Relevance of genipin networking on rheological, physical, and mechanical properties of starch-based formulations.

The small amount of proteins in starch-rich food industry byproducts can be an advantage to crosslink with genipin and tailor the performance of biobased films. In this work, genipin was combined with non- purified starch recovered from industrial potato washing slurries and used for films production. Starch recovered from potato washing slurries contained 0.75% protein, 2 times higher than starch directly obtained from potato and 6 times higher than the commercial one. Starch protein-genipin networks were formed with 0.05% and 0.10% genipin, gelatinized at 75 °C and 95 °C in presence of 30% glycerol. Bluish colored films were obtained in all conditions, with the higher surface roughness (Ra, 1.22 µm), stretchability (elongation, 31%), and hydrophobicity (water contact angle, 127°) for 0.10% genipin and starch gelatinized at 75 °C. Therefore, starch-rich byproducts, when combined with genipin, are promising for surpassing the starch-based films hydrophilicity and mechanical fragilities while providing light barrier properties.

Coffee silverskin and starch-rich potato washing slurries as raw materials for elastic, antioxidant, and UV-protective biobased films.

Food processing wastes together with the perishable foodstuff loss promote environmental and societal concerns. Food byproducts can have value as a source of functional molecules for developing active packaging without food waste, under a circular economy. Nevertheless, the often-associated extraction/chemical processes compromise the sustainability of food byproducts reusability. In this work, coffee silverskin (CS) and starch, recovered from coffee roasting and potato industries, respectively, were together gelatinized to form in-situ films. Targeting to fit with the food application requirements, it is important to understand the influence of crude CS amount (1%, 5%, and 10% w/w of dry starch weight) on potato starch-based film properties. CS conferred a brownish coloration to the films, maintaining their transparency. The films colour intensity, antioxidant activity, and water tolerance were directly related with the CS dosage. Moreover, as high the CS amount, higher the elasticity, stretchability, and UV radiation absorption of the pristine films. These data emphasized that CS molecules extracted during gelatinization prevented the starch-starch hydrogen bonding and conferred functional and barrier properties. Overall, adding crude CS during potato starch gelatinization revealed to be an efficient strategy to tune the performance of potato starch-based films, opening an opportunity for valorising coffee roasting and potato byproducts.

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

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.

Biocompatible chitosan-based composites with properties suitable for hyperthermia therapy.

Sustainably made, flexible and biocompatible composites, having environmentally friendly compositions and multifunctional capabilities, are promising materials for several emerging biomedical applications. Here, the development of flexible and multifunctional chitosan-based bionanocomposites with a mixed reduced graphene oxide-iron oxide (rGO-Fe3-xO4) filler is described. The filler is prepared by one-pot synthesis, ensuring good dispersibility of the Fe3-xO4 nanoparticles and rGO within the chitosan matrix during solvent casting. The resulting bionanocomposites present superparamagnetic response at room temperature. The antioxidant activity is 9 times higher than that of pristine chitosan. The mechanical properties of the films can be tuned from elastic (∼8 MPa) chitosan films to stiff (∼285 MPa) bionanocomposite films with 50% filler. The magnetic hyperthermia tests showed a temperature increase of 40 °C in 45 s for the 50% rGO-Fe3-xO4 film. Furthermore, the composites have no cytotoxicity to the nontumorigenic (HaCat) cell line, which confirms their biocompatibility and highlights the potential of these materials for biomedical applications, such as hyperthermia treatments.