The Protein Amino Acids

is not an essential amino acid, it can only be synthesised from methionine, and it is conventional to consider the sum of methionine + cysteine in determinations of protein quality. aminoaciduria Excretion of abnormally large amounts of an amino acid or a group of metabolically related amino acids. Overflow aminoaciduria occurs when the plasma concentration exceeds the renal threshold, as a result of impaired metabolism; renal aminoaciduria occurs with normal or lower than normal plasma concentrations, as a result of impaired renal resorption of a group of amino acids that share a common transport system. In either case aminoaciduria may be due to a genetic defect or acquired (i.e. secondary to toxicity or disease). aminoacylase Enzyme (EC which catalyses esterifica-tion specifically of D-amino acids; used in resolution of racemic mixtures of amino acids resulting from chemical synthesis. aminogram A diagrammatic representation of the amino acids in a protein or peptide. A plasma aminogram represents the amounts of free amino acids in blood plasma. amino group The —NH2 group of amino acids and amines. aminopeptidase Enzyme (EC secreted in the intestinal juice which removes amino acids sequentially from the free amino terminal of a peptide or protein, i.e. an exopeptidase. aminopterin Aminopteroylglutamic acid; metabolic antagonist

(antivitamin) of folic acid. aminosalicylates 5-Aminosalicylate and its derivatives (bal-salazide, mesalazine, olsalazine, sulphasalazine) used in treatment of ulcerative colitis. aminotransferase See transaminase.

amla Indian gooseberry, Emblica officinalis Gaertn., important in Ayurvedic medicine and reported to reduce hypercholestero-laemia. An extremely rich source of vitamin C (600mg/100g). amoebiasis (amoebic dysentery) Infection of the intestinal tract with pathogenic amoeba (commonly Entamoeba histolytica) from contaminated food or water, causing profuse diarrhoea, intestinal bleeding, pain, jaundice, anorexia and weight loss. amomum A group of tropical plants including cardamom and melegueta pepper, which have pungent and aromatic seeds. AMP Adenosine monophosphate, see adenine. amphetamine A chemical at one time used as an appetite suppressant, addictive and a common drug of abuse ('speed'), its use is strictly controlled by law. Also known as benzedrine. amphoteric See isoelectric point.

amulum Roman; starch used to thicken sauces, made by soaking wheat grains in water, then straining the liquid and pouring onto a tiled floor to thicken in the sun.

amydon A traditional starchy material made by steeping wheat flour in water, then drying the starch sediment in the sun, used for thickening broths, etc. amygdalin (1) A glycoside in almonds and apricot and cherry stones which is hydrolysed by the enzyme emulsin to yield glucose, cyanide and benzaldehyde. It is therefore highly poisonous, although it has been promoted, with no evidence, as a nutrient, laetrile or so-called vitamin B17. Unfounded claims have been made for its value in treating cancer.

(2) French name for cakes and sweets made with almonds. amylases Enzymes that hydrolyse starch. a-Amylase (dex-trinogenic amylase or diastase, EC acts randomly on a-1,4-glucoside bonds in the molecule, and produces small dextrin fragments. P-Amylase (maltogenic or glucoamylase, EC acts at the non-reducing end of the molecule to liberate maltose plus some free glucose, and isomaltose from the branch points in amylopectin. Salivary amylase (sometimes called by its obsolete name of ptyalin) and pancreatic amylase are both a-amylases.

Major sources of a-amylase in the baking and brewing industries are Aspergillus oryzae (fungal amylase) and Bacillus sub-tilis, in addition to malted (sprouted) cereals added to increase the hydrolysis of starch to fermentable sugars.

