Nano and Microstructure design

Anne-Marie Hermansson

• understand food structures • control food structures

• product development • process development

• new measurement tools • predictive science

Nano and Microstructure design

Structural levels

Molecules

Supermolecular

assemblies

Gels and

interfacial structures

Mixed structures

Anne-Marie Hermansson

Myosin molecules on a mica surface

0.2 mm

Hermansson and Jordansson

Myosin filaments

Head to head interactions of myosin molecules

Hermansson and Jordansson

Myosin gels

1 mm

pH 6.0 and 0.6M KCl pH 5.5 and 0.25M KCl

Hermannson and Langton 1986

Macroscopy 2x10-2-1x10-4m

bulk specimen

Light microscopy 2x10-3 - 5x10-7m

smears, cryosections, plastic sections

CLSM 2x10-3 - 5x10-7m

bulk specimen, cryosections, dynamic structures

Scanning electron microscopy

CSEM; LVSEM; ESEM 2x10-3 - 5x10-9m

critical point drying, cryo-SEM

uncoated wet samples, dynamic structures

Transmission electron microscopy 2x10-5 - 5x10-9m

thin-sectioning, negative staining,

freeze-etching, mica-technique, cryo-TEM

Microstructure characterisation

Biopolymer gels

structural aspects and properties

??

?? ?

Molecular properties

Junction zones

Gel properties

Network Morphology

Amylose Superabsorbent Sepharose

100 nm 200 nm 50 nm

Gels – length scales

Hermansson A.M. , Kidman S and Altskär A

Mass transport rate

1 10 100 1000

?

Design for diffusion and flow

Diffusion

Flow

Pore size / nm

Modification by aggregation

κ-carrageenan in 100 mM KCl

Gel formation by quenching Gel formation by slow cooling

Kidman and Hermansson

Lorén N, Nydén M, Hagman J and Hermansson A.M

Nano structure design of diffusion

Pressure drop as a function of pore size

100 nm 100 nm

The importance of structure related mass transport

properties

Nanoscaled 3D microstructure – Sepharose Gel

1000 nm

Mathematical identification of the 3D microstructure from TEM micrographs

Nisslert, Lorén, Kvarnström, Nydén, Rudemo (2007) J. Microscopy

A LATTICE-BOLZMANN FRAMEWORK FOR DIFFUSION AND

FLOW

Predictable mass transport in soft materials

and a detailed understanding of flows and

diffusion in heterogenous structures

Tobias Gebäck, Alexey Heintz, Jenny Jonasson, Marie Skepö,

Magnus Nydén

Compare diffusion and flow streamlines in a gel structure

Confinements – structure formation in restricted volumes

Mayonnaise Cream cheese

Phase separated biopolymer structures

25 μm

?

Sophia Wassén, Niklas Lorén and Anne-Marie Hermansson

Effect of confinement

Droplet size 4% Gelatin - 6% Maltod. Quenching to 20°C

25 µm 25 µm

(b) Diam. ~130 μm

Bulk Discontinuous

25 µm

(d) (d) Diam. ~10 and 15 μm

25 µm

(c) (c) Diam. ~20 μm

25 µm

Different microstructures in small droplets

Janus-like Core-shell

Decreasing diameter

(a)

Sophia Wassén, Niklas Lorén and Anne-Marie Hermansson

30 s at 40 °C

50 μm

(a)

100 s at 40 °C

(b)

Smaller droplets were seen to phase separate at higher temperatures

30 s at 20°C

(c)

100 s at 20°C

(d)

Effect of confinement

Initiation of phase separation 4% Gelatin - 6% Maltod. 5 min holding time at 40 °C

Time

Sophia Wassén, Niklas Lorén and Anne-Marie Hermansson

4% gelatin LH and 7.3% maltodextrin

90°C/min

55°C/min

5°C/min

S. Wassén, E.Rondeau, K. Sott, N. Lorén, P. Fischer and A.M. Hermansson. Food Hydrocolloids 2011

A faster cooling rate results in smaller domain sizes

Kinetics of structure formation

4 w/w% gelatin 7.3 w/w% maltodextrin

Quenched from 70°C to 20°C

4 w/w% gelatin 6 w/w% maltodextrin

Quenched from 70°C to 20°C

50μm 50μm

Heterogeneous systems

Hagman, Wassen, Lorén, Hermansson (2010).

• Development of new methods for controlled wetting

and swelling experiments during observation of SEM

cooled Cu cylinder with

condensed water

sample

Anna Jansson, Stefan Gustafsson, Anne-Marie Hermansson and Eva Olsson

Controlled wetting of individual cellulose

fibres

Water

droplet

Cu cylinder

(cooled)

Cellulose fibre

Nanomanipulator

Piezoelectric tube

Electron beam

10 µm

Phase separated biopolymer film

In situ ESEM studies of water transport in cellulose

films for controlled release of drugs

Anna Jansson, Stefan Gustafsson, Anne-Marie Hermansson and Eva Olsson

Structure management

Microstructure characterisation

• Different microscopy techniques (LM, CLSM, TEM))

• Length scales

• Time scales

• Image analysis

Measurements under dynamic conditions

• Structure formation

• Water uptake

• Structure break-down

Structure breakdown directly studied in the CLSM

Fresh cheese

0.1

0

F (N)

120 40 80 160 sec

500mm

0.6mm extension

Process control

Co

olin

g tu

be

Co

olin

g tu

be

Co

olin

g tu

be

Emulsification

(Mixing) HP

pump Pasteur Precooling Pin

mixer

Storage (after 2

weeks)

The art of Food Technology

Co

olin

g tu

be

Co

olin

g tu

be

Co

olin

g tu

be

Emulsification

(Mixing)

HP

pump Pasteur Pre-cooling Pin

mixer

Storage

(after 2

weeks)

1mm equals 13,5 m m 1mm equals 5 m m

Tillverkning av Lätt och Lagom

Variables

• Fat phase

- vegetable / milk fat

- crystallisation kinetics

• Water phase

- protein / starch

- pH

- holding time

- temperature

• Process

- flowrate

- temperatures

• Storage time

Ekstedt et al

-

- - - Safety

Expectations

Nutritional aspects Function

Product quality

What is healthy?

property control

Process

Raw materials

Consumer attitudes

Nano and Microstructure Design

Composition