Benders'dictionary of nutrition and food technology

349overweight Excessive accumulation of body fat, but not sogreat as to be classified as obesity. Defined as body mass index25–30 kg/m 2 .ovomucin A carbohydrate–protein complex in egg white, responsiblefor the firmness of egg white, 1–3% of the total solids.ovomucoid A protein of egg white, 12% of the total solids. Itinhibits the digestive enzyme trypsin, but is inactivated by gastricpepsin.oxalic acid A dicarboxylic acid, chemically COOH—COOH. Poisonousin large amounts; present especially in spinach, chocolate,rhubarb and nuts. The toxicity of rhubarb leaves is due to theirhigh content of oxalic acid.Reports that very high intakes of vitamin c (several grams perday) lead to formation of oxalic acid were based on detection ofoxalic acid in urine, but this was almost certainly formed aftercollection; there is no known pathway for formation of oxalicacid from ascorbate.Genetic diseases of glycine and glyoxylate metabolism leadto hyperoxaluria, as a result of reduction of glyoxylate tooxalate by lactate dehydrogenase (EC 1.1.1.27).Oxfam Non-governmental organization concerned with faminerelief and improvement of food resources in less developedcountries. Originally founded by Gilbert Murray in 1942 asOxford Committee for Famine Relief. Web site http://www.oxfam.org.uk/.oxidases (oxygenases) Enzymes that oxidise substrates by reactionwith oxygen to form water or hydrogen peroxide. They thusdiffer from dehydrogenases, which oxidise substrates by transferof hydrogen to a coenzyme. Mixed function oxidases introduceoxygen into both the substrate and water.oxidation The chemical process of removing electrons from anelement or compound (e.g. the oxidation of iron compoundsfrom ferrous, Fe 2+ to ferric, Fe 3+ ), frequently together with theremoval of hydrogen ions (H + ). The reverse process, the additionof electrons or hydrogen, is reduction. In biological oxidationand reduction reactions, cytochromes act to transfer electrons,while coenzymes derived from the vitamins niacin and vitaminb 2 are hydrogen carriers, transferring both electrons and H + ions.oxidative phosphorylation The formation of atp from ADP andphosphate in the mitochondrion, linked to the electrontransport chain and the oxidation of metabolic fuels.See also uncoupling protein.Oxo TM A dried preparation of hydrolysed meat, meat extract, saltand cereal in cube form, used as a drink or gravy.