高强度超声波浴对小麦醇溶蛋白结构及抗原性的影响

Effects of high-intensity ultrasonic bath on the structure and antigenicity of gliadin

小麦是世界上生产和消费最广泛的粮食作物,同时也是公认的八大过敏性食品之一,而麦醇溶蛋白(Glia)是诱发小麦过敏的主要过敏原之一,为探究小麦蛋白脱敏的新方法,采用高强度水浴超声波(HIWU),设定不同的超声功率(0、240、360、480、600 W)对Glia进行处理。测定了Glia中游离氨基和游离巯基的含量,利用傅里叶变换红外光谱(FTIR)、荧光光谱和拉曼光谱表征Glia的结构,通过免疫印记吸附试验(Western blotting)和间接非竞争性酶联免疫吸附试验(ELISA)测定了Glia与抗体的反应能力。结果表明:高强度超声波浴对Glia的结构和抗原性影响显著;480 W超声处理对Glia的抗原抑制效果最好;超声波浴使Glia的二级和三级结构发生显著变化,其有序结构(α-螺旋、β-折叠)含量减少,无序结构(β-转角、无规则卷曲)含量增加,酪氨酸和色氨酸残基暴露,维持结构稳定的g-g-g型二硫键含量减少。高强度超声波浴改变了Glia的次级结构,其抗原表位被掩藏或破坏,有效地降低了Glia的抗原性。

Wheat is the most widely produced and consumed food in the world,and it is also one of the eight allergenic foods recognized in the world.Gliadin(Glia)is one of the main allergens that induce wheat allergy.This study aimed to explore the effects of high intensity water bath ultrasound(HIWU)on the structure and antigenicity of Glia.Glia was treated with different ultrasonic power.The results of Western blotting showed that there was a strong immune response before and after ultrasound treatment.Non-competitive enzyme-linked immunosorbent assay(ELISA)showed that HIWU significantly reduced the antigenicity of Glia,and the highest immunosuppression rate was 33.03%±1.72%after 480 W HIWU.Furthermore,SDS-PAGE showed that HIWU did not produce small molecular subunits of Glia but cause aggregation of some protein subunits.HIWU reduced the content ofα-helix andβ-sheet of Glia to make it disordered.HIWU caused quenching of the fluorescence of Glia,and the content of free sulfhydryl groups in protein increased.Meanwhile,Raman spectroscopy analysis showed that the main conformation of the disulfide bond changed from g-g-g to g-g-t,tyrosine and tryptophan changed from the original embedded state to the exposed state.HIWU altered the secondary and tertiary structures of Glia,resulting in the deletion or destruction of Glia epitopes,thereby effectively inhibiting the antigenicity of Glia.This study will broaden the application of ultrasonic technology in cereal products and provide a theoretical reference for the production of hypoallergenic wheat food.