The Chip Is A Complex Thing

Ruzanna Harutyunyan's picture

Just a hint of the tantalising smell of a portion of chips is often enough to whet our appetites. But have you ever wondered just what it is about the aroma of one of Britain's favourite foods that we love so much?

The appeal of their smell could actually be down to the range of different aromas chips contain. Aromas including butterscotch, cocoa, onion, cheese and would you believe ...ironing boards, all combine to help make chips one of Britain's iconic dishes.

The research, which was carried out for National Chip Week 2009 used laboratory analysis and human noses, as well as focus groups to sniff out the chips with the most tempting smell.

Scientists from the University of Leeds, University of Reading and Leeds Metropolitan University worked together to collect the aroma from cooked chips, then separated the different compounds for analysis by a ‘aroma-meter' machine. 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 from the University of Leeds 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.


"One might not expect to find butterscotch or cocoa aromas in chips, but it has to be remembered that these are one part of the overall aroma. Perhaps these findings will see chips treated like wine in the future - with chip fans turning into buffs as they impress their friends with eloquent descriptions of their favourite fries."

The research showed that the relationship between the potatoes, the oil, the temperature and cooking, as well as adding condiments or foods, affects the aroma profile of the chips.

Dr Clayton said: "Like a fine perfume, chips can be made up of different aroma combinations, so there is always something for everyone and every occasion. Lightly cooked or undercooked chips were found to contain three simple aromas including bitter cocoa. A little extra cooking was shown to produce a more complex aroma profile, with up to nine different aromatic notes."

Scientific Method

Focus Groups were undertaken at Leeds Metropolitan University to look at the consumer perception of chips. Many of the findings in these groups were further developed in the omnibus research. Texture, appearance, aroma and taste were the preferred attributes in that order although there were differences amongst the participants: men prefer taste and texture whilst for women aroma is very important.

The aroma was further examined analytically by comparing chips that were slightly undercooked with those that were slightly overcooked. The aroma from the chips was collected and trapped by scientists at the University of Reading and then analysed by separating the aroma into its separate parts (via a process known as Gas Chromatography Mass Spectrometry or GCMS). The output of the analysis is a series of peaks on a graph or a fingerprint. Each peak indicates the occurrence and levels of a different component of the aroma.

Each peak was also sniffed by an analyst to record if it could be detected and the type and strength of the aroma recorded.