Molecular Gastronomy plays with established food identities to challenge the semiotics of food. It explores the use of chemicals and processes previously the domain of high-throughput industrial food producers and food scientists to deliver non-intuitive gastronomic experiences.
Our expectation than an egg yolk contains egg is flipped and inverted when one bites into one of Ferran AdriÃƒÂ ‘s encapsulated broths, extractions, or infusions. Instead of egg yolk, when one bites down and pops the membrane, mango essence may bloom onto your palate. Food hack for food play.
A lot of the “food hack” aspects of Molecular Gastronomy flows from the transformative effects of a few certain ingredients, or reagents as we would call them in the lab.
One key reagent is Xanthan Gum.
So, what is this xantham gum you speak of?
Xanthan gum (shown at top) is a polysaccharide, meaning that it is a large molecule composed of several saccharides or sugars linked together. The size and shape of this molecule dictates how it interacts with it’s environment, chemical and physical. Xanthan gum has several interesting qualities that makes it very useful in the mega-food industry and also in molecular gastronomy.
Some of those qualities are:
it helps with the creation of foams
it retards or controls the formation of ice crystals
In particular, the one characteristic of xanthan gum that makes it so valuable is something called pseudoplasticity or thixotrophy.
Believe it or not, you have experienced thixotrophy. Yes, you have, I promise.
When you start to shake a bottle of ketchup, the goo inside pretty much stays put (while your fries are cooling into an unappealing mass of transfats). As you whack on it, it begins to experience something call sheer. The molecules in the ketchup are whipped past one another (shear) and the ketchup and the xanthan gum, and other similarly reacting chemical species, dynamically and temporarily liquefies. Once it shoots out onto your plate or fries or whatever needs ketchup, it is no longer experiencing sheer and returns to its thicker more viscous state. If it were not for this thixotropic behavior, we would need to buy ketchup in jars like peanut butter and use a knife.
You can see experiments on thixotrophy by NASA at their NASAexplores site.
In the industrial setting, it is desirable to have and maintain thickness (viscosity) during production, storage, and shipping, while also delivering a product that is not TOO heavy in the mouth. I think that what they mean is, to put a less than fine point on this, that its thick without being snotty.
It is often mixed with guar gum because they work synergistically to boost the thixotrophic qualities of food or liquids.
So where does this artificial stuff come from anyways?
Well, its actually the by-product of a bacterium called Xanthomonas campestris. In the 1950’s, the USDA ran a large project to scan for organisms that produced interesting biopolymers. One of those biopolymers that they found was xanthan gum.
What sorts of foods have xanthan gum in it?
(Borrowed from ADM)
How is it used in Molecular Gastronomy?
Xanthan gum is added to “your favorite food/liquid” to change it into a gel, thick paste, gloopy mix, or foam. If your are whipping up carrot clouds, you may want to pitch in some xanthan gum to stabilize the loft of the foam. If you want that mango puree to be more viscous when you make it into mango-yolks, add some xanthan gum and, voila, its thick and stabilized.
How is it used in Gluten-Free baking?
If you have ever made your own bread, you would appreciate the magic that wheat gluten brings to the party. It is what gives the stretch to the dough and is that which allows bubbles to form in the bread as gases are produced by the yeast. Without gluten, the gases are not trapped into gluten surrounded bubbles, and the bread is flat and, well, not really bread-like at all. Obviously, gluten-free means you do not have gluten. Xanthan gum replaces gluten by providing the viscosity to the batter to trap the gases, forming the airy texture you want in bread.
This has been a quickie introduction to xanthan gum. There are some fun links through out this post that you might want to explore.
Molecular Gastronomy sites of interest:
Sources for Ingredients: