Acid Sour or sharp tasting compound that counts citrus juice and vinegar among its number. The degree of acidity is measured using a special index called the pH scale that has a maximum value of 14. Acids are classified as compounds ranking below 7.
Agar A substance isolated from algae that is used in the kitchen as a gelling and thickening agent. It is composed of two different compounds: agarose and agaropectin. It is commonly used in jellies, jams, puddings, and custards.
Amino acid Organic molecule containing both an amino group (2NH2) and an acid group ; the basic building block of proteins.
Amylase Enzyme that breaks down or hydrolyzes starch.
Amylopectin Highly branched-chain fraction of starch.
Amylose Straight-chain fraction of starch.
Antioxidant Substance that retards oxidative rancidity in fats by becoming oxidized itself and stopping a chain reaction.
Aroma Distinctive, pleasant fragrance or odor.
Astringent Shrinking or contracting of tissues in the mouth to produce a puckery effect.
Boiling point Temperature at which the atmospheric pressure is equal to the vapor pressure of a liquid and an equilibrium is established.
Browning reactions An umbrella term for a number of different processes which all ultimately turn food visibly brown. These include two blanket categories: enzymatic and non-enzymatic browning. The enzymatic browning of bananas or tea involve different chemical pathways to non-enzymatic browning such as the Maillard reaction or caramelisation.
Buffer Substance that resists change in acidity or alkalinity.
Caramelisation The set of chemical processes that occur when sugars such as fructose, glucose, and sucrose are heated to the point where they begin to degrade and react with themselves and one another. Caramelisation is one of the “non-enzymatic browning reactions” in cooking and contributes colour and flavour to dishes through the creation of compounds such as acetaldehyde (sherry-like aroma), acetic acid (vinegar), diacetyl (buttery aroma), ethyl acetate (ripe fruit), furan (nutty aroma), and maltol (toast-like aroma).
Carbohydrates Organic compounds containing carbon, hydrogen, and oxygen; simple sugars and polymers of simple sugars.
Catalyst Substance that affects the rate of a chemical reaction without being used up in the reaction.
Chymosin Enzyme from the stomach that clots milk; previously called rennin.
Coagulation Usually refers to a change in or denaturation of a protein that results in hardening or precipitation. Often accomplished by heat or mechanical agitation.
Colloid Usually refers to the state of subdivision of dispersed particles; intermediate between very small particles in true solution and large particles in suspension. Proteins and pectins are usually colloidal.
Crystallization Process of forming crystals that result from chemical elements solidifying with an orderly internal structure.
Denaturation Changing of a protein molecule, usually by the unfolding of the chains, to a less soluble state.
Dextrinization Breakdown of starch molecules to dextrins by dry heat.
Dextrins Polysaccharides resulting from the partial hydrolysis of starch.
Disaccharide Carbohydrate made up of two simple sugars (monosaccharides) linked together. Table sugar (sucrose) is a disaccharide.
Disperse To distribute or spread throughout some other substance.
Dispersed phase Separated or particle component in a dispersion.
Dispersion System composed of dispersed particles in a dispersion medium.
Dispersion medium Continuous medium in which particles are dispersed.
Emulsifier Surface-active agent that acts as a bridge between two immiscible liquids and allows an emulsion to form.
Emulsion Dispersion of one liquid in another with which it is usually immiscible.
Enzymatic browning The browning of vegetables, fruits, and other plants due to the action of the enzyme polyphenol oxidase on polyphenols in the presence of oxygen. The discolouration of bananas, avocados, and apples is all due to enzymatic browning
Enzyme A type of large molecule, generally a protein, that is produced by living cells for very specifically tailored biological processes. Examples include amylase, which breaks down starch, and polyphenoloxidase, which catalyzes enzymatic browning.
Ester Chemical combination of an alcohol and an organic acid. Fats are esters of glycerol and three fatty acids.
Fatty acids Organic acids made up of chains of carbon atoms with a carboxyl group on one end; three fatty acids combine with glycerol to make a triglyceride.
Fermentation Transformation of organic substances into smaller molecules by the action of a microorganism; yeast ferments glucose to carbon dioxide and alcohol.
Foam Dispersion of a gas in a liquid.
Gel Colloidal dispersion that shows some rigidity and keeps the shape of the container in which it has been placed.
Gelatinization Swelling and consequent thickening of starch granules when heated in water.
Gluten Elastic, tenacious substance formed from the insoluble gliadin and glutenin proteins of certain flours during dough development.
Glycerol Three-carbon organic compound (an alcohol) that combines with fatty acids to produce fats (triglycerides).
Gram Basic unit of weight in the metric system; 28.35 grams equal 1 ounce and 453.59 grams equal 1 pound.
