FOODS UNDER THE MICROSCOPEUpdated: February 2, 2009.New !"#r$at#!.I!tr#du%t#!M%r#&%#py & a &%e!t"% d&%p'!e, t(e #b)e%t*e #" w(%( & t# e!'ar+e $!ute part%'e& #r &tru%ture& ! #rder t# &tudy t(e$. Depe!d!+ #! w(et(er t(e #b)e%t& are b#'#+%a', +e#'#+%a', #r$eta''ur+%a', t(ere & a wde *arety #" !&tru$e!t& a!d te%(!,ue& &utab'e t# a%(e*e t(e #b)e%t*e. - +##d &tart!+ p#!t #! t(e I!ter!et & t(e M%r#&%#py ! ./peda.T(ere are $a!y rea!& t# e0a$!e "##d& u!der a $%r#&%#pe. 1#w2$a+!"%at#! d&&e%t!+ $%r#&%#pe& "u!%t#! a& $a+!"y!+ +'a&&e& a!d $ay be u&ed "#r better *ew& #" t(e "##d &tru%ture. T(ey &(#w deta'& #" $eat "bre& #r &eed &ur"a%e& a!d &p%e& w(%( $ay be %aptured #!"'$ #r a *de# tape u&!+ *ar#u& atta%($e!t&. T(ey are t(e "r&t $%r#&%#pe& t# be u&ed w(e! e0a$!!+ a part%u'ate "##d %#!ta$!a!t.M%r#&%#py at a (+(er re'ut#! (e'p& t# u!der&ta!d w(at (appe!& t# t(e #r+!a' b#'#+%a'$atera'& &u%( a& +ra!&, $u&%'e&, #r $'/ w(e! t(ey are pr#%e&&ed !t# bread #r pa&ta, (a$ #r &tea/, y#+urt #r %(ee&e. .t( !du&tra' "##d pr#du%t#!, de*e'#per& #" !ew "##d& !eed t# /!#w w(at %au&e& a part%u'ar "##d t# be e'a&t% #r &preadab'e 3e.+.: &tr!+ %(ee&e a!d pr#%e&&ed %(ee&e4 #r w(y $e "##d&, w(%( are &$##t( u!der !#r$a' %#!dt#!&, be%#$e +rtty 3e.+.: %e %rea$ &t#red "#r t## '#!+ ! a "ree5er4.Opt%a' $%r#&%#pe& pr#*de a (+(er re'ut#! t(a! d&&e%t!+ $%r#&%#pe& a!d #pe! %#$p'ete'y !ew *ew& at t(e &pe%$e!& e0a$!ed. T(ey are re'at*e'y ea&y t# u&e. T(er pr%e $a/e& t(e$ a""#rdab'e t# a!y 'ab#rat#ry 2 e*e! !d*dua' e!t(u&a&t& a!d &tude!t&. Ma+!"%at#!& up t# 20000 are a%(e*ed u&!+ t(& /!d #" $%r#&%#pe&. .t( a (+(er $a+!"%at#!, +reater deta'& are re*ea'ed but &$a''er area& are &(#w!. I! addt#! t# &tru%tura' deta'& &u%( a& +'#bu'e& #r "bre&, &pe%"% &ta!!+ pr#%edure& $a/e t p#&&b'e t# d&t!+u&( pr#te!& "r#$ "at&, &tar%(, %e''u'#&e, $!era' %#$p#!e!t& et%. - b##/ e!tt'ed F##d M%r#&%#py by O'+a F'!t 3R#ya' M%r#&%#p%a' S#%ety M%r#&%#py Ha!db##/ 60, 7#& S%e!t"% Pub'&(er&, O0"#rd, U8 999:4 pre&e!t& !&tru%t#!& #! "##d &a$p'e preparat#! "#r $%r#&%#py a!d (e'p& t# !terpret t(e re&u't&. It & ''u&trated wt( $a!y $%r#+rap(&.E'e%tr#! $%r#&%#pe& are t(e &ub)e%t #" t(& &te. T(ey pr#*de a %#!&derab'y (+(er re'ut#! t(a! '+(t 3#pt%a'4 $%r#&%#pe&. H#we*er, &!%e e'e%tr#!&, a!d !#t p(#t#!&, are u&ed t# e!'ar+e t(e *ew& #" t(e &pe%$e!&, t(e re&u't!