See also debranching enzymes; diastatic activity; z-enzyme. amyli Dried tamarind.

amylin A peptide that is secreted together with insulin from the pancreatic p-islet cells during and after food intake; it has a potent anorectic (appetite suppressant) action. amylo-amylose Obsolete name for amylose. amylodyspepsia An inability to digest starch. amyloglucosidase See debranching enzymes. amylograph A device to measure the viscosity of flour paste as it is heated from 25 °C to 90°C (as occurs in baking), which serves as a measure of the diastatic activity of the flour. amyloins Carbohydrates that are complexes of dextrins with varying proportions of maltose. amylopectin The branched chain form of starch, about 75% of the total, the remainder being straight chain amylose. Consists of chains of glucose units linked a-1,4, with 5% of the glucose linked a-1,6 at branch points; gives purplish colour with iodine. amylopeptic A general term for enzymes that are able to hydrolyse starch to soluble products. amyloplasts Organelles in the endosperm of cereal grains in which starch granules are synthesised. amylopsin Alternative name for pancreatic amylase.

amylose The straight chain form of starch, ~25% of the total, consisting of glucose units linked a-1,4; gives blue colour with iodine.

See also amylopectin. anabiosis Suspended animation with stoppage of respiration and heart beat caused by freeze drying, e.g. of insects during cold spells.

anabolic agents Those hormones (and hormone-like drugs) that stimulate growth and the development of muscle tissue. anabolism The process of building up or synthesising, see metabolism.

anaemia Shortage of haemoglobin in blood (less than 85% of the reference range; <130g/L in adult men, or <120g/L in women) leading to chronic pallor and shortness of breath on exertion. Most commonly due to dietary deficiency of iron or chronic blood loss resulting in a reduced number of smaller red blood cells (microcytic) which also include less haemoglobin (hypochromic anaemia).

Other dietary deficiencies can lead to anaemia: vitamin b6 deficiency impairs haemoglobin synthesis; vitamin c deficiency impairs iron absorption; folic acid and vitamin b12 deficiencies result in megaloblastic anaemia, the release of immature precursors of red blood cells into the circulation. anaemia, haemolytic anaemia caused by premature and excessive destruction of red blood cells, commonly in response to a toxic stress (see favism). Rarely due to nutritional deficiency, but may be a result of vitamin E deficiency in premature infants. Measurement of haemolysis in vitro, induced by dialuronic acid or hydrogen peroxide, provides an index of vitamin e status. anaemia, megaloblastic Release into the circulation of immature precursors of red blood cells, due to deficiency of either folic acid or vitamin b12.

See also anaemia, pernicious; figlu test; dump suppression test; schilling test. anaemia, pernicious anaemia due to deficiency of vitamin b12, most commonly as a result of failure to absorb the vitamin from the diet. There is release into the circulation of immature precursors of red blood cells, the same type of megaloblastic anaemia as is seen in folic acid deficiency. There is also progressive irreversible damage to the spinal cord (sub-acute combined degeneration). The underlying cause of the condition may be the production of antibodies against either the intrinsic factor that is required for absorption of the vitamin, or the cells of the gastric mucosa that secrete intrinsic factor. Atrophy of the gastric mucosa with ageing also impairs vitamin B12 absorption, and causes pernicious anaemia. Dietary deficiency of vitamin B12 may occur in strict vegetarians (vegans).

See also dump suppression test; intrinsic factor; schilling test.

anaerobes See aerobic.

anaerobic threshold The level of exercise at which the rate of oxygen uptake into muscle becomes limiting and there is an increasing proportion of anaerobic glycolysis to yield lactate.

See also aerobic (2). analysis, gastric See fractional test meal. analysis, proximate See proximate analysis. analyte A compound that is analysed or assayed. ananas See pineapple.

anaphylactic (anaphylaxic) shock Abnormally severe allergic reaction to an antigen in which histamine is released from mast cells, causing widespread symptoms. anatto See annatto.

anchovy Small oily fish, Engraulis spp., usually semipreserved with 10-12% salt and sometimes benzoic acid.

