鸡肉肌原纤维蛋白与食品胶混合凝胶特性及其形成作用力研究

鸡肉肌原纤维蛋白与食品胶混合凝胶特性及其形成作用力研究南京财经大学硕士学位论文鸡肉肌原纤维蛋白与食品胶混合凝胶特性及其形成作用力研究姓名:董秋颖申请学位级别:硕士专业:食品科学指导教师:杨玉玲2010-01摘要本论文主要包含四方面内容: (1)肌原纤维蛋白(MP)凝胶特性研究; (2) 肌原纤维蛋白-卡拉胶(MP-CAR)混合凝胶特性研究和微观结构观察;(3)MP 凝胶和 MP-CAR混合凝胶形成作用力研究;(4)MP-明胶混合凝胶特性研究。

第二章:提取鸡肉 MP,利用质构仪和流变仪研究 MP 浓度、pH 及离子强度对 MP凝胶质构特性和流变特性的影响。

通过实验发现,硬度、弹性及贮能模量 G’、损耗模量 G’’均随着蛋白质浓度的增加而增加;pH6.0 时,MP 的硬度和G’、G’’昀大;随着离子强度的增大,硬度、弹性及 G’、G’’也不断增大。

通过方差分析发现,MP 浓度和离子强度对凝胶硬度的影响极显著,pH 也对其影响显著;MP浓度和离子强度对凝胶弹性的影响显著,而 pH则无明显影响。

第三章:CAR 的添加可以明显提高 MP 样品硬度、弹性、G’、G’’,发现MP 和 CAR 之间存在相互作用;MP 和 MP 与 CAR 的相互作用是引起 G’、G’’增加的主要原因,而 CAR 本身的贡献较小。

且随着卡拉胶含量的增加,混合凝胶的硬度和 G’也不断增加,而卡拉胶含量对混合凝胶弹性的影响较小。

在pH6.0时,混合凝胶的硬度昀大;随着 pH 的增大,MP-CAR 样品的 G’不断减小。

进4 +一步采用 L 3 正交表试验,研究卡拉胶含量、pH、离子强度和[K ]对硬度和弹9+性的影响。

结果发现,各因素对混合凝胶硬度影响程度由大到小为:[K ]、离子+强度、卡拉胶含量、pH;对混合凝胶弹性影响程度由大到小为:[K ]、卡拉胶含+量、 pH、离子强度。

且在卡拉胶含量为 33.33%, pH6.0,离子强度 0.2, [K ] 0.10mol/L+时可以形成硬度较好的凝胶;卡拉胶含量33.33%,pH7.0,离子强度0.2,[K ]0.10mol/L 时可以形成弹性较好的凝胶。

通过电子显微镜观察发现,MP 和CAR能形成混合型凝胶,其中 MP 的形状发生了改变,CAR 通过依附在 MP 凝胶骨架上加强凝胶的结构。

第四章: 在MP及MP-CAR混合溶液中添加有关试剂改变凝胶形成的作用力,通过测定其凝胶特性,以探讨形成和维持凝胶的网络结构的作用力。

结果表明,添加DTT导致MP的硬度、弹性和G’均略有下降,而MP-CAR的硬度稍有增加,G’降低,但凝胶特性变化不明显,说明二硫键对凝胶形成的影响不大;添加SDS显著影响MP凝胶和MP-CAR混合凝胶的硬度和弹性,添加量超过6mmol/L 时MP甚至不能形成凝胶,说明疏水相互作用在凝胶形成中具有显著作用;添加尿素和盐酸胍能明显降低凝胶的硬度、弹性及G’,说明氢键对MP凝胶的形成也具有重要的影响;改变pH影响了静电相互作用,从而改变了凝胶的凝胶特性。

通过比较加入丙二醇含量对MP硬度的影响曲线趋势,发现在MP凝胶形成过程中疏I水相互作用的影响超过氢键的影响,而在混合凝胶中二者相比没有明显区别,说明二者同等重要。

第五章:以硬度、弹性和 G’为指标,研究 MP-明胶混合凝胶的凝胶特性。

研究发现,明胶的添加可以改善凝胶的弹性。

在 MP中添加少量明胶后,混合凝胶的硬度有所降低,而后随着明胶含量的增加,硬度不断增加。

随着 pH值的增4加混合凝胶的硬度也逐渐增大,而其 G’则逐渐减小。

采用 L 3 正交表进一步研9究明胶含量、pH 和离子强度对硬度和弹性的影响。

结果表明:影响混合凝胶硬度和弹性的主次因素依次为:明胶含量、pH、离子强度。

且在明胶含量 50.0%,pH6.0,离子强度 0.6时可以形成硬度较好的混合凝胶;在明胶含量 50.0%, pH7.0,离子强度 0.2时得到弹性较好的混合凝胶。

