Tailoring the surface properties and flexibility of starch-based films using oil and waxes recovered from potato...

Agrofood byproducts may be exploited as a source of biomolecules suitable for developing bioplastic materials. In this work, the feasibility of using starch, oil, and waxes recovered from potato chips byproducts for films production was studied. The recovered potato starch-rich fraction (RPS) contained an amylopectin/amylose ratio of 2.3, gelatinization temperatures varying from 59 to 71 °C, and a gelatinization enthalpy of 12.5 J/g, similarly to a commercial potato starch (CPS). Despite of its spherical and oval granules identical to CPS, RPS had a more amorphous structure and gave rise to low viscous suspensions, contradicting the typical B-type polymorph crystal structure and sluggish dispersions of CPS, respectively. When used for films production, RPS originated transparent films with lower roughness and wettability than CPS-based films, but with higher stretchability. In turn, when combined with RPS and CPS, oil or waxes recovered from frying residues and potato peels, respectively, allowed to develop transparent yellowish RPS- and CPS-based films with increased surface hydrophobicity, mechanical traction resistance, elasticity, and/or plasticity. Therefore, potato chips industry byproducts revealed to have thermoplastic and hydrophobic biomolecules that can be used to efficiently develop biobased plastics with improved surface properties and flexibility, opening an opportunity for their valorization.