Hayashi Y, Nagano S, Enomoto H, Li C-P, Sugimoto Y, Ibrahim H R, Hatta H, Takeda C, Aoki T
United Graduate School of Agricultural Sciences, Kagoshima Univ., Japan.
J Food Sci. 2009 Jan-Feb;74(1):C68-72. doi: 10.1111/j.1750-3841.2008.01019.x.
Egg white protein (EWP) was phosphorylated by dry-heating in the presence of pyrophosphate at pH 4 and 85 degrees C for 1 d, and the foaming properties of phosphorylated EWP (PP-EWP) were investigated. The phosphorus content of EWP increased to 0.71% as a result of phosphorylation. To estimate the foaming properties of EWP, the foams were prepared by 2 methods: bubbling of the 0.1% (w/v) protein solution and whipping of the 10% (w/w) protein solution with an electric mixer. The foaming power, which was defined as an initial conductivity of foam from 0.1% (w/v) protein solution, was a little higher in PP-EWP than in native EWP (N-EWP), and the foaming stability of PP-EWP was much higher than that of dry-heated EWP (DH-EWP) and N-EWP. The microscopic observation of foams from the 10% (w/w) solution showed that the foams of PP-EWP were finer and more uniform than those of N- and DH-EWP. Although there were no significant differences in the specific gravity and overrun of the foams between PP- and DH-EWP (P < 0.05), the specific gravity and overrun of the foams from PP-EWP were smaller and higher, respectively, than that of the foams from N-EWP. The drainage volume was smaller in the foams from PP-EWP than in those from N- and DH-EWP. These results demonstrated that phosphorylation of EWP by dry-heating in the presence of pyrophosphate improved the foaming properties, and that it was more effective for the foam stability than for the foam formation.
在pH值为4、85℃的条件下，于焦磷酸存在下对蛋清蛋白（EWP）进行干热磷酸化处理1天，然后研究了磷酸化蛋清蛋白（PP-EWP）的发泡性能。磷酸化后，EWP的磷含量增加至0.71%。为评估EWP的发泡性能，通过两种方法制备泡沫：将0.1%（w/v）的蛋白质溶液鼓泡，以及用电动搅拌器搅拌10%（w/w）的蛋白质溶液。发泡能力定义为0.1%（w/v）蛋白质溶液产生的泡沫的初始电导率，PP-EWP的发泡能力略高于天然EWP（N-EWP），且PP-EWP的发泡稳定性远高于干热EWP（DH-EWP）和N-EWP。对10%（w/w）溶液产生的泡沫进行显微镜观察表明，PP-EWP的泡沫比N-EWP和DH-EWP的泡沫更细且更均匀。尽管PP-EWP和DH-EWP的泡沫在比重和膨胀率方面无显著差异（P<0.05），但PP-EWP的泡沫比重分别小于N-EWP的泡沫，而膨胀率则高于N-EWP的泡沫。PP-EWP的泡沫排水体积小于N-EWP和DH-EWP的泡沫。这些结果表明，在焦磷酸存在下对EWP进行干热磷酸化可改善其发泡性能，且对泡沫稳定性的改善比对泡沫形成的改善更有效。
