RE S EARCH Potatoes keep you young and cardiovascular diseases shown in many studies includes the activity of flavonoids. Furthermore, they can act on the enzyme and hormonal systems in the human body and the immune system. Navarre also mentions the positive effect on respiratory diseases such as asthma and lung cancer. Also antihypertensives Just as important are the kukoamines, which are also antioxidant. British food scientists at the independent Institute of Food Research (IFR) in the English town of Norwich already discovered this substance three years ago in a number of the most common potato varieties. Kukoamines are natural substances that act as an antihypertensive. It is not even five years ago that food scientists thought that kukoamines only occurred in certain exotic plants. In their herbal medicine, the Chinese have been making extracts from the cortex of the rare plant Lycium chinense, which contains kukoamines, for example. Big differences per variety The in-depth search for potato substances also puts this dietary source in a different light. It is suddenly not only a starch or carbohydrate bomb but also an important source of healthy food, according to Navarre. It also gives a different outlook on the production method. For years, the method focused on producing as many kilograms per hectare as possible. However, if we want the potato to contain as many healthy substances as possible, it needs both a different breeding method and other cultivation methods. The Slow Food International organisation and a research institute such as the Louis Bolk Institute are known to have researched cultivation methods for years. The fact that cultivation and breeding activities are so important are shown by Navarre’s analyses. In all hundred researched potato varieties, the highest measured concentration of flavonoids is already thirty times higher than the lowest measured concentration. Navarre considers it possible that breeders could increase the content in new varieties through a higher breeding level. Faster research methods The reason that it has taken so long before we now know so much about potato substances is, among other things, the result of the availability of a new research method. Navarre is currently using an analysis with which he can screen the potato completely within twelve minutes. By testing wild and common potato varieties, the researcher has established that the concentration of phenols vary from 100 to 652 milligrams per 100 grams of dry matter. The highest concentrations were found in red-skinned varieties and in typical American table varieties such as the Norkotah. These varieties easily compare with vegetables with very high concentrations of antioxidants such as broccoli and Brussels sprouts. Search continues At present, Navarre and his research team are looking for the causes of the big concentration differences of phenols in the Navarre is currently using an analysis with which he can screen the potato completely within twelve minutes. The highest concentrations of phenols were found in red-skinned varieties and in typical American table varieties such as the Norkotah. At the present moment, the number of discovered phytochemicals and vitamins in the potato is sixty, among which a few that are well-known such as the vitamins C, B1, B2, B3, and various minerals such as potassium and sodium, but also less well-known substances such as flavonoids and kukoamines. various potato varieties. ‘We are looking at the influence of four genes, which are involved in the formation of folic acid. Why does one variety have more of that substance than another, for example?’ The results of that study will most probably become available during the course of this year. That would be fantastic, because it would mean that the American researchers are giving ‘The Year of the Potato’ even more lustre than it already has. ● Leo Hanse Potato World 2009 • number 3 15 Pagina 14
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