Effect of Extraction Time and Solid-Liquid Ratio on Tannin Extraction from Guava (Psidium guajava) Leaves

Abstract

The study aimed to examine the effect of extraction time and sold-liquid ratio on the tannin contents of Psidium guajava leaves. The leaves were extracted using ethanol as a solvent, and solid-liquid ratios were 1/20, 1/40, and 1/60 (w/v). Extraction was carried out by continuous solid-liquid extraction at 80 °C and the extraction time were 30, 45, 60, 75, and 90 minutes. The highest tannin content was obtained 17.058±0.686 % for dry leaves at 60 minutes and 1/20 (w/v) solid to liquid ratio. It is slightly higher compared to the fresh leaves in similar operating conditions obtained at 12.080±0.589 %. The mass transfer modeling by analytical method resulted in 0.823 as the highest R2 obtained at 1/60 (w/v) for the fresh leave sample. The R2 obtained at fresh leaves indicated that 82.30 % of tannin mass transfer was influenced by extraction time. The value of R2 from the analytical calculation is similar to the value obtained graphically. This study demonstrated that increasing extraction time enhanced the tannin mass transfer until the equilibrium stage has reached.