The physicochemical characteristics, antioxidant properties and botanical discrimination according to the organic acid content in Malaysian stingless bee honey were investigated. The results showed that the botanical origin and bee species significantly influenced the physicochemical characteristics and antioxidant properties of stingless bee honey. Principle component analysis (PCA) revealed that stingless bee honey was differentiable from Apis mellifera honey by acetic, citric, D-malic and tartaric. Starfruit could be distinguished from gelam and acacia honeys by lactic. Whereas the gluconic and succinic acids were confirmed as a marker to discriminate honey samples from Heterotrigona itama and Geniotrigona thoracica species.

This study investigated the simultaneous formation of polycyclic aromatic hydrocarbons (PAHs) and heterocyclic aromatic amines (HCAs) in gas-grilled beef satay at different temperatures (150, 200, 250, 300, and 350°C). Solid-phase extraction (SPE) was used for sample clean-up. Fifteen PAHs were determined using high performance liquid chromatography with fluorescence detection (HPLC-FLD) and nine HCAs were quantified using liquid chromatography tandem-mass spectrometry (LC-MS/MS) with a gradient programme. The lowest significantly concentrations of PAHs and HCAs were generated at 150°C; the formation of PAHs and HCAs simultaneously increased with temperatures. Benzo[a]pyrene was detected in all samples and increased markedly at 300 and 350°C. The sums of 4 PAHs (PAH4) in marinated beef satay at 300 and 350°C exceeded the maximum level in Commission Regulation (EU) 2015/1125. Significant reductions of polar and non-polar HCAs (except PhIP) were found in marinated beef satay across all temperatures. Overall, PAHs and HCAs showed opposite trends of formation in beef satay with marination.