热处理对鱼肌原纤维蛋白结构及腥味物质结合能力的影响

Effects of Heat Treatment on the Structure of Myofibrillar Protein and Binding Ability with Fishy Odor Compounds

为了阐明热处理对鱼肌原纤维蛋白与腥味物质结合作用的影响,选取4种典型鱼腥味物质,建立肌原纤维蛋白-腥味物质相互作用体系。采用紫外、荧光和拉曼光谱结合顶空-气相色谱-质谱联用技术研究鱼糜一段式加热过程中肌原纤维蛋白结构及其与腥味物质结合能力的变化。结果表明,随着热处理时间的延长,肌原纤维蛋白溶液的浊度、表面疏水性、总巯基含量均呈先增加后下降的趋势(P<0.05),蛋白质内源荧光强度逐渐降低。加热时间在0~5 min范围内,α-螺旋含量显著下降(P<0.05),而β-折叠和β-转角的含量显著增加(P<0.05);当加热时间超过5 min后,α-螺旋含量又逐渐升高,β-折叠降低。热处理对醛类物质与肌原纤维蛋白的结合能力影响显著。在加热初期,肌原纤维蛋白结构展开,对醛类物质的结合能力显著增强(P<0.05),其中对己醛、庚醛和壬醛的结合能力均在加热5 min时达到最大值,对辛醛的结合能力在2 min时达到最大值;之后,随着加热时间的延长,结合能力显著减弱(P<0.05)。

The present work investigated the effects of heat treament on the interactions of myofibrillar protein with fishy odor compounds.Four typical fishy odor compounds were selected and the myofibrillar protein-fishy odor compounds system were established.The changes in the structures of myofibrillar protein and binding capacity with volatile compouns during one-stage heating process of surimi were determined by UV spectra,fluorescence spectroscopy,Raman spectroscopy and head-space sampling combined with gas chromatography-mass spectrometry(HS-GC-MS)technology.The results showed that the turbidity,surface hydrophobicity and total sulfhydryl content of myofibrillar protein solution increased first and then decreased with the extension of heat treatment time(P<0.05),and the endogenous fluorescence intensity of protein decreased gradually.Within 0-5 min of heating,the content ofα-helix decreased significantly(P<0.05),while theβ-sheet andβ-turn content increased obviously(P<0.05).Subsequently,the content ofα-helix increased and theβ-sheet decreased when the heating time exceeded 5 min.The binding capacity of volatile aldehydes to myofibrillar protein was significantly influenced by the heating treatment.At the initial stage of heating,the structure of myofibrillar protein was unfolded and the binding ability with the aldehydes was significantly enhanced(P<0.05).The binding capacity of hexanal,heptanal and nonanal reached the maximum at 5 min of heating,while that of octanal reached the maximum at 2 min.After that,the binding ability decreased significantly with the prolongation of heating time(P<0.05).