Tài liệu Tự điển Food Science, Technology And Nutrition - Vần U,V,W ppt

tion, 2 = toxin produced in host without adherence, 3 = toxin pro-
duced in host with adherence to cells,4 = toxin produced by inva-
sive bacteria, 5 = toxin produced by bacteria causing systemic
infection; type of toxin: 1 = enterotoxin, 2 = neurotoxin, 3 = non-
protein toxin; target or mechanism of action; individual toxin
number. Shown as TX x.x.x.x.
Tyndall effect Dispersion of light by a colloidal suspension (see
colloid), commonly determined as turbidity by measuring the
light emitted at 90° to the direction of incident light.
typhoid Gastrointestinal infection caused by Salmonella
typhi, transmitted by food or water contaminated by faeces of
patients or asymptomatic carriers. Paratyphoid is due to S.
paratyphi.
tyramine The amine formed by decarboxylation of the amino
acid tyrosine; chemically p-hydroxyphenylethylamine.
tyrosinase See phenol oxidases.
tyrosine A non-essential amino acid, abbr Tyr (Y), M
r
181.2, pK
a
2.43, 9.11, 10.13 (—OH), codons UAPy. Can be formed from the
essential amino acid phenylalanine, hence it has some sparing
action on phenylalanine. In addition to its role in proteins,
tyrosine is the precursor for the synthesis of melanin (the black
and brown pigment of skin and hair), and for adrenaline and
noradrenaline.
tyrosinosis genetic disease due to lack of p-hydroxyphenylpyru-
vate oxidase (EC 1.13.11.27), affecting the metabolism of tyro-
sine and leading to excretion of p-hydroxyphenylpyruvate in the
urine. Treatment is by restriction of dietary intake of pheny-
lalanine and tyrosine.

tzatziki Greek; grated cucumber in yogurt, flavoured with garlic,
olive oil and vinegar.
U
ubichromenol Cyclised derivatives of ubiquinones.
ubiquinones Coenzymes in the respiratory (electron transport)
chain in mitochondria, also known as coenzyme Q or mito-
quinones; widely distributed in nature. Chemically, derivatives of
benzoquinone with isoprene side chains. There is no evidence
that they are dietary essentials; they may have antioxidant
activity.
ucuhuba butter A yellow solid fat obtained from ucuhuba nuts,
the fruit of Myristica surinamensis. 90% saturated, 7% mono-
unsaturated, 3% polyunsaturated, vitamin E 0.6mg/100mL.
udon Japanese; fine transparent noodles made from wheat.
UFA Unesterified fatty acids, see fatty acids, non-esterified.
485
ugli citrus fruit; cross between grapefruit and tangerine, also
called tangelo (USA); first produced in Jamaica in 1930.
UHT See ultra-high-temperature sterilisation.
UL Tolerable upper intake level of a nutrient; maximum intake
(from supplements and enriched foods) that is unlikely to pose
a risk of adverse effects on health.
ulcer A crater-like lesion of the skin or a mucous membrane result-
ing from tissue death associated with inflammatory disease,infec-
tion or cancer.Peptic ulcers affect regions of the gastrointestinal
tract exposed to gastric juices containing acid and pepsin: gastric
ulcer in the stomach and duodenal ulcer in the duodenum.
Treatment was formerly conservative, with a bland diet, fol-
lowed if necessary by surgery. Now treated by inhibition of
gastric acid secretion using histamine receptor antagonists or

inhibitors of the proton pump. May be caused or exacerbated by
infection with Helicobacter pylori.
ulcerative colitis See colitis.
ullage Air space left in cask or bottle after some liquid has been
removed.
ultracentrifuge See centrifuge.
ultrafiltration Procedure for removal of low molecular weight
compounds from plasma, protein solutions, etc., using a
semipermeable membrane and either hydrostatic pressure or
centrifugation.
ultra-high-temperature sterilisation (UHT) Sterilisation at higher
temperatures and for shorter times, than high-temperature
short-time sterilisation.
ultrasound Sound above the normal range of human hearing,
commonly above 20kHz.
ultraviolet (UV) irradiation Light of wavelength below the
visible range. Wavelength for maximal germicidal action is
260nm; poor penetrating power and of value only for surface
sterilisation or sterilising air and water. Also used for tenderis-
ing and ageing of meat, curing cheese, and prevention of mould
growth on the surface of bakery products. Ultraviolet from sun-
light is responsible for skin tanning, and the formation of vitamin
d from 7-dehydrocholesterol in the skin.
umami Name given to the special taste of monosodium gluta-
mate, some other amino acids, protein and the ribonucleotides
(inosinate and guanylate). The Japanese name for a savoury
flavour, now considered one of the five basic senses of taste.
umbles Edible entrails of any animal (especially deer) which used
to be made into pie, umble pie or humble pie.
uncoupling proteins Proteins in mitochondria that act to uncou-

ple the processes of electron transport and oxidative phospho-
486
rylation, so permitting more or less uncontrolled oxidation of
metabolic fuels, with production of heat. An important part of
maintenance of body temperature by non-shivering thermogen-
esis, and maintenance of energy balance; they are stimulated by
leptin.
UCP-1 (thermogenin) is the best studied. It occurs in brown
adipose tissue (see adipose tissue, brown), and is activated by
free fatty acids produced in response to β-adrenergic stimulation.
UCP-2 occurs in a variety of tissues, including skeletal muscle
and lung; UCP-3 occurs only in skeletal muscle.
uncrystallisable syrup See syrup.
unesterified fatty acids (UFA) See fatty acids, non-esterified.
UNICEF United Nations Children’s fund; web site
/>universal product codes (UPC) Standard multidigit numbers that
represent product, size, manufacturer and nature of contents, on
food and other labels as machine-readable bar codes.
unsaponifiable See non-saponified.
unsaturated fatty acids See fatty acids.
UNU United Nations University; web site />UPC See universal product codes.
uperisation A method of sterilising milk by injecting steam under
pressure to raise the temperature to 150°C. The added water is
evaporated off.
uracil A pyrimidine; see nucleic acids.
urataemia High blood concentration of uric acid and its salts, as
in gout.
uraturia Urinary excretion of high concentrations of uric acid
and its salts.
urd bean See grams, indian.

