Locust bean gum (LBG, carob gum, carob bean gum, carobin, E410) is a

galactomannan Galactomannans are polysaccharides consisting of a mannose backbone with galactose side groups, more specifically, a (1-4)-linked beta-D-mannopyranose backbone with branchpoints from their 6-positions linked to alpha-D-galactose, (i.e. 1-6-linked ...

vegetable gum Natural gums are polysaccharides of natural origin, capable of causing a large increase in a solution's viscosity, even at small concentrations. They are mostly botanical gums, found in the woody elements of plants or in seed coatings. Human u ...

extracted from the

seed A seed is an embryonic plant enclosed in a protective outer covering, along with a food reserve. The formation of the seed is a part of the process of reproduction in seed plants, the spermatophytes, including the gymnosperm and angiospe ...

s of the

carob tree The carob ( ; ''Ceratonia siliqua'') is a flowering evergreen tree or shrub in the Caesalpinioideae sub-family of the legume family, Fabaceae. It is widely cultivated for its edible fruit pods, and as an ornamental tree in gardens and lands ...

and used as a

thickening agent 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 t ...

(gelling agent) in

food technology Food technology is a branch of food science that deals with the production, preservation, quality control and research and development of the food products. Early scientific research into food technology concentrated on food preservation. Nic ...

Production

Locust bean gum is extracted from the seeds of the carob tree, which is native to the

Mediterranean region In biogeography, the Mediterranean Basin (; also known as the Mediterranean Region or sometimes Mediterranea) is the region of lands around the Mediterranean Sea that have mostly a Mediterranean climate, with mild to cool, rainy winters and wa ...

. In 2016, nearly 75% of global production came from Portugal, Italy, Spain and Morocco. The seeds are contained within long pods that grow on the tree. First, the pods are

kibbled A mill is a device, often a structure, machine or kitchen appliance, that breaks solid materials into smaller pieces by grinding, crushing, or cutting. Such comminution is an important unit operation in many processes. There are many different ...

to separate the seed from the pulp. Then, the seeds have their skins removed by an acid or heat treatment. Acid treatment yields a lighter coloured gum than heat treatment.^:222 the deskinned seed is then split and gently milled. This causes the brittle

germ Germ or germs may refer to: Science * Germ (microorganism), an informal word for a pathogen * Germ cell, cell that gives rise to the gametes of an organism that reproduces sexually * Germ layer, a primary layer of cells that forms during embry ...

to break up while not affecting the more robust

endosperm The endosperm is a tissue produced inside the seeds of most of the flowering plants following double fertilization. It is triploid (meaning three chromosome sets per nucleus) in most species, which may be auxin-driven. It surrounds the embryo and ...

. The two are separated by

sieving A sieve, fine mesh strainer, or sift, is a device for separating wanted elements from unwanted material or for controlling the particle size distribution of a sample, using a screen such as a woven mesh or net or perforated sheet material. ...

. The separated endosperm can then be milled by a roller operation to produce the final locust bean gum powder. Alternatively, the gum can be extracted from the seeds with water, precipitated with alcohol, filtered, dried and milled, to give a very pure "clarified" locust bean gum.^:223

Chemistry

Locust bean gum occurs as a

white White is the lightest color and is achromatic (having no hue). It is the color of objects such as snow, chalk, and milk, and is the opposite of black. White objects fully reflect and scatter all the visible wavelengths of light. White on ...

to yellow-white

powder A powder is a dry, bulk solid composed of many very fine particles that may flow freely when shaken or tilted. Powders are a special sub-class of granular materials, although the terms ''powder'' and ''granular'' are sometimes used to distin ...

. It consists chiefly of high-

molecular-weight The molecular mass (''m'') is the mass of a given molecule: it is measured in daltons (Da or u). Different molecules of the same compound may have different molecular masses because they contain different isotopes of an element. The related quanti ...

hydrocolloidal A colloid is a mixture in which one substance consisting of microscopically dispersed Solubility, insoluble particles is suspension (chemistry), suspended throughout another substance. Some definitions specify that the particles must be disperse ...

polysaccharide Polysaccharides (), or polycarbohydrates, are the most abundant carbohydrates found in food. They are long chain polymeric carbohydrates composed of monosaccharide units bound together by glycosidic linkages. This carbohydrate can react with wa ...

s, composed of

galactose Galactose (, '' galacto-'' + '' -ose'', "milk sugar"), sometimes abbreviated Gal, is a monosaccharide sugar that is about as sweet as glucose, and about 65% as sweet as sucrose. It is an aldohexose and a C-4 epimer of glucose. A galactose molec ...

and

mannose Mannose is a sugar monomer of the aldohexose series of carbohydrates. It is a C-2 epimer of glucose. Mannose is important in human metabolism, especially in the glycosylation of certain proteins. Several congenital disorders of glycosylation ...

units combined through glycosidic linkages, which may be described chemically as galactomannan. It is dispersible in either hot or cold water, forming a sol having a pH between 5.4 and 7.0, which may be converted to a gel by the addition of small amounts of

sodium borate Sodium borate is a generic name for any salt of sodium with an anion consisting of boron and oxygen, and possibly hydrogen, or any hydrate thereof. It can be seen as a hydrated sodium salt of the appropriate boroxy acid, although the latter may n ...

. Locust bean gum is composed of a straight backbone chain of D-mannopyranose units with a side-branching unit of D-galactopyranose having an average of one D-galactopyranose unit branch on every fourth D-mannopyranose unit.

Food science

The bean, when made into powder, is sweet—with a flavor similar to chocolate—and is used to sweeten foods and as a chocolate substitute, although this carob powder is produced from the fruit pod after removal of seeds, while the gum is produced from the seeds themselves. It is also used in pet foods and inedible products such as mining products, paper making, and to thicken textiles. It is used in cosmetics and to enhance the flavor of cigarettes. Shoe polish and insecticides also have locust bean gum powder as an additive. It is soluble in hot water.Martin Chaplin
Locust bean gum
, London South Bank University, web page.

References

{{reflist Edible thickening agents Natural gums Food stabilizers E-number additives de:Johannisbrotkernmehl

Production

Chemistry

Food science

See also

References