School of Chemistry/Department of Chemical and Biomolecular Engineering, University of Melbourne, VIC 3010, Australia.
J Dairy Res. 2013 May;80(2):138-43. doi: 10.1017/S0022029912000696. Epub 2013 Jan 18.
Gelation is a significant operation in dairy processing. Protein gelation can be affected by several factors such as temperature, pH, or enzyme addition. Recently, the use of ultrasonication has been shown to have a significant impact on the formation of whey protein gels. In this work, the effect of ultrasonication on the gelation of casein systems was investigated. Gels were formed by the addition of 7.6 mm Tetra Sodium Pyro Phosphate (TSPP) to 5 wt% micellar casein (MC) solutions. Sonication at 20 KHz and 31 W for up to 30 min changed the surface hydrophobicity of the proteins, whereas surface charge was unaltered. Sonication before the addition of TSPP formed a firm gel with a fine protein network and low syneresis. Conversely, sonication after TSPP addition led to an inconsistent weak-gel-like structure with high syneresis. Gel strength in both cases increased significantly after short sonication times, while the viscoelastic properties were less affected. Overall, the results showed that ultrasonication can have a significant effect on the final gel properties of casein systems.
胶凝作用是乳制品加工中的一项重要操作。蛋白质胶凝作用会受到温度、pH 值或酶添加等多种因素的影响。最近，超声处理的应用已被证明对乳清蛋白凝胶的形成有显著影响。在这项工作中，研究了超声处理对酪蛋白体系胶凝作用的影响。通过向 5wt%胶束酪蛋白（MC）溶液中添加 7.6mm 四磷酸钠（TSPP）形成凝胶。在 20KHz 和 31W 的条件下超声处理长达 30 分钟会改变蛋白质的表面疏水性，而表面电荷则保持不变。在添加 TSPP 之前进行超声处理会形成具有细蛋白质网络和低持水能力的坚固凝胶。相反，在添加 TSPP 之后进行超声处理会导致持水能力高的不一致的弱凝胶状结构。在两种情况下，短时间超声处理后凝胶强度都会显著增加，而粘弹性则受影响较小。总的来说，结果表明超声处理对酪蛋白体系的最终凝胶性能有显著影响。