urea CO(NH
2
)
2
, the end-product of nitrogen metabolism in most
mammals, excreted in the urine. Synthesised in the liver from
ammonia (arising from the deamination of amino acids) and the
amino acid aspartic acid. It is the major nitrogenous compound
in urine, and the major component of the non-protein nitrogen
in blood plasma.
urease Intestinal bacterial enzyme (EC 3.5.1.5) that hydrolyses
urea to ammonia and carbon dioxide. Important in the entero-
hepatic cycling of urea. Also found in some beans.
urethane Ethyl carbamate, used as intermediate in organic syn-
theses, as a solubiliser and as the precursor for polyurethane
foam. Found in small amounts in liqueurs made from stone fruits,
wines and some distilled spirits where it is formed by reaction
between alcohol and nitrogenous compounds; cause for concern
since it is genotoxic, and hence a potential carcinogen.
487
uric acid The end-product of purine metabolism in human beings
and other apes; most other mammals have the enzyme uricase
(EC 1.7.3.3), which oxidises uric acid to allantoin, which is more
soluble in water. gout is the result of excessive formation of uric
acid, and/or impaired excretion; it is only slightly soluble in
water, and in excess it crystallises in joints, as gouty nodules
(tophi) under the skin and sometimes in the kidney.
urobilinogen Pigment in urine derived from the bile pigments,
which, in turn, are formed from haemoglobin. When urine is left
to stand, the urobilinogen is oxidised in air to urobilin.

urogastrone Name given to a peptide found in urine that
inhibits gastric secretion, (nearly) identical to epidermal growth
factor.
urwaga See orubisi.
USDA US Department of Agriculture, created as an independent
department in 1862; web site />USRDA reference intakes used for nutritional labelling of
foods in the USA before the introduction of daily values.
uszka Polish; type of ravioli, egg-flour dough stuffed with
mushrooms.
UV See ultraviolet.
V
vacherin (1) Circular cakes of meringue and cream.
(2) French mild cheeses made from cow’s milk; traditionally
moulded in flat circles and wrapped in a border of bark.
vac-ice process Alternative name for freeze drying.
vacreation deodorisation of cream by steam distillation under
reduced pressure; developed in New Zealand.
vacuum contact drying Or vacuum contact plate process, a
method of drying food in a vacuum oven in which the material
is heated by hot plates both above and below. As the material
shrinks due to water loss, continuous contact is maintained by
closing the plates; heats the food more effectively than a simple
vacuum oven.
vada Indian; spiced, deep fried balls of legume flour that has been
left overnight to undergo a lactic acid bacterial fermentation,
together with Leuconostoc mesenteroides, which produces
carbon dioxide as a leavening agent.
vagotomy Surgical cutting of part of the vagus (10th cranial)
nerve, usually to reduce secretion of acid and pepsin by the
gastric mucosa.

valerian Extracts and the essential oil of the herbaceous peren-
nial Valeriana officianalis are used as flavouring in many foods.
488
The root has traditionally been used as a sedative and tranquil-
liser, with evidence of efficacy.
valgus Any deformity that displaces the hand or foot away from
the mid-line of the body; e.g. genu valgus is knock knees, as seen
in rickets.
See also varus.
validity Of an assay, the extent to which a method measures what
it purports to measure.
See also accuracy; precision; sensitivity; specificity.
valine An essential amino acid, abbr Val (V), M
r
117.1, pK
a
2.29,
9.74, codons GUNu; rarely, if ever, limiting in foods.
valzin, valzol See dulcin.
vanadium A mineral known to be essential to experimental
animals, although sufficiently widespread for human dietary defi-
ciency to be unknown. Its precise function is unknown, although
it acts as an activator of a number of enzymes.
vanaspati Indian; purified hydrogenated vegetable oil; similar to
margarine and usually fortified with vitamins A and D. Also
used to prepare ghee (vanaspati ghee).
vanilla Extract of the vanilla bean, fruit of the tropical orchid
Aracus (or Vanilla) aromaticus and related species. Discovered
in Mexico in 1571 and could not be grown elsewhere, because
pollination could be effected only by a small Mexican bee, until

artificial pollination was introduced in 1820. Main growing
regions now Madagascar and Tahiti.
The major flavouring principle is vanillin (chemically methyl
protocatechuic aldehyde), but other substances present aid the
flavour. Ethyl vanillin is a synthetic substance which does not
occur in the vanilla bean; 3.5 times as strong in flavour, and more
stable to store than vanillin, but does not have the true flavour.
vanillin See vanilla.
VaporPrint
TM
imaging A graphical representation of the flavour
profile obtained using a znose
TM
‘electronic nose’.
variety meat American name for offal.
varus Any deformity that displaces the hand or foot towards the
mid-line of the body; e.g. genu varus is bow legs, as seen in
rickets.
See also valgus.
vasoactive intestinal peptide (VIP) Protein secreted by the
pancreas; over-secretion can cause severe diarrhoea.
vasoconstriction Constriction of the blood vessels; the reverse of
vasodilatation.
vasodilatation (vasodilation) Dilation of the blood vessels; the
reverse of vasoconstriction. Caused by a rise in body tempera-
ture; serves to lose heat from the body.
489
vasopressin Antidiuretic hormone secreted by the pituitary; acts
to increase resorption of water in the kidneys and to constrict
blood vessels.

VCD See vacuum contact drying.
VDP Volatile decomposition products.
veal Meat of young calf (Bos taurus) 2
1
/
2
–3 months old.
Composition/100g: water 76g, 456kJ (109kcal), protein 20.3g,
fat 2.5g (of which 42% saturated, 42% mono-unsaturated, 16%
polyunsaturated), cholesterol 84mg, carbohydrate 0g, ash 1.1g,
Ca 17mg, Fe 0.9mg, Mg 25mg, P 213mg, K 331mg, Na 83mg,
Zn 3.5mg, Cu 0.1mg, Se 8.8 µg, vitamin E 0.3mg, B
1
0.09mg,
B
2
0.29mg, niacin 7.4mg, B
6
0.45mg, folate 13µg, B
12
1.5µg,
pantothenate 1.3mg. A 100g serving is a source of Se, vitamin
B
2
,a good source of P, Zn,vitamin B
6
, pantothenate, a rich source
of niacin, vitamin B
12
.

