抄録
The role of proteinaceous materials, especially the fraction bound to polysaccharide (i.e, AGP type fraction), in emulsifying was investigated using sugar beet pectin. Enzymatic modification of the pectin using acid proteinases decreased the total protein content from 1.56 to 0.13 % without altering the content of ferulic acid or the composition of constitutional sugar. The modification also decreased slightly the molecular size of the polysaccharide without marked change in the molecular mass. Emulsifying properties of the pectin with or without the modification were compared by the changes in droplet size and creaming stability of O/W emulsion (pH3.0) containing 15 % middle-chain triglyceride and 1.5% pectin as main constituents. The mean droplet size of the emulsion increased from 0.45 to 4.06μm and its creaming stability decreased after the modification. Mass distribution of the pectin within the emulsion elucidated that the modification apparently decreased the amount of the fraction existing in the oil phase from 5.4 to 2.1 % and that the molar mass of the fraction in the oil phase was approx. 2-4 times as large as that in the aqueous phase. Results from the present study suggested the important role of AGP type fraction to explain the emulsifying mechanism of sugar beet pectin.
