Tự điển Food Science, Technology And Nutrition - Vần N

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324 mycotoxins Compounds produced by ﬁlamentous fungi (and so exclude mushroom toxins) that may accumulate to harmful levels in foods without any adverse effect on the ﬂavour or appearance of the food; many are acutely or chronically toxic or carcinogenic. The most important are: aﬂatoxins (produced by Aspergillus spp.), ochratoxins (Aspergillus and Penicillium spp.), monoliformin (Fusarium spp.), patulin (Aspergillus and Penicil- lium spp.) and ergot alkaloids formed by Claviceps purpurea growing on rye. myenteron Muscle layers of the intestine, a layer of circular muscles inside a layer of longitudinal muscles, responsible for peristalsis. myocardial infarction Damage to heart muscle due to ischaemia (failure of the blood supply from the coronary arteries). myoﬁbril See muscle. myoglobin haem-containing oxygen binding protein in muscle. Responsible for the red colour of fresh meat, oxidised to brown metmyoglobin as meat ages, or on cooking. When meat is cured (see meat, curing) with nitrite, the myoglobin is converted to the bright red nitrosomyoglobin. myo-inositol See inositol. myosin The major protein of muscle, about 40% of the total. A globulin, insoluble in water but soluble in salt solution. myristic acid A saturated fatty acid with 14 carbon atoms (C14:0). myrosinase The enzyme (thioglycosidase, EC 3.2.3.1) in mustard seed and horseradish that hydrolyses myrosin or sinigrin to glucose and allyl isothiocyanate, the pungent principle. Mysore ﬂour A blend of 75% tapioca and 25% peanut ﬂour. mysost See gjetost. myxoedema Severe hypothyroidism (underactivity of the thyroid gland, see thyroid hormones) in adults; the name is derived from pufﬁness of hands and face due to thickening of skin. Signs include coarsening of the skin, intolerance of cold, weight gain and dull mental apathy, as well as reduced basal metabolic rate. myxoxanthin carotenoid pigment in algae with vitamin a activity. N naartje Afrikaans; a small tangerine; see citrus fruit. NAASO North American Association for the Study of Obesity, now called the Obesity Society; web site http://www.naaso.org/. NAD, NADP Nicotinamide adenine dinucleotide and nicoti- namide adenine dinucleotide phosphate, the coenzymes derived
325 from niacin. Involved as hydrogen acceptors / donors in a wide variety of oxidation and reduction reactions. NAEL See no adverse effect level. nalidixic acid Quinolone antibiotic used to treat intestinal (and urinary tract) infections. nam pla Thai; salted paste made from shrimps and small ﬁsh. nan Indian ﬂat bread, an egg dough prepared with white ﬂour and leavened with sodium bicarbonate, normally baked in a tandoor (see tandoori). nanoﬁltration A membrane process to separate particles with molecular weights from 300–1000 Da, using lower pressures than reverse osmosis (see osmosis, reverse). naphthoquinone The chemical ring structure of vitamin k; the various chemical forms of vitamin K can be referred to as sub- stituted naphthoquinones. naringenin See naringin. naringin A glycoside (trihydroxyﬂavonone rhamnoglucoside) found in grapefruit, especially in the immature fruit. Extremely bitter: dilutions of 1 part in 10 000 parts of water can be detected. Sometimes found in canned grapefruit segments as tiny, white beads. Hydrolysed to the aglycone, naringenin, which is not bitter. naseberry Alternative name for sapodilla. nashi See pear, nashi. nasogastric tube Fine plastic tube