桂圆壳水不溶性膳食纤维吸附NO_2^-、胆酸钠的研究

STUDY ON THE ADSORPTIVE ABILITY FOR NITRITE BY THE WATER-INSOLUBLE DIETARY FIBRE FROM LONGAN SHELL

采用化学法制备了桂圆壳水不溶性膳食纤维,产率为40.59%,其持水力和溶胀力分别为4.42g/g和3.24mL/g。测定了桂圆壳水不溶性膳食纤维对NO2-、胆酸钠的吸附作用。在酸性条件下桂圆壳水不溶性膳食纤维对NO2-具有明显的吸附作用,随pH的升高其吸附能力明显减弱;当pH=2.0时,最大吸附速率为0.137μmol/(g·min),最小清除浓度为1.55μmol/L,达吸附平衡时间为74.3min。在pH6.0条件下桂圆壳水不溶性膳食纤维对胆酸钠具有较强的吸附作用,其吸附能力随其用量的增大而增强,但到达吸附平衡的时间也相应增加。膳食纤维用量分别为1.0g、2.0g、3.0g、4.0g时,其最终吸附率分别为9.5%、43%、51%和80.5%,达吸附平衡时的时间分别为1.7h、2.6h、3.7h、4.1h。

The water-insoluble dietary fibre were extracted from Longan shell by chemical method. The extraction rate was 40.59 %. Its water holding capacity and expansion capacity were 4.42 g/g,3.24 mL/g, respectively. The adsorptive ability of the water-insoluble dietary fibre for nitrite and bile sodium have been studied also in this paper. Under the condition of pH2.0, the water-insoluble dietary fibre had high adsorptive ability for nitrite. It adsorbed nitrite at a maximum rate of 0.137 μmol/（g ·min） to a minimum concentration, 1.55 μmol/L. And the adsorptive reaction reached equilibrium in 74.3 min. Its adsorptive ability for nitrite decreased sharply as pH increased. Under the condition of pH6.0, the water-insoluble dietary fibre had high adsorptive ability for bile sodium. Both its adsorptive ability and the time of adsorptive equilibrium increased sharply as the mass increased. When the mass of the water-insoluble dietary fibre was 1.0 g, 2.0 g, 3.0 g, 4.0 g, its final adsorptive rate was 9.5 %,43 %,51% and 80.5 %,and the time of adsorptive equilibrium was 1.7 h, 2.6 h, 3.7 h,4.1 h,respectively.