Physicochemical properties, antioxidant profile and quality standard adherence of raw stingless bee honey from selected regions in Peninsular Malaysia

Stingless bee honey (SBH) is a highly nutritious food that can be influenced by various factors, such as climate and soil composition, depending on the geographical area where it is produced. Honey quality standards must encompass a broad range of characteristics to ensure that the final product meets the intended standards for high-quality and pure honey. In this study, forty-three SBH (Heterotrigona itama) samples were collected and labelled as <20 West Coast (<20WC), <40 West Coast (<40WC), <40 East Coast (<40EC), <20 East Coast (<20EC) and inland, according to their distance from the coasts. Firstly, the optimization of sugar profile methodology for trehalulose quantification was carried out using high-performance liquid chromatography (HPLC) with an evaporative light scattering detector (ELSD). Then, the SBHs were analyzed for their physiochemical properties, sugar profile, organic acid, minerals composition, bioactive compounds, and antioxidant capacities; total flavonoid content (TFC), total phenolic content (TPC), ferric reducing antioxidant power (FRAP), ABTS and DPPH radical scavenging activity assay, and oxygen radical absorbance capacity (ORAC) assay. The classification of SBH according to the geographical areas was performed using Principal Component Analysis (PCA). An HPLC-ELSD methodology was established, whereas using 88% ACN:12% DH2O and ELSD setting at 60 psi proved highly effective for separating sugars. Terhalulose was the most abundant sugar in H. itama SBH, with a mean of 39.0 ± 13.06 g/100g, and the optimized procedure was adequate and reproducible for identifying and quantifying trehalulose in SBH. Moisture, pH, electrical conductivity (EC), hydroxymethylfurfural (HMF), and sugar composition of all SBH samples adhered to the Malaysian Kelulut Honey Standard (MS2683:2017). SBH from <40EC had a darker colour with low L* and significant (p<0.05) lower colour parameters (a*, b*) compared to the other four geographical areas. Potassium (K) was found to be significantly (p<0.05) higher in SBH from the <40EC group compared to the Inland and <20EC groups Gluconic acid (GA) was significantly (p<0.05) higher in the SBH from the <40WC group than the <20WC group. Lactic, acetic, 3-phenyllactic acid (3-PLA), and phenylalanine were not significant (p>0.05) in SBH in all five geographical areas. TFC, TPC, FRAP, and ABTS scavenging activities were significantly higher in the <40EC samples. DPPH scavenging activity increased significantly in SBH from <20WC, while SBH from <20EC had higher ORAC activity. The PCA shows that the discrimination of SBH according to the five different areas was not feasible, indicating sample homogeneity. Pearson correlation shows that all antioxidant capacities positively correlate with EC, FA, Mg, K, P, acetic, and lactic acid. TFC and TPC are also moderately to strongly associated with FRAP and ABTS. 3-PLA also have a positive correlation with phenylalanine. In contrast, L* and b* showed a moderate to strong negative association with antioxidant capacities. For further research, conducting a more thorough investigation of both phenolic and volatile chemical fingerprinting can improve the capacity to discriminate between SBHs depending on their geographical origins and also include more samples from the East of Malaysia (Sabah and Sarawak) to see the fingerprint of those SBH based on geographical areas.

Text 122570.pdf Download (1MB) Official URL or Download Paper: http://ethesis.upm.edu.my/id/eprint/18615

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