Bu Guanhao, Zhang Nan, Chen Fusheng
College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China.
College of Food Science and Technology, Henan University of Technology, Zhengzhou 450001, China.
Food Res Int. 2015 Oct;76(Pt 3):511-517. doi: 10.1016/j.foodres.2015.08.004. Epub 2015 Aug 6.
Soybean is nutritious and is an excellent source of high-quality protein for human food and animal feed. However, glycinin (11S) is considered as the major allergenic protein that causes soybean allergies. Glycosylation is widely used to remove food protein allergens. In this study, soybean 11S was isolated and used in a glycation reaction with lactose at a weight ratio of 4:1 at 55°C and 79% relative humidity for different periods of time. The effects of glycosylation on the antigenicity and residual allergenicity of 11S were investigated, using the specific IgG polyclonal antibodies for glycinin and soy-allergic patient sera by indirect competitive, enzyme-linked immunosorbent assay (indirect competitive ELISA). Meanwhile, the degree of glycation was determined by the trinitrobenzene sulfonic acid (TNBS) method. The structural properties of 11S-lactose conjugates were characterized by SDS-PAGE, Fourier transform infrared spectrum (FTIR), and ultraviolet spectroscopy. Glycosylation effectively decreased the antigenicity and allergenicity of 11S if we increased the reaction time. The antigenicity of 11S after glycosylation was reduced by approximately 30% compared with raw 11S, while allergenicity of 11S was reduced by 9%. The changes in secondary structures of glycated 11S may have influenced the allergic epitopes of protein. Therefore, we suggest that introducing lactose in 11S is an effective method to remove the antigenicity and allergenicity of glycinin.
大豆营养丰富，是人类食品和动物饲料优质蛋白质的极佳来源。然而，大豆球蛋白（11S）被认为是引发大豆过敏的主要致敏蛋白。糖基化被广泛用于去除食品蛋白过敏原。在本研究中，分离出大豆11S，并在55°C、相对湿度79%的条件下，以4:1的重量比与乳糖进行糖基化反应不同时长。使用针对大豆球蛋白的特异性IgG多克隆抗体和大豆过敏患者血清，通过间接竞争酶联免疫吸附测定法（间接竞争ELISA）研究糖基化对11S抗原性和残余致敏性的影响。同时，采用三硝基苯磺酸（TNBS）法测定糖基化程度。通过SDS-PAGE、傅里叶变换红外光谱（FTIR）和紫外光谱对11S-乳糖缀合物的结构特性进行表征。如果延长反应时间，糖基化可有效降低11S的抗原性和致敏性。糖基化后11S的抗原性与未处理的11S相比降低了约30%，而致敏性降低了9%。糖基化11S二级结构的变化可能影响了蛋白质的过敏表位。因此，我们认为在11S中引入乳糖是去除大豆球蛋白抗原性和致敏性的有效方法。
