Benders'dictionary of nutrition and food technology

147DE See dextrose equivalent value.debranching enzymes Enzymes that hydrolyse the α-1,6 glycosidebonds that form the branch points in amylopectin. Amyloglucosidase(EC 3.2.1.3) and glucoamylase (EC 3.2.1.20) alsohydrolyse α-1,4 links; pullulanase (EC 3.2.1.41) and isoamylase(EC 3.2.1.68) hydrolyse only α-1,6 links.See also amylases; z-enzyme.debrining Removal of much of the salt used in brining vegetables,to a level that will be acceptable in the final product. Alsoknown as freshening.decimal reduction time (D value) Term used in sterilising cannedfood, etc.; the duration of heat treatment required to reduce thenumber of micro-organisms to one-tenth of the initial value, withthe temperature shown as a subscript, e.g. D 121 is time at 121 °C.defoamer See antifoaming agents.DEFRA UK Department of the Environment, Food and RuralAffairs; web site http://www.defra.gov.uk/.defructum Roman; cooking wine that has been reduced to half itsvolume by boiling.DEFT Direct Epifluorescence Filter Technique for measuringbacterial content of milk and other fluids by passing through afine pore filter to retain bacteria that are then stained with acridineorange to permit fluorimetric quantification. A rapid andsensitive alternative to plating out a sample, culturing and countingthe resultant bacterial colonies. Trade names for the equipmentused include Biofoss, Bactoscan and Autotrak.deglutition The act of swallowing.degumming Removal of proteins, phospholipids, gum, resin, etc.in the refining of oils and fats by the addition of dilute hydrochloricor phosphoric acid, brine or alkaline phosphate solution.Permits recovery of lecithin from the aqueous phase.dehydroascorbic acid The oxidised form of vitamin c which isreadily reduced back to the active form in the body, and thereforehas vitamin activity. Not measured by all methods forvitamin C estimation.See also ascorbic acid.dehydrocanning A process in which 50% of the water is removedfrom a food before canning. The advantages are that the textureis retained by the partial dehydration and there is a saving inbulk and weight.7-dehydrocholesterol Intermediate in the synthesis of cholesterol,and precursor for the synthesis of vitamin d in the skin.dehydrofreezing A process for preservation of fruits and vegetablesby evaporation of 50–60% of the water before freezing. Thetexture and flavour are claimed to be superior to those resulting