# A Comprehensive Review of Stingless Bee Products:
## 2 Stingless Bee Honey
Moisture content in stingless bee honey is reported to be higher than European honeybee honey, which is contributed by the benefit of abundant rainfall and high humidity in a rainforest [20]. Several reports that comply with the Malaysian Standards and those proposed by [PERSON] et al. [15] are from the _Tetrigona apialis_ ([PERSON], 1857), _Tetrigona melanoucca_, _Melipona marginata_, _Melipona quadrifuscita_, _Melipona flavolineata_ ([PERSON], 1900), _Tetrigona binghami_ and _Homotrigona fimbriata_ ([PERSON], 1857) species [11; 19; 20; 23]. Ash content is also used to measure the quality of honey, as it represents the mineral content present and can also be used to evaluate the nutritional value of honey, which is mostly affected by the potassium content [24]. The mineral content that correlates to \begin{table}
\begin{tabular}{c c c c} \hline \hline \multicolumn{4}{c}{**Standards**} \\ \cline{2-4} Parameter & \begin{tabular}{c} **International Honey Commission** \\ **(European Honeybee Honey)** \\ \end{tabular} & \
\begin{tabular}{c} **[PERSON] et al. [15]** \\ **(Stingless Bee Honey)** \\ \end{tabular} &
\begin{tabular}{c} **Department of Malaysian Standards** \\ **(Stingless Bee Honey)** \\ \end{tabular} \\ \hline Moisture (g/100 g) & \(\leq\)20 & \(\leq\)30 & \(\leq\)35 \\ Sum of fructose and glucose (g/100 g) & \(\leq\)60 & \(\leq\)50 & \(\leq\)85 \\ Sucrose (g/100 g) & \(\leq\)5 & \(\leq\)6 & \(\leq\)7.5 \\ Malose (g/100 g) & & - & \(\leq\)9.5 \\ Free acidity (mg/100 g) & \(\leq\)50 & \(\leq\)85 & - \\ Ash content (g/100 g) & \(\leq\)0.5 & \(\leq\)0.5 & \(\leq\)1.0 \\ Electrical conductivity (mS/cm) & \(\leq\)0.8 & - & - \\ Hydroxymethylfurfural (HMF) content (mg/kg) & \(\leq\)40 & \(\leq\)40 & \(\leq\)30 \\ Diastase activity (DN) & \(\geq\)8 & \(\geq\)3 & - \\ pH & - & - & 2.5 to 3.8 \\ Phenolic compounds & - & - & Present \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of European honeybee honey standards with stingless bee honey standards. ash content is due to the composition of the source of plant nectar from which the nectar bearing plant absorbs minerals from the soil [7]. Some of the reports of ash content that comply with all standards are from the species _Geniotrigona thoracica_[19; 21; 25; 26], _Scaptotrigona mexicana_ ([PERSON], 1836) [27], _Heterotrigina itama_[20; 26], _Lepidortigona doipensis_ ([PERSON], 1939), _Lepidortigona flavibasis_ ([PERSON], 1929), _Lepidortigona terminata_, _Lisorigona fura_ ([PERSON], 2000), _Tetragonilla collina_ ([PERSON], 1857) [11], _Melipona bicolor_ ([PERSON], 1836), _Melipona quadrificaita_, _Melipona marginata_, and _Scaptotrigona bipunctata_[23]. According to the IHC Standards, electrical conductivity should not be more than 0.8 mS/cm, whereas [PERSON] et al. [15] and the Malaysian Standards do not define any threshold. Some of the reports that comply with the standard are from the species _Scaptrigona Mexicana_[27], _Geniotrigona thoracica_[19; 25], _Heterotrigona Baker_[19], _Lepidortigona terminata_[25], _Tetragonula laevis_[25; 28], and _Scaptotrigona bipunctata_[9; 23]. The parameters used to evaluate freshness and overheating of honey are the hydroxyymethylfurural (HMF) content and diastase activity. HMF is formed by breaking down fructose in the presence of acid, and its value increases when heated, during longer time storage, or during adulteration using sugar syrup [29]. However, stingless bee honeys are usually accused of being adulterated due to the high HMF content. Apparently only IHC and [PERSON] et al. [15] have proposed standards to set a threshold of a maximum of 40 mg/kg, whereas the Malaysian Standards do not state any threshold.