inserted through the nose and thence into the stomach for enteral nutrition. nasturtium Both the leaves and seeds of Tropaeolum ofﬁcinalis can be eaten; they have a hot ﬂavour. The seeds can be pickled as a substitute for capers, and the ﬂowers can be used to deco- rate salads. nata Filipino; thick gelatinous ﬁlm grown on the surface of coconut, sugarcane or fruit juice by fermentation with the acetic acid bacterium Acetobacter aceti, which produces an extracellu- lar cellulose polymer. Eaten as a dessert. natamycin (or pimaricin) A polyene antifungal agent, from Strep- tomyces natalensis, used as a coating on the surface of cheeses to prevent the growth of mould or yeast. national ﬂour See ﬂour, wheatmeal. natriuretic Any compound that promotes excretion of sodium salts in the urine; most diuretics are natriuretics. natto Japanese; soya bean fermented using Bacillus natto. Composition /100 g: water 55 g, 887 kJ (212 kcal), protein 17.7 g, fat 11 g (of which 16% saturated, 24% mono-unsaturated, 61% polyunsaturated), carbohydrate 14.4 g (3.6 g sugars), ﬁbre 5.4 g, ash 1.9 g, Ca 217 mg, Fe 8.6 mg, Mg 115 mg, P 174 mg, K
326 729 mg, Na 7 mg, Zn 3 mg, Cu 0.7 mg, Mn 1.5 mg, Se 8.8 µg, vitamin K 23.1 mg, B1 0.16 mg, B2 0.19 mg, B6 0.13 mg, folate 8 µg, pan- tothenate 0.2 mg, C 13 mg. NatualTM Low cholesterol cheese, prepared by use of cyclodextrin. natural foods A term widely used but with little meaning and sometimes misleading since all foods come from natural sources. No legal deﬁnition seems possible but guidelines suggest the term should be applied only to single foods that have been sub- jected only to mild processing, i.e. largely by physical methods such as heating, concentrating, freezing, etc., but not chemically or ‘severely’ processed. natural water See water, mineral. nature-identical Term applied to food additives, including vita- mins, that are synthesised in the laboratory and are identical to those that occur in nature. N balance (equilibrium) See nitrogen balance. NCHS standards Tables of height and weight for age used as ref- erence values for the assessment of growth and nutritional status of children, based on data collected by the US National Center for Health Statistics. The most comprehensive such set of data, and used in most countries of the world. N conversion factor See nitrogen conversion factor. NDGA See nordihydroguaiaretic acid. NDpCal See net dietary protein–energy ratio. neat’s foot Ox or calf’s foot used for making soups and jellies. Now called cow heels. Neat’s foot oil is obtained from the knuckle bones of cattle; used in leather working and for canning sardines. Necator Genus of hookworms that are parasitic in the small intestine; the human parasite is N. americanus. necrosis Death of cells or tissues in an unprogrammed manner, in response to toxicity or ischaemia. See also apoptosis. nectarine Smooth-skinned peach (Prunus persica var. nectarina). Composition /100 g: (edible portion 91%) water 87.6 g, 184 kJ (44 kcal), protein 1.1 g, fat 0.3 g, carbohydrate 10.6 g (7.9 g sugars), ﬁbre 1.7 g, ash 0.5 g, Ca 6 mg, Fe 0.3 mg, Mg 9 mg, P 26 mg, K 201 mg, Zn 0.2 mg, Cu 0.1 mg, Mn 0.1 mg, vitamin A 17 µg RE (378 µg carotenoids), E 0.8 mg, K 2.2 mg, B1 0.03 mg, B2 0.03 mg, niacin 1.1 mg, B6 0.03 mg, folate 5 µg, pantothenate 0.2 mg, C 5 mg. A 150 g serving (1 fruit) is a source of Cu, vitamin E, C. Neeld–Pearson reaction See carr–price reaction. neep Scottish name for root vegetables; now used for turnip (and sometimes for swede in England).
