Quality evaluation of saffron spice

Resumo

Saffron, dried stigmas from Crocus sativus L., is a spice capable of giving colour, taste and aroma to food. Consequently, it is considered a unique product but also because of special characteristics such as its limited production worldwide, the specific agricultural and manufacturing skills required, and its high price. Besides this, saffron quality control standards have not been developed at the same rate as for other food products due to the way it is commercialised: by small and medium family enterprises. This Dissertation presents five studies regarding saffron quality parameters and the results obtained from developing new analytical methods to assure its quality. Some methods have been developed with this purpose for: a) Picrocrocin determination using an SPE cartridge and a subsequent analysis using UV-vis spectrometry. The method provides for the quantification of picrocrocin content easily and quickly, which was not possible previously. b) Determination of free amino acids and ammonium content by HPLC-DAD. Results provided statistical differentiation of saffron samples from Europe as opposed to those from Iran. c) Determination of pesticides and contaminants using a stir bar for isolation (SBSE) and analysis by GC-MS/MS. Results revealed that sample contamination was higher than expected, but in general fell below the limits established by current legislation. Picrocrocin content has been analysed in more than 400 commercial samples, providing for the establishment of quality categories depending on picrocrocin content, and for inclusion in the current quality control standard. Finally, research on the effect of the saffron spice dehydration process on quality revealed that the highest temperature of those studied (55 ºC) is the most suitable for achieving the greatest colouring strength, the highest picrocrocin content and volatiles contributing to saffron aroma.