Gustatory Having to do with the sense of taste.
Homogenize To break up particles into small, uniform-size pieces. Fat in milk may be homogenized.
Hydration Process of absorbing water.
Hydrogenation Process in which hydrogen is combined chemically with an unsaturated compound such as an oil. Hydrogenation of oil produces a plastic shortening.
Hydrolysis Chemical reaction in which a molecular linkage is broken and a molecule of water is utilized. Starch is hydrolyzed to produce glucose; water is a necessary component of the reaction.
Hydrophilic Attracted to water.
Hygroscopic Tending to absorb water readily.
Immiscible Not capable of being mixed.
Inversion Breakdown of sucrose to its component monosaccharides, glucose and fructose.
Irradiation Process in which food is exposed to radiant energy.
Kilocalorie Amount of heat required to raise the temperature of 1 kilogram (1,000 grams) of water 1?C; a unit of energy.
Kinetic energy Energy created by the very rapid movement of small molecules or ions in a liquid.
Lecithin Fatty substance containing two fatty acids esterified to glycerol along with phosphoric acid and a nitrogen-containing compound; a phospholipid.
Maillard reaction A non-enzymatic browning reaction in which a protein or amino acid and certain sugars such as glucose, lactose, maltose, and galactose combine to give a huge array of flavourful and coloured products. The Maillard reaction is most important in high protein foods.
Minerals Inorganic substances; noncarbon compounds; ash.
Monoglyceride Glycerol esterified to one fatty acid.
Monosaccharides Simple sugars, for example, glucose, fructose, and galactose.
Olfactory Having to do with the sense of smell.
Opaque Not reflecting or giving out light; not clear.
Organic Pertaining to carbon compounds.
Osmosis Movement of water through a semipermeable membrane from an area of low concentration of solute to an area of higher concentration to equalize the osmotic pressure created by differences in concentration.
Oxidases Enzymes that catalyze oxidation reactions.
Oxidation Gain in oxygen or loss of electrons.
Pasteurization Mild heat treatment to destroy vegetative microorganisms; not complete destruction of microbes.
Pectin Polysaccharide composed of galacturonic acid subunits, partially esterified with methyl alcohol, and capable of forming a gel.
pH Expression of degree of acidity. On a scale from 1 to 14, 7 is neutral, 1 is most acid, and 14 is most alkaline or least acid.
Photosynthesis Formation of carbohydrates in living plants from water and carbon dioxide by the action of sunlight on the green chlorophyll pigment of the leaves.
Plasticity Ability to be molded or shaped.
Polyphenols Organic compounds that include as part of their chemical structures an unsaturated ring with more than one 2OH group on it. These compounds are implicated in certain types of oxidative enzymatic browning in foods.
Polysaccharides Complex carbohydrates containing many simple sugars (monosaccharides) linked together. Starch and pectins are polysaccharides.
Polyunsaturated fatty acid Fatty acid that has two or more double bonds between carbon atoms. A polyunsaturated fat is one that contains a relatively high proportion of polyunsaturated fatty acids.
Reduction Gain of hydrogen or gain of electrons.
Rennet Crude extract from calf stomach containing the enzyme chymosin (previously called rennin).
Retrograde Close association of amylose molecules in a starch gel during aging.
Saturated fatty acid Fatty acid that has no double bonds between its carbon atoms and thus holds all of the hydrogen it can hold. A saturated fat is one that contains a relatively high proportion of saturated fatty acids.
Saturated solution Solution containing all of the solute that it can dissolve at that temperature.
Sol Pourable colloidal dispersion that has not yet set into a gel.
Solubility Amount of a substance that will dissolve in a specified quantity of another substance.
Solute Substance to be dissolved in another substance (called the solvent).
Solution Mixture resulting when a solute is dissolved in a solvent.
Solvent Substance that will dissolve another substance (called the solute).
Spore Encapsulated, resistant form of a microorganism.
Sterilize To destroy microorganisms by heating with steam or dry heat or by boiling in liquid for 20 to 30 minutes.
Substrate Substance on which an enzyme acts or the medium on which microorganisms grow.
Supersaturated solution Solution that has dissolved more solute or dispersed substance than it can ordinarily hold at a particular temperature. The solution is formed by being heated and slowly cooled without disturbance.
Syneresis Separation or weeping of liquid from a gel.
Tactile Having to do with the sense of touch.
Toxin A poison, usually a protein, formed by microorganisms.
Translucent Shining or glowing through; partly transparent.
Viscosity Resistance to flow.
Volatile Readily forming a vapor or gaseous phase.
Volatilization Process of becoming volatile.
Whey Liquid portion of milk remaining after the curd, which is chiefly the protein casein, is precipitated.