Honey physicochemical properties of three species of the brazilian Melipona

Physicochemical analyses were carried out to evaluate 27 samples of honeys from three species of the Brazilian genus Melipona (M. capixaba, M. rufiventris and M. mondury) from Espírito Santo and Minas Gerais States. The parameters water activity (Aw), percentage of soluble solids (Brix %), pH, acidity (meq/kg) and moisture (%) were evaluated. The honey characteristics obtained from these samples were very similar to the ones from other Melipona species. However, regarding the honey from Apis (honey bee), only the pH values were similar. The low pH value and the high acidity detected in Melipona honey are potential factors for increasing the honey shelf life because they do not provide favorable conditions for the microbial development. On the other hand, the high level of water activity favors the growth of microorganisms, especially yeast, which demands a more careful handled and storage. The observed differences between Melipona and Apis honey reinforce the need for specific quality settings for stingless bee honey.


INTRODUCTION
This work shown differences in values of water activity, Brix, pH, acidity and moisture between Melipona and Apis honey and reinforce the need for specific quality settings for stingless bee honey.
The Brazilian social bees, sub-tribe Meliponini, are considered the main pollinator agents of the Brazilian trees (kerr et al. 1996).There are more than 200 different Meliponini species, including the stingless bee, and some of them are frequently raised for honey production.
The honey physicochemical characteristics of these bees are not very well known, mainly in the tropical regions where there is a great flora diversity associated to high temperature and moisture.It is estimated that honey comes from more than 2.500 types of flowers from different plants; therefore their characteristics vary widely.Honey composition depends on several factors, such as nectar composition, source location, harvesting, season, management and especially bee species (Carvalho et al. 2006).
The aim of this work was to study the honeys of three species of the genus Melipona through physicochemical analyses.The water content is one of the main differences between honey from stingless bees and Apis.In general, it has been showed that the water activity values of honey from Apis (honey bee) ranged from 0.49 to 0.60 aW (Alcalá and Gómez 1990).This represents a non-satisfactory condition for the activity of several microorganisms that depend on a higher amount of free water for growth and survival.However, most honey showed water activity values (0.59 to 0.79 aW -Table I) higher than those from honey bees.The moisture content of honey is highly important for its shelf life (Pérez-Arquillué et al. 1994).In general, high moisture content causes honey fermentation, spoiling and flavor loosing, leading its loss of quality (Costa et al. 1999).
The moisture levels of M. capixaba honey (25.84 to 36.04% -Table I) exceeded the limits specified by the National and International legislations (20%).High moisture values have also been reported for honey from other Melipona species: 26.80% to 32.00% for M. asilvai (Souza et al. 2004), 23.14% to 32.50% for M. mandacaia, (Alves et al. 2005), 24.8% to 30.6% for the Amazon Melipona (M.compressipes manaoense and M. seminigra merribae) (Almeida-Melipona's HONEY PHYSICOCHEMICAL CHARACTERIzATION Muradian et al. 2007) and recently, for M. scutellaris (Ilha de Itaparica, Bahia State), and 25% and > 30% for M. quadrifasciata (Costa do Sauípe, Bahia state) (Carvalho et al. 2009).This feature deserves care in handling.On the other hand, the high moisture content is directly related to the flavor of the product that is much appreciated because it is less sweet and nauseating.
The honey of these three Melipona species showed a content of soluble solids ranging from 62.2% to 77.0% (Table I).This result corroborated Souza et al. (2006) who studied the honeys from M. compressipes triplaridis (67.0 to 75.5%), M. fuliginosa (68.0 to 75.0%) and M. panamica (57.2 to 75.0%).However, the brix value from Apis honey is higher (example, 78.8 to 84%; Terrab et al. 2004).Moreover, according to Anupama et al. (2003), there was a high negative correlation between brix % and moisture content in Apis honey.So, the lower content of soluble solids from Melipona honey may be related to their higher moisture content.
The pH values of Melipona honey ranged from 3.17 to 5.67 (Table I).This pH variation was previously reported by Almeida-Muradian et al. (2007) in the Amazon Melipona (mean value of pH 3.41), for M. scutellaris and in M. quadrifasciata honey, both from Ilha de Itaparica (mean values of pH 3.71 and 3.67, respectively) and from Costa do Sauípe (means values of pH 6.64 and 3.74, respectively) (Carvalho et al. 2009).These values are comparable to those reported for Apis honey from different countries.For example, it was 3.5 for the Italian honey (Esti et al. 1997), 4.2, 3.99 and 4.02 for the Spain honey (Terrab et al. 2004, Lópes et al. 1996).
The total acidic is the sum of free and lactonic acidities, and the maximum value accepted by the Brazilian legislation is 50 meq/kg (Brasil 2000).Regarding Melipona honey, the total acidic values ranged from 30.5 to 132.5 meq/kg (Table I) and this honey acidity is higher than the maximum recommended (Brasil 2000).It seems that high acidity is common for Melipona honey.For example, Vit et al. (1994) also reported elevated acidic values for M. compressipes (33.93 -94.12) and M. favosa (18.63 -228.80)honey.On the other hand, M. trinitati honey presented acidity values ranging from 12.92 to 35.30 (Vit et al. 1994) , M. scutellaris and M. quadrifasciata honey from Ilha de Itaparica presented acidity mean values of 25.75 and 55.0 and from Costa do Sauípe had acidity mean values ranging from 6.25 and 28.0 (Carvalho et al. 2009).Almeida-Muradian et al. ( 2007) also reported for the Amazon Melipona acidic values below 50 meq/kg (20.63 to 27.82).These last ones matched the reported data for Apis honeys from different geographical locations (e.g.Lópes et al. 1996, Esti et al. 1997, Terrab et al. 2004, Downey et al. 2005).As mentioned above, Melipona honey can present high levels of total acidic.Although high acidic is a feature that makes the honey attractive to consumers, it can indicates the state of honey maturity rising with fermentation.
The variations found in honey from Melipona species might be due to different honey sources, since the honey samples came from different biomas and sites.According to Carvalho et al. (2006), honey composition may vary depending on the flora, location, harvest season, management and especially the bee species that produced the honey.The low pH value and the high acidity represent a potential increasing of the honey shelf life because these conditions do not favor the microbial growing.On the other hand, it can be inferred that the high acidic values indicated the presence of undesirable fermentation, especially if honey presents higher contents of water activity and moisture.This might favor the microbial growing, specially yeasts, which suggests that this kind of honey needs to be handled and stored carefully to avoid microbiologic contamination.The observed differences between Melipona and Apis honey reinforce the need for specific quality settings for stingless bee honey.Moreover, further research is need for the establishment of quality patterns for the management of honey from native bees.
Honey from M. capixaba (n=9) was collected in May 2008 from hives in the Atlantic Forest at the cities of Alfredo Chaves, Domingos Martins and Venda Nova do Imigrante (Espírito Santo State).Honey from M. rufiventris Anais da Academia Brasileira de Ciências (2012) 84(3): 605-608 (Annals of the Brazilian Academy of Sciences) Printed version ISSN 0001-3765 / Online version ISSN 1678-2690 www.scielo.br/aabcLORENA G.A. LAGE et al. (n=7) was collected from April 2003 to May 2004 in the Brazilian savannah at the cities of Guimarânia, Patrocinio, Brasilandia de Minas and Dom Bosco.