Copyright is owned by the Author of the thesis. Permission is given for a copy to be downloaded by an individual for the purpose of research and private study only. The thesis may not be reproduced elsewhere without the permission of the Author.
THE RHEOLOGY OF BUTTER
A thesis presented
in partial fulfillment of the
requirements for the degree
of Doctor of Philosophy
in Food Technology
at
Massey Pniversity.
Michelle Harnett
1989.
i i
Abstract.
A para l l e l p l at e vi s co e l a s t omet e r was b ui lt t o per form creep
c o mp l i ance t e s t s on b utter and re l ated fat s . C reep movement
w a s mea s ured with a l inear di spl acement t rans d ucer and
r e c o rded by a data l ogger de s i gned and b ui l t f o r c reep
c o mp l i ance expe r iment at i on .
A t emperat ure o f 1 0 °C was ma intained by p l acing the para l l e l
p l at e vis c o e l as t omet e r in a re f rigerated incubat o r .
A s e r i e s o f pre l iminary expe r i ment s e s t ab l i shed the creep
r e sponse was l inear and that t he direct i o n in wh i ch some
s amp l e s we re sheared was cri t i cal . The d urat i on o f creep
c o mp l i ance t e st ing was a l s o fo und to a f fect r e s ul t s .
C reep behavi o ur o f b utter wa s a s s umed t o be v i s co e l a st i c
( based o n p revi o us st udies ) and was mode l led with a
genera l i z ed Ke lvin mode l . El a s t i c and v i s co us parameters were
f itted to the dat a by a Marquadt non- l i near l e a s t squares
c urve algor ithm . Cont inuo us ret ardat i o n spect r a we re found by
p l ott ing L(�) against ln t ime . Data whi ch had been both
s moothed and di f fe rent i ated by the met ho ds of S av i t z ky and
G o l a y (1964) showed evidence o f the e xi st ence o f three or fou�
m a in group s o f ret ardat i on mechan i sms .
O n remova l o f stre s s a fter creep comp l i ance t e s t ing a part i a l
r e c ove ry o f st rain w a s observed, howeve r , s amp l e s fai l ed t o
r ecove r a s m uch a s p redi cted b y v i s co e l a s t i c t h e o r y . A second
c reep / recovery cycle re s ulted in a respons e s s im i l ar in
magn i t ude to the f i r s t recove r y . All fat produ c t s tested
s h owed the s ame pat t e rn of response o n repeated creep / recove ry
c y c l ing .
An expl anat ion , bas e d on the behavi o r o f p o l yme r s , was put
f o rward t o exp l a i n t he obs e rved pat t e rn o f respon s e . The
i ii
c r y s t a l network was tho ught t o a l i gn in the direct i on in whi ch
s t r e s s was app l ied . The format i o n o f new ' bonds ' was t hen
tho ught to l ock the network in i t s ' new p o s i t i on .
A n umbe r o f s amp l e s were rewor ke d , The c reep c urve seen on
creep/ re cove ry cyc l ing o f reworked samp l e s was s im i l a r in
s hape to t h at s een for t he o ri g i n a l s amp l e s . Howeve r , the
c urve s were t hree to fo ur t imes great e r than tho s e s een for
t he original s amp l e s . I n gen e ra l , creep re sponse wa s f o und t o
b e inve r s e l y proport i onal t o hardne s s .
The ret ardat i on spect ra o f reworked samp l e s di f fered from
t h o s e seen for the o r i ginal s amp l e s in s everal way s . The
spect ra wer e smoothe r , the b ul k o f the spectra had moved t o
short e r t ime s and t he y were l a rger than those seen for the
o r i ginal s ampl e s .
A s urvey o f s e a s on a l b utter s amp l e s was a l s o unde rt aken . C reep
comp l i ance paramet e r s were fo und t o corre l ate we l l with
s e ct i l it y hardne s s and s o l id . fat c ontent .
•
i v
Aim of Study.
The a ims o f t h i s work a r e :
a ) T o s t udy t h e rhe o l og i ca l prope rt i e s o f but t e r a n d re lated
fat product s by a creep comp l i ance method .
b ) T o gain a c l earer unde r s t anding o f the re l at i onship between
rhe o l ogical propert ies , comp o s i t i on and s t r uct ure o f b utter
and r e l ated product s .
c ) T o us e thi s knowledge t o improve the rhe o l o g i c a l properties
of b ut t e r .
V
Acknowledgments.
