Lemon juice improves the extractability and quality characteristics of pectin from yellow passion fruit by-product as compared with commercial citric acid extractant.

An environment-friendly procedure, allowing the extraction of safe pectin products with good functional properties from yellow passion fruit by-product, was developed using two natural acid extractants, namely, pure lemon juice and citric acid solvent. The results show that both of them solubilise, from cell wall material, pectins characterised by high galacturonic acid content (64-78% w/w), degree of esterification (52-73), viscosity-average molecular weight (70-95 kDa) and capable of forming gels in the presence of high soluble solids (sucrose) content and acid. However, compared to pure citric acid solvents, lemon natural juice and its concentrate isolate, under similar extraction conditions, pectins of superior quality characteristics, i.e., higher galacturonic acid content, degree of esterification, viscosity-average molecular weight and gelling power.