Mix dry ingredients and add, with fat, to water, Heat, while stirring, to 75'C (167'F). Homogenize at 70 kg/cm^2 (1000 psi). Cool down to 5'C (41'F). Add and mix in flavor and citric acid. Pass through continuous freezer, adjusting outlet temperature to-6'C (21'F). Store at -30 to -20'C (-22 to -4'F).