By Harold McGee
The simplest deconstructed version of fruits and vegetables is the puree, which includes such preparations as tomato and apple sauces, mashed potatoes, carrot soup, and guacamole. We make purees by applying enough physical force to crush the tissue, break apart and break open its cells, and mix cell innards with fragments of the cells’ walls. Thanks to the high water content of the cells, most purees are fluid versions of the original tissue. And thanks to the thickening powers of the cell-wall carbohydrates, which bind up water molecules and get entangled with each other, they also have a considerable, velvety body—or can develop such a body when we boil off excess water and concentrate the carbohydrates. (Potatoes and other starchy vegetables are a major exception: starch granules in the cells absorb all the free moisture in the tissue, and are best left intact in unbroken cells so the solid puree doesn’t become gluey. See the discussion of mashed potatoes.) Purees are made into sauces and soups, frozen into ices, and dried into “leathers.” For purees as sauces.