Some chefs are now bent on applying principles of chemistry and physics to develop novel foods and flavours. Some call this “molecular gastronomy,’ a term that was coined by physicist Nicholas Kurti and chemist Herve This back in 1992 to describe a discipline that would focus on the scientific investigation of cooking. Basically the kitchen was turned into a chemistry lab where temperature controlled baths, vacuum chambers, rotary evaporators and ultra-cold liquid nitrogen were used to study the reactions involved in cooking with a view towards producing improved textures and flavours as well as serving up unique dishes. A number of chefs jumped on the bandwagon and proceeded to crank out fascinating dishes as they embraced the application of science in the kitchen. Ferran Adria’s El Bulli in Spain and Heston Blumenthal’s Fat Duck in England became celebrated restaurants where instead of dining on regular fare, customers were served “sardines on toast” ice cream and fruit caviar.
So what is fruit caviar? Little spheres that look like caviar and gush fruit flavor as they burst in the mouth. There’s a lot of neat chemistry here and it all starts with using a sodium carbonate solution to extract sodium alginate from the cell walls of brown algae. Alginates are carbohydrates composed of polymers of the simple sugars mannuronic and guluronic acids and have two interesting properties. When added to sauces, milk products or salad dressings they have a thickening effect. But when it comes to molecular gastronomy it is their property of forming a gel on contact with a solution that contains calcium ions that allows for a unique features referred to as “spherification.”
Sperification has been a big hit ever since it was introduced by chef Ferran Adria. Basically it involves mixing sodium alginate with fruit juice to form a thick solution. Then using a syringe filled with the thickened juice, droplets are discharged into a calcium chloride solution. As soon as the juice hits the calcium chloride solution, it forms little spheres that can be removed with a serving spoon. Adria also developed a method of making lychee noodles by filling a syringe with lychee juice and alginate and then tracing zigzagged laces over a calcium chloride solution.
Foams are also popular in molecular gastronomy. A foam is a substance that is formed by trapping many gas bubbles in a liquid or solid and its formation is enhanced with the use of a foaming agents such as soy lecithin which inhibits the coalescence of the bubbles. For example pureed beets can be mixed with lecithin and whipped into a pretty red foam that can be used to top potatoes or even meat with an unexpected taste.