Encyclopedia of Food Sciences and Nutrition, Ten-Volume Set, Second Edition

6406 Pages·2003·85.54 MB·English

by  Benjamin Caballero

EDITOR-IN-CHIEF
BenjaminCaballero
JohnsHopkinsUniversity
CenterforHumanNutrition
SchoolofHygieneandPublicHealth
615NorthWolfeStreet
Baltimore,Maryland21205-2179
USA
EDITORIAL ADVISORY BOARD
EDITORS
LuizCTrugo
LaboratoryofFoodandNutritionBiochemistry
DepartmentofBiochemistry,InstituteofChemistry
FederalUniversityofRiodeJaneiro
CTBlocoALab528-A
IlhadoFundao,21949-900RiodeJaneiro
Brazil
PaulMFinglas
InstituteofFoodResearch
NorwichLaboratory
ColneyLane
Norwich,NR47UA
UK
PeterBelton PeterBerryOttaway
AFRCInstituteofFoodResearch BerryOttawayAssociatesLtd
NorwichLaboratory 1AFieldsYard
ColneyLane PloughLane
NorwichNR47UA HerefordHR40EL
UK UK
vi EDITORIALADVISORYBOARD
RicardoBressani GeorgeDHill
UniversidaddelValledeGuatemala LincolnUniversity
InstitutedeInvestigaciones PlantSciencesGroup
Aparto82 FieldServiceCentre
Guatemala01901 Soil,PlantandEcologicalSciencesDivision
POBox84
Canterbury
BarbaraBurlingame
NewZealand
FoodandAgricultureOrganizationoftheUnitedNations
VialedelleTermediCaracalla
HarveyEIndyk
Rome00100
AnchorProductsLimited
Italy
POBox7
Waitoa
JerryCash NewZealand
MichiganStateUniversity
DepartmentofFoodScienceandHumanNutrition AnuraKurpad
EastLansing StJohn’sMedicalSchool
MI48824 DepartmentofNutrition
USA Bangalore
India
ColinDennis
JimFLawrence
Campden&ChorleywoodRoodResearchAssociation
SirFGBantingResearchCentre,Tunney’sPasture
ChippingCampden
HealthandWelfareCanada,HealthProtectionBranch
GloucestershireGL556LD
Ottawa
UK
OntarioK1A0L2
Canada
JohannaTDwyer
TuftsUniversity
FXavierMalcata
USDAHumanNutritionResearchCenter
UniversidadeCatolicaPortugesa
711WashingtonStreet
EscolaSuperiordeBiotecnologia
USA
RuaDrAntonioBernardinodeAlmeida
TeeE-Siong Porto4200
InstituteofMedicalResearch Portugal
DivisionofHumanNutrition
JalanPahang KeshavanNiranjan
KualaLumpur50588 UniversityofReading
Malaysia DepartmentofFoodScienceandTechnology
Whiteknights
PatrickFFox POBox226
UniversityCollege Reading
DepartmentofFoodChemistry BerkshireRG62AP
Cork UK
RepublicofIreland
JohnRPiggott
JesseGregory
UniversityofStrathclyde
UniversityofFlorida
DepartmentofBioscienceandBiotechnology
FoodScienceandHumanNutritionDepartment
204GeorgeStreet
POBox110370
Glasgow
NewellDrive
ScotlandG11XW
Gainesville
UK
FL32611-0370
USA
VienoPiironen
RJHamilton UniversityofHelsinki
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Formby POBox27
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UK Finland
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JanPokorny SteveLTaylor
PragueInstituteofChemicalTechnology UniversityofNebraskaLincoln
DepartmentofFoodScience DepartmentofFoodScienceandTechnology
TechnickaStreet5 143HCFilleyHall
CZ-16628Prague6 EastCampus
CzechRepublic Lincoln
NE68583-0919
USA
TerryARoberts
59EdenhamCrescent JeanWoo
Reading ChineseUniversityofHongKong
BerkshireRG26HU DepartmentofMedicine
UK PrinceofWalesHospital
Shatin
N.T
De´liaBRodriguez-Amaya HongKong
UniversityofCampinas
DepartmentofFoodScience DavidCWoollard
FacultyofFoodEngineering AgriQualityNZLtd
POBox6121 LynfieldFoodServicesCentre
Campinas 131BoundaryRoad
SP13081-970 POBox41
Brazil Auckland1
NewZealand
JacquesPRoozen StevenZeisel
WageningenUniversity UniversityofNorthCarolinaatChapelHill
AgrotechnologyandFoodSciences DepartmentofNutrition
LaboratoryofFoodChemistry 2212McGavran-GreenbergHall
POBox8129 ChapelHill
6700EVWageningen NC27599-7400
TheNetherlands USA
FOREWORD
Therearenodisciplinessoall-encompassinginhumanendeavoursasfoodscienceandnutrition.Whetheritbe
biological, chemical, clinical, environmental, agricultural,physical– every science has a role and an impact.