I am indebt ed t o my s upervi s o r s D r . M . W . T ay l o r , Dr . J. LeLievre , D r . R . Lambert and D r . R . Norr i s , who s e advice and
s upport wa s grat e fu l l y rece ived . I am a l s o i ndebt ed to the New
Z e a l and D a i r y Re search I n s t i t ute who funded t he pro j ect in the
form o f a re se arch contract . In addi t i on I wou l d l i ke to thank
A l a s t a i r MacGibbon , Trevor B i s s e l l and othe r membe rs o f the
Mi l k fat S ect i on , New Z e a l and D a i r y Re se arch I nst itute for
t he i r ide a s and d i s cu s s i on . Inva luable techn i ca l a s s i st ance
was rende red by t he t echn i c a l s t a f f of the Food Techn o l ogy
D epartment , Mas s e y Unive r s i t y and by the Da i ry Products
D eve l opment Cent re s t a f f , New Z e a l and D a i ry Re s e a rch
I n s t i t ute . F i na l l y , thanks to TD for moving to Pa lme rs to n
North.
List of Contents.
ABS TRACT . i i
A IM . iv
ACKNOWLEDGE MENTS . v
C HAPTER ONE : AN INTRODUCT ION IN THREE PARTS .
P a rt A : Rhe o l ogy .
lA . l. Int roduct ion .
1 A . 2 . S t re s s and s t rain .
1A . 3 . S o l i ds , l i qu ids , p l a st i c s .
1A . 4 . V i s c oe l a st i c s .
1A . 5 . Me chan i ca l mode l l i ng .
1A . 6 . Fundament a l t e st ing .
1A . 6 . 1 . Stat i c t e st ing .
1A . 6 . 2 . Dynam i c test ing:
1A . 7 . Emp i r i c a l t e s t ing .
P a rt B : Me asu rement o f the rhe o l og i c a l paramet e r s o f but t e r
1
1
1
1
2
7
7
10
10
19
2 2
and margarine . 23
l B . l . Int roduct i on . 2 3
1B . 2 . Fundament a l t echn i que s . 2 3
1 B . 2 . 1 . Creep comp l i ance . 2 3
1 B . 2 . 2 . Cont i nuous she a r .
1 B . 2 . 3 . Dynam i c t e s t ing .
1 B . 3 . Emp i r i c a l and imitat ive t e s t ing .
1 B . 3 . 1 . Sect i l it y ha rdne s s .
1 B . 3 . 2 . E xt ru s i on .
1 B . 3 . 3 . Compre s s ion .
1 B . 3 . 4 . Pene t r omet ry .
1 B . 3 . 5 . Spreadab i l it y s i mu l at i on .
P art C : But t e r and margar ine .
lC . l . I n t roduct i on .
1 C . 2 . Butter
34
3 7
4 1
4 1
4 3
4 5
4 7
5 0
5 1
5 1
5 1
1 C . 2 . 1 . Manu f acture .
1 C . 2 . 2 . S t rut ure .
1 C . 2 . 3 . F act o rs af fect ing rhe ol ogy .
1 C . 3 . Margarine
1 C . 3 . 1 . Man u f acture .
1 C . 3 . 2 . S t ruture .
1 C . 3 . 3 . F act o rs af fect ing rheology .
1 C . 4 . Ammi x but t e r .
1 C . 4 . 1 . Man u f acture .
1 C . 4 . 2 . S t ruture .
1 C . 4 . 3 . F act o rs af fect ing rheo l ogy .
1 C . 5 . A ft e rward .
C HAP TER TWO : MATERIALS .
2 . 1 . But t e r f rom comme rc i al dai ry fact o ri e s .
2 . 1 . 1 . Comme rc i al s amp l e i dent i ficat i on .
5 1
5 4
5 5
6 2
6 2
6 6
6 7
7 2
7 3
7 3
7 5
7 8
7 9
7 9
7 9
2 . 2 . B ut t e r made u s ing di f fe rent c ream cool ing techn iques . 7 9
2 . 3 . Butt e r and anhydrous product s made f rom the s ame fat . 8 0
2 . 4 . Rewo rk ing . 8 3
2 . 5 . S t o rage . 8 4
C HAP TER T HREE : E S TABL I S HED MET HOD S .
3 . 1 . E xt ract i o n o f mi l k f at .
3 . 2 . S e ct i l it y h ardness .
3 . 3 . F at t y ac i d c ompo s it ion .
3 . 4 . T ri g l y c e ri de compo s it ion .
8 5
8 5
8 5
8 6
8 8
3 . 5 . S o l i d f at content by nuc l e ar magnet i c re s o n ance . 8 8
3 . 6 . S o l id f at cont ent by di f fe rent i al s c anning c al o rimet ry . 8 9
3 . 7 . Compari s on o f nuc l e ar magnet i c re s o n ance and di f f e rent i al
s c an n i ng c al o rimet ry .
