By applying a function to stabilize the protein in a pH range around the isoelectric point of the protein in water-soluble polysaccharide, it was an object of the dispersion stabilizer novel and provide an acidic protein food or drink using the same. Was obtained by extraction of soybean seed raw material for water-soluble polysaccharide having an acidic sugar as a constituent sugar, and that is treated with divalent metal ions, treated with phosphoric acid ions in a row, and around the isoelectric point of milk protein It was possible to improve the dispersion stability of the protein particles in the pH range, to obtain the phosphorylated water-soluble polysaccharide. In addition, it was possible to obtain an acidic protein food and beverage of low viscosity using the phosphorylation water-soluble polysaccharide.水溶性多糖類に蛋白質の等電点付近のpH域で蛋白質を安定化する機能を付与することで、新規な分散安定剤およびこれを用いた酸性蛋白飲食品を提供することを課題とした。大豆種子原料の抽出等により得た、構成糖として酸性糖を有する水溶性多糖類に対し、二価金属イオンで処理し、続けてリン酸類イオンで処理することで、乳蛋白質の等電点付近のpH域における蛋白質粒子の分散安定性を向上させる、リン酸化水溶性多糖類を得ることが出来た。また、このリン酸化水溶性多糖類を用いた低粘度の酸性蛋白飲食品を得ることが出来た。
