Physical properties of kafirin films

Enviropak final meeting

Mats StadingKatarina NilssonSusanna Edrud

Siw KidmanAnnika AltskärPaola Olofsson

Maria Petersson

SIK – The Swedish Institute for Food and Biotechnology Structure and Material Design

Göteborg, Sweden

Samples

• Kafirin from CSIR large batch• Defatted zein from Sigma• Cast and thermoplastic films (from

Sammy)• Plasticizer/protein: 0, 0.2, 0.3 and 0.4

Characterization

• Fracture strength (E, b, b)

• Thermomechanical properties, DMA (G*, Tg)

• Barrier properties (WVP, OP)• Moisture content• Microstructure (LM, CLSM, TEM)

Plasticizers testedPlasticizer/protein

Plasticizer

0.01 0.05 0.10 0.20 0.30 0.40

Glycerol

PEG

PPG

Lactic acid (LA)

Gly/PEG (1:3, 1:1, 3:1)

Gly/PPG (1:3, 1:1, 3:1)

Gly/PEG/LA (1:1:1)

Gly/PPG/LA (1:1:1)

Acetyl. monoglyceride EPZ

Acetyl. monoglyceride Acetem

Castor-oil derivate

Diethanolamine

Tyrosine

Tryptophane

Oleic acid

Palmitic acid

0

5

10

15

20

25

30

35

0.2 0.3 0.4

Stress at break

Ethanol

Plasticizer/kafirin

Acetic acidb [MPa]

0

10

20

30

40

50

60

0.2 0.3 0.4

Strain at break

Ethanol

Plasticizer/kafirin

Acetic acid

b [MPa]

0

2

4

6

8

10

12

14

16

18

20

0.2 0.3 0.4

Moisture content

Ethanol

Plasticizer/kafirin

Acetic acidMC [% w/w]

0

10

20

30

40

50

60

70

0.2 0.3 0.4

Plasticizer/protein

Tg

[°C

]

Glass transition temperature ofkafirin and zein films

Thermoplastic zeinfilms from IMBC

PEG

PEG

LA

Kafirin

Zein

Glycerol/PEG/la1:1:1

0

5

10

15

20

0.2 0.3 0.4

Water Vapour PermeabilityComparison with other materials

AmyloseAmylopectin

glycerol

Plasticizer/kafirin

WVP [g mm/m²h kPa]

0.4 0.48 0.83

Whey protein

glycerol

sorbitol

EVOHLDPE

0

20

40

60

80

100

120

140

0.2 0.3 0.4

Oxygen Permeability

Plasticizer/kafirin

OP [cm³ m/m² d kPa]

UP kafirinpreparation

AmyloseAmylopectin

glycerol

0.4 0.3 0.83

Whey protein

glycerol

sorbitol

LDPE1900

EVOH

Ethylene Permeability

0.001

2

4

11 10

0

2

4

6

8

10

12

Pureprotein

+10% lipid +20% lipid +30% lipid +40% lipid

Eth

ylen

e tr

ansm

issi

on

MS

uni

ts x

10

-11

Thermoplastic zein films

25% PEG400, 50rpm, 60°C, 600s

Fine structures of zein films

Micropores

Processing temperatures (60°C, 70°C, 80°C) do not seem to change the microstructure of the thermoplastic films

11mm

11mm

0.10.1mm

60°C

Observations

Bigger micropores at higher processing temperature

Less striated structure at higher processing temperature more even melting

No microstructural difference between lauric acid and PEG plasticization

Thermoplastic kafirin films80°C

2020mm 2020mm

11mm11mm