The effect of ultrasound on casein micelle integrity
The effect of ultrasound on casein micelle integrity
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DOI：
10.3168/jds.2012-5318
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发表时间：
2012-12-01
影响因子：
3.5
通讯作者：
Ashokkumar, M.
中科院分区：
文献类型：
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作者：
Chandrapala, J.;Martin, G. J. O.;Ashokkumar, M.
以新鲜脱脂牛奶、重组胶束酪蛋白和酪蛋白粉为样品，在20 kHz下进行超声处理，考察超声处理的效果。对于新鲜脱脂牛奶，经过60分钟的超声处理后，剩余脂肪球的平均大小减少了约10 nm；然而，酪蛋白胶束的大小被确定为不变。在超声的最初几分钟内，可溶性乳清蛋白的少量增加和相应的粘度降低也发生了，这可能是由于酪蛋白-乳清蛋白聚集体的破裂。在超声处理60分钟的脱脂牛奶样品中，游离酪蛋白含量没有可测量的变化。声波作用引起的短暂的pH值下降；然而，未观察到可溶性钙浓度的可测量变化。因此，新鲜脱脂牛奶中的酪蛋白胶束在超声作用下是稳定的。重组胶束酪蛋白得到了类似的结果，而随着乳清蛋白含量的增加，粘度变化更大。在不影响酪蛋白胶束天然状态的情况下，超声波的控制应用可以有效地应用于逆转过程诱导的蛋白质聚集。
Samples of fresh skim milk, reconstituted micellar casein, and casein powder were sonicated at 20 kHz to investigate the effect of ultrasonication. For fresh skim milk, the average size of the remaining fat globules was reduced by approximately 10 nm after 60 min of sonication; however, the size of the casein micelles was determined to be unchanged. A small increase in soluble whey protein and a corresponding decrease in viscosity also occurred within the first few minutes of sonication, which could be attributed to the breakup of casein-whey protein aggregates. No measurable changes in free casein content could be detected in ultracentrifuged skim milk samples sonicated for up to 60 min. A small, temporary decrease in pH resulted from sonication; however, no measurable change in soluble calcium concentration was observed. Therefore, casein micelles in fresh skim milk were stable during the exposure to ultrasonication. Similar results were obtained for reconstituted micellar casein, whereas larger viscosity changes were observed as whey protein content was increased. Controlled application of ultrasound can be usefully applied to reverse process-induced protein aggregation without affecting the native state of casein micelles.