Galacturonic acid in pectic substances of sunflower head residues: quantitative determination by HPLC

Abstract Assuming the interest in low-methoxyl pectin from sunflower head residues lies mainly in the production of low-caloric foods a precise and fast method for the quantification of galacturonic acid would be helpful. An HPLC method involving enzymatic hydrolysis was compared with colorimetric and titrimetric procedures. The results showed that the quantitative data obtained by HPLC method (96.5%) were in good agreement with those from other methods (97.0 and 92.9%, respectively). Because the colorimetric analysis is expensive and highly time consuming and titrimetric procedure demands an accurate purification of the pectin, the HPLC method applied in this study proved to be useful for the galacturonic acid quantification.