添加山茶油对肌原纤维蛋白凝胶特性的影响

【目的】研究山茶油添加对凝胶中肌原纤维蛋白(myofibrillar protein,MP)特性的影响以及结构与凝胶特性间的关系,为其在鸡肉糜类制品中的应用提供理论依据。【方法】取鸡胸肉于4℃下提取MP,在添加山茶油条件下测定其流变特性,水浴加热制成凝胶后测定其硬度、保水性和水分布特性的变化;通过扫描电镜、激光拉曼光谱、表面疏水性(S0-ANS)、总巯基含量、差示扫描量热法(DSC)等分析,探讨山茶油对MP凝胶微观结构、二级和三级结构以及热变性的影响,并分析山茶油添加量、凝胶特性和MP结构之间的相关性,揭示山茶油添加促使凝胶特性改变的原因。【结果】MP凝胶的硬度、保水性和束缚水的百分比(PT21)随着山茶油添加量的增加而显著提高(P<0.05),在4%时分别达到最大值116.60 g、95.77%和80.05%,5%时有所下降。山茶油添加量为4%时,MP加热过程中的储能模量(G’)最高,凝胶弹性最大,此时扫描电镜下的MP混合凝胶网络结构均匀、致密,表面粗糙度最低。山茶油的添加(0-5%)影响MP的二级结构,其α-螺旋含量从39.94%显著降低至26.07%(P<0.05),...

Effects of Camellia Oil on the Properties of Myofibrillar Protein Gel

【Objective】The effects of camellia oil addition on the properties and the relationship between the properties and structure of myofibrillar protein (MP) gel were studied. The purpose of the research was to provide a theoretical basis for the application of camellia oil in chicken products. 【Method】The MP was extracted from chicken breast at 4℃. The MP heat-induced gels in different camellia oil addition were prepared. The changes of hardness, water holding capacity (WHC), moisture distribution of MP gel and rheological properties of MP were measured. Furthermore, the effects of camellia oil on the microstructure, secondary structure were determined by scanning electron microscopy (SEM) and Raman spectroscopy, respectively. Surface hydrophobicity and total sulfhydryl content were used to study the tertiary structure of MP in gels. Meanwhile, the differential scanning calorimetry (DSC) was applied to characterize the thermal properties of MP. Finally, the correlation between camellia oil addition, gel properties and MP structures were analyzed. 【Result】After 4% camellia oil addition, the hardness, WHC and the area fraction of bound water (PT₂₁) of MP gel increased and reached to maximum values of 116.60 g, 95.77% and 80.05%, respectively. However, those values decreased as camellia oil addition increased to 5%. For camellia oil content of 4%, the storage modulus (G') and elasticity of MP were the highest, while the surface roughness was the lowest. Meanwhile, MP gels showed more uniform, and compact network structure compared with other groups. It was also found that secondary structure of MP was significantly affected by camellia oil addition (0-5%). The α-helix content decreased from 39.94% to 26.07%, and the β-sheet content increased from 22.04% to 27.40% with increased camellia oil addition (P<0.05). The content of β-turn and random coil showed increasing trends. The S₀-ANS of MP reached the highest value, and the total sulfhydryl content was the lowest after 4% camellia oil addition. The results showed that the addition of camellia oil promoted the exposure of hydrophobic amino acid residues in protein molecules and the formation of disulfide bond, and changed the tertiary structure of MP in gels. The enhanced aggregation and cross-linking between MP molecules were due to the higher β-sheet content and hydrophobic interaction. The correlation analysis indicated that camellia oil addition was significantly correlated with the changes in the gel properties and protein structure (P<0.05). The results of DSC showed that camellia oil could interact with MP and reduce the denaturation enthalpy of MP. 【Conclusion】The camellia oil addition had a significant effect on the gel properties and structures of MP. The addition of camellia oil changed the microenvironment of MP and interacted with MP, which made the degeneration of MP easier. The secondary structure of MP was unfolded and the tertiary structure was affected after camellia oil addition, which improved the properties of MP gel. When camellia oil concentration was 4%, the properties and three-dimensional network structure of MP composite gel were the best.