A palynological and geographical characterization of labeled resin spurge honey: Euphorbia resinifera

Abstract

Unifloral honeys are highly valued, and their botanical and geographical characterization plays an important role in quality control. This work is an essential contribution to the limited knowledge of the unique resin spurge (Euphorbia resinifera) honey. Palynological and geographical characterization was performed on 29 unifloral resin spurge honey samples distributed along the protected geographic indication (PGI) area in the Middle Atlas Mountains (Morocco). The quantitative pollen analysis show that resin spurge honeys were characterized by its low to very low pollen content (mean NPG =1490/g honey) and honeydew indicator elements (mean HDE =28/g honey). The most characteristic accompanying species are Ceratonia siliqua, Echium plantagineum, Olea sp., Plantago coronopus and Quercus. The proposed markers could further contribute as a useful tool to the quality control of the unique resin spurge honey and thus, guarantee its commercial value, both in the local and international markets. It also allows us to distinguish them from other unifloral honeys from highly related botanical origin, such E. officinarum subsp. echinus and E. regis-jubae honeys. The present characterization will allow further strengthen and protect the reputation of this honey especially since it is being registered in the EU list of protected products. Lastly, considering the lower percentage of E. resinifera pollen found in most of our resin spurge honey samples, we encourage for a revision of the established threshold and propose to lower it to 20% of pollen of E. resinifera to be considered as unifloral honey.