Self-Assembled Pullulan–Silica Oxygen Barrier Hybrid Coatings for Food Packaging Applications

Abstract

The scope of this study encompassed the evaluation of pullulan as a suitable biopolymer for the development of oxygen barrier coatings to be applied on poly(ethylene terephthalate) (PET), especially for food packaging applications. To enhance the oxygen barrier properties of the organic phase (pullulan) even at high relative humidity values, an inorganic phase (silica), obtained through in situ polymerization, was also utilized to obtain hybrid coatings via the sol-gel technique. Transmission electron microscopy (TEM) images and Fourier transform infrared (FT-IR) spectra showed that mixing the two phases yielded a three-dimensional hybrid network formed by self-assembly and mediated by the occurrence of new hydrogen-bond interactions at the intermolecular level, although the formation of new covalent bonds could not be excluded. The deposition of the hybrid coatings decreased the oxygen transmission rate (OTR) of the plastic substrate by up to 2 orders of magnitude under dry conditions. The best performance throughout the scanned humidity range (0%-80% relative humidity) was obtained for the formulation with the lowest amount of silica (that is, an organic/inorganic ratio equal to 3).

Block copolymer–nanoparticle composites: Structure, functional properties, and processing

“…For example, in food packaging, preventing fats and vitamins from oxidation is essential and can be accomplished by hindering oxygen transport through packaging films [241]. NP-containing polymer composites are thus suitable for food packaging because the incorporation of NPs in the polymer can make the diffusion paths (channels) more tortuous [242].…”

Microfibrillated cellulose (MFC): pullulan bionanocomposite films

“…A first characteristic band at *3,300 cm -1 for both polymers is assigned to the stretching vibration of -OH groups involved in the formation of hydrogen bonds at the intra-and intermolecular level (Vieira et al 2011;Farris et al 2012). …”

Pullulan Encapsulation of Labile Biomolecules to Give Stable Bioassay Tablets

“…[6a,b, 7] The filmforming property of pullulan has been utilized in some unique applications in the pharmaceutical and food industries, such as breath fresheners and food additives. [7,9] In addition, pullulan has been shown to preserve the viability of bacteria under various storage conditions. [7,9] In addition, pullulan has been shown to preserve the viability of bacteria under various storage conditions.…”

“…As shown in Figure 3, AChE stored in solution at room temperature became completely inactive within 3 days. [7,9] In theory, an antioxidant could be used to prevent the oxidation of IDA during storage at room temperature. In sharp contrast, both AChE and IDA in tablet form remained fully active for at least 2 months when stored at room temperature.…”