Pollen composition and physicochemical properties of honey produced by three stingless bees species from a mesotropical subhumid region in Bolivia

Abstract

Honey produced by stingless bees has distinct nutritional and physicochemical properties that vary depending on the bee species, floral origin and environmental conditions under which it is produced. Honey diversity has been scarcely studied for most species managed in Bolivia. Moreover, the lack of legislation regarding honey quality parameters or pollen characterization allowing its identification hinders its commercialization. The present study analyzes pollen composition, through melissopalynological analysis, and the physicochemical properties of honey produced by the stingless bees Tetragonisca angustula, Scaptotrigona depilis and Scaptotrigona polysticta in a Boliviano-Tucumano forest. Moisture, ash content, free acidity, sugar profile, hydroxymethylfurfural, pH, water-insoluble solids, relative density and diastase activity were determined. Pollen diversity was determined, and a cluster analysis evaluated the similarity of pollen between honey samples. Almost all honey samples were monofloral, but honey from T. angustulawas more diverse. Similarly, pollen abundance in T. angustula honey was significatively higher than in S. depilis. Physicochemical parameters for T. angustula and S. polysticta honey met almost all the requirements (except reducing sugars for T angustutla and water-insoluble solids in both cases) of the Brazilian and Argentinean normatives for stingless bee honey while honey of S. depilis exceeded the limits in three parameters (non-reducing sugars, PH and water-insoluble solids). However, none of the honeys meet the parameter for moisture, reducing sugars and relative density in the Bolivian Normative. Additionally, S. depilis didn’t met the parameters for non-reducing sugars and PH. The design of a national legislation that adapts to the physicochemical singularity of every native species commonly bred in Bolivia is highly desirable.