Turns out if I follow the emulsion trail a bit there are more clues about binding.
An emulsion is typically about fat and water – one dispersed in the other and they don’t like to stay together, hence they need an emulsifier like eggs or dairy to keep them joined. Sure you can create an oil and water emulsion like a vinaigrette, but that will separate over time. An emulsifier would keep the disparate parts from separating. But too much of an emulsifier can be a bad thing. A stabilizing agent, typically a starch, is necessary to keep the emulsifier from repelling against each other.
So examining “binders” we have fat and perhaps some liquid in the meat, an emulsifier like eggs and dairy containing protein as well as liquid and finally starch in the form of breadcrumbs acting as a stabilizer. Quite the handsome quartet!
That the meat itself contributes to the emulsion didn’t occur to me until I read a post on why fresh ground turkey burgers fall apart during cooking. Fresh hamburger patties don’t suffer from this – you can make stable patties that don’t fall apart just by pressing the meat together. Turkey on the other hand doesn’t have the fat content of ground beef so they can’t form stable patties. Adding salt to denature the proteins in the turkey and a little oil promote better cohesion.
All this got me interested in a little experiment. Given that seafood has even less fat than turkey, I wondered if just adding oil and salt would be enough to make stable patties. Turns out it won’t. Adding salt and some olive oil to a package of salmon didn’t yield substantially more cohesive patties than the salmon alone. Even adding breadcrumbs didn’t help much. Granted I didn’t let them sit for very long but the mixture wouldn’t hold together at all. Since I had very little salmon (7 oz) for this experiment I didn’t want to crack an entire egg on it. Instead I used dairy – heavy cream in fact – and just like that I had a stable patty! I could tell from the moment I stuck my hand in it that it would hold together.
Turning to On Food and Cooking page 628, I read that:
The yolk proteins in eggs and the casein proteins in milk and cream are the best protein emulsifiers.
I guess On Food and Cooking did cover the topic after all – I just needed to look in the right place! It also means that dairy/cream at the mix stage does contribute to binding by acting as an emulsifier.
In looking at this fat-liquid-stabilizer-emulsifier quartet that make up “binders” in meat mixtures, it’s no wonder tables and ratios don’t exist. Too much depends on the fat content of the meat, the amount of liquid in it, the type of stabilizer and how much it can absorb, not to mention the type of emulsifier and the other ingredients in the party, i.e. salt, acid, etc. It is defiantly a touchy/feel-y process.
