SUHANI SUHAS KHALANE AND KISHORI SWAPNIL TARFE
Abstract
The global printing industry relies heavily on petroleum-based synthetic inks, which release volatile organic compounds (VOCs) and pose serious risks to environmental and human health. This study investigates the extraction of natural pigments from Terminalia catappa (Indian almond) leaves and their formulation into an eco-friendly, water-based ink suitable for primary and secondary packaging applications. Pigments were extracted from green, yellow, and red leaves via an aqueous maceration method over four to eight days. The extracts were concentrated using a boiling water bath and subsequently formulated into ink using cornstarch as a natural binder and xanthan gum as a viscosity enhancer in a 3:1:1 pigment-to-binder-to-solvent ratio. Pigment identity was confirmed by thin-layer chromatography (TLC), revealing chlorophyll a (Rf = 0.6334), xanthophylls (Rf = 0.4727), and anthocyanins (Rf = 0.7667), all consistent with published reference values. The ferric chloride (FeCl3) test confirmed the presence of phenolic compounds, evidenced by a dark purple complex formation. pH analysis recorded values of 6, 7, and 4 for green, yellow, and red extracts, respectively, reflecting the characteristic stability profiles of their respective pigment classes. The formulated ink demonstrated satisfactory adhesion and drying behaviour on both filter paper and drawing paper substrates. These findings establish T. catappa as a viable source of natural pigments for sustainable, biodegradable ink production, aligning with green chemistry principles and circular economy goals.