This invention modifies pectin, and improves, by the use of the modified pectin, physical properties of a subject composition, such as dispersion stability, emulsifying activity/emulsion stability, water holding property (syneresis inhibiting property), texture, viscosity development property, and gelling property. Pectin is modified by heating a raw material pectin in the form of a powder at 50 to 150.degree. C. for 1 minute to 48 hours. Preferably, as a raw material pectin to be heated, pectin whose loss upon drying is 20% (w/w) or lower is used. More preferably, the raw material pectin is heated at 50 to 150.degree. C. for 1 minute to 48 hours at a relative humidity of 20 to 90% (w/w) and/or under a reduced pressure.