Composition (fresh)/100g: water 73 g, 548kJ (131kcal), protein 20g, fat 4.8g (of which 31% saturated, 29% mono-unsaturated, 49% polyunsaturated), cholesterol 60 mg, ash 1.4g, Ca 147mg,Fe 3.3mg, Mg 41mg, P 174mg, K 383mg, Na 104mg, Zn 1.7mg, Cu 0.2mg, Se 36.5 |g, vitamin A 15 |g retinol, E 0.6 mg, K 0.1 mg, B1 0.06 mg, B2 0.26 mg, niacin 14 mg, B6 0.14 mg, folate 9 |g, B12 0.6 |g, pantothenate 0.6mg.

Anchovy butter is prepared from pounded fillets of anchovy mixed with butter as a savoury spread; anchovy paste from pounded fillets of anchovy mixed with vinegar and spices. ancyclostomiasis Infestation with hookworm. androgens Male sex hormones (steroids), testosterone, dihy-drotestosterone and androsterone. Sometimes used as anabolic agents.

aneurine Obsolete name for vitamin b1.

aneurysm Local dilatation (swelling and weakening) of the wall of a blood vessel, usually the result of atherosclerosis and hypertension; especially serious in the aorta, where rupture may prove fatal.

angelica Crystallised young stalks of the umbelliferous herb Angelica archangelica, which grows in southern Europe. They are bright green in colour, and are used to decorate and flavour confectionery goods. The roots are used together with juniper berries to flavour gin, and the seeds are used in vermouth and chartreuse. essential oils are distilled from the root, stem and leaves.

angels on horseback Shelled oysters wrapped in bacon, skewered on a toothpick and then grilled.

See also devils on horseback. angina (angina pectoris) Paroxysmal thoracic pain and choking sensation, especially during exercise or stress, due to partial blockage of the coronary artery (the blood vessel supplying the heart), as a result of atherosclerosis. angiotensin Peptide hormone formed in the circulation by the action of renin (EC on a-globulin; converted to the active vasoconstrictor angiotensin II by angiotensin converting enzyme (ace, EC in the lungs. Angiotensin II also stimulates secretion of aldosterone and vasopressin, so increasing blood pressure. angiotensinogenase See renin.

Angostura The best known of the bitters, widely used in cocktails; a secret blend of herbs and spices, including the bitter aromatic bark of either of two trees of the orange family (Galipea officinalis, Cusparia felorifuga). Invented in 1818 by Dr Siegert in the town of Angostura in Venezuela (now called Ciudad Bolivar), originally as a medicine, and now made in Trinidad. A few drops of Angostura in gin makes a 'pink gin'. angstrom A unit of length equal to 10-8cm (10-10m) and hence = 10 nm; not an official SI unit, but commonly used in structural chemistry and crystallography. angular stomatitis A characteristic cracking and fissuring of the skin at the angles of the mouth, a symptom of vitamin b2 deficiency, but also seen in other conditions. anhydrovitamin A Isomer of retinol in which the —OH group has been removed by treatment with hydrochloric acid, with corresponding shift in the double bonds. Once incorrectly called cyclised or spurious vitamin a, it has very slight biological activity. animal charcoal See bone charcoal.

animal protein factor A name given to a growth factor or factors which were found to be present in animal but not vegetable proteins, one of which was identified as vitamin b12. anion A negatively charged ion.

aniseed (anise) The dried fruit of Pimpinella anisum, a member of the parsley family, which is used to flavour baked goods, meat dishes and drinks, including anise, anisette and ouzo. Chief component of the volatile oil is anethole (methoxypropenyl benzene).

See also anise, star. anise pepper A pungent spice from the Sichuan region of China (the fruit of Zanthoxylum piperitum); the flavour develops gradually after biting into the pepper.

anise, star A spice, the seeds of Illicium verum, widely used in

Chinese cooking. Distinct from aniseed. annatto (anatto) Also known as bixin, butter colour or rocou; a yellow colouring (E-160b) extracted from the pericarp of the fruit of the tropical shrub Bixa orellana. The main component is the carotenoid bixin, which is fat-soluble. It is used to colour cheese, dairy produce and baked goods. The seeds are used for flavouring in Caribbean foods. annealing Heating to control the ductility of a material. anomers A pair of stereo-isoMERS related in the same way as a-

and P-glucose are related to one another. anona See custard apple.

