Glossary

termMeaning
Allowable/ Acceptable Daily Intake (ADI) The level of a substance such as a food additive that can be ingested daily over a lifetime without health risk. Determined from toxicology tests, a dose is found which gives no observable effect, this is then divided by 100 to give the ADI.
Acidulant A food additive used to impart a tart, acidic taste to a food; may also assist in the setting of gels or to act as preservatives.
Amino acid An organic compound containing both an amino group
(-NH2 ) and a carboxyl group (-COOH); essential component of proteins.
Amylopectin One of the components of starch; amylopectin consists of long chains of glucose units which are branched and linked to one another.
Amylose One of the components of starch; it is a smaller molecule than amylopectin and consists of straight chains of glucose units
Anion A negatively-charged ion.
Antioxidant A substance which slows oxidation.
Anti-caking agent A substance which enables a powder to flow freely.
Artificial sweetener Substances which are not carbohydrates but which have the ability to impart the sensation of sweetness.
Bactericidal A substance (e.g. preservative) having the ability to kill bacteria.
Bacteriostatic A substance (e.g. preservative) having the ability to slow down the growth of bacteria.
Bread/flour improvers Gluten obtained from 'old' flour is stronger and more elastic than the gluten from flour that has just been milled and hence will produce better loaf; this ageing process can be copied by the addition of tiny quantities of agents that are called improvers.
Bulk sweeteners Substances which are often used to replace sugar, due to their ability to provide both bulk and the sensation of sweetness. Commonly referred to as sugar substitutes or sugar free sweeteners. The largest group of commercially available bulk sweeteners is the polyols.
Buffer Substances which are capable of 'mopping up' excess acidity or alkalinity (excess hydrogen ions or hydroxyl ions) to maintain a constant pH.
Bulking aids Additives which add to the bulk of a particular food; often used in slimming products but may also be used to replace more expensive ingredients.
Calories, kilocalories/ kilojoules Units of energy; 1 Calorie = 1 kcal = 4.2 kJ.
Carbohydrate Compounds which contain the elements carbon, hydrogen and oxygen; there is always twice as much hydrogen as there is oxygen. Made up of sub units called simple sugars; carbohydrates are one of the major classes of nutrients; one function in the body is as an energy source.
Chelators Substances capable of combining with free metal ions; they are important in preventing the oxidation of food.
Diabetes A disorder of carbohydrate metabolism caused by a deficiency of insulin.
Emulsifier A substance which allows an emulsion to stay in a stable state.
Emulsion Tiny drops of one liquid spread evenly through a second liquid.
Enzymes Biological catalysts, protein in nature, which control the rate of all biological reactions; some have uses in the production of food.
Ester Formed by the combination of an alcohol with an organic acid; fats and oils are examples of esters.
Esterification The process which produces fats through a combination of glycerol and three fatty acids. Generally, the reaction between an alcohol and a carboxylic acid.
Fatty acid Molecule made up of unbranched hydrocarbon chains having about 14-24 carbon atoms with an acidic group (see saturated/unsaturated fatty acids).
Fats Compounds which contain the elements carbon, hydrogen and oxygen; made up of sub units called glycerol and fatty acids; fats are one of the major classes of nutrients; one function in the body is to provide energy.
Fermentation A process carried out on a carbohydrate source by some microorganisms, particularly yeasts, which produces alcohol and carbon dioxide. Used in brewing and baking.
Firming agents Food additives used to prevent the loss of crispness to fruit and vegetables during processing.
Foam The dispersal of a gas in a liquid.
Food additive Food additives are those substances deliberately added to food by the manufacturer to facilitate processing or to improve the appearance, texture, flavour, keeping quality or nutritional value of foods.
Free radicals Reactive species which usually have an unpaired, or free, electron.
Fungicidal Compound (e.g. preservative) having the ability to kill fungi and moulds.
Gel/gelation Gels are systems where large volumes of liquids can be held stationary by small amounts of solids; gelation can be caused by polysaccharides such as starch or proteins such as gelatin.
Glazing agents Food additives used to produce a glaze which gives a shine and protection to a final product.
Glucose A simple sugar; a monosaccharide; the most common substrate for respiration.
Gluten A protein found in flour; it has stretching and elastic properties which allow it to provide a network within dough which can trap carbon dioxide.
Glycaemic index The glycemic index (GI) compares foods and how quickly they supply glucose to the blood. It indicates their immediate effects on blood sugar levles. Foods that break down quickly and supply sugar to the blood rapidly have a high GI. Foods that supply sugar at a steady rate over a period of time have a low GI value.
Glycerol A sweet, sticky liquid containing three alcohol groups; it can combine with one, two or three fatty acid molecules to give a mono-, di- or tri-glycerides.
Humectant A substance capable of keeping other substances moist; added to food to prevent it from drying out.
Hydrophilic Hydro = water, philic = loving; substances that are hydrophilic will dissolve in water.
Hydrophobic Hydro = wate r, phobic = hating; substances which are hydrophobic will not dissolve in water.
Hygroscopic Capable of absorbing water from the air.
Ions Molecules or atoms which carry a positive (cations) or negative (anions) electrical charge.
Immiscible/miscible Liquids which will not mix to form a homogeneous substance when combined are said to be immiscible, e.g. oil and water; liquids that completely mix on combining are miscible, e.g. water and alcohol.
Lipid A fat or fat-like molecule.
Lipophilic Lipo = fat or lipid, philic = loving; substances which are lipophilic will dissolve in fat.
