Cooking for Geeks: Real Science, Great Hacks, and Good Food (63 page)
Read Cooking for Geeks: Real Science, Great Hacks, and Good Food Online
Authors: Jeff Potter
Tags: #COOKING / Methods / General
One of the more unexpected food additives is
transglutaminase
, a protein that has the ability to bond glutamine with compounds such as lysine, both of which are present in animal tissue. In plain English, transglutaminase is “glue” for proteins.
Transglutaminase isn’t used to change the texture of foods or to modify sensations of flavor. Rather, the food industry uses it re-form scrap meats into large pieces (McNuggets!). You didn’t actually think that gorgeous hunk of ham at the deli counter was one piece of meat, did you? From the rare boneless pig?
Transglutaminase is also used to thicken milk and yogurts by making their proteins longer in the same way that adding longer polysaccharides in gelling applications makes things thicker. Additionally, it is used to firm up pastas, to make breads more elastic (able to stretch without tearing), and to improve gluten-free breads for those with celiac disease.
For food hackers, though, the compelling opportunities for transglutaminase reside primarily in meat-binding applications. Food hackers have, of course, seized the opportunity to use it to make Frankenstein meats (all in the name of fun). You can “glue” white fish to red fish, make a turducken (a turkey-duck-chicken dish) that holds together, and make a heat-stable aspic, relying on transglutaminase instead of heat-sensitive gelatins or aspics.
The recipes that follow will give you some starting ideas, but really the concept of “meat welding” can apply to any meats that you want to stay together, including fish and poultry. You can glue scallops together in a long chain, wrap chicken around fillings (binding the chicken to the other end of itself), and wrap bacon around scallops.
The reaction occurs at room temperature and takes around two hours to set, so plan ahead. Use about 1% transglutaminase for the total weight of your food. You can sprinkle it dry on the food item or create a slurry (2 parts water to 1 part transglutaminase) and brush it onto the surfaces to be glued. Once adhered together, let the join rest for at least two hours; otherwise, you will shear and break the bonds as they’re setting.
Chicken and steak bonded together with transglutaminase. Mmm, Doublemeat Palace!
Keep in mind that, because
you’re
made of protein, you should take care to not get it on your skin or inhale the powder. Unlike real glue, transglutaminase is actually a chemical catalyst that literally bonds the two sides together at a molecular level. Gloves and a respirator mask are good insurance. Since transglutaminase is a protein itself and has the same structures as the amino acids it binds, it’s also capable of binding to itself. After a few hours at room temperature, though, it loses its enzymatic properties, so it’s not a huge deal if you spill a bit on your work surface. Once opened, store it in your freezer to slow the rate of the binding reaction.
Instructions for use. |
Note Try vacuum-packing the food. This will improve the fit between the two pieces of meat. |
Uses. |
Origin. |
Chemistry. Transglutaminase acts as a catalyst on glutamine and lysine, causing the atoms composing the two groups to line up so that they form covalent bonds. Note A covalent bond is one in which two atoms share an electron, resulting in a lower energy state. Electrons are “lazy” in the sense that they prefer states that take less energy to maintain. To visualize the reaction, imagine spreading apart the fingers of your left and right hands and touching the tips together, left thumb to right thumb, left pinky to right pinky, etc. Without some amount of coordination, getting the atomic “fingers” to line up just doesn’t happen. Transglutaminase helps by providing the necessary atomic-level guidance for the two groups to touch. And once they touch, they can form covalent bonds and stick. Continuing the finger analogy, it’s a bit like having superglue on your fingers: once they are lined up and are touched together, they stay together. |
Before interaction, strands of proteins with glutamine and lysine groups are unattached (left); after interaction, the glutamine and lysine groups are covalently bonded wherever transglutaminase has a chance to catalyze. Note that transglutaminase itself does not remain as part of the bond after the reaction.
While you can pull apart items joined with transglutaminase, the individual meats themselves may be weaker than the join.
Technical notes | |
|---|---|
Concentration | ~0.5% to 1% of meat weight. |
Notes | Cold-set for at least two hours — that is, apply to meat and let rest in fridge for two hours. Reaction time is correlated with temperature, so it takes longer to set at colder temperatures. |
Temperature | Heat-stable once set. |
It’s cool to see bacon-wrapped scallops where the bacon just sticks to the scallop. It’s also a good example of how to work with transglutaminase.
In a small bowl, mix roughly 2 parts water to 1 part transglutaminase to create a slurry.
On a small plate that will fit in your fridge, lay out:
- 8 scallops as large and as cylindrical as possible, patted dry
- 8 slices bacon, cut in half so that they can wrap around a scallop one time
Using a brush, coat one side of each piece of bacon with the slurry. Place a scallop on the bacon and roll the bacon around the scallop. Repeat for each scallop and transfer to the fridge for at least two hours to allow the transglutaminase to set.
After resting, the bacon should be well adhered to the scallops.
Preheat your oven to 400°F / 200°C.
Place the scallops in a hot frying pan lightly coated with oil or a small amount of butter, with one of the “exposed” ends down. This will cause a Maillard reaction and develop a nice layer of flavor on the scallops. After a minute or so, flip the scallops over so that the other exposed side is in contact with the pan and immediately transfer your frying pan to the oven.
Finish in the oven for about five to eight minutes, until the bacon is done and the scallops are cooked.
Note
- Use only an oven-safe frying pan in your oven. Some commercial frying pans have silicone handles — typically blue — that are oven-safe.
Use a brush to coat one side of a strip of bacon with transglutaminase. (If you don’t already have a pastry brush, consider getting one made with plastic bristles, because that type will not leave strands behind.)
Carefully roll the bacon around the scallop. The transglutaminase will not bond instantly, so you will need to pinch and press the items together. Let set for two hours in the fridge.
Pan sear the scallops on high heat, flip to sear on both sides, and transfer to the oven to finish.
A cross-sectional slice of the finished product shows the joined surface of the bacon and the scallop. (Shown on top of a leaf of bok choy.)