anorectic drugs (anorexigenic drugs) Drugs that depress the appetite, used as an aid to weight reduction. Diethylpropion, fenfluramine (and dexfenfluramine),phenmetrazine hydrochloride and mazindol have been used, but are no longer recommended. amphetamines were used at one time, but are addictive and subject to special control. anorexia Lack of appetite.

anorexia nervosa A psychological disturbance resulting in a refusal to eat, possibly with restriction to a very limited range of foods, and often accompanied by a rigid programme of vigorous physical exercise, to the point of exhaustion. Anorectic subjects generally do not feel sensations of hunger. The result is a very considerable loss of weight, with tissue atrophy and a fall in basal metabolic rate. It is especially prevalent among adolescent girls; when body weight falls below about 45 kg there is a cessation of menstruation as a result of low secretion of leptin from the low reserves of adipose tissue.

See also bulimia nervosa. anosmia Lack or impairment of the sense of smell. anserine A dipeptide of P-alanine and 3-methylhistidine found in muscle, of unknown function. Antabuse™ The drug disulfiram (tetraethyl thiuramdisulphide), used in the treatment of alcoholism. It inhibits the further metabolism of acetaldehyde arising from the metabolism of alcohol, and so causes headache, nausea, vomiting and palpitations if alcohol is consumed. antacids Alkalis or buffers that neutralise acids, used generally to counteract excessive gastric acidity and treat indigestion. Antacid preparations generally contain such compounds as sodium bicarbonate, aluminium hydroxide, magnesium carbonate or magnesium hydroxide. anthelmintic Drugs used to treat infestation with parasitic worms (helminths).

See also flukes; hookworm; tapeworm.

anthocyanidins The aglycones of anthocyanins. anthocyanins Violet, red and blue water-soluble pigments in many flowers, fruits and leaves, used in food colours (E-163). Relatively stable to heat, light and oxygen. They can react with iron or tin, giving rise to discoloration in canned foods. anthoxanthins Alternative name for flavonoids. anthrone method See clegg anthrone method. anthropometry Measurement of the physical dimensions and gross composition of the body as an index of development and nutritional status; a non-invasive way of assessing body composition.

Weight-for-age provides information about the overall nutritional status of children; weight-for-height is used to detect acute malnutrition (wasting); height-for-age to detect chronic malnutrition (stunting). Mid-upper arm circumference provides an index of muscle wastage in undernutrition.

skinfold thickness is related to the amount of subcutaneous fat as an index of over- or undernutrition.

Head circumference for age provides an index of chronic undernutrition during intrauterine development or the first two years of life.

See also body composition; body mass index; cristal height; knee height; stunting; tuxford's index; wetzel grid. antibiotics Substances produced by living organisms that inhibit the growth of other organisms. The first antibiotic to be discovered was penicillin, which is produced by the mould Penicillium notatum and inhibits the growth of sensitive bacteria. Many antibiotics are used to treat bacterial infections in human beings and animals; different compounds affect different bacteria.

Small amounts of antibiotics may be added to animal feed (a few grams per tonne), resulting in improved growth, possibly by controlling mild infections or changing the population of intestinal bacteria and so altering the digestion and absorption of food. To prevent the development of antibiotic-resistant strains of disease-causing bacteria, only those antibiotics that are not used clinically are permitted in animal feed (e.g. nisin, which is also used as a food preservative (E-234)).

See also tetracyclines. antibodies A class of proteins formed in the body in response to the presence of antigens (foreign proteins and other compounds), which bind to the antigen, so inactivating it. Immunity to infection is due to the production of antibodies against specific proteins of bacteria, viruses or other disease-causing organisms, and immunisation is the process of giving these marker proteins, generally in an inactivated form, to stimulate the production of antibodies. adverse reactions to foods (food aller gies) may be due to the production of antibodies against specific food proteins. Chemically the antibodies form a class of proteins known as the y-globulins or immunoglobulins; there are five types, classified as IgA, IgD, IgE, IgG and IgM.