关键词:肌原纤维蛋白;卡拉胶;明胶;质构特性;流变特性;分子间作用力IIABSTRACTThe properties of myofibrillar protein MP, MP-Carrageenan CAR, and MP-Gelatin and the molecular interactions such as electrostatic interactions, disulfidebonds, hydrophibic interactions and hydrogen bonds were investigatedChapter two: The effects of MP concentration, pH and ionic strength I ontextural properties and rheological properties of MP gels were studied by texturalanalyzer and rheometer. Results indicated, hardness, springness, G’, G’’ increasedwith the MP concentration increased. The hardness and G’, G’’ of MP were highest atpH6.0. Hardness, springness, G’, G’’ increased when the ionic strength increased. MPconcentration and ionic strength influenced hardness and springness of MP gelssignificantly Chapter three: The addition of CAR increased the hardness, springness, G’, G’’of the MP samples. MP and the molecular interactions between MP and CAR were themain reason which caused G’, G’’ increased. The hardness and G’ increased as CARconcentration increased. The CAR concentration had little influence on springness ofMP-CAR gels. The hardness of MP-CAR mixed gels was highest at pH6.0. G’ of4MP-CAR samples decreased as pH increased. The orthogonal test L 3 was adopted9+to seek the effects of concentration of CAR, pH, ionic strength, [K ] on gel hardnessand springiness. The results showed that the factors which affected the hardness of the+mixed gels were in the order of [K ], ionic strength, concentration of CAR and pHfrom major to minor. The factors which affected the springiness of mixed gels were in+the order of [K ], concentration of CAR, pH and ionic strength. Concentration of+CAR 33.33%, pH 6.0, I 0.2, [K ] 0.10mol/L is the optimal combination for hardnessof MP-CAR mixed gels. Concentration of CAR 33.33%, pH 7.0, I 0.2, [K+]0.10mol/L is the optimal combination for springness of MP-CAR mixed gelsScanning electron micrograghs of MP gels and MP-CAR gels showed that CARenhanced the structure of MP gels via clinging to the MP gel network Chapter four: The molecular interactions in the formation of MP and MP-CAR gelation was investigated by determining the effects of the solvents on the propertiesof MP. The addition of DTT influenced formation of disulfide bond. And the changesof the properties of the MP gels and MP-CAR mixed gels were unobvious, so thedisulfide bond have little effect on the formation of MP and MP-CAR gelation IIIAddition of SDS influenced hardness and springness of the gels significantly. So thehydrophobic interactions have given great contribution to the formation of MP andMP-CAR gelation. The addition of urea and GuHCl decreased hardness springinessand G’ of the gels obviously. So the hydrogen bonds also have significant effect onthe formation of MP and MP-CAR gelation. pH influenced the electrostaticinteractions, and changed the properties of the gels. The effects of propanediolconcentration on hardness on MP gels and MP-CAR mixed gels were investigatedThe result showed that the influences of hydrophibic interactions were moreimportant than hydrogen bonds during the formation of MP gels. But, hydrophibicinteractions and hydrogen bonds both played an important part in MP-CAR gelsChapter five: The properties of the MP-Gelatin were studied. The hardness ofgelatin increased with the concentration of gelatin increased. The addition of gelatindecreased the hardness, but improved the springness. G’ decreased when theconcentration of gelatin increased. The hardness of MP-Gelatin increased and G’4decreased as pH increased. The orthogonal test L 3 was adopted to seek the effects9of concentration of gelatin, pH, ionic strength on gel hardness and springiness. Theresults showed that the factors which affected the hardness and springness of themixed gels were in the order of concentration of gelatin, pH and ionic strength frommajor to minor. Concentration of gelatin 50%, pH 6.0, I 0.6 is the optimalcombination for hardness of MP-gelatin mixed gels. Concentration of gelatin 50%,pH 7.0 and I 0.2 is the optimal combination for springness of MP-gelatin mixed gelsKey words: myofibrillar protein; carrageenan; gelatin; texture properties; rheologicalproperties; molecular interactionsIV符号及缩略语缩写词英文名称中文名称MP Myofibrillar Protein Isolate肌原纤维蛋白CARCarrageenan卡拉胶BSA Bovine Serum Albumin 牛血清蛋白G’Storage modulus 储能模量G’’ Loss modulus 弹性模量DTT Dithiothreitol二硫苏糖醇NEM N-EthylMaleimide N-乙基顺丁烯二酰亚胺SDSSodium Dodecylsulfate Polyacrylamide 十二烷基磺酸钠学位论文独创性声明本论文是我个人在导师指导下进行的研究工作及取得的研究成果。