鸡蛋新鲜度与其挥发性有机化合物间的关系研究

Relationship Research for Freshness of Eggs and Its Volatile Orgnic Compounds

采用顶空固相微萃取-气相色谱-质谱联用技术分析不同新鲜度的伊莎褐鸡蛋的挥发性化合物的变化,同时分析鸡蛋的哈夫单位、蛋黄指数和气室指数等新鲜度指标,探讨鸡蛋挥发性化合物与新鲜度的关系。新鲜鸡蛋的特征性气味化合物为1-甲基-4-（1-甲基乙基）-3-环己烯-1-醇和5,5,6-三甲基-双环[2.2.1]庚烷-2-酮,其含量分别为5.203,3.374μg/L。35℃时鸡蛋保鲜时间为3 d,（4±2）℃时保鲜时间21-35 d。鸡蛋由新鲜变为不新鲜时的主要挥发性化合物为2,6,10,14-四甲基-十五烷和二丁基羟基甲苯,其变化阈值分别为5.442μg/L和8.377μg/L。鸡蛋气室指数的变化趋势与哈夫单位基本呈手性对称,表明可用气室指数代替哈夫单位评价鸡蛋的新鲜度。

The volatile orgnic compounds of Isa Brown eggs under different freshness were researched, by headspace solid-phase micro extraction-gas chromatography-mass spectrometry（HS-SPME-GC-MS）, simultaneously, the Haugh unit, yolk index and air space index（ACI） of these eggs were analyzed to obtain the relationship between freshness of eggs and its volatile orgnic compounds. The characteristic odor compounds of fresh eggs are 1-methyl-4-（1-methylethyl）-3-Cyclohexen-1-ol and 5,5,6-trimethyl-bicycle[2.2.1] heptan-2-one, which content are 5.203 μg/L, 3.374 μg/L respectively. Maintained fresh time of eggs is 3 days at 35 ℃, and is greater than 21 d and less than 36 d at 4 ℃±2 ℃. The main volatile orgnic compounds of eggs derived from fresh to not fresh are 2,6,10,14-tetramethyl-pentadecane, and butylated hydroxy toluene（BHT）. When the volatile orgnic compounds of 2,6,10,14-tetramethyl-pentadecane and BHT reached to 5.442 μg/L and 8.377 μg/L, respectively, the fresh eggs began to become spoiled. Furthermore, Trends of ACI and Haugh units of eggs is substantially showing chiral symmetry, which indicates that ACI can replace Haugh units to evaluation eggs＇ freshness.