Organic versus conventional saffron production: apocarotenoid content and heavy metal contamination in Iran

Organic farming is widely recognized as a sustainable approach with potential to enhance the quality of agricultural products, including medicinal plants such as saffron. Despite the global importance of saffron, a comprehensive comparison between organic and conventional production systems across major cultivation regions has been lacking. This study aimed to evaluate the apocarotenoid composition (crocin and picrocrocin by HPLC; safranal by GC/MS) and heavy metal content (Pb, Co, As, Cr, Cu, Cd by atomic absorption spectroscopy) in saffron stigma samples from seven organic (OPS) and seven conventional (CPS) fields in Razavi Khorasan and South Khorasan provinces, Iran. Numerical trends suggested higher crocin levels in most OPS fields compared to CPS, while picrocrocin tended to be significantly higher in OPS samples (7.61 vs. 4.96 g per 100 g dry stigma). Safranal content numerically increased under organic management, although variations existed across regions. In most stigma samples, especially those from OPS, the levels of Co, Pb, and As were below the limits of quantification or detection. Cr and Cu levels in all stigma samples were well below their safe limits. Numerical trends suggest that the mean cadmium content was lower in OPS than in CPS. Regression analyses indicated negative correlations between cadmium and crocin-II, as well as between total heavy metals and picrocrocin. Overall, these findings suggest that organic saffron production shows numerical trends toward higher apocarotenoid content and lower heavy metal levels, indicating its potential to enhance saffron quality while maintaining food safety.