Microorganism Microscopically small organisms such as viruses, bacteria, protozoa and fungi. Bacteria and fungi are principally responsible for decay in food.
Monomer A small molecule which forms the building block to make a polymer.
Nano- A nanometre (nm) is a millionth of a millimetre (mm), or a billionth of a metre (m).
Nanotechnology Processes involving technology that operates at a very small scale, up to about 100 nm.
Organic compounds Compounds that contain chains of atoms of the element carbon, e.g. proteins, fats and carbohydrates.
Organoleptic Compound able to stimulate the sensation of taste or smell.
Oxidation A chemical reaction which involves at least one of the following: loss of electrons, the gain of oxygen or the loss of hydrogen. (Rust is the result of the oxidation of iron; the oxidation of fats in foods results in rancidity.)
Pectin (E440) A plant polysaccharide capable of producing a gel and hence has important setting properties, particularly, in the production of jams.
pH A measure of acidity or alkalinity.
Phospholipid A lipid containing 2 fatty acid residues and 1 phosphate group attached to the glycerol molecules; these are polar molecules.
Polar Some molecules, such as water, have areas of both positive charge and negative charge. Such molecules are said to be polar due to their unequal distribution of electrons.
Polymer A long chain molecule built up from small units called monomers.
Polyols Abbreviation of “polyhydric alcohols”, previously known as “sugar alcohols” (a misnomer as they are neither sugars or contain alcohol), polyols are a diverse groups of substances that act as bulk sweeteners. They are hydrogenated carbohydrates, which exhibit many of the properties of simple sugars, whilst providing lower calories and a reduced glycaemic impact. All polyols are “toothfriendly”, i.e. they do not cause tooth decay.
Polysaccharide Poly = many, saccharide = sugar; polysaccharides are the carbohydrates made up of many sugar sub units.
Polyunsaturated fatty acids The occurrence of two or more carbon to carbon double bonds in a fatty acid chain will result in a polyunsaturated fatty acid (see saturated fatty acids).
Preservatives Substances capable of slowing down or preventing the reactions of decay.
Proteins Compounds which contain the elements carbon, hydrogen, oxygen, nitrogen and sometimes, but not always, phosphorus and sulphur. Consist of sub units called amino acids; one of the major classes of nutrients having a wide range of biological functions.
Rancidity Process in which fats exposed to the air undergo oxidation and liquefy. Other reactions, such as hydrolysis, take place which result in the release of foul smelling free acids.
Receptors Cells capable of detecting changes or stimuli in the internal or external environment of an organism; in humans the receptors for sight, taste and smell are of particular importance to food manufacturers.
Releasing agents Substances used to coat the inside of baking tins, mixing equipment, etc. to prevent food from sticking.
Resistance A phenomenon where the use of chemicals, such as antibiotics, has led to the selection of individuals in a population which are not affected by the chemical; chemical preservatives have not been known to cause this.
Respiration Process which takes place in the living cells of all plants and animals which releases energy.
Retrogradation When starch is mixed with water it swells and forms a gel; with time, the starch components will re-crystallise and squeeze the water out of the gel; this phenomenon is known as retrogradation and is responsible for the staling process in bread.
Saturated/unsaturated fatty acids Fats are the result of the reaction between an alcohol such as glycerol and, typically, three fatty acid molecules. When carbon atoms are joined to each other by single carbon to carbon bonds, the resulting fatty acid is said to be saturated; as each carbon atom has a full complement of hydrogen atoms. Fats formed from this type of fatty acid will tend to be hard. When there is one carbon to carbon double bond within the fatty acid chain, the fatty acid is described as being monounsaturated; the occurrence of two or mor e carbon to carbon double bonds in the fatty acid chain will result in a polyunsaturated fatty acid. The double bonds mean that the carbon atoms have fewer hydrogen atoms attached to them. Fats formed from this type of fatty acid will be softer. The greater the degree of unsaturation, the softer the fat and, indeed, an oil may be produced. Food manufacturers must take into consideration, the fact that softer fats are naturally more susceptible to oxidation.
Stabilisers Food additives which help to retain the physical and textural properties of food particularly emulsions and low fat systems.
Starch Storage polysaccharide in plants; has important thickening properties.
Surface tension The property of liquids where forces between the molecules near the surface leads to the apparent presence of a film.
Suspension The dispersion of small particles of a solid in a liquid.
Syneresis The loss of water from a gel is called syneresis. It is also an important mechanism in the production of curds in cheese manufacture.
Synergist A substance that is used in conjunction with another substance which results in their performance being enhanced by each other. Their performance together is better than their total effect if they were used separately.
Tenderiser Substance or processes which alter the fibrous structure of meat to make it less tough.
Unsaturated fatty acid Also see fatty acids. When there is one carbon to carbon double bond within the fatty acid chain, the fatty acid is described as being monounsaturated; the occurrence of two or mor e carbon to carbon double bonds in the fatty acid chain will result in a polyunsaturated fatty acid. The double bonds mean that the carbon atoms have fewer hydrogen atoms attached to them. Fats formed from this type of fatty acid will be softer. The greater the degree of unsaturation, the softer the fat and, indeed, an oil may be produced. Food manufacturers must take into consideration, the fact that softer fats are naturally more susceptible to oxidation.
Volatile A liquid which easily evaporates into a gas.
Viscosity A measure of the 'runniness' or 'flow' of a liquid. Water is less viscous or more runny than treacle.

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