C HAP TER FOUR : CREEP CO MP L I ANCE MET HOD .
4 . 1 . The i n s t rument .
4 . 2 . Temp e rat u re ' cont ro l .
4 . 3 . The dat a c o l l e ct i on s y stem .
4 . 4 . S amp l e p rep arat i on , l o ading and runn i ng .
4 . 5 . Rec ove ry and l o ad cyc l i ng .
4 . 6 . D at a an al y s i s .
9 0
9 2
9 2
9 4
9 6
10 0
10 3
1 0 3
4 . 6 . 1 . Creep curve s . 10 3
4 . 6 . 2 . Re coverey . 114
4 . 6 . 3 . P resent at i on o f re s u l t s . 1 1 4
4 . 6 . 4 . Retardat i o n spect r a . 117 4 . 7 . P re l iminary exper iment s . 12 9
4 . 7 . 1 . L inearit y . 12 9
4 . 7 . 2 . Orientat i o n . 12 3
4 . 7 . 3 . Repe at ab i l i t y . 141
C HAP T ER F IVE: LARG E D EFORMAT ION T EST ING. 149
5 . 1 . I nt roduct i on . 149
5 . 2 . Expe r iment a l method . 15 2
5 . 3 . Expe riment a l and result s . 15 3
5 . 4 . D i s cus s i on . 16 3
5 . 5 . Conclu s i on . 17 2
5 . 6 . Tradit i onal s e ct i l it y ha rdne s s t e s ti n g vs . l a rge
de f o rmat ion t e s t ing . 17 2
C HAP T ER S I X : AN INTROD UCT I ON TO CREEP CO MP L IANC E
EXP ER I MENTAT I ON .
P a rt A
6A . 1. Exper iment a l .
6A . 2 . Re su l t s .
6A . 3 . D i s cu s s ion .
P a rt B : But t e r s manu factured u s i n g di fferent cream coo l ing
t e chn i ques .
6B . l . Expe riment a l .
6B . 2 . Re sult s .
6B . 3 . D i s cu s s i on .
C HAP T ER S EVEN : T HEORY .
7 . 1. Int roduct ion .
7 . 2 . Load c y c l ing .
7 . 2 . 1 . Expe riment a l .
7 . 2 . 2 . Re s u l t s .
7 . 2 . 3 . D i s cu s s i on .
7 . 3 . Rework i n g .
17 4
1 7 ·4
17 4
17 4
17 6
17 8
17 8
17 8
17 9
18 1
18 1
18 1
18 1
18 1
19 1
19 4
7 . 3 . 1 . Experiment a l . 1 9 4
7 . 3 . 2 . Re sult s . 1 9 4
7 . 3 . 3 . D i s cu s s i on . 2 0 4
7 . 4 . Deve l opment o f a theory t o e xpl a in ob s e rved behavi our . 2 0 6
7 . 4 . 1 . I ntroductory comment s . 2 0 6
7 . 4 . 2 . Theory A . 2 0 6
7 . 4 . 3 . Theory B . 2 0 8
Chapt e r E i ght : But t e r and Anhydrous P roduct s made from the
S ame F at . 2 1 3
8 . 1 . I nt rodu ct i on . 2 1 3
8 . 2 . Expe r iment al . 2 1 3
8 . 3 . Re s u lt s . 2 1 4
8 . 3 . 1 . Sect i l it y hardne s s and sol id fat cont ent . 2 1 4
8 . 3 . 2 . Creep comp l i ance . 2 2 9
8 . 4 . D i s c u s s ion . 2 3 5
8 . 4 . 1 . Compo s i t i on 2 3 5
8 . 4 . 2 . Reworking . 2 4 2
C HAP TER N I NE : SEAS ONAL TREND S I N FRI T Z AND AMMI X BUTTER . 2 4 5
P art A : E s t ab l i shed methods . 2 45
9A . 1 . I nt roduct i on . 2 4 5
9A . 2 . Experiment a l . 2 4 5
9A . 3 . Re s u l t s and di s cu s s i on . 2 46
9A . 3 . 1 . Sect i l it y hardne s s . 2 4 6
9A . 3 . 2 . S o l i d fat content . 2 46
9A . 3 . 3 . Compar i s on between sect i l i t y hardne s s and s o l i d
fat cont ent . 2 5 1
9A . 3 . 4 . D i f fe rent i a l s canning ca l o r imet ry . 2 5 5
9A . 3 . 5 . Fatty a c i d compo s it i on . 2 5 6
9A . 3 . 6 . Triglyceride c ompo s i t i ion . 2 6 1
9A . 4 . Conclu s i on .
