Abstract

The golden leaf vine (Bauhinia aureifolia K. & S.S. Larsen) is renowned for its distinct heart-shaped leaves and intricate vein patterns, which display natural variations in golden or reddish-brown hues. These unique leaves are traditionally used for decorative purposes and as components of handicraft items. This study aimed to enhance the durability and preserve the natural appearance of these golden-phase leaves with a protective coating. A composite of zinc oxide (ZnO) nanoparticles integrated with chitosan and polyvinyl alcohol (PVA) was formulated and applied by spraying. The results demonstrated that the ZnO-PVA-chitosan composite effectively protected the leaves from moisture and ultraviolet (UV) radiation, significantly minimizing surface degradation and color fading after 18 cycles of accelerated aging. All RGB and CIELAB color indices showed less than five units of deviation from their initial values, indicating strong color retention. The increased L* value reflected a brighter appearance in the spray-coated leaves. In addition to preserving color vibrancy, the composite coating also maintained the structural integrity of the leaves more effectively than the uncoated or differently coated samples. This spray coating of ZnO-PVA-chitosan offers a promising solution for extending the lifespan of golden-phase leaves used in cultural and decorative applications while preserving their natural beauty.