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Emulsion structure

in relation to

sensory and and

digestive

functionality George van Aken george.vanaken@nizo.com

Jennifer Aniston (W Magazine photo shoot)

OPTIMAL FAT FORMULATION IN WEIGHT

MANAGEMENT PRODUCTS?

HOW CAN WE DESIGN EMULSIONS TO AVOID

OVEREATING?

FOCUS

COMBAT METABOLIC SYNDROME

Positive energy balance

Heilbron et al, Int. J. Obesity, (2004)

Ectopic fat storageliver, heart, pancreas.

skeletal muscle,abdominen

METABOLIC SYNDROME:

Obesity, CardioVascular Disease

inflammation, diabetes type II,

high blood pressure, atherosclerosis

Enlarged adipocytes:• Impared adiposite

differentiation and function

• Modulated endocrine

function

Fat storage exceeds

the normal storage

capacity of adipositesHigh blood triglycerides

Impaired glucose homeostasis

Approaches against metabolic

syndrome

• Reduce ectopic fat • Reduce caloric intake

• Increase satiety

• Sport

• Burn more fat, built more muscles

• Improved clearance of inflammatory pro-atherogenic blood lipoprotein remnants

• Increase in Omega-3 and short and medium chain fatty acid, Increase fibers. Reduce sugar. Increase fibers.

• Reduce saturated (palmitic) fatty acids (Challenged)

• Lower blood pressure, less vessel injury leading to better cardiovascular health

• Low salt, less stress

• Low glycemic index• Low sugar, slow starch, slower gastric emptying, slower absorption

Approaches against metabolic

syndrome

• Reduce ectopic fat • Reduce caloric intake

• Increase satiety

• Sport

• Burn more fat, built more muscles

• Improved clearance of inflammatory pro-atherogenic blood lipoprotein remnants

• Increase in Omega-3 and short and medium chain fatty acid, Increase fibers. Reduce sugar. Increase fibers.

• Reduce saturated (palmitic) fatty acids (Challenged)

• Lower blood pressure, less vessel injury leading to better cardiovascular health

• Low salt, less stress

• Low glycemic index• Low sugar, slow starch, slower gastric emptying, slower absorption

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Product requirements

• Should reduce caloric intake• Early satiety

• Long lasting hunger reduction

• Should be healthy• Low glycemic index

• Reduce blood triglycerides, improve inflammatory

response

• Should be preferred by consumer• Sensory quality

• Creamy, full taste and aroma

6

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Goals:

• Healthy: low calorie intake at satiety

• Sensorially liked: creamy, smooth, full

2 finalized projects at TIFN:

- Improved satiety by emulsified fat

- Improved creaminess by emulsified fat

7

Application

Contract research

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Main findings of the two

projects

• Sensory perception of emulsions determined

by the behaviour during oral processing

• Satiety by emulsions influenced by the

structure and dynamics in the gastro-intestinal tract

Needed is a better understanding and control of

the interactions of the emulsions with the

human body product formulation

8

ORAL BEHAVIOUR OF

EMULSIONS

Sensory pereption

9

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TIFN Project team:

Diane Dresselhuis

Erika Silletti

Guido Sala

Els de Hoog

Monique Vingerhoeds

Jan Benjamins

Franklin Zoet

Jerry van Maanen

Eefjan Timmerman

Willem Norde

Martien Cohen Stuart

George van Aken

Unilever

DSM

Cosun

Avebe

FrieslandCampina

NIZO food research

TNO

WUR

Product developers approach

Product development:composition, structure • reduced fat

• thickeners

• particles

• aroma’s

• sugar replacers

Product characteristics:sensory properties

• not so creamy, thin, slimy, gritty

• off tastes, off flavours, unbalanced flavours

Sensory paneling

correlations

Instrumental measurements:• viscosity, gel strength, fracture behavior

• friction measurement

• droplet and particle size

• aroma and flavour release

Correlations

are often

poor

10Together to the next level

After taste oral and

pharyngeal coating,

flavour release

Masticatoryoral processing

many structural changes,

flavour release

Sensory perception of food

First bite rheology, temperature

Gut signalsSatiety, well being

Brain

Receptors

Appearancecolor, shine,

structure, flow, aroma

swallow

Feed back

11Together to the next level

Tribological regimes of papillae

(Stribeck curve)

Static friction

speed

viscosity

Friction force

hydrodynamic

boundary

mixed

Only viscous

forces

Static surface bonds

Transient surface bonds and

corrugations

Liquid starts to

interpenetrate

palate

papilla Gap-width

increases with

speed viscosity

Hydrodynamic modelling

of the soft deformable

papilla surface*

* Van Aken, G.A., Modelling texture perception by soft epithelial surfaces, Soft Matter, 2010, 6, 826–834

“Rough

tongue”

astringency

“Smooth” thickness

particle size

Emulsions:

Large structural changes, even for thin liquid emulsions:

THIS is what you taste!

