Integrated analysis of pollen and volatile compounds to trace Calabrian honey floral origin: insights into floristic diversity

Composition and sensory properties of honey are strongly influenced by the plant species visited by bees, establishing a direct link between honey characteristics and its geographical origin. Characteristics of honey produced in a specific geographical area are primarily determined by local flora and climatic conditions, as flowering periods and nectar availability can vary significantly for the same plant species across different regions. Chemical and melissopalynological profiles are useful to determine both the botanical and geographical origin of honey: pollen extracted from honey represents a non-chemical analytical method, while volatile compounds -such as terpenes, norisoprenoids, and other aroma-active molecules- provide chemical signatures linked to the floral identity of the honey. The traditional method for determining the floral and geographical origin of honey is melissopalynology, which focuses on pollen analysis. In addition, the analysis of volatile organic compounds can reflect differences in their profiles, providing valuable indicators for botanical and geographical discrimination (1). Calabria has been recognized for its high potential in beekeeping, with 47.8% of its territory considered highly suitable for honey production (2), due to its favorable climate and rich floristic biodiversity. However, the composition of Calabrian honeys, in terms of pollen content and volatile profile, has not yet been described. This study aims to characterize honeys from four natural parks of Calabria (a wide region in Southern Italy): Pollino National Park, Sila National Park, Aspromonte National Park, and Serre Regional Park, protected areas with unique pedoclimatic and botanical features. The characterization is based on both melissopalynological and volatile compound analyses, used as botanical fingerprints, and analyzed through multivariate statistical tools to explore possible correlations among pollen profiles, volatile composition, and production areas. A total of 74 honey samples (produced during the 2023 and 2024 beekeeping seasons) were collected, mainly labeled as wildflower and chestnut honeys. Pollen analysis (3) was performed to identify characteristic pollen associations. The chestnut honeys produced during 2023 were submitted to volatile analysis via Headspace Solid Phase Microextraction followed by Gas Chromatography–Mass Spectrometry (Musci, Cirlini, & Caligiani, 2024). One hundred different pollen types belonging to 41 botanical families were identified. Regardless of local origin, all samples showed characteristic regional markers: the consistent presence of Castanea, Sulla, Echium, and species from the Oleaceae family. Samples from Serre Regional Park and Sila National Park were subjected to statistical analysis in order to explore potential differences in melliferous flora between the two areas. The volatile profiles of chestnut honeys revealed compounds typically associated with this floral origin, with minor differences related to the production area. The data obtained may help to distinguish Calabrian honeys from those of other geographical areas and provide a foundation for strategies aimed at promoting and protecting the unique botanical and ecological identity of these landscapes. 1) Musci, M., Cirlini, M., & Caligiani, A. (2024). Sampling techniques for the determination of the volatile fraction of honey 2) Zoccali, P., Malacrinò, A., Campolo, O., Laudani, F., Algeri, G. M., Giunti, G., ... & Palmeri, V. (2017). A novel GISbased approach to assess beekeeping suitability of Mediterranean lands. Saudi journal of biological sciences, 24(5), 1045- 1050 3) Louveaux, J., Maurizio, A., & Vorwohl, G. (1978). Methods of melissopalynology. Bee world, 59(4), 139-157