+ p(#t#+rap(& 3$%r#+rap(&4 are b'a%/ a!d w(te #!'y. F#r edu%at#! a!d ''u&trat#! purp#&e&, !d*dua' &pe%$e! %#$p#!e!t& &u%( a& &tar%( +ra!u'e&, "at +'#bu'e&, $u&%'e "bre&, %e'' wa''&, $%r##r+a!&$& et%. ! &u%( $%r#+rap(& $ay be (+('+(ted by "a'&e %#'#ur&. E'e%tr#! $%r#&%#py pr#*de& a $ar/ed'y (+(er $a+!"%at#! at a %#!&derab'y better re'ut#! t(a! '+(t $%r#&%#py but & $u%( $#re e0pe!&*e t# per"#r$. I!&tead #" '+(t, a bea$#" e'e%tr#!& +e!erated "r#$ a! !%a!de&%e!t tu!+&te! #r 'a!t(a!u$ (e0ab#rde 31a7;4 e'e%tr#de & u&ed t# $a+!"y t(e $a+e #" t(e &a$p'e. T(e e'e%tr#!& are !e+at*e'y %(ar+ed part%'e& w(%( be(a*e '/e radat#! (a*!+ a *ery &(#rt wa*e'e!+t(. T(ere are tw# $a)#r e'e%tr#! $%r#&%#py $#de& 2 &%a!!!+ e'e%tr#! $%r#&%#py 3SEM4 a!d tra!&$&! e'e%tr#! $%r#&%#py 3TEM4. T(ee'e%tr#! bea$ & "#%u&&ed u&!+ $a+!et% 'e!&e& ! b#t( /!d& #" $%r#&%#pe. I! t(e &%(e$at% da+ra$ #! t(e 'e"t, < 'e!&e& are &(#w! "#r TEM a!d #!'y tw# "#r SEM. T(e &pe%$e! ! p'a%ed !t# t(e pat( #" t(e e'e%tr#! bea$ 3S4 ! t(e TEM but ! t(e SEM t & p'a%ed at t(e e!d #" t(e "#%u&&ed e'e%tr#! bea$ pat(. T(e $a+e 3I$4 & pr#du%ed ! t(e "#r$ #" a &(ad#w #! a "'u#re&%e!t &%ree! ! TEM. =reater deta' #! $a+e "#r$at#! ! t(e TEM & a' a*a'ab'e. I! SEM, re"'e%ted a!d &e%#!dary e'e%tr#!& are pr#%e&&ed by a! e'e%tr#! dete%t#r t# "#r$ a ,ua& t(ree2d$e!!a' $a+e #! a $#!t#r &%ree!. S!%e t(e e'e%tr#!& w#u'd be ea&'y abrbed by ar, t(e $%r#&%#p% e0a$!at#! & %arred #ut ! *a%u#. T# e!&ure t(at t(e e'e%tr#!& w'' pe!etrate a t(! &e%t#! #" t(e &pe%$e! #r t& rep'%a, t(e e'e%tr#! bea$ & a%%e'erated ! t(e $%r#&%#pe. -! a!#de wt( a! #r"%e ! t& %e!tre & p#&t*e'y %(ar+ed. T(e !e+at*e e'e%tr#!& ru&( t#ward t a!d t(#&e w(%( are ! t(e %e!tre "'y, a%%e'erated, t(r#u+( t(e #r"%e t#ward t(e &pe%$e!. -%%e'erat!+ *#'ta+e #" 6 t# 20 /> (a& bee!u&ed t# d# SEM a!d ;0 t# ?0 /> (a*e bee! u&ed ! TEM #" "##d&.E!*r#!$e!ta' &%a!!!+ e'e%tr#! $%r#&%#pe& 3ESEM4 %a! be u&ed t# e0a$!e (ydrated 3water2%#!ta!!+4 &pe%$e!& at a redu%ed ar pre&&ure. I! t(& way, t(ere & !# !eed t# dry #r "ree5e t(e &pe%$e!. T(& & part%u'ar'y u&e"u' wt( *ery "ra+'e &pe%$e!& &u%( a& $#u'd& 3"u!+ a!d t(er &p#re&4 a!d p'a!t &pe%$e!& &u%( a& "rut& a!d *e+etab'e&. ESEM $%r#+rap(& (a*e bee! %#!trbuted by Mr. -.2F. @a!+. Tradt#!a' e'e%tr#! $%r#&%#py re,ure& t(at t(e &pe%$e! $u&t !#t re'ea&e a!y +a& #r *ap#ur w(e! !&erted !t# t(e tra!&$&! #r &%a!!!+ e'e%tr#! $%r#&%#pe. E0%ept "#r p#wdered "##d& &u%( a& "'#ur, &u+ar, #r $'/ p#wder, $#&t "##d& %#!ta! water. Dry!+ #r "ree5!