Structure characteristics of an acidic polysaccharide purified from banana (Musa nana Lour.) pulp and its enzymatic degradation.

Banana is one of the most important fruits over the world. The chemical composition is critical for the organoleptic properties and health benefits. As one of the leading bioactive components in banana pulp, the polysaccharides may contribute to the beneficial health effects. However, their precise structure information remains unknown. A leading acidic polysaccharide (ABPP) of banana pulp was purified and identified by nuclear magnetic resonnance spectroscopy (NMR) and gas chromatography-mass spectrometry (GC-MS). →4-α-d-GalpA-1→ and →4-α-d-GalpAMe-1→ constituted the backbone. No branch chains were detected. The molecular weight was determined to be 8.9kDa by gel permeation chromatography, which was smaller than previously reported fruit-derived polygalacturonic acids. The precise structure was identified as below. Digestion by enzyme would lead to production of oligogalacturonic acids and quick accumulation of 5000-7000Da fraction.