Polyphenols represent a highly abundant group of plant-derived natural compounds, characterized by remarkable structural diversity and potent antioxidant activity. Based on their chemical structures, polyphenols are broadly categorized into flavonoids, phenolic acids, stilbenes, tannins and lignans. Among these polyphenolic groups, tannins stand out for their large and complex polyphenolic frameworks and strong metal-chelating abilities. Tannic acid, a well-known hydrolyzable tannin, is one of the most extensively utilized polyphenols because of its dense phenolic composition, strong metal-chelating ability and capacity to form diverse non-covalent interactions. This review highlights recent advancements and applications of tannic acid-based micro- and nano-formulations, with particular emphasis on their roles in emulsion stabilization, enhancement of UV-barrier properties and food safety sensor applications.

We investigated the effectiveness of plant-based bio-additives – rhubarb, lingonberry, and blueberry (0.1–1%) – as natural UV absorbers in biodegradable polymers polylactide (PLA) and polycaprolactone (PCL). A novelty of this work is the direct use of plant-based raw materials as UV absorbers in polymers. We performed Fourier transformed infrared spectroscopy (FT-IR) and UV-Vis analysis of the bio-additives, determined the ultraviolet protection factor (UPF) for the polymer samples, and evaluated their physicochemical properties (structural changes, colour, hardness, surface energy) after weathering (PLA) and thermo-oxidative (PCL) aging. Spectroscopic tests confirmed the presence of UV-A/UV-B-absorbing chromophores in the additives. Samples with 1% berries had excellent UV protection (UPF 40–50+), while PLA and PCL containing 1% rhubarb had lower UPF values (around 22), indicating good UV blocking properties. After aging, PLA-containing berries showed a significantly lower carbonyl index (CI), indicating reduced photodegradation. For PCL with lingonberry, this additive gave the greatest reduction in thermo-oxidative degradation (lowest CI). All plant additives increased material hardness by acting as nucleating agents; they increased the crystallinity of polyester, and aging further strengthened this effect. Bio-additives, especially berries, can increase the hardness and UV resistance of polymers and limit material aging. These polymer compositions are suitable for packaging materials.

This study investigates the interaction between poly(butylene adipate-co-terephthalate) (PBAT) and amber powdered waste (AbW) from jewelry at different filler concentrations (0, 1, 2.5, and 5 wt%) obtained via melt mixing in a corotating twin screw extruder. The resulting materials were pelletized and processed using two techniques: 1) cast film extrusion and 2) injection molding. The shaped specimens exhibited excellent interfacial adhesion. Thermal behavior, as assessed by Vicat softening temperature (VST), differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), showed minimal variation among the composites. Despite similar melt flow rate (MFR) values among the samples, the incorporation of AbW affected the behavior of the polymer during cast film extrusion. Consequently, the composite films exhibited lower tensile mechanical parameters (tensile strength, Young’s modulus, stress and strain at break) compared to the neat PBAT film. In turn, the injection molded composites showed improved tensile, flexural, and impact parameters compared to their neat counterpart. Additionally, a slight decrease in water contact angle (WCA) suggested increased surface hydrophilicity of the extruded films. These findings demonstrate the potential of AbW as an additive for biopolymer composites with enhanced mechanical performance. The increased surface hydrophilicity is particularly relevant for applications targeting biocompatibility and biodegradability.

In this study, a new plastic film with antiviral and antibacterial properties was developed using modified cassava starch with glycidyltrimethylammonium chloride (GTMAC) and reinforced by crystalline nanocellulose (CNC), called Q-CS/CNC. For comparison, a control film (Q-CS) was produced without the addition of CNC. Elemental analysis revealed a degree of substitution (DS) of 0.552, indicating the replacement of the OH groups of starch by the NR₄⁺ groups of GTMAC during the quaternization reaction. The addition of CNC resulted in significant increases (p < 0.05) of 38.9, 38.2, and 43.1% in thickness, opacity, and water vapor permeability measurements, respectively, compared to Q-CS. Incorporating CNC also contributed to an increase of 43.6% in tensile strength and 109% in stiffness but slightly decreased thermal stability. The Q-CS/CNC film demonstrated efficacy by inactivating 99% of the coronavirus in 1 min and inhibiting the growth of Staphylococcus aureus and Escherichia coli. This action is attributed to the electrostatic interaction of quaternary amino groups, grafted onto starch, with the phospholipid membrane of microorganisms, resulting in the inactivation of these microorganisms. Therefore, these results highlight the potential use of Q-CS/CNC film as antimicrobial packaging, especially against coronavirus.

Biocomposites have recently received more attention because of raising environmental awareness and the drive toward sustainable technologies. The most common biodegradable polymer is poly(lactic acid) (PLA), which has an excellent balance of physical and rheological properties, but there is some limit to its usage. PLA properties can be improved by adding different types of fibers or fillers that come from agricultural waste. In this study, corn cob and lavender stem were used to reinforce PLA without any coupling agent, and the properties of the composites were investigated. The melt flow rate (MFR) values decreased with the corn cob content and increased with the addition of lavender stem. Mechanical tests showed that the tensile and flexural modulus of the composites increased and the strengths decreased with the reinforcement material content. The rigidness of PLA slightly decreased with the addition of fillers. There was no significant effect on the thermal properties. The unremarkable improvement of the reinforcement was due to the lack of appropriate adhesion of the two phases. The structure of the compounds was found to be homogenous on the scanning electron microscopy (SEM) micrographs. The incorporation of corn cob and lavender stem can reduce the production cost of materials.