| Term | Definition |
|---|---|
| Gel |
The semi-rigid jelly-like sol that is formed when cooked starch paste is cooled and stored at room temperature. It is usually associated with native starches and acid-thinned starches. |
| Gelatinization |
The destruction of molecular order and irreversible swelling of starch granules under the influence of heat and/or chemicals in an aqueous medium to give a starch paste. During the swelling process amylose tends to leach out of the starch granules and, with amylopectin, becomes hydrated. Viscosity rises and is at a peak when the granules are hydrated to their maximum extent and are in close contact with their neighbors. The granules then rupture, collapse and fragment. Polymer molecules and aggregates are released into the surrounding aqueous medium. Gelatinization is, in fact, a multi-step process from the first incipient granule swelling through to complete granule disruption and partial solubilization of the constituent polymers. |
| Gelatinization temperature |
The temperature at which a particular starch gelatinizes to form a starch paste. This depends on starch type, the chemical environment, and several other factors. Values quoted in literature should be taken as approximate because starch gelatinizes over a finite temperature range which can be determined by viscometry, on a microscope hot stage, by observing granule crystallinity under polarized light etc etc. Each technique gives different values. Gelatinization temperature of starches can be changed by physical or chemical pretreatments. Pasting temperature and chemical gelatinization are related concepts. |
| Gelling |
It is used more precisely to denote the conversion of starch paste, on storage and/or cooling, from a fluid paste to a semi-solid deformable gel structure. Gelling occurs as the hydrated and dissolved linear amylose molecules in a starch paste associate to form a three dimensional network. |
| Glucose |
A sugar with the molecular formula C6H12O6. It is produced commercially by the first liquefying starch to an intermediate Dextrose Equivalent then continuing the hydrolysis by saccharification with glucoamylase. Glucose (also known as Dextrose) may be crystallized from high dextrose syrup as the monohydrate. |
| Glucose syrup |
Known as corn syrup in USA. Purified concentrated aqueous solution of nutritive saccharides made from starch and having a dextrose equivalent above 20. |
| Granular Instant Starch |
When starch is heated in the presence of limited moisture and an organic solvent, e.g. in aqueous alcohol, the internal crystalline structural order is destroyed but the granule shape and integrity are maintained. When such a starch is dispersed in cold or warm water, swelling occurs followed by viscosity development. Granular Instant Starches have higher and more stable viscosities than conventional pregelatinized starches. |
| Granule (as in starch granule) |
Starch exists in certain plant species in the form of small particles known as granules. These granules have a characteristic size and shape depending on the particular species involved. Microscopic examination may be used to identify starch type by reference to standard images of different starch granule types. |
| GRAS - Generally Recognizes as Safe |
A classification of foods and food ingredients by the Food and Drug Administration in the USA. |