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.


  1. Michael Hoy
    September 5

    Hi Alex,

    Very cool site; and of a kind that I really appreciate. I will learn some things here, for sure! Looking forward to creating a lovely meal for you and Sara.


    • Immortal Pestle
      September 5

      Thanks, Michael. That is quite a compliment! We can’t wait to see what new creations you will treat us to 🙂

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