A novel method based on passive diffusion that reduces the moisture content of stingless bee (Heterotrigona itama) honey

摘要

Stingless bee honey from Heterotrigona itama exhibits a high moisture content (>27.0%) and therefore, is highly susceptible to undesirable microbial fermentation unless it is reduced to less than 20%. This study aims to reduce the moisture content of honey using a novel method based on passive diffusion and monitor the subsequent changes in several properties of honey. To achieve this, approximately 50 mL of freshly harvested honey samples was placed in clay pots (4 cm diameter x 6 cm height), covered with lids, and stored at temperatures of either 25 +/- 1 degrees C, 60% relative humidity (RH), or 35 +/- 1 degrees C, 25% RH. The results showed that the moisture content and Aw of honey after storage were significantly reduced (p <= .05) from 25.8 to 19.5% and from 0.79 to 0.70, respectively. A similar level of reduction was achieved at 25 degrees C, although this process took 21 days and resulted in some losses of honey solids due to cross-wall diffusion. The reduction in moisture content also resulted in a decrease in pH and free acidity of honey and an increase in viscosity. The data obtained in this study indicate the feasibility of using clay pots as an alternative method to reduce the moisture content in honey and protect it against fermentative deterioration. Practical Applications Stingless bee honey is highly popular in Malaysia and many other countries as it is high in carbohydrates and possesses many health benefits such as antioxidants and antimicrobial properties. However, the honey is susceptible to fermentation as its moisture content often exceeds the level required for microbial stability. Traditionally, the moisture content of stingless bee honey is reduced by drying the honey in shallow trays at elevated temperatures. However, this leads to contamination if the drying is performed under unhygienic conditions. Therefore, this study proposed the application of a passive diffusion method that serves as an effective alternative for moisture reduction in honey. It is anticipated that this method will not only reduce the moisture content but also retain most of its properties when the filtration process is performed under appropriate conditions.