A monoclonal antibody consists of a single protein species. They are produced by fusing sensitised B-lymphocytes from the spleen of an animal immunised with the antigen with myeloma cells, in vitro. The hybrid cells are selected by use of appropriate culture media, diluted so that individual colonies can be raised from a single cell, and therefore produce a single antibody. Theoretically permits very much more specific immunoassay than mixed antisera raised in vivo, which are polyclonal antibodies. anticaking agents Substances added in small amounts to powdered foodstuffs such as salt, icing sugar and baking powder to prevent caking, e.g. polyphosphates (E-544, 545), aluminium calcium silicate (E-556), calcium silicate (E-552), magnesium carbonate (E-504), calcium carbonate (E-170). anticoagulants Compounds that prevent or slow the process of blood clotting or coagulation, either in samples of blood taken for analysis or in the body. One of the most commonly used is heparin, which is formed in the lungs and liver. People at risk of thrombosis are often treated with warfarin and similar compounds as an anticoagulant, to reduce the risk of intravenous blood clotting. These act as antagonists of vitamin k in the synthesis of blood clotting proteins. Oxalate and citrate function as anticoagulants in vitro because they remove calcium from the blood clotting system; hirudin (from leeches) inactivates prothrombin.

See also blood clotting. antidiarrhoeal agents Two groups of compounds are used to treat diarrhoea: adsorbants such as attapulgite (hydrated aluminium magnesium silicate) and kaolin (hydrated aluminium silicate), and compounds that decrease intestinal motility, such as codeine, diphenoxylate and loperamide.

See also antimotility agents. antidiuretic Drug used to reduce the excretion of urine and so conserve fluid in the body.

See also water balance. antidiuretic hormone (ADH) See vasopressin. antiemetics A variety of compounds used to treat persistent vomiting, including dopamine, serotonin and muscarinic cholinergic antagonists, antihistamines, cannabinoids, corticosteroids and some of the neuroleptic agents. antienzymes Substances that specifically inhibit the action of enzymes. Many specifically inhibit digestive enzymes and are present in raw legumes (antitrypsin and antiamylase), anticholinesterase (solanine), anti-invertase. Most are proteins and are therefore inactivated by heat. Many intestinal parasites are protected by antienzymes. antifoaming agents Octanol, sulphonated oils, silicones, etc. used to reduce foaming caused by the presence of dissolved protein. antigalactic Drug that reduces or prevents the secretion of milk in women after parturition. antigen Any compound that is foreign to the body (e.g. bacterial, food or pollen protein, or some complex carbohydrates) which, when introduced into the circulation, stimulates the formation of an antibody.

See also adverse reactions to foods. anti-grey hair factor Deficiency of the vitamin pantothenic acid causes loss of hair colour in black and brown rats, and at one time the vitamin was known as the anti-grey hair factor. It is not related to the loss of hair pigment in human beings. antihaemorrhagic vitamin See vitamin k. antihistamine Drug that antagonises the actions of histamine; those that block histamine H1 receptors are used to treat allergic reactions; those that block H2 receptors are used to treat peptic ulcers.

antihypertensive Drug, diet or other treatment used to treat hypertension by lowering blood pressure. antilipidaemic Drug, diet or other treatment used to treat hyper-

lipidaemia by lowering blood lipids. antimetabolite Compound that inhibits a normal metabolic process, acting as an analogue of a normal metabolite. Some are useful in chemotherapy of cancer, others are naturally occurring toxins in foods, frequently causing vitamin deficiency diseases by inhibiting the normal metabolism of the vitamin.

