Effect of the vacuum-drying process of saffron on its pigment and volatile content and profile

Dehydration of the flower red stigmas of the Crocus sativus L. plant is necessary to yield “saffron” that is highly valuable in the global market both as a coloring spice and as a medicinal herbal product [1]. In the case of the Greek PDO “Krokos Kozanis”, traditional drying involves long exposure (12 – 24 h) of the fresh stigmas to mild, controllable temperature (25 – 30 oC). Such methods favour enzymatic degradation of crocetin sugar esters and picrocrocin that are responsible for saffron colour and taste respectively [2], leading to the formation of safranal and isophorone-related compounds as the major flavour constituents [3]. In the present study, we investigated the fate of those secondary metabolites (profile and concentration) after employing two vacuum drying methods to produce saffron at low to mild temperatures. Freshly collected stigmas from the Kozani region were exposed to different time, temperature, and tray load conditions until complete dehydration in the absence of oxygen. A sample dried according to the traditional method was used as a reference. The samples were examined macroscopically, via tristimulus colorimetry, FTIR spectroscopy, UV-Vis spectrophotometry, as well as liquid and gas-chromatographic techniques (HPLC-DAD, HS-SPME-GC-MS). The results highlight differences in the pigment and volatile profiles that help to understand the chemical transformation pathways. The antioxidant performance of the sample extracts in a lecithin-liposome oxidation model was also evaluated to highlight possible effects of the compositional changes upon drying. The results could be of interest to the local saffron producers and the relevant food/pharmaceutical industries.

• References

• 1 Ordoudi SA, Tsimidou MZ. Saffron quality: Effect of agricultural practices, processing and storage. In: Dris N, Jain SM. eds. Production Practices and Quality Assessment of Food Crops Preharvest Practice. Vol 1. 1st ed.. Dordrecht: Kluwer Academic Publishers; 2004: 209-260
• 2 del Campo CP, Carmona M, Maggi L. et al. Effects of mild temperature conditions during dehydration procedures on saffron quality parameters. J Sci Food Agric 2010; 90: 719-725
• 3 Raina BL, Agarwal SG, Bhatia AK, Gaur GS. Changes in Pigments and Volatiles of Saffron (Crocus sativus L) During Processing and Storage. J Sci Food Agric 1996; 71: 27-32

Publication History

Article published online:
12 December 2022