327 NEFA Non-esteriﬁed fatty acids. negus Drink made from port or sherry with spices, sugar and hot water. NEL See no effect level. nematode Any one of a large group of unsegmented worms; most are free-living, but some, including hookworms and pinworms, are intestinal parasites. neohesperidin dihydrochalcone (NEO-DHC) A non-nutritive sweetener, 1000 times as sweet as sucrose; formed by hydro- genation of the naturally occurring ﬂavonoid neohesperidin. neomycin Broad spectrum aminoglycoside antibiotic isolated from Streptomyces fradii that is poorly absorbed from the gas- trointestinal tract and is used to treat persistent intestinal bac- terial infections. neonate Literally new-born, used to describe infants in the ﬁrst four weeks of life. neotame Synthetic intense sweetener, 8000 times as sweet as sucrose, N-[N-(3,3-dimethylbutyl)-l-α-aspartyl]-l-phenylalanine 1-methyl ester. See also aspartame. nephrocalcinosis Presence of calcium deposits in the kidneys; may result from vitamin d toxicity. neroli oil Prepared from blossoms of the bitter orange by steam distillation. Yellowish oil with intense odour of orange blossom. net dietary protein calories See net dietary protein–energy ratio. net dietary protein–energy ratio (NDpE) A way of expressing the protein content of a diet or food taking into account both the amount of protein (relative to total energy intake) and the protein quality. It is protein energy multiplied by net protein utilisation divided by total energy. If energy is expressed in kcal and the result expressed as a percentage, this is net dietary protein calories per cent, NDpCal%. See also net protein value. net protein ratio (NPR), net protein utilisation (NPU) Measures of protein quality. net protein value A way of expressing the amount and quality of the protein in a food; the product of net protein utilisation and protein content per cent. See also net dietary protein–energy ratio; protein quality. neural tube defect Congenital malformations of the spinal cord caused by failure of the closure of the neural tube in early embry- onic development (before day 28 of gestation). Supplements of folic acid (400 µg/day) begun before conception reduce the risk signiﬁcantly.
328 neuritis Inﬂammatory disease of peripheral nerves. See also neuropathy. neuropathy Any disease of peripheral nerves, usually causing weakness and numbness. See also neuritis. neuropeptide Y A peptide neurotransmitter involved in the control of appetite and feeding behaviour, especially in response to leptin. neutron activation analysis The nuclei of a number of elements will capture a neutron on exposure to a neutron beam, leading to the formation of unstable (radioactive) isotopes which can then be measured by the radiation emitted as they decay. Used for determination of whole body calcium, chlorine and nitrogen. new cocoyam See tannia. New Zealand process Drying process for meat. It is immersed in hot oil under vacuum when it dries to 3% moisture in about 4 h. NFE See nitrogen-free extract. NFLEA US National Food Labelling and Education Act, 1993, the basis of nutrition labelling of foods and health claims that may be made. nham South-east Asian; semi-dry uncooked pork or beef sausage left to undergo lactic acid bacterial fermentation for 4–5 days. niacin (see p. 329) A vitamin; one of the B complex without a numerical designation. Sometimes (incorrectly) referred to as vitamin B3, and formerly vitamin PP (pellagra preventative). Deﬁciency leads to pellagra, photosensitive dermatitis resem- bling severe sunburn, a depressive psychosis and intestinal dis- orders; fatal if untreated. Niacin is the generic descriptor for two compounds in foods that have the biological activity of the vitamin: nicotinic acid (pyridine carboxylic acid) and nicotinamide (the amide of nico- tinic acid). In the USA niacin is sometimes used speciﬁcally to mean nicotinic acid, and niacinamide for nicotinamide. The metabolic function of niacin is in the coenzymes NAD (nicotinamide adenine dinucleotide) and NADP (nicotinamide adenine dinucleotide phosphate), which act as intermediate hydrogen carriers in a wide variety of oxidation and reduction reactions. In cereals niacin is largely present as niacytin, which is not biologically available (see availability); therefore the pre- formed niacin content of cereals is generally ignored when cal- culating intakes. See also niacin equivalents.
329 NIACIN niacinamide American name for nicotinamide, see niacin. niacin equivalents Nicotinamide can be formed in the body from the amino acid tryptophan; on average 60 mg dietary tryptophan is equivalent to 1 mg preformed niacin. The total niacin content of foods is generally expressed as mg niacin equivalents; the sum of preformed niacin (excluding that in cereals, see niacytin) plus one-sixtieth of the tryptophan. niacinogens Name given to protein–niacin complexes found in cereals; see also niacytin. niacin toxicity High doses of nicotinic acid have been used to treat hypercholesterolaemia; they can cause an acute ﬂushing reaction, with vasodilatation and severe itching (nicotinamide does not have this effect, but is not useful for treatment of hyper- cholesterolaemia). Intakes of niacin above 500 mg/day (the ref- erence intake is 17 mg/day) can cause liver damage over a period of months; the risk is greater with sustained release preparations of niacin. niacytin The main form of niacin in cereals. Nicotinic acid ester- iﬁed as nicotinoyl-glucose in oligosaccharides and non-starch polysaccharides; susceptible to alkaline hydrolysis and partially susceptible to acid hydrolysis in the stomach. However, because of variable availability, it is conventional to exclude the niacin content of cereals from calculations of intake. See also niacinogens. nib See chocolate. nibbler Machine for comminution of dry foods using grating action rather than grinding as in mills. niceritol Penta-erythritol tetranicotinate, a derivative of niacin used as a hypolipidaemic agent. nickel A mineral (see mineral, ultratrace) known to be essen- tial to experimental animals, although its function is not known. There is no information on requirements. Metallic nickel is used as a catalyst in the hydrogenation of fats. nicotinamide (niacinamide) One of the vitamers of niacin.