However, the disciplines of food science and nutrition do not begin or end with science. Politics and ethics,
business and trade, humanitarian efforts, law and order, and basic human rights and morality all have
somethingtodowithittoo.
Asdisciplines,foodscienceandnutritionanswerquestionsandsolveproblems.Thequestionsandproblems
arediverse,andcoverthefullspectrumofeveryissue.Lifespanisonesuchissue,coveredfromthenutritional
basisforfetalandinfantdevelopment,tooptimalnutritionfortheelderly.Anothersuchissueisthetimespan
of the ancient and wild agro-biodiversity that we are working to preserve, to the designer cultivars from
biotechnology that we are trying to develop. Still another is the age-old food preparation methods now
honoured by the ‘eco-gastronomes’ of the world, to the high tech food product development advances of
recentyears.
As with most endeavours, our scientific and technological solutions can and do create new, unforeseen
problems. The technologies that gave us an affordable and abundantfoodsupplyled toobesityand chronic
diseases.The‘‘greenrevolution’’ledtolossofsomeimportantagro-biodiversity.Thetechnologicalinnovation
that gave us stable fats through hydrogenation, flooded the food supply with trans fatty acids. All these
problems were identified through a multidisciplinary scientific approach and solutions are known. When
technology created the problem and technology has found the solution, implementation is usually more
successful.Reducingtransfattyacidsinthefoodsupplyiscaseinpoint.Beyondthetechnologies,thesolutions
are more difficult to implement. We know how obesity can be reduced, but the solution is not directly
technological.Hence,weshownosuccessintheendeavour.
Ofalltheproblemsstillconfoundingusinfoodscienceandnutrition,noneissocompellingasreducingthe
number of hungry people in the world. FAO estimates that there are 800 million people who do not have
enough to eat. The World Food Summit Plan of Action, the Millennium Development Goals and other
internationaleffortslook tofood science and nutrition toprovide thesolution. Yetwe only havepartof the
solution—the science part. The wider world of effort in food science and nutrition needs to be more
conscientiously addressed by scientists. This is the world of advocacy and action: advocacy for food and
nutritionasbasichumanrights,coupledwithactiontogetfoodwhereitisneeded.
Butallthoseeffortswouldbefutileiftheyarenotbasedonsoundscientificinformation.Thatiswhyworks
such as this Encyclopedia are so important. They provide to a wide readership, scientists and non-scientists
alike, the opportunity to quickly gain understanding on specific topics, to clarify questions, and to orient to
furtherreading.Itisapleasuretobeinvolvedinsuchanendeavour,whereexpertsarewillingtoimparttheir
knowledgeandinsightsonscientificconsensusandonexplorationofcurrentcontroversies.Allthewhile,this
givesusoptimismforabrighterfoodandnutritionfuture.
BarbaraBurlingame
25February2003
INTRODUCTION
Thereisnofactormorevitaltohumansurvivalthanfood.Theonlysourceofmetabolicenergythathumans
canprocessisfromnutrientsandbioactivecompoundswithputativehealthbenefits,andthesecomefromthe
food that we eat. While infectious diseases and natural toxins may or may not affect people, everyone is
inevitablyaffectedbythetypeoffoodtheyconsume.
Inevolutionaryterms,humanshaveincreasedthecomplexityoftheirfoodchaintoanastoundinglevelina
relativelyshorttime.Fromthefewstaplesofsomethousandyearsago,wehavemovedtoanextraordinarily
richfoodchain,withmanyfooditemsthatwouldhavebeenunrecognizablejustsomehundredyearsago.
In this evolution, scientific discovery and technical developments have always gone hand in hand. The
identification of vitamins and other essential nutrients last century, and the development of appropriate
technologies,ledtofoodfortification,andthusforthefirsttimehumanswereabletomodifyfoodstobetter
fulfill their specific needs. As a result, nutritional deficiencies have been reduced dramatically or even
eradicated in many parts of the world. This evolution is also yielding some undesirable consequences. The
abundanceofhigh-density,cheapcaloriesources,andthemarketcompetitionhasfacilitatedoverconsumption
andpromotedobesity,aproblemofglobalproportions.
