Optimization of capsaicin purification from Capsicum frutescens Linn. with column chromatography using Taguchi design

Capsaicin is a major capsaicinoids presented in hot chilies and peppers. It is widely used in pharmacology and clinical applications because of its properties such as anti-mutagen, anti-tumor and antioxidant. Therefore, the optimum capsaicinoids extraction was studied. Two different techniques, comparing with traditional soxhlet method, microwave-assisted extraction (MAE) and ultrasonic-assisted extraction (UAE), were used to extract the capsaicinoids from dried chilies (Capsicum frutescens Linn.). The electrical power (90–600 W) and the extraction time (5–20 min) were investigated for MAE while those of 5–30 min were examined for UAE. The optimum method for capsaicinoids extraction was UAE which gave the highest amount of capsaicinoids at 4.01 mg/g of dried chili. Consequently, the Taguchi's experiment design methodology was performed in order to identify the optimum capsaicin separation condition in column chromatography. Three factors including mobile phase ratio (ethanol:water), bed height and flow rate of mobile phase were analyzed. The mixed-level orthogonal array design, L16 (21 × 42) matrix was employed to access the capsaicin purity. The optimum conditions were 40% of ethanol as mobile phase, 25 cm of bed height with the flow rate of mobile phase of 2.5 ml/min. It was also found that the mobile phase ratio was the most important factor in capsaicin separation.

► UAE was the optimum method for capsaicinoids extraction with its content at 4.01 mg/g dried chili.
► By Taguchi's experimental design, three factors impacted the capsaicin purification were mobile phase ratio, bed height, and flow rate.
► The mobile phase ratio was the most important factor in capsaicin separation.