The effect of deep eutectic solvent of DL-menthol and linoleic acid to the properties of pectin-starch biofilm / Nur Ilyana Ismail

Pectin-starch biofilms offer a sustainable alternative for various applications, including food packaging, but often suffer from poor mechanical properties and moisture susceptibility. This study explores the effect of deep eutectic solvents (DESs) composed of DL-menthol and linoleic acid on these biofilms. By incorporating varying concentrations of DES at 5%,6% and 7%, the changes in mechanical performance, water solubility, moisture content, and opacity were investigated. Thus, the FTIR (Fourier-transform infrared) analysis to assess chemical interactions also were conducted. Result indicated that the biofilm with 5%, 6% and 7% DES concentration exhibited higher water solubility (73.58%, 73.68 % and 75.40%) and moisture content (10.40%, 13.24%, 21.24%), leading to increased opacity. Additionally, the biofilms with 5% DES were selected for mechanical property testing with control biofilm due to its properties that has lower moisture content, water solubility and its apparency that less brittle than biofilm with 6% and 7% DES. Biofilm with 5% DES had lower tensile strength (13 MPa) compared to those without DES (14 MPa), suggesting reduced mechanical robustness and increasing the flexibility of biofilm. While DES enhanced the cohesion of the biofilms, they also introduced challenges such as higher susceptibility to moisture and decreased mechanical performance. These findings suggest that while DESs impact certain properties of pectin-starch biofilms, further optimization is needed to balance mechanical strength with other desirable qualities for practical applications.