Assessmen o in e acial iscoelas ic p ope ies o Faba bean (Vicia aba) 1
p o ein-adso bed O/W laye s as a unc ion o pH 2
Manuel Felix1, Albe o Rome o2, Cecilio Ca e a3, An onio Gue e o1,*
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1Depa amen o de Ingenie ía Química, Escuela Poli écnica supe io , Uni e sidad de Se illa, 41011 Se illa, 4
Spain. 5
2Depa amen o de Ingenie ía Química, Facul ad de Física, Uni e sidad de Se illa, 41012 Se illa, Spain. 6
3Depa amen o de Ingenie ía Química, Facul ad de Química, Uni e sidad de Se illa, 41012 Se illa, Spain. 7
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*An onio GUERRERO 15
Depa amen o de Ingenie ía Química, Escuela Poli écnica Supe io , Uni e sidad de Se illa, 16
41011 Se illa, Spain. 17
E-mail: ague e [email protected] 18
Phone: +34 954557179; ax: +34 954556447.
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Abs ac 20
In e acial heology may be ega ded as a powe ul ool domina ing he dynamics o complex 21
luid- luid in e aces. Mo e speci ically, heological p ope ies om shea measu emen s ha e 22
been pos ula ed as he mos use ul echnique o he assessmen o he mic os uc u e o 23
complex luid- luid in e aces, and i s ela ionship o long- e m emulsion s abili y. The aim o 24
his wo k was o e alua e he in e acial p ope ies o Faba bean (FB) p o ein as a unc ion o 25
p o ein concen a ion and pH alue (3.0, 5.0 and 8.0). The compa ison be ween esul s ob ained 26
om dila a ional and in e acial shea measu emen s p o ides accu a e de ails ela ed o he 27
mic os uc u e o he p o ein a he O/W in e ace. Viscoelas ic moduli o he p o ein adso bed 28
a he O/W in e ace we e ob ained h ough dila a ional measu emen s (T acke , IT Concep ), 29
as well as in e acial SAOS measu emen s, using a double wall- ing geome y i ed o a DHR3 30
heome e (TA In umen s). Resul s om dila a ional heology indica e ha p o eins a e able o 31
o m a ilm a O/W in e ace, whose s eng h depends on he pH alue (whe e E’ anges om 32
2.0·10-2 Pa·m a pH 5.0 o 5.5·10-3 Pa·m a pH 8.0). Howe e , hese measu emen s ha e shown 33
o be less sensi i e o pH modi ica ions han in e acial shea iscoelas ic measu emen s. 34
Rega dless o he pH alue, in e acial shea measu emen s can ollow he e olu ion o he 35
iscoelas ic beha iou o he O/W in e acial laye o e he de elopmen o he p o ein gel 36
ne wo k, as p o ein adso p ion p oceeds. This e olu ion indica es ha p o ein adso p ion akes 37
place much as e a pH 3.0 and 5.0 han a pH 8.0. 38
39
Keywo ds: Faba bean p o ein; In e acial Shea Rheology; Linea iscoelas ici y; Pendan 40
D ople ; P o ein adso p ion 41
1. In oduc ion 42
In e acial heology p o ides key in o ma ion o unde s anding he dynamic beha iou o 43
complex luid- luid in e aces, which a e he basis o no only d ople o ma ion and s abili y 44
in emulsions, bu also s uc u al and mechanical p ope ies (Wijmans & Dickinson, 1998). The 45
adso p ion o model globula p o ein molecules such as β-lac oblobulin, o albumin o BSA a 46
O/W has been p e iously s udied (E Dickinson, 1999). In ac , he e a e success ul s udies in 47
which he unde s anding o complex in e aces is p o ided by hei in e p e a ion as a quasi-48
wo-dimensional ne wo k o igid sphe ical pa icles, which ep esen globula p o eins and a e 49
