Comparative Effects of Thermal and Ultrasound Processing on the Quality and Functional Properties of Thai Stingless Bee Honey

Stingless bee honey (SBH) is a functional food rich in bioactive compounds, but thermal processing may adversely affect its quality. This study compared conventional thermal treatment (65°C, 20 min) and ultrasound processing (20 kHz, 20 min; 40–80% amplitude) on the quality, antioxidant activity, microbiological quality, and sensory acceptability of Thai SBH produced by Tetragonula pagdeni (Schwarz). Ultrasound at 60% amplitude showed a favorable overall quality profile, maintaining viscosity (2.81 Pa·s) and diastase activity (8.36 DN), comparable to untreated honey (2.84 Pa·s and 8.42 DN). HMF was 9.18 mg/kg, compared with 8.62 mg/kg in untreated and 31.87 mg/kg in thermally treated honey. Ultrasound at 60% amplitude increased measured TPC and TFC to 756.3 mg GAE/kg and 136.2 mg QE/kg, respectively, versus 682.4 and 118.5 mg/kg in untreated honey, and produced the highest antioxidant activities (p < 0.05). Both processing methods reduced measured microbial counts immediately after treatment, while 60% ultrasound achieved the highest sensory acceptability (p < 0.05). Overall, 60% ultrasound provided a favorable quality profile, supporting further investigation for SBH processing.