Gelatin or gelatine (from Latin gelatus 'stiff, frozen') is a translucent, colorless, flavorless food ingredient, commonly derived from collagen taken from animal body parts. It is brittle when dry and rubbery when moist. It may also be referred to as hydrolyzed collagen, collagen hydrolysate, gelatine hydrolysate, hydrolyzed gelatine, and collagen peptides after it has undergone hydrolysis. It is commonly used as a gelling agent in food, beverages, medications, drug or vitamin capsules, photographic films, papers, and cosmetics.
Substances containing gelatin or functioning in a similar way are called gelatinous substances. Gelatin is an irreversibly hydrolyzed form of collagen, wherein the hydrolysis reduces protein fibrils into smaller peptides; depending on the physical and chemical methods of denaturation, the molecular weight of the peptides falls within a broad range. Gelatin is present in gelatin desserts, most gummy candy and marshmallows, ice creams, dips, and yogurts. [1] Gelatin for cooking comes as powder, granules, and sheets. Instant types can be added to the food as they are; others must soak in water beforehand.
Gelatin is a collection of peptides and proteins produced by partial hydrolysis of collagen extracted from the skin, bones, and connective tissues of animals such as domesticated cattle, chicken, pigs, and fish. During hydrolysis, some of the bonds between and within component proteins are broken. Its chemical composition is, in many aspects, closely similar to that of its parent collagen. [2] Photographic and pharmaceutical grades of gelatin generally are sourced from cattle bones and pig skin. Gelatin is classified as a hydrogel.
Gelatin is nearly tasteless and odorless with a colorless or slightly yellow appearance. [3] [4] It is transparent and brittle, and it can come as sheets, flakes, or as a powder. [3] Polar solvents like hot water, glycerol, and acetic acid can dissolve gelatin, but it is insoluble in organic solvents like alcohol. [3] Gelatin absorbs 5–10 times its weight in water to form a gel. [3] The gel formed by gelatin can be melted by reheating, and it has an increasing viscosity under stress (thixotropic). [3] The upper melting point of gelatin is below human body temperature, a factor that is important for mouthfeel of foods produced with gelatin. [5] The viscosity of the gelatin-water mixture is greatest when the gelatin concentration is high and the mixture is kept cool at about 4 °C (39 °F). Commercial gelatin will have a gel strength of around 90 to 300 grams Bloom using the Bloom test of gel strength. [6] Gelatin's strength (but not viscosity) declines if it is subjected to temperatures above 100 °C (212 °F), or if it is held at temperatures near 100 °C for an extended period of time. [7] [8]
Gelatins have diverse melting points and gelation temperatures, depending on the source. For example, gelatin derived from fish has a lower melting and gelation point than gelatin derived from beef or pork. [9]
When dry, gelatin consists of 98–99% protein, but it is not a nutritionally complete protein since it is missing tryptophan and is deficient in isoleucine, threonine, and methionine. [10] The amino acid content of hydrolyzed collagen is the same as collagen. Hydrolyzed collagen contains 19 amino acids, predominantly glycine (Gly) 26–34%, proline (Pro) 10–18%, and hydroxyproline (Hyp) 7–15%, which together represent around 50% of the total amino acid content. [11] Glycine is responsible for close packing of the chains. Presence of proline restricts the conformation. This is important for gelation properties of gelatin. [12] Other amino acids that contribute highly include: alanine (Ala) 8–11%; arginine (Arg) 8–9%; aspartic acid (Asp) 6–7%; and glutamic acid (Glu) 10–12%. [11]
In 2011, the European Food Safety Authority Panel on Dietetic Products, Nutrition and Allergies concluded that "a cause and effect relationship has not been established between the consumption of collagen hydrolysate and maintenance of joints". [13]
Hydrolyzed collagen, like gelatin, is made from animal by-products from the meat industry or sometimes animal carcasses removed and cleared by knackers, including skin, bones, and connective tissue.
