Functional Properties of Food – Glossary

amino acid: A unit from which proteins are constructed.

casein: A family of proteins commonly found in milk.

catalyse: To increase the rate of a chemical reaction (usually the function of enzymes).

cellulose: A polysaccharide which forms the structure of plant cells.

dipeptide: Two amino acids joined together.

emulsifier (emulgent): A substance which helps mixtures of oils and water to coalesce (mix).

emulsion: A fine mixture of two liquids (e.g. oil and water) which would not normally mix.

enzyme: A specialised protein that regulates chemical reactions.

fatty acid: Molecules of hydrogen and carbon. 3 of these, along with glycerol, form a triglyceride.

gliadins: A class of proteins found within grains (including wheat). Forms one part of the gluten structure.

glutelins: A class of proteins found within grains, alongside gliadins. Forms the gluten structure, along with gliadins.

glutenin: A specific glutelin that is commonly found in wheat.

glycerol: A molecule that binds to 3 fatty acids to form a triglyceride.

hydrocarbon: An organic chemical compound consisting entirely of hydrogen and carbon.

hydrogenation: The chemical process of adding hydrogens to unsaturated fatty acids to make them saturated.

hydrolysis: The reaction between a chemical and water, causing it to split apart.

hydrophilic: Something with an affinity for water. Tends to form a solution in water.

hydrophobic: Something averse to water, will not form a solution in water and will tend to clump together.

hydroxyl group: A group with the chemical formula ‘-OH’, where ‘-‘ suggests it is bound to something else.

hygroscopic: Having a tendency to absorb moisture.

interesterification: A process by which fatty acids are ‘swapped’ between triglycerides. This results in a fat with different properties (e.g. melting point).

lecithin: An emulsifying agent found in many foods including egg yolk and soya.

mucilage: An emulsifying agent found in many foods (commonly mustard seeds).

pectin: A polysaccharide naturally occurring in some fruits, has the property of forming a gel (e.g. jam)

peptide bond: A chemical bond formed between two amino acids, joining them together.

polypeptide: Many amino acids joined together.

proteolytic: Having the ability to ‘break’ proteins.

pyrodextrin: Short carbohydrate chains, produced by the dry heating of starch.

reducing sugar: A sugar with a chemical group that is free to react as a reducing agent (in the context of this course, these are reacting with amino acids)

rennet: A mixture of proteolytic enzymes. Used in industry to curdle casein for cheese production.

starch: A polysaccharide which forms a key store of energy in plant cells.

triglyceride: The main form of fat found in foods. Made up from 3 fatty acids and 1 molecule of glycerol.

whey: The liquid remaining after the production of cheese or casein.