Whey protein – a realistic approach –
designed products for the food
industry
P Havea & P Watkinson
Fonterra Research Centre, Palmerston
North, New Zealand
Introduction
˜
Use of whey protein
so far dominated by
functional applications.
˜
Technology driven – made whey products
(WPC) – find a way to use them.
˜
Industry demand – ability to tailor-make
products.
˜
Research – accumulate knowledge
è
Based on model systems, both pure and low
protein
è
Hard to translate to commercial reality and of
limited commercial value
˜
Use of whey protein
so far dominated by
functional applications.
˜
Technology driven – made whey products
(WPC) – find a way to use them.
˜
Industry demand – ability to tailor-make
products.
˜
Research – accumulate knowledge
è
Based on model systems, both pure and low
protein
è
Hard to translate to commercial reality and of
Functions drive uses of whey
protein
˜
Fundamental knowledge
×
=
Ø
commercial
reality
˜
Realistic approach – key requirements
è
Controlled process
è
Low cost
è
Consistent delivery of the desired functions
˜
Functional performance – dictated by protein
interactions in food systems.
˜
Current presentation – review protein
interactions and the functional performance of
whey proteins in food systems.
˜
Fundamental knowledge
×
=
Ø
commercial
reality
˜
Realistic approach – key requirements
è
Controlled process
è
Low cost
è
Consistent delivery of the desired functions
˜
Functional performance – dictated by protein
interactions in food systems.
˜
Current presentation – review protein
interactions and the functional performance of
whey proteins in food systems.
˜˜
What happen here that produce the function?
What happen here that produce the function?
˜˜
Can we control these for our advantage?
Can we control these for our advantage?
Native Changes &interactions Functional
performance
Better understanding of protein
interactions
Native proteins Appropriate conditions Non-covalent interactions -S-S-Covalent bonding
Two categories of protein
interactions
˜
Two broad categories of interactions
è Covalent – (-SS-) – strong, few per molecule, form slowly in a heated protein system.
è Non-covalent (hydrophobic, ionic etc.) – weak, many reactive sites per molecule, form quickly.
˜
Experiments with heating under different conditions
è Control (water) both covalent and non-covalent interactions.
è SDS (1%) – covalent (disulphide bonds only).
è DTT (10 mM) – no disulphide bonding, non-covalent only.
è NEM (1:1 molar ratio) – no new disulphide bonds – only those pre-existing in the system, interactions are non-covalent only.
˜
Two broad categories of interactions
è Covalent – (-SS-) – strong, few per molecule, form slowly in a heated protein system.
è Non-covalent (hydrophobic, ionic etc.) – weak, many reactive sites per molecule, form quickly.
˜
Experiments with heating under different conditions
è Control (water) both covalent and non-covalentinteractions.
è SDS (1%) – covalent (disulphide bonds only).
è DTT (10 mM) – no disulphide bonding, non-covalent only.
è NEM (1:1 molar ratio) – no new disulphide bonds – only those pre-existing in the system, interactions are non-covalent only.
Manipulation of protein
interactions
SDS DTT NEM control disulfide non-covalentProtein interactions and gel
properties
Control SDS NEM DTT Time (min) 60 80 100 120 140 160 180 G ' (P a ) 0 5000 10000 15000 20000 25000 30000 35000 80 ºC 80 – 20 ºC 20 ºC 20 - 80 ºC SDS Control NEM DTT 12% protein, pH 6.9, 80ºC, 30 minTexture mapping
30 40 50 60 70 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 Fracture StrainEffect of protein interactions on
texture
F ra c tu re S tr e s s ( k P a ) 12% protein, pH 6.9, 80ºC, 30 min Water SDS NEM DTT Mushy Rubbery Brittle ToughModifying target – -S
S-interactions
˜
Manufacturing considerations
è Purity of protein – removal of lactose, salts (e.g. Ca2+) and other non-functional components (e.g. GMP).
è Influence of other factors in food systems to which whey protein is applied: other ingredients, processing conditions, pH, presence of salt.
è Room for tweaking – for more suitable selections.
˜
Modified whey protein products
è How are they processed (cold-gelling WPC)?
è How are required functional properties (thickening, water holding, emulsifying properties) preserved?
˜
Manufacturing considerations
è Purity of protein – removal of lactose, salts (e.g. Ca2+) and other non-functional components (e.g. GMP).
è Influence of other factors in food systems to which whey protein is applied: other ingredients, processing conditions, pH, presence of salt.
è Room for tweaking – for more suitable selections.
˜
Modified whey protein products
è How are they processed (cold-gelling WPC)?
è How are required functional properties (thickening, water holding, emulsifying properties) preserved?
Tweaking
Modified WPC80 (-S
S- )
˜
Heating at low ionic strength
è
Can achieve a variety of functional properties.
è
Retain heat-gelling function and ability to form
gels at low temperatures.
è
May apply to products such as desserts.
è
Protein functions – dominated by
disulphide-linked interactions.
˜
Heating at low ionic strength
è
Can achieve a variety of functional properties.
è
Retain heat-gelling function and ability to form
gels at low temperatures.
è
May apply to products such as desserts.
