The present invention provides a water-soluble modified gum arabic with a weight average molecular weight not less than 0.9 million and arabinogalactan protein not less than 17% by weight obtained by heating Acacia Senegal gum arabic and modified water-soluble gum arabic with a weight average molecular weight not less than 2.5 million and with protein containing high molecular weight components of not less than 25% by weight. Moreover, the present invention provides modified gum arabic with standardized and predictable molecular properties and methods for providing the modified gum arabic endowed with high emulsification efficiency and stability and for uniforming natural variations in unmodified gum arabic. The present invention changes the natural protein distribution of gum arabic, and increases AGP content.