In 1997, the U.S. Food and Drug Administration (FDA), with support from the TSE (transmissible spongiform encephalopathy) Advisory Committee, began monitoring the potential risk of transmitting animal diseases, especially bovine spongiform encephalopathy (BSE), commonly known as mad cow disease. [14] An FDA study from that year stated: "... steps such as heat, alkaline treatment, and filtration could be effective in reducing the level of contaminating TSE agents; however, scientific evidence is insufficient at this time to demonstrate that these treatments would effectively remove the BSE infectious agent if present in the source material." [15] On 18 March 2016, the FDA finalized three previously issued interim final rules designed to further reduce the potential risk of BSE in human food. [16] The final rule clarified that "gelatin is not considered a prohibited cattle material if it is manufactured using the customary industry processes specified." [17]
The Scientific Steering Committee (SSC) of the European Union in 2003 stated that the risk associated with bovine bone gelatin is very low or zero. [18] [19]
In 2006, the European Food Safety Authority stated that the SSC opinion was confirmed, that the BSE risk of bone-derived gelatin was small, and that it recommended removal of the 2003 request to exclude the skull, brain, and vertebrae of bovine origin older than 12 months from the material used in gelatin manufacturing. [20]
In 2019, the worldwide demand of gelatin was about 620,000 tonnes (1.4×10 9 lb). [21] On a commercial scale, gelatin is made from by-products of the meat and leather industries. Most gelatin is derived from pork skins, pork and cattle bones, or split cattle hides. [22] Gelatin made from fish by-products avoids some of the religious objections to gelatin consumption. [5] The raw materials are prepared by different curing, acid, and alkali processes that are employed to extract the dried collagen hydrolysate. These processes may take several weeks, and differences in such processes have great effects on the properties of the final gelatin products.
Gelatin also can be prepared at home. Boiling certain cartilaginous cuts of meat or bones results in gelatin being dissolved into the water. Depending on the concentration, the resulting stock (when cooled) will form a jelly or gel naturally. This process is used for aspic.
While many processes exist whereby collagen may be converted to gelatin, they all have several factors in common. The intermolecular and intramolecular bonds that stabilize insoluble collagen must be broken, and also, the hydrogen bonds that stabilize the collagen helix must be broken. [2] The manufacturing processes of gelatin consists of several main stages:
If the raw material used in the production of the gelatin is derived from bones, dilute acid solutions are used to remove calcium and other salts. Hot water or several solvents may be used to reduce the fat content, which should not exceed 1% before the main extraction step. If the raw material consists of hides and skin; size reduction, washing, removal of hair from hides, and degreasing are necessary to prepare the hides and skins for the hydrolysis step.
After preparation of the raw material, i.e., removing some of the impurities such as fat and salts, partially purified collagen is converted into gelatin through hydrolysis. Collagen hydrolysis is performed by one of three different methods: acid-, alkali-, and enzymatic hydrolysis. Acid treatment is especially suitable for less fully cross-linked materials such as pig skin collagen and normally requires 10 to 48 hours. Alkali treatment is suitable for more complex collagen such as that found in bovine hides and requires more time, normally several weeks. The purpose of the alkali treatment is to destroy certain chemical crosslinks still present in collagen. Within the gelatin industry, the gelatin obtained from acid-treated raw material has been called type-A gelatin and the gelatin obtained from alkali-treated raw material is referred to as type-B gelatin. [23]
Advances are occurring to optimize the yield of gelatin using enzymatic hydrolysis of collagen. The treatment time is shorter than that required for alkali treatment, and results in almost complete conversion to the pure product. The physical properties of the final gelatin product are considered better. [24]
Extraction is performed with either water or acid solutions at appropriate temperatures. All industrial processes are based on neutral or acid pH values because although alkali treatments speed up conversion, they also promote degradation processes. Acidic extraction conditions are extensively used in the industry, but the degree of acid varies with different processes. This extraction step is a multistage process, and the extraction temperature usually is increased in later extraction steps, which ensures minimum thermal degradation of the extracted gelatin.