è
Protein functions – dominated by
Protein interactions and gel
properties
Tim e (m in ) 6 0 8 0 1 0 0 1 2 0 1 4 0 1 6 0 1 8 0 G ' (P a ) 0 5 0 00 1 0 00 0 1 5 00 0 2 0 00 0 2 5 00 0 3 0 00 0 3 5 00 0 80ºC 80–20ºC 20ºC 20−80ºC SDS Control NEM DTT 12% protein, pH 6.9, 80ºC, 30 minHeating of CG WPC80
20−80ºC 80ºC 80−20ºC 20ºC 12% protein, pH 6.9 0.1 1 10 100 1000 10000 0 50 100 150 200 Time (min) S to ra g e M o d u lu s (P a ) ♦ Reconstituted in waterHeating of CG WPC80
20−80ºC 80ºC 80−20ºC 20ºC 12% protein, pH 6.9 0.1 1 10 100 1000 10000 0 20 40 60 80 100 120 140 160 180 200 Time (min) S to ra g e M o d u lu s (P a ) ♦ Reconstituted in water ■ Reconstituted in NEMHeating of CG WPC80
12% protein, pH 6.9 20−80°C 80ºC 80−20ºC 20ºC 0.1 1 10 100 1000 10000 0 20 40 60 80 100 120 140 160 180 200 Time (min) S to ra g e M o d u lu s (P a ) ♦ Reconstituted in water ■ Reconstituted in NEM ● Reconstituted in SDS20 - 80 ºC 80 ºC 80 - 20 ºC 20 ºC ♦ Reconstituted in water ■ Reconstituted in NEM ● Reconstituted in SDS ▲Reconstituted in DTT 20−80ºC 80ºC 80−20ºC 20ºC 12% protein, pH 6.9
Heating of CG WPC80
0.1 1 10 100 1000 10000 0 20 40 60 80 100 120 140 160 180 200 Time (min) S to ra g e M o d u lu s (P a )Texture
CG WPC80
Brittle Tough Rubbery Mushy water DTT SDS NEM ▼- WPC80 12% protein, pH 6.9, 80ºC, 30 minTexture
CG WPC80
Brittle Tough Rubbery Mushy water DTT SDS NEM ▼- WPC80 ● - CGWPC80 12% protein, pH 6.9, 80ºC, 30 minBrittle Tough Rubbery Mushy water DTT SDS NEM ▼- WPC80 ● - CGWPC80 12% protein, pH 6.9, 80ºC, 30 min
Texture
CG WPC80
Brittle Tough Rubbery Mushy water DTT SDS NEM ▼- WPC80 ● - CGWPC80 12% protein, pH 6.9, 80ºC, 30 min
Texture
CG WPC80
Brittle Tough Rubbery Mushy water DTT SDS NEM ▼- WPC80 ● - CGWPC80 12% protein, pH 6.9, 80ºC, 30 min
Texture
CG WPC80
Target – optimised non-covalent
interactions
˜
Manufacturing considerations
è Retention of salts (e.g. Ca2+) that have a major influence on functional properties.
è Influence of other factors in food systems to which whey protein is applied: other ingredients, processing
conditions, pH, presence of salt. ˜
Modified whey protein products
è Manipulation of processing conditions so that, upon
application, interactions of protein are dominated by non-covalent associations (MWPC).
è Main functional properties (soft-textured gels and limited emulsifying properties).
è Protein fortification applications.
˜
Manufacturing considerations
è Retention of salts (e.g. Ca2+) that have a major influence on functional properties.
è Influence of other factors in food systems to which whey protein is applied: other ingredients, processing
conditions, pH, presence of salt.
˜
Modified whey protein products
è Manipulation of processing conditions so that, upon
application, interactions of protein are dominated by non-covalent associations (MWPC).
è Main functional properties (soft-textured gels and limited emulsifying properties).
Effect of added [Ca] on texture
Tough Rubbery Mushy Brittle Added [Ca] g/kg = 0 = 1 = 2 = 3 = 4 = 5 = 8Effect of added [Ca] on viscosity
Heating time (min)
0 5 10 15 20 25 A p p a re n t v is c o s it y ( P a .s ) 0.0 0.1 0.2 0.3 0.4 0.5 5 g/kg added Ca
Control 1 (no added Ca)
20ºC 80ºC
12% protein, pH 6.9 Shear rate 250 s−1
Mushy Brittle Rubbery Tough -s-s- only -s-s- + nc nc only -s-s- + nc Texture mapping 30 40 50 60 70 0.7 0.8 0.9 1 1.1 1.2 1.3 1.4 Fracture Strain F ra c tu re S tr e s s ( k P a ) 12% protein, pH 6.9, 80ºC, 30 min Water SDS NEM DTT Mushy Rubbery Brittle Tough
Effect of protein interactions on
texture
Added [Ca] g/kg = 0 = 1 = 2 = 3 = 4 = 5 = 8 Tough Rubbery Mushy Brittle
Discussion and conclusions
˜
Whey protein – complex system, not easy to
translate fundamental knowledge to industrial
reality.
˜
Data presented – demonstrate effect of protein
interactions on the functional properties of
whey protein gels.
˜
A better understanding of protein interactions
and how they relate to functional properties in
food systems is required.
˜
May be able to manipulate the processing
conditions to make products with target
properties suitable for specific applications.
˜
Whey protein – complex system, not easy to
translate fundamental knowledge to industrial
reality.
˜
Data presented – demonstrate effect of protein
interactions on the functional properties of
whey protein gels.
˜
A better understanding of protein interactions
and how they relate to functional properties in
food systems is required.
˜
May be able to manipulate the processing
conditions to make products with target
Acknowledgement
˜
Scott Mackay – for doing the work
˜
Fonterra Research Centre (Steve Taylor)
˜
IWC-2008 – for the opportunity to participate
˜
Scott Mackay – for doing the work
˜
