Gelatin information, news, history and more

Commercial gelatins vary from 50 to 300 Bloom grams and, except for specialty items, are free of added colors, flavors, preservatives, and chemical additives. Gelatin is a generally recognized as safe (GRAS) food ingredient.

Two of gelatin's most desirable properties are its melt-in-the-mouth characteristics and its ability to form thermoreversible gels. In addition, gelatin is relatively unaffected by ionic strength and is stable over a broad pH range. Gelatin is preferred in many applications for its clarity and bland flavor.

Table 2 lists several food categories which utilize gelatin, and recommended use levels and Blooms.

Confectionery - Confections are typically made from a base of sugar, corn syrup and water. To this base is added flavor, color and texture modifiers. Gelatin is widely used in confections because it foams, gels, or solidifies into a piece that dissolves slowly or melts in the mouth.

Confections such as gummi bears contain a relatively high percentage of gelatin. These candies dissolve more slowly thus lengthening the enjoyment of the candy while smoothing the flavor.

Gelatin is used in whipped confections such as marshmallows where it serves to lower the surface tension of the syrup, stabilize the foam through increased viscosity, set the foam via gelation, and prevent sugar crystallization.

Gelatin is used in foamed confections at a 2-7% level, depending upon the desired texture. Gummi foams use about 7% of a 200 - 275 Bloom gelatin. Marshmallow producers generally use 2.5% of a 250 Bloom Type A gelatin.

Gelatin Desserts - Gelatin desserts can be traced back to 1845 when a U.S. patent was issued use for "portable gelatin" for use in desserts. Gelatin desserts remain popular: the current U.S. market for gelatin desserts exceeds 100 million pounds annually.

Today’s consumers are concerned with caloric intake. Regular gelatin desserts are easy to prepare, pleasant tasting, nutritious, available in a variety of flavors, and contain only 80 calories per half-cup serving. Sugar-free versions are a mere eight calories per serving.

The buffer salts are used to maintain the proper pH for flavor and setting characteristics. Historically, a small amount of salt was added as a flavor enhancer.

Gelatin desserts can be prepared using either Type A or Type B gelatin with Blooms between 175 and 275. The higher the Bloom the less gelatin required for a proper set (i.e. 275 Bloom gelatin will require about 1.3% gelatin while a 175 Bloom gelatin will require 2.0% to obtain an equal set). Sweeteners other than sucrose can be used.

Gelatin in Meats – Gelatin is used to gel aspics, head cheese, souse, chicken rolls, glazed and canned hams, and jellied meat products of all kinds. The gelatin functions to absorb meat juices and to give form and structure to products that would otherwise fall apart. Normal usage level ranges from 1 to 5% depending upon the type of meat, amount of broth, gelatin Bloom, and texture desired in the final product.

Clarification of Beverages and Juices – Gelatin has traditionally been used to clarify wine, beer and fruit juices. Fining of these beverages requires only 40 to 80 parts per million of a 100 to 200 Bloom gelatin. In practice a dilute (1-3%) gelatin solution is introduced into the top of the tank and then allowed to settle before filtration.

Special Dietary Uses – Gelatin in hydrolyzed form is used to protein fortify dietary foods. Dried, hydrolyzed gelatin contains over 92% protein. Typically it is blended with other hydrolyzed proteins to balance the nutritional aspects of the amino acids. Soups, shakes, and fruit drinks are common uses for gelatin hydrolysates.

Dietary concerns with collagen protein have been misunderstood for many years. While collagen has been described as an empty protein, or one having little nutritional value, it does in fact contain many essential amino acids, and is readily digested.

C. E. Bodwell reported that collagen can replace 30-40% of the protein in meat and still deliver a protein efficiency ratio greater than 2.0. He went on to state that in practice, the addition of collagen to meat products at levels of 25-30% would not be expected to have a significant effect on the protein nutritional status of individuals consuming meat products. In the U.S., an excess of protein is routinely consumed and marginal levels of tryptophan are probably not of serious concern, stated Dr. Bodwell.

