Gelatin is an animal protein which, in addition to being a nutrient by providing protein in the diet, has an important technological role in the formulation of foods such as dairy and non-dairy desserts, meat products, ready meals and confectionery.
Gelatin is a protein obtained by solubilising collagen from the connective tissue of various animals, such as pigs, cattle, poultry and fish. Connective tissue is the supporting tissue of the organism and is mainly found in the skin and joints.
The collagen forming connective tissue is a triple helix protein structure, very resistant and not at all soluble. Meat rich in collagen is difficult to eat unless it is stewed, a process which, thanks to prolonged cooking, transforms the collagen into gelatin. Similarly, skins and bones undergo heat treatment in an acid or alkaline medium and a subsequent filtration and purification process to obtain gelatin as we know it.
When obtained in an acid medium it is called “Gelatin A” and has an isoelectric point around pH 8, while that obtained in an alkaline medium is called “Gelatin B” and its isoelectric point is around pH 5.
Although gelatin sheets are used in traditional cooking, in industry it is used in powder or granulated form (size measured in Mesh), of different gelation strength (measured in Bloom degrees) and of different origin (mainly pork and beef). Poultry gelatin is rarely used and fish gelatin is mainly used in pharmaceuticals.
A few years ago, its main use was in photography, as it was used to form very thin and transparent films that fixed the silver salts on negatives and papers. Nowadays, due to the rise of digital photography, this application is no longer used.
Use in nutrition
Some of its typical uses are:
- Fruit-flavoured jelly desserts
- Gummy candies and marshmallows
- Dairy desserts or milk alternatives
- Mousses and foams
- Instant desserts for home use
- Coatings of pâtés
- Coating of cooked hams in bags
Gelatin is a protein composed mainly of glycine (25-27%), proline (13-15%) and hydroxyproline (10-12%). It is a protein of low biological value as its essential amino acid content is low, and even void in the case of tryptophan. Even so, it is an important source of protein, especially if it is combined with others providing the essential amino acids it lacks.
Gelatin is insoluble in cold water. It simply hydrates and swells in it. This prior hydration process is important for proper solubilisation. Coarser particle gelatines (low Mesh) hydrate more slowly but do not form as many lumps as finer gelatines (high Mesh). These more powdery gelatins are often used pre-mixed with other powdered products such as sugars, starches, flavourings, etc.
Once hydrated, the gelatin is solubilised by heating the solution. High temperatures are not necessary. Once dissolved, the gelatin solution is transparent and does not add viscosity to the liquid, usually water or milk.
When the dissolution cools, it gels to form a soft, highly elastic, syneresis-free gel that is thermo-reversible. In fact, most gelatin solutions melt and return to a liquid state at mouth temperature, which makes them very interesting ingredients for their creaminess and palatability. The melting temperature increases with increasing concentration. For this reason, gummies no longer melt and must be chewed.
Another technological characteristic of gelatin is its ability to form and stabilise foams, so it is typically found in aerated desserts such as mousses or whipped creams.
Gelatin for cold use: desserts and more applications
A special case is “instant” or cold-soluble gelatin. This is gelatin dried by a special process that makes it soluble without heating. This type of gelatin is mainly used in the preparation of desserts without heating, only by mixing the ingredients in milk or another liquid and leaving it to stand for a while in the refrigerator. This characteristic saves time and energy costs and also opens up the possibility for children to participate in culinary preparations without the risk of burns.
To solve the problem of lumps forming during cold application, we also offer an easy-to-disperse reference that is 100% pure gelatin, where the granule itself dissolves in cold in an efficient way, without the need to add any other ingredient. This results in a natural product, without additives and in all its varieties, suitable for clean label and allergen-free preparations.
Quimidroga offers different types of gelatin: classic, instant and easy-to-disperse instant.