What's this
What is isinglass
Fish paste or "ittiocolla" - in English: isinglass - is the vulgar name of an ingredient / additive (E441) based on collagen (protein), with a thickening and gelling function, very common both in home cooking and in industry - food, cosmetics, pharmacology etc.
Read also the nutritional evaluation of isinglass and the gelatin article.
"By definition", isinglass would be obtained by drying and crushing the fish's bladder, but also their cartilages - typical of the Chondrichthyes biological class, to which sharks, stingrays and sturgeons belong, for example. Today, however, the most widely marketed product in Italy, despite being called by the same name, is mainly obtained from the fifth quarter of large land slaughter mammals (mainly pigs, but also cattle), in particular from the skin (commonly known as rind or rind) ) and cartilage.
In Italy, the word "isinglass" is improperly used as a synonym for "edible gelatine"; it is actually a rather gross semantic error, or an imprecision. In fact, as we have said, although it is still produced and marketed, fish collagen has been largely replaced by that obtained from pigs and cattle, better identified as "gelatine sheets". Secondly, currently, most "food jellies" are of vegetable or algal derivation; a typical example is gums, mucilages and other similar polymers. The most common are: guar gum, xanthan gum, tara gum, konjac gum, psyllium cuticle flour, agar agar, pectin, etc.
In addition to the marked thickening and gelling capacity, the main feature that all these products have in common is solubility in water or in any case in hydrophilic compounds; for the rest, they are molecules with chemical-physical properties that are sometimes quite different from each other. There are therefore many differences that make one gelatine rather than another suitable. In practical terms, the choice and application of food jellies can change based on the result you want to achieve - consistency, tolerance to acid or basic pH, color, translucency, tactile sensation etc. - to the nutritional or philosophical needs of consumers - see allergies food, intestinal diseases, vegetarian or vegan diet, Muslim, Jewish, Hindu, Buddhist religion - etc.
Did you know that ...
Most of the worldwide production of isinglass is intended for clarification or refinement of beer and wine. It can also constitute a sort of highly specific "sticky paste".
Nutritional Properties
Nutritional properties of isinglass
For most additives it would be useless to open a paragraph on their nutritional properties. In the case of isinglass instead, it is useful to spend at least a few words on it.
First of all we must specify that, with the exception of allergic forms, there are no documented adverse reactions affecting isinglass or terrestrial animal collagen gelatin. It may seem superfluous but, being a food additive (E441), many consumers are led to believe that at considerable doses it can have a negative influence on health. It is not so.
In fact, isinglass is pure collagen, consisting only of proteins. It supplies approximately 340 kcal / 100 g but, if we consider that about 1 g of pudding is used, its nutritional value, as well as its impact on the diet, are almost null.
Anti-cellulite dessert - Aspic of blueberry and centella asiatica
X Problems with video playback? Reload from YouTube Go to Video Page Go to Video Recipes Section Watch the video on youtubeInstead, a consideration must be given to suitability for philosophical or religious nutritional regimes. All animal jellies are to be avoided in vegetarian diets, in Hinduism and in Buddhism. Those from kosher and halal fish are relevant in Judaism and Muslimism; however, the sturgeon is considered an impure animal and therefore should be avoided. The same abhor the pig but not the cattle, if slaughtered according to certain criteria.
uses
Fish paste in the kitchen
Before collagen was obtained from cartilage and from the skin of land animals, thickeners and gelling agents were made from isinglass. This was commonly used in sweet pastry in many recipes, such as fruit jellies, white puddings - like blancmange - etc.
Actually, food jellies all have the same purpose. However, many know that "thicken" and "gel" are not exactly the same thing. For example, a custard must be "creamy", not simply "dense" and even less "gelatinous". On the contrary, a fruit jam should have a thick consistency, therefore thick, not creamy or gelatinous. And again, talking about a pudding, it is essential that it has the structure and the flickering of a jelly, it must not flake off or even stick to the mold.
Isinglass, or rather all animal collagens, have above all gelatinizing capacity; another example is agar agar. Pectins, on the other hand, lend themselves more to thickening, especially aqueous mixtures rich in sugars. On the other hand, to increase the creaminess, lecithin-rich emulsions of water and fat are particularly suitable.