c oss-linked (Wijmans & Dickinson, 1998). These models a e based on he p emise ha he 50
heological p ope ies obse ed o a globula p o ein adso bed a he O/W in e ace a e simila 51
o he ones ound o bulk gels (E ic Dickinson, 1998). Howe e , in a mix u e be ween di e en 52
kinds o p o eins (i.e., di e ing in molecula weigh , composi ion, con o ma ion, e c.), 53
adso p ion is e y complex. In hese cases, he compe i i e adso p ion be ween di e en kinds 54
o p o eins mus be aken in o accoun ( an Aken, 2003). Fo compe i i e adso p ion, models 55
only wo k o p o eins o eagen g ade (mainly BSA and β-Lac oglobulin) and molecules such 56
as su ac an s (Faine man, Lucassen-Reynde s, & Mille , 2003; Mille e al., 2000). Howe e , 57
comme cial ood p oduc s con ain a la ge numbe o di e en p o eins as well as o he 58
componen s such as s a ch, lipids and sal s, which makes i impossible o de e mine he eal 59
na u e o he di e en in e ac ions a he O/W in e ace. Consequen ly, he in e p e a ion o he 60
beha iou o hese complex luid- luid in e aces in e ms o undamen al in e ac ions is a e y 61
di icul challenge. Recen ly, in e acial heology has been used o o e come his p oblem, 62
s udying p o eins ypically in ol ed in cell exchanges o ood p oduc s (Bö che , Kepple , & 63
D usch, 2017; Rome o, Ve wijlen, Gue e o, & Ve man , 2013; Sch oyen, Gunes, & Ve man , 64
2017; Vandeb il, F anck, Fulle , Moldenae s, & Ve man , 2010). 65
Dila a ional heology and shea heology ha e been used o he in e p e a ion o p o ein 66
in e ac ions a luid- luid in e aces (Dano e al., 2015). The o me ela es changes in 67
in e acial ension when a d ople su e s oscilla o y dila a ions, whe eas he la e uses an 68
analogous in e p e a ion o h ee-dimensional bulk sys ems in in e acial sys ems (Maldonado-69
Valde ama & Pa ino, 2010). Howe e , bo h echniques, dila a ional and shea heology, need 70
o be ca ied ou o imp o e he in e p e a ion o he p o ein in e ac ions a he O/W in e ace. 71
Dila a ional heology has been co ela ed o sho - e m s abili y, whe eas in e acial shea 72
measu emen s ha e been ela ed o middle o long- e m s abili y o emulsions (Lucassen-73
Reynde s, Benjamins, & Faine man, 2010; Rome o e al., 2013). The e is a a ie y o de ices 74
o measu ing in e acial shea heology. Among hem, disc, bicone o double wall ing (DWR) 75
geome ies can be a ached o a highly sensi i e s ess-con olled heome e o cha ac e ise 76
complex luid- luid in e aces (Felix, Rome o, Sanchez, & Gue e o, 2019; Hoogh en e al., 77
2017; Na simhan, 2016), whe e DWR is pa icula ly use ul, since i minimizes he e ec o he 78
subphases on iscoelas ic esponse (which can be es ima ed h ough he Boussinesq numbe ) 79
(Felix, Rome o, Ve man , & Gue e o, 2016; Vandeb il e al., 2010). 80
As an al e na i e o adi ional p o ein concen a es ob ained by we pa hs, d y- ac ioning aims 81
o be mo e eco- iendly and cheape han he ypical acidic/alkaline solubilisa ion and 82
isoelec ic p ecipi a ion ollowed by sp ay-d ying; his new echnique allows a oiding bo h he 83
loss o p o ein unc ionali y, which usually akes place, and he was e p oduced in he ypical 84
isoelec ic p ecipi a ion (Clou , Walke , & Pike, 1986; Schu yse , Pelg om, an de Goo , & 85
