The effects af pH, heat and added salts on the physicochemical properties of pectin solution were investigated. Heating at 100°C for up to 120min decreased the viscosity of pectin at all pH values from 2 to 8. Its viscosity at pH values between 3 and 7 was higher than at other pH values, irrespective of heating. The molecular size distribution of the pectin heated at various pH values was measured using Sephadex G-200 column chromatography. The peak height of the pectin became lower with increased heating time within a pH range of 2-5, suggesting that heating induced acid-hydrolysis of the pectin in this pH range. Heating at a pH above 7 also decreased the molecular size of the pectin mainly due to transelimination. The decrease in the content of methoxyl groups was a slight on heating over an acidic pH range due to rapid saponification caused by the increased heating time. The viscosity of unheated pectin was highest upon addition of 0.5 M Na⁺ or K⁺. Addition of Ca²⁺ also increased the viscosity, whereas no effect of Mg²⁺ addition was observed.