Food Technology Glossary

A substance that tastes sour and has a pH below 7. In food, acids come from fruits, curd, or are added on purpose.

The highly branched fraction of starch, with α-1,4 chains joined by α-1,6 branch points roughly every 20–25 units.

The essentially linear fraction of starch, made of α-1,4-linked glucose units. Typically 20–30% of common starches.

A substance that delays oxidative rancidity. Primary antioxidants (BHA, BHT, TBHQ, tocopherols) donate hydrogen to break the radical chain; secondary antioxidants (citric acid, EDTA) chelate pro-oxidant metals.

Thermal degradation of sugars in the absence of amino groups, producing colour and flavour compounds. It requires much higher temperatures than the Maillard reaction.

The main phosphoprotein of milk, about 80% of milk protein, existing as micelles stabilised by κ-casein. Precipitates at pH 4.6 or on rennet action.

The separation of milk into solid lumps (curd) and liquid (whey), caused by acid, heat, or an enzyme changing the milk proteins.

The percentage of galacturonic acid carboxyl groups in pectin that are methyl-esterified.

Loss of a protein's secondary, tertiary and quaternary structure without breaking peptide bonds, caused by heat, pH change, salts, solvents or shear.

A surface-active molecule with hydrophilic and lipophilic regions that lowers interfacial tension and stabilises an emulsion.

A dispersion of one immiscible liquid in another, stabilised by an emulsifier. Oil-in-water as in milk and mayonnaise, or water-in-oil as in butter and margarine.

Browning catalysed by polyphenol oxidase, which oxidises phenolic compounds to quinones that polymerise into brown melanins. It requires oxygen, the enzyme, and a phenolic substrate.