甜菜粕是甜菜糖产业的大宗副产物，合理利用甜菜粕及其二次废粕是提升我国 甜菜制糖产业经济价值的重要途径． 文中以甜菜果胶(SBP)加工剩余的废粕为原料，采用 热碱法(碱用量 1 ～4 meq/g，温度 90 ℃，提取时间 1 h)提取出 5 种碱溶性多糖(AEP)，考 察碱用量对 AEP 的产率、结构及乳化特性的影响． 实验结果表明:随着碱用量的增大， AEP 的半乳糖醛酸及阿魏酸含量逐渐下降，中性糖含量和重均分子量逐渐提高;碱用量 为 2． 5meq/g 提取所得的 AEP2． 5 产率最高(为 35． 6%)，其蛋白含量高达 20． 77%;碱用 量对 AEP 乳化特性的影响显著;AEP1. 0、AEP2． 5 的乳化活性较高，AEP2. 0、AEP3. 0 和 AEP4. 0 次之且与 SBP 相当;AEP 新鲜乳液中小油滴(体积平均粒径 d 4，3 ＜1μm)的比例高 于 SBP 新鲜乳液(p ＜0． 05);AEP2． 5 的乳化活性及稳定性均超过 SBP，由两者制备得到 的新鲜乳液的 d 4，3 分别为 0． 847 和 0． 958 μm，在 55 ℃ 下存放 7 d 后，其 d 4，3 分别增大至 0． 911和 1．507μm;AEP2．5 及 SBP 所制备的乳液达到最小粒径(分别为0．404 和0．825μm) 所需要的临界质量分数分别为 2． 50%、1． 25%．

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．