Study on the Physicochemical Properties and Lipid Adsorption Capacity of Deacetylated Konjac Glucomannan

FENG Guan-ping; LI Mei-ying; LIN Hong-yi; SUN Yuan-ming

doi:10.13982/j.mfst.1673-9078.2017.2.006

Abstract：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.