真空减压加速皮蛋蛋清凝胶形成的机理

真空减压法可显著缩短皮蛋加工周期,但此技术下皮蛋蛋清凝胶形成的机理还未知。因此,本文研究真空减压法下腌制皮蛋蛋清形成凝胶过程中,蛋清水分迁移、蛋白质构象变化、微观结构及分子间作用力变化等,以探究其凝胶形成机理。结果表明:在皮蛋腌制过程中,蛋清蛋白的疏水性先增加后降低,适宜的疏水相互作用有利于维持蛋白质凝胶结构的稳定;蛋清蛋白的浊度显著增大而溶解性显著降低,Zeta电位增大了1.13倍,静电斥力的增强有利于有序线性蛋白质聚集体的形成,形成了透明的凝胶;α-螺旋结构的相对含量减少至13.00%,而β-折叠和β-转角分别增加至54.00%和20.40%,蛋白质的α-螺旋结构转化为β-结构来参与蛋白质分子之间的聚集;维持蛋白质凝胶的分子间作用力从强到弱依次是是离子键、二硫键、疏水相互作用和相对较少的氢键;通过以上的相互作用,皮蛋蛋清最终形成了规则的包埋着大量结合水的三维纤维网络凝胶结构。

Mechanism of Accelerating the Formation of Preserved Egg White Gel by Vacuum Decompression

The vacuum decompression method can significantly shorten the processing period of preserved eggs,but the mechanism of gelatin formation of egg white gel under this technology is unknown.Thus,in this paper,to explore the gel formation mechanism,water migration in egg white,protein conformational change,microstructure and intermolecular force changes were investigated,during the gelatinization process of egg white of preserved egg using the vacuum decompression method.Results showed that,during the pickling process of preserved egg,the hydrophobicity of egg white protein first increased and then decreased,the proper hydrophobic interaction was helpful to maintain the stability of the protein gel structure.The turbidity of egg white protein was significantly increased while the solubility was significantly reduced,the Zeta potential was increased by 1.13 times,the increase in electrostatic repulsion was beneficial to the formation of ordered linear protein aggregates,forming a transparent gel;the relative content ofα-helical was reduced to 13.00%,while theβ-sheet andβ-turn structure were increased to 54.00%and 20.40%,respectively,theα-helix structure is transformed intoβ-structures to participate in the aggregation between protein molecules;the intermolecular forces that maintain protein gels in order from strong to weak were ionic bonds,disulfide bonds,hydrophobic interactions,and relatively few hydrogen bonding;through the above interactions,preserved egg whites finally formed a regular three-dimensional fiber network gel structure embedded with a large amount of bound water.