Mundt 1 Natalie Mundt Experimental Foods Lab Section 3 October 6, 2014 elatini!ation o" Starc# Lab $eport Purpose
%#e purpose o" t#e &elatini!ation o" starc# laborator' exercise (as to obser)e t#e e""ect o" temperature and added in&redients on starc# &elatini!ation* %#is (as ac#ie)ed usin& )arious starc#es and t#ree separate procedures in (#ic# temperature and added in&redients (ere altered* Line spread and percent sa& tests (ere per"ormed at numerous points durin& t#e experiments to determine t#e e""ect t#at temperature c#an&es and added in&redients #a)e on starc# &elatini!ation* Introduction
Starc#, lon& c#ains o" lin+ed &lucose molecules, is a complex carbo#'drate t#at is made up o" am'lose, t#e linear component o" starc#, and am'lopectin, t#e branc#ed component o" starc# 2-* Some sources o" starc# include corn, (#eat, rice, potato, and tapioca* %#ere are man' "unctional properties o" starc# in coo+in& and ba+in& includin& nutritional )alue, t#ic+enin&, structure, non.en!'matic bro(nin&, emulsi"'in&, retainin& moisture, and "ormin& and stren&t#enin& "ilms, amon& man' ot#er "unctions 2-* %#e starc# "unctions bein& tested in t#ese experiments (ere starc# &elatini!ation and &el "ormation* /n cold (ater starc# &ranules do not#in&, but (#en starc# molecules are #eated in (ater t#e bonds brea+ b rea+ do(n 2-* %#e process o" &elatini!ation t#ic+enin&- occurs (#en starc# is suspended in cold (ater and t#en is continuousl' #eated 2-* "ter &elatini!ation and pastin&, &el "ormation occurs 2-* elatini!ed starc#es can exist in a "lo(in&, pourable "orm as a sol or durin& coolin& t#e paste ma' "orm a &el, a net(or+ (#ere liuid becomes trapped 2-* %o test "or &el "ormation a percent sa& test can
Mundt 2 be per"ormed, (#ic# measures t#e &el stren&t#* %#e &el is measured (it# (it# a ruler in its container and a&ain a"ter bein& in)erted onto a plate* %o measure t#ic+enin& po(er a line spread test can be conducted usin& a line spread apparatus* mold is "illed (it# t#e sample and t#en is li"ted li"ted "rom t#e sample, allo(in& t#e mixture to disperse on a pattern o" concentric circles to measure its distance tra)eled )iscosit'-* i""erent starc# sources contain )ar'in& amounts o" am'lose and am'lopectin, t#ere"ore (ill produce di""erent results re&ardin& &elatini!ation and &el "ormation 1-* %#e concentration o" t#e starc# as (ell as t#e time and temperature used to #eat it and added in&redients ma' #a)e an e""ect on &elatini!ation & elatini!ation 1-, and t#e "ollo(in& experiments (ill obser)e (#at #appens durin& t#e &elatini!ation process (#en c#an&in& t#ese "actors* Materials and Methods
For t#e "irst procedure t#e starc#es used (ere (ax ' corn, corn starc#, rice starc#, potato starc#, (#eat starc#, all purpose "lour, and arro(root* 1 &rams o" eac# o" t#e starc#es (ere measured on a scale and eac# (as dissol)ed in 26 ml o" cold (ater measured in a &raduated c'linder- in a small pan* drop o" t#e starc# dissol)ed in (ater (as placed on a microscope slide and (as stained (it# Lu&ol rea&ent and a nd co)ered (it# a co)er co)e r slip* %#e slide (as obser)ed under t#e microscope and t#e s#apes and si!es o" t#e starc# &ranules (ere noted* t#ermometer (as t#en #eld in t#e pan, ma+in& sure to not touc# t#e sides or o r bottom, and t#e starc# mixture (as coo+ed on t#e sto)e o)er medium #eat until boilin& (#ile stirrin& (it# a (ooden spoon* %#e end temperature (as mar+ed and a line spread test (as conducted on t#e #ot paste* %#e #eated starc# (as )ie(ed under t#e microscope "ollo(in& t#e same procedures as t#e uncoo+ed starc#* %#e rest o" t#e mixture (as placed into a small custard cup and (as co)ered (it# saran (rap and placed in a s#allo( pan (it# ice (ater until it (as cooled to 24 de&rees 5* pon t#e completion
