Isolation, Structural Characterization, and Valorization of Pectic Substances from Algerian Argan Tree Leaves (Argania spinosa (L.)‎ Skeels)‎

الملخص EN

Pectic polysaccharides were solubilized from Algerian argan tree leaves by sequential extraction with water at 100°C (water-soluble pectin; AL-WSP) and EDTA solution at 80°C (chelating-soluble pectin; AL-CSP).

Both AL-WSP and AL-CSP were rich in arabinose (28% and 74.5%, resp.) and had a high content of uronic acid (38.5% and 21.5%, resp.).

Pectic substances were deesterified and fractionated by anion exchange chromatography, giving five fractions for each extract.

Most of the fractions were characterized by methylation analysis and then analyzed by 13C nuclear magnetic resonance spectroscopy.

The results showed that AL-WSP consisted of rhamnogalacturonan type I, with arabinan and galactan branching at the O-4 position of the main rhamnose chain, while AL-CSP consisted of rhamnogalacturonan type I and a block of homogalacturonan.

Antioxidant activities of AL-WSP and AL-CSP were evaluated by electronic spin resonance.

The results showed that the antioxidant potential of AL-WSP (8.1%) and AL-CSP (−1.2%) was significantly lower than that of vitamin E.