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.
“By definition,” isinglass would be obtained from drying and crushing the swim bladder of fish, but also from their cartilage – typical of the biological class Chondrichthyes, to which sharks, rays and sturgeons belong, for example. Today, however, the most marketed product 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 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, at present, most of the “food jellies” are of vegetable or algal derivation; typical examples are gums, mucilages and other similar polymers. The most common are: guar gum , xanthan gum , tara gum, konjac gum,psyllium , agar agar , pectin etc.
In addition to the strong thickening and gelling capacity, the main characteristic 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 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 desired result – 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 dietreligion, Muslim, Jewish, Hindu, Buddhist – etc.
Did you know that …
Most of the world production of isinglass is destined for the clarification or refinement of beer and wine . It can also be a kind of highly specific “glue 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 gelatin instead, it is useful to say at least a few words about it.
First of all we must specify that, except for allergic forms , there are no documented adverse reactions affecting isinglass or gelatin based on terrestrial animal collagen. It may seem superfluous but, being a food additive ( E441 ), many consumers are led to believe that in large doses it can have a negative influence on health. It is not so.
In fact, isinglass is pure collagen, consisting only of proteins. It provides about 340 kcal / 100 g but, if we consider that about 1 g portion of pudding is used, its nutritional value, as well as its impact on the diet, are almost nil.
Anti-Cellulite Dessert – Blueberry Aspic and Gotu Kola
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Instead, a consideration must be made on the suitability for philosophical or religious nutritional regimes. All animal jellies are to be avoided in vegetarian diets, in Hinduism and Buddhism. Those from kosher and halal fish are relevant in Judaism and Muslimism; the sturgeon but is considered an unclean animal, and therefore should be avoided. They abhor the pig but not the bovine, if slaughtered according to certain criteria.
Uses
Isinglass in cooking
Before collagen was obtained from the cartilage and skin of terrestrial animals, thickeners and gelling agents were made from isinglass. This was commonly used in sweet confectionery in many recipes, for example fruit jellies, white puddings – such as blancmange – etc.
To be sure, food jellies all serve the same purpose. However, many know that “thickening” and “gelifying” are not exactly the same thing. For example, a custard must be “creamy”, not simply “thick” and even less “gelatinous”. On the contrary, a fruit jam should have a thick consistency, therefore dense, not creamy or gelatinous. And again, speaking of a pudding, it is essential that it has the structure and the trembling of a jelly, it must not flake or even stick to the mold.
Isinglass, or rather all animal collagens, above all have a gelatinizing capacity; another example is agar agar. Pectins, on the other hand, are more suitable for thickening, especially aqueous mixtures rich in sugars . To increase the creaminess, however, emulsions of fats and water rich in lecithins are particularly suitable .
Animal collagens are not suitable, for example, for jams and not even for 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 might be the natural texture of isinglass is sufficient to observe the broth of meat refrigerated; if well concentrated and kept at 4-5 ° C, it assumes a typically “flickering” consistency, to liquefy as soon as it is heated. In this case, the collagen comes from the connective tissues of the meat which tend to melt when boiled.
Isinglass is also still used to optimize the preservation of certain canned products, both for human nutrition – see jellied meat – and for animal nutrition, such as wet cat food; below we offer you a homemade recipe for your four-legged friend.
Wet Cat Food – Homemade Meat in Jelly
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Isinglass to clarify and refine drinks
Isinglass-based finings are widely used in the UK as precipitation and clarification accelerators in the brewing industry. In essence, it is a chemical process that replaces physical microfiltration and as such does not require heat treatments or membranous passages.
Isinglass-based 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 “raw” beer, these flocculate the live yeasts forming a gelatinous mass which tends to precipitate. By avoiding stirring the liquid or otherwise moving the deposit on the bottom, this allows the beer to clear naturally and faster than normal.
Did you know that …
Flocculation is a chemical-physical mechanism that affects colloidal systems, in which the solid phase tends to separate, forming suspended flakes.
Non-cask beers, on the other hand, are generally pasteurized , which allows rapid precipitation with deposit, which can be easily removed by physical filtration. Obviously, the heat treatment alters the organoleptic and taste 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 for recovering the most impure batches.
Although only traces of isinglass can be identified in finished beer, many vegetarians consider these drinks – still widespread today, especially in the UK – unsuitable for their diet. Therefore a vegetable alternative was proposed, in an attempt to reproduce the same clarifying power; this is the case of carrageenan extracted from crondo crispo or carragheen (genus Chondrus and species crispus ), a type of red alga . This polysaccharide is used both during the thermal process and after fermentation, but above all it reduces the concentration of the suspended protein mass and not that of the microorganisms. Conversely, isinglass is mostly used to remove yeast. Since the two clarifying agents act differently, to the detriment of vegetarians, they are not actually interchangeable and many beers use both.
Isinglass finings are also used in the production of kosher wines – or permitted by the Jewish religion – even if for reasons of kashrut they cannot derive from beluga sturgeon, considered impure and therefore not kosher.
Isinglass 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, in which fresh eggs were immersed .
Isinglass as a preservative for parchments
Isinglass is used for the restoration of scrolls. After soaking in water and cooking at 45 ° C, with the addition of decanted tragacanth ( emulsifier ), a very useful compound is obtained to repair the flaking paint of these manuscripts – previously softened with ethanol . This can be applied directly to the spot, 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 cover 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 especially advantageous in situations where you want to use very little water. It also has higher adhesive strength than many other products used for scroll repair.
History
History of isinglass
Although originally it was produced exclusively starting from the “beluga” sturgeon (Genus Huso and species huso ), typical of the seas and rivers located in north-east Euro-Asia, in 1795 William Murdoch introduced the use of cod , more available and to cheap. From then on, especially in Great Britain, cod isinglass replaced the imported Russian one.
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 the German language, “hausen blas” has essentially the same meaning.