vegans Those who consume no foods of animal origin. See
vegetarians.
Vegemite
TM
Australian; yeast extract.
vegetable See fruit.
vegetable butters See cocoa butter equivalents; cocoa butter
substitutes.
vegetable oyster See salsify.
vegetable pepsin See papain.
vegetable protein products General term to include textured soya
and other bean products, often made to simulate meat (see tex-
tured vegetable protein).The basic material is termed flour
when the protein content is not less than 50%; concentrate, not
less than 65%; isolate, not less than 90% protein.
vegetable spaghetti See spaghetti squash.
vegetarians Those who do not eat meat or fish, either for
ethical/religious reasons or because they believe that a meat-free
diet confers health benefits.Apart from a risk of vitamin b
12
defi-
ciency, there are no adverse effects of a wholly meat-free diet,
although vegetarian women are more at risk of iron deficiency
than those who eat meat. Vitamin B
12
is found only in meat and
meat products, but supplements prepared by bacterial fermenta-
tion (and hence ethically acceptable to the strictest of vegetari-
ans) are available.
The strictest vegetarians are vegans,who consume no products

of animal origin at all. Those who consume milk and milk prod-
ucts are termed lacto-vegetarians; those who also eat eggs, ovo-
lacto-vegetarians. Some vegetarians (pescetarians) will eat fish,
but not meat; demi-vegetarians eat little or no meat, or eat
poultry but not red meat.
veitchberry Variety of loganberry.
veltol See maltol.
490
venison Meat of deer (Odocoileus spp.); traditionally game, but
now mainly farmed.
Composition/100g: water 74g, 502kJ (120kcal), protein 23g,
fat 2.4g (of which 43% saturated, 33% mono-unsaturated, 24%
polyunsaturated), cholesterol 85mg, carbohydrate 0g, ash 1.2g,
Ca 5mg, Fe 3.4mg, Mg 23mg, P 202mg, K 318mg, Na 51mg,
Zn 2.1mg, Cu 0.3mg, Se 9.7µg, vitamin E 0.2mg, K 1.1mg,
B
1
0.22mg, B
2
0.48mg, niacin 6.4mg, B
6
0.37mg, folate 4µg, B
12
6.3µg, A 100g serving is a source of Se, Zn, vitamin B
1
,B
6
,a good
source of Cu, Fe, P, a rich source of vitamin B
2

, niacin, B
12
.
venting Removal of air from a retort or retort pouch before
heating.
verbascose A non-digestible tetrasaccharide, galactosyl-
galactosyl-glucosyl-fructose, found in legumes; fermented by
intestinal bacteria and causes flatulence.
verbena A lemon flavoured herb, the leaves of Lippia citroidora.
verdoflavin Name given to a substance isolated from grass, later
shown to be riboflavin (vitamin b
2
).
verjuice Literally green juice; sour juice of crab apples (and
sometimes unripe grapes) formerly used in cooking meat, fish
and game dishes. Now normally replaced by lemon juice.
vermicelli See pasta.
vermicide Any drug used to kill or expel intestinal parasitic
worms.
vermouth Fortified wine (about 16% alcohol by volume)
flavoured with herbs and quinine.French vermouth is dry and
colourless; Italian may be red or white and is sweet. Drunk as an
apéritif, either with soda or with gin or vodka (when called a
martini). Name originally derived from German Wermut for
wormwood, a toxic ingredient that was included in early ver-
mouths (as in absinthe).
Sweet or Italian vermouth, 15–17% alcohol (by volume),
12–20% sugar (by weight). Dry or French type 18–20% alcohol,
3–5% sugar.
Versene

TM
Ethylenediamine tetra-acetic acid, see edta.
Verv
TM
Calcium stearyl-2-lactate, used to reduce baking varia-
tions in flour. It produces a more extensible dough, more easily
machined, and gives a loaf with better keeping properties and
more uniform structure.
vervain Herb (Verbena officianilis) used to make herb tea.
very low-density lipoproteins (VLDL) See lipoproteins, plasma.
vetch Old term applied generally to legumes; originally Vicia
spp., also called tares.
ve-tsin See monosodium glutamate.
Vibrio cholerae The causative agent of cholera, bacterium trans-
mitted especially through water; forms an enterotoxin after
491
adhering to epithelial cells in gut. Infective dose 10
8
organisms,
onset 2–5 days, duration 4–6 days, TX 3.1.2.2.
vichyssoise Leek and potato cream soup, served cold.
vicilin Globulin protein in pea and lentil.
vicine One of the toxins in broad beans, responsible for acute
haemolytic anaemia or favism.
victory bread American; recipe for bread containing soya flour to
spare wheat, in a circular published by the US Secretary of Agri-
culture in 1918.
Vienna flour Specially fine flour used to make strudel pastry,
Vienna bread and cakes.
Viennese coffee Ground coffee containing dried figs.

viili Finnish; yogurt made using Streptococcus cremoris as the
main organism.
villi, intestinal Small, finger-like processes covering the surface of
the small intestine in large numbers (20–40/mm
2
), projecting
some 0.5–1mm into the lumen. They provide a surface area of
about 300m
2
for the absorption of nutrients from the small
intestine.
See also gastrointestinal tract.
vinasses The residual liquors from sugar beet molasses; contain
appreciable quantities of betaine.
vinegar A solution of acetic acid (not less than 4%); the product
of two fermentations, first with yeast to convert sugars into
alcohol; this liquor,called gyle (6–9% alcohol),is then fermented
with Acetobacter spp. to form acetic acid. In most countries
vinegar is made from grape juice (wine vinegar,may be from red,
white or rosé wine).
vinegar, balsamic Made from grape juice that has been concen-
trated over a low flame and fermented slowly in a series
of wooden barrels; traditionally made only around Modena,
Italy.
vinegar, cider Made from apple juice, and known simply as
vinegar in the USA.
vinegar, malt Made from malted barley and may be distilled to a
colourless liquid with the same acetic acid content but a more
mellow flavour.
vinegar, non-brewed (or non-brewed condiment) A solution of

acetic acid, 4–8%, coloured with caramel.
vinegar, rice Made from saké.
vine leaves Leaves of the grape vine, Vitis vinifera, used in
Mediterranean cuisine.
Composition/100g: (edible portion 95%) water 73g, 389kJ
(93kcal), protein 5.6g, fat 2.1g (of which 20% saturated, 7%
mono-unsaturated, 73% polyunsaturated), carbohydrate 17.3g
492
(6.3g sugars), fibre 11g, ash 1.6g, Ca 363mg, Fe 2.6mg, Mg 95mg,
P 91mg, K 272mg, Na 9mg, Zn 0.7mg, Cu 0.4mg, Mn 2.9mg,
Se 0.9µg, vitamin A 1376µg RE (18579µg carotenoids), E 2mg,
K 108.6mg, B
1
0.04mg, B
2
0.35mg, niacin 2.4mg, B
6
0.4mg, folate
83µg, pantothenate 0.2mg, C 11mg.
vinification The process of fermentation of sugars in grape juice
to make wine.
viosterol Irradiated ergosterol; vitamin d
2
.
VIP See vasoactive intestinal peptide.
Virginia date See persimmon.
Virol
TM
A vitamin preparation based on malt extract.
virpa See sowans.

