木聚糖酶制取米糠膳食纤维的功能性质

Study on xylanase enzyme modified the rice bran dietary fibre and its functional properties

采用木聚糖酶水解米糠膳食纤维,将制备的可溶性膳食纤维(X-SDF)、不溶性膳食纤维(X-IDF)和总膳食纤维(X-TDF)进行分离,研究其功能性质发现,木聚糖酶酶解后,膳食纤维的持水力持油力显著增强,溶胀性降低;阳离子交换能力未见显著变化;X-TDF、X-IDF和X-SDF对葡萄糖的吸附能力分别是RBDF的1.28倍、1.35倍和2.11倍,X-TDF、X-SDF的葡萄糖透析延迟指数相比RBDF显著升高,X-IDF相比RBDF有所降低;在模拟胃和小肠的环境下,X-TDF、X-SDF对胆固醇的吸附量分别为(19.99±1.26)、(23.26±0.52)mg/g和(22.64±1.48)、(27.06±2.22)mg/g,相比RBDF有显著提高。扫描电镜观察其超微结构发现,膳食纤维由不规则块状颗粒组成,木聚糖酶作用后的膳食纤维结构疏松,出现较多空腔和裂缝。

With rice bran dietary fiber as raw materials, soluble dietary fiber was prepared through xylanase en- zymatic modification to improve the quality of dietary fiber. Total dietary fiber, soluble and insoluble dietary fiber were obtained under optimal condition. Water holding capacity and oil holding capacity were significantly increased, while swelling capacity decreased after xylanase modification. Glucose adsorption capacity （GAC） of total dietary fi- bre （X-TDF）, soluble dietary fibre（X-SDF） and X-IDF were 1.28,1.35 and 2. 11 times of that of rice bran dietary fibre （RBDF）. Glucose dialysis retardation index （GDRI） of X-TDF and X-IDF were significantly enhanced, GDRI of insoluble dietary fibre （X-IDF） was reduced, however. Adsorption capacities of X-TDF and X-SDF for cholesterol were also increased. With observation of the ultrastructure using scanning electron microscopy （SEM） , it was found that many cavities and cracks appeared after xylanase enzyme modification.