+ at a *ery '#w te$perature #" 2900AC e!&ure t(at t(e %#!dt#! #" !#t re'ea&!+ +a& #r *ap#ur & $et.Tra!&$&! e'e%tr#! $%r#&%#py %a! by per"#r$ed u&!+ *ar#u& te%(!,ue&. T(e $#&t %#$$#! %#!&&t& #" e$bedd!+ t(e &pe%$e! ! a re&!, %utt!+ t(! &e%t#!& 39< t# 90 !$ t(%/4 u&!+ a $%r#t#$e, &ta!!+ t(e &tru%ture& wt(! t(e &e%t#!& 3u&!+ (ea*y $eta' &a't& &u%( a& #&$u$, 'ead, a!d ura!u$4, a!d p'a%!+ t(e &e%t#!& !t# t(e pat( #" t(e e'e%tr#! bea$. Ot(er TEM $et(#d& !%'ude !e+at*e &ta!!+, w(%( & a re'at*e'y &$p'e pr#%edure w(ereby $!ute part%'e& &u%( a& %a&e! $%e''e&, detary "bre, ba%ter#p(a+e, #r ba%tera are $0ed wt( a (ea*y $eta' &a't 'ut#! a!d app'ed #! a t(! e'e%tr#!2tra!&pare!t "'$. T(e &pe%$e! a!d t(e &a't 'ut#! are dred a!d p'a%ed !t# t(e $%r#&%#pe. T(e (ea*y $eta', w(%( &urr#u!d& t(e #r+a!% &pe%$e!, abrb& e'e%tr#!& but t(e e'e%tr#!& w(%( pa&& t(r#u+( t(e #r+a!% &pe%$e! "#r$ a B!e+at*e'y &ta!edB $a+e. Meta' &(ad#w!+ & a!#t(er &$p'e te%(!,ue w(ereby t(e &pe%$e! & dred #! a tra!&'u%e!t "'$ a!d t(e! & B&(ad#wedB wt( p'at!u$ *ap#ur ! *a%u#. T(e t(%/!e&& #" t(e %#at!+ 3'e&& t(a! 0.00< $%r#$eter4 depe!d& #! t(e a!+'e #" t(e &ur"a%e &(ad#wed. T(e $a+e & "#r$ed by t(e e'e%tr#! bea$ w(%( pa&&e& t(r#u+( t(e d""ere!t t(%/!e&& #" t(e %#at!+ w(%( depe!d& #! t(e t#p#+rap(y #" t(e &pe%$e!B& &ur"a%e. Free5e2"ra%tur!+ a!d "ree5e2et%(!+ te%(!,ue& are t(e $#&t 'ab#r#u&. T(ey $a/e t p#&&b'e t# e0a$!e t(e &pe%$e! wt(#ut a'ter!+ t %(e$%a''y 3"0at#!4 #r p(y&%a''y 3de(ydrat#!, $pre+!at#! wt( a re&!, dry!+4. T(e &pe%$e! & rapd'y "r#5e!, t(e! & "ree5e2"ra%tured at a te$perature be'#w 2990AC a!d t(e "ra%ture p'a!e & rep'%ated wt( p'at!u$ a!d %arb#! et(er $$edate'y #r a"ter a %erta! per#d #" "ree5e2et%(!+, dur!+ w(%( a t(! 'ayer #"%e ! t(e &pe%$e! &ub'$e& #"" a!d re*ea'& u!der'y!+ &tru%ture&. T(e &pe%$e! & t(awed a!d t(e rep'%a & &eparated "r#$ t(e &pe%$e!, %'ea!ed "r#$ &pe%$e! re&due&, a!d e0a$!ed ! t(e $%r#&%#pe.I! &%a!!!+ e'e%tr#! $%r#&%#py 3SEM4, t(e &pe%$e! & e0a$!ed by a "#%u&&ed e'e%tr#! bea$. S#$e #" t(e&e e'e%tr#!& are re"'e%ted a!d #t(er& +e!erate& &e%#!dary e'e%tr#! "r#$ t(e +#'d %#at!+. 3- +reat *arety #" #t(er !tera%t#!& a' ta/e& p'a%e4. Se%#!dary e'e%tr#!& 3#r, ! #t(er app'%at#!&, ba%/&%attered e'e%tr#!&4 are u&ed t# "#r$ a! e!'ar+ed $a+e #" t(e &pe%$e! &ur"a%e. T(e !%de!t e'e%tr#!