中文摘要：

【目的】研究加热温度对肌原纤维蛋白二级结构和凝胶特性的影响，并探讨肌原纤维蛋白二级结构与凝胶特性之间的内在关系。【方法】将活AA鸡20只（40日龄）屠宰，取鸡胸肉在-18℃下储存，用于提取鸡胸肉肌原纤维蛋白。用圆二色谱（CD）研究加热过程中肌原纤维蛋白二级结构（α-螺旋，β-折叠，β-转角和无规则卷曲）的变化；使用流变仪测定加热温度对肌原纤维蛋白的流变性质参数储能模量G’和相位角正切值（Tanδ）的影响；将肌原纤维蛋白在不同温度下制备成凝胶，运用质构仪研究成胶温度对凝胶硬度和弹性的影响；用低场核磁共振仪（NMR）测定不同加热温度下成胶的肌原纤维蛋白凝胶的弛豫时间T2，以此研究不同温度下制得凝胶的水分布特性。利用SPSS17.0对所得的数据进行相关性分析等处理，以便阐明加热温度与肌原纤维蛋白二级结构及其凝胶特性的关系。【结果】加热温度显著影响肌原纤维蛋白的二级结构。随着加热温度升高，肌原纤维蛋白二级结构中α-螺旋含量逐渐降低。在30℃时α-螺旋含量为95.77%，加热温度在30-40℃以及70-80℃之间时α-螺旋含量变化很小，在40-70℃之间显著下降（P＜0.05），到80℃时下降到45.05%。β-折叠含量在30-45℃之间随温度上升缓慢增加，在40-70℃之间显著增加（P＜0.05），超过70℃后含量仅略有增加；在30-80℃加热范围内，β-折叠含量从0.20%增加到12.65%。α-螺旋含量降低代表蛋白质分子展开程度增加，而β-折叠含量增加代表蛋白质分子间聚集程度增加。加热温度影响肌原纤维蛋白的流变性、质构特性和水分布特性。G’开始增加时的温度为42℃，表明肌原纤维蛋白在此温度下开始胶凝。在42-50℃之间，G’迅速增加到峰值177 Pa，之后G’迅速下降（50-55℃），在55-75℃范围内G’再次快速增加；肌原纤?

英文摘要：

ObjectiveThis study was designed to investigate the influence of heating on myofibrillar proteins（MP） secondary structure and gel properties, and to reveal the relationship between MP secondary structure and gel properties.[Method]Forty-day-old commercial AA broilers were slaughtered. The breast muscle was stored at-18℃ before MP was extracted. The MP secondary structure was measured using a circular dichroism spectra to determine the content ofα-helix,β-sheet,β-turn and random coil during heating. The values of G＇ and Tanδ were continuously measured using a rheometer during heating. The influence of heating temperature on textural properties of MP gel prepared under different temperatures was measured using a textural analyzer. Spin-spin relaxation time （T2） of the gels prepared under different temperatures was measured using a NMR Analyzer in order to investigate the water distribution of gels. SPSS17.0 software was used to analyze the data such as correlation analysis so as to illustrate the relationship between the heating temperature and protein structure and gel properties. [Result] Heating temperature influenced significantly MP secondary structure. Theα-helix content declined from 95.77%to 45.05%as temperature increased from 30℃ to 80℃. Theα-helix content declined slightly as temperature increased from 30℃ to 40℃ and from 70℃ to 80℃, declined abruptly between 40℃ and 70℃ （P〈0.05）. The β-sheet content increased from 0.20% to 12.65% as temperature increased from 30℃ to 80℃. The decline inα-helix content indicates the unfolding of a protein molecule. The increase inβ-sheet content indicates the aggregation of unfolding protein molecules. Heating temperature influenced rheological properties, textural properties and water distribution of MP. G＇ values began to increase at about 42℃ indicating the starting of protein gelling. G’ values showed a sharp increase between 42℃ and 50℃ （177 Pa） with a subsequent decrease between 50℃ and 55℃ and a final