DOI: https://doi.org/10.55373/mjchem.v28i2.244

Keywords: Authentication, Chemometric classification, FTIR-ATR spectroscopy, physicochemical properties, stingless bee honey

Abstract

Stingless bee honey (SBH) is prized for its unique composition and health benefits, but its quality varies widely due to differences in bee species, flower sources, and processing techniques. Conventional physicochemical tests provide useful clues but not sufficient for reliable classification and differentiation from Apis mellifera honey (BH). The integration of these tests with advanced methods, such as Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy, provides a more robust and direct approach for authentication of the honey. SBH exhibited wide variation of moisture (11.33 – 37.33%), pH (2.89 – 4.66), free acidity (10.69 – 35.27 meq/kg), and electrical conductivity (66.63 – 1080.73 µS/cm), with some samples exceeding the Malaysian Standard (MS 2683:2017). Meanwhile, the FTIR-ATR spectra revealed distinct carbohydrate and organic acid bands and chemometric analyses provided robust classification. The principal component analysis (PCA) explained up to 100% variance clearly separating SBH from BH and clustering samples according to floral and compositional differences. Agglomerative hierarchical clustering (AHC) further distinguished three major classes based on physicochemical attributes reflecting differences in mineral content and acidity. The partial least squares-discriminant analysis (PLS-DA) achieved the most effective discrimination in the 3500 – 3000 cm^-1 region with strong model performance (R²Y = 0962, Q² = 0.684) and 100% correct classification of training samples, suggesting hydroxyl-rich compounds as key discriminators. Collectively, these findings demonstrate that integrating physicochemical tests with FTIR-ATR-chemometric modelling provides a rapid, reliable, and non-destructive framework for classifying and authenticating SBH, supporting the establishment of species-specific quality standards and strengthening consumer confidence in its commercialisation.