Control of the whey protein-stabilized emulsion texture in a large range of concentration

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Control of the whey protein-stabilized emulsion texture in a large range of concentration

Marie Chevallier, Thibault Loiseleux, Christelle Lopez, Catherine Garnier, Alain Riaublanc, Thomas Croguennec

To cite this version:

Marie Chevallier, Thibault Loiseleux, Christelle Lopez, Catherine Garnier, Alain Riaublanc, et al..

Control of the whey protein-stabilized emulsion texture in a large range of concentration. Journées

Plénières du GDR SLAMM (Solliciter LA Matière Molle), Nov 2019, Roscoff, France. 2019. �hal-

02737415�

1

UMR STLO (Science et technologie du lait et de l’œuf), Agrocampus Ouest-INRA, 35000 Rennes, France

2

UR BIA (Biopolymères, interactions, assemblages), INRA, 44000 Nantes, France

* thomas.croguennec@agrocampus-ouest.fr GDR SLAMM, Roscoff, 19-21 Novembre 2019

STLO

Marie CHEVALLIER ¹ , Thibault LOISELEUX ² , Christelle LOPEZ ¹ , Catherine GARNIER ² , Alain RIAUBLANC ² , Thomas CROGUENNEC* ¹

Control of the whey protein-stabilized emulsion texture in a large range of concentration

C o n te x t

• New trends in Europe driven by consumer’s expectations

• More natural and healthier food products

• 100% milk products (without non-dairy additives)

• Innovative products (new uses and consumption habits)

• Additives are currently used to control dairy product quality (texture, heat stability, phase separation,…)

Research Questions How to control the texture of whey protein emulsions in a large range of protein concentrations without non-dairy additives?

• Whey proteins are - natural emulsifiers (adsorb to oil/water interface)

- heat-sensitive proteins (heat treatments are required to extent food product shelf life)

→ heat sensitive emulsions

→ texturized (gelled) emulsions

Fluid emulsions: Protein amount too low to build a

continuous network

Heat stability of whey protein emulsions (pH 7)

Heat-stable/

fluid

Heat-Gelation

Gelled emulsions : Network of proteins entrapping oil

droplets

At low whey protein concentration (<4%), gelled emulsions are obtained by using

non-dairy

gelling agents

At high whey protein concentration (≥4%), fluid emulsions are obtained by using non-

dairy

stabilizing agents Denatured

whey proteins

Heat-induced whey protein network Oil droplets Oil droplets

• Whey proteins : Large amount available around the world

Dairy manufacturers:

•add value to dairy compounds (e.g. aggregated whey proteins)

♦10% of the milk volume

♦>80% of the milk proteins (caseins)

♦90% of the milk volume

♦<20% of the milk proteins (

Whey proteins

)

From waste stream to value-added,

« gutter-to-gold » Smithers, 2008

- Exceptional biological value (amino acid composition)

- Ligand carriers (vitamins, minerals, fatty acids)

- Bioactive proteins and peptides

Excellent for human nutrition MILK

CHEESE WHEY

R e s u lt s

Observation at:

Oil droplet scale

Interface scale Emulsion aspect after 30

min of heating at 120°C Emulsion aspect after 1

min of heating at 120°C

Critical casein concentration

Emulsion heat stability according to casein content Emulsion texture in function of the whey protein aggregate (strands) and the casein concentrations

Observation at:

Emulsion scale

Interface scale

Emulsion texture changes with the oil droplet surface composition

Oil droplet

Caseins Oil droplet

Casein

Whey protein aggregates (strands)

Whey protein aggregates (microgels) shared between adjacent oil droplets Flocculated oil

droplets

How to design whey protein emulsions at high protein concentrations that are fluid after heating in the absence of non-dairy additives?

How to obtain texturized (gelled) emulsions at low whey protein concentrations without non-dairy additives ?

S tr a te g y

Stability of the continuous phase (replace native whey proteins

by heat-stable aggregated whey proteins: microgels)

1

Stability of the oil droplets (replace native whey proteins

by caseins)

2

Competition for the oil droplet

surface 3

Adsorbed proteins

(native whey proteins→caseins) Protein in the continuous phase

(Native whey proteins→microgels) Whey protein microgels

Native whey proteins

Homogenizationpressure

0.01 0.10 1.00 10.00 100.00

0 10 20 30 40 50

Inter-dropletdistance (µm)

Oil content (%) Connect oil droplets

with whey proteins aggregates(low density) :

strands

1

Control inter-droplet distance (oil content/

homogenization pressure) + use of caseinsas emulsifying agent

2

Whey protein aggregates used as oil droplet connectors (Low density/elongated whey proteins→strands)

Size of the whey protein aggregates

≈ inter-droplet distance

Caseins for stabilizing oil droplet interface

Oil inter-droplet distance in function of oil content and the homogeneization pressure

C o n c lu s io n

Heat stable emulsions are obtained at high whey protein concentration in the absence of stabilizing agent:

- By adding sufficient amount of caseins to cover oil droplets surface (control of the size and stability of the oil droplets

→

casein content (g) > mass of oil (g) × specific surface (m

²

/g of oil) × protein interfacial load (g/m

²

) (protein interfacial load ∼ 2mg/m

²

for caseins)

- By selecting large and dense whey protein aggregates (small number, low interfacial adsorption rate and low reactivity on heating)

Caseins Oil droplet

Oil droplet

Caseins

Whey protein aggregates (microgels) in the continuous phase of the emulsion

Texturized emulsions are obtained at low whey protein concentration in the absence of gelling agent:

- By selecting low density/elongated whey protein aggregates

- By using whey protein strands as « connector » at the surface of the oil droplets (size of the aggregates

∼

distance between oil droplets)

- In combination with the homogenization pressure, use caseins as emulsifiers to control the size of the oil droplets (distance between oil droplets)

→

casein content (g) < mass of oil (g) × specific surface (m

²

/g of oil) × protein interfacial load (g/m

²

) (protein interfacial load ∼ 2mg/m

²

for caseins)

Whey protein strands (= connecting agent)

Caseins (with homogenizing pressure, they control the oil droplet size and the

distance between oil droplets)

The number of « connectors » defines the texture of the emulsions (gel, viscous, fluid)

Connected oil droplets