纤维素酶对米糠可溶性膳食纤维含量及抗氧化性的影响

Effects of cellulase enzyme modification on soluble dietary fibre content and antioxidant activity of rice bran

采用纤维素酶水解米糠膳食纤维,以可溶性膳食纤维含量为指标,通过单因素实验和正交实验对酶解条件进行优化,并对在最优条件下制备的可溶性膳食纤维和不溶性膳食纤维进行分离,对其抗氧化性质作进一步的研究。结果表明,在pH5.0,酶的添加量为65EGU/g米糠膳食纤维的条件下,50℃水解3h,可溶性膳食纤维含量最高,为6.97%;经纤维素酶处理得到的总膳食纤维和可溶性膳食纤维的总酚含量分别达到4.38±0.30、(18.53±1.41)mg没食子酸·g-1,分别是酶解前的2.08倍和8.82倍;总抗氧化能力分别达到15.43±0.62、(35.25±3.18)μmol Trolox当量·g-1,分别是酶解前的2.13倍和4.86倍;纤维素酶处理后得到的膳食纤维清除DPPH·,·OH,O-2·的能力显著增强;在亚油酸体系中的抗氧化能力均强于0.5mg/mL的抗坏血酸;膳食纤维的总抗氧化能力和还原力都与总酚含量间均存在显著的正相关。

Cellulase was used to improve soluble dietary fiber（SDF） content of rice bran dietary fiber（ RBDF）.The enzymatic hydrolysis was optimized through single factor experiments and orthogonal experiments.Total, soluble and insoluble dietary fiber （TDF, SDF, IDF） were separated respectively under the condition to evaluate their antioxidant activities.Under the condition of cellulase addition of 65EGU per gram RBDF, enzyme pH5.0, hydrolysis temperature of 50℃,time of 3h,SDF content was the highest and up to 6.97%.Total phenolics content（TPC） and total antioxidant capacity（TAC） of TDF and SDF were 4.38 ± 0.30, （ 18.53 ± 1.41 ） mg gallic acid and 15.43 ± 0.62, （ 35,25 ±3.18） μmol Trolox per gram dietary fiber respectively.DPPH-, .OH,O2- · scavenging capacity increased significantlyThe three types of dietary fiber can suppress the oxidation of linoleic acid system and the antioxidant activity were higer than the antioxidant activity of 0.5mg/mL Vc.TAC and reducing power were positive related to TPC（p 〈0.01 ）.