Locust Bean Gum (LBG) (also known as Carob Gum) is obtained form the refined endosperm of seeds from the carob tree Ceretonia Siliqua L.

It is an evergreen tree of the legume family. It grows mainly around the Mediterranean, specially in Spain, Italy, Cyprus, Morocco and Turkey. The tree grows to about 9 mtrs high and is sensitive to very low temperatures. It can take about 10 years before a carob tree starts bearing fruit in commercial quantities. The tree bears fruit in January / February, fruiting starts in April / May and the pods are ready by about September / October.

The seeds are contained in a dark brown pod. After the pods are kibbled (mechanically broken), the seeds are removed. The pods are rich in sugars and proteins and used as animal feed or made in to carob powder which is used as a cocoa substitute.

The seeds are dehusked to remove the outer brown coat and the endosperm is separated from the germ by a mechanical process. The endosperm is then ground using various techniques to make powdered Locust Bean Gum.

LBG is a galactomannan polysaccharide with a mannose backbone and side units of galactose. The ratio of mannose : galactose is about 4 : 1. The approximate molecular weight is 300,000 - 360,000.

LBG is hot water soluble and heating is necessary to completely solubilise the gum.