Abstract: The present invention provides a process for producing ?-(3-(1,3/1,6)-D-glucan from a cellular source comprising the steps of alkali extraction of the cellular source; water extraction; acid extraction; and water extraction, where at least one step of water extraction includes pasteurization by steam injection to a temperature of about 100° C. for 15 to about 30 minutes. The solid component produced comprises at least ?-70% 1 (1,3/1,6)-D-glucan by dry weight. The present invention also provides a process of producing mannan and manno-protein complexes comprising the steps of collecting a liquid phase obtained in one an alkali extraction step of the ?(3-(1,3/1,6)-D-glucan process; adjusting the pH of the liquid phase to about 5.0-8.0 with an acid; pasteurizing the liquid phase by steam injection to a temperature of about 100° C. for 15 to about 30 minutes; and isolating the mannans and manno-proteins complexes from the pasteurized liquid phase.