Justine Muller - Academia.edu (original) (raw)

Papers by Justine Muller

Materials

The massive use of synthetic plastics, in particular in the food packaging area, has a great envi... more The massive use of synthetic plastics, in particular in the food packaging area, has a great environmental impact, and alternative more ecologic materials are being required. Poly(lactic) acid (PLA) and starch have been extensively studied as potential replacements for non-degradable petrochemical polymers on the basis of their availability, adequate food contact properties and competitive cost. Nevertheless, both polymers exhibit some drawbacks for packaging uses and need to be adapted to the food packaging requirements. Starch, in particular, is very water sensitive and its film properties are heavily dependent on the moisture content, exhibiting relatively low mechanical resistance. PLA films are very brittle and offer low resistance to oxygen permeation. Their combination as blend or multilayer films could provide properties that are more adequate for packaging purposes on the basis of their complementary characteristics. The main characteristics of PLA and starch in terms of not only the barrier and mechanical properties of their films but also of their combinations, by using blending or multilayer strategies, have been analyzed, identifying components or processes that favor the polymer compatibility and the good performance of the combined materials. The properties of some blends/combinations have been discussed in comparison with those of pure polymer films.

Polymer International, 2016

Influence of plasticizers on thermal properties and crystallization behaviour of poly(lactic acid... more Influence of plasticizers on thermal properties and crystallization behaviour of poly(lactic acid) films obtained by compression moulding.

Journal of Food Engineering, 2014

The effect of incorporating different ratios of both non-heated and heated (95 ºC) buttermilk (BM... more The effect of incorporating different ratios of both non-heated and heated (95 ºC) buttermilk (BM) to corn starch (CS) films was analyzed in terms of its structural, mechanical, barrier, optical and bioactive properties. The properties of the film forming dispersions (particle size distribution, -potential and rheological behavior) were also analyzed. As the BM increased in the blend, both the average particle size and the apparent viscosity of the film forming dispersions were reduced. The low degree of compatibility between both materials resulted in heterogeneous structures, where an interpenetrated protein phase in the starch matrix was observed as a result of the protein gelation when BM was heated. This affected the mechanical and barrier properties giving rise to more resistant and extensible, and less permeable films than in non-heated BM. Only films formulated with heated BM exhibited antioxidant activity, probably due to the release of the antioxidant peptides during thermal treatment of proteins. BM did not have any effect on the growth of Listeria innocua.

Bilayer films from thermoplastic starch and cast amorphous PLA were obtained by compression mould... more Bilayer films from thermoplastic starch and cast amorphous PLA were obtained by compression moulding, incorporating or not cinnamaldehyde in the PLA layer. Films were characterized as to their microstructure and barrier, tensile and optical properties, as well as thermal behaviour, X-Ray diffraction pattern and FTIR spectra. Bilayers using semicrystalline PLA, instead of starch, were also analysed for comparison purposes. Despite the lower ratio of cast PLA sheet in the bilayer assembly (about 1/3 of the film thickness), a great improvement in tensile and water vapour barrier properties was achieved with respect to the net starch films, the films maintaining high transparency and oxygen permeability as low as starch films. When cinnamaldehyde was included in the cast PLA sheet, films became thinner due to the losses of the volatile active during processing, but the improvement in barrier properties was maintained, with lower mechanical resistance. Thermal analyses revealed diffusion of cinnamaldehyde or low molecular weight compounds from cast PLA layer to the adhered sheets (starch or semicrystalline PLA) which contributed to plasticizing the amorphous regions and affected crystallization pattern of PLA, as also revealed by the X-Ray diffraction patterns. The obtained results offer an interesting option to obtain high barrier-highly resistant active films from thermoplastic starch and amorphous PLA, including cinnamaldehyde as active compound.

Materials

The massive use of synthetic plastics, in particular in the food packaging area, has a great envi... more The massive use of synthetic plastics, in particular in the food packaging area, has a great environmental impact, and alternative more ecologic materials are being required. Poly(lactic) acid (PLA) and starch have been extensively studied as potential replacements for non-degradable petrochemical polymers on the basis of their availability, adequate food contact properties and competitive cost. Nevertheless, both polymers exhibit some drawbacks for packaging uses and need to be adapted to the food packaging requirements. Starch, in particular, is very water sensitive and its film properties are heavily dependent on the moisture content, exhibiting relatively low mechanical resistance. PLA films are very brittle and offer low resistance to oxygen permeation. Their combination as blend or multilayer films could provide properties that are more adequate for packaging purposes on the basis of their complementary characteristics. The main characteristics of PLA and starch in terms of not only the barrier and mechanical properties of their films but also of their combinations, by using blending or multilayer strategies, have been analyzed, identifying components or processes that favor the polymer compatibility and the good performance of the combined materials. The properties of some blends/combinations have been discussed in comparison with those of pure polymer films.

Polymer International, 2016

Influence of plasticizers on thermal properties and crystallization behaviour of poly(lactic acid... more Influence of plasticizers on thermal properties and crystallization behaviour of poly(lactic acid) films obtained by compression moulding.

Journal of Food Engineering, 2014

The effect of incorporating different ratios of both non-heated and heated (95 ºC) buttermilk (BM... more The effect of incorporating different ratios of both non-heated and heated (95 ºC) buttermilk (BM) to corn starch (CS) films was analyzed in terms of its structural, mechanical, barrier, optical and bioactive properties. The properties of the film forming dispersions (particle size distribution, -potential and rheological behavior) were also analyzed. As the BM increased in the blend, both the average particle size and the apparent viscosity of the film forming dispersions were reduced. The low degree of compatibility between both materials resulted in heterogeneous structures, where an interpenetrated protein phase in the starch matrix was observed as a result of the protein gelation when BM was heated. This affected the mechanical and barrier properties giving rise to more resistant and extensible, and less permeable films than in non-heated BM. Only films formulated with heated BM exhibited antioxidant activity, probably due to the release of the antioxidant peptides during thermal treatment of proteins. BM did not have any effect on the growth of Listeria innocua.

Bilayer films from thermoplastic starch and cast amorphous PLA were obtained by compression mould... more Bilayer films from thermoplastic starch and cast amorphous PLA were obtained by compression moulding, incorporating or not cinnamaldehyde in the PLA layer. Films were characterized as to their microstructure and barrier, tensile and optical properties, as well as thermal behaviour, X-Ray diffraction pattern and FTIR spectra. Bilayers using semicrystalline PLA, instead of starch, were also analysed for comparison purposes. Despite the lower ratio of cast PLA sheet in the bilayer assembly (about 1/3 of the film thickness), a great improvement in tensile and water vapour barrier properties was achieved with respect to the net starch films, the films maintaining high transparency and oxygen permeability as low as starch films. When cinnamaldehyde was included in the cast PLA sheet, films became thinner due to the losses of the volatile active during processing, but the improvement in barrier properties was maintained, with lower mechanical resistance. Thermal analyses revealed diffusion of cinnamaldehyde or low molecular weight compounds from cast PLA layer to the adhered sheets (starch or semicrystalline PLA) which contributed to plasticizing the amorphous regions and affected crystallization pattern of PLA, as also revealed by the X-Ray diffraction patterns. The obtained results offer an interesting option to obtain high barrier-highly resistant active films from thermoplastic starch and amorphous PLA, including cinnamaldehyde as active compound.