冷熏对高白鲑理化性质及肌球蛋白构象的影响

以新疆塞里木湖高白鲑为研究对象,研究冷烟熏过程对鱼肉理化性质及肌球蛋白构象的影响。冷熏温度为(20±2)℃,发烟温度140℃,冷熏时间分别为0、6、12、18、24 h,研究冷熏鱼肉理化性质(含水率、水分活度、色泽、质构特性、TVB-N)及肌球蛋白构象(蛋白浓度、总巯基含量、Ca^2+-ATPase、表面疏水性)变化。研究结果表明,冷熏0~24h,鱼肉含水率由75.75%下降至53.03%,水分活度(Aw)由0.988下降至0.952;鱼肉亮度值(L^*)显著降低(P<0.05),红度值(a^*)缓慢增加,黄度值(b^*)显著增加(P<0.05);表征鱼肉质构特性的剪切力与韧性均呈明显上升趋势(P<0.05);鱼肉挥发性盐基氮(TVB-N)由9.81上升至14.23 mg/100g;肌球蛋白浓度、总巯基含量、Ca^2+-ATPase活性均显著降低(P<0.05),表面疏水性增加(P<0.05);综上,控制冷熏时间12~18 h有利于提高冷熏鱼肉品质,降低鱼肉肌球蛋白变性与氧化程度。该研究为特色淡水鱼冷熏制品开发与烟熏过程中蛋白氧化调控提供理论依据与技术参考。

Effects of cold smoking on physicochemical properties and myosin conformations of Coregonus peled

The effect of cold smoking treatment on the physicochemical properties and myosin conformations of Coregonus peled from Sayram Lake(Xinjiang, China) were studied. The parameters of cold smoking machine were set as(20±2)℃ of environment temperature and 140 ℃ of smoke temperature, respectively. Pre-treated Coregonus peled was subjected to different cold smoking duration(0, 6, 12, 18 and 24 h, respectively), and then the changes of its physicochemical properties(moisture content, water activity(Aw), color, texture and TVB-N content) were investigated;then myosin was extracted from treated fish muscle, and its conformation change(myosin content, total sulfhydryl content, Ca^2+-ATPase activity and surface hydrophobicity) was studied as well. During the 24 h of cold smoking treatment, the moisture content of fish muscle was significantly decreased from 75.75% to 53.03%(P<0.05), and the Aw was significantly decreased from 0.988 to 0.952. The value of lightness(L^*), redness(a^*) and yellowness(b^*) of fresh fish flesh was 58.64,-0.80 and 3.00, respectively. With the extension of smoking time, L^* was significantly decreased(P<0.05), a^* was slowly increased(P<0.05) and b^* was significantly increased(P<0.05), and finally thecolor of fish flesh was transferred from gloss white to yellowish-brown. Both the shear force and toughness of fish meat subjected to cold smoking treatment were obviously increased(P<0.05) with the prolongation of smoking time. Meanwhile, the TVB-N content of fish product was gradually increased from 9.81 to 14.43 mg/100 g after the cold smoking treatment(24 h), which met the country’s national safety standards.On the other hand, the content of extracted myosin from Coregonus peled muscle was significantly decreased(P<0.05) with the extension of smoking time, along with the decrease(P<0.05) of total sulfhydryl content and Ca^2+-ATPase activity. The surface hydrophobicity of extracted myosin was continually increased during smokingtreatment(P<0.05). The results suggested that cold smoking treatment could lead to the protein denaturation of fish, and the degree of protein denaturation was getting severer when the treated time was longer. Therefore, comprehensively considering the results of sensory evaluation, freshness, protein denaturation of cold-smoked Coregonus peled and economic cost and production period of fish processing, 12 h of cold smoking treatment could effectively obtain the superior quality of cold smoked Coregonus peled. This paper could provide a theoretical basis and technical guidance for the development of cold smoked special freshwater products and for the control of the protein oxidation of fish product during cold smoking processing.