Boom, 2015). The p o ein concen a e used in his esea ch was ob ained h ough a 86
d y- ac ioning p ocess, which is based on he di e ence o size be ween s a ch and p o ein 87
g anules. As an added bene i , his p ocedu e equi es a lowe amoun o ene gy inpu (Felix, 88
Lopez-Oso io, Rome o, & Gue e o, 2018). Mo eo e , he ood indus y is in e es ed in he use 89
o plan p o eins as an al e na i e o milk o egg p o eins o he de elopmen o O/W emulsions. 90
Plan p o eins, such as Faba bean (FB), possess a numbe o bene i s o being used in ood 91
applica ions. Thus, hey a e cos e icien , exhibi a high nu i ional alue (Ma ila e al., 2018) 92
and hey may also help o a oid some well-known alle gic p oblems associa ed o animal 93
p o eins. In addi ion, Faba bean belongs o he legume amily, which is he i h mos g own 94
c op in he wo ld, (Du, Jiang, Yu, & Jane, 2014). 95
The o e all objec i e o his wo k was o assess he in e acial p ope ies o Faba bean p o ein 96
concen a e as a unc ion o pH alue (3.0, 5.0 and 8.0) in a complex luid- luid in e aces, 97
which would con ibu e o he de elopmen o FB-s abilized emulsions. The in e acial 98
beha iou was analysed by means o dila a ional measu emen s (using a pendan d op 99
ensiome e ), and in e acial shea heology (using a DWR geome y a ached o a sensi i e 100
o a ional s ess-con olled heome e ). The compa ison o esul s ob ained by bo h echniques 101
may con ibu e o es ablish he po en ial use o FB p o ein sys em ob ained by d y ac iona ion 102
in ood p oduc s such as emulsions. 103
2. Ma e ial and me hods 104
2.1. Ma e ials 105
The Faba bean(FB) p o ein concen a e (He baP o F65) used wi hin he amewo k o his 106
esea ch was p o ided by He ba Ing edien s (San José de la Rinconada, Se ille, Spain). This 107
p o ein concen a e was ob ained om di ec ly milling d ied beans om FB, and, subsequen ly, 108
he powde ob ained was submi ed o a densi ica ion p ocess. This p ocess consis s on he 109
applica ion o a cen i ugal coun e - low. A e ha , pa icles whe e he d ag o ce is highe 110
han he cen i ugal o ce a e e used and a ligh e luen , which co esponds o he p o ein- ich 111
ac ion, is gene a ed (Felix e al., 2018). The sun lowe oil was pu chased om a local p oduce 112
(Co eysa, Se ille, Spain) and o he chemical eagen s we e pu chased om Sigma-Ald ich (S . 113
Louis, Missou i, USA). 114
2.2. P o ein cha ac e isa ion 115

The p o ein con en was de e mined in quad uplica e as % N x 6.25 (Vioque, Alaiz, & Gi ón-116
Calle, 2012) using a LECO CHNS-932 ni ogen mic o analyse (Leco Co po a ion, S . Joseph, 117
MI, USA). The lipid, mois u e and ash con en s o he FB p o ein concen a e we e de e mined 118
in quad uplica e by A.O.A.C. (2000) app o ed me hods. 119
2.3. In e acial cha ac e iza ion 120
2.3.1. De e mina ion o in e acial p essu e a equilib ium 121
Measu emen s o de e mine he sa u a ion concen a ion o O/W in e ace we e pe o med 122
using a Wilhelmy pla e connec ed o a Sigma D701 ensiome e (KSV, Helsinki, Finland). The 123
measu emen s we e ca ied ou a di e en p o ein concen a e amoun s (0.1, 0.25, 0.5, 0.75, 124
1.0, 2.0, 3.0, 4.0 and 5.0 w .%) and a h ee pH alues (3.0, 5.0 and 8.0). Thus, p o ein 125
dispe sions we e p epa ed in 40 mL essels, he pH was adjus ed by adding 2M HCl o NaOH 126
