Extraction of phenolic compounds from bamboo peels using Soxhlet extraction technique

This study aimed to extract phenolic compounds from bamboo peels utilizing the Soxhlet extraction method and optimize the extraction parameters for various ethanol concentrations to maximize the phenolic compound yield. Ethanol-water mixtures of 50%, 60%, and 70% were employed as solvents, with extraction durations of 2 hours and 4 hours. Among them, sample BE-70B (70% ethanol-water mixture with 4 hours of extraction time) stood out as the most exceptional, consistently outperforming other solvent concentrations in various tests. Phytochemical tests were conducted to investigate the presence of flavonoids and tannins in bamboo peels. UV-Vis spectroscopy was utilized to determine the concentrations of total phenolic and tannin compounds in the extracts. The Folin-Ciocalteu reagent and sodium carbonate were used as standards for quantification. Results revealed that the 4 hour extraction with a 70% solvent concentration yielded the highest concentrations of total phenolic and tannin compounds in bamboo peels, measuring 56.39 mg/mL and 56.92 mg/mL, respectively. Furthermore, the antioxidant activity of the bamboo peel samples was determined through DPPH assay, demonstrating their potential as antioxidants. BE-70B solvent exhibited a DPPH EC50 value of around 2.66 mg/mL, signifying that a concentration of approximately 2.66 mg/mL was necessary to achieve a 50% reduction in the initial DPPH radical concentration. This underscored the robust antioxidant capacity of BE-70B. In FTIR analysis, the results of the 70% concentration ethanol solvent extract of bamboo peels showed that the number of adsorption peaks was greater than that of the 50% and 60% concentration ethanol solvent extracts. This research signifies the potential of bamboo peels as a rich source of phenolic compounds with notable antioxidant properties, providing insights into their extraction and potential applications in various industries.