Abstract: Sugar beet pulp is a main by-product of beet sugar industry． The comprehensive utilization of sugar beet pulp and its secondary pulp is critical to add value to the beet sugar industry． Five alkaline-extracted polysaccha- rides (AEP) were extracted from the remaining pulp of sugar beet pectin (SBP) by using an alkaline extractant (alkali dosage 1 ～4meq/g) at 90℃ for extraction duration of 1h． Effects of alkali dosage on the yield，structure and emulsify properties of AEP were investigated． The results show that，with the increase of alkali dosage，both the galacturonic acid and ferulic acid contents will decrease，whereas both the neutral sugar content and weight- average molar mass will increase． AEP2. 5 (extracted at alkali dosage 2. 5meq/g) has the highest yield (35. 6%) and its protein content is 20. 77%． Emulsifying performance of AEP is influenced by alkali dosage; AEP1. 0 and AEP2. 5 have superior emulsifying activities than the remainder，while AEP2. 0，AEP3. 0，AEP4. 0 and sugar beet pectin have comparable emulsifying activities． AEP fresh emulsion contains higher proportions of small droplets (volume average particle size d 4，3 ＜1μm) than SBP fresh emulsion． AEP2. 5 exhibited better emulsifying activity and stability than SBP as indicated by their different d 4，3 values (0. 847μm for AEP2. 5 versus 0. 958μm for SBP); d 4，3 increase to 0. 911μm and 1. 507μm for AEP2. 5 and SBP respectively after 7 days' storage at 55℃． At critical concentrations of 2. 50% and 1. 25%，AEP2. 5 and SBP，respectively，gave their optimum emulsifying perfor- mances with d 4，3 values of 0. 404μm and 0. 825μm．

Key words: alkaline-extracted polysaccharides, sugar beet pulp, emulsifying activity, emulsifying stability, struc- tural analysis