Abstract In the present study, we evaluated the physicochemical characteristics (color, humidity, soluble solids, free acidity, pH, ash content, carbohydrate content, and 5-HMF) and antioxidant activity (Folin-Ciocalteu reagent and DPPH free radical scavenging) of honey samples produced by different species of Meliponinae subfamily (n = 16) and A. mellifera (n = 16) from the Eastern Brazilian Amazon region. Considering global averages, the stingless-bee honey had high acidity (93.45 mEq kg-1), high humidity (27.43%), low content of reducing sugars (55.65%), and darker colors (Pfund scale – 162.17 mm), when compared with A. mellifera honey (62.96 mEq kg-1, 19.35%, 65.70% and 68.43 mm for the respective parameters). Furthermore, more than 50% of samples of stingless-bee honey had values of 5-HMF above that proposed by Codex Alimentarius (max. 80 mg kg-1). The two types of honey investigated showed similar results for total phenolic compounds and antioxidant activity. The principal component analysis (PCA) of the physicochemical characteristics of the honey samples, showed that the A. mellifera samples formed a differentiated group, while the multi-species Meliponinae samples were more scattered along the PCA axes. The distinctive characteristics of stingless-bee honey compared to A. mellifera honey produced in the same region, reinforces the need for specific regulations for honey produced by stingless-bees.

RESUMO O mel é um produto natural que apresenta várias propriedades benéficas para a saúde, tais como atividade antinflamatória, antioxidante e antimicrobiana, as quais dependem de sua composição. Neste contexto, as propriedades físico-químicas (cor, pH, conteúdo de cinzas, umidade, açúcares e compostos fenólicos totais) e a atividade antioxidadente (capacidade de remoção do radical DPPH) de méis de abelhas Apis mellifera de Santarém, na principal região de produção de mel na Amazônia Oriental, Brasil, foram avaliadas. A maioria das amostras teve cor escura e apresentaram-se ácidas. Os teores de cinzas e a umidade variaram de 0,112 a 0,318 e de 14,751 a 17,514, respectivamente. O teor de açúcares redutores vairou entre 62,873 e 91,563%. O teor total de compostos fenólicos foi mais elevado que os já reportados na literatura, variando entre 15,22 e 16,51 mg g−1 e 17,70 e 18,94 mg g−1 para amostras de mel protegidas e expostas à radiação UV, respectivamente. A quercetina foi encontrada apenas no mel que foi protegido da luz, com teores variando entre 0,24 e 0,43 mg g−1. A ausência de quercetina nas amostras de mel expostas à luz sugere que a radiação UV pode ter degradado esse composto. Todas as amostras apresentaram máxima capacidade de remover o radical DPPH próxima a 50%. Houve correlação inversa entre a cor e o pH, cinzas, açúcares redutores e teor de umidade, e correlação positiva entre a cor e o teor de composto fenólicos e a atividade antioxidante.

ABSTRACT Honey is a natural product that has several beneficial properties for health, such as anti-inflammatory, antioxidant and antimicrobial activities, which depend on its composition. In this context, physicochemical properties (colour, pH, ash, moisture, sugars, and total phenolic contents) and antioxidant activity (DPPH radical scavenging ability) of Apis mellifera honeys from Santarém, the main honey production area in the eastern Amazon region, were evaluated. Most samples were dark in colour and acidic. The ash and moisture contents ranged from 0.112 to 0.318 and from 14.751 to 17.514, respectively. The reducing sugars content was 62.873-91.563%. The total amount of phenolic compounds was higher than normally reported, ranging between 15.22 and 16.51 mg g−1 and 17.70 and 18.94 mg g−1, for honey after and before exposure to light, respectively. Quercetin was found only in honey that had been protected from light, with values ranging from 0.24 to 0.43 mg g-1. The absence of quercetin in the samples of honey exposed to light suggests that UV radiation has degraded this compound. All samples presented maximum radical scavenging capacity close to 50%. Our results showed inverse correlations between the colour and pH, ash, reducing sugars, and moisture content, and positive correlations between the colour and the concentration of phenolic compounds, and antioxidant activity.