viscera The organs within a body cavity, used especially for the
abdominal viscera, liver, spleen, gastrointestinal tract,
kidneys, etc.
viscoelastic Material such as cheese, dough or gelled food, that
has both viscous and elastic properties (see viscosity);when a
shear stress is removed it does not return to its original shape,
but is deformed.
viscogen Thickening agent for whipping cream.Two parts of
lime (calcium oxide) in six parts of water, added to five parts
of sugar in ten parts of water; used at the rate of 3–6g/L of
cream.
viscometer Instrument for measuring the viscosity of liquids.
viscosity Of a liquid or gas, its resistance to flow. Decreases with
increasing temperature for liquids, but increases for gases.
Dynamic viscosity is the ratio of shear stress :shear rate.
Kinematic viscosity is dynamic viscosity/density.
See also dilatant; plastic fluids; pseudoplastic; reynolds
number; rheopectic; thixotropic; viscoelastic.
viscosity, dynamic (or absolute) The ratio of shear stress : shear
rate for fluids that exhibit a linear relationship between shear
stress and shear rate (Newtonian flow).
vision The process of vision is mediated by photosensitive pig-
ments formed by reaction between retinaldehyde (vitamin a
aldehyde) and the protein opsin. The pigments are known vari-
ously as visual purple (because of its colour), rhodopsin (in the
rod cells of the retina) and iodopsin (in the cone cells, with sen-
sitivity to different wavelengths of light in different cells). Expo-
sure to light results in bleaching of the pigment, with loss of the
retinaldehyde and a conformational change in the protein, which
leads to closure of a sodium channel in the retinal cell, and ini-

tiation of a nerve impulse.
visual pigments, visual purple See vision.
vitafoods Foods designed to meet the needs of health-conscious
493
consumers that enhance physical or mental quality of life and
may increase health status.
vitamers Chemical compounds structurally related to a vitamin,
and converted to the same active metabolites in the body. They
thus possess the same kind of biological activity, although some-
times with lower potency.
When there are several vitamers, the group of compounds
exhibiting the biological activity of the vitamin is given a generic
descriptor (e.g. vitamin a is the generic descriptor for retinol
and its derivatives as well as several carotenoids).
vitamin There are 13 organic compounds (thus excluding trace
minerals) essential to human life in very small amounts. Eleven
of these must be supplied in the diet (vitamins A, B
1
,B
2
,B
6
,B
12
,
C, E, K, folic acid, biotin and pantothenic acid); two (niacin
and vitamin d) can be made in the body if there is sufficient of
the amino acid, tryptophan, and sunlight, respectively. The word
may be pronounced either veitamin or vittamin.
Vitamins A, D, E and K are grouped together as fat-soluble

vitamins, because they are soluble in lipids, but not in
water. Vitamin C and the B vitamins (including pantothenic
acid, biotin and folic acid) are grouped together as the water-
soluble vitamins since they are all soluble in water, but not
lipids.
vitamin A (see p. 495) Fat-soluble vitamin, occurring either as the
preformed vitamin (retinol) found in animal foods or as a pre-
cursor (carotenes) found in plant foods. Required for control of
growth, cell turnover and fetal development, maintenance of fer-
tility and maintenance of the normal moist condition of epithe-
lial tissues lining the mouth and respiratory and urinary tracts;
essential in vision.The main active metabolites in the body are
retinaldehyde, all-trans- and 9-cis-retinoic acids.
Deficiency leads to slow adaptation to see in dim light (poor
dark adaptation), later to night blindness; then drying of the
tear ducts (xerophthalmia) and ulceration of the cornea (ker-
atomalacia) resulting in blindness.
The vitamin A content of foods is expressed as retinol
equivalents, i.e. retinol plus carotene; 1µg retinol = 6µg β-
carotene = 12µg other active carotenoids = 3.33 international
units.
See also conjunctival impression cytology; relative dose
response test; retinol binding protein; vision.
vitamin A toxicity Retinol in excess of requirements is stored in
the liver, bound to proteins, and is a cumulative poison. When
the storage capacity is exceeded, free retinol causes damage to
cell membranes. carotene is not toxic in excess, since there is
only a limited capacity to form retinol from carotene.
494
The recommended upper limits of habitual daily intake of

retinol are about 12.5 × reference intake for adults, but only 2.5
× reference intake for infants. Retinol is also teratogenic in
excess, and for pregnant women the recommended upper limit
of daily intake is 3000–3300µg.
vitamin A
2
Old name for dehydroretinol, the form found in livers
of freshwater fish; has 40% of the biological activity of retinol.
vitamin B complex Old-fashioned term for the various B
vitamins: vitamin b
1
(thiamin), vitamin b
2
(riboflavin), niacin,
vitamin b
6
, vitamin b
12
, folic acid, biotin and pantothenic acid.
These vitamins occur together in cereal germ, liver and yeast;
function as coenzymes; and historically were discovered by sep-
aration from what was known originally as ‘vitamin B’; hence,
they are grouped together as the B complex.
vitamin B
1
Thiamin. Thiamin diphosphate is a coenzyme in
metabolism of glucose, and in the citric acid cycle. Thiamin
triphosphate has a role in nerve conduction, by activating a chlo-
ride channel. Deficiency, especially when associated with a
carbohydrate-rich diet, results in the disease beriberi, degenera-

tion of the sensory nerves in the hands and feet, spreading
through the limbs, with fluid retention and heart failure. Rela-
tively acute deficiency, especially associated with alcohol abuse,
495
VITAMIN A
results in central nervous system damage, the wernicke–
korsakoff syndrome.
See also thiochrome; transketolase.
496
vitamin B
1
dependency syndromes A very small number of chil-
dren have been reported with a variant form of maple syrup
urine disease in which the defect is in the binding of thiamin
diphosphate to the branched chain keto acid dehydrogenase (EC
1.2.4.4). These children respond well to supplements of large
amounts of vitamin B
1
, without the need for strict control of their
intake of the amino acids.
vitamin B
2
Riboflavin. Coenzyme in a wide range of oxidation
reactions of fats, carbohydrates and amino acids, as riboflavin
phosphate (flavin mononucleotide), flavin adenine dinucleotide
or covalently bound riboflavin at the active site of the enzyme.
Riboflavin-dependent enzymes are collectively known as
flavoproteins.
Deficiency impairs energy-yielding metabolism and results in
a group of symptoms known as ariboflavinosis, including crack-

