Exploratory Characterization of Artisanal Royal Jelly Produced by Apis mellifera siciliana Using 1H-NMR Metabolomics and NIR Spectral Fingerprinting

Italian production of royal jelly (RJ) is modest compared to imports, as domestic producers face much higher production costs than their foreign counterparts. To mitigate the competitive advantage of imported products, Italian producers could adopt marketing strategies emphasizing the local origin of their royal jelly. An especially interesting opportunity for Sicilian producers lies in RJ obtained from the siciliana spp. of Apis mellifera, commonly known as the black honeybee, rather than from the widespread A. mellifera ligustica. This study employed 1H-NMR and NIR spectroscopies to identify key metabolomic traits of artisanal royal jelly (n = 5) produced by A. m. siciliana in order to differentiate it from mass-produced (n = 5) and artisanal samples from A. m. ligustica (n = 6). Commercially available samples, whose market price was at least five times lower than Italian artisanal products, were used as references to represent mass-produced RJ from A. mellifera ligustica. To validate the suitability of the discriminant metabolites or wavelengths as potential biomarkers, an unsupervised multivariate model was built on these features and subsequently applied to additional artisanal samples produced by A. m. ligustica of known Italian origin. Among the 36 metabolites identified by 1H-NMR, seven showed statistically significant differences between A. m. siciliana and mass-produced samples. Notably, glucose, melibiose and UDP-glucose were more abundant in commercial samples. Artisanal samples from A. m. ligustica exhibited intermediate features between those from A. m. siciliana and mass-produced samples from A. m. ligustica, while specific differences between the two artisanal groups were also observed. NIR spectroscopy further confirmed distinct profiles between artisanal A. m. siciliana and mass-produced samples from A. m. ligustica, with Italian artisanal samples from A. m. ligustica showing greater similarities to the former.