Unveiling the Potential of Secang (Caesalpinia sappan L.) as a Novel Tanning Agent: A Promising Alternative for the Leather Industry

Abstract

The exploration of vegetable tanning's natural resources is fascinating as an alternative to basic chromium sulfate for its natural abundance and considerable environmental impact. In this work, an attempt has been made to extract vegetable tannin from Caesalpinia sappan L. bark using water as a solvent with different levels of temperatures and incubation times. The highest yield efficiency was observed at 80 °C for 4 hours. The presence of tannin content and polyphenolic compounds were screened by the phytochemical analysis using Iron (III) chloride (FeCl3), sodium hydroxide (NaOH), and ensured by the thin layer chromatography (TLC), and the Fourier transform infrared (FTIR). The extracts were then determined by percentage of extract yield, phytochemical, tannin type, moisture, total solids, and tannin characteristics. The findings indicate that the extract of Secang contains 4.98±0.28% total moisture, 95.02 ± 0.28% total solids, and 72.12 ± 2.81% total soluble solids, 52.28 ± 1.79% tannins, and 19.84 ± 1.41% non-tannin. Moreover, Fourier transform infrared (FTIR) analysis revealed a clear functional group within Caesalpinia sappan L., as evidenced by the type of tannin that is condensed. The TLC assay exhibited a considerable intensity under UV lights. It included several shades of light blue and blue, which could indicate the presence of secondary metabolites and tannin. Compared to mimosa, as the commercial standard for tanning agents in the leather industry, Caesalpinia sappan L. presents promise as an eco-friendly substitute for basic chromium sulfate and a new alternative source of vegetable tannin for the leather industry.