Objective. As propolis is a highly valued bee product, we aimed to verify the quality of aged propolis, investigating their phenolic and flavonoid composition, levels of toxic metals, radical scavenging and antimicrobial activities. Material and Methods. Samples of fresh and aged propolis of six different beekeepers, from the same geographical location, were investigated in terms of their phenolic and flavonoid composition and levels of Pb, Cd, and Cr, as well as radical scavenging and antimicrobial activities. Results. The two groups of propolis had similar qualitative composition by HPLC-PDA and ESI(-)-MS. Fresh propolis and aged propolis show no differences when average values of extraction yield, flavonoids, EC50, or MIC were compared and both types of propolis showed good antimicrobial activity at low concentrations. Only levels of phenolic compounds were higher in fresh propolis. Conclusion. The propolis samples considered in this study, aged or fresh, had similar qualitative composition, although they were collected in different periods. Samples only differed in their levels of total phenolic content. Moreover, aged propolis conserves significant radical scavenging and antimicrobial properties. We suggest that aged propolis should not be discarded but explored for alternative applications.

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A simple and fast analytical method for the determination of Cr, Pb and Cd in brown sugar by GF AAS using slurry sampling was developed and in house validated for the first time. Analytical curves were prepared by external standardization for Cr, and by matrix simulation for Pb and Cd and they were linear. Low limits of quantification for Cr (32.8 ng g), Pb (49.3 ng g) and Cd (4.5 ng g) were found. Repeatability and intermediate precision estimates (<10% and <15%, respectively) and recovery rates (95-103%) demonstrated a good precision and accuracy. The levels in brown sugar samples ranged from <32.8 to 160 ng g for Cr, from <49.3 to 211.0 ng g for Pb and from <4.5 to 7.0 ng g for Cd and they may be assigned to anthropogenic activities and the adoption of inadequate practices of production and processing.

Um planejamento fatorial foi aplicado para avaliar o conteúdo de cinzas em mel pela termogravimetria bem como para estabelecer as condições de análise ótimas que produzem conteúdos de cinzas em concordância com aqueles obtidos pelo método oficial (gravimetria). Os efeitos de taxa de aquecimento e papel de fibra de vidro foram significativos bem como o efeito de interação entre estas variáveis. Taxas de aquecimento e o emprego do papel de fibra de vidro são recomendados para obter a incineração completa de mel pela termogravimetria. Para confirmar estes resultados e estabelecer as condições otimizadas foi executado um planejamento completamente aleatorizado em blocos investigando três procedimentos: termogravimetria com papel de fibra de vidro a 5 e 10 ºC min -1 e gravimetria. Somente o método termogravimétrico realizada à 5 ºC min -1 apresentou conteúdos médios de cinzas em concordância com aqueles obtidos pelo método oficial. Assim, a TG/DTG pode ser indicada como um método alternativo à gravimetria para esta determinação em mel.A factorial design to evaluate ash content in honey by thermogravimetry as well as to establish the optimum analysis conditions that produce ash values in agreement with those obtained by the official method (gravimetry) was executed. Heating rate and use of fiber glass paper effects were significant as was the interaction effect between them. Lower heating rates and the use of fiber glass fiber paper are recommended to provide the complete incineration of honey samples by thermogravimetry. To confirm these results and to establish the optimized conditions a completely randomized two block design was executed investigating three procedures: thermogravimetry with fiber glass paper at heating rates of 5 and 10 ºC min -1 and standard gravimetry. Only the thermogravimetric method carried out at 5 °C min -1 presented ash content averages in agreement with those obtained by the official method. In this way, TG/DTG can be indicated as an alternative method to gravimetry for this determination in honey samples.