研究去壳及带壳白煮蛋在冷藏(4 ℃)和室温(25 ℃)贮藏过程中水分体积分数、氧化情况、质构及颜色等品质的变化,采用低场核磁共振、质构分析及扫描电子显微镜等技术分析样品的水分分布、质构特性和微观结构,通过测定羰基含量及硫代巴比妥酸反应产物含量反映蛋白质和脂肪氧化情况.结果表明:在贮藏过程中,白煮蛋蛋清和蛋黄的水分体积分数,尤其是不易流动水体积分数,随着贮藏时间的延长而减少(P＜0.05),蛋白及脂肪氧化程度逐渐增加,去壳处理是这些变化的重要影响因素;同时,白煮蛋硬度和咀嚼性随贮藏时间的延长逐渐增加,凝胶微观结构更加致密,感官品质下降,但在所有实验组中,4 ℃带壳贮藏的白煮蛋品质变化幅度最小;贮藏温度对白煮蛋颜色无显著影响(P＞0.05),但去壳处理使得白煮蛋颜色发生显著变化(P＜0.05).综合分析表明,白煮蛋在贮藏中水分的损失和氧化是导致其品质下降的重要原因,带壳冷藏是白煮蛋较好的贮藏条件.%In this paper, the changes in moisture content, oxidation condition, texture and color of boiled eggs with and without shell were studied during storage at refrigerator (4 ℃) and room temperature (25 ℃), respectively. The moisture distribution, microstructure change and textural properties were determined using low field nuclear magnetic resonance, scanning electron microscopy and texture analyzer. The effects of protein and fat oxidation on the quality change were studied through carbonyl content and thiobarbituric acid reactive substances content. The results indicated that the moisture content in white and yolk of boiled eggs, especially immobile water content, was decreased during storage (P < 0.05), but the degree of protein and fat oxidation was increased, and shelling treatment was an important factor affecting these changes. At the same time, the hardness and chewiness of boiled egg increased gradually as the storage time was prolonged. The microstructure of egg white gel was denser and the sensory quality was lower than that of freshly boiled egg white gel, but the quality of boiled egg white with shell at refrigerator temperature (4 ℃) changed minimally among all experimental groups. Storage temperature had no significant effect on the color of boiled eggs (P > 0.05), but shelling treatment could change the color of boiled eggs significantly (P < 0.05). On the basis of the above results, the moisture loss and oxidization of boiled eggs were the major reasons for egg quality deterioration. In conclusion, storage at 4 ℃ is recommended for boiled eggs with shell.
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