The final step is to cook the whole mixture at a low temperature, which strips the fat coating from the starch grains. They then take on water, swell and rupture, releasing their glutinous content and evenly thickening the liquid. So no lumps. The fat is still there, but it is spread out in such tiny globules that they can’t coalesce into puddles. So no grease.
What is the chemical makeup of chicken skin? How bad for you is it, nutritionally, if the fat beneath it has been rendered during cooking?
In recent years, chicken skin has been scorned as a nutritional bete noire, along with salt, sugar, saturated fats and virtually anything that has been refined by human intervention. The abominable boneless, skinless (and may I add tasteless) chicken breast has become ubiquitous.
I can understand ditching the bones, but I and many other people insist that the skin is the best thing about a roasted chicken or turkey, in terms of flavor and texture.
Raw chicken skin consists of about 13 percent protein, 32 percent fat and 55 percent water. Turkey skin is 13 percent protein, 39 percent fat and 48 percent water. Those components are arranged, as in many other animals (including us mammals), in three layers of cells: the outer epidermis, the middle dermis and the inner hypodermis. The proteins, mainly collagen, elastin and keratin, are distributed throughout the layers in different amounts: collagen and elastin mostly in the dermis and the fat (adipose) cells mainly in the hypodermis. Elastin makes the skin somewhat rubbery. It is actually stretched over the bird’s body under tension, like a wet suit on a scuba diver.
The fat, of course, is the source of some people’s nutritional concern. According to the USDA, raw chicken fat contains 9 percent saturated, 14 percent monounsaturated and 7 percent polyunsaturated fatty acids. (Turkey: 11 percent saturated, 15 percent monounsaturated and 12 percent polyunsaturated.) This works out to about 3 grams of saturated skin fat per pound of whole chicken. An ounce of the skin of turkey has 3 grams of saturated fat. During roasting, much of the fat is rendered and drips to the bottom of the pan, so by the time it gets to the table, there’s even less fat in the skin.