See also antivitamins. antimicrobial agents Compounds used to preserve food by preventing growth of micro-organisms (bacteria and fungi). antimony Toxic metal of no known metabolic function, so not a dietary essential. Antimony compounds are used in treatment of some parasitic diseases. antimotility agents Drugs used to reduce gastrointestinal motility, and hence reduce the discomfort associated with diarrhoea: codeine phosphate, co-phenotrope (diphenoxylate plus atropine sulphate), loperamide, morphine. antimutagen Compound acting on cells and tissues to decrease initiation of mutation by a mutagen. antimycotics (antimould agents) Substances that inhibit the growth of moulds and fungi. Sorbates (E-200-203), benzoates

(E-210-213), propionates (E-280-283), hydroxybenzoates (E-214-219) are used in foods. antineuritic vitamin Obsolete name for vitamin b1. antioxidant (1) A substance that retards the oxidative rancidity of fats in stored foods. Many fats, and especially vegetable oils, contain naturally occurring antioxidants, including vitamin e (E-306-309), which protect them against rancidity for some time. Synthetic antioxidants include propyl, octyl and dodecyl gallates (E-310-312), butylated hydroxyanisole (BHA, E-320) and buty-lated hydroxytoluene (BHT, E-321).

See also induction period.

(2) Highly reactive oxygen radicals are formed both during normal oxidative metabolism and in response to infection, radiation and some chemicals. They cause damage to fatty acids in cell membranes, and the products of this damage can then cause damage to proteins and dna. The most widely accepted theory of the biochemical basis of much cancer, and also of atherosclerosis and possibly kwashiorkor, is that the key factor in precipitating the condition is tissue damage by radicals.

A number of different mechanisms are involved in protection against, or repair after, oxygen radical damage, involving a number of nutrients, especially vitamin e, carotene, vitamin c and selenium. Collectively these are known as antioxidant nutrients.

antiracchitic Preventing or curing rickets. antiscorbutic Preventing or curing scurvy. vitamin c was originally known as the antiscorbutic vitamin. antisialagogues Substances that reduce the flow of saliva. antispasmodic Drugs that relieve spasm of smooth muscle (e.g.

intestinal muscle). antispattering agents Compounds such as lecithin (E-322), sucrose esters of fatty acids (E-473) and esters of mono- and diglycerides (E-472) which are added to frying oils and fats to prevent potentially dangerous spattering. They function by preventing the coalescence of water droplets. antistaling agents Substances that soften the crumb and retard staling of baked products; e.g. sucrose stearate (E-473), poly-oxyethylene monostearate (E-430, 431), glyceryl monostearate (E-472), stearoyl tartrate (E-483). antivitamins Substances that interfere with the normal metabolism or function of vitamins, or destroy them. Dicoumarol in spoiled sweet clover inhibits the metabolism of vitamin k, thi-aminase in raw fish hydrolyses vitamin b1, the drug methotrex-ate antagonises folic acid action (this is part of its mechanism of action in treating cancer), the drug isoniazid forms an inactive adduct with vitamin b6. antixerophthalmic vitamin See vitamin a. antral chalone Peptide hormone secreted by the stomach;

decreases gastric secretion. antralectomy Surgical removal of the antrum of the stomach, for treatment of peptic ulcers that are resistant to other therapy.

antrum The region of the stomach adjacent to the pylorus; it secretes most of the gastric acid, pepsin and gastrin. See gastrointestinal tract. AOAC International Originally the Association of Official Agricultural Chemists, formed in 1884 to adopt uniform methods of analysis of fertilisers; name changed in 1965 to the Association of Official Analytical Chemists. Its main purpose is to promote validation and quality assurance in analytical science, and to develop new methods. Web site AOM See active oxygen method. aortic aneurysm See aneurysm.

apastia Refusal to take food, as an expression of a psychiatric disturbance.

See also anorexia nervosa. aperient Any mild laxative. APF See animal protein factor.

APHA American Public Health Association; web site aphagia Inability to swallow. Difficulty in swallowing is dysphagia. aphagosis Inability to eat.

aphtha Small ulcers occurring singly or in groups in the mouth as small red or white spots. Cause unknown. apiculture Bee keeping for honey production; derives from the

Latin name of the honey bee, Apis mellifera. apio Root vegetable from the legume Apios tuberosa, eaten like potatoes. apo-carotenals See carotenals.

apoenzyme The protein part of an enzyme which requires a coenzyme for activity, and is therefore inactive if the coenzyme is absent.

