Chemical composition and biotechnological properties of a polysaccharide from the peels and antioxidative content from the pulp of Passiflora liguralis fruits

A new polysaccharide with a high molecular weight (greater than 1 X 10(6) Da) was extracted and characterized from the peels of Passiflora liguralis (granadilla) fruits. Chemical composition of the biopolymer, performed by using a high pressure anion exchange-pulsed amperometric detector (HPAE-PAD), showed the presence of six different sugar residues: xylose, glucose, galactose, galactosamine, an unknown component, and fucose in the relative ratio of 1: 0. 5:0.2:0.06:0.05: trace. The optical rotation of this xyloglucan was [(alpha](D)25 degrees C = - 186.42 (concentration of 1.4 mg/mL of H2O), and the viscosity was dependent on the concentration and pH, showing a maximum value of 1.4 eta at a concentration of 3% in distilled water and a maximum value of 7.0 eta in citrate buffer solution. Thermogravi metric analysis indicated that this biopolymer was very stable at high temperatures, showing a degradation temperature at 280 degrees C. The characterization of the polysaccharide was also investigated by spectroscopic methods (H-1 NMR and IR) pointing out the complexity of this biopolymer and the presence of sugar residues in a-manno, (x-gluco-galacto, and beta-gluco-galacto configurations. The formation of a biodegradable film using this novel xyloglucan was reported, and the anticytotoxic activity of the polysaccharide was studied in a brine shrimp bioassay. Considerable antioxidant activity (Trolox equivalent antioxidant capacity (TEAC) value of 0.32,mu M/mg fresh product) was noted in the lipophilic extracts of Passiflora liguralis fruits, indicating, in this fruit, an alternative source of bioactive compounds.