Treatment of Paper with Persian Gum (<i>Zedu</i>) in Combination with <i>Satureja khuzestanica</i> Extract: Increasing Mechanical Strength and Fungicidal Effects

Abstract This study proposes a combined treatment based on Persian gum known as zedu that aims to combat some of the main factors contributing to the deterioration of paper-based cultural heritage. Persian gum was used as a reinforcing agent to restore the mechanical strength and stability of paper. The research is a practical study with an analytic-comparative approach testing mechanical strength, resistance to biological attack, and color changes according to standard protocols. Nanoparticles of zedu with varying weight percentages were extracted and combined with calcium hydroxide and glycerol to enhance pH and flexibility. The extract of Satureja khuzestanica was tested for its effectiveness against biological degradation. A treatment solution was applied to paper samples, which were subjected to artificial aging under humidity and temperature conditions following ISIRI-4706 for six full days, and light exposure for 4 days. Measurements revealed an increase in tensile strength depending on the amount of the gum used. Colorimetric measurements indicated minimal color changes for the treated and untreated samples before and after aging. Furthermore, the study demonstrated the inhibition of common fungal growth on treated paper at concentrations of 500 and 100 µl of S. khuzestanica extract.