330 nicotinamide adenine dinucleotide (phosphate) See nad. nicotinate, sodium Sodium salt of nicotinic acid; has been used, among other purposes, to preserve the red colour in fresh and processed meats. nicotinic acid (see p. 329) One of the vitamers of niacin. NIDDK National Institute of Diabetes and Digestive and Kidney Diseases; web site http://www.niddk.nih.gov/. nigella Peppery seeds of the wild onion, Nigella sativa. Nigerian berry See serendipity berry. nigerseed Or nug, Guizotia abyssinica; grown in India and Ethiopia as food crop. night blindness Nyctalopia. Inability to see in dim light as a result of vitamin a deﬁciency. See also dark adaptation; vision. nim leaf Sweet nim, an aromatic Indian herb with an aroma resembling that of trufﬂes. ninhydrin test For proteins and amino acids (actually for the amino group). Pink, purple or blue colour is developed on heating the amino acid or peptide with ninhydrin (triketohy- drindene hydrate). nip The gap between rollers in a mill or a moulding/forming machine. nisatidine See histamine receptor antagonists. nisin antibiotic isolated from lactic Streptococcus group N; inhibits some but not all Clostridia; not used clinically. The only antibiotic permitted in the UK to preserve speciﬁed foods. It is naturally present in cheese, being produced by a number of strains of cheese starter organisms. Useful to prolong storage life of cheese, milk, cream, soups, canned fruits and vegetables, canned ﬁsh and milk puddings. It also lowers the resistance of many thermophilic bacteria (see thermophiles) to heat and so permits a reduction in the time and/or temperature of heating when processing canned vegetables. nitrates The inorganic form of nitrogen used by plants; found in soils and included in inorganic fertiliser. Nitrate is a natural con- stituent of crops in amounts sometimes depending on the content in the soil. Also found in drinking water as a result of excessive use of fertilisers. Health problems can arise because within a day or two of harvesting some crop nitrates are converted into nitrites which can react with the haemoglobin (especially fetal haemoglobin) to form methaemoglobin which cannot transport oxygen. An upper limit of 45–50 mg nitrate/L drinking water has been recommended for infants. Also used, together with nitrite, for curing meat (see meat, curing). See also nitrosamines.