This process includes several steps such as filtration, evaporation, drying, grinding, and sifting. These operations are concentration-dependent and also dependent on the particular gelatin used. Gelatin degradation should be avoided and minimized, so the lowest temperature possible is used for the recovery process. Most recoveries are rapid, with all of the processes being done in several stages to avoid extensive deterioration of the peptide structure. A deteriorated peptide structure would result in a low gel strength, which is not generally desired.
The 10th-century Kitab al-Tabikh includes a recipe for a fish aspic, made by boiling fish heads. [25]
A recipe for jelled meat broth is found in Le Viandier , written in or around 1375. [26]
In 15th century Britain, cattle hooves were boiled to produce a gel. [27] By the late 17th century, the French inventor Denis Papin had discovered another method of gelatin extraction via boiling of bones. [28] An English patent for gelatin production was granted in 1754. [27] In 1812, the chemist Jean-Pierre-Joseph d'Arcet further experimented with the use of hydrochloric acid to extract gelatin from bones, and later with steam extraction, which was much more efficient. The French government viewed gelatin as a potential source of cheap, accessible protein for the poor, particularly in Paris. [29]
Food applications in France and the United States during the 19th century appear to have established the versatility of gelatin, including the origin of its popularity in the US as Jell-O. [30] In the mid-19th century, the American industrialist and inventor, Peter Cooper, registered a patent for a gelatin dessert powder he called "Portable Gelatin", which only needed the addition of water. In the late 19th century, Charles and Rose Knox set up the Charles B. Knox Gelatin Company in New York, which promoted and popularized the use of gelatin. [31]
Probably best known as a gelling agent in cooking, different types and grades of gelatin are used in a wide range of food and nonfood products. Common examples of foods that contain gelatin are gelatin desserts, trifles, aspic, marshmallows, candy corn, and confections such as Peeps, gummy bears, fruit snacks, and jelly babies. [32] Gelatin may be used as a stabilizer, thickener, or texturizer in foods such as yogurt, cream cheese, and margarine; it is used, as well, in fat-reduced foods to simulate the mouthfeel of fat and to create volume. It also is used in the production of several types of Chinese soup dumplings, specifically Shanghainese soup dumplings, or xiaolongbao , as well as Shengjian mantou , a type of fried and steamed dumpling. The fillings of both are made by combining ground pork with gelatin cubes, and in the process of cooking, the gelatin melts, creating a soupy interior with a characteristic gelatinous stickiness.
Gelatin is used for the clarification of juices, such as apple juice, and of vinegar. [33]
Isinglass is obtained from the swim bladders of fish. It is used as a fining agent for wine and beer. [34] Besides hartshorn jelly, from deer antlers (hence the name "hartshorn"), isinglass was one of the oldest sources of gelatin.
In cosmetics, hydrolyzed collagen may be found in topical creams, acting as a product texture conditioner, and moisturizer. Collagen implants or dermal fillers are also used to address the appearance of wrinkles, contour deficiencies, and acne scars, among others. The U.S. Food and Drug Administration has approved its use, and identifies cow (bovine) and human cells as the sources of these fillers. According to the FDA, the desired effects can last for 3–4 months, which is relatively the most short-lived compared to other materials used for the same purpose. [35]
This section needs additional citations for verification .(September 2016) |
The consumption of gelatin from particular animals may be forbidden by religious rules or cultural taboos.
Islamic halal and Jewish kosher customs generally require gelatin from sources other than pigs, such as cattle that have been slaughtered according to religious regulations (halal or kosher), or fish (that Jews and Muslims are allowed to consume). [43]
On the other hand, some Islamic jurists have argued that the chemical treatment "purifies" the gelatin enough to always be halal, an argument most common in the field of medicine. [43]
It has similarly been argued that gelatin in medicine is permissible in Judaism, as it is not used as food. [44] According to The Jewish Dietary Laws, the book of kosher guidelines published by the Rabbinical Assembly, the organization of Conservative Jewish rabbis, all gelatin is kosher and pareve because the chemical transformation undergone in the manufacturing process renders it a different physical and chemical substance. [45]
Sikh, Hindu, and Jain customs may require gelatin alternatives from sources other than animals, as many Hindus, almost all Jains and some Sikhs are vegetarian. [46]
Aspartame is an artificial non-saccharide sweetener 200 times sweeter than sucrose and is commonly used as a sugar substitute in foods and beverages. It is a methyl ester of the aspartic acid/phenylalanine dipeptide with brand names NutraSweet, Equal, and Canderel. Aspartame was approved by the US Food and Drug Administration (FDA) in 1974, and then again in 1981, after approval was revoked in 1980.
