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匿名使用者
匿名使用者 發問時間: 科學化學 · 1 0 年前

單寧酸化學結構

我要寫單寧酸相關之文獻回顧

我在某文獻上看他的單寧酸學結構,說是分成Flavanol單體,縮合單寧(Condensed tannain)與水解單寧(Hydrolysable tannain)三類。

但在網路資料上,多分為縮合與水解兩種。

哪種說法較為正確呢?

不要給我網路資料了,只要告訴我這兩種哪種說法是對的

專家幫幫我吧!!

1 個解答

評分
  • 1 0 年前
    最佳解答

    1.以下這段說明單寧Tannin泛指分子量在500至3,000,且含有羥基(hydroxyl)及其它官能基如羰基(carboxyl)等,可以與蛋白質或其它巨型分子形成錯合物的許多分子

    the term is widely applied to any large polyphenolic compound containing sufficient hydroxyls and other suitable groups (such as carboxyls) to form strong complexes with proteins and other macromolecules. Tannins have molecular weights ranging from 500 to over 3,000.

    2.單寧通常被分為可水解單寧和縮合單寧

    Tannins are usually divided into hydrolyzable tannins and condensed tannins (proanthocyanidins).

    其結構(範例)如下:

    Base Unit:

    Gallic Acid

    Flavone

    Class/Polymer:

    Hydrolyzable Tannins

    Condensed Tannins

    3.可水解單寧Hydrolyzable Tannins

    在分子中心有一個多羥基碳水化合物,通常是D-葡萄糖,然後部份或全部與另一個酚基酯化

    水解單寧可被弱酸或弱鹼水解成碳水化合物和酚

    At the center of a hydrolyzable tannin molecule, there is a polyol carbohydrate (usually D-glucose). The hydroxyl groups of the carbohydrate are partially or totally esterified with phenolic groups such as gallic acid (in gallotannins) or ellagic acid (in ellagitannins). Hydrolyzable tannins are hydrolyzed by weak acids or weak bases to produce carbohydrate and phenolic acids.

    4.縮合單寧Condensed Tannins

    又稱為:前花青素(proanthocyanidins,PA)由2至50個(或更多)類黃酮素(flavonoids),以碳與碳間的鍵結所縮合而成,不能被水解

    可水解單寧以及多數縮合單寧都可溶於水

    但有些分子量很大的縮合單寧分子不溶於水

    Condensed tannins, also known as proanthocyanidins, are polymers of 2 to 50 (or more) flavonoid units that are joined by carbon-carbon bonds, which are not susceptible to being cleaved by hydrolysis. While hydrolyzable tannins and most condensed tannins are water soluble, some very large condensed tannins are insoluble.

    參考網頁:

    http://en.wikipedia.org/wiki/Tannin#_note-Bate-Smi...

    http://zh.wikipedia.org/wiki/%E5%8D%95%E5%AE%81%E9...

    http://www.ce.mit.edu.tw/bioeng7/91%E7%94%9F%E5%8C...

    2007-10-13 13:16:39 補充:

    原花青素(Proanthocyanidins)簡稱PC,屬生物類黃酮,含類黃酮基本結構為黃酮醇的烷化物[1],是葡萄籽中重要的多酚類物質,原花青素的單體是兒茶素,或另一異構體,本身不具有活性但結合為二聚體或三聚體則有很高的生物活性,2~4個聚合即為低聚原花青素(OPC),將五個聚體以上的稱為高聚體花青素(PPC)[2],然而葡萄籽中的原花青素是由2~17個單體聚合成不同型態的花青素。

    2007-10-13 13:17:18 補充:

    http://zh.wikipedia.org/wiki/%E8%8A%B1%E9%9D%92%E7...

    2007-10-13 23:05:14 補充:

    1.單寧Tannin泛指分子量在500至3,000,且含有羥基(hydroxyl)及其它官能基如羰基(carboxyl)等,可以與蛋白質或其它巨型分子形成錯合物的許多分子

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