ing of the skin at the corners of the mouth (angular stomatitis),
fissuring of the lips (cheilosis) and tongue changes (glossitis);
seborrhoeic accumulations appear around the nose and eyes.Not
fatal because there is very efficient recycling of riboflavin in
deficiency.
See also glutathione reductase; lumichrome; lumiflavin.
VITAMIN B
1
VITAMIN B
2
vitamin B
3
Term once used for pantothenic acid and sometimes,
incorrectly, used for niacin.
vitamin B
4
Name given to what was later identified as a mixture
of the amino acids arginine, glycine and cystine.
vitamin B
5
Name given to a substance later presumed to be iden-
tical with vitamin B
6
or possibly nicotinic acid: also sometimes
used for pantothenic acid.
vitamin B
6
Generic descriptor for three compounds (chemically
derivatives of 2-methylpyridine): the hydroxyl (alcohol) com-
pound,pyridoxine (previously known as adermin and pyridoxol);

the aldehyde, pyridoxal; and the amine, pyridoxamine; and
their phosphates. All are equally active biologically. The active
metabolite is pyridoxal 5′-phosphate, which acts as a coenzyme
in decarboxylation and transamination of amino acids, and in
glycogen phosphorylase (EC 2.4.1.1), it also has a role in termi-
nating the actions of steroid hormones.
Deficiency causes abnormalities in the metabolism of the
amino acids tryptophan and methionine; in rats convulsions and
skin lesions (acrodynia) and in dairy cows and dogs, anaemia
with abnormal red blood cells. Dietary deficiency leading to clin-
ical signs is not known in human beings, apart from a single out-
break in babies fed a severely overheated preparation of formula
milk in the 1950s; they showed abnormalities of amino acid
metabolism and convulsions resembling epileptic seizures, which
responded to supplements of the vitamin.
See also methionine load test; transaminase; tryptophan
load test.
497
vitamin B
6
dependency syndromes A very small number of chil-
dren suffer from genetic diseases affecting the binding of
pyridoxal phosphate to just one of the pyridoxal phosphate-
VITAMIN
B
6
dependent enzymes.The abnormality is corrected by the admin-
istration of large supplements of vitamin B
6
.

vitamin B
6
toxicity High intakes of supplements of vitamin B
6
,
in excess of 200–1000mg/day (far in excess of what could be
obtained from foods) cause peripheral sensory neuropathy.
vitamin B
7
,B
8
and B
9
In the early days of nutrition research, when
a new factor was discovered that was claimed to be essential for
chick growth and feathering, the claimant stated that since nine
factors were known the new factors should be called vitamins B
10
and B
11
. In fact, the B vitamins had been numbered only up to
B
6
, hence B
7
,B
8
and B
9
have never existed. B

9
is sometimes
(incorrectly) used for folic acid.
vitamin B
10
and B
11
The names given to two factors claimed to be
essential for chick growth and feathering; they were later shown
to be a mixture of vitamin B
1
and folic acid.
vitamin B
12
(see p. 499) Cobalamin; coenzyme for methionine
synthetase (EC 2.1.1.13, important in metabolism of folic acid),
methylmalonyl CoA mutase (EC 5.4.99.2) and leucine aminomu-
tase (EC 5.4.3.7).
Deficiency leads to pernicious anaemia when immature red
blood cells are released into the bloodstream, and there is degen-
eration of the spinal cord. The anaemia is the same as seen in
folate deficiency, and is due to impairment of folate metabolism.
There is also urinary excretion of methylmalonic acid.
Absorption of vitamin B
12
requires intrinsic factor,a protein
secreted in the gastric juice. Failure of absorption, rather than
dietary deficiency, is the main cause of pernicious anaemia.
However, B
12

is found only in animal foods so strict vegetarians
are at risk.
See also dump suppression test; methyl folate trap;
schilling test.
vitamin B
13
Orotic acid, an intermediate in pyrimidine synthesis;
no evidence that it is a dietary essential; not a vitamin.
vitamin B
14
Not an established vitamin; name originally given to
a compound found in human urine that increases the rate of cell
proliferation in bone marrow culture.
vitamin B
15
pangamic acid; no evidence that it has any physio-
logical function in the body; not a vitamin.
vitamin B
16
This term has never been used.
vitamin B
17
amygdalin (laetrile); no evidence that it has any
physiological function in the body; not a vitamin.
vitamin B
C
Obsolete name for folic acid.
vitamin B
D
Called the antiperosis factor for chicks, but can be

replaced by manganese and choline (not a dietary essential for
human beings).
498
vitamin B
T
carnitine; an essential dietary factor for the meal-
worm Tenebrio molitor, and certain related species, but not a
dietary essential for human beings.
vitamin B
W
Or factor W; probably identical to biotin.
vitamin B
X
Non-existent; has been used in the past for both
pantothenic acid and PARA-amino benzoic acid.
vitamin C ascorbic acid.For formula, see p. 39. It functions as
a cofactor for a group of hydroxylases that also catalyse the
decarboxylation of 2-oxoglutarate (including the hydroxylation
of lysine and proline in the synthesis of collagen, and two
hydroxylases in the synthesis of carnitine); in these reactions it
is consumed, but not stoichiometrically with substrates. It is also
the coenzyme for dopamine β-hydroxylase (EC 1.14.17.1) in the
499
VITAMIN B
12
synthesis of noradrenaline, and peptidyl glycine hydroxylase
(EC 1.14.17.3) in the post-synthetic modification of a number of
peptide hormones. It is a general (non-enzymic) antioxidant,
including the reduction of oxidised vitamin e in cell membranes.
Deficiency results in scurvy: seepage of blood from capillar-

ies, subcutaneous bleeding, weakness of muscles, soft, spongy
gums and loss of dental cement, leading to loss of teeth and in
advanced cases deep bone pain. A lesser degree of deficiency
results in impaired healing of wounds.
The requirement to prevent scurvy is less than 10mg/day; ref-
erence intakes range between 30 and 85mg/day, depending on
the criteria of adequacy adopted and the assumptions made in
the interpretation of experimental data. At intakes above
100mg/day the vitamin is excreted in the urine; there is no
evidence of any adverse effects at intakes up to 4000mg/day.
Fruits and vegetables are rich sources; also used in curing ham,
and as an antioxidant and bread improver.
See also dichlorophenol indophenol; erythorbic acid; iron;
o-phenylene diamine; oxalic acid.
vitamin D (see p. 501) Vitamin D
3
is calciol or cholecalciferol;
formed in the skin by the action of ultraviolet light on 7-dehy-
drocholesterol,hence not strictly a vitamin.However, in north-
ern latitudes sunlight exposure may not be adequate to meet
requirements, and a dietary source becomes essential.
Vitamin D
2
(ercalciol or ergocalciferol) is a synthetic vitamer
produced by irradiation of ergosterol. The name vitamin D
1
was
given originally to an impure mixture and is not used now.
The main storage form of the vitamin is the 25-hydroxy
derivative, calcidiol, in plasma; the active metabolite is the