331 nitric oxide (NO) Synthesised in most mammalian cells by the action of nitric oxide synthetase (EC 1.14.13.39) on arginine. It causes vasodilatation and inhibits platelet aggregation (and so has anticoagulant action), acting by cell surface receptors and intracellular guanylate cyclase (EC 4.6.1.2), leading to increased formation of cyclic GMP. Before it was identiﬁed, NO was known as the endothelium-derived relaxation factor. nitrites Found in many plant foods, since they are rapidly formed by the reduction of naturally occurring nitrate. Nitrite is the essential agent in preserving meat by pickling, since it inhibits the growth of Clostridia; it also combines with the myoglobin of meat to form the characteristic red nitrosomyoglobin. See also nitrosamines. nitrogen A gas comprising about 80% of the atmosphere; in nutrition the term ‘nitrogen’ is used to refer to ammonium salts and nitrates utilised as plant fertilisers; proteins and amino acids as animal nutrients; and urea and ammonium salts as excretory products. nitrogenase The enzyme (EC 1.18.6.1 or 1.19.6.1) in nitrogen- ﬁxing micro-organisms that catalyses the reduction of N2 to ammonia. Irreversibly inactivated by oxygen. See also leghaemoglobin. nitrogen balance (N balance) The difference between the dietary intake of nitrogen (mainly protein) and its excretion (as urea and other waste products). Healthy adults excrete the same amount as is ingested, and so are in nitrogen equilibrium. During growth and tissue repair (convalescence) the body is in positive N balance, i.e. ingestion is greater than loss and there is an increase in the total body pool of nitrogen (protein). In fevers, fasting and wasting diseases (see cachexia) the loss is greater than the intake and the individual is in negative balance; there is a net loss of nitrogen from the body. nitrogen conversion factor Factor by which total nitrogen content of a material (measured chemically, e.g. by the kjeldahl deter- mination) is multiplied to determine the protein; depends on the amino acid composition of the proteins concerned. Wheat and most cereals 5.8, rice 5.95, soya 5.7, most legumes and nuts 5.3, milk 6.38, other foods 6.25. Errors arise if part of the nitrogen is non-protein nitrogen. In mixtures of proteins, as in dishes and diets, the factor of 6.25 is used. Crude protein is deﬁned as N × 6.25. nitrogen equilibrium See nitrogen balance. nitrogen-free extract (NFE) In the analysis of foods and animal feedingstuffs, the fraction that contains the sugars and starches plus small amounts of other materials.
332 nitrogen, metabolic Nitrogen in the faeces derived from internal or endogenous sources, as distinct from nitrogen-containing dietary sources (exogenous nitrogen). This nitrogen consists of unabsorbed digestive juices, mucus, shed intestinal mucosal cells and intestinal bacteria, and continues to be excreted on a protein-free diet. nitrogen trichloride See agene. nitro-keg beer conditioned in kegs under nitrogen, to give a smoother, creamier beverage than traditional conditioning under carbon dioxide. nitrosamines N-Nitroso derivatives of amines. Found in trace amounts in mushrooms, fermented ﬁsh meal and smoked ﬁsh, and in pickled foods, where they are formed by reaction between nitrite and amines. They cause cancer in experimental animals, but it is not known whether the small amounts in foods affect human beings. They are also found in human gastric juice, possi- bly as a result of reaction between dietary amines and nitrites or nitrates. nitrosomyoglobin The red colour of cured meat, formed by the reaction of nitrite with myoglobin. Fades in light to yellow- brown metmyoglobin. nitrous oxide N2O, a gas used as a propellant in pressurised containers, e.g. to eject cream or salad dressing from containers. nivalenol Trichothecene mycotoxin produced when cereals are infected with Fusarium spp. nixtamal The paste produced by steeping maize in calcium hydroxide solution to make tortillas and tacos; the process is nixtamalisation. N-liteTM fat replacer made from starch. NMR Nuclear magnetic resonance. NO See nitric oxide. no adverse effect level (NAEL) Highest dose or intake of a com- pound at which no adverse effect can be detected. See also ld50; minimum lethal dose. noble rot White grapes affected by the fungus Botrytis cinerea. It spoils the grapes if they are damaged by rain, but if they are ripe and healthy, and the weather is sunny, it causes them to shrivel and concentrates the sugar, so that top-quality sweet wines can be made. See also wine classiﬁcation, germany. No Effect Level (NEL) With respect to food additives, the maximum dose of an additive that has no detectable adverse effects. See also acceptable daily intake.
