FOOD & DRINK / Cracking the eggplant: For centuries the aubergine has baffled science and delighted cooks. Michael Bateman learns the dark secrets of the enigmatic vegetable

SPANISH aubergines are back in the shops. Isn't that splendid news? Something with a bit of flavour after a winter of having to buy those tasteless Dutch greenhouse varieties.

It's fashionable to blame modern horticulturists for mucking up our fruit and veg, and you can certainly blame the plant scientists for wilfully removing the taste from tomatoes; to extend the shelf-life they use their knowledge of genetics to inhibit the natural ripening process. But since the aubergine is a vegetable that is uneatable when 'ripe' this stricture doesn't apply. The worst thing the plant breeders have done is to produce aubergines of uniform size with a good, firm shape and shiny, strong-coloured skins.

The average aubergine is nothing but a shiny purple balloon that has been pumped up with water rather than air. It contains a bare seven per cent of dry matter; 92.7 per cent of an aubergine is water. And as for the taste, an aubergine has only one flavour, and that is bitterness.

The aubergine has long been misunderstood by the British. The first time around, according to a Turkish source, when it was introduced from the Middle East in the 17th century, it was dubbed a mad-apple and its import forbidden. It only returned from exile due to the patronage of certain writers, first Elizabeth David (who introduced us to the Provencal vegetable stew, ratatouille, in 1950 in A Book of Mediterranean Food) and then Jane Grigson in her Vegetable Book and Claudia Roden in her New Book of Middle Eastern Food.

Yet the aubergine has always been used as a matter of course in the Mediterranean and among the eastern communities in Britain; in Italian restaurants they serve stuffed aubergines in tomato sauce, melanzane ripieni; you may find the famous Turkish stuffed aubergines, imam bayildi (which means fainting prince - he fainted with delight), and in Greek-Cypriot restaurants the aubergine is the basis of moussaka. The aubergine is also extremely common in Indian restaurants, where it is known as brinjal.

Exactly where the aubergine originates is disputed. They come in many sizes and shapes other than the purple balloon. The small, white, round fruit common in India gave rise to the name eggplant. Japan, China and the Middle East have a long history of using aubergines, but the weight of evidence suggests India and Burma, because old Sanskrit texts have no fewer than 33 words for the aubergine, such as 'royal pumpkin', 'blue fruit' and 'excellent vegetable'. Other names suggest their properties because parts of the plant were used in medicine, the roots as relief for asthma, the leaves as a narcotic. One of its oldest names, vatin-ganah, means anti-wind. It is also thought that eating aubergines reduces blood cholesterol.

Most of the modern research into the aubergine is carried out in the south of France, and if you want to know more you must make your way to Avignon where are the Mediterranean vegetable and fruit gardens of France. Here you will find a dozen fruit and plant research stations run by the French government's Institut National de la Recherche Agromique (INRA). So what exactly have they done to the aubergine? Certainly they have improved its looks in the past 10 years. As for its flavour, they can ensure sure it doesn't reach over-high levels of bitterness.

You can even find out what causes the bitterness if you have a dictionary, a degree in chemistry and the time to scrutinise a learned paper by Serge Aubert, the director of vegetable technology research at INRA's Montsavet station. He explains that the bitterness is due to glyco-alkaloids and steroidic saponins without nitrogen.

What? 'Saponins are like savon, soap,' explains Marie-Christine Daunay, a research technologist. 'They are very close to soap. They can wash away fat.' So there is some truth in the claim that aubergines can help to reduce cholesterol? 'We think so, but it's not yet been proved by studies.'

What is of interest to cooks is that the greatest concentration of saponins is highest in the fleshy placenta around the seeds. Bitterness increases as an aubergine ages; in a young aubergine you won't see the immature seeds at all, but in older ones there are tiny dark pips.

Does the science of the aubergine help the cook? Yes: we should reconsider the fact that most recipes for the aubergine indicate that it should be sliced and salted for an hour, the salt drawing out a proportion of the bitter liquid (or immersed in salted water under a weight). This is something of an old wives' tale, because a century ago old wives couldn't get to a modern supermarket to buy Peter Pan aubergines that never grow old. They often had no choice but to make the most of older aubergines growing in their garden. So they salted them or, after cooking, passed the pulp through a sieve to remove the seeds, and thus the excessive bitterness.