P art B : C reep compl i ance .
9 B . 1 . Exp e rimenta l .
9 B . 2 . Re s u lt s .
9 B . 3 . D i s cu s s ion .
9 B . 4 . Con c l u s i on .
2 6 4
2 6 5
2 6 5
2 6 5
2 7 1
2 7 2
CHAP TER TEN : GENERAL D I S CUS S ION .
1 0 . 1 . D eve l opement o f the c reep comp l i ance method .
1 0 . 1. 1. Equ ipment .
10 . 1. 2 . Data C o l l e ct i on .
10 . 1 . 3 . Tempe rature Contro l .
1 0 . 1 . 4 . Accuracy .
1 0 . 2 . D at a ana l y s i s .
10 . 2 . 1. The V i s c oe l a s t i c Mode l .
10 . 2 . 2 Dat a Ana l y s i s .
10 . 2 . 3 . Ret a rdat ion Spectra .
10 . 2 . 4 . Approp r i atene s s o f the Mode l .
1 0 . 3 . P re l iminary Exper iment s .
10 . 3 . 1. L i n e a r i t y .
1 0 . 3 . 2 . Durat ion o f E xper iment .
10 . 3 . 3 . Orient a t i on o f Sample .
10 . 4 . Load Cyc l i ng .
1 0 . 5 . P roduct s made from t he same fat .
1 0 . 6 Rewo rked pr oduct s .
10 . 7 . Seasonal s u rvey .
1 0 . 8 . Conc l u s i on and future work .
APP END I X 1: Computer P rograms .
2 7 4
2 7 4
2 7 4
2 7 4
2 7 5
2 7 5
2 7 6
2 7 6
2 7 7
2 7 8
2 7 8
2 7 9
2 7 9
2 8 0
2 8 2
2 8 4
2 8 9
2 9 0
2 9 1
2 9 3
2 9 6
APP END I X 2 : Non- l inear Lea s t Square s Cu rve F i t t ing Re s u lt s . 3 13
APPEND I X 3 : D i f fe rent i a l S cann ing C a l o r imetry Me l t i ng
The rmograms , 19 8 5 - 19 8 6 S e ason .
REFERENCE S .
3 42
3 5 6
List of Tables.
Table 1 . 1 : Creep r e s u l t s report ed by var ious worker s . 2 6
Table 1 . 2 : Re sults repor t ed b y D a v i s ( 1 9 73 ) us ing a var iety o f r heological met hods . 2 9
Table 1 .3 : Compar i s on o f the results repor ted by S hama and S herman ( 1 9 7 0 ) and Gupta a nd D eMan ( 1 9 8 5 ) . 3 1
Table 2 . 1 . Pr oduct ion conditions used i n the manufacture o f butt er and anhydr ou s pr oduct s from the s an e milk fa t . 8 2
Table 2 . 2: Product temper atur e s recorded dur ing pr oduct ion of butter and a nhydr o u s pr oduc t s from the same milk fa t . 8 2
Table 3 . 1 : Compo s i t i on o f standard a� hydr ous mi lk fa t . 8 7
Table 3 . 2: Norma l iz ing factor s f or fat t y acid we ight per centage s , relat ive to c 16 : o· 8 7
Table 4 . 1: The e f fect o f varyi�g the n umb er of exponent i a l terms used i n f it t ing dat a to the pr e f i ned mode l . (Sample TUI A ugu st ' 86 , 1 0°C . ) 1 1 0
Table 4 . 2 : P arameter s f itted t o cr eep c ompl iance dat a by two met hods , e xponen t i a l pee l ing and non-l inear c�rve f itt ing . 1 13
Table 4 . 3 : A compar i s on o f retardat ion t imes calculated by a lea s t sq uares c ur ve f i t t ing pr ogr am ( NONLIN ) and tak en from conti nuous r e t arda t ion s pectr a, F igures 4 . 2 0 and 4 . 2 2 . 1 2 8
Table 4 . 4: S tr a in r e sponses observed o n the applicat ion o f s tr e s s . 13 1
Table 4 . 5 : Cr eep compl iance par ameter s f ound for one s ample on t he app licat ion o f dif fer ent str e s s e s . 13 1
Table 4 . 6 : Cr eep compl iance parameter s obt a ined fr om patted Fr itz butt er s s he ar e d i n t he thr ee poss ible direction s . 13 4
Table 4 . 7 : Recover y dat a f or the butter TUI Apr i l ' 8 7 . 13 6
Table 4 . 8: Cr eep compliance par ameter s obt a ined from patted Fr itz butter s sheared i n two direct ions . 13 6
Table 4 . 9 : Cr eep compl iance par ametr s obta ined from unpatted Fr i tz but ter s sheared i n two dir ect ions . 13 8
Table 4 . 1 0 : Cr eep compliance par ameter s fitted t o cr eep curves observed for t he butter TT January , 1 9 8 6 . 1 4 4
Table 4 . 1 1: Creep c ompl iance par ameter s f itted t o cr eep curve s observed for t he butter TT Apr i l , 1 9 8 6 . 1 4 7
Table 5 . 1 : P er centage solid fat determined by NMR and tr adit ional sect i l ity h ardrie s s values a t 1 0°C for butt er s used in large de f orma t ion t e s t ing . 1 5 4
Table 5 . 2 : An e xample o f dat a reco rded by the Perkin E lme r dat a s ta t io n dur i ng la rge de fo rmation tes t ing . 16 1
Table 5 . 3 : Comparison o f sectility hardness tes t ing ( t radi t io n a l ) with s he a r t es t ing .
