Heat-induced Transparent Gel from Hen Egg Lysozyme by a Two-step Heating Method.
The effects of ionic strength and dithiothreitol concentration, a reducing agent, on the heat-induced gelation of a lysozyme solution were examined at pH 7. Two different heating methods were used, one involving single heating, and the other, a two-step heating process in which a sample solution was heated twice under different medium conditions. With 7.5 mM dithiothreitol, a 5% lysozyme solution gave a transparent sol, a transparent gel, a translucent gel and a turbid gel after a single heating with 0, 40, 50, and 60mM NaCI, respectively. When the transparent sol obtained without NaCI was reheated with 50mM NaCI, it produced a firm and transparent gel. This gel was at least 6 times harder than the transparent lysozyme gel obtained by the one-step heating method. High-resolution scanning electron microscopy showed that the transparent gel produced by the two-step heating method had a fine network of linear polymers composed of heat-denatured lysozyme molecules.
a Research Institute for Food Science , Kyoto University , Uji, Kyoto 611 , Japan.
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Tani
a Research Institute for Food Science , Kyoto University , Uji, Kyoto 611 , Japan.
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Murata
a Research Institute for Food Science , Kyoto University , Uji, Kyoto 611 , Japan.
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Higasa
a Research Institute for Food Science , Kyoto University , Uji, Kyoto 611 , Japan.|b Hitachi Instrument Engineering Co., Ltd. , Katsuta , Ibaraki 312 , Japan.
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Goto
a Research Institute for Food Science , Kyoto University , Uji, Kyoto 611 , Japan.
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Kitabatake
a Research Institute for Food Science , Kyoto University , Uji, Kyoto 611 , Japan.
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