贮藏温度对大平顶枣品质的影响

Effect of Storage Temperature on Quality Change of Dapingding Jujube

摘要:

为探究贮藏环境对大枣品质的影响，以朝阳大平顶枣为原料，在0 ℃、4 ℃、10 ℃、20 ℃温度下进行贮藏试验。通过测定贮藏过程中失重率、硬度、还原糖含量、可滴定酸含量的变化。结合低场核磁共振技术测定贮藏中水分的迁移，研究大枣的水分动态s变化的微观过程。结果表明：0 ℃和4 ℃低温贮藏能显著延缓大枣硬度的变化，抑制大枣贮藏期间失重率的增加。随着贮藏温度的降低，还原糖含量开始下降的时间延后。贮藏35 d时，0 ℃贮藏的大枣中可滴定酸含量分别比4 ℃、10 ℃、20 ℃的含量高9.90%、44.10%、54.50%。采用低场核磁共振技术检测大枣中水分迁移情况，测得自由水幅度下降顺序为20 ℃>10 ℃>4 ℃>0 ℃，温度越高，自由水在贮藏中的损失越多，下降的速率越快，从微观角度初探了大枣贮藏过程中变化机理。

Abstract:

To explore the effects of storage environment on the quality of jujube, the influence of different storage temperatures of 0 ℃, 4 ℃, 10 ℃, 20 ℃ on the quality change of Chaoyang Dapingding jujube was investigated by measuring fruit weight loss rate, hardness, reducing sugar content, and titratable acid content. Combined with low field nuclear magnetic resonance (NMR) technology, the water migration during the storage was determined and the microscopic process for the moisture dynamic variation was studied. The results showed that storage at 0 ℃ or 4 ℃significantly delayed the decline of fruit hardness and the increasing of fruit weight loss rate. The time of reducing sugar decrease was carry-forwarded as the temperature decreases. After 35 days, the content for the titratable acid under 0 ℃ was 9.90%, 44.10% and 54.50% higher than one under 4 ℃, 10 ℃ and 20 ℃, respectively. Low field nuclear magnetic resonance (NMR) spectra was used to detect the moisture migration of the jujube storage, in which the order of the amplitude of the free water was 20 ℃>10 ℃>4 ℃>0 ℃. It was found the higher storage temperature led to more loss of free water in the storage.