Table 5 . 4: Sect i lity hardness results ( C R Analys e r ) .
16 4
16 4
Table 5 . 5: The fit o f v a r io us models to shear speed vs . fo rce data fo und at 5 , 1 0 a nd 1 5° C fo r four s amples express ed as co rre lat io n coe f f i c ients . 16 9
Table 6 . 1 : Rheo logical pa rameters fo und fo r creep and reco v ery experiments o f d i f fe ring length . 1 7 5
Table 6 . 2 : Sect i lity hardness v a lues a t 1 0°C fo und fo r but t e rs manufactured f ro m c ream s ub j ected to di f fe rent c re am coo l ing techniques . 1 8 0
Tab l e 6 . 3 : C reep compl iance pa ramete rs f itted to t he c reep res ponse o f but t e rs manufactured from c ream s ub j ected to di f fe rent c ream coo l ing techniq ues . 1 8 0
Table 7 . 1 : Sect i l ity ha rdness es and so l id fat co ntents o f s e lected det e rmined at 1 0° C . 1 83
Table 7 . 2 : C reep compl iance parameters fo r s amp les co l lected t h roughout the yea r . 1 8 7
Table 7 . 3 : Ov erall creep respo ns e d isp layed by s amples co l lected thro ughout t he yea r . 1 8 8
Table 7 . 4 : Co r relat ion co e f f ic ients fo und between v a r io us c reep compliance pa rame t e rs and sect i lity ha rdness fo r s amples o f butte r co llected t h ro ughout t he yea r . 1 8 9
Table 7 . 5: Creep compliance pa rameters f itted to o riginal and rewo rked but t e r pa i rs . 1 9 5
Table 7 . 6: P e rcent age changes s een i n creep respo nse o n t he rewo rking o f but t e r s amp les . 1 9 7
Table 7 . 7 : Pecent age change fo und i n s elect ed pa ramet e rs o n compa ring f i rs t and seco nd c reep respo ns es . 1 9 7
Table 7 . 8: Ret a rdation t imes found fo r o rigianl and rewo rked butters . 2 0 3
Table 8 . 1: S e c t i lity hardness res u l ts , 1 0°C . 2 1 5
Table 8 . 2 : So l id fat contents as det e rmined by NMR . 2 1 5
Table 8 . 3 Creep compliance parame t e rs fo r o r igina l and rewo rked s amples o f but t e r , plas t i c ized milkfat and a mi lkfat/o i l blend manufactured f rom t he s ame fat so urce . 2 2 0
Table 8 . 4: Co r relat ion coe ff i c ients found between v a r io us c reep comp l iance pa r amet e rs and sect ility h a rdness' fo r o rigina l and rewo rked butters ,
plast ic ized milk f at and milk fat/ o i l blend m anufact u red f rom th e s ame f at . 2 2 1
Table 8 . 5 : Pe rcent age ch anges seen i n various param eters go ing f rom o r iginal t o rewo rk ed .
Table 8 . 6 : Comparison o f second c reep response with the f i r st c reep response .