and he empe a u e was kep a 20 ºC o e nigh o allow he comple e adso p ion o he p o ein 127
a he in e ace. Then, he Wilhelmy pla e was placed a he wa e /ai in e ace and he essel 128
was illed up wi h sun lowe oil (gene a ing he O/W in e ace). The in e acial p essu e was 129
measu ed a e ob aining cons an in e acial ension alues. 130
2.3.2. Pendan d ople measu emen s 131
Pendan d ople measu emen s we e ca ied ou in o de o de e mine p o ein adso p ion 132
kine ics. T ansien in e acial p essu e and in e acial dila a ional measu emen s we e ca ied 133
ou using he TRACKER pendan -d ople ensiome e (IT Concep , F ance). An axisymme ic 134
d op was o med a he ip o he needle o a sy inge whose e icali y was con olled by a 135
compu e . The d ople p o ile was digi ized and analysed h ough a CCD came a coupled o a 136
ideo image p o ile digi ize boa d connec ed o a compu e . D op p o iles we e p ocessed 137
acco ding o he Laplace equa ion as was desc ibed by Cas ellani, Al-Assa e al. (2010). 138
In addi ion, he iscoelas ic moduli o p o ein adso p ion ilms we e de e mined a 10% s ain 139
ampli ude unde non-equilib ium a 0.1 Hz, as well as a di e en equencies ( anging om 140
0.0075 o 0.1 Hz) once he pseudo-s eady s a e was achie ed a e 10,800 s. All he expe imen s 141
we e ca ied ou , a leas in iplica e. The oil was con ained in an op ical glass cu e e (8 mL), 142
whe eas he p o ein solu ion was con ained in a sy inge (200 μL). Bo h elemen s we e 143
he mos a ed a 20.0 ± 0.1 °C (Sánchez & Pa ino, 2005). 144
2.3.3. In e acial shea heological p ope ies 145
The p o ein solu ion was placed in a double wall cup and hen a double-wall- ing (DWR) was 146
ca e ully laid a he ai /wa e in e ace. Subsequen ly, sun lowe oil was ca e ully added o 147
a oid any dis u bance o he in e ace. The ing was connec ed o a highly sensi i e magne ic 148
ai -bea ing s ess-con olled heome e (DHR-3, TA Ins umen s, USA) (Vandeb il e al., 149
2010). P io o equency sweep es s, s ess swep es s we e pe o med o de e mine he linea 150
iscoelas ic egion (LVR). Then, mechanical spec a we e ob ained by means o equency 151
es s, which we e ca ied ou wi hin he linea iscoelas ic ange. The equency sweep es s 152
we e pe o med du ing he p o ein adso p ion ( equency ange om 0.314 o 6.14 ad/s) and 153
a e eaching he pseudo-equilib ium s a e ( equency ange om 0.06 o 20 ad/s). In addi ion, 154
ime sweep expe imen s we e ca ied ou o e 10,800 s a 0.1 Hz o ob ain he in e acial 155
mechanical spec a o p o ein adso p ion o elucida ing p o ein-p o ein in e ac ions. All 156
expe imen s we e ca ied ou , a leas in duplica e and he sys ems we e he mos a ed a 20.0 ± 157
0.1 °C by coupling he double wall cup di ec ly on o he Pel ie bo om pla e. Mo eo e , o 158
neglec he con ibu ion o he subphase in in e acial small ampli ude oscilla o y shea 159
measu emen s (i-SAOS), he Boussinesq numbe (Bo) was calcula ed o all he sys ems 160
s udied. This numbe can be exp essed in e ms o a p opo ion be ween he iscosi ies o he 161
in e ace and he bulk (𝜂𝜂𝑠𝑠 and 𝜂𝜂𝑏𝑏, espec i ely): 162
𝐵𝐵𝐵𝐵 = 𝜂𝜂𝑠𝑠
𝑎𝑎·𝜂𝜂𝑏𝑏 (1) 163
whe e 𝑎𝑎 is a cha ac e is ic leng h (0.07 mm o DWR geome y). 164
Bo was abo e 100 in all cases (Bo > 100). These alues indica e ha he esponse ob ained is 165