333 noggin Traditional measure of liquor = /4 pint (140 mL); also 1 known as a quartern. N-oilTM fat replacer made from starch. nominal freezing time The time between the surface of the food reaching 0 °C and the thermal centre reaching 10 °C below the temperature of the ﬁrst ice formation. non-essential amino acids Those amino acids that can be synthesised in the body and therefore are not dietary essentials. non-esteriﬁed fatty acids (NEFA) See fatty acids, free. non-hygroscopic foods Foods that have a constant water vapour pressure at different moisture contents, and so do not take up moisture from the atmosphere. noni (Indian mulberry) Fruit of the south Paciﬁc evergreen shrub Morinda citrifolia, with an unpleasant odour; the juice is claimed to have healing properties and to be beneﬁcial in treatment of diabetes, heart disease and cancer. non-Newtonian ﬂuid See shear rate. non-nutritive sweeteners See sweeteners, intense. non-saponiﬁed The water-insoluble material remaining in a fat or oil after saponiﬁcation; mainly sterols, higher alcohols, hydro- carbons and pigments. non-starch polysaccharides (NSP) (see p. 334) Those polysac- charides (complex carbohydrates) found in foods other than starches. They are the major part of dietary ﬁbre (see ﬁbre, dietary) and can be measured more precisely than total dietary ﬁbre; include cellulose, pectins, glucans, gums, mucilages, inulin and chitin (and exclude lignin).The NSP in wheat, maize and rice are mainly insoluble and have a laxative effect, while those in oats, barley, rye and beans are mainly soluble and have a blood cholesterol-lowering effect. In vegetables the pro- portions of soluble to insoluble are roughly equal but vary in fruits. noodles pasta made with ﬂour from various grains (e.g. rice, wheat, buckwheat, mung bean starch) and water; may have egg added. nopales Stems or pads of the prickly pear cactus (Opuntia spp.). Composition/100 g: (edible portion 96%) water 94.1 g, 67 kJ (16 kcal), protein 1.3 g, fat 0.1 g, carbohydrate 3.3 g (1.1 g sugars), ﬁbre 2.2 g, ash 1.1 g, Ca 164 mg, Fe 0.6 mg, Mg 52 mg, P 16 mg, K 257 mg, Na 21 mg, Zn 0.3 mg, Cu 0.1 mg, Mn 0.5 mg, Se 0.7 µg, vitamin A 23 µg RE (298 µg carotenoids), K 5.3 mg, B1 0.01 mg, B2 0.04 mg, niacin 0.4 mg, B6 0.07 mg, folate 3 µg, pantothenate 0.2 mg, C 9 mg.
334 NON-STARCH POLYSACCHARIDES
335 nor- Chemical preﬁx to the name of a compound indicating: (1) One methyl (CH3) group has been replaced by hydrogen (e.g. noradrenaline can be considered to be a demethylated derivative of adrenaline). (2) A homologue of a compound containing one methylene (CH2) group fewer than the parent compound. (3) An isomer with an unbranched side-chain (e.g. norleucine, norvaline). noradrenaline Hormone secreted by the adrenal medulla together with adrenaline; also a neurotransmitter. Physio- logical effects similar to those of adrenaline. Also known as norepinephrine. norconidendrin See conidendrin. nordihydroguaiaretic acid (NDGA) Extracted from the creosote bush, Larrea divaricata (Covillea tridentata); used as an antioxi- dant for fats. norepinephrine See noradrenaline. nori Edible seaweed, Porphyra umbilicalis. norite Activated charcoal used to decolourise solutions. norleucine 2-Aminohexanoic acid, a non-physiological amino acid, an unbranched isomer of leucine, commonly used as an internal standard in amino acid analysis. northern blot See blotting. notatin See glucose oxidase. nougat Sweetmeat made from a mixture of gelatine or egg albumin with sugar and starch syrup, and the whole thoroughly aerated. Originated in Montelimar in southern France. NovadeloxTM Benzoyl peroxide used for treating ﬂour, see ageing. novain Obsolete name for carnitine. novel foods Foods and food ingredients consisting of, or contain- ing, chemical substances not hitherto used for human consump- tion to a signiﬁcant extent in the locality in question (including micro-organisms, fungi or algae and substances isolated from them, and organisms obtained using genetic modiﬁcation tech- niques).A food or ingredient to which has been applied a process not currently used for food manufacture or which has not been previously marketed and which gives rise to changes that affect its nutritional value or safety. See also substantial equivalence. NoveloseTM A preparation of resistant starch. See starch, resistant. NPR Net protein ratio, a measure of protein quality. NPU Net protein utilisation, a measure of protein quality. NPV Net protein value, a measure of protein quality.
