桃汁贮藏期间的品质变化研究

The Quality Change of Peach Juice during Storage

摘要:

为探讨桃汁贮藏期间品质的变化，将鲜桃汁灭菌后分别贮藏在4 ℃、25 ℃和37 ℃下，检测并分析桃汁贮藏期间的理化指标、营养成分和香气成分的变化。发现在4 ℃、25 ℃和37 ℃下，桃汁的褐变度分别增加了0.14、0.33和0.56；总糖分别降解了49.06%、53.59%和57.19%；维生素C分别降解了46.27%、43.05%和51.06%；蛋白质分别降解了31.82%、57.14%和64.00%；总酸含量变化很小。桃汁在贮藏过程中，贮藏温度和贮藏时间对褐变度、总糖、维生素C、蛋白质、总酚、果胶等含量的变化均有极显著影响(p<0.01)。在对桃汁贮藏期间香气成分变化的研究中，共鉴定出35种香气成分。新鲜桃汁具有较好的香气，其特征香气十一烷-4-内酯达到1.25%，5-癸内酯达到4.45%。贮藏40 d后，4 ℃下鉴定出的香气成分占总质量分数的79.90%，25 ℃下鉴定出的香气成分占总质量分数的60.14%，37 ℃下鉴定出的香气成分占总质量分数的54.59%。因此，低温贮藏有助于桃汁品质地保持。

Abstract:

To study the effect of storage conditions on the quality changes of peach juice pretreated by sterilization, the experiments were carried out at three storage temperatures of 4, 25 and 37 ℃. The changes of physical and chemical indicators, nutrients and aroma components during storage were tested and analyzed. The result showed that browning degree index was increased by 0.14, 0.33 and 0.56 at the three different temperatures, respectively. The total sugar contents of the three samples were decreased by 49.06%, 53.59% and 57.19%, respectively. The vitamin C contents were 46.27%, 43.05% and 51.06%, and the protein contents were 31.82%, 57.14% and 64.00% respectively. There was no significant change in the total acid contents before and after storage, while the effect of storage time and temperature on the browning degree, pH, total sugar, Vitamin C, protein, total phenol and pectin content were highly remarkable (p < 0.01). Thirty-five aroma compositions were identified in the peach juice. The fresh juice had good aroma, and the characterized flavor undecan-4-olideand 5-decanolide reached 1.25% and 4.45%. After 40 days storage, the amount of identified aroma components declined to 79.90%, 60.14% and 54.59% of the total mass fraction at 4, 25 and 37 ℃, respectively. Therefore, low temperature storage could keep the quality of peach juice.