Tracing the characteristic palynological profile of Spanish chestnut honey

Growing global demand for authentic, high-quality foods has intensified the need for reliable methods to verify product origin and composition, particularly for honey, a flagship product among natural foods. This study provides a comprehensive palynological characterization of 61 unifloral chestnut honey samples from Spain. Quantitative pollen analysis demonstrated that Castanea sativa honeys exhibit consistently high to very high pollen content (mean NPG = 454,090 grains per 10 g), with 95% of samples falling within Maurizio classes III–V. The accompanying pollen spectrum was dominated by Quercus, Cytisus, Rubus ulmifolius, Crataegus monogyna, Erica spp., and Cistus spp., which emerged as reliable secondary markers of botanical origin. These findings identify a distinctive pollen signature for Spanish chestnut honey and highlight its potential as a robust tool for quality control, authentication, and traceability in both domestic and international markets. Moreover, this work strengthens the palynological definition of chestnut honey, thereby contributing to the protection of its commercial and reputational value. Notably, the proportion of Castanea sativa pollen observed across the samples supports the establishment of a minimum threshold of 70% Castanea sativa pollen for the classification of Spanish unifloral chestnut honey, provided that the honey also exhibits the characteristic organoleptic properties traditionally associated with this botanical type and contains the principal accompanying pollen taxa identified in this study.