Abstract

Since the early 1900s, the Society of Leather Technologists and Chemists (SLTC) has used the hide powder method to evaluate tannin content and quality traits in wattle bark and Mimosa products. This approach has become the global standard in both the wattle bark and leather industries. Alternative methods, such as the Stiasny method, are predominantly employed for estimating adhesive tannin content, and ultraviolet (UV) spectroscopy is applied in both adhesive and tanning processes. However, Near-Infrared Reflectance Spectroscopy (NIRS) has emerged as a highly efficient, cost-effective, and non-destructive analytical tool. NIRS is widely used across various industries, including food and agriculture, and has proven its effectiveness for tannin analysis. This study explored the application of NIRS using different sample preparations, such as milled freeze-dried bark and bark extract solutions. By integrating NIR scans with traditional SLTC methods and elemental analysis, models were developed to predict key properties of wattle bark and its extracts. UV spectroscopy was also tested for tannin determination but showed limited accuracy compared to NIRS. Notably, the NIRS analysis of milled freeze-dried bark demonstrated strong predictive performance for all critical quality parameters. These findings underscore the potential of NIRS as a viable alternative to traditional wattle bark analysis techniques. Its accuracy, speed, and non-destructive nature make it a promising replacement for existing methodologies, offering enhanced efficiency for tannin content and quality analysis in the industry.