Benders'dictionary of nutrition and food technology

389processing Any and all processes to which food is subjected afterharvesting, for the purposes of improving its appearance, texture,palatability, nutritive value, keeping properties and ease ofpreparation, and for eliminating micro-organisms, toxins andother undesirable constituents.processing aids Compounds used in manufacturing to enhancethe appeal or utility of a food or component; clarifying and cloudingagents, catalysts, flocculants, filtration aids, crystallisationinhibitors.proctitis Inflammation of the rectum.proctocolitis Inflammation of the colon and rectum.pro-enzyme See zymogen.proglucagon Precursor of the peptide hormone glucagon, synthesisedin pancreatic α-islet cells and endocrine cells of the gastrointestinaltract; post-synthetic modification leads to formationof glucagon, oxyntomodulin and glp-1.progoitrins Substances found in plant foods which are precursorsof goitrogens.programming The idea that nutritional and environmentalfactors in utero or during early post-natal life can modify geneexpression and hence programme metabolism permanently. Seealso epigenetics.pro-insulin The inactive precursor of insulin, in which the A- andB-chains are joined by the c-peptide; the form in which insulinis stored in pancreatic β-islet cells before release. A small proportionof insulin secretion is pro-insulin. A rare variant ofinsulin-dependent diabetes mellitus is due to genetic lack of thepro-insulin converting enzyme (carboxypeptidase e), so thatonly pro-insulin is secreted.prolactin Hormone secreted by the anterior pituitary that stimulatesmilk secretion after childbirth. Also known as lactogenic orluteotrophic hormone, and luteotrophin.prolamins The major storage proteins of the endosperm ofcereals, including gliadin (wheat), zein (maize), hordein (barley)and avenin (oats). Characterised by solubility in 70% alcohol,but not water or absolute alcohol; especially rich in proline andglutamine, low in lysine.proline A non-essential amino acid, abbr Pro (P), M r 115.1, pK a1.95, 10.64, codons CCNu.Promega TM Mixture of long-chain marine fatty acids: eicosapentaenoic(EPA, C20:5 ω3) and docosohexaenoic (DHA,C22:6 ω3) acids.promoter A compound that is not itself carcinogenic, butenhances the activity of a carcinogen if given subsequently.See also cocarcinogen.