The digestibility of collagen is very high. Laser-Reutersward et al. Demonstrated that in rats, over 90% of collagen was truly digestible, regardless of whether the collagen was heat treated or not.

Rogowski graphically showed that mixtures of beef muscle and gelatin actually increased the biological value by 7% when gelatin was added as 16% of the mixture. A 50/50 blend of gelatin/beef muscle had the same biological value as beef muscle alone. The point is that although humans should consume combinations of proteins from various sources for optimum utilization of the amino acids, collagen (gelatin) can comprise from 25 to 50 % of the protein and still meet or exceed adult nutritional needs.

Gelatin is not a complete protein for mammalian nutrition. It lacks the essential amino acid tryptophan and is deficient in sulfur-containing amino acids. Amino acid analysis of gelatins derived from common collagen sources is given in Table 1.

Gelatin is compatible with a wide variety of foods and ingredients. In fact, it has been used to help keep together ingredients that are incompatible. Some general nutritional information on gelatin is presented in Table 3.

These figures are typical values or ranges which will vary greatly depending upon the type of raw material and methods of manufacture. They should not be used for label claims.

Gelatin is truly remarkable in terms of its many functional properties in food applications. A variety of examples are given in Table 4.

Pharmaceutical Gelatins

The use of gelatin in the manufacture of various pharmaceutical dosage forms dates back to the early 19th century and possibly earlier. Today, the commonly recognized dosage forms using gelatin are two-piece hard capsules, soft elastic capsules (Softgels), tableting, tablet coating, granulation, encapsulation and micro-encapsulation. All gelatins used meet or exceed the requirements of the current United States Pharmacopoeia and National Formulary. The use of gelatin in the various dosage forms consumes several million pounds annually.

Two-Piece Hard Capsules – The manufacture of hard gelatin capsules consists of the dipping of stainless steel mold pins into a gelatin solution, drying, stripping from the pins into a collate, trimming of the caps and bodies, and joining together for shipment. The strength and flexibility, the clarity of the gelatin, and
the movability of the gelatin provide unique characteristics that allow the manufacture of various sizes, colors and designs for assuring a snap closure after filling.

Both types of gelatin are used, either in combination or separately, according to the final active fill product. Many hard capsules are produced today with a variety of tamper-evident closure systems that lock the cap to the capsule body and prevent easy opening. In addition, several sealing systems have been developed that place a colored gelatin band around the capsule, spot weld the capsule, gluing the capsule and heat sealing the filled capsule.

Soft Elastic Gelatin Capsules – Softgels, as they are commonly known today, utilize a gelatin solution that is plasticized with propylene glycol, sorbitol, glycerin or various approved mixtures. Soft gelatin capsules are one-piece and hermetically sealed to enclose a liquid or semi-liquid fill. Soft gelatin capsules are manufacture-formed, filled and sealed in one continuous operation.

The soft gelatin encapsulation process begins with the formation of two sheets called ribbons from a molten gelatin mass, each of which is passed over a die of the desired capsule size and shape. At the point where the two rotating dies meet, the capsule is formed and filled with a liquid that contains the active ingredient in a vehicle. The capsule is then washed to remove the lubricants and dried.

In 1932, R. P. Scherer developed the first rotary die encapsulation system: since that time the technology has been refined into a completely automatic process. The rotary die method has the advantage of producing a capsule with highly accurate dosage levels, can prevent photochemical deterioration of the active ingredient and masks unpleasant tastes.

Tablets – Tablets are defined as solid pharmaceutical dosage forms containing drug substances, with or without diluents, and prepared by compression or molding methods. Tablets are generally prepared by the compression method for most applications. The tablet formulation consists of an active or therapeutic ingredient and several inert materials known as excipients, which are classified as to the role in the tablet process. All tablets contain diluents, binders, glidants and lubricants. Gelatin is used in the preparation of the active (granulation) and as a binder in the tablet. The tableting process consists of several phases of preparation which are necessary to produce the finished tablet.