Animal collagens are not suitable, for example, for jams or even creams. This does not mean that, if used in small doses, they are not able to increase the body of the recipe; on the other hand it is not their primary function.
To get an idea of what the natural consistency of isinglass can be, simply look at the chilled meat broth; if well concentrated and kept at 4-5 ° C, it assumes a typically "trembling" consistency, to liquefy as soon as it is heated. In this case, collagen comes from the connective tissues of the flesh that tend to dissolve with boiling.
Isinglass is also still used to optimize the preservation of certain canned products, both for human nutrition - see meat in jelly - and for animals, such as wet cat food; below we offer a homemade recipe for your four-legged friend.
Moist Food for Cats - Homemade Jelly Meat
X Problems with video playback? Reload from YouTube Go to Video Page Go to Video Recipes Section Watch the video on youtubeFish paste to clarify and refine drinks
The "finings" based on isinglass are widely used in Great Britain as accelerators of precipitation and clarification in the brewing sector. In essence, it is a chemical process that replaces physical microfiltration and as such does not require heat treatments or membranous passages.
The fish glue finings find particular application in the production of raw beers (cask-conditioned or cask ales), although some products not subjected to this processing are still available. Added to the "raw" beer, these flocculate the live yeasts forming a gelatinous mass that tends to precipitate. By avoiding stirring the liquid or otherwise moving the deposit to the bottom, this allows the beer to lighten naturally and faster than normal.
Did you know that ...
Flocculation is a chemical-physical mechanism that involves colloidal systems, in which the solid phase tends to separate forming flakes in suspension.
Non-cask beers on the other hand are generally pasteurized, which allows rapid precipitation with deposit, easily removable by physical filtration. Obviously, the heat treatment alters the organoleptic and gustatory characteristics of the beer, and kills the yeasts.
The use of isinglass in the production of raw beers is currently decreasing, although it is a rather effective method to recover the most impure lots.
Although in the finished beer only traces of isinglass can be identified, many vegetarians consider these drinks - today still very widespread, especially in the United Kingdom - unsuitable for their diet. Therefore a vegetable alternative has been proposed, in an attempt to reproduce the same clarifying power; this is the case of carrageenan extracted from the crispus or carragheen crondo (Genus Chondrus and crispus species), a type of red algae. This polysaccharide is used both during the thermal process and after fermentation, but above all reduces the concentration of the suspended protein mass and not that of the microorganisms. In contrast, isinglass is mainly used to remove yeasts. Since the two clarifying agents act differently, to the detriment of vegetarians, in reality they are not interchangeable and many beers both use them.
The fish glue finings are also used in the production of kosher wines - that is allowed by the Jewish religion - even if for reasons of kashrut they cannot derive from the beluga sturgeon, considered impure and therefore not kosher.
Fish glue as a food preservative
Isinglass was used as a preservative in the 1940s, before and during the Second World War, especially in Great Britain. It was dissolved in water, typically in a bucket, into which fresh eggs were immersed.
Fish glue as a preservative for parchments
Isinglass is used for the restoration of parchments. After soaking in water and cooking at 45 ° C, with the addition of decanted tragacanth gum (emulsifier), a very useful compound is obtained to repair the flaked paint of these manuscripts - previously softened with ethanol. This can be applied directly to the point, in very small drops, which are then guided with the help of a binocular microscope, under the edges of the flaking paint.
Isinglass can also be used to coat the fabric itself. Here, the isinglass is applied superficially and has the characteristic of being able to be reactivated with humidity, for example with an ethanol-water mixture. For this use, it is usually cooked with a few drops of glycerin or honey. This adhesive is advantageous especially in situations where you want to use very little water. It also has greater adhesive strength than many other products used to repair parchments.
History
History of isinglass
Although it was originally produced exclusively from the "beluga" sturgeon (Genus Huso and huso species), typical of the seas and rivers located in north-east Euro-Asia, in 1795 William Murdoch introduced the use of cod, more available and cheap. From then on, especially in Great Britain, cod isinglass replaced the imported Russian glue.
Curiosity
The etymological origin of the term is most likely related to the Dutch noun "huizenblaas", now considered obsolete. "Huizen" is the name of a species of sturgeon, while "blaas" is the term that defines the swim bladder. In German, "hausen blas" has essentially the same meaning.