As the food chain grows in complexity, so does the scientific information related to it. Thus, providing
accurate and integral scientific information on all aspects of the food chain, from agriculture and plant
physiologytodietetics,clinicalnutrition,epidemiology,andpolicyisobviouslyamajorchallenge.
The editors of the first edition of this encyclopedia took that challenge with, we believe, a great deal of
success. This second edition builds on that success while updating and expanding in several areas. A large
numberofentrieshavebeenrevised,andnewentriesadded,amountingtotwoadditionalvolumes.Thesenew
entries include new developments and technologies in food science, emerging issues in nutrition, and addi-
tionalcoverageofkeyareas.Asalways,wehavemadeeffortstopresenttheinformationinaconciseandeasy
toreadformat,whilemaintainingrigorousscientificquality.
We trust that a wide range of scientists and health professionals will find this work useful. From food
scientistsin search of a methodological detail,to policymakers seeking updateon a nutrition issue, we hope
that you will find useful material for your work in this book. We also hope that, in however small way, the
Encyclopedia will be a valuable resource for our shared efforts to improve food quality, availability, access,
andultimately,thehealthofpopulationsaroundtheworld.
BenjaminCaballero
LuizTrugo
PaulFinglas
A
Acceptability of Food SeeFoodAcceptability:AffectiveMethods;MarketResearchMethods
ACESULFAME/ACESULPHAME
JFLawrence,HealthandWelfareCanada,Ontario, Production and Physical and Chemical
Canada Properties
Copyright2003,ElsevierScienceLtd.AllRightsReserved.
Acesulfame K (Figure 1) is structurally related to
0003
saccharin. Italso has many of the same physicaland
chemicalproperties.
Background
Acesulfame was one of a series of sweet-tasting
0004
Acesulfame K (potassium salt of 6-methyl-1,2,3- substances synthesized by Hoechst AG in the late
0001
oxathiazine-4(3H)-one-2,2-dioxide; Figure 1) is a 1960s.Allofthesehadincommontheoxathiazinone
high-intensity artificial sweetener which is about dioxide ring structure. The synthesis involved reac-
200 times as sweet as sucrose (compared to a 3% tionoffluorosulfonylisocyanatewitheitheracetylene
aqueous sucrose solution). It was accidentally dis- derivativesorwithactivemethylenecompoundssuch
covered in 1967 by Dr. Karl Clauss, a researcher as a-diketones, a-keto acids, or esters. The latter re-
with Hoechst AG in Frankfurt, FRG, during his ex- action is used for the commercial production of ace-
periments on new materials research. The sweetener sulfame K. A generalized reaction scheme for
isnotmetabolizedbythehumanbodyandthuscon- synthesis of the oxathiazinone dioxide ring structure
tributesnoenergytothediet.Itisnowapproved for is shown in Figure 2. Many analoges have been pre-
useinmorethan20countries. pared and evaluated for taste properties. The potas-
sium salt of the 6-methyl derivative, acesulfame K,
displayedthebestsensoryandphysicalpropertiesand
Sweetness
thus it has received extensive testing aimed at
ThesweetnesspropertiesofacesulfameKaresimilar obtainingapprovalforitsuseindietfoods.
0002
tosaccharin.Ithasaclean,sharp,sweettastewitha AcesulfameKisawhitecrystallinematerialwhich
0005
rapidonsetofsweetnessandnolingeringaftertasteat isstableupto250(cid:1)C,atwhichtemperatureitdecom-
normal use levels. However, at high concentrations, poses. The free acid form of the sweetener has a
equivalent to 5% or 6% sucrose solutions, acesul- distinctmeltingpointof123.5(cid:1)C.
fame K does possess a bitter, chemical aftertaste. AcesulfameKhasaspecificdensityof1.83.When
0006
The intensity of sweetness of acesulfame K, in dissolved in water it produces a nearly neutral solu-
common with other artificial sweeteners, varies tionwhilethefreeacidisstronglyacidic(pHofa0.1
depending upon its concentration and the type of moll(cid:2)1aqueoussolutionbeing1.15).Thesweetener
foodapplication. Forexample, itis90 times sweeter is very soluble in water; a 27% solution can be
thana6%sucrosesolution,160timessweeterthana prepared at 20(cid:1)C. The solubility of acesulfame K
4%sucrosesolutionand250timessweeterthana2% increases significantly with temperature. At 80(cid:1)C,
sucrose solution. Mixtures of acesulfame K with 50% solutions can be prepared; because of this,
otherintensesweeteners,suchasaspartameorcycla- greater than 99% purity can be obtained by
mate, result in some synergistic increases in sweet- crystallization. It is substantially less soluble in
ness. Mixtures with saccharin are somewhat less common solvents such as ethanol, methanol, or
synergistic. acetone.