The first step is typically the granulation of the active ingredient to a particle size close to that of the other ingredients. This is performed by various size enhancement techniques including granulation, extrusion and compression. In all three techniques gelatin is used for its adhesive properties. The natural tack of the gelatin assists in the agglomeration of the particles.

The second step is a granulation technique with all the excipients added. The granulation is controlled to produce a homogeneous and properly sized granulate. Gelatin solutions are used as the binder in this process to form larger agglomerates containing the active, binder, diluents and glidants. The use of gelatin in the granulation process provides an efficient means for reducing fines and maintaining physiological inertness.

Tablet granulates are then compressed into the proper shape, density and size by use of a tablet press. The compression exerted by the tablet press on the powder granulate is such that the agglomerates shatter and upon further compression lock together. The advantage of gelatin is that not only is the shattering of the agglomerates accomplished, but the adhesive properties of the gelatin act as an additional adhesive.

Tablet Coating – Tablets are generally coated to reduce dusting, mask unpleasant taste, and allow for printing and color coatings for product identification. The coating process is more and more becoming aqueous-based which allows for the use of gelatin. Typical formulations for coating include a sugar, pigment, and gelatin to act as a film former. The most popular coating method utilizes a roll coating pan and the addition of the coating solution as a fine spray.

Suppositories – Glycerinated gelatin is typically used as a vehicle for suppositories for insertion into the rectum, vagina or the urethra. The firmness of the finished product is adjusted by varying the gelatin concentration in the formula. The criteria for any suppository formulation are that the base (gelatin) be nontoxic and nonirritating to mucous membranes, compatible with a variety of drugs, the base melts or dissolves in body fluids, and the base should be stable on storage. Suppositories are generally molded by compression or by fusion molding. The gelatin base affords all the desired characteristics required by either method. The two types of gelatin each provide characteristics that are advantageous for formulation dependent upon the active and the area of application.

Type A gelatin is generally adjusted to an acidic pH which is below the isoelectric point, while a Type B gelatin is also adjusted to a pH that is acidic, but in this case the pH is above the isoelectric point. Thus the cationic, anionic, and the nonionic characteristics can be used to promote compatibility with the active, compatibility with the surrounding fluids and temperatures, and enhance or control the bioavailability.

The pH exists where the positive and negative charges are equivalent and the application of an electric charge has no effect. The principal chemical and physical characteristics of a gelatin solution are dependent upon the pH and the ionic strength of the media. The formulation and preparation of the gelatin can in fact modify the isoelectric point in such a way that various physical characteristics can be enhanced. The suppository dosage form is just one example of the use of varied isoelectric points that enhance the performance of the drug delivery system.

Gelatin Emulsions – Gelatin is recognized in many industries as a stabilizer, a texturizing agent, a film former and as a colloidal support media. The preparation of an oil emulsion with gelatin for use as a topical allows the oils to be stored and maintains droplet distribution and droplet size over extended periods. Depending upon the concentration and temperature, the emulsion can be free flowing, semi-solid or solid. These properties are further enhanced with the addition of gums that can provide the additional viscosity for the application, yet retain the colloidal support for the dispersed oil.

Microencapsulation – Gelatin is used to produce microencapsulated oils for various uses both in nutritional and pharmaceutical applications. The traditional method of encapsulation is known as coacervation in which the dispersed oil is encapsulated by gelatin at the interface between the aqueous phase and the non-aqueous phases. Common examples of this are vitamin supplements for various foods and for multi-vitamins. The size and formation of the spherical microcapsules can be controlled by various methods. Typical microcapsules range in size from 5 microns to 500 microns.

Absorbable Gelatin Sponge – Gelatin is used in the form of a sterile, water insoluble sponge (Gelfoam ^TM) to control bleeding during surgery. It is later absorbed over a 4 to 6 week period.

