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
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