Texture and structure of pressure-shift-frozen agar gel with high visco-elasticity
Texture and structure of pressure-shift-frozen agar gel with high visco-elasticity
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DOI：
10.1016/j.foodhyd.2005.01.008
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发表时间：
2006-03-01
影响因子：
10.7
通讯作者：
Jibu, Y
中科院分区：
文献类型：
--
作者：
Fuchigami, M;Teramoto, A;Jibu, Y
为了确定蔗糖和高压冷冻的效果，比较了两种琼脂凝胶：高粘弹性的A凝胶和普通甜点凝胶B。含有0、5、10或20%蔗糖的琼脂凝胶在0.1-686兆帕和-20℃下冷冻，它们在加压过程中冻结，并在0.1、100、600和686兆帕和-20℃(冻结)下检测到放热峰。然而，在200 Mpa下，它们不会冻结，而是在释放压力的情况下冻结(压力变换-冻结)。因此，200 Mpa变压冻结的凝胶的水解量要小于其他压力下冻结的凝胶的水解量。此外，在0.1、100、600和686 Mpa下冷冻的0%蔗糖琼脂凝胶，由于脱水和体积收缩，与对照凝胶相比，外观有很大的差异。结果表明，凝胶的破裂应力降低，冰晶的应变和尺寸增大，质量下降。相反，由于快速冻结，200 Mpa变压冻结的A和B的质构和结构都好于其他常压(-20、-30或-80℃)冷冻的压力处理凝胶和凝胶。因此，变压冷冻法效果更好。但A的质构、结构和水解性略好于B。在凝胶中添加蔗糖可以有效地改善琼脂冻胶的质量。(C)2005爱思唯尔有限公司。保留所有权利。
To determine the effects of sucrose and high-pressure-freezing, two kinds of agar get were compared; A gel with high visco-elasticity and B gel, an ordinary dessert gel. Both agar gels with 0, 5, 10 or 20% sucrose were frozen at 0.1-686 MPa and -20 degrees C. They were frozen during pressurization, and exothermic peaks were detected at 0.1, 100, 600 and 686 MPa and -20 degrees C (freezing). However, at 200 MPa, they did not freeze but froze with released pressure (pressure-shift-freezing). Thus, the amount of syneresis from gel pressure-shift-frozen at 200 MPa was smaller than that from gel frozen at other pressures. Also, amount of syneresis from A was smaller than B. In addition, compared to control gels, the appearance of 0% sucrose-agar gels frozen at 0.1, 100, 600 and 686 MPa differed greatly due to syneresis and a volumetric shrinkage of the gel. It was apparent that the rupture stress of the gels decreased, strain and size of ice crystals increased and quality declined. Conversely, due to quick freezing, the texture and structure of both A and B pressure-shift-frozen at 200 MPa were better than the other pressure-treated gels and gels frozen in freezers (-20, -30 or -80 degrees C) at atmospheric pressure. Consequently, pressure-shift-freezing was more effective. However, texture, structure and syneresis of A were somewhat better than that of B. It was found that the addition of sucrose to the gel was effective in improving the quality of frozen agar gels. (c) 2005 Elsevier Ltd. All rights reserved.