香蕉液氮低温排氧打浆技术研究

Study on the Banana Pulping Technique with Liquid Nitrogen Injection to Exclude Oxygen and Reduce Temperature

为抑制香蕉汁加工过程中的酶促褐变,采用自行研发设计的液氮排氧打浆机,对香蕉进行低温排氧打浆。对打浆时添加液氮后香蕉浆温度、溶解氧含量、果浆颜色以及多酚氧化酶(PPO)和过氧化物酶(POD)活力等的变化情况进行研究。结果表明:采用添加液氮排氧打浆技术,可以有效降低香蕉浆体的温度并驱排氧气,同时可降低PPO和POD酶活性及氧气含量(从10.3%下降到2.6%),有效防止酶促褐变和氧化。此外,由于液氮的冷冻效果,液氮打浆后浆体的出汁率(49.5%)远高于常温打浆的出汁率(14.2%)。在香蕉打浆过程中添加液氮,可以起到明显的防褐变作用,具有良好的应用前景。

In order to restrain enzyme promoting browning in banana juice process, a new liquid nitrogen pulper was designed for the banana pulping process with adding nitrogen to exclude oxygen and reduce temperature, the content of dissolved oxygen and the color were systemically studied, as well as the activity changes of polyphenoloxidase （PPO） and peroxidase （POD） during pulping process. It is showed that the banana slurry＇s temperature and the content of dissolve oxygen （From 10.3% to 2.6%）could be reduced markedly while adding the liquid nitrogen, the activity of PPO and POD were decreased also. Thus, the browning and oxidation of banana could be prevented during the process effectually. Furthermore, the banana juice yield of pulping with liquid nitrogen （49.5%） was much higher than pulping in normal temperature （14.2%） due to freezing impact by liquid nitrogen. The banana pulping process with adding liquid nitrogen can prevent browning obviously and have favorable application future.