A glance at the latest list of the world's best restaurants reveals that the top eateries are dominated by pioneers of molecular gastronomy.

Two of the top three restaurants in S. Pellegrino's World's 50 Best Restaurants guide include molecular heavyweights Heston Lumenthal's Fat Duck and icon of the Spanish molecular movement, El Bulli in Madrid.

Molecular gastronomy can be briefly defined as cooking using scientific techniques and research. It uses physical and chemical processes - the rearrangement of atoms that occur while cooking - to deliver fine cuisine. There can be a lot of special equipment.

In recent years molecular gastronomy has become something of a maligned food movement.

Does fiddling with food actually make it better or is it just an ego exercise for a chef wanting to showboat their latest cooking technique, ask some critics.

Many, including molecular chefs themselves these days, say the focus should be on the quality of the produce rather than technical contortions of the chef.

One of Shanghai's forerunners in molecular gastronomy, Paul Pairet, says focus on technique for technique's sake is old hat. He himself has moved away from a focus on molecular technique, closing his molecular-styled Jade on 36 and opening Mr & Mrs Bund, a modern French eatery.

"It's not my original intent to distract the diner's attention from the original food taste to the way of cooking," he says when describing his cooking style in an interview.

"What I do is just take the roots of the cuisine in the past to build today the cuisine of tomorrow."

Taking apart traditional cooking methods to discover the science behind them and add precision to rustic techniques has become a foundation of the modern molecular approach.

Molecular techniques can be found in even a country fair with cotton candy.

In Shanghai diners can have their molecular cuisine served with avant-garde fanfare or they can find it built into the arsenal of many a Western chef designing menus in the city.

While it has now become mainstream, molecular gastronomy is a field originated in the 1990s. At that time, Nicholas Kurti, a Hungarian physicist at Oxford and famous gourmand, explored the scientific secrets behind food - exactly why and how it tastes, smells and feels as it does.

In his words, "It is a sad reflection on our civilization that while we can and do measure the temperature in the atmosphere of Venus we do not know what goes on inside our souffl??s." The secret of souffl??s was finally discovered, an enzyme notably found in pineapple that can made food soft and fluffy.

Practitioners use some physical and chemical ways, utilizing ammonia and controlling temperature for example, to obtain precise results and improve taste and texture. They deconstruct the molecules of ingredients and reconstruct them.

But molecular cooking dates back to ancient times, notes Chef Paul at Mr & Mrs Bund. He cites yeast fermentation and the rising of bread - but the atomic structure is understood and controlled.

Proponents say tastes and textures can be multiplied and manipulated - it's possible, for instance, to create orange-flavored pasta. Some note that smaller food molecules mean that food is more easily absorbed and metabolized.

Critics note that some molecular chefs are not cooking but running experiments and they're more like scientists without intuition, losing touch with the basics. Old-school Spanish chef Santi Santamar'a expresses concern over food safety, noting that additives such as alginate jelly and liquid nitrogen are used.

Some, like famous Hong Kong gourmand Au Yeung Ying Chai, take a more balanced view, both praising scientific knowledge but saying it's no substitute for a chef's personal feelings.

After all, romance, variety and imagination are important.

Here are a few examples of molecular cooking - cotton candy (a traditional food reviving childhood memory), a dessert, a fog-like cocktail and a fois gras cigarette. Cotton Candy

Spun sugar - magically light, soft and sweet - occupies a special place in childhood memories. Sticky, transparent sugar syrup is whipped up into balls of cotton that look like puffy clouds in the sky.

Biting into the billowing sugar, there's not much substance but an intriguing sweetness.

Cotton candy is produced in a machine that heats colored sugar, breaking the sugar molecules apart, turning the sugar liquid, and then spinning it. Centrifugal force from the spinning head forces the sugar outward from tiny holes in the head and it solidifies in the cooler air.

Cotton candy is often associated with summer but it's pleasant in winter and revives childhood memories.

Price: Cotton candy 5 yuan

Venue: Shanghai No.1 Food Store

Address: 1/F, 660 Handan Rd

Foie Gras Can't Quit

The dish looks avant-garde - it's shaped like a red cigarette with ash at the tip and served on a white dish that looks like an ashtray. The foie gras is inside and the red "paper" exterior is made with red crystallized raspberry juice.

The creator, chef Paul Pairet of Mr & Mrs Bund, says the foie gras has been injected into the "cigarette." He discovered that a molecule in raspberry helps crystallize the juice in a dry environment.

The dish has a fresh and complex texture. The outside is brittle and crunchy while the inside is smooth and creamy. The cigarette "ash" is made of ground ginger, truffle and other ingredients. The idea is to pick up the cigarette and dip it in ash, for a rich and balanced flavor.

Chef Pairet, who's known for culinary showmanship, says molecular manipulation is only one part of the cooking process - the whole purpose is to improve the flavor and texture of food.

This cigarette dish cannot be ordered at this time, but will be offered at his future dining venues.

Egg'wich

THIS sandwich is made of egg yolk, arugula-raclette pesto, onion microgreens and buttered toast. This is a whole different egg yolk. The texture is between that of a well-cooked egg and a soft-boiled egg. It tastes very creamy and smooth, a little like cream. Chef Leo Yao explains that he puts a whole raw egg into water heated to exactly 65 degrees Celsius - precise temperature is the key. The egg yolk solidifies while the white remains liquid. Then the yolk and white are separated and the egg is made into a sandwich.

Chef Leo says that compared with Chinese cuisine, Western cooking is more precise. "Even seasonings, like sugar, salt and flour, should be weighed accurately to the gram with a rigorous scientific attitude," he says.

Le Flora Fixe

This showy, vapory and very fragrant molecular cocktail turns icy Sauvignon Blanc into mist in a concoction devised by bar manager Ryan Noreiks. The other ingredients are Corralejo silver tequila, elderberry flowers, absinthe and citrus.

The wine is added at the very end, to top it off, when Sauvignon Blanc is poured over dry ice in a cocktail glass.

A strong fruity fragrance rushes upward to be inhaled. The taste is smooth and balanced since the flavor of elderberry offsets the strong tequila. Noreiks says the molecular aspect - dry ice - generates the intriguing scent. "Whether in food or cocktails, smell plays a very important role. Fog is a perfect way to present smell."

Price: Egg'wich 58 yuan,

Le Flora Fixe 70 yuan

Venue: Alchemist

Address: Block 32, 45 Sinan Rd

Ice Cream Bomb

An exploding ball of cherry flavor is the creation of dessert chef Miller Wang. It's ice cream with an unusual cherry on top.

The solid cherry is a transparent red ball that explodes into cherry juice when placed in the mouth. The slightly sour cherry combines with the milky sweet ice cream to create memorable molecular commotion.

The secret of how the solid cherry suddenly liquifies is the addition of glucose and alginate (a sodium salt found in many brown seaweeds).

Chef Miller says molecular gastronomy takes a lot more time and energy, which is fine once in a while, but isn't cost-effective.

Diners who would like to try this taste sensation should order in advance.

Price: Ice Cream Bomb, 88 yuan

Venue: Aux Jardins Massenet

Address: 51 Sinan Rd