1,25-dihydroxy derivative, calcitriol. Formation of calcitriol is
regulated by the state of calcium balance.
The function of calcitriol is mainly in regulation of calcium
metabolism; it acts via nuclear receptors,like a steroid hormone,
and also via cell-surface receptors. Stimulates absorption of
dietary calcium from the small intestine and calcium turnover in
bone, by activating osteoblasts to mobilise calcium, then later
recruiting and stimulating differentiation of osteoblast precur-
sors for bone formation. Acting to regulate intracellular calcium
concentrations, it is important in control of the secretion of
insulin and other hormones. It also has a role (together with
vitamin a) in regulation of cell differentiation and replication,
and control of the cell cycle.
Deficiency causes rickets in young children, osteomalacia in
adults.
Not widely distributed in foods; egg yolk, butter, oily fish and
enriched margarine are the only significant sources. Reference
500
intakes are 10–15µg/day for adults, amounts that are unlikely to
be obtained from unsupplemented diets.
The obsolete international unit of vitamin D = 25 ng calciol;
1mg calciol = 40IU.
vitamin D resistant rickets See rickets.
vitamin D toxicity Excessive intake of vitamin D results in dis-
turbance of calcium metabolism, resulting in hypercalcaemia,
dangerously raised blood calcium concentrations, leading to
raised blood pressure, and calcinosis, inappropriate deposition
of calcium in soft tissues, leading to brain and kidney damage.
Excessive exposure to sunlight does not lead to excessive for-
mation of vitamin D because previtamin D undergoes further

light-catalysed reactions to inactive compounds,and there is only
limited availability of 7-dehydrocholesterol in the skin.
vitamin E (see p. 502) Two main groups of compounds have
vitamin E activity: the tocopherols and the tocotrienols;there are
four isomers of each: α-, β-, γ- and δ-tocopherols and α-, β-, γ-
and δ-tocotrienols, with differing potencies.
Deficiency symptoms vary considerably in different animal
species; sterility in mouse, rat, rabbit, sheep and turkey; muscu-
lar dystrophy in several species; capillary permeability in chick
and turkey; anaemia in monkey. Human dietary deficiency is
unknown, but hereditary lack of β-lipoprotein leads to functional
deficiency, with severe neurological damage. Premature infants
may show haemolytic anaemia as a result of vitamin E deficiency.
Functions as an antioxidant in cell membranes, protecting
unsaturated fatty acids from oxidative damage. It also has
membrane-specific functions, and a role in cell signalling and
modulation of gene expression.
The vitamin E content of foods is expressed as milligrams α-
tocopherol equivalent (based on the different potency of the dif-
ferent vitamers). The obsolete international unit of vitamin E
501
VITAMIN D
activity was equal to 1mg of synthetic α-tocopherol; on this basis
natural source α-tocopherol is 1.49IU/mg.
vitamin F Sometimes used for the essential fatty acids.
vitamin G Obsolete name for vitamin b
2
.
502
VITAMIN E

vitamin H See biotin.
vitamin K Two groups of compounds have vitamin K activity:
phylloquinones (vitamin K
1
), found in all green plants, and a
variety of menaquinone (vitamin K
2
) synthesised by intestinal
bacteria. Vitamin K
3
is a synthetic analogue, menadione.
Functions as coenzyme in carboxylation of glutamate to γ-
carboxyglutamate in a number of calcium binding proteins,
including prothrombin and other proteins involved in the blood
clotting system, the bone protein osteocalcin, and the product
of the growth arrest-specific gene (Gas-6), which is important in
regulation of growth and development.
Dietary deficiency is unknown, except associated with general
malabsorption diseases. However, some newborn infants are at
risk of developing haemorrhagic disease as a result of low
vitamin K status, and it is general practice to give a single rela-
tively large dose of the vitamin by injection.
See also anticoagulants; dicoumarol; warfarin.
503
vitamin L Factors extracted from yeast and thought at the time
to be essential for lactation; they have not become established
vitamins.
vitamin M Obsolete name for folic acid.
vitaminoids Name given to compounds with ‘vitamin-like’ activ-
ity; considered by some to be vitamins or partially to replace

vitamins. Include flavonoids (vitamin p), inositol, carnitine,
choline, lipoic acid and the essential fatty acids (see fatty acids,
VITAMIN K
essential). With the exception of the essential fatty acids, there
is no evidence that any of them is a dietary essential.
vitamin P Name given to a group of plant flavonoids (sometimes
called bioflavonoids) that affect the strength of blood capillaries:
rutin (in buckwheat), hesperidin, eriodictin and citrin (a mixture
of hesperidin and eriodictin in the pith of citrus fruits). Now
considered that the effect is pharmacological and that they are
not dietary essentials, although they have antioxidant activity.
Called vitamin P from the German permeabilitäts vitamin,
because of the effect on capillary permeability and fragility.
vitamin PP The pellagra-preventing vitamin, an old name for
niacin before it was identified.
vitamin Q See ubiquinone.
vitamin T Factor found in insect cuticle, mould mycelia and yeast
fermentation liquor, claimed to accelerate maturation and
promote protein synthesis. Also known as torulitine. Said to be
a mixture of folic acid, vitamin B
12
and deoxyribosides (DNA);
hence not a particular vitamin.
vitellin The major protein of egg yolk; approximately 80% of the
total; a phosphoprotein accounting for 30% of the phosphorus
of egg yolk.
VLDL Very low-density lipoprotein, see lipoproteins, plasma.
VOC Volatile organic compounds
vodka Made from neutral spirit, i.e. alcohol distillate mainly from
potatoes, with little or no acid, so that there is no ester forma-

tion and hence no flavour. Polish vodka is flavoured with a
variety of herbs and fruits.
voidage The fraction of the total volume occupied by air (the
degree of openness) of a bed of material in fluidised-bed drying.
Vol
TM
Commercial ammonium carbonate, a mixture of ammo-
nium bicarbonate and carbamate. Used as aerating agent in
baking, as it breaks down to carbon dioxide, ammonia and steam
on heating, without leaving any residue.
volvulus Twisting of part of the gastrointestinal tract, leading
to partial or complete obstruction.
votator Machine used for the continuous manufacture of mar-
garine; the fat and water are emulsified, and the subsequent
conditioning process carried out in the same machine.
VP Vacuum packaging.
VSP Vacuum skin packaging.
W
wähe Swiss; tarts made from yeast-leavened dough filled with
fruit, vegetables or cheese.
waist: hip circumference ratio Simple method for describing the
504
distribution of subcutaneous and intra-abdominal adipose
tissue.
wakame Japanese; lobe leaf seaweed, normally dried.
Composition/100g: water 80g, 188kJ (45kcal), protein 3 g, fat
0.6g, carbohydrate 9.1g (0.6g sugars), fibre 0.5g, ash 7.2g, Ca
150mg, Fe 2.2mg, Mg 107mg, P 80mg, K 50mg, Na 872mg,
Zn 0.4mg, Cu 0.3mg, Mn 1.4mg, Se 0.7µg, vitamin A 18 µg RE
(216µg carotenoids), E 1mg, K 71.7mg, B

