Last night I went to one of the
Science & Cooking lectures at Harvard (thanks again to
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bbbsg!) on the topic of
meat glue (aka transglutaminase), with guest speaker Wylie Dufresne of
wd-50, who is a good speaker with a sense of humor and fun.
There was an intro by a professor whose name I failed to catch. He discussed what students in the associated food science class have been working on, discussing flavor compounds (which are developed by time or temperature, depending on the application), and a brief digression to Brillat-Savarin, especially the
aphorisms at the beginning of
The Physiology of Taste (my favorites of the ones I hadn't seen before: XIV and XX). He then introduced transgluaminase as an enzyme that binds proteins together. It is naturally occurring, with the commercially available forms of it derived from soil of some sort. It forms a covalent cross link between two amino acids, glutamine and lycine, though like other proteins, it denatures when heated to a certain temperature, in this case, about 60 C. The time for bonding depends on the temperature as well: it's slower in cooler temperatures, but still works.
Wylie Dufresne talked about the experiments they've been doing at his restaurant; he started this establishment partly to continue his culinary education, and it seems that there's quite a lot of experimentation and play, which sounds like a lot of fun (and totally made me want to have access to a professional kitchen :-). He discussed using meat glue (which is the term he prefers, since it's very descriptive) to put proteins together. Their explorations started with meats, poultry, and fish, since those are the easiest to bind (though some high-fat cuts are more difficult to glue reliably, apparently). They've found that a slurry of meat glue works better than sprinkling it on, since it's more even coverage, and putting salt into the slurry helps bind as well (other spices can be added for flavor). He showed a video of making shrimp noodles, which were pretty much shrimp, meat glue, and flavorings extruded into water; it was fascinating to watch (and of course, I wondered about doing the same thing with kosher fish). Another video showed using meat glue to put two skirt steaks (I think? two long flat pieces from around the diaphragm area) together to make a thicker piece. A third video clip showed how to cut a cod fillet into long strips, binding them together into a sausage shape with meat glue (and much plastic wrap) that was easily sliced but kept much of the fillet texture; when I get a fish share again, I'd love to try this! Also discussed: putting very different sorts of proteins together can be tricky if their cooking times and temps are very different.
Meat glue also works well with gelatin, so they experimented using gelatin with non-proteins to give the meat glue something to bind with, resulting in alternating strips of carrot and celery, or apple and pear, both of which would stay together when heated or caramelized (or both). We also saw barley cooked in meat broth, then meat glue added, to make it into a solid loaf. Some of the other fascinating experiments included tofu that had been beaten with Campari, then reglued together with meat glue, and it held: Campari tofu! Or the peanut butter that had been mixed with meat glue, then made into sheets, which were cut up after they solidified: they acted like pasta both for twirlability and heatability, like a farinaceous noodle.
He mentioned that there is one Japanese company, Ajinomoto, that offers meat glue, and are different formulations that are best for different applications (Activa GS works well with fish, for instance). When I went looking, it seems that the only formulation of meat glue that's kosher certified is Activa TIU. Also, "Ajinomoto offers Activa to individuals in 1 pound increments. A kilo currently costs roughly $60 and will glue over 100 pounds of meat paste and a substantially larger amount of whole muscle pieces. Activa is also available through some online retailers. Activa is not pure TG, as the pure form is too concentrated to use easily. Instead, Ajinomoto blends TG with fillers (maltodextrin, a break-down product of starch) and other functional ingredients to suit the end needs of the user." (from the article linked to above). Which makes me want to buy a pound of the kosher stuff and start playing...
