超声预处理对β-伴大豆球蛋白酶解物抗氧化性的影响

Effects of Ultrasound Pretreatment on Antioxidant Activity of β-conglycinin Hydrolysates

研究比较超声预处理前后β-伴大豆球蛋白的结构,表面疏水性和β-伴大豆球蛋白酶解物抗氧化活性的变化。超声预处理显著提高了β-伴大豆球蛋白酶解物的抗氧化活性(p<0.05),当β-伴大豆球蛋白经过超声功率100 W,超声时间30 min,超声温度50℃处理后,结构变化最显著且其酶解物抗氧化活性最高。β-伴大豆球蛋白经过超声预处理后,在280 nm附近的紫外吸收峰增强,α-螺旋结构含量最多增加3.14%,β-转角结构含量最多增加1.22%,β-折叠结构含量最多减少4.17%,埋藏在疏水环境中的酪氨酸和色氨酸等疏水基团从分子的内部展露到分子的表面,提高了蛋白质的表面疏水性,这可能是β-伴大豆球蛋白酶解物抗氧化活性提高的主要原因。因此,超声预处理是一种辅助提高β-伴大豆球蛋白酶解物抗氧化能力行之有效的方法。

The effects of ultrasound pretreatment on the structure and surface hydrophobicity of β-conglycininand the antioxidant activity of its hydrolysates were studied. The antioxidant activity of β -conglycininhydrolysates was markedly improved（p〈0.05）,through the ultrasound pretreatment on 100 W at 50 益 for30 min,the protein structure change was the most significant and the highest antioxidant activity was obtained.After ultrasound pretreatment,the ultraviolet absorption value of β-conglycinin was enhanced near 280 nm.The 琢-helix content increased by up to 3.14%, and β-turn proportions increased by up to 1.22%, whereas β-sheet proportion decreased by up to 4.17 %. The tyrosine and tryptophan residues of β -conglycinin in thehydrophobic environment were exposed from molecular interior to molecular surface by ultrasonic pretreatment.Compared with non-ultrasound pretreated β-conglycinin,the surface hydrophobicity of ultrasound pretreatedβ-conglycinin samples was increased. It may be the main cause for its improved antioxidant activity of β -conglycinin hydrolysates. In summary,this research demonstrates that combining ultrasound pretreatment andenzymatic hydrolysis can be an effective way for enhancing the antioxidant activity of β -conglycininhydrolysates.