In recent years the general public have become increasingly suspicious of food scientists. They are perceived as the employees of massive multinational corporations, who interfere unnecessarily with traditional wholesome foodstuffs converting them into health hazards. The long years of research carried out by Dr Colin Leakey at Cambridge do not easily fit with this image, his quest for the flatulence free bean is one that had defeated some of Europe’s finest scholars for more than 2000 years.
The broad bean was first cultivated in the Near East during the Neolithic period and was well known to the ancient Greeks and Romans. They offered bean cakes to their gods and used beans as a form of ballot paper in elections, black beans signifying a no vote and white beans a yes vote. Broad beans were originally small and black in colour, while more modern varieties have larger green or white seeds. The writings of the Greek scientist, Dioscorides reveal that even at this early date an over indulgence in beans had been associated with flatulence, dulling of the mind and in extreme cases, sterility. One can only assume that they were careful not to anger the gods by dedicating too many bean cakes to Apollo.
Throughout European history there are references to broad beans being considered as unsuitable cuisine for the aristocracy, because of their effect on polite company. A more serious affliction is the inherited allergy to broad beans called favism, which destroys red blood cells and causes anaemia, a condition which is particularly common in Iran and around the Mediterranean.
Beans and peas like other members of their family, the Legumes, contain bacteria in nodules on their roots which help convert atmospheric nitrogen into proteins. This means they can be grown in soils of low fertility, it is also why Legumes tend to contain more protein than do other plants. Around the world mankind has domesticated an impressive list of different species of beans as a source of non-animal protein. In Africa cow-peas were domesticated for both their dried seeds, known as black-eyed beans and for the fresh pods, called yard-long beans or asparagus beans. This is different from the asparagus pea, which is a native of the Mediterranean cultivated for its young pods. In Madagascar the four-angled beans was grown for its edible root tubers, it fresh pods, fresh or dried seeds and even its blue flowers are eaten in salads. India is the home of pigeon peas and the hyacinth bean, a beautiful climbing plants which is now grown as an ornamental in the southern United States as well as for its flattened seed pods. Very few of today’s crops originate from North America, the potato bean is a rare exception, its root tubers were not only eaten by the indigenous Indians, they also sustained the Pilgrim Farthers through their first winter in the New World. The Far East has given the world mung beans and adzuki beans, which are usually eaten as bean sprouts. The most economically important bean of the lot – the soybean was also first cultivated in China about 3000 years ago. From China the soybean spread to Japan and then with the assistance of an amazing feat of botanical espionage it was smuggled into Europe. In the seventeenth century Japan was a closed society, which protected its culture from outside influence by minimising all contact with the rest of the world. Thus it was that Englebert Kaempfer, of the Dutch East India Company and physician to the Governor of the Island of Deshima was allowed into Tokyo on the one day in the year in which the city was open to foreigners. Englebert did not waste his chance, and after bribing the local guards, he managed to grab a few soybean plants on route to the capital.
In Central and Southern America four closely related beans were domesticated. In the cool uplands, runner beans, in warmer temperate regions, common or French beans, the Lima or butter bean was grown in sub-tropical climes and the tepary bean was cultivated in semi-arid zones. In the high Andes water boils at well below 100 0C, to cope with this, the Incas developed beans that did not require boiling, but could be consumed after rapid frying. Although all four of these beans are now usually cultivated as annuals, actually only the tepary bean is truly so. In its native seasonally arid habitat the tepary bean has evolved unable to survive for more than a single year. In contrast, French beans, runner beans and butter beans can all live for several years, but being intolerant of frosts this is impractical when cultivated in temperate regions.
These American beans arrived in Europe via different routes. The runner bean was introduced to Britain in the early seventeenth century by the plant collector, John Tradescant the younger, the son of the famous plant collector John Tradescant the elder, in whose honour the tradescantia is named. For about 100 years, runner beans, were cultivated, purely as ornamentals for their attractive red flowers which resemble sweet peas, until Philip Miller of the Physic Garden in Chelsea rediscovered that the pods were good to eat.
The bright scarlet-red flowers of runner beans are not only attractive to gardeners, in their native South America they are visited by humming birds. Unlike insects which are unable to see the colour red, birds are attracted by it and bird pollinated flowers typically contain red pigments. This fact probably partly explains why many runner beans flowers fail to produce beans when grown in British gardens. The other three cultivated American beans are self-fertile and do not require the visit of a bird or a bee to produce seeds. The flower of the broad bean is a complex trip trap, which when triggered showers visiting bees with pollen, although some modern varieties are able to produce beans in the absence of a pollinating insect. Careful inspection of a few broad bean flowers will frequently reveal that instead of fighting the trip mechanism to gain access to the flower, bumblebees often bite a hole at the base of the flower to plunder their contents.
The French and butter beans were transported from Brazil to Africa in returning slave ships. From there the beans travelled north into Europe. The new arrivals were welcomed as the long wished for flatulence free beans. Pope Clement VII presented some of these new wonder beans to his niece, Catherine de’ Medici on the occasion of her wedding to the future king Henry II of France. It is not known if there was an incident at the reception, but the gift certainly failed to live up to expectations.
The problem with beans is that they contain large quantities of complex carbohydrates, lots of fibre and even toxic compounds, which in combination are not easily broken down by the human digestive system. These carbohydrates pass into the bowel where bacterial fermentation converts them into as much as two litres of gas per day. Various methods have been developed to avoid this problem. The simplest solution is prolonged cooking during which the complex carbohydrates are broken into simple sugars. The Americans employ a high tech method, they swallow enzyme tables, sold under trade names such as ‘beano’ which avoid embarrassment by chemically enhancing digestion. Dr Leakey’s research took him to South America and the markets of Chile. There he found apparently identical beans being sold for vastly different prices, when he made enquiries about this disparity the market traders appeared embarrassed but with the aid of basic sign language informed Dr Leakey that his search was over. Returning to Cambridge he was able to successfully hybridise his find to produce a flatulence free bean that could be grown in the U.K. As a nation the British consume two million pounds worth of baked beans a day, the potential implications of Dr Leakey’s research are therefore not to be sniffed at.