Starch-based films have gained attention due to the possibility of replacing, even if partially, synthetic polymers, which 
are responsible for several ecological problems.1 Due to strong interactions between starch chains, it is necessary the 
use of plasticizing to create more flexible materials.2
In this context, glycerol has been the most used plasticizer in the 
production of those films, but because of its high hygroscopicity it can lead to starch retrogradation after a long time of storage.3 Recently, Deep Eutectic Solvents (DES), which are mixtures of two or more compounds that present a 
mixture melting point lower than that of any individual component, have been evaluated as a likely plasticizer. Thus, some DES based on choline chloride with glycerol and urea, carboxylic acids and imidazole have already been 
demonstrated as good starch plasticizers.4
In this work, we studied the influence of three different DES (ChCl:Cit 1:1; Pro:Cit 1:2 and Bet:Cit 1:1) as plasticizing agents for the starch-based biofilms formulation. DES were prepared by 
stirring the components at 80 °C, for 2 h. The films were prepared following the casting method, which consists of heating a 3% aqueous solution of starch. Table 1 shows the DES synthesized herein, the molar ratio used, and the 
biofilms characterization data (thickness was measured using a digital micrometer, and transparency, a UV-Vis 
spectrometer). From the data obtained, we observed that the DES-based films were significatively thinner than the 
glycerol pattern. In addition, DES ChCl:Cit achieved the best results in terms of transparency, being more than twice greater of the film with Gly.