1
0.06mg, B
2
0.23mg,
niacin 1.6mg, folate 196µg, pantothenate 0.7mg, C 3mg.
walnuts The rough shelled English walnut, black walnut, hickory
nut and butternut are all botanically walnuts. Common English
walnut (so-called because carried round the world for centuries
in English ships) is Juglans regia.
Black walnuts, composition/100g: (edible portion 24%) water
4.6g, 2587kJ (618kcal), protein 24.1g, fat 59g (of which 6% sat-
urated, 28% mono-unsaturated, 66% polyunsaturated), carbo-
hydrate 9.9g (1.1g sugars), fibre 6.8g, ash 2.5g, Ca 61mg, Fe
3.1mg, Mg 201mg, P 513mg, K 523mg, Na 2mg, Zn 3.4mg, Cu
1.4mg, Mn 3.9mg, Se 17µg, vitamin A 2µg RE (33µg
carotenoids), E 1.8mg, K 2.7mg, B
1
0.06mg, B
2
0.13mg, niacin
0.5mg, B
6
0.58mg, folate 31µg, pantothenate 1.7mg, C 2mg. A
20g serving (3 nuts) is a source of Mg, P, a good source of Cu, a
rich source of Mn.
English walnuts, composition/100g: (edible portion 45%)
water 4.1g, 2738kJ (654kcal), protein 15.2g, fat 65.2g (of which
10% saturated, 14% mono-unsaturated, 76% polyunsaturated),
carbohydrate 13.7g (2.6g sugars), fibre 6.7g, ash 1.8 g, Ca 98 mg,
Fe 2.9mg, Mg 158mg, P 346mg, K 441mg, Na 2mg, Zn 3.1mg,

Cu 1.6mg, Mn 3.4mg, Se 4.9µg, vitamin A 1µg RE (21µg
carotenoids), E 0.7mg, K 2.7mg, B
1
0.34mg, B
2
0.15mg, niacin
1.1mg, B
6
0.54mg, folate 98µg, pantothenate 0.6mg, C 1mg. A
20g serving (3 nuts) is a good source of Cu, Mn.
Walnut oil is 10% saturated, 24% mono-unsaturated, 66%
polyunsaturated,contains 0.4 mg vitamin E,15 mg vitamin K/100 g.
wappato See arrowhead.
Warfarin Synthetic compound that acts as a vitamin k antagonist,
by inhibiting vitamin K epoxide reductase (EC 1.1.4.1). Used
clinically to impair blood clotting in patients at risk of thrombo-
sis, and as a rodenticide. Named for the Wisconsin Alumnus
Research Fund, which sponsored the research that led to its dis-
covery (1951).
Use of Warfarin in pregnancy can lead to fetal abnormalities
(the fetal Warfarin syndrome) as a result of inhibition of the
vitamin K-dependent carboxylation of the product of the growth
arrest-specific (Gas-6) gene, which is important in regulation of
growth and development.
505
wari Indian, Pakistani; dried balls of legume and cereal flour that
has undergone a yeast fermentation; can be stored for some
months, then deep fried.
wasabe Japanese; pungent condiment prepared from dried
horseradish and mustard.

wash, spent See spent wash.
wassail (1) Spiced ale.
(2) Salutation or toast drunk to a person’s health.
wastel Medieval English; fine white bread made from sifted flour.
water activity (a
w
) Ratio between vapour pressure of water in the
food and that of pure water at the same temperature. Most bac-
teria cannot grow at a
w
below 0.9, yeasts below 0.85 and moulds
below 0.7. So-called dehydrated foods have a
w
lower than 0.6.
water balance The balance between intake and excretion of
fluids. Average daily intakes are: as drinks 1–1.5L; as aqueous
part of food, 0.5L; and formed in the body by oxidation of food-
stuffs (metabolic water), 300–500mL; total 2–3L. Losses from
the lungs, 400–500mL; through the skin 400–500mL; in faeces
80–100mL; in urine 1–1.8L.
Total body water is 500 (female)–600 (male) mL/kg body
weight. Of this, 57% is intracellular and 43% extracellular; 7%
of the total is in blood plasma.
The kidney controls the volume of extracellular water by
excreting water. Ingestion of sodium chloride (salt) raises the
osmotic pressure of the extracellular water, causing thirst.
water binding capacity See meat, water binding capacity.
water biscuit See crackers.
water, bound Water that is physically or chemically bound to the
food matrix, so that it has a lower vapour pressure than would

be expected.
waterbrash Sudden filling of the mouth with dilute saliva.
water chestnut Seeds of Trapa natans and T. bicornis; see
chestnut.
watercress Leaves of Nasturtium officinale (green watercress,
remains green in autumn and is susceptible to frost) and N.
microphyllum × officinale (brown or winter watercress); eaten
raw in salads.
Composition/100g: (edible portion 92%) water 95g, 46kJ
(11kcal), protein 2.3g, fat 0.1g, carbohydrate 1.3g (0.2 g sugars),
fibre 0.5g, ash 1.2g, Ca 120mg, Fe 0.2mg, Mg 21mg, P 60mg, K
330mg, Na 41mg, Zn 0.1mg, Cu 0.1mg, Mn 0.2mg, Se 0.9µg,
vitamin A 235µg RE (8587µg carotenoids), E 1mg, K 250mg, B
1
0.09mg, B
2
0.12mg, niacin 0.2mg, B
6
0.13mg, folate 9µg, pan-
tothenate 0.3mg, C 43mg. A 20g serving (quarter bunch) is a
source of vitamin C.
506
water, demineralised Water that has been purified by passage
through a bed of ion-exchange resin or treatment by reverse
osmosis (see osmosis,reverse),which removes mineral salts.Dem-
ineralised or deionised water is at least as pure as distilled water.
See also water, remineralised.
water, extracellular, intracellular See water balance.
water-glass Sodium silicate; used at one time to preserve eggs, by
forming a layer of insoluble calcium silicate around the shell, so

