Department of Food Science and Technology, Faculty of Agriculture, Urmia University, Urmia, Iran.
Department of Food Technology, Institute of Chemical Technologies, Iranian Research Organization for Science and Technology (IROST), Tehran, Iran.
J Food Sci Technol. 2014 Sep;51(9):2113-9. doi: 10.1007/s13197-012-0707-y. Epub 2012 May 3.
Gelation process of acid-induced casein gels was studied using response surface method (RSM). Ratio of casein to whey proteins, incubation and heating temperatures were independent variables. Final storage modulus (G') measured 200 min after the addition of glucono-δ-lactone and the gelation time i.e. the time at which G' of gels became greater than 1 Pa were the parameters studied. Incubation temperature strongly affected both parameters. The higher the incubation temperature, the lower was the G' and the shorter the gelation time. Increased heating temperature however, increased the G' but again shortened the gelation time. Increase in G' was attributed to the formation of disulphide cross-linkages between denatured whey proteins and casein chains; whilst the latter was legitimized by considering the higher isoelectric pH of whey proteins. Maximum response (G' = 268.93 Pa) was obtained at 2.7 % w/w, 25 °C and 90 °C for casein content, incubation and heating temperatures, respectively.
利用响应面法（RSM）研究了酸诱导的酪蛋白凝胶的胶凝过程。酪蛋白与乳清蛋白的比例、孵育和加热温度是独立变量。添加葡萄糖酸-δ-内酯 200 分钟后测量最终存储模量（G'），凝胶时间（即凝胶的 G'大于 1 Pa 的时间）是研究的参数。孵育温度强烈影响这两个参数。孵育温度越高，G'越低，凝胶时间越短。然而，加热温度的升高增加了 G'，但再次缩短了凝胶时间。G'的增加归因于变性乳清蛋白和酪蛋白链之间形成的二硫键交联；而考虑到乳清蛋白的等电 pH 值更高，后者是合理的。在酪蛋白含量、孵育和加热温度分别为 2.7%w/w、25°C 和 90°C 时，获得了最大响应（G'=268.93 Pa）。
