Examination of the Causes of Instability of Soy Protein Isolate During Storage Through Probing of the Heat-Induced Aggregation
Examination of the Causes of Instability of Soy Protein Isolate During Storage Through Probing of the Heat-Induced Aggregation
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通过热诱导聚集研究大豆分离蛋白在储存过程中不稳定的原因
DOI：
10.1007/s11746-015-2684-6
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发表时间：
2015-08-01
影响因子：
2
通讯作者：
Chen, Jie
中科院分区：
文献类型：
--
作者：
Guo, Feng-Xian;Xiong, Youling L.;Chen, Jie
研究了大豆分离蛋白（SPI）制备过程中热团聚对SPI不稳定性的影响。通过在喷雾干燥之前在80或90 °C下加热天然SPI（5%w/v）不同时间来制备具有不同聚集度但相似蛋白质溶解度的样品。然后将样品在37 °C下储存长达12周，并通过原子力显微镜、凝胶渗透色谱法和SDS-PAGE定期分析。在储存的前8周内，所有SPI样品的蛋白质溶解度均显著降低。溶解度损失的速率与初始样品中所含的可溶性聚集体的量和/或尺寸（时间零）呈正相关，表明它们的成核和活化效应。在SDS-尿素溶液中的溶解度测试和二硫化物分析表明，非共价相互作用是蛋白质储存不稳定性的主要驱动力。相反，二硫键和蛋白质羰基丰富的可溶性聚集体，其含量在存储过程中显着增加。这种效应表明共价键作为疏水聚集的阻断剂。
This study investigated the mechanism of instability of soy protein isolate (SPI) as influenced by thermal aggregation during SPI preparation. Samples with different degrees of aggregation but similar protein solubility were prepared by heating native SPI (5 % w/v) at 80 or 90 °C for different times before spray-drying. The samples were then stored at 37 °C for up to 12 weeks and analyzed periodically by atomic force microscopy, gel permeation chromatography, and SDS–PAGE. All SPI samples underwent remarkable protein solubility decreases during the first 8 weeks of storage. The rates of solubility loss were positively correlated with the amounts and/or sizes of soluble aggregates contained in the initial samples (time zero), suggesting their nucleation and activation effects. Solubility tests in SDS–urea solutions and disulfide analysis indicated that non-covalent interactions were the main driving forces for protein storage instability. Conversely, disulfide bonds and protein carbonyls were abundant in soluble aggregates, and their content increased markedly during storage. This effect suggested that covalent linkages acted as blockers for hydrophobic aggregation.