23 1
233
Table 9 . 1 : The sect i l ity h a rdness o f s amples o f patted butte r det e rmined at 1 0° C . 2 4 7
Table 9 . 2: Pe rcentage solid fat a s det ermined by NMR for s amples o f milk fat ext racted f rom F r itz butt e r . 2 4 9
Table 9 . 3: P e rcent age solid fat a s det e rmined b y NMR for s amples o f milk fat ext racted f rom �� ix butt e r . 2 5 0
Table 9 . 4 : Fatt y acid composit ion o f F ritz b utt e r s col lect ed dur ing the 1 9 8 5 - 1 9 8 6 season . 2 57
Table 9 . 5 : Fatt y acid compos s iton o f Amm ix butt e r s collect ed du ring th e 1 9 8 5 - 1 9 8 6 season . 2 5 8
Tab le 9 . 6 : Trigly ce ride com po s it ion o f F r itz b utt e rs collected du ring th e 1 9 8 5 - 1 9 8 6 season . 2 6 2
Table 9 . 7 : Triglycer ide compo sit ion of Amm ix butt e rs colle cted during th e 1 9 8 5 - 1 9 8 6 season . 2 63
Table 9 . 8 : Creep com pl iance paramet e rs f itted t o butters . 2 67
Table 9 . 9: Co rrelat ion coe f f ic ient s found between sect i l it y h a rdne s s a nd s o l id f at content and c reep compl iance paramet e rs for a numbe r o f b utt e rs .
2 6 9 Table 9 . 1 0 : C reep compliance par amet e r s f o r samples collect ed th rough out the yea r . 2 7 0
List of Figures.
F igure 1 . 1: Rate o f sh ea r vs . sh ear for a Bingh am plast i c . 6
Figu re 1 . 2: Standa rd rh eological m ode ls : a) Hookean sprin g , b) Newton ian da shpot , c ) St Ven ant glide r . 8
F i gure 1 . 3: Rh eological m odel s: a) B ingh am plast i c , b ) Max wel l un it , c) Kelvin un it and d) , Burgers m ode l . 9
F i gu re 1 . 4: Typic a l c reep an d recove ry curve for a plast ic f at . 1 3
Figure 1 . 5 : A m ode l c reep cu rve . 1 4
F igure 1 . 6: The generalized Kelvin m odel . 16
Figu re 1 . 7: St re s s re spon s e t o s in uso ida l st rain . 2 1
Figure 1 . 8: Creep parameters repo rted by G upt a an d D eMan ( 1 9 8 5 ) plotted again st force used . 3 3
Figure 1 . 9: Th e m odif ied Bin gh am body . 36
Figu re 1 . 1 0: a) Th e Vis cous -Max we l l -Bingh am mode l (D e in e r and He ldman, 1 9 86) , b) st uctural applicat i on of the m ode l . 3 9
Figure 1 . 1 1: Th e P a s i lac HCT 2 cont in uous butterm aker . 5 3
Figure 1 . 1 2: D i f f e rent ial scann ing calorim et ry m e lt in g th e rm ogram o f a F r itz butter . 5 7
Figure 1 . 1 3: D iagram of a sect ion th rough a sc raped s u rface heat exchange r . 6 4
Figure 1 . 1 4: Cont in uous soft m a rga rine p roduct ion ( E r i ks on, 1 9 8 5) . 6 5
F igure 1 . 1 5: D i f f e rent i a l s cann in g calorim et ry m e lt in g th e rm ogram o f a t ab le m a rgarine . 6 9
Figure 1 . 16: Th e Amm ix proce s s . 7 4
F igure 1 . 1 7: D i f f e rent i a l scann ing calorim et ry m e lt in g the rm ogram of an Amm ix b utte r. 7 7
F igure 2 . 1: P lant con f igurat i on used in the m an u fa ct u re o f butt e r an d anhydrous product s f rom t he smae f at . 8 1
F igure 4 . 1: The pa rallel p l at e viscoelast ometer . 9 3
F igure 4 . 2 : Diffe rent ial s c ann ing calorim et ry m e lt ing therm ogram i l lust rat in g the c hanges in s o l id fat content with tem pe r ature at 1 0 and 1 5oC . 9 5
F i gu re 4 . 3 : Fluct u at i on in tem pe rat ure obse rved ove r � f o rt y hour period . 9 7
F igure 4 . 4: D at a collect ion syst em . 9 8
F igure 4 . 5: Ch a rt recorde r t race seen on pe rforming a c reep compl iance expe r iment . 9 9
F igure 4 .6: P lan and s ide views o f th e s ample cutt e r . 1 0 1
F igure 4 . 7: A c reep and recove ry curve . 1 0 4
F igure 4 . 8 : A c reep compl iance curve sh owing ext rapo l at ion back t o 0 t ime . 1 06
