No abstract

In this work, two formulations of pectin/cellulose nanocrystals/glycerol nanocomposites were employed as packaging to extend storage life of strawberries. The effects of incorporating cellulose nanocrystals extracted from bleached Kraft wood pulp on the mechanical, thermal, and barrier properties of pectin-based nanocomposites were evaluated. Nanocomposite films with different filler levels of cellulose nanocrystals (1, 2, 4 and 8% w/w) were prepared by casting. Compared with the neat film of pectin, improvements in the mechanical properties of the nanocomposites were observed, but these films became fragile. To improve the film flexibility, glycerol was added as a plasticizer and then new variations in the mechanical, thermal, and barrier properties of these nanocomposites were evaluated. The effects of nanocomposite films on storability of strawberries were compared with Poly vinyl chloride packaging films. The Poly vinyl chloride film and the nanocomposites showed similar behavior regarding weight loss by the strawberries, especially in the initial days of storage. The results show that pectin/cellulose nanocrystals/glycerol nanocomposites could be considered as a viable packaging alternative for replaced the Poly vinyl cloride film.

No abstract

In this work, nine different types of edible coating based on pectin, cellulose nanocrystals, glycerol, and essential oil of lemongrass were prepared and used to coat strawberries with a film formed directly on the surface of the coated fruit. The effects of the different edible coatings on refrigerated fruits in terms of weight loss, titratable acidity, total soluble solids, pH, and anthocyanin content was evaluated after 2 days, 4 days, 6 days, and 8 days of storage. Application of the edible coatings reduced the weight loss of the coated strawberries and the anthocyanin content. The total soluble solids content of or uncoated fruit increase more markedly than that of coated fruit. In contrast, pH was maintained for both coated and uncoated strawberries. The edible coatings were effective in minimizing of the weight loss, without worsening the physical chemistry attributes. The treatments T5 and T9 presented the best results.

Flaxseed gum (FG)-based films were developed with the addition of glycerol as a plasticizer and glutaraldehyde as a crosslinking agent. HCl was added to improve crosslinking and decrease the hydrophilicity of the matrix. Different cellulose nanocrystal (CN) amounts were used as reinforcements in the optimum FG formulation. The crosslinking process at pH 3.5 led to a lower solubility of FG in water (from 100% to 53%) and an increase in thermal stability (from 160 ºC to 209 ºC). FTIR analysis confirmed a reduction in the-OH band due to crosslinking between the hydroxyl groups of FG. A diffuse diffraction pattern was observed for all FG films. The addition of 4% w/w of CN contributed to reduction of water solubility (from 53% to 20.8%) and absorption (from 21.9% to 6.8%). Finally, an improvement was observed in the tensile mechanical properties in the nanocomposites, showing satisfactory results for the proposed formulations, mainly with 8% w/w of CN added to the matrix. Overall, this study demonstrated that FG/CN nanocomposites are promising materials to be use as a sustainable biopolymer for application as bioplastics.