336 NSP See non-starch polysaccharides. nubbing Term used in the canning industry for ‘topping and tailing’ of gooseberries. nucellar layer Of wheat, the layer of cells that surrounds the endosperm and protects it from the entry of moisture. nucleation The formation of a nucleus of water molecules that is required for ice crystal formation. nucleic acids Polymers of purine and pyrimidine sugar phos- phates; two main classes: ribonucleic acid (RNA) and deoxyri- bonucleic acid (DNA). Collectively the purines and pyrimidines are called bases. DNA is a double-stranded polymer (the so- called ‘double helix’) containing the ﬁve-carbon sugar deoxyri- bose. RNA is a single-stranded polymer containing the sugar ribose. Not nutritionally important, since dietary nucleic acids are hydrolysed to their bases, ribose and phosphate in the intestinal tract; purines and pyrimidines can readily be synthesised in the body, and are not dietary essentials. nucleoproteins The complex of proteins and nucleic acids found in the cell nucleus. nucleosides Compounds of purine or pyrimidine bases with a sugar, most commonly ribose. For example, adenine plus ribose forms adenosine. With the addition of phosphate a nucleotide is formed. nucleotides Compounds of purine or pyrimidine base with a sugar phosphate; the monomer units of DNA and RNA. Natural constituents of human milk, often used to supplement infant formulae. nug See nigerseed. nuoc mam Vietnamese, Cambodian; fermented ﬁsh sauce. The ﬁsh is digested by autolytic enzymes in the presence of salt added to inhibit bacterial growth. nutmeg Dried ripe seed of Myristica fragrans; mace is the seed coat (arillus). Both mace and nutmeg are used as ﬂavourings in meat products and bakery goods. nutraceuticals Term for compounds in foods that are not nutri- ents but have (potential) beneﬁcial effects. See also functional foods. NutrasweetTM See aspartame. nutricines Biologically active ingredients in animal feedstuff used to promote nutrition-based health. nutrient density A way of expressing the nutrient content of a food or diet relative to the energy yield (i.e. per 1000 kcal or per MJ) rather than per unit weight.
337 nutrient enemata See rectal feeding. See also enteral nutrition; parenteral nutrition. nutrients Essential dietary factors such as vitamins, minerals, amino acids and fatty acids. Metabolic fuels (sources of energy) are not termed nutrients so that a commonly used phrase is ‘energy and nutrients’. nutriﬁcation The addition of nutrients to foods at such a level as to make a major contribution to the diet. nutrigenetics The study of the effects of genotype on nutrient requirements and effects of diet on health. See also nutrigenomics. nutrigenomics The study of how nutrients interact with the genome, and identiﬁcation of nutrient-sensitive genes. See also nutrigenetics. nutrition The process by which living organisms take in and use food for the maintenance of life, growth, the functioning of organs and tissues and the production of energy; the branch of science that involves these processes. See also enteral nutrition; parenteral nutrition; rectal feeding. nutritional claim Any representation that states, suggests or implies that a food has particular nutrition-related health prop- erties. The extent of such claims on food labelling (see nutri- tional labelling) and advertising are controlled by law in most countries. nutritional disorder Any morbid process or functional abnor- mality of the body due to the consumption of a diet not con- forming to physiological requirements, or to failure in absorption or utilisation of the food after ingestion. nutritional genomics General term to include both nutrigenet- ics and nutrigenomics. nutritional labelling Any information appearing on labelling or packaging of foods relating to energy and nutrients in the food. Voluntary in the EU; if nutritional information is given, it must be in a standard format. The information must be given /100 g (or /100 mL), and may also, optionally, be given per serving of a stated size. In the USA nutritional labelling is obligatory, and information must be given in a standard format per serving (as deﬁned by the Food and Drug Administration), and may option- ally be given /100 g or /100 mL. nutritional recommendations Recommendations comprising nutri- ent goals, food goals and dietary guidelines. In addition to ref- erence intakes of nutrients, key recommendations in developed countries are reduction of total fat intake to 30% of energy
