Molecular Gastronomy – The Food Science

When the art of selecting, preparing, serving and enjoying good food becomes the science of doing so.

The way of preparing food did not change much through history. Kitchens are equipped with basically the same tools that cooks used centuries ago. If you are like me you have heard about molecular gastronomy and was intrigued but never took the time to actually find out what exactly it is. Two Oxford physicists, Nicholas Kurti and Hervé This, coined the term in 1988. Formally it refers to the scientific discipline that studies the physical and chemical processes that occur while cooking. Apart from this, molecular gastronomy also incorporates the social and artistic components. It is distinct from the traditional food science, which is focused on food production on an industrial scale, nutrition and food safety. Until the establishment of molecular gastronomy, there was also no scientific discipline studying the chemical processes of cooking at home or in the restaurants – as opposed to food preparation for the mass market.

Today the term is very often connected with chefs wielding liquid nitrogen, pipettes, edible gels, blowtorches and other equipment usually used in a laboratory. Molecular gastronomy also studies heat conduction, convection and transfer, physical aspects of food/liquid interaction, stability of flavor, solubility problems, dispersion, and texture/flavor relationship. Understanding the science of cooking can lead to seemingly bizarre dishes that are unexpectedly delicious. Very often it is all about integrating what is already known into something totally new. Some examples of molecular gastronomy foods are a miniature apple that is made to taste like meat, cocktails in ice spheres, fake caviar made of olive oil, transparent raviolis, spaghetti made from vegetables, instant ice cream and many others.

Though molecular gastronomy is based on science it is still a mix of science and art of cooking. The scientific component is best understood if we look at techniques, tools and ingredients used for cooking which are summarized at the end of this article.

Spherification of apple juice, Photo credit: jlastras / Foter / CC BY

One technique is spherification which is a nice example of the knowledge transfer from the science laboratory into the kitchen. It relies on a simple gelling reaction between calcium chloride and alginate. For example, to make apple caviar, you first mix calcium chloride and apple juice. Then you mix alginate into water and allow the mixture to sit overnight to remove air bubbles. Finally, you delicately drop the calcium chloride/apple juice mixture into the alginate and water. The calcium chloride ions cause the long-chain alginate polymers to become cross-linked, forming a gel. In laboratory this technique is used to encapsulate cells or provide cell carriers for cell culture.

One of the goals of molecular gastronomy is also to debunk the old cooking myths. For example adding oil to boiling water prevents pasta from clumping. Not true. Why? Because oil and water do not mix, which means the oil stays on the surface, far from the cooking noodles. Instead, add a tablespoon of something acidic, such as vinegar or lemon juice, which inhibits the breakdown of starch and reduces stickiness. 

From the scientific perspective cooking can be viewed as molecules obeying well-known processes that describe the behavior of all solids, liquids and gases. But the reactions that make food taste good or bad are still not very well understood. So for now we still have to rely on the traditional recipes and our sense of taste and smell, instead of only following the scientific protocols.

Molecular gastronomy techniques, tools and ingredients  

Techniques

• Spherification – for producing a caviar-like spheres with new flavors (apple, olive oil …)
• The use of emulsifiers
• Aromatic component – gases trapped in a bag, a serving device, or the food itself
• Whimsical or avant-garde presentation style
• Unusual flavor combinations, such as combining savory and sweet and flavor juxtaposition
• Flash freezing
• Creating new food textures (gels, foams, glass like food)
• Cooking in a microwave for creating dishes that are cold or even frozen on the outside with a hot liquid in the center
• High pressure cooking
• Improved temperature control
• High-power mixing and cutting machines for example ultrasonic agitation to create emulsions

Tools

• Liquid nitrogen, for flash freezing without allowing the formation of large ice crystals. Also used for freezing and shattering
• Anti-griddle (chilled metal top), for cooling and freezing
• Well controlled water baths for low temperature cooking
• Food dehydrator
• Centrifuge
• Syringe, for injecting unexpected fillings
• Ultrasound
• Vacuum machine
• Pressure cookers
• pH meters
• Tabletop distilleries

Ingredients

• Gelling agents like methylcellulose
• Sugar substitutes
• Emulsifiers like soy lecithin and xanthan gum
• Non-stick agents
• Enzymes, for example transglutaminase – a protein binder, also called meat glue
• Carbon dioxide, for adding bubbles and making foams
• Hydrocolloids such as starch, gelatin, pectin and natural gums – used as thickening agents, gelling agents, emulsifying agents and stabilizers, sometimes needed for foams

References:

Herve This is still posting regular cooking and analytical challenges in the Analytical and Bioanalytical Chemistry journal (link to the last one, you can find the rest on PubMed). Check them out, send a solution and you might get a reward.

Barham P, Skibsted LH, Bredie WL, Frøst MB, Møller P, Risbo J, Snitkjaer P, Mortensen LM. Molecular gastronomy: a new emerging scientific discipline. Chem Rev. 2010 Apr 14;110(4):2313-65.

This H. Food for tomorrow? How the scientific discipline of molecular gastronomy could change the way we eat. EMBO Rep. 2006 Nov;7(11):1062-6.

By Mojca Jez, PhD, Researcher at the Blood Transfusion Centre SI