Biopolymers are natural polymers produced by the cells of living organisms. Like other polymers, biopolymers consist of monomeric units that are covalently bonded in chains to form larger molecules. There are three main classes of biopolymers, classified according to the monomers used and the structure of the biopolymer formed: polynucleotides, polypeptides, and polysaccharides. The Polynucleotides, RNA and DNA, are long polymers of nucleotides. Polypeptides include proteins and shorter polymers of amino acids; some major examples include collagen, actin, and fibrin. Polysaccharides are linear or branched chains of sugar carbohydrates; examples include starch, cellulose, and alginate. Other examples of biopolymers include natural rubbers, suberin and lignin, cutin and cutan, melanin, and polyhydroxyalkanoates (PHAs).
Gelatin desserts are desserts made with a sweetened and flavoured processed collagen product (gelatin). This kind of dessert was first recorded as jelly by Hannah Glasse in her 18th-century book The Art of Cookery, appearing in a layer of trifle. Jelly is also featured in the best selling cookbooks of English food writers Eliza Acton and Isabella Beeton in the 19th century.
Carrageenans or carrageenins are a family of natural linear sulfated polysaccharides that are extracted from red edible seaweeds. Carrageenans are widely used in the food industry, for their gelling, thickening, and stabilizing properties. Their main application is in dairy and meat products, due to their strong binding to food proteins. In recent years, carrageenans have emerged as a promising candidate in tissue engineering and regenerative medicine applications as they resemble native glycosaminoglycans (GAGs). They have been mainly used for tissue engineering, wound coverage, and drug delivery.
Gummy bears are small, fruit gum candies, similar to a jelly baby in some English-speaking countries. The candy is roughly 2 cm (0.8 in) long and shaped in the form of a bear. The gummy bear is one of many gummies, popular gelatin-based candies sold in a variety of shapes and colors.
Mechanically separated meat (MSM), mechanically recovered/reclaimed meat (MRM), or mechanically deboned meat (MDM) is a paste-like meat product produced by forcing pureed or ground beef, pork, mutton, turkey or chicken under high pressure through a sieve or similar device to separate the bone from the edible meat tissue. When poultry is used, it is sometimes called white slime as an analog to meat-additive pink slime and to meat extracted by advanced meat recovery systems, both of which are different processes. The process entails pureeing or grinding the carcass left after the manual removal of meat from the bones and then forcing the slurry through a sieve under pressure.
Calorad Classic is a liquid protein weight loss supplement which was first introduced to the US and Canadian marketplace in 1984. It has been advertised on both television and radio. Calorad Classic is manufactured by NutriDiem and is marketed by several companies including Essentially Yours Industries and Nysante, all of which are headquartered in Canada.
Whey protein is a mixture of proteins isolated from whey, the liquid material created as a by-product of cheese production. The proteins consist of α-lactalbumin, β-lactoglobulin, serum albumin and immunoglobulins. Glycomacropeptide also makes up the third largest component but is not a protein. Whey protein is commonly marketed as a protein supplement, and various health claims have been attributed to it. A review published in 2010 in the European Food Safety Authority Journal concluded that the provided literature did not adequately support the proposed claims.
Hydrolyzed protein is a solution derived from the hydrolysis of a protein into its component amino acids and peptides. While many means of achieving this exist, most common is prolonged heating with hydrochloric acid, sometimes with an enzyme such as pancreatic protease to simulate the naturally occurring hydrolytic process.
Hydrolyzed vegetable protein (HVP) products are foodstuffs obtained by protein hydrolysis and are used as ingredients to create a bouillon (broth) taste without the vegetables, bones, simmering, or other standard elements of creating bouillon from scratch.