13Together to the next level

TI food and

Nutrition

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Saliva-induced

droplet aggregationFormation of slimy

structures

Fat spreading at air

bubble surfaces

Droplet coalescence

Release of

emulsions droplets

Droplet-coating of

oral surfaces

Amylase induced

starch breakdown

Structural changes in the oral cavityFood emulsions

Inhomogeneous coverage

of tongue papillae

Van Aken et al., Food Colloids, Dickinson ed., RSC, 2005, pp.356 – 366;

Curr. Opin. Colloid Interface Sci. 2007, 12, 251-262. .

Fracture of gels into

‘crumbs’

Droplet spreading at

tongue surface

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TI food and

Nutrition

Saliva-induced flocculation1:1 mixtures of emulsions with saliva

Emulsion -potential (mV)

0

10

20

30

40

50

-100 -50 0 50 100

d 32

emulsion

mixture

E. Silletti et al., Food Hydrocolloids 21 (2007) 596–606; J.Colloid Interface Sci. 313 (2007) 485–493

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Viscosity increases due to saliva-induced droplet

aggregation → increased creaminess

Saliva-induced

droplet

aggregation

Liquid emulsion

ξ < 0 ξ > 0

Vingerhoeds et al. Food Hydrocolloids, 23(3) (2009), 773-785.

Van Aken et al., Curr. Opin. Colloid Interface Sci. 12 (2007), 251-262. 16

at 100 s-1

TI food and

Nutrition

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Interaction with the tonguePhD study of Diane Dresselhuis

Visualization of fat

retention on pig tongue

CSLM image

500 500 m

10 wt% SF oil; 1 wt% WPI

red: oil; green: tongue papillae

Dresselhuis et al., Journal of Colloid and Interface Science (2008)

17

TI food and

Nutrition

Fat retention on the tongue

Fat adhesion and retention larger for more unstable emulsions

→ increased creaminess

emulsions varying in stability to coalescence

o/w emulsion

7% SF (sunflower oil)

stabilized with protein WPI

stable unstable

WPI 1 0.3

[%]

D[3,2] 0.92 1.15

[ m]

1.6 1.4

(@51 s-1)

[mPa s]

gra

m f

at

rem

ain

ing in m

outh

0 .0

0 .1

0 .2

0 .3

1% W P I S F 0.3 wt% W P I S F 1% W P I S F L

gra

m f

at

rem

ain

ing

in

mo

uth

spit

rinse

0.0

0.1

0.2

0 .0

0 .1

0 .2

0 .3

1% W P I S F 0.3 wt% W P I S F 1% W P I S F L

gra

m f

at

rem

ain

ing

in

mo

uth

spit

rinse

Fat

remaining

after first

spit

Fat

remaining

after water

rinsing

unstablestable

Dresselhuis et al., Journal of Colloid and Interface Science (2008)

18Together to the next level

TI food and

Nutrition

Friction between PDMS (hydrophobic) and glass (boundary friction regime)

Fat reduces the friction (→ increases creaminess), but an increase

in fat content has no further effect

0.0

0.2

0.4

0 10 20 30 40Fat content (wt%)

Friction c

oeffic

ient

unstable emulsionstable emulsion

0.6

Fat content (wt%)

0.3 wt%WPI

1.0 wt%WPI

Effect of adsorption of fat

onto the surface

Dresselhuis et al. Food Biophysics (2007)

Dewetting of saliva

from the oral surfaces

19Together to the next level

TI food and

Nutrition

LUBRICATING

FATTY COATING

rubbing,

shear

EXTENDED

aroma release

Liquid

emulsion

shear

saliva

HIGHER VISCOSITY by saliva

–induced droplet flocculation

Droplet coating

on oral surfaces

saliva

VISCOUS

BOLUS of

gel particles

and saliva

ACTIVE

INACTIVE

Gelled

emulsion

saliva

saliva

GEL FRACTURING dependent on gelling

agent and droplet interaction

Creamy

Thick

Rich

Smooth

Coating

What makes emulsions creamy?

