Kelulut stingless bee honey stored under different thermal conditions: Non-destructive assessment

Kelulut honey (Heterotrigona itama) is gaining popularity, which makes its quality assessment an important issue. We employed the method of near-infrared spectroscopy to perform a non-destructive quality assessment of refrigerated and non-refrigerated postharvest Kelulut honey. The research objective was to define the physical and chemical properties of Kelulut honey stored for 0, 1, 2, 7, and 14 days, as well as to establish effective prediction models based on the methods of principal component regression and partial least squares. The Brix value, moisture content, and sugar content exhibited no significant differences (p > 0.05) for the entire storage time. However, the Brix value and sugar content decreased as the moisture increased during storage. pH values decreased while the hydroxymethylfurfural content increased across the entire storage time. Significant differences (p > 0.05) were observed between the pH and hydroxymethylfurfural values for honey stored at different temperatures. The prediction model of sugar content based on principal component regression demonstrated acceptable accuracy (R2 = 0.7) and low mean squared error. After pre-processing and partial least squares regression, the method of near-infrared spectroscopy proved accurate and effective in defining the quality of Kelulut honey.