【摘要】 为探究储运过程中冻融频次对冷冻新疆馕坯品质的影响，模拟设计冻融频次试验（0～4次），利用低场核磁共振仪、流变仪、扫描电子显微镜与傅里叶变换红外光谱仪等检测、分析冷冻新疆馕坯的水分结合状态、流变学特性、微观结构及蛋白质二级结构等的变化，并通过烘焙试验综合评价冷冻新疆馕坯的感官品质，考察其烘焙特性。结果表明：随着冻融频次增加，冷冻新疆馕坯拉伸强度与拉伸距离明显降低；其流变学特性（弹性模量G’与黏性模量G’’）呈明显下降趋势；其强结合水不断流失，弱结合水先下降后上升又下降，自由水略有增加；内部微观结构观察显示，冷冻新疆馕坯出现明显的空洞与凹痕；蛋白质内部β-折叠含量降低，β-转角含量增加，有序的蛋白质二级结构变得松散、无序；同时，反复冻融也会导致冷冻新疆馕坯烘焙特性降幅增大，包括馕坯比容降低、硬度升高、综合感官评分降低等，储运过程中冷冻新疆馕坯冻融频次不宜超过4次。更多还原

【Abstract】 The effect of freezing-thawing cycles(0-4) on the quality of frozen semifinished Xinjiang naan during storage and transportation was studied. The changes of moisture migration state,rheological properties,microstructure,and protein secondary structure of frozen semifinished Xinjiang naan in freezing-thawing cycles were measured by a low-field nuclear magnetic resonance instrument,a rheometer,a scanning electron microscope,and a Fourier infrared spectrometer,respectively. The sensory quality of Xinjiang naan was evaluated through baking experiments,on the basis of which the backing characteristics were analyzed. The results showed that with the increase in freezing-thawing cycles,the tensile strength,tensile distance,and rheologicalproperties(elastic modulus G’ and viscous modulus G’’) of frozen semifinished Xinjiang naan decreased significantly. The strongly bound water continuously decreased;the weakly bound water presented a decreasing-increasing-decreasing trend;and the free water increased slightly. As the freezing-thawing cycles increased,obvious voids and dents appeared in the frozen semifinished Xinjiang naan,and the protein secondary structure became loose and disordered with decreased β-sheets and increased β-turns. Moreover,repeated freezing-thawing led to a decrease in the specific volume,an increase in hardness,and a decrease in comprehensive sensory score. The results suggested that the freezing-thawing should not exceed 4 cycles for the frozen semifinished Xinjiang naan in storage and transportation.更多还原