20Together to the next level

26 refereed journal publications and 8 book chapters (2005-2011) by the TIFN project team

porous

TI food and

Nutrition

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Restored creaminess in

reduced fat products• Restore boundary lubrication:

• Emulsion sensitized to coalescence (increase solid fat content, adjusted emulsifier mix, OSA starch)

• Specific lubricating emulsifiers

• Reduce acidity and astringency (polyphenols)

• Restore viscosity:• Smaller droplet size

• Similar thinning behavior during oral processing

• Thickeners, compatible with saliva (polysaccharides,

resistant starch)

• Small particles (size below detection limit)

• Restore flavour:• Flavor rebalancing

• Controlled release

21

GASTRO-INTESTINAL

BEHAVIOUR OF EMULSIONS

Digestion

22

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TIFN project team:

Raymond Schipper

Anne Helbig

Man Minekus

Lex Oosterveld

Erika Silletti

Esther Bomhof,

George van Aken

Unilever

DSM

CSM

VION

FrieslandCampina

NIZO food research

TNO

WUR

B-1007: Engineered sensory and dietary functionality of dispersed fat

Engineered sensory and dietary

functionality of dispersed fat

Develop fundamental knowledge on the oro-gastro-intestinal behaviour of

food emulsion systems and how this behaviour relates to physiological responses

Structural

componentAdsorbed layer

Fat type

Droplet size

Continuous phase

Behaviour in oral-

gastro-intestinal

tract

Physiological

responses

Physiology

Oral/Gut BiochemistryPhysical chemistry

B-1007: Engineered sensory and satiating functionality of dispersed fat

Artifical mouth

BellyQuintet

pH STAT

Artificial

digestion model

TinyTIM

Pig Model

Human Studies

In vitro gastric

and intestinal

models

Animal Model

Human

subjects

In vitro,

in vivo

mouth

model

Tongue

cup

MRI

of stomach

Line up of experimental models with

increasing complexity

In silico

modeling

FUNDAMENTALS OF FAT

DIGESTION AND ABSORPTION

25

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What is the problem with fat

digestion?

Triglycerides are insoluble in water and therefore

cannot be detected and absorbed directly

• Lipases are water soluble and can only be active at

the oil/water interface → efficient lipolysis requires

large O/W interfacial areas (small droplet sizes)

• Adsorbed layer of emulsifiers and lipolytic products (fatty acids, monoglycerides) may hinder lipase activity

• For saturated C12 and longer, the lipolytic products

(fatty acids, monoglycerides and diglycerides) are

insoluble solids

• Unsaturated long chain monoglycerides (e.g. C18:1)

form cubic liquid crystals

Role of bile in the small intestine

• Bile removes emulsifiers from the interface

• Pancreatic lipase hydrolyses triglycerides into

fatty acids and sn-2 monoglycerides by lipases

• For saturated C12 and longer, the formed fatty

acids, monoglycerides and diglycerides are insoluble solids

• Unsaturated long chain monoglycerides (e.g.

C18:1) form cubic liquid crystals

Bile

micelle

Bile solubizes the

insoluble lipolytic

products into micelles

pancreatic lipase

carboxyl ester lipase

Fat digestion: main enzymatic processes

28Together to the next level

Stomach

Small

intestine

Gastric lipase

(<10%)

Pancreatic lipase

(almost complete)

Bile micelles

Portal

vein to

liver

Small intestinal

wall

lymph

chylomicron

Serum

albumin

transporter

Effect of the lymphatic route

• Long chain MUFA, SAFA and

vitamins bypass the liver

• Primarily used by the body for

energy (muscles) and stored in

adipose tissue

liver

Routing of fatty acids - overview

C11:0 and shorter

C12:0 and longer

Oleic acid

ω-6 PUFA

ω-3 PUFA

Portal vein

Lymph vessel

Main

blood

stream

ω-3 DHA

VLDL

glucose

FA

glucose

chylomicrons

serum

albumin

Nerve membrane

Muscles Adiposites

LDL

Energy

supply

Functional

lipids

Conjugated

double bonds:

