Effect of Egg-Coating Material Properties by Blending Cassava Starch with Methyl Celluloses and Waxes on Egg Quality

Egg shelf life can be extended using varied proportions of polyvinyl alcohol/chitosan composite coatings

Using biopolymers in the form of edible coating as egg eco-friendly packaging is a progressive approach. The blending of biopolymers is one of the procedures for overcoming mechanical weakness and benefiting from their maximum synergistic effect. Aiming to determine the relative ratios of chitosan (CH 4 w/v%) and polyvinyl alcohol (PVA 5 w/v%) in the composition of blended coatings, an experiment was conducted with six treatments (r = 3) including different ratios of CH/PVA (0:0; control, 100:0, 75:25, 50:50, 25:75, and 0:100) wt% in a period of 4 weeks of egg storage at ambient temperature, emphasizing eggshell barrier properties. Based on the eggshell analysis result, SEM images and FTIR spectra demonstrated that the components were firmly integrated into the blended coatings as well as had more intertwined than their pure ones, which was also reflected in the evaluation results of their internal quality parameters. In addition, the results showed that by enhancing the ratio of polyvinyl alcohol from 25 to 75 wt%, the blended coating barrier efficiency was relatively improved (p < .05). Meanwhile, the lowest percentage of weight loss (0.57 ± 0.08%), pH value of albumin (8.30 ± 0.04), the highest values of Haugh unit (61.00 ± 0.07), yolk index (0.37 ± 0.02) were observed in eggs coated with CH/PVA 25:75 wt%. But there was no difference in 50 or 70 wt% PVA significantly. Therefore, the CH/PVA blended coatings containing around 50-75 wt% PVA, as egg biodegradable packaging, can be used to extend the shelf life for 2-3 weeks at ambient temperature.

Modified Poly(Lactic Acid) Epoxy Resin Using Chitosan for Reactive Blending with Epoxidized Natural Rubber: Analysis of Annealing Time

Poly(lactic acid) was melt-blended with epoxy resin without hardener and chitosan (CTS) to prepare modified PLA (PLAEC). Epoxy resin 5% and CTS 1–20% (wt/wt) were incorporated into PLA during melt mixing. PLAEC was melt-blended with an epoxidized natural rubber (ENR) 80/20 wt. The PLAEC CTS 1% blended with ENR (PLAEC1/ENR) showed a high tensile strength (30 MPa) and elongation at break (7%). The annealing process at 80 °C for 0–15 min maintained a tensile strength of approximately 30 MPa. SEM images of the PLAE/ENR blend showed phase inversion from co-continuous to ENR particle dispersion in the PLA matrix with the addition of CTS, whereas the annealing time reduced the hole sizes of the extracted ENR phase due to the shrinkage of PLA by crystallization. Thermal properties were observed by DSC and a Vicat softening test. The annealing process increased the crystallinity and Vicat softening temperature of the PLAEC1/ENR blend. Reactions of −COOH/epoxy groups and epoxy/−NH₂ groups occurred during PLAE and PLAEC preparation, respectively. FTIR confirmed the reaction between the −NH₂ groups of CTS in PLAEC and the epoxy groups of ENR. This reaction increased the mechanical properties, while the annealing process improved the morphology and thermal properties of the blend.