New way to test a chilli’s piquancy

Shock horror! Chilli sauce taste-testers could soon be back in the dole queue if research from the University of Oxford comes to fruition.

The current industry procedure for assessing the piquancy of chilli peppers is to employ a panel of trained taste-testers, using the well-established, though subjective, Scoville method. Named after its creator, American pharmacist Wilbur Scoville, the test involves diluting a sample until five trained tasters can detect no heat from the chilli.

The number of dilutions is called the Scoville rating. For a relatively mild pepper such as the jalapeño, the rating may range from about 2,500 to 8,000, whereas the world’s hottest chilli, the naga jolokia, has a rating of 1,000,000.

Currently, the only non-subjective alternative to taste-testers involves high performance liquid chromatography, which requires the use of bulky and expensive equipment, followed by detailed laboratory analysis of the capsaicinoids — the compounds that give the chilli pepper its pungency.

But the Oxford researchers’ technique apparently determines the precise amount of capsaicinoids quickly, cheaply and reliably and can be carried out rapidly on the production line.

According to a report in the Royal Society of Chemistry journal The Analyst, the Oxford chemists have found a way to measure the levels of capsaicinoids using carbon nanotubes. The capsaicinoids are adsorbed onto multi-walled carbon nanotube electrodes and the change in current as the capsaicinoids are oxidised by an electrochemical reaction can be translated into Scoville units.

By the way, chilli lovers might be interested to know that 21 January 2009 has been designated International Spicy Food Day.