novel technique which can be used in food industry to produce high quality stable emulsion with the use of a little energy

1. By
Geethu S
2011-06-007

2. INTRODUCTION

 Emulsion is a type of colloid formed from a mixture of
two or more immiscible liquid such as water and oil
 Two phase- continuous phase and dispersed phase
 Two type- water in oil and oil in water emulsion
 Eg: egg ,cheese, milk, margarine

3. Methods of preparation of emulsion

 Stirring equipment
 Colloid mill
 Homogenizers
 Ultrasonics or microfluidizers

4. MEMBRANE EMULSIFICATION

 It’s a novel techniques for producing single and
multiple emulsions
 Introduced by Nakashima and Shimizu in 1980s in
Japan
 The dispersed phase is forced through the pores of a
microporous membrane directly into the continuous
phase by using low pressure
 Emulsified droplets are formed and detached at the
end of the pores with a drop-by-drop mechanism

5. Contd….

 Droplet detachment of the membrane surface
dependant on four main forces
• Shear
• Interfacial tension between emulsified fluids
• Inertia/pressure from the flow through the membrane
• Buoyancy
 Resulting droplet size is controlled primarily by the
choice of the membrane

6. 
Fig: Schematic diagram of ME process

8. Parameter affecting the emulsion production

Membrane parameters
 Phase parameters
 Process parameters

9. 
Membrane parameters
 Pore size
 Pore shape
 Pore size distribution
 Porosity
Wettability
 Permeability
 Thickness

10. 
Phase parameters
 Interfacial tension
 Emulsifier type and concentration
 Viscosity
 Density

11. 
Process parameters
Wall shear stress
 Transmembrane pressure
 Temperature

12. Membrane materials

 SPG membrane (.1-20μm)
 Silicon membrane
 silicon nitride microseive membrane
 Ceramic aluminium oxide membrane
 Polytetrafloroethylene membrane

13. Types of membrane emulsification

 Dead end membrane emulsification
 Cross flow membrane emulsification
 Vibrated membrane emulsification
 Rotating membrane emulsification

14. Dead end membrane emulsification

 Simplest form
 This method employs applied pressure to force the
dispersed phase through a porous membrane into the
continuous phase
 Droplets form at the pore and detach when they reach
a specific size relative to the size of the pore
 Surfactant is added to the continuous phase to stabilize
the newly formed droplets and prevent droplet
coalescence
 PTFE is used as membrane

15. 

16. Cross flow membrane emulsification

 Continuous phase to provide shear by flowing it across
the surface of the membrane
 Droplets are detached before becoming large enough to
spontaneously detach and smaller relative to the
membrane pore size

17. +


18. Vibrating membrane emulsification

 Uses vibration of the membrane (either sub sonic or
ultrasonic) to detach droplets from the membrane
 Improve the efficiency of emulsification in some
circumstances

19. Rotating membrane emulsification

 Centrifugal force will work along with the shear at the
membrane surface provided by the rotation to detach
droplets

20. Preparation of food materials

Simple emulsion
• Two main types of simple emulsion ,(o/w)
emulsions and(w/o) emulsions
• ME is suitable for preparation of large scale
w/o food emulsions
• Using SPG membranes, o/w emulsions with
liquid butter fat or sunflower oil as the
dispersed phase and a continuous phase
containing milk proteins

21. 
Multiple emulsion
 “Emulsion of emulsion”
 The primary emulsion may be produced by means of a
conventional method or by membrane emulsification
 The mild conditions of membrane emulsification are
especially useful for the second emulsification step in
order to prevent rupture of the double emulsion
droplets

22. 
Encapsulation
 Microcapsules containing viable cells (Lactobacillus
casei) were produced using the ME technique
 Stability of encapsulated cells are high

23. 
Aerated gel
 Food gels are soft solids containing a high amount of
aqueous phase
 Aerated food gels were produced recently by
membrane foaming
 Pressing the dispersed phase (gas) through the pores
of a tubular membrane into the continuous phase
 The bubbles formed are covered with surface-active
substances of the continuous phase

24. 
Industrial applications
 Suitable for large scale production, they are easy to
scale-up, by adding more membranes to a device
 Process can done in both batch and semi- continuous
process
 Product obtained from ME is very stable, for at least 6
months without the use of preservative,

25. ADVANTAGES

 Lower energy input with respect to conventional
emulsifier
 No foaming, reduced coalescence phenomenon
 Narrow droplet size distributions
 Various configurations: premix emulsification, rotating
device to reduce fouling and increase productivity

26. DRAWBACKS

 Additional resistance to mass transfer created by the
membrane
 Relatively low membrane lifetime; high replacement
cost
 Low permeation rate associated to narrow droplet size
distribution and reduced productivity
 Fouling phenomenon on the membrane surface
and/or in the pores

27. CASE STUDY


28. TITILE :Viscosity change in oil/water food emulsions
prepared using a membrane emulsification system

Done by: Y. Asano and K. Sotoyama
Objective:
 Evaluate the viscosity changes in o/w emulsion
 Study the physical properties emulsions

29. Materials and methods

 Membrane emulsification apparatus
 Materials
• For the oil phase, corn oil was used. For the water
phase, deionized water was used
• Emulsifier polyglycerol esters (PGE)
• Stabilizer carnageenan

30. 
Methodology
 Preparation of emulsion
 Before emulsification, the MPG tube was pre-soaked in
the continuous phase in an ultrasonic bath for 30 min
 The dispersion phase was delivered into the MPG tube
 The continuous phase circulated in the vessel
 The pressure of the dispersion phase was gradually
increased

31. Contd…

 Dispersion phase was emulsified into the continuous
phase by passage through the membrane
 Continued until dispersion phase concentration of 10
vol% at the emulsifying temperature of 25⁰C was
reached
 The dispersion phase volume was calculated by
measuring the total weight of the vessel
 Average droplet diameter and the droplet distribution
were measured using an image analyser system
 Viscosity by vibration viscometer

32. 

33. Contd…

 Assessment of monodispersed emulsion
 An index of monodispersion, a coefficient of dispersion
(α )
 α = Sd/Dp
 Smaller the values, the more monodispersed the
emulsions (<=.35)

34. Results and discussion

 The value of α was 0.203, so it was evident that
emulsion was monodispersed
 From the micrographs obtained directly after
emulsification and 1 month after emulsification there
were no differences between these emulsions

35. 

36. Contd..

 As the droplet size in the emulsion increased with
decreasing viscosity

37. 
Relation ship between droplet diameter and viscosity

38. CONCLUSION

 Membrane emulsification should is a very interesting
technique for the food processing industry.
 Benefits of membrane emulsion for the food processing
industry may arise from low shear properties,
especially for the preparation of double emulsions
 Another advantage of membrane emulsion is the scale-up
ability of membrane devices
 Main limitation is fouling phenomenon
 And it solved by recent process called premix ME

39. Reference

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