Synthesis, characterization, and antimicrobial evaluation of polyvinylalcohol-osthol composite films

Although poly-vinyl alcohol (PVA) has certain mechanical drawbacks such as a weak barrier, it has widely been used in food packaging over the last many years. To increase the suitability of PVA (C₂H₄O)_n and render it ideal for food packaging, a diversity of studies have already been carried out. In the below-mentioned script, we, for the first time, report the use of natural product osthol in making a new composite with PVA for enhancing thermal, physicochemical, and antimicrobial properties. The significant aim of the report is the insertion of osthol (C₁₅H₁₆O₃) into PVA polymer, which is to be subsequently used for antimicrobial applications. The synthesis of the polymer composite film is done by solvent casting method and is characterized by SEM, XRD, FT-IR, and UV-Vis spectroscopy analysis. The manifestation of antimicrobial activity against (S. aureus) (ATCC8738P), E. coli (ATCC8739), Aspergillus niger, Alternaria alternata, and Fusarium solani by the film composite is remarkable. The addition of osthol molecule increases the tensile strength of PVA films from 18.73 ± 0.56 Mpa (PVA) to 24.58 ± 0.49 Mpa (15 mL). As a result, tensile strength increases by 23.79% in a film containing a higher concentration of osthol (15 mL). The barrier properties of PVA osthol composite films improve with the incorporation of osthol. OTR and WVTR decrease by 43.03% and 30.24%, respectively, on the addition of 15 mL osthol. Reduction in OTR and WVTR of the films could increase their applicability in the food sector. An increase in contact angle from 43° (pure PVA) to 66.7° increases the hydrophobic character of the composite films which is desirable for food packaging. This noticeable enhancement of the properties of the PVA film like hydrophobicity, mechanical, barrier, and antimicrobial is supporting the potential application of achieved material in packaging of easily perishable foods like fruits and vegetables by extending their shelf life.