British scientists devise way to measure hotness of chilli sauce

LONDON, May 6 (Xinhua) -- British chemists have developed a technique to measure the levels of capsaicinoids, the substance that makes chillies hot, in samples of chilli sauce, which might soon be available commercially as a cheap, disposable sensor for use in the food industry.

The technique, developed by Richard Compton and his team at Oxford University, is called adsorptive stripping voltammetry (ASV), and is a relatively simple electrochemical method, the science news website AlphaGileo reported Tuesday.

"ASV is a fantastic detection technique for capsaicinoids because it's so simple, it integrates over all of the heat creating constituents because all of the capsaicinoids have essentially the same electrochemical response," Compton was quoted as saying.

In the new method, the capsaicinoids are adsorbed onto multi- walled carbon nanotube electrodes.

As the capsaicinoids are oxidized by an electrochemical reaction, the current change is measured and the reading can be translated into Scoville units -- a unit of measurement devised in1912 by Wilbur Scoville to evaluate how many parts of sugar water is required to neutralize the heat of chillies.

For example, the relatively mild Jalapeno ranges from around 2,500-8,000 Scoville units, whereas the hottest chilli in the world, the "Naga Jolokia", has a rating of one million Scoville units.

The current industry procedure is to use a panel of taste-testers and is highly subjective.

The well-established Scoville method -- currently the industry standard -- involves diluting a sample until five trained taste-testers cannot detect any heat from the chilli.

High performance liquid chromatography (HPLC) can also be used, but this requires bulky, expensive equipment and detailed analysis of the capsaicinoids.

The new method unambiguously determines the precise amount of capsaicinoids and is not only quicker and cheaper than taste-testers but more reliable for purposes of food standards, as tests could be rapidly carried out on the production line.

The researchers tested a range of chilli sauces, from the mild "Tabasco Green Pepper" sauce to "Mad Dog's Revenge".

Compton has applied for a patent on the technology, and Oxford University's technology transfer subsidiary ISIS Innovation is actively seeking backers to commercialize the technique.