EXTRACTION, PURIFICATION, CHARACTERIZATION OF DYE FROM COCOA TREE BARK (Theobroma cacao) AND CORN SILK (Maydis stigma) AND THEIR INDUSTRIAL APPLICATIONS

Abstract

The growing niche market for sustainable products is prompting the reintroduction of natural dye on a commercial scale thus making the quest for the extraction of dyes from natural origin a thing of prime importance due to the environmental pollution caused by the various classes of synthetic dyes to the immediate environment. In this study, natural dyes were extracted from cocoa tree bark (Theobroma cacao) and corn silk (Maydis stigma) using aqueous extraction. The physicochemical analysis revealed a pH of 7.84 and 7.33, relative density of 1.02 and 0.90, melting point of 280-287 o C and 292-300 o C and a percentage yield of 68.5 and 16.6 for the extracts respectively. The phytochemical constituents of the dye extract was investigated and it showed considerable reaction to alkaloid, tannins, phenols and saponins but in varying degree. The FT-IR spectra of the dye extracts revealed absorption in the region of 3231cm-1 and 3235 cm-1 confirming the presence of OH stretch of phenolic compounds. Both extracts also revealed bands in the C-C aromatic region with corn silk absorbing in the 1285cm-1 to confirm O-H alcoholic moiety. The XRD revealed both extracts to be amorphous in nature. On application cocoa tree bark extract shows excellent fastness to cotton and batik fabrics. The antimicrobial activities of the dye extract inhibited against all tested pathogens of Escherichia coli, Staphylococcus aureus, Salmonella typhi, Bacillus syphilis, Aspergillus species and Candida species. The study revealed that cocoa tree bark and corn silk are viable alternatives to synthetic dyes.