Effects of metal ions on the physico-chemical, microstructural and digestion characteristics of alkali-induced egg white gel
Effects of metal ions on the physico-chemical, microstructural and digestion characteristics of alkali-induced egg white gel
复制标题
金属离子对碱蛋白凝胶理化、微观结构和消化特性的影响
DOI：
10.1016/j.foodhyd.2020.105956
复制
发表时间：
2020-10-01
影响因子：
10.7
通讯作者：
Tu, Yonggang
中科院分区：
文献类型：
--
作者：
Deng, Chunyang;Shao, Yaoyao;Tu, Yonggang
松花蛋是一种碱性蛋制品，传统上依靠添加某些重金属离子来保证其品质。为解决皮蛋中重金属离子（Cu 2+）可能存在的安全问题，改进腌制工艺，研究了不同浓度（0%~ 0. 133%）的K+、Ca 2+、Zn 2+和Fe 3+对鸡蛋白色蛋白（EW）在强碱条件下凝胶行为和消化特性的影响。结果表明，多价离子对碱诱导EW团聚体的粒径有促进作用。随着K+浓度的增加，碱诱导鸡蛋白色凝胶的可溶性蛋白含量、持水力、硬度和弹性均上级优于Ca 2+、Zn 2+和Fe 3+。添加Ca 2+或Fe 3+后，EWG的浊度增大，显微结构粗糙。EWG形成的主要分子间作用力是离子键和二硫键。傅里叶变换红外光谱（FTIR）分析表明，强碱和金属离子诱导的二级结构相互转换。添加金属离子提高了凝胶的消化率。电泳结果表明，各酶带间差异不显著。主成分分析表明，提取了4个主成分，解释总方差的88%。结果表明，低浓度的多价离子有利于提高凝胶的性能。K+对凝胶性能有显著的增强作用，而Ca 2+、Zn 2+和Fe 3+更有利于聚合物的形成，从而通过形成或破坏分子间力来影响碱诱导EWG的性能。
Preserved egg is an alkaline egg product and traditionally relied on the addition of certain heavy metal ions to ensure its quality. To solve the possible safety problem of the heavy metal ions (Cu2+) in preserved egg and improve the pickling process, the effects of alternative ions (K+, Ca2+, Zn2+ and Fe3+) at various levels (0%-0.133%) on the gelation behavior and digestion characteristics of egg white (EW) proteins under strong alkali treatment were investigated. Results showed that multivalent ions promoted the particle size of alkali-induced EW aggregates. As the concentration of K+ increased, the soluble protein content, water-holding capacity, hardness and springiness of alkali-induced egg white gels (EWGs) were superior to those of Ca2+, Zn2+ and Fe3+. EWGs had larger turbidity and rougher microstructures when Ca2+ or Fe3+ was added. The primary intermolecular forces involved in the formation of EWG were ionic bonds and disulfide bonds. Fourier transform infrared spectroscopy (FTIR) analysis showed that strong alkali and metal ions induced the secondary-level structure to interconvert. Adding metal ions increased the gel digestibility. Electrophoresis results showed no significant difference among various bands of the soluble part of EWGs. Principal component analysis showed that four principal components were extracted, explaining 88% of total variance. It was concluded that low concentration of multivalent ions improved the performance of gels. K+ had a significant enhancement on gel properties, while Ca2+, Zn2+ and Fe3+ were more conducive to the formation of polymers, thereby affecting the properties of alkali-induced EWGs by forming or destroying intermolecular forces.