Benders'dictionary of nutrition and food technology

43softening of meat when hung, as a result of hydrolysis of connectivetissue proteins. yeast extract is produced by autolysisof yeast.automat Automatic restaurant in which customers place a coin inthe slot to permit them to open glass doors and obtain food, originallydeveloped in Germany; the first in USA was opened byHorn and Hardart in Philadelphia in 1902; the last, in New York,closed in 1991.autopyron Roman; coarse unleavened bread made from bran andonly a little flour, mainly fed to slaves.Autotrak TM See deft.autotrophes Organisms that can synthesise all the compoundsrequired for growth from simple inorganic salts, as distinct fromheterotrophes, which must be supplied with complex organiccompounds. Plants are autotrophes, whereas animals are heterotrophes.Bacteria may be of either type; heterotrophic bacteriaare responsible for food spoilage and disease.autoxidation Radical chain reaction leading to oxidation ofunsaturated fatty acids in fats and oils, forming hydroperoxidesthat decompose to form off-flavour compounds (secondary oxidationproducts).auxin A plant hormone produced by shoot tips, responsible forcontrolling cell growth and differentiation, and frequently usedas a rooting hormone for cuttings. Chemically indoleacetic acidand related compounds.auxotrophe Mutant strain of micro-organism that requires one ormore nutrients for growth that are not required by the parentorganism. Commonly used for microbiological assay of vitamins,amino acids, etc.availability Also known as bioavailability or biological availability.In some foodstuffs, nutrients that can be demonstrated to bepresent chemically may not be available, or only partially so,when they are eaten. This is because the nutrients are chemicallybound in a form that is not susceptible to enzymic digestion,although it is susceptible to the strong acid or alkali hydrolysisused in chemical analysis. For example, the niacin in cerealgrains, calcium bound to phytic acid, and lysine combined withsugars in the Maillard complex (see maillard reaction), are allbiologically unavailable.See also available lysine.available carbon dioxide See baking powder; flour, self-raising.available lysine Not all of the lysine in proteins is biologicallyavailable, since some is linked through the ε-amino group, eitherto sugars in the Maillard complex (see maillard reaction), or to