• 作者： 曾浩洋
• 作者服務機構： 國立中興大學食品科學系
• 中文摘要： 葡萄柚 (Citrus paradisi, Macf.) 果汁在美國為消費量佔第二位之天然果汁，其苦味成分之
  主要為柚苦? (Naringin)。若能過當控制此苦味成分之含量，以適合部分國人之口味，則應可在
  木省推廣此類果汁。欲適當控制此種苦味成分之含量，可使用合乎經濟性之蟹殼幾丁質(Chitin)
  作擔體，以戊二醛(Glutaraldehyde)及硼氫化鈉(Sodium borohydride)共同作用，將柚苦?
  分解酵素(Naringinase)加以不溶性化，其最佳酵素固定率可達50%左右。此種不溶性酵素
  Chitin-naringinase 之最適 pH 值在 4.5～5.0 之間，略高於可溶性酵素，而其最適反應溫度則
  為47°C。以此固定化酵素製成之酵素反應器連續用於柚苦?溶液之苦味去除時，其酵素穩定性
  比以 DEAE-Sephadex-A25 固定化之酵素為佳。然而，當應用於葡萄柚原汁之苦味去除研究時
  ，二者之酵素活性，都有降低之趨勢，而且呈現不穩定之現象，其原因在本報告中將詳細討論
  之。
  n
• 英文摘要： Consumption of the grapefruit (Citrus para-disi, Macf.) juice is rated as the second for allthe natural juices now available in the UnitedStates. The bitterness of this juice is mainly dueto the constituent of naringin. If the content ofnaringin in the grapefruit juice can be optimallycontrolled, this juice may become one of thepopular fruit juices in Taiwan. In order tocontrol the naringin content in the fruit juice,the naringinase was immobilized on the chitinprepared from the crab shell and then used forthe controlled hydrolysis of the naringin in thefruit juice. Immobilization of the naringinase to thechitin could be carried out by reactions requiringglutaraldehyde and sodium borohydride. Themaximum enzyme yield was 50% approximately.The optimal pH for the insoluble chitin-naringinase was between 4.5 and 5.0, somewhathigher than that of the native soluble enzyme.The optimal temperature for this immobilizednaringinase was approximately 47°C. When theenzyme column made with chitin-naringinasewas continuously used for the hydrolysis ofnaringin solution in McIlvaine buffer of pH 3or 4, the enzyme activity was much more stablein comparison with the enzyme column madewith DEAF-Sephadex-naringinase. However, asthe enzyme columns were continuously used forthe debittering of grapefruit juice, the enzymeactivities in both columns were rather unstable.Possible explanations and some discussions weregiven in this report.
• 中文關鍵字： --
• 英文關鍵字： --