Scientists have another observation which may be of use to the cook: salting the aubergines will reduce the amount of oil they subsequently absorb when fried. The French avoid that problem with the beignet, a roundel of aubergine dipped in batter to form a seal before deep-frying (which gives it a lovely marshmallow texture inside; and the tiny amount of carbohydrate converts to sweetness inside, balancing bitterness).

French scientists offer no culinary advice on the cooking of aubergines. But we can turn to a current best-selling cookery book in France, Voyages de l'aubergine by Nina Kehayan (published by Editions de l'Aube), who is of Armenian origin. She pulls together the strands of aubergine cooking from its beginnings in Asia through the Middle East to Armenia, Turkey, Greece, Italy and eventually Provence, and passes on the benefit of some centuries of aubergine lore. For example, rather than minimise the bitterness of the aubergine, you may prefer a dish that maximises it.

Caviar of Aubergine makes the most of the bitterness. You grill the aubergine whole until it's completely soft (or barbecue or bake it). In the most rustic version you char it over a smoky wood fire outdoors (or, less authentically, a gas flue) to get a fierce, smoky flavour. Hold it with a fork till it is completely blackened outside and soft inside. Then, as it cools, grasp the stem with a cloth and peel off the charred skin. When cool, beat the pulp to a puree, seasoning with salt and pepper and finely chopped garlic; beat in a thin stream of olive oil or sunflower oil as if you were making mayonnaise.

In Armenia, this 'caviar' would be presented on a dish surrounded by sliced hardboiled egg and eaten spread on country bread. Country by country refinements are added; in Turkey tahina (sesame seed paste) might be added, in Greece black olives and lemon juice; in Italy and Provence it may be blended with tomato, skinned, deseeded and chopped to achieve a milder taste. If the puree is too bitter this way, you can make the caviar with steamed or boiled aubergine.

Moussaka is the best known example of the most universal use of aubergines which involves layering them with meat or other vegetables. First the aubergines are sliced lengthwise or into rounds of about 1cm thick, salted and placed in a sieve to drain for an hour. Then rinse them, pat dry with absorbent paper and fry in sunflower or olive oil on a medium heat till completely soft (5 to 10 minutes) and leave them to drain on more absorbent paper. This is the base for dozens of classic dishes: layered with meat, with cheese, with skinned, deseeded tomatoes which have been fried in the oil left from cooking the aubergine. The combinations are then baked in a medium oven.

Given that the aubergine is really a great blotting pad or sponge which takes up other flavours, the Chinese, with their sweet and sour sauces, and Indians, with their spiced curries, have a good understanding of its best uses. Aubergines also lend themselves to pickling, and in the Middle East they make a wonderful sweet jam with baby aubergines flavoured with cumin.

In ratatouille, that Mediterranean classic, the aubergine also acts as a catalyst, adding very little by way of flavour but enhancing all the vegetables around it. For the best results, although this may sound like a counsel of perfection, it really is better to cook each of the vegetables separately (onions, courgettes, green peppers, tomato, garlic, aubergine) because each reaches melting perfection at markedly different cooking times. They should be drained of oil and then combined for just long enough to reheat while you adjust the seasoning. A dish lesser known here is Sicilian caponata (the name derives from the capers used in the dish). This is Nina Kehayan's recipe.

CAPONATA

This Sicilian dish is eaten cold and is best make it the day before.

Serves 6

1lb/500g aubergines, cut into small pieces

1lb/500g green peppers, deseeded, cut into small dice

1lb/500g ripe tomatoes,

skinned, deseeded, chopped or 2 tins of tomatoes, drained, seeds removed

1 heart of celery, chopped

2oz/50g capers

2oz/50g green olives, stoned

half glass red wine vinegar diluted with equal volume of water

1 teaspoon sugar

salt to taste

olive oil for frying

Using a generous amount of oil, fry the aubergines gently for 15 minutes, preferably in a non-stick pan. Remove with a slotted spoon and drain well, then season with salt and set aside. In the same pan, using the same oil, adding more if necessary, fry the green peppers gently for 15 minutes. Drain, season and set aside.

Now fry the onions till they soften, about 15 minutes. Add the tomatoes and cook for five minutes, stirring well to avoid burning. Now add the capers, green olives and celery, and cook for another 12 minutes, continuing to stir.

Finally add the reserved aubergines and peppers, and cook for another 5 minutes. Remove from heat, sprinkle with the diluted vinegar and sugar, mixing it in well. Turn out into a serving dish and leave overnight in the fridge, or at least six hours. Eat with country bread as a lunch dish. -

(Photograph omitted)