Industrial Use of Oil Cakes for Material Applications - The Economic Utilisation of Food Co-Products - page 164

Table 7.14 Mineralisation of protein injected specimens (ISi) and
thermomoulded films (TFi). IC: Inorganic carbon dissolved;
Inh.ISi: Inhibitor of sample ISi; Inh.TFi: Inhibitor of Sample Tfi.

Time (days) IS1 IS2 Inh.IS1 TF1 TF2 Inh.TFi Cellulose

d n 9 r 3 n g | 5

27 71.8% 64.7% 78.5% 65.2% 55.5% 75.5% 67.5%

41 74.8% 67.6% 81.2% 68.3% 58.6% 78.0% 70.4%

CO 2 þ IC 75.5% 68.2% 81.6% 70.0% 59.0% 78.5% 71.1%

Average 71.8% - 64.5% - -

SD 5.2% - 7.7% - -

d y y f n n 3 .

Biodegradability of sunflower protein-based materials has also been tested in
standardised liquid conditions EN 13432 (Table 7.14). Injected and thermo-
moulded samples are ranged, respectively, as easily biodegradable and inter-
mediately biodegradable, with final mineralisation rates of 71.8% and 64.5%
with no inhibition effect of these materials on the microbial population.
Another aspect is the life-cycle assessment of this type of composite.
Unfortunately, the LCA focus has been made on bioplastics such as PLA, 70
and not on natural biocomposites. However, some insight has been presented in
a recent evaluation by the VEGEPLAST s company. Carbon balance (Bilan
Carbone s from the French environmental agency ADEME) of this cereal-
based material showed that the use of regional crops and basic thermomech-
anical processes gives a low CO 2 emission equivalent to 0.76 tons per ton, lower
than all conventional plastics. SFOC-based materials, being transformed
similarly, should then present almost the same benefit balance.

Conclusion
Oilseed proteins do possess interesting physical and chemical properties for
nonfood applications especially in the field of biobased materials.
Resources are huge and a complete nonfood culture could be more
intensively developed in fallow lands, as oil is a promising biochemical for fuel
and lubricant applications.
Unfortunately, if soy proteins are clearly identified and used industrially
(mainly for food processes), industrial extraction of proteins from other crops
(i.e. sunflower, rapeseed, linseed) is still in development. This is the main brake
on the industrial use of oil cakes, as a better understanding of proteins real
potential is needed. Their complicated behaviour under shear and heat,
involving a broad range of secondary interactions and covalent crosslinking, 17
is not yet really controlled, yet shows great promise. Protein-based adhesive
and materials have already showed some particularly interesting properties in
composites and particle boards. 46-48
Thermomechanical transformation of raw oil cakes (as shown with the
example of sunflower oil cake) is a promising process due to:

the occurrence of lignocellulosic fibres avoids the complete coagulation of
proteins and facilitates processes like extrusion or injection moulding;