F igu re 4 . 9: Ln Q plotted aga inst t ime sh owing th e st r a ight l ine port ion of th e graph ext rapo lated to 0 . 1 0 8
F igure 4 . 1 0 : Creep and recove ry curve s sh owing inst a nt aneous comp l iance, th e s um o f comp l i ances recovered and th e un recovered st r a i n . 1 1 5
F igure 4 . 1 1: Re sult presentat ion b y th e curve f itt ing p rogram NONLIN . 1 16
F igure 4 . 12 : An ideal cont inuous ret a rdat ion spect rum c a lculated for the s ample MAN May 1 9 8 7 . 1 1 9
F igure 4 . 13 : Ret a rdat ion spect rum found f o r the sample MAN May 1 9 8 7 us ing raw dat a . 1 2 0
Figure 4 . 1 4 : Cont inuous reta rdat ion spect rum found f o r MAN May 1 9 8 7 a fter smooth ing raw dat a . 122
F igure 4 . 1 5 : Th e ideal cont inuous ret a rdat ion spect rum found for MAN May 1 9 8 7 a ft e r smooth ing . 122
F igure 4 . 16: Th e cont inuous ret a rdat ion spect rum found f o r MAN May 1 9 8 7 a ft e r different iat ing th e raw dat a . 123
F igure 4 . 1 7: Th e ideal cont inuous ret a rdat ion spect u rm f ound for MAN May 1 9 8 7 a ft e r diffe rent iat ing according t o the meth od o f S az itz ky and Go lay ( 1 96 4) . 123
F igure 4 . 1 8: Th e ideal cont inuous ret a rdat ion specturm f ound for MP� May 1 9 8 7 a ft e r a 13 point cubic different iat ion . 1 2 4
F igure 4 . 1 9 : Th e ideal cont inuous ret a rdat ion specturm f ound for MAN May 1 9 8 7 a ft e r a 7 point qua rt i c different iat ion . 1 2 4
F igure 4 . 2 0 : The cont inuous ret a rdat ion spect u rm found f o r MAN May 1 9 8 7 a ft e r smooth ing and different iat ing according t o the meth od o f S avitz ky and Golay ( 1 96 4) . 1 2 5
F igure 4 . 2 1 : Th e ide a l cont inuous ret a rdat ion specturm found for MAN May 1 9 8 7 a ft e r smooth ing and di f fe rent iat ing according to th e meth od o f Savitz ky a nd G o l a y ( 1 96 4 ) . 1 2 5
F igure 4 . 2 2 : The cont inuous ret a rdat ion spect u rm found f o r MAN Apr i l 1 9 8 7 a ft e r smooth ing and di f fe rent iat ing �ccording t o the meth od o f S avitz ky and Golay . 1 26
F igure 4 . 2 3: The ideal cont in uous ret a rdat ion s pecturm foun d for MAN April 1 9 8 7 a ft e r smoot h ing and di fferent i at in g according to t he method of S avitzk y an d Golay ( 1 9 6 4) . 1 2 6
F igure 4 . 2 4: Th ree dimen s ion a l axes imposed on a pat o f butt e r . 1 3 3
Figure 4 . 2 5: Ope rat ing prin c iples o f t he S ig FD 1 4 0 patt e r . 1 3 9
F igure 4 . 2 6 : Creep compliance curve s foun d f o r t he samp le T T Jan ua ry ' 8 6 . 1 4 3
Figure 4 . 2 7: Creep compl iance curves foun d for the samp le T T Ap ril ' 8 6 . 1 4 5
Figure 5 . 1 : Front an d s ide views o f t he apparat us att ached t o t he c R An a lyser used for shea r test ing . 1 5 1
Figure 5 . 2: Force vs . shear speed f o r t he sample TUI Februa ry 1 9 8 7 . 1 5 5
Figure 5 . 3 : Force vs . s hea r speed f o r t he samp le MAN MAy 1 9 8 7 . 1 56
Figure 5 . 4 : Force vs . shear speed f o r t he sample TT Februa ry 1 9 8 7 . 157
Figure 5 . 5 : Force vs . s hear speed f o r t he s ample TT M a rch 1 9 8 7 . 1 5 8
Figure 5 . 6: Shear fa i lu re st res s plotted aga in st tempe rat ure . 16 0
Figure 5 . 7 : St ress vs . distance moved by the p robe . 16 2
F igure 5 . 8 : Fo rce vs . s hear speed f o r both she a r te st in g an d sect i l it y h a rdness test ing, sample MAN May 1 9 8 7 . 165
Figure 5 . 9: Force vs . s hear speed f o r bot h shea r test ing an d sect i l it y ha rdn e s s test ing, sample T T Ma rch 1 9 8 7 . 166
