脱脂羊脑蛋白酶解条件优化及酶解产物体外抗氧化活性

以脱脂羊脑蛋白为原料,采用响应面(response surface method,RSM)法建立脱脂羊脑蛋白的枯草芽孢杆菌中性蛋白酶水解回归模型,优化酶解工艺条件,在体外研究脱脂羊脑中性蛋白酶酶解产物的抗氧化性能。结果表明:脱脂羊脑蛋白底物质量浓度为3.03 g/100 mL,酶添加量为5 653.20 U/g,温度为39.4 ℃时,脱脂羊脑蛋白水解度最高,达到(14.59±1.26)%。当脱脂羊脑蛋白水解度为(14.39±1.17)%时,酶解产物对1,1-二苯基-2-三硝基苯肼(1,1-diphenyl-2-picrylhydrazyl,DPPH)自由基和羟自由基(?OH)清除能力最强;当脱脂羊脑蛋白水解度为(12.48±0.71)%时 ,酶解产物对超氧阴离子自由基(O2-?)清除能力和总还原能力最强;当脱脂羊脑蛋白水解度为(12.48±0.71)%时,酶解产物对DPPH自由基、?OH、O2-?、亚硝酸根阴离子的IC50分别2.49、3.13、10.37、10.89 mg/mL,酶解产物对Fe2+螯合率的IC50为7.48 mg/mL,证明脱脂羊脑蛋白酶解产物具有一定抗氧化活性。

Optimization of Enzymatic Hydrolysis of Goat Brain Protein and Antioxidant Activity of the Resultant Hydrolysates

The enzymatic hydrolysis parameters of defatted goat brain protein with Bacillus subtilis neutral protease were
optimized by response surface methodology. The optimized parameters were determined as follows: substrate concentration,
3.03 g/100 mL; enzyme/substrate ratio, 5 653. 20 U/g; and hydrolysis temperature, 39.4 ℃. The maximum degree of protein
hydrolysis was (14.59±1.26) % with the optimized parameters. The antioxidant activity of the resultant hydrolysates was
investigated in vitro. The antioxidant activity presented its maximum value when the hydrolysis degree was (12.48±0.71)%.
The IC50 of the protein hydrolysates for scavenging 1,1-diphenyl-2-picrylhydrazyl (DPPH), hydroxyl, superoxide anion, and
nitrite radicals were 2.49, 3.13, 10.37 and 10.89 mg/mL, respectively, and the IC50 for chelating Fe2+ ions was 7.48 mg/mL.
These results suggest that the protein hydrolysates possess excellent antioxidant activity.