采用红外及X-衍射等分析手段表征魔芋葡甘聚糖（KGM）与脱乙酰魔芋葡甘聚糖（Da-KGM）结构并比较其持水性和粘度，以纤维素为对照，采用体外模拟人体胃及肠道的pH环境，对比分析KGM及Da-KGM对脂肪及胆固醇的吸附能力。结果显示KGM脱乙酰基后1733 cm-1处的乙酰基的特征吸收峰消失，结晶度增加，持水性下降83.7%，高粘度特性丧失；相比纤维素，KGM具有良好的脂肪及胆固醇吸附能力，其吸附总量随样品质量、吸附时间和胆固醇浓度的增加而增大，与天然KGM相比，Da-KGM的脂肪及胆固醇吸附能力降低，可能是因为KGM脱除乙酰基后KGM分子链间氢键作用加强致使与脂类结合位点减少，以及高粘度特性消失致使对脂类的直接包裹能力下降，提示KGM经脱乙酰加工成魔芋食品后在肠道与脂类的结合能力下降，其减肥降脂的生理功效可能受到影响。

The structures of konjac glucomannan (KGM) and deacetylated konjac glucomannan (Da-KGM) were analyzed using Fourier transform-infrared spectroscopy (FT-IR) and X-ray diffraction analysis, and the water-holding capacity and viscosity of KGM and Da-KGM were compared. With cellulose as a control, an in vitro simulation of the human gastrointestinal tract was prepared, and the fat- and cholesterol-adsorption capacities of KGM and Da-KGM were compared. The results showed that, after deacetylation, the characteristic absorption peak of the acetyl group at 1733 cm-1 of KGM disappeared, the degree of crystallinity increased, the water holding capacity decreased by 83.7%, and the characteristic high viscosity was lost. Compared with cellulose, KGM had a higher capacity to adsorb fat and cholesterol, and the total adsorption capacity increased with increasing sample mass, adsorption time, and cholesterol concentration. Compared with natural KGM, Da-KGM exhibited a decreased capacity to adsorb fat and cholesterol. This might be due to the strengthening of hydrogen bonds between KGM molecular chains, leading to a reduction in the number of binding sites between KGM and lipids and the disappearance of the characteristic high viscosity, causing a decrease in the capacity of KGM to directly bind with lipids. These results indicated that the lipid-binding capacity of KGM in the intestinal tract was reduced after deacetylation, and that its physiological function (weight loss effect) might be affected.