of a liquid, constitutes an intrinsic property of vegetable oils. It is of remarkable influence in the mechanism of atomization of the fuel spray, in other words, in the operation of the injection system. This property is also reflected in the combustion process, whose efficiency depends the maximum power developed by the engine. This work aims at assessing the rheological behavior of castor oil, castor oil biodiesel, and undegraded and degraded biodiesel at different exposure times and temperatures. Castor oil biodiesel presents viscosity higher than diesel oil, but this drawback can be corrected by means of blends of both components at different proportions. The viscosity data indicated that the heat treatment leads to a degradation of the samples accompanied by an increase of the viscosity, probably because of interactions with intermediary compounds. The degraded samples presented a pseudoplastic behavior, once the flow index, m, is smaller than 1.

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