Isinglass or "ittiocolla" - in English: isinglass - is the vulgar name of an ingredient / additive (E441) based on collagen (proteins), with a thickening and gelling function, very widespread both in home cooking and in industry - food, cosmetic, pharmacological, etc.
Also read the nutritional evaluation of isinglass and the article on jellies.
Shutterstock"By definition", isinglass would be obtained from "drying and crushing the swim bladder of fish, but also of their cartilages - typical of the biological class Chondrichthyes, to which sharks, rays and sturgeons belong, for example. product mostly marketed in Italy, despite being called by the same name, is mainly obtained from the fifth quarter of large land mammals for slaughter (mainly pigs, but also cattle), in particular from the skin (commonly known as rind or rind) and from the cartilages .
In Italy, the word "isinglass" is improperly used as a synonym for "food gelatin"; it is actually a rather gross semantic error, or an imprecision. In fact, as we have said, although it is still produced and marketed today, fish collagen has been largely replaced by that obtained from pigs and cattle, better identified as "gelatin in sheets". Secondly, currently, most part of the "food jellies" is of vegetable or algal derivation; gums, mucilages and other similar polymers are a typical example. The most common are: guar gum, xanthan gum, tara gum, konjac gum, flour of psyllium cuticle, agar agar, pectin etc.
In addition to the strong thickening and gelling capacity, the main feature that all these products have in common is their solubility in water or in any case in hydrophilic compounds; for the rest, these are molecules with chemical-physical properties that are sometimes quite different from each other. There are therefore many differences that make one gelatin suitable rather than another. In practice, the choice and application of food gelatins can change according to the result to be obtained - consistency, tolerance to acid or basic pH, color, translucency, tactile sensation etc - to the nutritional or philosophical needs of consumers - see food allergies, intestinal diseases, vegetarian or vegan diet, Muslim, Jewish, Hindu, Buddhist religion - etc.