Food Technology Glossary

The aggregation of denatured protein molecules into an insoluble network, following denaturation and driven by newly exposed hydrophobic groups.

Deterioration of fats producing off-flavours. Hydrolytic rancidity releases free fatty acids by lipase or water; oxidative rancidity is a free-radical chain reaction with oxygen at unsaturated bonds.

A sugar with a free aldehyde or ketone group that can act as a reducing agent — glucose, fructose, lactose and maltose are reducing sugars. Sucrose is not, because both anomeric carbons are involved in the glycosidic bond.

The re-association of gelatinised starch chains, mainly amylose, into an ordered crystalline structure during cooling and storage, expelling water (syneresis).

The irreversible swelling of starch granules when heated in water above a characteristic temperature, in which the crystalline structure is lost, amylose leaches out and viscosity rises sharply.

The ratio of the vapour pressure of water in a food to the vapour pressure of pure water at the same temperature. It measures how much water is available for microbial growth and chemical reactions — not how much water is present.

The soluble milk proteins remaining after casein removal — chiefly β-lactoglobulin and α-lactalbumin. Heat-labile but acid-stable.