sealing the pores.
water hardness Soap-precipitating power of water due to the for-
mation of insoluble calcium and magnesium salts of the soap.
Temporary hardness (carbonates) is removed by boiling, perma-
nent hardness (sulphates) is not. May be measured in degrees
Clarke; one degree = 10ppm calcium carbonate.
water holding capacity See meat, water holding capacity.
water ice See sorbet.
water lemon See passion fruit.
waterless cooking Cooking in a heavy pan with tightly fitting lid,
with a steam vent; only a minimal amount of cooking liquid is
needed, but the food is not cooked under pressure.
Waterlow classification A system for classifying protein–energy
malnutrition in children based on wasting (the percentage of
expected weight for height) and the degree of stunting (the per-
centage of expected height for age).
See also gomez classification; wellcome classification.
watermelon Fruit of Citrullus vulgaris.
Composition/100g: (edible portion 52%) water 91g, 126kJ
(30kcal), protein 0.6g, fat 0.2g, carbohydrate 7.6g (6.2 g sugars),
fibre 0.4g, ash 0.3g, Ca 7mg, Fe 0.2mg, Mg 10mg, P 11mg, K
112mg, Na 1mg, Zn 0.1mg, Se 0.4µg, vitamin A 28µg RE
(4921µg carotenoids), E 0.1 mg, K 0.1mg, B
1
0.03mg, B
2
0.02mg,
niacin 0.2mg, B
6
0.05mg, folate 3µg, pantothenate 0.2mg, C 8mg.

A 120g serving is a source of vitamin C.
water, metabolic Produced in the body by the oxidation of foods.
100g of fat produces 107.1g, 100g of starch produces 55.1g and
100g of protein produces 41.3g of water.
See also water balance.
water, mineral Natural, untreated, spring waters, some of which
are naturally carbonated, may be slightly alkaline or salty.
Numerous health claims have been made for the benefits arising
from the traces of a large number of minerals found in solution.
They are normally named after the town nearest the source.
Examples are Evian, Malvern, Apollinaris, Vichy, Vittel, Perrier.
Sparkling mineral water may either contain the gases naturally
present at the source or may be artificially carbonated (soda
507
water, Seltzer water or club soda). Carbonated beverages are
sometimes called minerals.
water, remineralised Bottled water that has been demineralised
(see water, demineralised) by reverse osmosis (see osmosis,
reverse), then had specific minerals added.
waxes esters of fatty acids with long-chain monohydric alcohols
(fats are esters of fatty acids with the trihydric alcohol glycerol).
For example, beeswax, myricyl palmitate; spermaceti, cetyl
palmitate. Animal waxes are often esters of the steroid alcohol
cholesterol.
waxing Coating fruits and vegetables with a thin layer of edible
wax. In the case of apples and oranges this replaces the natural
wax that is removed when the crop is washed; in the case of
vegetables it is an addition; in both instances the waxing
prevents loss of moisture, prolongs storage life and improves the
appearance.

waxy flour Flour prepared from varieties of rice and maize that
have starch with waxy adhesive properties,and acts as a stabiliser
in sauces.
See also cornflour.
WBC See meat, water binding capacity.
WCRF World Cancer Research Fund, an international alliance
of organisations dedicated to the prevention and control of
cancer through healthy diets and lifestyles. Web site http://www.
wcrf.org/.
weaning foods Foods specially formulated for infants aged
between 3 and 9 months for the transition between breast or
bottle feeding and normal intake of solid foods.
Weende analysis See proximate analysis.
weenie American name for small sausages, abbreviation of
wienerwurst.
weight, desirable (ideal) Standardised tables of desirable (or
ideal) weight for height for adults are based on life expectancy;
both undernutrition and obesity are associated with increased
risk of premature death.
See also body mass index.
weight-for-age An index of the adequacy of the child’s nutrition
to support growth. Standard weight-for-age is the 50th centile of
the weight-for-age curves of well-fed children.
See also anthropometry; nchs standards.
weight-for-height For children, can be used as an alternative to
weight-for-age as an index of nutritional adequacy; for adults it
is the only acceptable way of expressing weight relative to ideal
or desirable weight.
See also anthropometry; body mass index; nchs standards;
weight, desirable.

508
weighting oils See brominated oils.
weisse See beer.
Wellcome classification A system for classifying protein–energy
malnutrition in children based on percentage of expected
weight for age and the presence or absence of oedema.
Between 60 and 80% of expected weight is underweight in the
absence of oedema, and is kwashiorkor if oedema is present;
under 60% of expected weight is marasmus in the absence
of oedema, and is marasmic kwashiorkor if oedema is
present.
See also gomez classification; waterlow classification.
Welsh rarebit (Originally rabbit); melted cheese, mixed with
mustard powder, pepper and brown ale, served on toast. Buck
rarebit is Welsh rarebit topped with a poached egg.
Wensleydale English hard cheese, originally made from sheep or
goat milk, now cow milk; may be blue veined.
Wernicke–Korsakoff syndrome The result of brain damage due
to vitamin b
1
deficiency,commonly associated with alcohol abuse.
Affected subjects show clear signs of neurological damage,
including nystagmus with psychiatric changes (korsakoff’s
psychosis) characterised by loss of recent memory and confab-
ulation, the invention of fabulous stories.
See also alcoholism; beriberi.
Wesson oil Cottonseed oil deodorised by a high temperature
vacuum process developed by David Wesson in 1899.
western blot See blotting.
wet bulb temperature Temperature measured by a wet ther-

mometer in an air–water vapour mixture, as a means of deter-
mining humidity.
wettability The ability of a powder to absorb water and start the
process of reconstituting a dried material.
Wetzel Grid Children are grouped by physique into five groups,
ranging from tall and thin to short and thick-set. A healthy child
will grow, as measured by height and weight, along one of these
channels at a standard rate, if s/he deviates from the channel,
malnutrition is suspected.
See also anthropometry; weight-for-age; weight-for-height.
wey Obsolete measure; 48 bushels of oats or 40 bushels of salt or
corn.
WHC See meat, water holding capacity.
wheat The most important of the cereals and one of the most
widely grown crops. Many thousand varieties are known but
there are three main types: Triticum vulgare, used mainly for
bread; T. durum (durum wheat), largely used for pasta; and T.
compactum (club wheat), too soft for ordinary bread. The berry
is composed of the outer branny husk, 13% of the grain,the germ
509