& %arry a !e+at*e %(ar+e a!d ! #rder t# be B!eutra'5edB a"ter t(ey (a*e %#$p'eted t(e e0a$!at#!, t(e &pe%$e! &(#u'd be e'e%tr%a''y %#!du%t*e. T(& & a%(e*ed et(er by %(e$%a' pr#%edure& w(%( $pre+!ate t(e &pe%$e! wt( #&$u$ #r, $#re "re,ue!t'y, by p(y&%a''y %#at!+ t& wt( +#'d, a +#'d2pa''adu$, p'at!u$, #r rdu$ 2 #%%a!a''y b#t( pr#%edure& are %#$b!ed. Meta' %#at!+ pr#*de& a pat( "#r t(e e'e%tr#!&. I" t(& pat( & !terrupted 3by !%#$p'ete $eta' %#at!+ #r by %ra%/&4, t(e e'e%tr#!& &t ! t(e area t(u& 'ated a!d repe' a!y e'e%tr#!& ! t(e !%de!ta' bea$ ! a%%#rda!%e wt( t(e ru'e t(at e'e%tr%a''y %(ar+ed part%'e& #" t(e &a$e %(ar+e repe' ea%( #t(er. T(u& t(e area #%%uped by t(e &tat#!ary !e+at*e %(ar+e & by2pa&&ed a!d %a!!#t be e0a$!ed. .(te &p#t& #r '!e& de*e'#p ! &u%( p'a%e& a!d t(e $a+e & %(ara%ter5ed a& &u""er!+ "r#$ %(ar+!+ art"a%t&.SEM &(#w& &pe%$e! &ur"a%e&. T# t(e u!!tated, &u%( $a+e& $ay appear "a$'ar, &!%e t(& & t(e way ! w(%( we per%e*e #ur e!*r#!$e!t, w(ere we a' &ee &ur"a%e&, "#r e0a$p'e, $'/ p#wder part%'e&. T(e $a+e& are #b&er*ed #! a $#!t#r a!d p(#t#+rap(ed u&!+ a 6e'/y I -, 8a'Hb M: E!%ap&u'at#! #" *&%#u& (+(2"at "##d& ! %a'%u$ a'+!ate +e' tube& at a$be!t te$perature. F##d Stru%ture 9, 9ar#u& rapd "ree5!+ pr#%edure&, part%u'ar'y (+(2pre&&ure "ree5!+, (a*e a' bee! de*e'#ped 2 deta'& $ay be "#u!d ! b##/& '&ted at t(e e!d #" t(& &e%t#! 2 ! "a%t, at pre&e!t, t(e pr!%p'e& a!d app'%at#!& &ee$ t# be better e0p'a!ed ! t(e #'der b##/& t(a! #! t(e .eb4. Ne+at*e &ta!!+ #" !"'ue!5a *ru& wt( a$$#!u$ $#'ybdate by M. Ner$ut F2G:T#p: Spe%$e! "ree5e2dred7#tt#$: Spe%$e! ar2dred7ar& !d%ate 0.9 O$ Fr#5e! &pe%$e!& are u&ua''y "ree5e2"ra%tured ! #rder t# e0a$!e t(e !ter!a' &tru%ture by SEM. Free5e "ra%tur!+ $ay be d#!e ! a &pe%a' apparatu& %a''ed t(e %ry#2&ta+e, atta%(ed t# t(e &%a!!!+ e'e%tr#! $%r#&%#pe. - bre" per#d #" "ree5e et%(!+ re$#*e& a t(! 'ayer #" t(e "r#5e! %e by &ub'$at#! t(u& a''#w!+ t(e 'd &tru%ture& t# e$er+e. T(e "r#5e! &pe%$e! & t(e! %#ated wt( +#'d. Free5e "ra%tur!+ $ay be %#$b!ed wt( %#!*e!t#!a' SEM. T(e &pe%$e! & %(e$%a''y "0ed, de(ydrated ! ab'ute et(a!#', "r#5e! a!d "ree5e2"ra%tured ! ',ud !tr#+e! 3et(a!#' d#e&!#t pr#du%e %ry&ta'& w(e! "r#5e!4. T(e "ra+$e!t& are t(awed ! ab'ute et(a!#', %rt%a'2p#!t dred, $#u!ted #! SEM &tub&, %#ated wt( +#'d, a!d e0a$!ed by %#!*e!t#!a' SEM. T(e be!e"t& #" t(& pr#%edure (a*e bee! #ut'!ed &e*era' para+rap(& be'#w a!d e'&ew(ere. Spe%$e!& de&t!ed "#r TEM $ay #r $ay !