基于海藻糖保护的预烤冷冻面包贮藏品质改善的研究

Improvement of Storage Quality of Pre-baked Frozen Bread Based on Trehalose Protection

预烤冷冻面包以其方便快捷日益受到消费者的接受和喜爱,但在冷冻储运中由于温度的波动易造成品质下降。本研究以海藻糖为抗冻保护剂,考察了不同海藻糖添加量(0、0.2%、0.4%、0.6%、0.8%、1.0%)及不同冻融循环周次(0~5个周次的冻融处理)对复烤面包质构特性、热重特性、感官品质、气孔结构及微观结构的影响。结果表明,在0~5个冻融周次下,硬度、咀嚼性不断增加,弹性、回复性、黏聚性、整体接受度不断降低,海藻糖的添加有效地阻止了劣变的程度,海藻糖添加量为0.6%的改善效果最为显著;随着海藻糖含量的增加和冻融周期的增加,复烤面包重量百分比呈下降趋势,且在40~60℃区间内,其重量百分比减少明显加快,以0.6%~1.0%添加量的下降速率减缓较为显著。当海藻糖的添加量为0.6%时,面包芯横切面细腻、空隙均匀、组织状态好,气孔持气率和稳定性得以提高,蛋白网络连续,淀粉颗粒得以均匀包裹;随着冻融周期的变化,复烤面包的横切面表面变得干燥且不均匀,气孔结构变得疏松,面筋蛋白网络虽逐渐减少且不连续,但淀粉颗粒却得以被面筋网络较均匀包裹,并少有不完整。

Pre-baked frozen bread is increasingly accepted and loved by consumers because of its convenience,but the quality of frozen bread is easily degraded due to temperature fluctuation during storage and transportation.In this study,the effects of different amount of trehalose added(0,0.2%,0.4%,0.6%,0.8%,1.0%)and different freezing-thawing cycles(0~5 cycles of freezing-thawing treatment)on texture,thermogravimetric properties,sensory quality,stomatal structure and microstructure of rebaked bread were investigated.The results showed that hardness and chewiness increasing continuously,while elasticity,resilience,cohesion and overall acceptability decreasing continuously during 0~5 freezing-thawing cycles,the addition of trehalose could effectively prevent the deterioration degree,and the addition of 0.6%trehalose had the most significant improvement effect.With the increasing of trehalose content and freeze-thaw cycle,the weight percentage of rebaked bread showed a decreasing trend,and in the range of 40 to 60℃,the weight percentage of rebaked bread decreased significantly,with the decreasing rate of 0.6%~1.0%.When the amount of trehalose was 0.6%,the transverse section of bread core was fine,the pore space was uniform,the structure was good,the stomatal air holding rate and stability were improved,the protein network was continuous,and the starch particles were evenly wrapped.With the change of freezing-thawing cycle,the cross section surface of the rebaked bread became dry and uneven,and the stomatal structure became loose.Although the gluten network was gradually reduced and discontinuous,the starch particles were evenly wrapped by the gluten network and seldom incomplete.