Milk whey (MW) represents the major by-product of cheese industry. One possibility to recycle the MW wastes is the use of their globular proteins (MWPs) as a polymer source for the production of biodegradable plastic materials. MWP-based films are usually obtained by protein heat treatment in the presence of glycerol (GLY) as plasticizer at pH 7, a method which would require commercially high costing process. In this work it was exploited the possibility to produce manageable MW-derived biomaterials without any heat-treatment but under alkaline conditions. Our results demonstrated that the casting at pH 12 of the unheated MWP film forming solutions (FFSs), containing either 40% or 50% GLY, led to produce more resistant and flexible biomaterials than the ones obtained at pH 7. Also film transparency was observed significantly improved, being lower in the samples obtained at alkaline pH without MWP heating and with higher GLY concentrations. Finally, moisture content decreased with the reduction of GLY content, both in heated and unheated MWP-based films, whereas water uptake of the different films prepared at pH 12 did not significantly change.
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Considering the nice properties of your films ("hydrocolloid films with higher flexibility and transparency") would it be possible to investigate applications other than food packaging, possibly in medical applications?
I would suggest, as examples, drug release, cell incapsulation, or membranes....
what about the diffusivity properties of the obtained film? I think that it is an important property for food packaging
Many thanks for your interest. The diffusivity property of bioplastics is a very important issue. We are going to take it into account by entrapting some bioactive molecules in order to evaluate their release from the film protein matrix.