中文摘要：

【目的】研究超声波对肌原纤维蛋白凝胶化学作用力与保水性的影响,并探讨化学作用力与保水性之间的内在联系。【方法】取活AA鸡屠宰,提取肌原纤维蛋白（myofibrillar proteins,MP）,用不同超声时间处理MP并制成热诱导凝胶,运用凝胶中总巯基含量的变化来反应二硫键的形成;凝胶的表面疏水性S0和Zeta电位值来表征疏水作用力和静电斥力;用拉曼光谱的I850/I830比值大小反映凝胶氢键的变化;凝胶保水性用高速离心机测定。【结果】超声波处理0—6 min时,MP凝胶的总巯基含量随时间的增加而减少,活性巯基含量显著增加;处理6—15 min时,MP凝胶的总巯基以及活性巯基均随时间延长而显著减少,而对MP原料进行同样处理时,处理时间在0—6 min内,MP总巯基和活性巯基变化趋势与MP凝胶相同;超过9 min后,活性巯基和总巯基没有显著变化,且二者含量逐渐接近。表明短时间超声波处理促进了MP分子内部巯基转变成二硫键,长时间超声波处理和加热成胶的共同作用促进了活性巯基转变成二硫键。MP凝胶的表面疏水性先随超声时间延长从1 194.1显著上升到1 489.5（6 min）,随后逐渐降至1 230.8,表明超声波产生的空穴效应能够使MP分子内部疏水基团暴露到分子表面,但超过6 min后,增加的蛋白表面疏水性又被包裹在凝胶网络中。MP凝胶的Zeta电位绝对值随超声时间的增加从6.03显著增加到7.68（P〈0.05）,超过6 min后显著减少,表明超声波处理使MP分子逐渐展开,蛋白质分子间静电作用增强,但过度展开后对其形成凝胶的静电作用力不利。适度的超声时间（0—6 min）使MP凝胶的归一化强度I850/I830比值从0.9805增加至1.023（P〈0.05）,表明MP与水分子形成的＂蛋白-水分子＂氢键增多,6 min过后比值减少,蛋白与水分子之间的氢键减弱;超声波处理0—6 min后的MP凝胶保水性从47.5899%快速升至72.9855%（6 min）（P?

英文摘要：

[ Objective ] The influences of ultrasound on chemical forces and water holding capacity of myofibrillar protein （MP） gel were studied. The relationship between MP gel chemical forces and WHC was revealed. [Method] AA type broilers were slaughtered. The MP was extracted from breast muscle. The MP solution and heat induced gel in different ultrasound times were prepared. Total sulfhydryl group （SH） content changes of gel were used to reflect the formation of disulfide bond. Surface hydrophobicity and Zeta potential value of the gel were employed to present the hydrophobic interaction and electrostatic repulsion, respectively. The ratio of I850/I830 was used to show the hydrogen bonding changes of gel. Water holding capacity （WHC） of MP gel was calculated by high-speed centrifuge. [ Result] As the ultrasonic time （UT） increased （0-6 min）, the total SH contents of the MP gel decreased and reactive SH content significantly increased, at stronger UT （6-15 min）, the total SH and reactive SH contents all decreased. At short time （0-6 min）, the changing trends of MP and MP gel about the total SH and reactive SH content were the same, while the total SH and reactive SH contents of MP all had no significant changes （P〉 0.05） over 6 rain, suggesting that UT promoted internal SH of MP into disulfide bond for shorter time, and UT and heating gel for longer time work together to promote reactive SH into disulfide bond. Surface hydrophobicity of MP gels increased from l 194.1 to 1 489.5 （P〈0.05） and decreased from 1 489,5 to 1 230.8 at last, for the cavitation phenomenon induced by UT could bring the hydrophobic regions into the surface, while at UT〉6 min, the hydrophobic group was wrapped in the gel network. Zeta potential value of the gel changed from 6.03 to 7.68 （P〈0.05） （0-6 min） , and then decreased over 6 min, which showed that ultrasonic wave made protein molecular chain unfolding, negatively charged by exposure, resulting in the stronger electrostatic repulsion, whil