Mundt 3 o" coolin&, a percent sa& test (as to be done i" t#e product "ormed a &el, and anot#er line spread test (as to be done i" t#e product (as still a sol* /n t#e second procedure 64 &rams o" corn and potato starc# (ere eac# (eied and (ere eac# dispersed in 744 ml o" cold (ater in a small saucepan* t#ermometer t#ermometer (as #eld in t#e pan (#ile t#e mixtures (ere #eated, not touc#in& t#e sides or bottom* %(o tablespoons o" t#e mixture (ere remo)ed "rom t#e pan (#en it reac#ed 60, 80, 0, 70, and 7 de&rees 5, and a&ain (#en t#e mixture boiled or reac#ed its maximum possible temperature* line spread test (as done (it# t#e t(o remo)ed tablespoons at eac# temperature* &rap# (as plotted to determine t#e pea+ )iscosit' and t#e mixture (as #eld at t#e pea+ )iscosit' temperature "or 20 minutes (#ile bein& stirred continuousl'* %#e %#e mixture (as t#en cooled in a s#allo( pan "illed (it# ice (ater and t#e temperature (as constantl' bein& recorded* line spread test (as done a&ain e)er' 10, 20, 30, 40, and 0 de&rees less t#an t#e pea+ )iscosit' temperature (#ile t#e mixture (as coolin&* For procedure t#ree, 1 &rams & rams o" corn starc# (as dispersed (it# )arious in&redients in small saucepans* %#e "our combinations (ere as "ollo(s9 1 &rams o" corn starc# and 0 &rams o" su&ar in 26 ml o" (ater, 1 &rams o" corn starc# mixed in 200 ml o" (ater and 6 ml o" lemon :uice, 1 &rams o" corn starc# in 26 ml o" a *2; *2 ; alp#a am'lase solution, and 1 &rams o" corn starc# mixed (it# 26* &rams o" butter in 26 ml o" (ater* %#e dr' in&redients (ere measured usin& a scale (#ile t#e (et in&redients (ere measured in a &raduated c'linder, c 'linder, and t#e "our corn starc# combinations (ere put in separate saucep ans* Eac# o" t#ese combinations (ere )ie(ed under t#e microscope prior to bein& #eated, "ollo(in& t#e same protocol as procedure one* t#ermometer (as t#en suspended in t#e pan and t#e mixtures (ere stirred (it# a (ooden spoon (#ile bein& #eated on t#e sto)etop* %#e mixtures (ere coo+ed under medium.lo( #eat
Mundt 4 (#ile stirrin& until t#e temperature reac#ed 7 de&rees 5 or until t#e end temperature point (as reac#ed* %#e #ot mixture (as t#en )ie(ed under t#e microscope "ollo(in& t#e same procedures p rocedures as experiment one* line line spread test (as per"ormed usin& eac# o" t#e #ot mixtures and t#en t#e remainin& mixtures (ere placed in custard cups an d co)ered (it# saran (rap* %#e custard cups (ere placed in a s#allo( pan "illed (it# ice (ater and t#eir temperatures (ere recorded until reac#in& 24 de&rees 5* Line spread or percent sa& tests (ere per"ormed on eac# mixture (#en t#e' cooled to 24 de&rees 5, dependin& on i" t#e' (ere still a sol or i" t#e' turned into a &el* ll results (ere recorded t#rouout t#e experiment and s#ared (it# t#e class, as not e)er' &roup & roup conducted t#e experiments on t#e same products or combinations* pon t#e completion o" t#e t#ree experiments all materials used (ere cleaned and returned to t#eir proper locations* Results
%emperature %emperature and added in&redients #ad an e""ect on t#e &elatini!ation o" )arious starc#es* %#e multiple starc#es used eac# #ad di""erent end temperatures t#e' could reac#* Some starc#es (ere )er' )iscous (#en #eated, (#ile ot#ers (ere not as )iscous* pon coolin&, some starc#es "ormed a &el (#ile ot#er remained a sol* ddin& ddin& in&redients to t#e starc#es a""ected t#eir abilit' to &elatini!e, 'et did not a""ect t#eir end temperature* Table Table 1. Procedure 1: The Effect of Temperature Temperature on the Gelatinization Gelatinizatio n of Various Starches End !ine !ine # Transparenc$ Consistenc$ General Sample Temperature Spread Spread Sag %ppearance (in degrees ("ot (Cold C 88 3 . . . . . 36; %ranslucent %#ic+, N< &a'$ lobb' 2 . . . . . 8; Opaue el Li+e =#ite Corn ice 76 2 . . . . . 66; Not >er' Firm 5loud', %ransparent (#ite<&ra' Potato 84 2 . . . . . 2; %ransparent %#ic+ el 5lear and %#ic+ &heat 77 1 . . . . . 2; Not Firm 5loud', %ransparent =#ite
Mundt %P )lour
%rro*root
6<76
, 7 *
...
