黃酸樹膠/水/阿拉伯膠系統之液晶相圖研究

Phase diagrams of xanthan gum/water/arabic gum systems

李建蓉(Jenny Chien-Jung Lee)

指導教授 ： 芮祥鵬

國立臺北科技大學/工程學院/有機高分子研究所/碩士(2014年)

https://doi.org/10.6841/NTUT.2014.00161

摘要

黃酸樹膠(Xanthan gum)是一種高分子多醣體帶有陰電性的性質和特殊流變性質。因不同的溫度和不同的pH， 黃酸樹膠的結構會變。然而在不同的濃度下，黃酸樹膠也會有不同的性質，像是在膠狀的時候它會形成液晶態。阿拉伯膠是一種酸性異元多醣體，具有2%蛋白質。 也因為有這樣的特質， 它是一個很好的乳化劑。 因為阿拉伯膠具有小的流體力學體積，所以它的黏度較低。這兩種多醣體常被運用在食品、製藥、化妝品及其他工業上。

本實驗分成兩部分: 第一部分得到的相圖是先把兩個材料混合後，再跟去離子水攪伴。 第二部分所得到的相圖是先把黃酸樹膠跟去離子水攪伴，然後再把阿拉伯膠攪拌進去。 兩個部分皆用偏光顯微鏡去觀察。第一個相圖可以觀察到在黃酸樹膠濃高的區域是呈現典型的液晶相，在阿拉伯膠高濃度的區域是呈現分散性的液晶相。在第二個相圖可以觀察到在黃酸樹膠濃度高的區域是呈現典型的液晶相，在阿拉伯膠高濃度的區域是呈現鏈狀的液晶相。

關鍵字

黃酸樹膠 ； 阿拉伯膠 ； 液晶

並列摘要

Xanthan gum is an anionic polysaccharide that has exceptional rheological properties. Its structure can be affected by temperatures and pH differences. And at different polymer concentrations, it has different properties. For example at gel condition, liquid crystal phase was observed. Arabic gum is complex acidic branched heteropolysaccharide that contains 2% protein. And because of it, it is an excellent emulsifier. Arabic gum solution also has low viscosity because of its small hydrodynamic volume. Both polysaccharides are utilized in many different industrial processes, such as pharmaceutical, cosmetics, food industries.

In this research, xanthan gum and arabic gum were mixed in two different ways, and this resulted the formation of two different phase diagrams. The first method was to dissolve two mixed materials with distilled water. The second method was to dissolve xanthan gum first, then arabic gum. Samples of both experiments were investigated by using polarized optical microscope. In the phase diagram of first method, typical liquid crystal phase appeared in xanthan gum-rich region and dispersed liquid crystal phase appeared in arabic gum-rich region. In the phase diagram of second method, typical liquid crystal phase appeared at xanthan gum-rich region and strand-like liquid crystal phase appeared in the arabic gum-rich region.

並列關鍵字

liquid crystals ； arabic gum ； xanthan gum

參考文獻

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