CLA

Regulated stomach emptying

of nutritious liquids:Roughly constant nutrient release to the small intestine

intake

bile pancreas

Stomach

activity

duodenum jejunum ileum

Stomach

emptying

absorptive cellsPylorus

area concentration absorbable nutrients

I-cells detect nutrients(mainly duodenum, jejunum)

++--

Regulated gastric emptying at 1-2 kcal/min• Corresponds to 1440 - 2880 kcal/day, similar to the advised daily caloric intake

Regulated small intestinal

residence time (ileal brake)

intake Pylorus

bile pancreas

duodenum jejunum

L-cells detect nutrients (ileum and COLON)

Transit speedStomach

Absorptive cells

-

Ileum

• Compensates for a high caloric entry into the intestine or slow

enzymatic hydrolysis

• Normal condition: nutrients reach ileum but not colon

33

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Computer

modelingFed by: physiological literature

in vitro studies

(in vitro gastric, Simfyd, tiny TIM)

Gastric

volume

Fullness

In-silico model

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Intake(water,

protein,fat,

carbohydrate

as a function

of time)

Fundus

Corpus

Antrum Duodenum Jejunum 1

Jejunum 2

Jejunum 3 Ileum 1

Ileum 2

Ileum 5

Ileum 6 Colon

Ileum 3

Ileum 4

FFAFFA

FFA

FFA

FFA

FFA

FFA

FFA

FFA

FFA

Total

absorbable

nutrients

pylorus

Nutrient

density in

chyme

Hunger

absorption

I-cellsCCK

oxymodulin

• Potentiate glucose-stimulated insulin

secretion

• Reduce glucagon

avoid high blood sugar

oxymodulin

Insufficient calories

in my gut...

I should eat!

L-cellsPYY, GLP1,

oxymodulin

Enough calories in my stomach ... time to stop eating!

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Examples

1. Emulsions that cream in the stomach

2. Emulsions that sediment in the stomach

35

Increase fullness during eating by improving

the emulsion stability in the stomach

Bulk fat and many emulsions and are unstable in the stomach

(low pH, enzymes) and separate a fat–rich creamed layer .

Consequence: an energy poor lower phase empties fast, quickly

reducing the volume of the stomach

Effect gastric instability of an emulsion

*Marciani et al., British Journal of Nutrition

(2009), 101, 919–928

Simulation of an emulsion of 40 g

fat and 200 g water; effect of fat

floating as a creamed layer

0

1

2

3

4

5

6

7

8

0 200 400 600 800

a.u

.

time (min)

Fullness

reference

fully creamed fat layer

0

2

4

6

8

10

12

0 200 400 600 800

a.u

.

time (min)

Hunger

reference

fully creamed fat layer

• Expected to improve satiety during and shortly after the meal,

reducing meal size.

Approach: induce sedimentation in stomach

Collaboration with Alan Mackie (IFR) for in vivo testing

5 % triolein, 1 % WPI,

1 % caseinate

Full fat milk

Simulation of an emulsion of

40 g fat and 200 g water;

effect of fat sedimentation,

leading to an initial emptying of

a 25 % fat emulsion

Van Aken et al., Food Hydrocolloids (2011)

-1

0

1

2

3

4

5

6

7

8

9

0 200 400 600 800

a.u

.

time (min)

Fullness

reference

sedimented fat layer

-2

0

2

4

6

8

10

12

0 200 400 600 800

a.u

.

time (min)

Hunger

reference

sedimented fat layer

Relevance: suggestions from

experiments and simulation

Thin liquid high-calori drinks:

• Tend to be over-consumed because of quick emptying

before regulated emptying is activated. (less fullness during

the meal)

• The initially fast-emptying nutrients are quickly absorbed, do

not contribute to longer term hunger reduction.

(Semi-)solid high-calori food:

• Is emptied slowly, regulated by caloric content and slowed

down further by gastric “erosion” of food lumps

• Physiological estimation of calories in reserve in the

stomach and small intestine is more accurate.

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Challenge

• Combine the concepts and techniques

developed for sensory perception, digestion

and satiety of food emulsions to construct

highly liked food emulsions that are more

satiating

• Solutions highly dependent on product type

39

Thank you!

george.vanaken@nizo.com

41Together to the next level

george.vanaken@nizo.com

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Creating the future together