Benders'dictionary of nutrition and food technology

196flummery Old English pudding made by boiling down the waterfrom soaked oatmeal until it becomes thick and gelatinous.Similar to frumenty. Dutch flummery is made with gelatine orisinglass and egg yolk; Spanish flummery with cream, rice flourand cinnamon.Fluon See PTFE.fluorescence The ability to absorb light at one wavelength andemit at another within 10–100 ns.See also fluorimetry.fluorescence immunoassay Sensitive and specific analytical techniquefor determination of analytes present at very low concentrationsin biological samples; the antibody is labelled with asubstrate that yields a fluorescent product, but in such a way thatit does not act as a substrate for the enzyme when the antigen(analyte) is bound. Therefore only free antibody will yield thefluorescent product when the enzyme is added. Unlike radioimmunoassay,does not require separation of bound and freeantigen.See also elisa.fluoridation The addition of fluoride to drinking water.fluoride The ion of the element fluorine. Although it occurs insmall amounts in plants and animals, and has effects on the formationof dental enamel and bones, it is not considered to be adietary essential and no deficiency signs are known.Drinking water containing about 1 part per million of fluorideprotects teeth from decay, and in some areas fluoride is addedto drinking water to achieve this level. Naturally, the fluoridecontent of water ranges between 0.05 and 14 ppm.Water containing more than about 12ppm fluoride can lead tochalky white patches on the surface of the teeth, known asmottled enamel. At higher levels there is strong brown mottlingof the teeth and inappropriate deposition of fluoride in bones,fluorosis.fluorimetry (fluorometry) Sensitive and relatively specific analyticaltechnique dependent on emission of light more or less immediately(within 10–100 ns) after absorption of light by acompound in solution. Both the exciting and emitted wavelengthsare characteristic of the analyte, and the intensity offluorescence is proportional to the concentration of analytepresent.fluorodinitrobenzene (FDNB, dinitrofluorobenzene) Reacts withfree amino groups; commonly used to determine free ε-aminogroups of lysine (and hence available lysine) in proteins.fluorosis Damage to teeth (brown mottling of the enamel) andbones caused by an excessive intake of fluoride.