Benders'dictionary of nutrition and food technology

1011:4-β-Glucan cellobiohydrolase (EC 3.2.9.1) is an endohydrolase,yielding soluble cellulose fragments. 1:4-β-Glucan glucanohydrolase(EC 3.2.1.4) is an exohydrolase, yielding cellobiose.β-Glucosidase (EC 3.7.1.21) catalyses the hydrolysis of cellobioseto glucose.Cell-free preparations of cellulase from Trichoderma spp.(especially the mesophilic fungus T. resie) are used to liquefyfruit pulps, and to prepare glucose syrups from waste cellulosefrom pulp mills, etc.cellulose A polysaccharide of glucose units linked β-1,4 whichis not hydrolysed by mammalian digestive enzymes. The maincomponent of plant cell walls, but does not occur in animaltissues. It is digested by bacterial cellulase, and hence onlyruminants and animals that have a large caecum have an adequatepopulation of intestinal bacteria to permit them to digestcellulose to any significant extent. There is little digestion of cellulosein the human large intestine; nevertheless, it serves a valuablepurpose in providing bulk to the intestinal contents, and isone of the major components of dietary fibre (see fibre, dietary)or non-starch polysaccharides.See also cellulose, microcrystalline.cellulose derivatives A number of chemically modified forms ofcellulose are used in food processing for their special properties,including:(1) Carboxymethylcellulose (E-466), which is prepared from thepure cellulose of cotton or wood. It absorbs up to 50 timesits own weight of water to form a stable colloidal mass. It isused, together with stabilisers, as a whipping agent, in icecream, confectionery, jellies, etc., and as an inert filler in‘slimming aids’.(2) Methylcellulose (E-461), which differs from carboxymethylcellulose(and other gums) since its viscosity increases withincreasing temperature rather than decreasing. Hence it issoluble in cold water and forms a gel on heating. Used as athickener and emulsifier, and in foods formulated to be lowin gluten.(3) Other cellulose derivatives used as emulsifiers and stabilisersare hydroxypropylcellulose (E-463), hydroxypropylmethylcellulose(E-464) and ethylmethylcellulose(E-465).cellulose, microcrystalline Partially hydrolysed cellulose usedas a filler in slimming and other foods (E-460).