A thickening agent or thickener is a substance which can increase the viscosity of a liquid without substantially changing its other properties. Edible thickeners are commonly used to thicken sauces, soups, and puddings without altering their taste; thickeners are also used in paints, inks, explosives, and cosmetics.
Caramel color or caramel coloring is a water-soluble food coloring. It is made by heat treatment of carbohydrates (sugars), in general in the presence of acids, alkalis, or salts, in a process called caramelization. It is more fully oxidized than caramel candy, and has an odor of burnt sugar and a somewhat bitter taste. Its color ranges from pale yellow to amber to dark brown.
John Mark Purdey was an English organic farmer who came to public attention in the 1980s, when he began to circulate his own theories regarding the causes of bovine spongiform encephalopathy.
Bovine spongiform encephalopathy (BSE), commonly known as mad cow disease, is an incurable and invariably fatal neurodegenerative disease of cattle. Symptoms include abnormal behavior, trouble walking, and weight loss. Later in the course of the disease, the cow becomes unable to function normally. There is conflicting information about the time between infection and onset of symptoms. In 2002, the World Health Organization (WHO) suggested it to be approximately four to five years. Time from onset of symptoms to death is generally weeks to months. Spread to humans is believed to result in variant Creutzfeldt–Jakob disease (vCJD). As of 2018, a total of 231 cases of vCJD had been reported globally.
Meat and bone meal (MBM) is a product of the rendering industry. It is typically about 48–52% protein, 33–35% ash, 8–12% fat, and 4–7% water. It is primarily used in the formulation of animal feed to improve the amino acid profile of the feed. Feeding of MBM to cattle is thought to have been responsible for the spread of BSE ; therefore, in most parts of the world, MBM is no longer allowed in feed for ruminant animals. However, it is still used to feed monogastric animals.
The term Feed ban is usually a reference to the regulations that have prohibited the feeding of most mammalian-derived proteins to cattle as a method of preventing the spread of bovine spongiform encephalopathy (BSE). Feeding of infected ruminant material back to ruminants is believed to be the most likely means of transmission of the disease.
Meat on the bone or bone-in meat is meat that is sold with some or all of the bones included in the cut or portion, i.e. meat that has not been filleted. The phrase "on the bone" can also be applied to specific types of meat, most commonly ham on the bone, and to fish. Meat or fish on the bone may be cooked and served with the bones still included or the bones may be removed at some stage in the preparation.
Ossein is the organic extracellular matrix of bone, which is made of 95% collagen. This substance is used in industry for the production of gelatin and bone glue.
The United Kingdom was afflicted with an outbreak of Bovine spongiform encephalopathy, and its human equivalent variant Creutzfeldt–Jakob disease (vCJD), in the 1980s and 1990s. Over four million head of cattle were slaughtered in an effort to contain the outbreak, and 178 people died after contracting vCJD through eating infected beef. A political and public health crisis resulted, and British beef was banned from export to numerous countries around the world, with some bans remaining in place until as late as 2019.
The Beef Bones Regulations 1997 was a statutory instrument of the British government that limited the sale of beef on the bone. The regulations were implemented as a response to the United Kingdom BSE outbreak over fears that variant Creutzfeldt–Jakob disease in humans might be caused by the consumption of dorsal root ganglia, which lie near the bone. As well as beef on the bone, all beef-bone derived products were prohibited from sale. This had the effect of outlawing T-bone steaks, prime ribs and oxtail as well as some soups and stocks. Other aspects of the regulations dealt with the deboning of beef and the keeping of records in the food production industry. The restrictions on sales were lifted in December 1999 and the regulations as a whole were revoked in April 2008.
Finally, the rule provides a definition of gelatin and clarifies that gelatin is not considered a prohibited cattle material if it is manufactured using the customary industry processes specified. Gelatin was never considered a prohibited cattle material, but FDA had never specifically defined gelatin in past IFRs.
Media related to Gelatin at Wikimedia Commons