solely ela ed o he in e acial con ibu ion (E ni e al., 2003; Vandeb il e al., 2010). 166
2.4. S a is ical analysis 167
A leas h ee eplica es o each measu emen we e ca ied ou . Measu emen unce ain y was 168
de e mined by means o s anda d de ia ion. Mo eo e , signi ican di e ences (p<0.05) we e 169
analysed by means o ANOVA es s (Excel s a is ical package). 170
3. Resul s and discussion 171
3.1. P o ein sys em cha ac e isa ion 172
The chemical composi ion o FB p o ein concen a e has been epo ed in a p e ious s udy 173
(Felix e al., 2018). The p o ein con en ob ained a e he d y- ac ioning p ocess eaches up o 174
56.4 ± 0.1 w .%. Mo eo e , he densi ica ion p ocess le o a concen a e o low a (4.6 ± 0.3 175
w .%), mois u e (4.3 ± 0.8 w .%) and ash (4.7 ± 0.1 w .%) con en s. The ca bohyd a e con en 176
(es ima ed by di e ence) was up o 30 w .%. 177
3.2 Cha ac e isa ion o he O/W in e ace 178
3.2.1. De e mina ion o in e acial p essu e a equilib ium 179
Ini ially, alues o in e acial p essu e measu ed a e equilib ium (24 h p o ein adso p ion) a e 180
de e mined by means o a Wilhelmy pla e connec ed o a ensiome e . In e acial p essu e (Π) 181
alues a e calcula ed om he in e acial ension alues (σ) as ollows: 182
𝛱𝛱=𝜎𝜎0− 𝜎𝜎 (2) 183
Whe e 𝜎𝜎0 is he O/W in e acial ension alue measu ed in he absence o su ace ac i e agen s 184
(52 mN/m) and σ he expe imen al in e acial ension alue. 185
Resul s om in e acial p essu e as a unc ion o pH (3.0, 5.0 and 8.0) and FB p o ein 186
concen a e concen a ion ( om 0.1 o 5 w .%) a e plo ed in Fig. 1. As can be obse ed, he 187
inc ease o p o ein concen a ion in ol ed an inc ease in in e acial p essu e, un il i eached a 188
cons an alue. This is he ypical beha iou ound in o he p o ein/su ac an sys ems such as 189
milk p o eins (Niño & Pa ino, 1998) o soy p o eins (O iz, Sánchez, Niño, Añon, & Pa ino, 190
2003). The in e acial p essu e inc eases when he p o ein concen a ion concen a ion is below 191
he sa u a ion concen a ion o he O/W in e ace. Howe e , once he in e ace is sa u a ed, an 192
inc ease o p o ein concen a ion in he bulk does no in ol e a highe numbe o p o ein 193
molecules a he O/W in e ace. Consequen ly, he in e acial p essu e does no ise anymo e 194
(Sánchez & Pa ino, 2005). The e o e, acco ding o he esul s ob ained, he sa u a ion 195
concen a ion o he sys ems a pH 5.0 and 8.0 is eached a 2 w .%, whe eas a pH 3.0 i is 196
eached a 1 w.%, app oxima ely. These da a a e impo an , since all u he in e acial 197
expe imen s we e ca ied ou a hese FB p o ein concen a e concen a ions, a which he 198
in e ace is sa u a ed. On he o he hand, acco ding o Felix e al. (2018), he pH alue 3.0 is 199
below he isoelec ic poin (IEP) o he p o ein (3.5). The lowe concen a ion ound o pH 3.0 200
o in e acial sa u a ion may be ela ed o p o ein un olding, which akes place a his ex eme 201
pH alue. Thus, a pH 3.0, he un olded p o ein can co e he in e ace comple ely when he 202
bulk concen a ion is lowe (O. E. Pé ez, Sánchez, Piloso , & Rod íguez Pa ino, 2008). 203
Fu he mo e, he highes alue o in e acial p essu e a e eaching he pseudo equilib ium was 204
ound o he sys em a pH 8.0, whe eas equilib ium alues o he sys ems a pH 5.0 and 3.0 205
