为改善甜菜果胶颜色深、色泽暗的问题，文中采用透析、乙醇洗涤( 醇洗) 、H₂O₂ 脱色方法对甜菜果胶进行脱色，并评价脱色工艺与脱色效果、甜菜果胶的分子结构、乳化特性的相关性．研究结果表明，透析法( 截留分子质量为 3000 ～14000 u) 和醇洗( 乙醇体 积分数为 60% ～80%) 两种脱色方法无法降低甜菜果胶的色值，而H₂O₂法则能显著降低 甜菜果胶的色值．考察了H₂O₂ 用量、脱色时间对脱色效果的影响，发现甜菜果胶在 3% 的H₂O₂的碱性溶液中，室温脱色 0．5h 后，色差从 1．71 下降至－0．11，起初暗黄色的甜菜果 胶溶液变为澄清透亮的溶液．此外，甜菜果胶的结构在H₂O₂脱色作用下也发生变化，其半乳糖醛酸、中性糖、阿魏酸等含量降低，分子质量减小，且甜菜果胶的乳化活性下降到 66．7% ～75．0%． 综上所述，H₂O₂对甜菜果胶的脱色效果显著，这可能与H₂O₂破坏了甜菜果胶内源性呈色物质有关．然而，当H₂O₂的氧化效果过强时，甜菜果胶容易发生降解．

In order to solve the dark color problem of sugar beet pectin (SBP),the methods of dialysis，alcohol leaching and H₂O₂decolorization were used to decolor the SBP solution,and the influence of the decoloring proce- dures on the decoloration effect as well as on the molecular structure and emulsifying property of the SBP was evalu- ated.It is found that neither the dialysis (MWCO is 3000 ～14000u) nor the alcohol leaching (the ethanol concen- tration is from 60% to 80%) has any influence on the color value of the SBP,while H₂O₂ can significantly reduce the SBP color value.Therefore，the influence of the H₂O₂ concentration and the bleaching time on the decoloriza- tion efficiency was investigated.The results show that，in an alkaline solution with 3% of H₂O₂ and after the bleaching at the room temperature for 0. 5h,the color value of the SBP decreases from 1. 71 to －0. 11,and the o- riginal dark yellow SBP solution turns into clear and bright solution.Furthermore,the H₂O₂ oxidation decolorization also changes the structure of the SBP,specifically，the contents of D-galacturonic acid,neutral sugar and ferulic acid in the SBP as well as the molecular mass of the SBP decrease,and the emulsifying activity of the SBP decrea- ses to 66. 7% ～75. 0% of the original.It is thus concluded that the decolorization effect of H₂O₂ on the SBP is sig- nificant,which can be attributed to the fact that the endogenous chromogenic material in the SBP is oxidized by H₂O₂ .However,the SBP is likely to be degraded when the oxidation of H₂O₂ is too strong.