Byproduct from Triphala Extraction as Tannin and Rutin Sources for Production of Gallic Acid, Isoquercetin and Quercetin by Solid-State Fermentation

Abstract

Byproduct from Triphala extraction process (BTP) was studied as a substrate for gallic acid, isoquercetin and quercetin production by Aspergillus niger fermentation in this research. The results showed that BTP was a good source of tannin and rutin. Neverthe­ less, the activity of A. niger on BTP as a sole substrate was very low. Supplementing nitro­ gen sources was found to be a key to enhancing conversion of tannin to gallic acid, and rutin to isoquercetin or isoquercetin and quercetin. BTP with 0.75 % sodium nitrate was sug­ gested to be an optimal supplemented nitrogen source for the production of gallic acid and isoquercetin in this research, which yielded the highest contents of 61.6±2.16 mg g –1DS and 3.27±0.29 mg g –1DS , respectively. In addition, the highest extraction yields of gallic acid, isoquercetin and quercetin were obtained by an ultrasound­assisted extraction using methanol as an extraction solvent as 12.24±2.12 mg g –1DS which was around 0.5 time higher than the one without ultrasound­assisted extraction (8.84±1.12 mg g –1DS ).