Comparing Banana Bunch and Stem Syrup Tannins for Leather Processing

Jenn Hoskins
7th June, 2024

Comparing Banana Bunch and Stem Syrup Tannins for Leather Processing

Image Source: Natural Science News, 2024

Key Findings

  • Researchers in Bangladesh found that tannins from banana bunches and stems can be used as eco-friendly tanning agents for leather
  • Leather tanned with banana extracts showed similar strength and softness compared to traditional vegetable tannins
  • This method offers a sustainable alternative to chrome tanning, utilizing agricultural waste and reducing environmental impact
The leather industry has long relied on chrome tanning for its ability to produce high-quality leather with excellent hydrothermal stability, better dyeing characteristics, and softness. However, chrome tanning has been criticized for its severe environmental impact and adverse effects on human health and other organisms[2]. This has led researchers to explore alternative eco-friendly tanning technologies that can produce leather of comparable quality without the associated environmental drawbacks. A recent study conducted by the Bangladesh Council of Scientific and Industrial Research has investigated the use of banana bunch and stem syrup as eco-friendly tanning agents[1]. The study aims to find a sustainable alternative to traditional tanning methods by utilizing vegetable tannins derived from banana waste products. The researchers extracted tannins from banana bunches and stem syrup, achieving an extraction efficiency of 69.80%. The presence of condensed type tanning components was confirmed through FT-IR analysis, which identified various polyphenolic groups in the extracts. The tannin content of the banana bunch and stem syrup was found to be 3.13% and 2.6%, respectively. Additionally, the phenolic content was measured at 1332.37 mg GAE/100g of dried weight for the banana bunch extract and 873.92 mg GAE/100g of dried weight for the syrup. These characteristics make the extracts suitable for use as vegetable tanners. To evaluate the effectiveness of the banana-derived tannins, the researchers applied the extracts to re-tan leather and compared the results with leather tanned using a conventional vegetable tanning agent, quebracho. The tensile strength, tear strength, and elongation percentage for the banana bunch extract were 23.84 N/mm², 68.26 N/mm, and 47.07%, respectively. For the banana stem syrup, these values were 22.97 N/mm², 68.38 N/mm, and 40.70%. The softness of the leather was measured at 1.41 for the banana bunch extract and 2.01 for the syrup. Further testing of the leather samples revealed that the grain crack load, distension at grain crack, strength at ball burst, and distension at ball burst were 246.86 N, 13.24 mm, 530.77 N, and 24.54 mm for the banana stem syrup, and 338.77 N, 13.42 mm, 460.65 N, and 29.08 mm for the banana bunch extract. The shrinkage temperatures recorded for the banana bunch extract, syrup, and quebracho-tanned leather samples were 76.5°C, 75°C, and 84°C, respectively. The flexing endurance of the leather tanned with banana extracts showed acceptable values, all less than 4. The results of the study indicate that leather tanned with banana bunch and stem syrup extracts exhibits satisfactory performance compared to the control trial using quebracho tannins. The banana bunch extract, in particular, demonstrated greater thermal stability, while the syrup showed similar thermal stability to the quebracho-tanned leather. This study builds on previous research that has explored various eco-friendly tanning methods, including the recycling of spent liquors, enhancement of chromium exhaustion, and total replacement of chromium salts[2]. Among these methods, combination tanning—blending two tanning agents to achieve desired leather properties—has shown promise as an alternative to chrome tanning. For instance, blending vegetable tannins with aluminum sulfate has been suggested as a potential chrome-free tanning technology[2]. The use of banana-derived tannins represents a novel approach to eco-friendly tanning, offering a sustainable solution that utilizes agricultural waste products. The findings of this study suggest that banana bunch and stem syrup extracts can serve as effective tanning agents, producing leather with properties comparable to those achieved with traditional vegetable tannins. In conclusion, the research conducted by the Bangladesh Council of Scientific and Industrial Research demonstrates the potential of banana-derived tannins as a viable alternative to conventional tanning agents. This eco-friendly approach not only addresses environmental concerns associated with chrome tanning but also adds value to agricultural waste, contributing to a more sustainable leather industry. Further studies are recommended to optimize the use of banana tannins for industrial applications and to explore the full potential of this innovative tanning technology.

AgricultureBiochemPlant Science


Main Study

1) Comparative evaluation of tannin from banana bunch and stem syrup for leather processing.

Published 15th June, 2024 (future Journal edition)

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2) Alternative tanning technologies and their suitability in curbing environmental pollution from the leather industry: A comprehensive review.

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