The purpose of this study was to obtain a biodegradable film based on polyvinyl alcohol with reduced water vapor permeability. The hydrophobic character of the films was achieved by incorporating beeswax, vegetable bio-surfactant, citric acid as a cross-linking agent, and glycerol to provide elasticity, along with the application of thermal treatment. Water vapor permeability was determined gravimetrically. The results indicated that all films produced had lower water vapor permeability compared to unmodified or untreated polyvinyl alcohol films. The barrier to water vapor varied directly with the mass of beeswax used, and the homogeneous dispersion of beeswax in the polyvinyl alcohol matrix was essential for achieving an efficient hydrophobic film. The best performing-material exhibited a water vapor permeability 5.15 times lower than that of the neat polyvinyl alcohol and 15 times higher than that of polyethylene. Considering the fact that the water vapor barrier property of neat polyvinyl alcohol was 78 times lower than that of polyethylene, the combination of beeswax, citric acid, and vegetable bio-surfactant—along with thermal treatment—can be a viable solution to reduce the hygroscopicity of polyvinyl alcohol-based films.

This study aimed to investigate bioactive poly (vinyl alcohol) (PVA) films incorporating three chemically distinct naturally phenolic additives—aronia extract (A), apple peel extract (AP), and rutin (R)—as individual functional modifiers for active packaging applications. Here, we studied how the chemical nature of these phenolic compounds influenced the physicochemical characteristics, structure, release behavior, and functional properties of the PVA matrix. The FTIR, SEM, AFM and XPS analyses revealed intermolecular interactions between the hydroxyl groups from the PVA matrix and the hydroxyl and carboxyl groups from phenolic compounds, a high degree of miscibility between them, as well as uniform dispersion of polyphenols in the PVA matrix. XRD analysis indicated the ability of phenolic compounds to change the PVA film’s crystallinity. The films showed very low permeability to castor oil and the UV-Vis light barrier property of the film modified with aronia extract was 47% higher as compared to the reference film. The phenolic compounds improved the antioxidant activity of the reference film by about 90% and inhibited the growth of Gram-positive Staphylococcus aureus. The modified films proved their functionality by keeping the quality of the butter packed for 43 days, demonstrating their potential as active packaging materials.

This study investigated the structural and functional responses of whole wheat flour (WWF) and black wheat flour (BWF) to microwave (MW) dielectric heating. MW exposure impaired gluten network stability in WWF, whereas BWF exhibited limited cohesive gluten formation, acting as an elasticity-attenuating component. FTIR and XRD analyses demonstrated significant increases in relative starch crystallinity after 220 s of MW exposure, due to Vh-type complexation. AFM confirmed pronounced increases in surface roughness (BWF: S_a +39%, S_q +41%; WWF: S_a +42%, S_q +30%). Protein secondary structure deconvolution confirmed thermal denaturation rather than beneficial ordering: native β-sheets decreased (WWF: 37.04% to 32.68%; BWF: 37.97% to 31.49%), while β-turns increased (WWF: 22.32% to 30.14%). Water contact angle measurements showed reduced surface hydrophobicity (−19.20% in WWF, −22.70% in BWF). Thiol-disulfide (-SH/-SS) determinations highlighted different molecular mechanisms: WWF underwent intensive disulfide cross-linking (+419.6%), whereas BWF preserved free thiols (+75.5%) due to protective phenolic–protein complexation. Granular thermal damage increased in vitro enzymatic amylolysis, significantly elevating the amount of rapidly digestible starch (RDS) and estimated glycemic index (eGI). Overall, MW processing preferentially remodeled protein networks in WWF while predominantly altering starch matrix morphology in BWF, providing key insights into the dielectric thermal processing of conventional and pigmented wheat flours.

The aim of this study was to establish the optimal content of beeswax (BW) that can be added to a polyvinyl alcohol (PVA) matrix in order to obtain the maximum barrier effect against water vapor. The beeswax, ranging from 0 wt.% to 17.79 wt.%, induced surface heterogeneity and increased roughness. Although migration in all the studied simulants exceeded the limit of 10 mg/dm²/24 h, of all the prepared films, the most efficient ones were found to be those containing 12.63–15.5 wt.% beeswax, which exhibited 50% lower solubility in aqueous, acidic, alcoholic, and fatty food simulants than did neat PVA. The disadvantage is that the tensile strength of the films is 16 times less than PE and 8 times less than unchanged PVA when 12.63–17.79 wt.% BW is added. The water vapor transmission rate was 24 times lower than that of neat PVA and only 2 times higher than that of polyethylene (PE). Additionally, the results confirmed the separation of PVA and beeswax phases with the addition of more than 15.5 wt.% beeswax. BW incorporation modifies the high-temperature degradation pathway of PVA, leading to more substantial mass losses, but without compromising the overall thermal stability of the films. This is a preliminary study that established that the maximum hydrophobic effect is obtained at a beeswax content of 15.29 wt%. The preparation recipe must be optimized by testing with other hydrophobic agents that reduce migration in simulants and increase the barrier properties, and nanoparticles that increase mechanical strength.