78
4, 1
8*, 12
...
Not %ransparent, 5loud' %ransparent
%#ic+ Sol
%#in Sol
5loud'
5lear
Table 1. The Effect of Temperature on the Gelatinization of Various Starches %#e )arious starc#es used all #ad di""erent boilin& points, ran&in& "rom 84 de&rees 5 to 77 de&rees 5* %#e (ax' corn, corn, rice, potato, and (#eat starc#es (ere "ree "lo(in& as a sol (#en #eated to t#eir respecti)e boilin& points, but "ormed "ormed a &el (#en cooled cooled to 24 de&rees 5* ll ll purpose "lour and and arro(root (ere "ree "lo(in& at t#eir boilin& points and (#en cooled* ? "lour and arro(root (ere less )iscous t#an t#e ot#er starc#es*
Procedure 1: +icroscop$ ,bser-ations Coo/ed -s. 0ncoo/ed Starches Waxy Corn 0ncoo/ed: Small, clear circles (it# a "e( 0ncoo/ed: ra' and tan )er' small s(irled scattered dar+ purple spots t#rouout circles Coo/ed: %in' purple dots (it# a (#ite and pin+ blotc#' bac+&round Rice 0ncoo/ed: ?urple, (#ite, and blac+ &rain' appearance
Coo/ed: Lar&e dar+ blotc#es o)er a "ibrous appearin& bac+&round Potato 0ncoo/ed: Lar&e dar+ &ra' o)als and circles
Coo/ed: ?in+ s(irled pattern (it# a "e( lar&e purple circles t#rouout Tapioca N/A
Wheat 0ncoo/ed: Small blac+ circles
Coo/ed: @lue and (#ite s(irled appearance, loo+s li+e a cloud AP Flour
Coo/ed: No ima&e a)ailable
0ncoo/ed: 5lear circles o)er a lit bac+&round
0ncoo/ed: Man' dar+ specs on a lit bac+&round
Coo/ed: ar+ "ibers (it# a dar+ bac+&round
Coo/ed: Less dar+ specs (it# a more "ibrous appearance
Arrowroot
=#en )ie(in& )arious coo+ed and uncoo+ed starc#es under t#e microscope, t#e' all #ad di""erent appearances* appearances* %#e microscopic c#an&es t#at occur to a starc# (#en #eated (ere obser)ed*
Table . Procedure : Temperature and Pea/ Viscosit$ of Corn and Potato Starch Type o !ine spreads or # sag tests Starch 23 degrees C 43 degrees C 53 degrees C 63 degrees C 67 degrees C Steps 1-4 5orn Starc# 23 21 3 ?otato Starc# 1 4 6 Pea/ 813 degrees 8 3 degrees 8 93 degrees 8 3 degrees Steps 6-9
Mundt 6
5orn Starc# ?otato Starc#
Viscosit$ 3 4
C 2 3
C 2 4
C 1 * 4
C 1*2 3
Table . Temperature and Pea/ Viscosit$ of Corn and Potato Starch Line spread test (ere done at increments o" 10 de&rees to determine t#e a""ect o" temperature on corn and potato starc# t#ic+enin&* t#ic+enin&* 5orn starc# starc# #ad a #ier line spread spread )alue t#an potato potato starc# at all increments increments (#en bein& #eated "rom "rom 60 de&rees 5 to 7 de&rees de&rees 5, t#ere"ore, (as less less )iscous t#an t#e potato potato starc#* =#en =#en bein& cooled "rom "rom t#e pea+ temperature temperature and measured measured at 10 de&ree increments, increments, t#e corn corn starc# became became slitl' t#ic+er and more )iscous, (#ile t#e potato starc# )iscosit' did not c#an&e muc#*
)igure 1. Procedure : The Pea/ Viscosit$ of Corn and Potato Starch
%#e #iest temperature corn starc# (as able to reac# (as 7 de&rees 5, (#ile t#e #iest temperature t#e potato starc# could could reac# (as 80 de&rees de&rees 5* =#en coolin& coolin& t#e starc# mixtures mixtures and conductin& conductin& line spread tests tests at e)er' 10 de&rees, t#e corn starc# mixture (as measured at 7, , 8, 6, and de&rees 5* Line spread tests (ere done on t#e potato starc# mixture at 80, 60, 0, 40, and 30 de&rees 5*
