Extraction and Thermogravimetric Characterization of Lignin Phenolic Polymers from Date Seeds by Mild Alkaline Solutions

Date seeds are abundant lignocellulosic waste materials contain lignin phenolic polymers that act as antioxidants in food, cosmetic and pharmaceutical industries. Lignin have been extracted by several methods including alkaline medium. In the present work, optimum alkaline conditions for extraction of and de-polymerization of lignin from date seeds into low molecular weight phenolic compounds were studied. Date seeds surface were characterized before and after extraction by FTIR and thermal analysis (TGA and DTG).Total phenolic content, TPC and antioxidant capacity of extracts were evaluated spectrophotometrically. Maximum TPC was 124±8.78 µg GAE/mL extract and optimum antioxidant capacity was determined as DPPH free radical inhibition (I= 76.56%). The optimum values of TPC and DPPH inhibition were attained at 0.005- 0.010M Na₂CO₃.

extraction,  antioxidant,  DPPH,  total phenolic,  ,  TGA, date seeds