2 ACESULFAME/ACESULPHAME
CH Table1 TypicaluselevelsofacesulfameKindietfoods tbl0001
3
Foodproducts Concentration(mgkg(cid:2)1)
O C O
Softdrinks 1000
N− SO Coffeeandtea 267
K+ 2 Jamsandmarmalades 3000
Ready-to-eatdesserts 1000
fig0001 Figure1 StructureofacesulfameK.ReproducedfromAcesul- Chewinggum 2000
phame/Acesulfame, Encyclopaedia of Food Science, Food Tech-
nology and Nutrition, Macrae R, Robinson RK and Sadler MJ
(eds),1993,AcademicPress.
desserts,breakfastcereals,andchewinggum.Table1
lists approximate concentration levels of acesulfame
O O
Ktypicallyusedinseveraltypesoffoods.
∆
C + O O
N
O O O Safety and Regulatory Status
SO F
2 O NH SO2F AcesulfameKhasbeensubjectedtoextensivefeeding 0010
Fluoro- studies in mice, rats, and dogs. The substance is not
sulfonyl- H3C O considered to be carcinogenic, mutagenic, or terato-
isocyanate SO
NaOH 2 genic. It is excreted unmetabolized in test animals
O O
NH or humans. The current maximum acceptable daily
N SO F
2 intake (ADI: the maximum amount that can be con-
H
O
sumed daily for a lifetime without appreciable risk)
established by the Food and Agriculture Organiza-
fig0002 Figure 2 Synthesis of the acesulfame ring structure using
fluorosulfonyl isocyanate and tert-butylacetoacetate as start- tion/World Health Organization (FAO/WHO) Joint
ing materials. Reproduced from Acesulphame/Acesulfame,En- ExpertCommitteeonFoodAdditivesin1990is5mg
cyclopaedia of Food Science, Food Technology and Nutrition, perkgbodyweight.Thisvalueisbasedonthehighest
Macrae R, Robinson RK and Sadler MJ (eds), 1993, Academic
amountfedtoanimalsforwhichtherewasnoeffect.
Press.
ThefirstregulatoryapprovalforacesulfameKwas
0011
bytheUKin1983.Sincethenithasreceivedapproval
forspecificusesinmorethan20countries.
The stability of acesulfame K in the solid state is
0007
verygood.Itcanbestoredatambienttemperaturefor
10 years without decomposition. Aqueous solutions Analysis
at pH 3 or greater may also be stored for extended
Thin-layer chromatography, isotachorphoresis, and
0012
periods without detectable decomposition or loss of
high-performance liquid chromatography (HPLC)
sweetness.However,belowpH3,significanthydroly-
have been evaluated for the determination of ace-
sismayoccuratelevatedtemperatures.Forexample,
sulfame K in a variety of matrices, including liquid
atpH2.5anaqueousbufferedsolutionofacesulfame
and solid food products, animal feed, and biological
Kwoulddecomposebyabout30%after4monthsof
fluids.Ofthethree,HPLCisperhapsthemostuseful
storage at 40(cid:1)C, whereas no decomposition occurs
since the efficiency of the chromatography coupled
under the same conditions within the pH range of
with selective detection (ultraviolet absorbance)
3–8. At 20(cid:1)C, less than 10% decomposition of ace-
enable quantitative measurements to be made in
sulfame K occurs after 4 months’storage at pH 2.5,
rathercomplexfoodsamples.Inaddition,thesample
indicating that under normal storage conditions
preparation is minimal, usually involving a water
aqueoussolutionsofthesweetenerareverystable.
extraction for solid samples or a filtration and dilu-
AcesulfameKisstableundermostfood-processing
0008 tion of liquid samples before direct HPLC analysis.
conditions, including the elevated temperature treat-
Acesulfame K has been incorporated into a multi-
mentsencounteredinpasteurizationandbaking.
sweeteneranalyticalmethodemployingHPLC.
