Oxalic extraction of high methoxyl pectin and its application as a stabiliser

The objective of this work was to extract high methoxyl (HM) pectin with oxalic acid, characterise its physicochemical properties and evaluate its dispersion stability in acidified milk drink (AMD). HPSEC-MALLS analysis revealed that the obtained HM pectin was high in molecular weight (522.4 kDa). The zeta-potential of the obtained HM pectin in aqueous solution at pH 4.0 was -31.5 mV. The AFM images proved that the obtained HM pectin contained several long linear molecules. The apparent diameter of AMD stabilised by the obtained HM pectin was 636 nm at the concentration of 3.0 parts per thousand. The stability analysis of AMD and the microscopic observation with confocal laser scanning microscopy (CLSM) proved that the obtained HM pectin was a prominent stabiliser in AMD.