we e e y simila . These esul s may be ela ed o he closeness o he minimum solubili y o 206
he FB p o ein concen a e, which in ol es a lowe amoun o soluble p o eins a ailable o be 207
adso bed a he in e ace and, he e o e, would lead o lowe alues o su ace p essu e. Chang 208
e al. (2015) ound simila pH-in luence o o he legume p o eins. Mo eo e , hey hypo hesised 209
ha in e acial ension is ela ed o an op imum balance be ween he cha ge and hyd ophobici y 210
o he p o ein. Thus, acco ding o p e ious esul s he e iciency o FB p o eins o s abilise he 211
in e ace a pH 8.0 may be ela ed o he inc ease in su ace cha ges, as epo ed p e iously 212
(Felix e al., 2018). Thus, he ze a po en ial alues ound o FB concen a e we e ca. 15, -20 213
and -35 mV a pH 3.0, 5.0 and 8.0, espec i ely. In addi ion, a educ ion o i s hyd ophobici y 214
whe e he i s equency sweep a e 10 min o p o ein adso p ion indica es ha he in e acial 363
shea esponse is domina ed by he iscous componen a low equency. The e olu ion o he 364
iscoelas ic moduli o e he adso p ion ime shows a c osso e poin , which shi s along p o ein 365
adso p ion om low o high equencies. Ini ially, hese esul s may no be conside ed 366
consis en wi h he ones ob ained om dila a ional heology (whe e he c osso e poin was no 367
obse ed). Resul s om in e acial shea heology seem o indica e he abili y o he adso bed 368
p o eins o exhibi cohesi e in e ac ions wi h neighbou ing molecules (Na simhan, 2016). In 369
any case, a e eaching he pseudo-equilib ium alue (i.e. a e 180 min) all in e acial O/W 370
p o ein-based ilms showed a gel-like esponse, ega dless o he pH alue. These esul s om 371
in e acial shea heology no only demons a e ha i is possible o moni o he adso p ion 372
kine ics o he O/W in e ace; hey also allow ollowing he de elopmen o he p o ein gel 373
ne wo k a he in e acial laye by measu ing he mechanical spec a du ing ime ( heo-kine ics 374
o he p ocess). 375
Compa ison be ween dila a ional heology and in e acial shea heology 376
Table 1 compa es he an (δ) alues om dila a ional and shea measu emen s ( an(δ)s,0.1
dand 377
an(δ)s,0.1
s, espec i ely), as well as he dila a ional and shea in e acial elas ic moduli 378
(E′(δ)s,0.1
d and G′(δ)s,0.1
d, espec i ely) ob ained a 0.1 Hz a e he adso p ion o FB p o ein a 379
he O/W in e ace. Fi s o all, he low an (δ)s,0.1 alues ob ained (ei he ( an(δ)s,0.1
d o 380
an(δ)s,0.1
𝑠𝑠) con i m he p edominan gel-like beha iou o he in e ace. Howe e , his ma ked 381
solid cha ac e is di e en , and depends on he me hod used. Thus, an(δ)s,0.1
d alues a e equal 382
o lowe han 0.10 a any pH alue. Howe e , an(δ)s,0.1
𝑠𝑠 alues oscilla e be ween 0.2 and 0.3. 383
I is wo h men ioning ha o he low alues o he dila a ional iscoelas ic pa ame e s we e 384
p e iously ob ained o a a ie y o p o ein-s abilized in e acial laye s (Rome o e al., 2012; 385
Rome o, Beaumal, Da id-B iand, Co dobes, An on, e al., 2011; Rome o, Beaumal, Da id-386
B iand, Co dobes, Gue e o, e al., 2011). In addi ion, he compa ison o G′(δ)s,0.1
d alues 387

indica es ha no only s ong in e ac ions a he O/W in e ace ake place, bu also he o ma ion 388
o a densely packed in e ace (E ni, Windhab, & Fische , 2011; F ee e al., 2004). In any case, 389
