Saffron Types and Quality Indicators

Pradip Poudel, Graduate Research Assistant,

Dr. Leigh Whittinghill, Assistant Professor of Urban Agriculture, and Dr. Hideka Kobayashi, Assistant Professor of Horticulture

The red-colored stigma threads are the main economic part of the saffron flower, and it is the most expensive spice in the world. To take advantage of high prices, saffron floral parts and foreign materials such as dyed corn silk, safflower petals, other flowers, wax, sugar, fat, or even inorganic compounds are sometimes added to make the final product heavier. The most common practice is to include the yellow and white colored style along with the stigma threads. However, these practices decrease the quality and price of saffron spice. Saffron quality depends on the level of three compounds; crocin (for color), picrocrocin (for flavor), and safranal (for aroma). These three compounds are concentrated in the red-colored part of the stigma threads; thus, adding any other flower parts or external materials decreases the saffron quality and market price. The International Organization for Standardization (ISO) sets the standard of saffron quality using three categories based on these three compounds' laboratory analysis.

ISO 3632 Categories of saffron

• Moisture content should be below 12 % on a mass basis in the filament form or 10% in the powder form.
• Moisture content should be below 12 % on a mass basis in the filament form or 10% in the powder form.
• Artificial colorant should be absent.

- ISO categorizes saffron into Category I (best quality), Category II, and Category III (lower quality) based on the laboratory analysis. Table 1 shows the ISO categories and their characteristics based on that analysis.

• Different floral parts like the style, petals, and foreign waste materials like dyed corn silk, wax, and sugar should be avoided for better quality.
• Picrocrocin, safranal, and crocin levels are expressed as absorbance of 1 % aqueous solution of saffron in 1 cm optical path length cell at 250 nm, 330 nm, and 440 nm wavelength, respectively.
• Different floral parts like the style, petals, and foreign waste materials like dyed corn silk, wax, and sugar should be avoided for better quality.
• Picrocrocin, safranal, and crocin levels are expressed as absorbance of 1 % aqueous solution of saffron in 1 cm optical path length cell at 250 nm, 330 nm, and 440 nm wavelength, respectively.