Paula Vilela Tatiana, Gomes Ana Maria, Ferreira João Paulo
Universidade Católica Portuguesa, CBQF - Centro de Biotecnologia e Química Fina - Laboratório Associado, Escola Superior de Biotecnologia, Rua Diogo Botelho 1327, 4169-005, Porto, Portugal.
Curr Res Food Sci. 2020 Jul 18;3:201-206. doi: 10.1016/j.crfs.2020.07.001. eCollection 2020 Nov.
Interactions holding protein structure in cheese has been a subject of considerable investigation, with conclusions varying among studies. We present a review on this topic, covering fresh curds, ripened cheeses, and processed cheeses. We discuss the usual chemicals and conditions used to probe different types of interactions. Furthermore, we did our own study with solutions of urea, SDS, EDTA, NaCl, and NaOH, at different concentrations and combinations, for Emmental cheese. To quantify solubilized protein, we developed a modification of a spectrometric-based method that can be conveniently employed to quantify total protein in cheese, with statistically similar results to those obtained by the Kjeldahl method. Our results point out that caseins in the Emmental cheese are held together by a set of hydrophobic interactions, hydrogen bonds, and other electrostatic ones, including ionic bonds. Hydrogen bonds seem to have an important role, comparable to hydrophobic interactions, a conclusion not commonly reported for cheese structures.
维持奶酪中蛋白质结构的相互作用一直是大量研究的主题，不同研究得出的结论各异。我们针对此主题进行了综述，涵盖新鲜凝乳、成熟奶酪和加工奶酪。我们讨论了用于探究不同类型相互作用的常用化学物质和条件。此外，我们针对埃门塔尔奶酪，用不同浓度及组合的尿素、十二烷基硫酸钠、乙二胺四乙酸、氯化钠和氢氧化钠溶液开展了自己的研究。为了定量溶解的蛋白质，我们对一种基于光谱法的方法进行了改进，该方法可方便地用于定量奶酪中的总蛋白质，其统计结果与凯氏定氮法所得结果相似。我们的结果指出，埃门塔尔奶酪中的酪蛋白通过一组疏水相互作用、氢键和其他静电相互作用（包括离子键）维系在一起。氢键似乎起着重要作用，与疏水相互作用相当，这一结论在奶酪结构方面并不常见。
