Physicochemical analysis and determination of di- and tri-saccharide content in Longan, Litchi and Siam weed honeys of Thailand

Honeys produced by bees from the nectars of longan, litchi and Siam weed growing in Thailand were analyzed for physicochemical profiles (moisture, Brix%, soluble solids, density, viscosity, pH, free acid, electrical conductivity, HMF, DN, proline, color, flavonoid and antioxidant activities) and their carbohydrates quantified as monosaccharides, disaccharides and trisaccharides. All physicochemical parameters met the regulation requirements under the Codex Alimentarius Standard, EU Council and directives legislation of the Ministry of Public Health of Thailand, except the HMF value of one sample. The conductivity, color [Abs]450 and antioxidant activity were parameters that showed that there are significant differences in means between the groups of honey samples based on one way analysis of variance (ANOVA) (p < 0.05). The amounts of palatinose and isomaltose in the honey samples were statistical significantly different (ANOVA, p < 0.05). The differences between longan, litchi and Siam weed honeys by principle component analysis visible from the di- and trisaccharide profiles from an Rtx-65TG column were shown to be different from those from an SPB-1 column. The PC1 from the Rtx-65TG column profile was a linear combination that summarized 54.0% of the cumulative proportion of variance. The differences between the honey samples appeared to stem from many parameters and quantification compositions of the saccharides. The palatinose and isomaltose in longan honey were suggested to be markers for its authentication.