See also enzyme activation assays; prosthetic group. apoferritin The protein part of ferritin. See iron storage. apolipoprotein The protein part of lipoproteins, without the associated lipid. See lipoproteins, plasma. Apollinaris water An alkaline, highly aerated, mineral water (see water, mineral) containing sodium chloride and calcium, sodium and magnesium carbonates, from a spring in the valley of Ahr (in Germany). apoptosis The process of programmed or organised cell death, as opposed to necrosis. aporrhegma Any of the toxic substances formed from amino acids during the bacterial decomposition of a protein. aposia Absence of sensation of thirst. apositia Aversion to food.

appendix (vermiform appendix) A residual part of the intestinal tract, a small sac-like process extending from the caecum, some 4-8 cm long. Acute inflammation, caused by an obstruction (appendicitis) can lead to perforation and peritonitis if surgery is not performed in time.

See also gastrointestinal tract. appenzeller Swiss hard cheese, washed with white wine and herbs while maturing.

appertisation French term for the process of destroying all the micro-organisms of significance in food, i.e. 'commercial sterility'; a few organisms remain alive but quiescent. Named after Nicholas Appert (1752-1841), a Paris confectioner who invented the process of canning, and opened the first vacuum bottling factory in 1804. appestat See appetite control.

appetite control Hunger centres found in the lateral hypothalamus initiate feeding; satiety centres found in the ventromedial hypothalamus signal satiety. Centres found in the temporal lobe (amygdala) control learnt food behaviour.

See also leptin.

apple Fruit of the tree Malus sylvestris and its many cultivars and hybrids; there are more than 2000 varieties in the British National Fruit Collection. Crab apples are grown mainly for decoration and for pollination of fruit-bearing trees, although the sour fruit can be used for making jelly. Cooking apples are generally sourer varieties than dessert apples and normally have flesh which crumbles on cooking; cider apples are sour varieties especially suited to the making of cider.

Composition/100g: (edible portion 92%) water 86g, 218kJ (52kcal), protein 0.3g, fat 0.2g, carbohydrate 13.8g (10.4g sugars), fibre 2.4g, ash 0.2g, Ca 6mg, Fe 0.1 mg, Mg 5mg, P 11 mg, K 107 mg, Na 1 mg, vitamin A 3 |g RE (67 |g carotenoids), E 0.2 mg, K 2.2 mg, B1 0.02mg, B2 0.03 mg, niacin 0.1 mg, B6 0.04 mg, folate 3 |g, pantothenate 0.1mg, C 5mg. apple brandy spirit made by distillation of cider, known in France as calvados.

See also apple jack.

apple butter Apple that has been boiled in an open pan to a thick consistency; similar to apple sauce, but darker in colour owing to the prolonged boiling. apple jack American name for apple brandy, normally distilled, but traditionally prepared by leaving cider outside in winter, when the water froze out as ice crystals, leaving the alcoholic spirit. apple nuggets Crisp granules of apple of low moisture content, used commercially for manufacture of apple sauce. apple-pear Not a cross between apple and pear but a distinctive type of pear-shaped fruit with apple texture. Also called Japanese pear, pear-apple, and shalea or chalea. apricot Fruit of the tree Prunus armeniaca.

Composition/100g: (edible portion 93%) water 86.3 g, 201 kJ (48 kcal), protein 1.4g, fat 0.4g, carbohydrate 11.1 g (9.2g sugars), fibre 2g, ash 0.8g, Ca 13mg, Fe 0.4mg, Mg 10mg, P 23mg, K 259 mg, Na 1mg, Zn 0.2 mg, Cu 0.1 mg, Mn 0.1 mg, Se 0.1 |jg, vitamin A 96|j.g RE (1306|j.g carotenoids), E 0.9mg, K 3.3 mg, B1 0.03 mg, B2 0.04 mg, niacin 0.6 mg, B6 0.05 mg, folate 9 |jg, pantothenate 0.2mg, C 10mg.

