The desirable aroma of Fries: A fine bouquet of butterscotch, cocoa and cheese - with a hint of ironing board

Scientists at Leeds University have analysed why the tantalising smell of a portion of chips is often enough to whet our appetites.

They have found that the appeal of their smell could actually be down to the range of different aromas chips contain.

Nine aromas including butterscotch, cocoa, onion, cheese and even …ironing boards, all combine to help make chips one of Britain's iconic dishes, it is said.

The research, which was carried out for National Chip Week 2009, was led by Dr Graham Clayton of the Department of Food Science using laboratory analysis as well as human focus groups to pinpoint the chips with the most tempting smell.

Scientists collected the aroma from cooked chips, then separated the different compounds for analysis by Gas Chromatography Mass Spectrometry - a technique used to separate foods into their base elements.

Those that could be detected by the human nose were sniffed, and the type and strength of smell recorded. The findings show that those chips that are cooked twice have more complex aromas comprising bitter cocoa, butterscotch, cheese, earthy potatoes, onions, and flowers

Dr Graham Clayton said: "Whether oven-cooked or fried, the humble chip doesn't smell of just chips – the aroma is much more complex and probably explains why chips are everyone's favourite.