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Chemical modification of chitosan becomes a promising strategic to improve its physicochemical and biological properties which potentially applied in biomedical application. This work aimed to evaluate the effect of several radical initiator types on antioxidant and antibacterial activities of chitosan-ferulic acid conjugates. The conjugation reaction system used formic acid/H2O2, t-butanol/H2O2, oxalic acid/H2O2, ascorbic acid/H2O2, citric acid/H2O2, and malonic acid/H2O2 as redox pairs. The physicochemical properties of conjugate products were studied based on the total phenolic content, morphology image, thermal behavior, and infra red analyses. All conjugate products showed the improvement of the antioxidant activities. Furthermore, conjugation reaction employing many types of radical initiator system enhanced the total phenolic content of chitosan. [ABSTRACT FROM AUTHOR]

In this study, bioplastics with antioxidant and UV protection properties based on tannin and PVA were created for packaging uses. Using a hot water extraction method at various extraction temperatures (60–100 °C), tannins were removed from the bark of Acacia mangium. Tannins with the best antioxidant activity were extracted at 80 °C. In order to create bioplastic formulations (PVA/Tannins), the extract is then employed. The non-heating bioplastic method's preparation (M3) stage produced the highest levels of antioxidant activity. Therefore, subsequent tests were conducted using the non-heating method (M3). On the opacity, UV protective activity, antioxidant capacity, mechanical strength, thermal stability, and water vapor permeability of the resultant bioplastics, the impact of tannin concentration (0.1–0.5 g) was examined. The findings of the experiments demonstrate that PVA/Tannin bioplastics are less transparent than pure PVA. The PVA/tannin bioplastics that are formed, on the whole, show strong antioxidant and UV protection action. Comparing PVA/Tannin bioplastics to pure PVA also revealed a small improvement in thermal stability and tensile strength. In PVA bioplastics with resistant tannins, moisture content was marginally greater even at low tannin concentrations (0.1 g). Based on the findings, bioplastics made from PVA and the tannin A. mangium have the potential to be used to create packaging that is UV and active antioxidant resistant. It can be applied as the second (inner) layer of the primary packaging to protect food freshness and nutrition due to their antioxidant activity. [ABSTRACT FROM AUTHOR]