Benders'dictionary of nutrition and food technology

336NSP See non-starch polysaccharides.nubbing Term used in the canning industry for ‘topping andtailing’ of gooseberries.nucellar layer Of wheat, the layer of cells that surrounds theendosperm and protects it from the entry of moisture.nucleation The formation of a nucleus of water molecules that isrequired for ice crystal formation.nucleic acids Polymers of purine and pyrimidine sugar phosphates;two main classes: ribonucleic acid (RNA) and deoxyribonucleicacid (DNA). Collectively the purines and pyrimidinesare called bases. DNA is a double-stranded polymer (the socalled‘double helix’) containing the five-carbon sugar deoxyribose.RNA is a single-stranded polymer containing the sugarribose.Not nutritionally important, since dietary nucleic acids arehydrolysed to their bases, ribose and phosphate in the intestinaltract; purines and pyrimidines can readily be synthesised in thebody, and are not dietary essentials.nucleoproteins The complex of proteins and nucleic acids foundin the cell nucleus.nucleosides Compounds of purine or pyrimidine bases with asugar, most commonly ribose. For example, adenine plus riboseforms adenosine. With the addition of phosphate a nucleotideis formed.nucleotides Compounds of purine or pyrimidine base with asugar phosphate; the monomer units of DNA and RNA. Naturalconstituents of human milk, often used to supplement infantformulae.nug See nigerseed.nuoc mam Vietnamese, Cambodian; fermented fish sauce. Thefish is digested by autolytic enzymes in the presence of salt addedto inhibit bacterial growth.nutmeg Dried ripe seed of Myristica fragrans; mace is the seedcoat (arillus). Both mace and nutmeg are used as flavourings inmeat products and bakery goods.nutraceuticals Term for compounds in foods that are not nutrientsbut have (potential) beneficial effects.See also functional foods.Nutrasweet TM See aspartame.nutricines Biologically active ingredients in animal feedstuff usedto promote nutrition-based health.nutrient density A way of expressing the nutrient content of afood or diet relative to the energy yield (i.e. per 1000 kcal or perMJ) rather than per unit weight.