Food Uses Seealso:Carbohydrates:SensoryProperties;
Chromatography:High-performanceLiquid
0009 Becauseofitsstability,acesulfameKhasbeenevalu- Chromatography;GasChromatography;Legislation:
atedinawidevarietyofdietfoodproducts,including ContaminantsandAdulterants;Saccharin;Sweeteners:
table-top sweeteners, soft drinks, fruit preparations, Intensive
ACIDOPHILUSMILK 3
Further Reading reverse-phase liquid chromatography with absorbance
detection. Journal of the Association of Official
FrantaRandBeckB(1986)Alternativestocaneandbeet AnalyticalChemists71:934–937.
sugar.FoodTechnology40:116–128. O’Brien-Nabors L and Gelardi RC (1991) Alternative
KretchmerNandHollenbeckCB(1991)SugarsandSweet- Sweeteners.NewYork:M.Dekker.
eners.BocaRaton:CRCPress.
LawrenceJFandCharbonneauCF(1988)Determinationof
seven artificial sweeteners in diet food preparations by
ACIDOPHILUS MILK
WKneifelandCBonaparte,Universityof derivedfromacido(acid)andphilus(loving)andthis
AgriculturalSciences,Vienna,Austria designationreflectstheacidotolerantpotentialofthis
species. In 1959, Rogosa and Sharpe presented a
Copyright2003,ElsevierScienceLtd.AllRightsReserved.
detaileddescriptionofthisbacterium.
Background and History
Fundamental Characteristics of
Since the first documentation of the beneficial role
0001 Lactobacillusacidophilus
of Lactobacillus acidophilus in correcting disorders
of the human digestive tract in 1922, products con- Together with 43 other species, L. acidophilus is
0004
taining L. acidophilus, especially various types of listed as a member of the genus Lactobacillus which
Acidophilusmilk,havebecomeincreasinglypopular. belongs to the heterogeneous category of lactic acid
Today,amultitudeofsuchproductsarecommercially bacteria. Lactobacilli are Gram-positive, nonmotile,
available,manyofthembeingassignedtothecategory catalase-negative, nonspore-forming rods with vary-
ofprobioticfoods.Mostoftheseprobioticspossessa ingshapes,rangingfromslender,longrodstococco-
bacterial microflora of well-documented and scienti- bacillary forms. They are considered as (facultative)
fically proven bacterial strains with several benefical anaerobes withmicroaerophilicproperties. L.acido-
properties.Besidesothercategoriesoffoodscontain- philus usually appears as rods with rounded ends,
ing special ingredients, these products have also with asize of0.6–0.9(cid:3)1.5–6mm, mainly organized
recently been subclassified under the umbrella of singly or in pairs or short chains (Figure 1). The cell
functionalfoods. wallpeptidoglycanisoftheLys-d-Asptype;themean
Ingeneral,thehumanbodyisinhabitatedbymore proportion of guanine and cytosine in the DNA
0002
than 500 different bacterial species; among them, ranges between 34 and 37%. With rare exceptions,
the lactobacilli play an important ecological role. this bacterium shows good growth at 45(cid:1)C but not
Besidestheirimportantgut-associatedfunction,lacto- below15(cid:1)C,havinganoptimumgrowthtemperature
bacilli are also part of various other human-specific in the range of 35–38(cid:1)C. Substrates with pH values
microbialecosystems,e.g.,skin,vagina,mouth,nasal, of5.5–6.0arepreferred.Metabolically,itisatypical
andconjunctivalsecretions.L.acidophilusisthebest obligatelyhomofermentativebacteriumandproduces
known of the health-promoting lactobacilli of racemiclacticacid(boththelþandthed(cid:2)enantio-
mammals and a naturally resident species of the mericforms)fromlactose,glucose,maltose,sucrose,
humangastrointestinaltract.Itcolonizessegmentsof and other carbohydrates. Usually, it follows the
thelowersmall intestine andpartsofthelargeintes- Embden–Meyerhof–Parnas pathway for glucose
tine, together with other lactobacilli species, such metabolism. Important growth factor requirements
as L. salivarius, L. leichmanii, and L. fermentum. It are acetic or mevalonic acid, riboflavin, pantothenic
isinterestingtonotethattheseresidentLactobacillus acid, niacin, folic acid and calcium, but not cobala-
speciesshouldbedistinguishedfromthespectrumof min, pyridoxine, and thymidine. Starch and cello-
so-called transient Lactobacillus species, which are biose are fermented by most strains. Another
representedbyL.casei. differential key criterion for the distinction from
Historically, in 1900, Australian researchers isol- other lactobacilli (e.g., L. delbrueckii subsp. bulgar-
0003
ated L. acidophilus from fecal samples of bottle-fed icus) is its capability of cleaving esculin. Further
infants for thefirst time and named it ‘Bacillus acid- differential criteria are the utilization of trehalose,
ophilus.’ The actual nomenclature L. acidophilus is melibiose, raffinose, ribose, and lactose. While