Effect of various solvent systems on extraction of phenolics, tannins and sugars from beach pea (Lathyrus maritimus L.)

Phenolic compounds and sugars were extracted from beach pea (Lathyrus maritimus L.) seeds using methanol-water, ethanol-water and acetone-water solvent system (80:20, v/v) at 80°C. The extracted solvents were used for determining the content of phenolic compounds and sugars by colorimetrically. UV spectra were measured and TLC analysis was performed on silica gel to compare phenolic compounds extracted in particular solvent systems. UV absorbance of phenolics (280 nm) and condensed tannins were measured at 500 nm after colour development. The vanillin positive acetone extracts were pooled, concentrated and subsequently subjected to HPLC analysis. Both (+)-Catechin and (-)-Epicatechin were identified in the extraction solution. Acetone-water system extracted considerably higher amounts of phenolic compounds and condensed tannins than the ethanol-water or methanol-water systems. UV spectra of pooled extracts were similar for all solvent systems employed, but TLC plate analysis showed that the presence of higher molecular weight tannins which were not found when methanol-water or ethanol-water were used for extraction.