#t be "ree5e2et%(ed a!d t(e! rep'%ated wt( p'at!u$ a!d %arb#!. T(e &pe%$e! & t(e! re$#*ed a!d t(e rep'%a & %'ea!ed, %aptured #! a +rd, a!d e0a$!ed. Free5!+ & a' ad*a!ta+e#u& t# !e+at*e &ta!!+ #" $e &pe%$e!&. -r2dry!+ u&ed $#&t "re,ue!t'y d&t#rt& e*e! $!ute part%'e& &u%( a& &p(er%a' *ru&e&. Free5!+ t(e$ wt( t(e t(! 'ayer #" t(e !e+at*e &ta! &t'' #! t(e &upp#rt!+ "'$ a!d "ree5e2dry!+ pre&er*e& t(e +'#bu'ar &(ape& #" t(e *ru&e& a& (ad bee! &(#w! by M. Ner$ut ! F2G. Free5e2dry!+ & &$'ar'y u&e"u' wt( &pe%$e!& de&t!ed "#r $eta' &(ad#w!+ a& (ad a' bee! &(#w! by t(e &a$e aut(#r. T(e&e pr#%edure& w#u'd be u&e"u' wt( %a&e! $%e''e& a!d #t(er $!ute (ydrated %#rpu&%u'ar "##d %#$p#!e!t&.C#u'd "r#5e! %e %rea$ be e$bedded ! a re&!M H. D. =#"" pr#*de& t(e a!&wer a!d de%rbe& a! $p#rta!t preparat#ry pr#%edure %a''ed "ree5e &ub&ttut#!.I!"#r$at#! ! +reater deta' $ay be "#u!d ! t(e&e a!d #t(er b##/&:9. E'e%tr#! $%r#&%#py #" "##d& M. 8a'ab !: P(y&%a' Pr#perte& #" F##d&, M. Pe'e+ a!d E. 7. 7a+'ey 3ed&.4, pp. :6290:, ->I Pub'. C#., I!%., .e&tp#rt, CT, US-, 99?6.2. Free5e2Et%(!+ Te%(!,ue& a!d -pp'%at#!& E. 1. 7e!edett a!d P. Fa*ard 3ed&.4, 2D: pp., S#%QtQ Fra!Ra&e de M%r#&%#pe S'e%tr#!,ue, Par&, Fra!%e, 99D6.6. Free5e "ra%ture: Met(#d&, -rt"a%t&, a!d I!terpretat#!& K. E. Ra&( a!d C. S. Hud! 3ed&.4, 20: pp., Ra*e! Pre&&, New @#r/, US-. 99D9.:. Free5e2Fra%ture Rep'%at#! #" 7#'#+%a' T&&ue& C. St#'!&/ a!d -. S. 7reat(!a%(, 9D6 pp., -%ade$% Pre&&, 99Drtua' 1brary: M%r#&%#py pr#*de& '!/& t# *ar#u& te%(!,ue&, e,up$e!t &upp'er& et%. Y -!#t(er &te e0p'a!& *ar#u& /!d& #" $%r#&%#py a!d re"er& t(e reader& t# *ar#u& &upp'er&. Y 1!/& t# *ar#u& $%r#&%#py &te&.Y 1!/& t# *ar#u& &%e!t"% 'brare&.Su++e&t#!& "#r aut(#r& #" &%e!t"% rep#rt& a!d $a!u&%rpt& w(%( $ay $pr#*e t(er wrt!+ &/''& are pr#*ded at a!#t(er .eb &te.MI18M'/ a!d It& C#!&ttue!t&FOODS UNDER THE MICROSCOPEE*eryb#dy /!#w& t(at $'/ & ',ud. 7ut w(y & t #pa,ue a!d w(teM Or d#e& t (a*e a ye''#w&( t!tM .(y a!d w(e! d#e& t %urd'eM .(at & a%tua''y %urd'!+M I" y#+urt a!d %(ee&e areb#t( $ade "r#$ $'/, w(y are t(ey d""ere!t "r#$ ea%( #t(erM I& t true t(at t(ere are ba%tera ! b#t( y#+urt a!d %(ee&eM .(y are t(ey t(ereM -!&wer& t# t(e&e ,ue&t#!& $ay a'ready be "#u!d #! t(e I!ter!et.M'/ & pr#du%ed by a'' $a$$a' "e$a'e& t# "eed t(er !ewb#r!& a!d t(e ',ud "#r$ & $#&t %#!*e!e!t. T(& $ea!& t(at t(e %#!%e!trat#! #" !utre!t& & re'at*e'y '#w %#$pared t# "##d& %#!&u$ed by adu't&. C#w $'/ %#!ta!& 6 t# :E pr#te!, : t# :.