Comparative analysis of microbiological, physicochemical, antioxidant and antibacterial properties of stingless bee (Tetragonula pagdeni Schwarz) honey from various agricultural areas in Eastern Thailand

Abstracts: This study examined the physicochemical, microbiological, antioxidant, and antibacterial properties of honey derived from stingless bees (Tetragonula pagdeni Schwarz). The honey samples were from different botanical zones in Sa Kaeo province, recognized as a ''herb hub'' in eastern Thailand. The analysis of 17 stingless bee honey (SBH) samples revelaed an average moisture content of 25.67 ± 2.43 %, protein content of 1.99 ± 0.11 g/100 g, ash content of 0.77 ± 0.42 g/100 g, total soluble solids (TSS) of 77.19 ± 1.31°Brix, hydroxymethylfurfural (HMF) level of 0.036 ± 0.026 mg/g, pH of 3.9 ± 0.19, and free acidity of 127.28 ± 52.63. The sugar composition was analyzed, revealing an average glucose content of 19.56 ± 7.02 g/100 g, fructose content of 29.52 ± 7.19 g/100 g, estimated reducing sugars (sum of fructose and glucose; F + G of 49.08 ± 13.85), estimated fructose/glucose ratio (F/G) of 1.60 ± 0.37, and estimated glucose/water ratio (G/W) of 0.77 ± 0.27. The antioxidant activity was assessed using ABTS and DPPH with average IC50 values of 4.42 ± 0.87 and 46.99 ± 10.68, respectively. The SBH exhibited an inhibitory effect against Salmonella enterica (10.39 ± 3.02 mm), Escherichia coli O157:H7 (9.38 ± 1.95 mm), Staphylococcus aureus (11.81 ± 5.01 mm), Bacillus cereus DSM4384 (6.90 ± 3.55 mm), and Bacillus cereus F4810/72 (10.78 ± 2.71 mm) with the agar well diffusion method. Furthermore, the principal components analysis demonstrated that vegetation type influenced the physicochemical and antibacterial properties. Microbiological assessments were conducted to evaluate the quality and food safety of SBH. We analyzed the total bacteria, total yeast and mold, coliforms, E. coli, S. aureus, and presumptive Salmonella spp.. We additionally investigated the culturable bacteria and their enzymatic activities. Bacillus constituted the predominant bacterial isolates from SBH, and numerous isolates exhibited the ability to produce hydrolytic enzymes advantageous for industrial applications.