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Effect of Drying Temperature and Air Flow on the Production and Retention of Secondary Metabolites in Saffron


Gregory, MJ and Menary, RC and Davies, NW, Effect of Drying Temperature and Air Flow on the Production and Retention of Secondary Metabolites in Saffron, Journal of Agriculture and Food Chemistry, 53, (15) pp. 5969-5975. ISSN 0021-8561 (2005) [Refereed Article]

DOI: doi:10.1021/jf047989j


Safranal is the compound most responsible for the aroma of saffron spice and is, together with the suite of crocin pigments, the major determinant of the product quality. The content of safranal and pigments in saffron is determined by the method of postharvest treatment of the Crocus stigmas. A range of drying treatments involving different temperatures, with or without air flow, was applied to stigmas from three harvest dates. Dual solvent extractions combined with quantitative measurement using GC and HPLC-UV-vis techniques were used to analyze the secondary metabolite contents of the products. It was demonstrated that these methods overcame the previously reported problems in measuring the concentration of both pigments and safranal in saffron caused by the very different polarities and thus solubilities of these compounds. The results showed that a brief (20 min) initial period at a relatively high temperature (between 80 and 92°C) followed by continued drying at a lower temperature (43°C) produced saffron with a safranal content up to 25 times that of saffron dried only at lower temperatures. Evidence was provided suggesting that drying with significant air flow reduced the safranal concentration. The results, moreover, indicated that high-temperature treatment had allowed greater retention of crocin pigments than in saffron dried at intermediate temperatures (46-58°C). The biochemical implications of the various treatments are discussed in relation to the potential for optimizing color and fragrance quality in the product. © 2005 American Chemical Society.

Item Details

Item Type:Refereed Article
Research Division:Agricultural, Veterinary and Food Sciences
Research Group:Horticultural production
Research Field:Post harvest horticultural technologies (incl. transportation and storage)
Objective Division:Plant Production and Plant Primary Products
Objective Group:Horticultural crops
Objective Field:Horticultural crops not elsewhere classified
UTAS Author:Gregory, MJ (Dr Matthew Gregory)
UTAS Author:Menary, RC (Professor Robert Menary)
UTAS Author:Davies, NW (Associate Professor Noel Davies)
ID Code:29950
Year Published:2005
Web of Science® Times Cited:69
Deposited By:Agricultural Science
Deposited On:2005-08-01
Last Modified:2006-05-03

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