Benders'dictionary of nutrition and food technology

380polarimeter, polariscope Instrument used to determine thedegree of rotation of polarised light, as a means of measuringconcentrations of optically active compounds.polarised light Ordinary light vibrates in many planes; afterpassing through a crystal of quartz or a polarising filter, itvibrates in only one plane, i.e. it is polarised.Polenske number Measure of the water-soluble fatty acids in alipid that are not steam volatile.See also kirschner number; reichert–meissl number; steamdistillation.polenta Traditional Italian porridge made from maize meal, oftenwith cheese added. May be further cooked by baking or frying.Also Italian name for coarsely ground maize meal (calledhominy grits in USA).policosanols Long-chain (C24–30) aliphatic alcohols fromhydrolysis of sugar cane wax, that lower LDL cholesterol,increase HDL, prevent platelet aggregation and may inhibitfoam cell formation from macrophages. Trade name Ateromixol.pollack (pollock) White fish, Pollachius virens, also known ascoalfish.pollards See wheatfeed.polony Italian smoked pork and veal sausage, ready to slice andeat; also known as bologna.polydextrose, modified A randomly bonded glucose polymerprepared by heating glucose and sorbitol with citric acid. It ismore resistant to enzymic digestion than normal polysaccharidesand 60% is excreted undigested, so providing only about4kJ (1 kcal)/g; hence termed ‘non-sweetening sucrose replacement’,or bulking agent.polydipsia Abnormally intense thirst; a typical symptom of diabetesmellitus and insipidus.polygalacturonase See pectinase.polyglucose See polydextrose.polymerase chain reaction (PCR) An in vitro method for rapidamplification of specific DNA sequences. Starting from minuteamounts of DNA, repetitive cycles of template denaturation,primer annealing and the extension of the annealed primers byDNA polymerase result in the exponential accumulation of theDNA; 10 6 -fold in 20 cycles, each of which takes 4 min.The basis of DNA fingerprinting techniques, and widely usedfor rapid identification of potentially pathogenic organisms infoods.polymer in oil An index of degradation of oil used in frying bythe formation of viscous polymers of lipids due to heating andoxidation.