F igure 7 . 1 : Typical c reep complian ce curve seen on repeat edly applyin g an d removin g st res s . 1 8 4
Figure 7 . 2: Cont in uous reta rdat ion spect ra foun d for the butt e r TUI April 1 9 8 7, a ) f i r st c reep respon se, b ) , s econ d c reep respon se . 1 8 5
Figure 7 . 3: Cont inuous ret ardat ion spect ra foun d for t he butte r T T March 1 9 8 7, a ) f i r st c reep respon se, b ) , secon d c reep respon se . 1 86
F igure 7 . 4: Fi rst and secon d c reep c u rves observed for the but e r TUI Ma rch 1 9 8 7 . 1 9 2
F igu re 7 . 5: Cont inuous reta rdat i on s pect ra foun d for t he butt e r TUI Ma rch 1 9 8 7, a ) f i r st c reep_ re spon se, b ) , secon d c reep respon s e . 1 9 9
F igure 7 . 6: Cont inuous reta rdat ion spect ra foun d for t he butte r T T Feb . 1 9 8 7, a ) f i r st c reep respon se, b ) , s e cond c reep respon se . 2 0 0
F igure 7 . 7: Cont inuous ret a rdat ion spect ra found for t he reworked butter TUI Ma rch 1 9 8 7, a) f i r st c reep respon se, b ) , second c reep respon se . 2 0 1
F igure 7 . 8 : Cont i nuous ret a rdat ion spect ra foun d f o r the rewo rked butt e r TT Feb . 1 9 8 7, a) first c reep response, b) , secon d c reep re sponse . 2 0 2
F igure 8 . la : Di fferent i a l scann ing calorimetry m e lt in g th e rm ogram found for o ri g in a l plast i c ized m i l kfat . 2 16
F i gu re 8 . l a : D i f fe rent i a l scann i ng calorimetry m e lt ing therm ogram found for rewo rked plast ic ized m i l kf at . 2 1 7
F igu re 8 . 2 a : D i f ferent ia l scann ing calorimetry m e lt ing the rmogram found for origin a l m i lkfat/ o i l blend . 2 1 8
Figure 8 . 2b : D i f ferent ia l scann ing calorim etry m elt ing th e rm ogram found for rewo rked m i lkfat/ o i l blend . 2 1 9
Figure 8 . 3 : Cont in uous ret a rdat i on spect ra found for plast ic ized m i lkfat : a) i n it ial creep respon se, b) secon d c reep re spon se . 2 2 3
Figu re 8 . 4 : Cont inuous ret a rdat ion spect ra found for butt e r : a) c reep respon se, b) second c reep respon se .
in it i a l 2 2 4
Figure 8 . 5: Cont in uous ret a rdat ion spect ra found fo r m i lk fat/ o i l bl en d : a) init i a l creep re spon se, b) second c reep re spon se . 2 25
F igure 8 . 6 : Cont in uous ret a rdat ion spect ra found f o r rewo rked plast ic ized m i l k f at: a) init ia l c reep re spon se, b) second creep respon se . 2 26
F igure 8 . 7 : Cont in uous ret a rdat i on spect ra found for reewo rked butt er: a) in it ia l creep respon s e, b) second c reep respon se . 2 2 7
Figure 8 . 8: Cont in uous ret a rdat ion s pect ra found f o r reworked m i lkf at/ o i l blend : a) init ia l c reep response, b) secon d creep respon se . 2 2 8
Figure 9 . 1 : The variat ion o f sect il it y h a rdness w ith season . 2 4 8
Figu re 9 . 2 : Th e variat ion o f pe rcent age s o l id fat with season . 2 5 2
Figure 9 . 3 : Solid f at cont ent plott ed aga i n st sect i l it y h a rdne s s showing l in e s of best f it for all s amples and F r itz and Amm ix butt e r s sepa rate ly .
2 5 3
Figure 9 . 4 : D i f fe rent ial s cann ing calorim et ry melt ing th e rm og ram s found for Oct ober an d December Amm ix butt ers 2 5 5
F igure 9 . 5 : We ight pe recent age s o f c 16: 0 and c 1 8 : l f o r Fritz and Amm ix butt ers col lected ove r th e ' 8 5 - ' 86 season . 2 5 9
F igure 1 0 . 1 : A c reep a nd recove ry curve . 2 8 1
F igure 1 0 . 2 : Typical c reep com p liance cu rve seen on repeatedly applying and rem o ving st re s s . 2 8 5
Figure 1 0 . 3 : P roposed rheological m odel s t o represent th e c reep compliance beh aviour of butt e r . 2 8 8
