UMAMI, a 100-year-old Japanese concept of flavour, may hold the key to breeding the perfect potato.
Favourite varieties contain higher levels of the compounds linked to umami flavour
Experts at the Scottish Crop Research Institute (SCRI) at Invergowrie near Dundee have discovered which compounds give potatoes their distinctive "umami" taste.
The scientists are hopeful that their study will be used to create new varieties even more tasty than their predecessors.
Umami has been scientifically accepted as one of the five individual tastes sensed by receptors on the tongue, along with salty, sweet, bitter and sour.
Although there is no equivalent word in English, umami has been used to describe the slightly savoury taste that people encounter when they eat ripe tomatoes, parmesan cheese, cured ham, mushrooms, and various types of meat and fish.
Dr Mark Taylor, the SCRI scientist who led the research, said: "Umami is almost a savoury-like flavour and that is obviously considered to be important when it comes to judging the taste of a potato. It was certainly the case in our taste trials.
"There was a suggestion back in the 1970s that umami was important for potato flavour, but there was never any evidence to back it up until we did our trials."
The potato varieties that score highest when it comes to flavour have higher levels of the compounds known to give rise to the umami flavour – specific chemicals, which include some amino acids and "ribonucleotides" that are formed during cooking.
The research team conducted taste tests to compare traditional Solanum tuberosum varieties, including Montrose, Pentland Dell, Maris Piper and Record, which are widely grown in Scotland, with new, Andean-style varieties of so-called Phureja potatoes, which tend to be thinner and longer. The new varieties tested included Mayan Gold and Inca Sun – which derive from the Peruvian homeland of the potato. The Peruvian potatoes came out on top.
"We found that the Phurejas always had more of the umami compounds and that there was a correlation with the taste-panel score," said Dr Taylor.
"It is probably not the only story because the potato has a pretty complicated flavour, (but] it may be the key."
He added: "Ultimately, we would like to know which genes control the process that leads to the formation of umami compounds and these genes could be used in breeding programmes to generate a tastier potato."
SOMETHING TO SAVOUR• Umami was first identified as a taste in 1908 by Dr Kikunae Ikeda, a scientist at the Tokyo Imperial University while researching the strong flavour in kombu, a seaweed broth.
• Many scientists argued that umami was not a separate sense, but simply a combination of the other four tastes – salty, sweet, bitter and sour.
• In 1996, a team of researchers at the University of Miami discovered separate taste receptor cells in the tongue for detecting umami.
They also found that animals were able to savour umami.
