The Effect of the Concentration of Pineapple Peel-Based ZnO/Zein Nanocomposite on the Antibacterial Activity of Staphylococcus Aureus and Streptococcus Mutans

ZnO nanoparticles are known to have good antibacterial properties. However, because the particles are prone to agglomeration, their effectiveness can decrease, particularly when they are used as an active ingredient in mouthwash. To address this issue, ZnO nanoparticles were synthesized via green synthesis using pineapple peel (Ananas comosus L.) extract and subsequently combined with Zein polymer through a mixing method to form a nanocomposite, thereby minimizing agglomeration. The concentration of ZnO/Zein nanocomposite affects its ability to inhibit bacterial growth, especially on S. aureus and S. mutans. The results obtained showed that the ZnO/Zein nanocomposite composition of 1:2 at a concentration of 2.5% was the most effective in inhibiting S. aureus bacteria with an inhibition zone of 9.4±0.26 mm. For S. mutans, nanocomposites with a composition of 1:2 and 1:3 at a concentration range of 0.5-2.5% exhibited a relatively stable inhibition ability, ranging from 5.53 to 7.20 mm, which was better than that of pure ZnO. Although the antibacterial activity of the nanocomposite was lower than that of mouthwash containing 0.2% chlorhexidine, it still showed potential as a bacterial inhibitor. It is hoped that this ZnO/Zein nanocomposite can be used as an additive in antibacterial mouthwash formulations.