Gelatin and collagen glossary

Amino acid

Amino acids are the building blocks of proteins. They join together through peptide bonds to form peptides and longer protein chains.

Bloom strength (gel strength)

A measure of the firmness of a gelatin gel, determined using a standardised test. The Bloom value indicates the force needed to depress a specified plunger into a gel prepared under controlled conditions. A higher Bloom value means a firmer gel under the same test conditions.

Blooming (hydration)

The preparation step in which gelatin absorbs water and swells before being dissolved. Blooming is different from Bloom strength, which measures gel firmness. Follow the preparation instructions for the particular gelatin product.

Bovine gelatin

Gelatin produced from collagen obtained from cattle, commonly from hides or bones. “Bovine” identifies the animal source.

Collagen

A structural protein found in animal connective tissues, including skin, bones, tendons and cartilage. Collagen is the raw material used to produce gelatin and collagen peptides.

Collagen peptides (hydrolysed collagen)

Shorter chains of amino acids produced by hydrolysing collagen. Also called hydrolysed collagen or collagen hydrolysate, they dissolve in water and do not form the same thermoreversible gels as conventional gelatin. They are used in products such as beverages, powders and protein-enriched foods.

Fish gelatin

Gelatin produced from collagen obtained from fish, commonly from skin or scales. Its gelling and melting properties vary with the fish species and processing conditions.

Functional properties

The ways an ingredient contributes to the structure, texture or performance of a product. Gelatin’s functional properties include gelling, binding water, stabilising foams and emulsions, and forming films. Here, “functional” describes how the ingredient performs in a formulation.

Gelatin (gelatine)

A protein ingredient produced through the partial hydrolysis of collagen. It is widely used for its gelling, stabilising and film-forming properties in food, pharmaceutical and other applications. “Gelatin” and “gelatine” are alternative spellings of the same ingredient.

Gelation (gelling)

The process by which a liquid develops a gel structure. As a conventional gelatin solution cools, its protein chains form a network that holds water. Gel formation depends on factors such as gelatin type, concentration, temperature and time.

Gelling temperature

The temperature at which a gelatin solution begins to form a gel as it cools under specified conditions. It varies with gelatin source, grade, concentration and the other ingredients in the formulation.

Hydrocolloid

A substance that interacts with water to thicken a mixture, form a gel or help stabilise a product. Examples include gelatin, starch, agar, pectin, carrageenan and guar gum. Different hydrocolloids have different properties and are not necessarily interchangeable.

Hydrolysis

A chemical reaction that breaks bonds within a larger molecule. In proteins, hydrolysis breaks the peptide bonds linking amino acids, splitting long protein chains into shorter fragments. The reaction is promoted by acids, alkalis or enzymes, often with heat. Partial hydrolysis of collagen produces gelatin, while more extensive, controlled hydrolysis produces collagen peptides.

Hydroxyproline

An amino acid abundant in collagen and present in gelatin and collagen peptides. Measuring hydroxyproline can help estimate collagen-derived material in a sample, although it is not exclusive to collagen.

Instant gelatin

A cold-water-soluble, extremely fine powdered gelatin produced using a special drying technique. It forms a pseudo gel without the usual heating and cooling steps. Products vary in how they disperse, dissolve and set, so follow the manufacturer’s preparation instructions.

Isoelectric point (pI)

The pH at which a protein carries no net electrical charge, because its positive and negative charges balance. At or near the isoelectric point, proteins are generally at their least soluble and least stable in solution, and they interact least with the water and other charged ingredients around them.

Leaf gelatin (sheet gelatin)

Gelatin dried into thin sheets, often used in cooking and pastry making. Sheets are usually softened in cold water before being dissolved. Sheet weights and gel strengths vary, so substitutions should follow the supplier’s guidance.

Marine collagen

A term used for collagen or collagen-derived ingredients sourced from marine organisms, commonly fish. Check the product specification for the precise source and whether the ingredient is collagen, gelatin or collagen peptides.

Melting temperature

The temperature at which a gelatin gel becomes liquid on heating under specified conditions. It depends on the gelatin and formulation; it is not a fixed temperature for all gelatin gels. Gelatin’s melting behaviour contributes to its characteristic melt-in-the-mouth texture.

Molecular weight

A measure of the size of a protein or peptide, expressed in daltons (Da). The higher the molecular weight, the larger the molecule. As a general guide:

• An amino acid has a molecular weight of around 100 Da.
• Peptides typically have molecular weights below 10,000 Da, while proteins generally have higher molecular weights. This is not a strict dividing line.
• Collagen has a molecular weight of approximately 300,000 Da.
• Gelatin typically ranges from 20,000 to 220,000 Da.
• Collagen peptides generally range from 2,000 to 6,000 Da, although some can be as small as 300 Da.

These values are indicative and vary with the source and processing method.

Peptide

A short chain of amino acids linked by peptide bonds, typically containing 2 to 50 amino acids. Longer chains are generally considered proteins.

pH

A measure of the acidity or alkalinity of a gelatin or food system. Neutral pH is 7.0. Commercially prepared gelatin typically has a pH between 4.5 and 6.5.

The Bloom strength of prepared gelatin solutions degrades more rapidly at lower pH levels.

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Porcine gelatin

Gelatin produced from collagen obtained from pigs, commonly from skin. “Porcine” identifies the animal source.

Powdered gelatin

Gelatin supplied as dry powder or granules. Conventional powdered gelatin is usually hydrated in cold water before being dissolved with heat. The quantity required depends on its gel strength and the recipe or formulation.

Protein hydrolysates

Mixtures produced by breaking proteins into smaller peptide chains and, depending on the extent of hydrolysis, free amino acids. Gelatin is partially hydrolysed collagen; collagen peptides undergo further breakdown to produce smaller, soluble chains.

Solubility

The ability of a substance to dissolve in a liquid under specified conditions. Conventional gelatin swells in cold water and dissolves when heated sufficiently. Swelling or dispersing in water is not the same as fully dissolving and does not allow a gel to form. Peptides dissolve in cold water.

Thermoreversible gel

A gel that melts when heated and forms again when cooled. Gelatin gels typically melt at or below body temperature (around 37°C), contributing to their characteristic melt-in-the-mouth texture and flavour release. This combination of properties is a key distinguishing feature of gelatin.

Type A and Type B gelatin

A classification based on the pretreatment used in manufacture. Type A gelatin is produced using acid pretreatment and typically has an isoelectric point around pH 7–9. Type B gelatin manufacture includes alkaline pretreatment and typically has an isoelectric point around pH 4.9–5.8.

The isoelectric point is the pH at which the protein has no net electrical charge. These classifications describe the processing route and should not be used alone to identify the animal source.

Viscosity

A measure of a liquid’s resistance to flow. For gelatin solutions, viscosity depends on factors such as concentration, temperature and molecular size. It is commonly reported in millipascal seconds (mPa·s) under specified test conditions and describes a different property from gel strength.