Benders'dictionary of nutrition and food technology

371from continuing dietary restriction into adult life, and phenylketonuricwomen require extremely careful dietary control throughpregnancy to avoid severe damage to the fetus’s developingbrain.phenylthiohydantoin Reacts with the amino group of aminoacids; used in separation of amino acids by thin-layer chromatography,and for detection in high-performance liquidchromatography.pheophorbide Product of strong acid hydrolysis of chlorophyll;both the chelated Mg 2+ ion and the phytol side chain are lost.See also chlorophyllide; pheophytin.pheophytin Brown pigment produced from chlorophyll byremoval of the Mg 2+ ion in dilute acid.See also chlorophyllide; pheophorbide.phitosite High-calorie food.phlorizin (phloridzin) A glucoside from the roots and bark ofvarious Rosaceae spp. that inhibits the renal tubular reabsorptionof glucose. Formerly used as an experimental model of diabetesmellitus, but it causes glucosuria and hence hypoglycaemia,rather than the hyperglycaemia and subsequent glucosuria seenin uncontrolled diabetes.phosphatase test A test for the adequacy of pasteurisation ofmilk. The enzyme phosphatase (EC 3.1.3.x), normally present inmilk, is denatured at a temperature slightly higher than thatrequired to destroy most pathogens; therefore the presence ofdetectable phosphatase activity indicates inadequate pasteurisation.The test can detect 0.2% raw milk in pasteurised milk.phosphate additives See polyphosphates.phosphates Salts of phosphoric acid; the form in which theelement phosphorus is normally present in foods and bodytissues.See also polyphosphates.phosphatides See phospholipids.phosphatidic acid Glycerol esterified with two molecules of fattyacid, with the third hydroxyl group esterified to phosphate;chemically diacylglycerol phosphate; intermediates in the metabolismof phospholipids.phosphatidylcholine A phospholipid containing choline; seelecithin.phosphatidylethanolamine A phospholipid containingethanolamine.phosphatidylinositol A phospholipid containing inositol.phosphatidylserine A phospholipid containing serine.phospholipids (phosphatides, phospholipins) Glycerol esterifiedto two molecules of fatty acid, one of which is usually a polyun-