蓮藕澱粉顆粒結構之不均勻性與其衍生應用

Heterogeneity of lotus rhizome starch granule organization and its derivative applications

林惠美(Hui-Mei Lin)

指導教授 ： 許明仁

共同指導教授 ： 呂廷璋(Ting-jan Lu)

國立臺灣大學/生物資源暨農學院/園藝學研究所/博士(2004年)

https://doi.org/10.6342/NTU.2004.01585

摘要

蓮是台灣重要經濟作物之一，所含之蓮藕澱粉顆粒呈長橢圓外觀，澱粉臍的位置接近於長橢圓形的一端，以酵素降解部分結構之後，顆粒二端型態截然不同，推測澱粉顆粒之結構分布不均勻所致，本研究利用細菌來源的澱粉液化酶，降解分離自台灣生產的蓮藕之澱粉顆粒，以澱粉臍的位置作為定位指標，發現酵素由相對於澱粉臍的另一端開始作用，並在顆粒內部形成類似魚骨狀的空穴。酵素開始作用的一端，以及顆粒中心是結構上分子排列比較鬆散的區域，因此形成結構上的弱點，對酵素降解反應有較高的感受性。而酵素對於直鏈澱粉分子與支鏈澱粉分子，或是顆粒中的結晶區與非結晶區並沒有明顯的選擇性降解，本論文首次以酵素降解反應觀察到蓮藕澱粉顆粒在結構上的不均勻特性。另外，分析來自二十四種不同來源澱粉顆粒對於酵素降解的感受性，也發現澱粉的顆粒結構的不均勻性質影響酵素在顆粒內的侵蝕途徑，造成顆粒在酵素降解前後的型態改變，其影響並且反應在酵素反應的速率變化。蓮藕澱粉在酵素降解前後的獨特型態，與其對酵素降解的感受性，可藉由光學顯微鏡與簡易的分析而與大部分的市售澱粉做區分，對於蓮的主要加工產品–藕粉的判別可作為參考指標。酵素侵蝕部分結構後，澱粉顆粒產生或增大特定型態的孔洞與空腔，這些孔洞的累計體積隨著降解率的提高而增加，吸附能力也隨之提高，具有開發為生物來源之多孔性材質的潛力。

關鍵字

蓮藕 ； 蓮藕粉 ； 澱粉 ； 澱粉顆粒結構 ； 澱粉分子 ； 酵素降解 ； 澱粉液化酶非均勻性 ； 型態 ； 孔洞狀澱粉 ； 吸附 ； 分子篩層析

並列摘要

Lotus (Nelumbo nucifera Gaertn.) is one of the important crops in Taiwan. Most of lotus rhizome starch granules had an elongated oval shape with the hilum located close to the end. The morphologic characteristics of two ends of the granule were different after enzyme partial degradation. It indicated that the molecular organization of two ends was heterogeneous. In this study, the lotus rhizome starch granules were partially degraded by bacterial α-amylase (Bacillus sp.). Using the hilum location as a direction anchor, it was found that the enzyme degraded from the end distant from the hilum and formed a fish-bone like cavity in the granule. The enzyme attacked end and the central part of the granule were the regions that the molecular organization were loosely packed, and became the weak points with higher susceptibility to the enzyme degradation. The selectivity of α-amylase hydrolysis was low for the crystalline and amorphous regions and for amylose and amylopectin molecules. The heterogeneity of the starch organization was first time revealed by using enzyme degradation. This heterogeneity of the granules was found to be stongly correlated with the α-amylase degrading patterns and the morphology of the remaining granules, after studied 24 different sources of starch granules. It was also proposed as a kinetic affecting factor for starch granule degradation by the α-amylase. The unique morphology of lotus rhizome starch and susceptibility of enzyme reaction can be viewed under light microscope and analyzed by the simple operation. It can be applied to recognized lotus rhizome starch from other commercial starches. The enzyme degradation formed or enlarged the pores and cavity in the granules. It increased the cumulative volume of the pores and improved the adsorption capacity of the granules. The enzyme degraded granule showed the potential to be a new biological material in industries.

並列關鍵字

lotus rhizome ； lotus flour ； starch ； starch granule organization ； starch molecule ； enzyme hydrolysis ； alpha-amylase ； heterogeneity ； morphology ； porous starch ； adsorption ； HPSEC

參考文獻

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