Absorbable Gelatin Film – Another application is a sterile, non-antigenic, water-insoluble, absorbable gelatin film (Gelfilm ^TM) obtained from a specially prepared gelatin/formaldehyde solution.

Pastilles and Troches – These products are commonly used as cough drops. Like gelled confections, these products are unique in that in the mouth they are surrounded by a fluid that prevents the active ingredient from being concentrated and creating irritations.

Bacterial Growth Media – As with any pharmaceutical excipient, the level and type of bacteria found is always of concern. Pharmaceutical gelatin is highly purified and sterilized to eliminate these concerns. However, as gelatin is derived from collagen, the ability to perform as a nutrient is itself an application. Special grades of gelatin are useful in bacterial culture media. The specificity of the media to detect and count various bacterial strains is a useful diagnostic and research tool. A variety of media are available that utilize the nutrient properties of gelatin.

Photographic Gelatins

The use of gelatin in photographic emulsions dates back to about 1870 when Dr. Maddox of England replaced the collodion wet process with a gelatin emulsion which could be dried and was not required to be used immediately. Gelatin emulsions have, through they years, been continually improved in quality and speed. Gelatin is still the best medium known for making photographic emulsions.

Gelatin for photographic use is primarily Type B alkaline processed gelatin, especially for emulsion preparation. Type A gelatin has limited application for top coating and subbing. Although cattle hides have been used, Type B photographic gelatin is generally made from ossein derived from bone. Preparation and extraction of the raw materials are done under carefully controlled conditions to produce gelatin with desired photographic properties, such as varying degrees of sensitivity or inertness with minimal fogging properties.

* Measured at 6.16% gelatin concentration and 40-degrees C
** Measured at 10.0% gelatin concentration and 40-degrees C: gelatin held for 24 hours at 37-degrees C.

Gelatin serves several functions in the preparation of the silver emulsions. It acts as a protective colloid during the precipitation of the silver halides; it is an important factor in controlling the size of the silver halide grains; and it protects the halide grains in the reducing action of the developer so that the reduction of these grains to metallic silver is in proportion to their exposure to light.

Formulas for photographic emulsions and procedures for their preparation can be found in the literature and patents. First, the emulsifying gelatin is dissolved in water and a solution of the required halide salts is added. Next a solution of silver nitrate is carefully added at a specified rate and with constant agitation. The mixture is then heated at a predetermined temperature up to 50-degrees C for a set time. The salts are removed by decantation and washing after the gelatin containing silver halide is precipitated by coagulation. More gelatin and water are added to reconstitute to a proper consistency before chemical sensitization. Variations of the basic process to control silver halide crystal size distribution and size include processes to control nucleation and halide concentration during precipitation.

A final ripening and sensitization then takes place by heating to 50-degrees C or above to reach the maximum or desired sensitivity. This procedure is used for the so-called boiled emulsion.

An ammonia emulsion is prepared similarly, but with the addition of ammonia in the early blending, and the use of lower ripening temperatures.

The emulsion is now ready to be coated on the desired batching film, paper or metal.

Gelatin itself contains natural ingredients which, though present in minute amounts, act as sensitizers in an emulsion. Other substances present naturally act as restrainers; they plan an important role in emulsion preparation to offset reactions which cause fog.

Technical Gelatins

Technical gelatins differ from edible and pharmaceutical gelatins principally in that it is not essential that they meet the rigid specifications for human consumption set forth by the various municipal, state and federal governments to protect the health of the general public.

In many respects these gelatins are similar to edible gelatins. The test methods are generally these me as those used for edible gelatins. Both Type A and Type B gelatins may be used in the various applications that follow, but in certain applications one may be preferred over the other.

Coating and Sizing – Technical gelatins are used in the warp sizing of rayon and acetate yarns. The gelatin size adds strength to the warp and resistance to abrasion so that breakage of the warp is minimized. Gelatin is particularly well suited for this application because of its excellent solubility and film strength. It is applied in aqueous solution along with penetrating oils, plasticizers and antifoam agents before weaving, and later removed during finishing by washing with warm water.

