Discrimination of honeys produced by Tanzanian stingless bees (Hymenoptera, Apidae, Meliponini) based on physicochemical properties and sugar profiles

Abstract

Honey composition vary according to floral origin and bee species from which it is produced. Understanding the composition of honey is essential for guaranteeing its quality and authenticity, and revealing its potential benefits. Studies on honeys produced by Afrotropical stingless bees are scarce resulting into limited understanding and underutilization. The current study investigated the physicochemical properties and sugar profiles of honeys produced by six stingless bee species (Dactylurina schmidti, Hypotrigona gribodoi, Meliponula beccarii, Meliponula ferruginea, Meliponula togoensis and Plebeina armata) from different vegetation zones of Tanzania. Permutation analysis of variance (PERMANOVA) and Kruskal-Wallis tests were conducted to assess how bee species and vegetation influenced the studied parameters. Furthermore, we employed principal component analysis (PCA) and linear discriminant analysis (LDA) to discriminate honey samples according to bee species and vegetation zones. Our findings show that honey composition was greatly influenced by the identity of bee species which affected 84.6 % of the studied parameters, compared to vegetation zones which affected only 23.1 % of the studied parameters. Stingless bee honey showed significant variation from the international quality standards established for Apis mellifera honey. Also, the levels of free acidity (32.05–99.95 meq/Kg), ash content (0.09–0.81 % w/w) and reducing sugars (43.79–50.82 g/100 g) in some honey samples deviated from the East African Community standards for stingless bee honey. PCA and LDA revealed that the physicochemical properties and sugar profiles can be used to classify stingless bee honeys according to their bee species origin. We recommend further studies to elucidate essential markers that can be used in identifying the entomological source of stingless bee honey.

Keywords

• Stingless bee honey
• Meliponini
• Physicochemical properties
• Sugar profiles
• Quality standards