his pa ame e co obo a es he s ong dependence on pH exe ed by he FB p o ein sys em, 390
whe e he ne con ibu ion o p o ein-p o ein in e ac ions o he in e acial ilm is simila a pH 391
3.0 and 5.0 (p o ein su ace posi i ely o null ne cha ged), whe eas a pH 8.0 he p o ein 392
in e ac ions a e weake (p o ein su ace nega i ely cha ged). This e ec may be ela ed o he 393
dependence o su ace cha ges and hyd ophobici y on pH alues, wi h he in e acial ac i i y 394
o FB p o eins being educed a alkaline pH. 395
4. Concluding ema ks 396
The use o he d y- ac ioning p ocess ca ied ou a oids he was e o la ge amoun s o wa e 397
as well as he exposi ion o p o ein o ex eme pH alues and hei undesi able side e ec s, 398
p o iding a FB p o ein concen a e (56.4 w .%) wi h high in e acial ac i i y. The esul s om 399
in e acial p essu e (П) a e eaching he equilib ium a he O/W in e ace indica e ha he 400
e ec o pH on su ace cha ges and su ace hyd ophobici y (H0) has a ema kable in luence on 401
in e acial p ope ies. The highe su ace p essu e was ound in he sys em a pH 8.0, whe e he 402
su ace is high nega i ely cha ged. 403
The esul s om he dila a ional iscoelas ic measu emen s indica e ha p o eins a e able o 404
o m a ilm wi h a gel-like beha iou a he O/W in e ace, whose s eng h depends, once again, 405
on he pH alue. Howe e , hese measu emen s ha e shown o be less sensi i e o pH 406
modi ica ions han in e acial shea iscoelas ic measu emen s. Mo eo e , he e olu ion o 407
iscoelas ic p ope ies can be mo e clea ly ollowed by his la e echnique, which shows ha 408
p o ein adso p ion akes place much as e a pH 3.0 and 5.0 han a pH 8.0. Rega dless o he 409
pH alue, i-SAOS measu emen s can ollow he e olu ion o he iscoelas ic beha iou o he 410
O/W in e acial laye o e he de elopmen o he p o ein gel ne wo k. Thus, in e acial 411
heokine ics can be use ul o de e mine he sol-gel ansi ion a he in e acial laye . 412
In summa y, hese esul s con i m he ele ance o pe o ming bo h in e acial ension and 413
in e acial shea measu emen s a he O/W in e ace. The o me measu emen s a e ele an o 414
he emulsi ica ion p ocess, whe eas he la e allow ollowing he de elopmen o he p o ein 415
mic os uc u e a he in e ace (i.e. in e acial heo-kine ics) which is ega ded o be use ul o 416
emulsion s abili y. Addi ionally, hey con ibu e o con i m ha Faba bean p o ein concen a e 417
ob ained by d y ac iona ion can p o ide s ong O/W in e aces, whe e he s onges in e ace 418
was ob ained a pH 3.0. 419
5. Acknowledgmen s 420
The au ho s acknowledge o Andalusian Go e nmen o hi ing his esea ch unde he esea ch 421
p ojec TEP-6134. Au ho s also acknowledge o He ba Ing edien s o supplying he p o ein 422
powde used in his esea ch. E en ually, he au ho s also acknowledge Uni e si y o Se ille 423
o he VPPI-US g an (Re .-II.5) o Manuel Felix. 424
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Figu e 4 634
635
636

Figu e 5 637
638
639
Figu e 6 640
641
0.1 110
F equency ( ad/s)
G'
s
G''
s
G'
s
G''
s
10min 60min
20min 90min
40min 180min
C
0.1 110
F equency ( ad/s)
G'
s
G''
s
G'
s
G''
s
10min 60min
20min 90min
40min 180min
B
0,1 110
10
-3
10
-2
F equency ( ad/s)
G'
s
, G''
s
/ (Pa·m)
G'
s
G''
s
G'
s
G''
s
10min 60min
20min 90min
40min 180min
A