Panama hats are sized with gelatin. Sizing helps preserve the shape of the hat while imparting resistance to water and dirt. An emerging technology involves the use of gelatin to size quartz fibers for space-age fabrics.

Paper Manufacture – Gelatin is used for surface sizing and for coating papers. Either used alone or with other adhesive materials, the gelatin coating creates a smooth surface by filling up the small surface imperfections thereby ensuring improved printing reproduction. Examples include posters, playing cards, wallpaper, and glossy magazine pages.

High quality rag-based papers, such as those used for blueprints and currency, also feature a gelatin size coating. The result is a paper which has good moisture and abrasion resistance as well as good adhesion to printing inks. During manufacture the gelatin coatings are rendered insoluble by treatment with cross-linking agents.

Printing Processes – For over a century, gelatin compositions have been used in printers’ rollers and plate wiping rollers for multicolor presses and offset lithography.

Several photo-printing methods depend on the effect of light on a gelatin film which has been sensitized by treatment with potassium or ammonium dichromate. Examples of printing applications include carbon printing, collotype printing, silk screen printing, and photogravure printing.

Protective Colloidal Applications – Much like edible gelatin is used for clarification of wine, beer and juices, technical gelatins are employed in the removal of extremely fine particles that cannot be settled out or filtered out of chemical solutions. Here gelatin is absorbed onto the surface of the particles effecting a coagulate that may be removed by settling or filtration. Approximately one pound of gelatin per ton of ore is used as a filtration aid during the extraction of uranium ore.

In suspension polymerization gelatin functions to control particle size as well as to prevent coalescence of the particles. About one pound of gelatin is sufficient to control particle size in a 10,000 pound batch of polyvinyl chloride.

Gelatin is added to electroplating baths to control the deposition rate. Similarly, gelatin functions as a zinc brightener by controlling the crystallization of zinc during deposit.

Matches – Gelatin is used almost universally as the binder for the complex mixture of chemicals used to form the head of a match. The surface activity properties of gelatin are important since the foam characteristics of the match head influence the performance of the match on ignition.

Coated Abrasives – Gelatin is used as the binder between the paper substrate and the abrasive particles of sandpaper. During manufacture the paper backing is first coated with a concentrated gelatin solution and then dusted with abrasive grit of the required particle size. Abrasive wheels, disks and belts are similarly prepared. Oven drying and a cross-linking treatment complete the process.

Adhesives – Over the past few decades gelatin-based adhesives have slowly been replaced by a variety of synthetics. Recently, however, the natural biodegradability of gelatin adhesives is being realized. Today, gelatin is the adhesive of choice in telephone book binding and corrugated cardboard sealing.

The tackifying power of gelatin is used to advantage in the manufacture of packaging ribbons, decals, gummed tapes, glass laminates and composition cork gaskets. Hard cover book bindings typically utilize gelatin-based adhesives.

Gelatin Films and Light Filters – Films of various colors are produced with gelatin for use in photographic lighting and theatrical spotlights. Some bottle caps utilize gelatin films for shrunk-on seals.

Cosmetics – Although gelatin is used in cosmetic applications such as creams and wave-set lotions, the use of gelatin hydrolysates is more widespread in personal care products: especially in hair care preparations.

Microencapsulation – Microencapsulation was first introduced commercially in the mid-1950’s as the now well-known carbonless paper wherein a leuco dye material is enclosed in microcapsules coated onto a sheet of paper. When pressure from handwriting or typing breaks the microcapsules, the dye reacts with the coating on the next sheet to form a perfect image of the top sheet.

The applications for microencapsulation are literally limitless: dyes, drugs, flavors and fragrances are a few examples.

Edible Gelatins

Pharmaceutical Gelatins

Photographic Gelatins

Technical Gelatins