Mass spectrometry sniffs out adulterated saffron

An emerging analytical technique has been used to detect adulteration of saffron in minutes using a tiny test sample.

Pure, high-grade saffron is highly prized thanks to the distinctive aroma, taste and colour it can impart to foods. It is the most expensive spice in the world - costing upwards of €3,500 per kilo - so is a tempting proposition for unscrupulous individuals out to make a fast buck by peddling inferior material.

Saffron's high cost stems from its rarity, as it is derived from the stigmas of a tiny crocus grown in countries such as Italy, Iran, Spain, Greece and India. Around a hectare of land is needed to grow enough crocuses to produce 1kg-2kg of the spice.

A team of researchers describe in the journal Food Chemistry how a technique called proton transfer reaction mass spectrometry (PTR-MS) - generally used to monitor levels of volatile organic compounds (VOCs) in the atmosphere - can detect saffron adulteration quickly and effectively.

The technique can even identify the freshness of a sample, something which is not easy to achieve using other analytical methods that focus on measuring non-volatile compounds in the spice.

Prolonged storage of saffron leads to breakdown in some of the VOCs that are responsible for the spice's desirable properties and results in a lower quality product, particular with regards to aroma. In consequence older stocks of the spice are "often used as a bulking agent in saffron fraud," according to the scientists.

PTR-MS was able to screen for the presence of lower-quality saffron in a commercial products within around six minutes, using a sample of around 35mg.

"Considering that portable PTR-MS equipment is also available, this screening approach seems promising for on-site examination of saffron," they conclude.

The international Saffronomics initiative - which is trying to develop genomic testing tools for saffron - notes that -  adulteration and mislabelling are key problems affecting the sector and have contributed to a situation in which the European saffron industry is "in crisis."

Among the initiaitve's objectives is to start genomic typing of saffron as a tool for traceability applications, determination of authenticity, and for fighting against fraud of "origin, labelling and marketing."