Apricot kernels are used to prepare almond oil; apricot kernel oil is 7% saturated, 63% mono-unsaturated, 31% polyunsaturated, vitamin E 4mg/100g. AQL Acceptable quality limit.

aquaculture The farming of aquatic organisms, including fish, molluscs, crustaceans, echinoderms (sea urchins), cephalopods (octopus, squid, cuttlefish), reptiles (alligators, sea turtles, freshwater turtles), amphibians (frogs) and aquatic plants. Includes fresh, salt and brackish water cultivation. aquamiel See pulque.

aquavit (akvavit or akavit) Scandinavian; spirit flavoured with herbs (commonly caraway, cumin, dill or fennel). Also known as snaps, and in Germany as schnapps. aquocobalamin See vitamin b12.

arabinogalactan Gum extracted from sap of larch trees (Larix spp.), also known as larch gum. araboascorbic acid See erythorbic acid.

arachidonic acid Polyunsaturated fatty acid (C20:4 o>6). Not strictly essential, since it can be formed from linoleic acid, but three times more potent than linoleic acid in curing the signs of essential fatty acid deficiency. arachin One of the globulin proteins from the peanut. arachis oil See peanut oil. aragula See rocket.

Arbroath smokie Smoked haddock; unlike finnan haddock not split but smoked whole to a dull copper colour.

arbute Fruit of the South European strawberry tree (Arbutus unedo); resembles strawberries in appearance but with little taste and a grainy texture. archaea Formerly classified as bacteria, then archaebacteria, now recognised as a separate type of prokaryotic organism, genetically distinct from bacteria; they are chemo-autrophic extremophiles, surviving at very high or very low temperatures. areca nut See betel.

arginase Enzyme (EC that hydrolyses arginine to urea and ornithine, the last stage of urea synthesis. argininaemia A genetic disease due to lack of arginase affecting the formation of urea and elimination of nitrogenous waste. Depending on the severity of the condition, affected infants may become comatose and die after a moderately high intake of protein. Treatment is by severe restriction of protein intake.

Sodium benzoate (see benzoic acid) may be given to increase the excretion of nitrogenous waste as hippuric acid. arginine A basic amino acid; abbr Arg (R), Mr 174.2, pKa 1.83, 8.99,12.48 (guanido), codons CGNu,AGPu. Not a dietary essential for adult human beings, but infants may not be able to syn-thesise enough to meet the high demands of growth so some may be required in infant diets. argininosuccinic aciduria A genetic disease due to lack of argini-nosuccinase (EC affecting the formation of urea and elimination of nitrogenous waste. Depending on the severity of the condition, affected infants may become comatose and die after a moderately high intake of protein. Treatment is by restriction of protein intake and feeding supplements of the amino acid arginine, which permits elimination of nitrogenous waste as argininosuccinic acid.

Sodium benzoate (see benzoic acid) may be given to increase the excretion of nitrogenous waste as hippuric acid. argol Crust of crude cream of tartar (potassium acid tartrate) which forms on the sides of wine vats, also called wine stone. It consists of 50-85% potassium hydrogen tartrate and 6-12% calcium tartrate, and will be coloured by the grapes, so white argol comes from white grapes and red argol from red grapes. Used in vinegar fermentation, in the manufacture of tartaric acid and as a mordant in dyeing. ariboflavinosis Deficiency of riboflavin (vitamin b2) characterised by swollen, cracked, bright red lips (cheilosis), an enlarged, tender magenta-red tongue (glossitis), cracking at the corners of the mouth (angular stomatitis), congestion of the blood vessels of the conjunctiva and a characteristic dermatitis with filiform (wire-like) excrescences.

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The Miracle Of Vinegar

The Miracle Of Vinegar

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