Table 9. Procedure 9: The Effect of %dded ;ngredients on the Gelatinization of Corn Starch Sample End !ine !ine # Transparenc$ Consistenc$ General Temperature Spread Spread Sag %ppearance (degrees C ("ot (Cold * 5orn 7 2 . . . . . 3 1; %ranslucent %#ic+ el 5lear A Su&ar @* 5orn 7 . . . . . 4 2; Opaue %#ic+, Lit A Smoot# Bello( Lemon 5* 5orn 7 2 0 ... Not So"t, %#ic+ 5loud' A alp#a %ransparent m'lase * 5orn 7 2 0 ... Not So"t, %#ic+ %#ic+ A @utter %ransparent %#e added in&redients did not #a)e an a""ect on t#e boilin& point o" t#e starc#* =#en lemon (as mixed (it# corn starc# it resulted in a less )iscous product (#en a line spread (as done at 7 de&rees 5 t#an (#en su&ar, alp#a am'lase, am'lase, and butter (ere mixed (it# t#e starc# and measured measured at 7 de&rees 5* %#e cooled starc# and su&ar mixture #ad a smaller percent sa&, so it "ormed a stron&er &el t#an t#e corn and lemon mixture (#ic# #ad
Mundt 8 a slitl' lar&er percent sa&* %#e corn and alp#a am'lase and corn and butter mixtures did not mo)e (#en doin& a line spread test (#en cooled to 24 de&rees 5, so t#e' also &elatini!ed into so"t, t#ic+ products*
!iscussion
urin& starc# &elatini!ation t#e #eated (ater molecules brea+ some o" t#e (ea+er #'dro&en bonds o" t#e starc#, so (ater penetrates t#e starc# &ranule and it be&ins to s(ell 2-* Some o" t#e am'lose mo)es out t#e starc# &ranule, and t#e mixture starts to beco me t#ic+ as t#e (ater "orms #'dro&en bonds (it# t#e am'lopectin 2-* %#e o r&ani!ation o" t#e &ranule structure is lost as t#e mixture continues to be #eated 2-* s (ater continues to be ta+en up b' t#e &ranule, am'lose (ill +eep bein& pus#ed out o" t#e &ranule (#ic# (ill "orm a "ilamentous net(or+, (#ere pastin& occurs and t#e mixture becomes t#ic+ 2-* %#e results o" t#is process (ere obser)ed (#en )ie(in& t#e coo+ed and uncoo+ed mixtures under t#e microscope* /" t#e mixture is #eld at a #i temperature "or too lon& t#e &ranules (ill collapse and t#e t#ic+ness (ill be lost 1-* More am'lopectin in a starc# (ill result in a so"t &el due to a lot o " intermolecular interaction, ma+in& it more di""icult to "orm &els, (#ile am'lose can "orm &els more easil' 2-* /n procedure one, it (as "ound t#at )arious starc#es #a)e di""erent boilin& points and )ar'in& t#ic+enin& po(er and abilit' a bilit' to &el, as can be seen in table 1* =ax' =ax' corn starc# contains )er' little am'lose, resultin& in t#ic+enin& po(er and a so"t &el, but a more unstable paste 2-* 5orn starc# #as an am'lose content o" o " 2;, so can easil' "orm a &el 2-* @ecause o" t#e #ier am'lose content in corn starc# t#an (ax' corn, t#e percent sa& s#ould #a)e been lo(er in t#e corn starc# t#an t#e (ax' corn, co rn, as it s#ould #a)e "ormed a stron&er &el* $ice starc# #ad a similar )iscosit' and &el stren&t# as corn starc#, su&&estin& t#at t#e t(o ma' #a)e similar am'lose contents, (it# rice #a)in& slitl' less* ?otato starc# contains lon& am'lose molecules (#ic# causes a tendenc' to t#ic+en earl', more more t#an an' ot#er starc# 2-* %#e results seen (ere