338 intake, with a more severe restriction of saturated fats (see fat, saturated) (to 10% of energy intake); increase of carbohydrate intake to 55% of energy intake (with a reduction of sugars to 10% of energy intake); increased intake of non-starch polysac- charides and reduced intake of salt. nutritional status assessment In adults, general adequacy of nutri- tion is assessed by measuring weight and height; the result is commonly expressed as the body mass index, the ratio of weight (kg)/height2 (m). Body fat may also be estimated, by measuring skinfold thickness, and muscle diameter is also measured. For children, weight and height for age are compared with standard data for adequately nourished children. The increase in the cir- cumference of the head and the development of bones may also be measured. Status with respect to individual vitamins and min- erals is normally determined by laboratory tests, either measur- ing the blood and urine concentrations of the nutrients and their metabolites, or by testing for speciﬁc metabolic responses. See also anthropometry; enzyme activation assays. nutritionist One who applies the science of nutrition to the pro- motion of health and control of disease; instructs auxiliary medical personnel; participates in surveys. Not legally deﬁned in the UK, but there is a Register of Accredited Nutritionists main- tained by the Nutrition Society. See also dietitian. nutrition policy (or planning) A set of concerted actions, based on a governmental mandate, intended to ensure good health of the population through informed access to safe, healthy and ade- quate food. nutrition surveillance Monitoring the state of health, nutrition, eating behaviour and nutrition knowledge of a given population for the purpose of planning and evaluating nutrition policy. Especially in developing countries, monitoring may include factors that may be potential causes of nutritional emergencies, in order to give early warning of such emergencies. nutritive ratio In animal feeding; a measure of the value of a feed- stuff for growth (or milk production) compared with its fatten- ing value. It is the sum of the digestible carbohydrate, protein and 2.3 × fat, divided by digestible protein. Ratio 4–5 for growth, 7–8 for fattening. nutritive value index In animal feeding; intake of digestible energy expressed as energy digestibility multiplied by voluntary intake of dry matter of a particular feed, divided by metabolic weight (weight0.75), compared with standard feed. nutro-biscuit Indian; biscuit baked from a mixture of 60% wheat ﬂour and 40% peanut ﬂour; contains 16–17% protein.
339 nutro-macaroni Indian; mixture of 80 parts wheat ﬂour, 20 parts defatted peanut meal (19% protein). nuts Hard-shelled fruit of a wide variety of trees, e.g. almonds, brazil, cashew, peanut, walnut. All have high fat content, 45–60%; high protein content, 15–20%; 15–20% carbohydrate. The chestnut is an exception, with 3% fat and 3% protein, being largely carbohydrate, 37%. A number of nuts are grown mainly for their oils; see oilseed. NVDP Non-volatile decomposition products. nyctalopia See night blindness. nystagmus Rapid involuntary movement of the eyes, as when fol- lowing a moving object; may also occur as a result of a congen- ital defect, and in the wernicke–korsakoff syndrome due to vitamin b1 deﬁciency. O OatrimTM fat replacer made from non-starch polysaccharide. oats Grain from Avena spp., especially A. sativa, A. steritis and A. strigosa. Oatmeal, ground oats; oatﬂour, ground and bran removed; groats, husked oats; Embden groats, crushed groats; Scotch oats, groats cut into granules of various sizes; Sussex ground oats, very ﬁnely ground oats; rolled oats, crushed by rollers and partially precooked. Composition /100 g: water 8 g, 1628 kJ (389 kcal), protein 16.9 g, fat 6.9 g (of which 20% saturated, 37% mono-unsaturated, 42% polyunsaturated), carbohydrate 66.3 g, ﬁbre 10.6 g, ash 1.7 g, Ca 54 mg, Fe 4.7 mg, Mg 177 mg, P 523 mg, K 429 mg, Na 2 mg, Zn 4 mg, Cu 0.6 mg, Mn 4.9 mg, vitamin E 1.1 mg, B1 0.76 mg, B2 0.14 mg, niacin 1 mg, B6 0.12 mg, folate 56 µg, pantothenate 1.3 mg. A 30 g serving is a source of Cu, Mg, P, vitamin B1, a rich source of Mn. obesity Excessive accumulation of body fat. A body mass index (BMI) above 30 kg/m2 is considered to be obesity (and above 40 gross obesity). The desirable range of BMI for optimum life expectancy is 20–25; between 25 and 30 is considered to be overweight rather than obesity. People more than 50% above desirable weight are twice as likely to die prematurely as those within the desirable weight range. obesity, dietary Obesity in experimental animals induced by over- feeding, as opposed to pharmacological treatment or as a result of genetic defects. ob-ob mouse A genetically obese mouse; the defective gene was cloned in 1994, and the gene product was identiﬁed as leptin.