Corn starch melt-processing in the presence of a commonly used plasticizer mixture (water/glycerol)
and a non-conventional alternative (alginate/glycerol) was evaluated. All assayed formulations were
successfully processed by melt-mixing and injected in circular probes. It was determined that all samples
presented a typical viscoelastic behavior, observing a decrease in storage and loss modulus with
water and alginate concentration, which facilitated samples processability. Concerning to thermal stability,
it was not affected neither for water nor alginate presence. From injected probes, flexible films
were obtained by thermo-compression. Films with the highest assayed water content presented a sticky
appearance, whereas those containing alginate were non-tacky. Plasticizing action of water and alginate
was evidenced by the occurrence of homogeneous fracture surfaces, without the presence of unmelted
starch granules. Besides, the shift of glass transition temperature to lower values also corroborated the
plasticizing effect of both additives. In conclusion, obtained results demonstrated the well-plasticizing
action of sodium alginate on starch matrix, turning this additive into a promissory alternative to replace
water during melt-processing of thermoplastic corn-starch.