Mundt expected "or potato starc#, as it #ad stron& &el stren&t#* =#eat starc# #as a #i protein content, ma+in& it less e""ecti)e as a t#ic+ener 2-* Co(e)er, it does "orm a &el in sauces and continues to t#ic+en durin& coolin&, (#ic# (as obser)ed* %#e (#eat starc# (as t#e most )iscous at its boilin& point and also "ormed t#e stron&est &el, (#ic# (as due to its #i am'lose content* =#eat =#eat starc# and corn starc# #a)e t#e same am'lose content, so it (as expected "or t#em to #a)e similar t#ic+enin& po(er and &el stren&t#, t#ou t#is (as not seen* ll purpose "lour and arro( root #ad less t#ic+enin& po(er t#an all o" t#e ot#er starc#es obser)ed and did not "orm &els, indicatin& a lo( am'lose content* Cuman error can account "or t#e unexpected unex pected results in t#is procedure, suc# as incorrect measurements, not stirrin& enou or too or too )i&orous stirrin& causin& premature &ranule rupture, or bein& #eated past t#e &elatini!ation temperature prior to measurin& t#ic+enin& po(er and &el stren&t# 1-* /n procedure t(o t#e corn starc# (as less )iscous at all temperatures (#en bein& #eated t#an t#e potato starc#, due to t#e "act t#at potato starc# tends to t#ic+en earl' more t#an ot#er starc#es 2-* 5orn starc# #as a medium )iscosit' (#en co mpared to potato starc# (#ic# #as a )er' #i )iscosit', and t#is (as obser)ed* ?otato starc#, #o(e)er, #ad a lo(er pea+ temperature t#an t#e corn starc#* %#e potato starc# be&an to &elatini!e earlier t#an t#e corn starc# and "ormed less )iscous pastes (#en coolin& t#an t#e corn starc#* %#is can be explained because potato starc# is +no(n to #a)e #i )iscosit' pastes (it# &ranules t#at brea+ easil' and decrease in )iscosit' 2-* =#en coolin& t#e mixtures, t#e corn starc# continued to t#ic+en to "orm a &el (#ile retro&radation also increases t#e )iscosit' durin& coolin& 2-* /n procedure t#ree t#e e""ect o" additi)es on starc# &elatini!ation (ere obser)ed* =#en addin& su&ar to t#e starc#, t#e su&ar competes (it# t#e starc# "or (ater so less (ater is a)ailable "or &elatini!ation 1-* %#is dela's &elatini!ation and decreases t#e )iscosit' and &el stren&t# 1-*
Mundt 7 %#e results seen (ere not expected, as t#e &el "ormed (it# corn starc# and su&ar (as stron&er t#an t#e &el "ormed b' corn starc# in experiment one* %#is (as due to #uman error* cid decreases t#e t#ic+ness o" t#e cooled product, (#ic# is (#' addin& lemon :uice to corn starc# decreased t#e )iscosit' 1-* %#e acid brea+s t#e s(ollen starc# &ranules and causes #'drol'sis 2-* %#e line spread )alue "or t#e lemon corn c orn starc# mixture pro)es t#is* Fats result in a complex interaction (it# am'lose (#ic# titens t#e internal structure o" t#e product, reducin& &elatini!ation 2-* %#e corn starc# and alp#a a m'lase mixture as (ell as t#e corn and butter bu tter mixture did not #a)e percent sa& tests conducted on t#em, so t#e &el stren&t# (it# t#ose additi)es are un+no(n* Co(e)er, line spread tests (ere done on t#ese mixtures and s#o(ed )er' #i )iscosit', so so t#e abilit' to &elatini!e is present in t#ose mixtures* /t (ould be expected "or t#e corn and butter mixture to #a)e a dela' in &elatini!ation because o" t#e "at interaction* %#e corn and alp#a am'lase mixture s#ould also slo( do(n t#ic+enin& and &elatini!ation, because alp#a am'lase brea+s do(n starc# 1-* @ecau se o" t#e concepts discussed in class, t#e ou tcome o" t#ese experiments could be some(#at predicted and better explained, (#ile "actors t#at in"luence t#e &elatini!ation o" starc# #as been made clear*
Mundt 10
$e"erences 1-* @ro(n, m'* Understanding Food Principles and Preparation Preparation 4 4t# ed-* =ads(ort#, 5en&a&e Learnin&, 2011, pa&e 371.404* 2-* Simpers, $* 2014-* 5lass notes, $ut&ers ni)ersit', 7<12<2014*