MICROINCAPSULAMENTO IN MATRICE ATTRAVERSO SISTEMI DI ESTRUSIONE IN ARIA

Candidato Marco Iasevoli

Matr. N06/125

Relatore Ch.mo Prof.Fabrizio Sarghini

ANNO ACCADEMICO 2012/2013

Matrix microencapsulation through air extrusion systems

Microencapsulation is the packaging of small particles of solid, liquid or gas, also know as the core, within a secondary material, also know as the shellor coating, to form small microparticles.

Spheres are usually classified in:

• Nanospheres (less than 100 nm)

• Microspheres (in the order of microns)

Protection of the active ingredients

Controlled Release

Mask unpleasant taste of certain

ingredients

Convert liquids to solids

Increase Shelf-life

Increase Bioavailability

GRAS Biocompatible Good barrier properties Cheap

Alginate in molecular terms is considered as a family of unbranched binarycopolymer of (14 linked β-D-mannuronic acid (M) and α-L-guluronic acid (G) residues.

Why Alginate?

The droplet breaks off when the gravitational force:

exceeds the surface tension induced counter force:

leading to a droplet diameter:

MEMS 2007 - 20th IEEE International Conference on Micro Electro Mechanical Systems, 21-25 January 2007

Experimental Conditions

Sodium alginate concentration (g/L)

15

Sodium Alginate flow rate (ml/minute)

0,20

Air mass flow rate (L/minute)

1

CaCl2 solutionConcentration (g/L)

20

CaCl2 solution mass flow (L/minute)

1

Surface tension (mN/m) 65

Reynolds Number (Re) 1174

Weber Numbe (We) 35

389 m

126 m

With Screen (Blue Line)

WithoutScreen (Green line)

Geometry 1 (Blue Line) Geometry 2 (Green Line)

D [4;3] 66,4 µmD [4;3] 241 µm

• Scaling-up of production is obtained by using multiple tip in parallel

Air is costless There are only alginate

beads in hardening solution Easy wash with water No clog of device

Large quantity of oil means increased costs. Oil presence in hardening solution can give

coalescence of alginate bead Washing oil needs specific product Device can clog

• Taste masking

• Color masking

• Flavour Stabilization

• Novel food

Technological

• Fortified foods

• Functional foods

• Drug delivery in food matrix

• Controlled release

Healty

• Studies on live cell (e.g. Probiotics)Analytical

Encapsulation in the food sector is becoming even more important for its many applications. Sodium alginate has been chosen as matrix material because is regarded as:

•Biocompatible•Non-toxic•Biodegradable•Cheap

Some issues related to the scale-up procedure and polydispersity of the coaxial air flow technology still need to be addressed.

Nonetheless, this technology provide to food technologists a cheap, adaptable tool and a rapid prototyping platform for studies on microencapsulation through alginate.