Nuclear Magnetic Resonance-Based Quality Assessment of Vermont-Grown Saffron (Crocus sativus L.)Optimal Drying Conditions and Mechanistic Implications

As a promising high-value crop for small- to mid-sized farms, saffron (Crocus sativus L.) contains valuable bioactive components such as crocins, picrocrocin, and safranal, which were suggested to have potential activity to treat cancers, digestive inflammatory disorders, and Alzheimer’s disease. However, the concentrations of these bioactive components can greatly depend on environmental factors during growth and on postharvest handling. In this work, a new analytical method has been established to measure the relative amounts of these bioactive compounds, using mild extraction conditions in combination with nuclear magnetic resonance (NMR) spectroscopy. We applied our NMR-based analytical technique to establish how the concentrations of crocins, picrocrocin, and safranal in Vermont-grown saffron are impacted by different dehydration methods. Our results indicate that saffron samples dried at a high temperature (100 °C) contain more safranal and crocins and that picrocrocin converts into safranal at an elevated temperature. Density functional theory calculations provide a new mechanism for this conversion, indicating that enzymes are not required for this process. Our NMR-based extraction and analysis method can be applied to other medicinal plants in the future to help optimize growth and postharvest drying/storage conditions.