Sago Starch Reinforced With Cellulose Microfibers Isolated From <i>Dialium cochinchinense</i> Residue

ABSTRACT This research investigated the development of sago starch (SS) film reinforced with velvet tamarind ( Dialium cochinchinense ) peels for potential biopolymer film applications. SS was gelled at 80°C and plasticized with glycerol. After that, VT and treated VT (TVT) fibers were incorporated with content of 1, 3, and 5 wt%. The SS, SS_VT, and SS_TVT biocomposites were systematically evaluated for their transparency, water resistance and tensile properties. The addition of VT and TVT significantly improved ultraviolet (UV) protection, although this improvement was accompanied by a decrease in visible light transparency. Water absorption and water vapor transmission of the biocomposite films also decreased compared to neat SS. Moreover, the biocomposite films exhibited substantially higher tensile strength (TS) and Young's modulus (YM) than neat SS film. Notably, the composite film containing 3 wt% VT demonstrated the highest TS and YM value. This confirmed the effective dispersion of 3 wt% of VT within starch matrix and strong interface interaction between cellulose fibers and starch, as revealed by FTIR and SEM analysis. The thermal degradation temperatures of biocomposite films containing 1 wt% VT and TVT were shifted to higher values compared to that of the starch matrix. The incorporation of VT and TVT enhanced the tensile properties of the biocomposite films; however, TVT‐reinforced films showed relatively inferior performance compared to VT reinforced films, primarily due to increased particle agglomeration, as observed by SEM. Totally, SS films reinforced with VT show strong potential for biopolymer packaging applications, owing to their improved water resistance and mechanical properties.