Microsoft PowerPoint - 碳水化合物1.ppt

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1 食品化學 Food Chemistry 碳水化合物 Carbohydrate 鄭心嫻教授 (96) 1 Food Chemistry Fennema OR 2 1

2 一重點 1. 以化學角度説明食物中組成與色香味之相關 2. 單醣多醣種類及其衍生物之認識 3. 單醣性質結構分類方法及在食品中的應用 4. 瞭解寡醣和多醣的理化性質生理功能以及在食品加工中的應用 5. 幾種重要多醣的結構性質及其在食品加工和儲藏中的作用 3 二前言 They are, widely available, and. As natural component as added ingredients in food Nontoxic They are also > 90% of the dry matter of plants. 4 2

3 Many different structures, size Exhibit a variety of and properties. 5 Modification Chemical and modification Improving their properties and their use 6 3

4 Cx(H2O)n 碳水化合物 Living organisms do not have this simple empirical formula ( ) Oligosaccharides ( ) Polysaccharides ( ) 7 例外 : Cx(H2O)n 非醣類 : (HCHO) (CH3COOH) (C H3CHOHCOOH) 8 4

5 Monosaccharides (simple sugars) are carbohydrate molecules that cannot be down to simpler carbohydrate molecules by. They can be joined to form larger structures (oligosaccharides and polysaccharides) 9 Lower molecular weight carbohydrates are often obtained by depolymerization ( ) of the natural polymers 10 5

6 Starch, lactose, sucrose Hydrolysis Digestible depolymerization D-glucose, D-fructose 11 三分類 D-glucose is both a alcohol and an aldehyde. It is classified as an, a designation for sugars containing an aldehyde group. The ending signifies a sugar; --signifies an aldehyde group 12 6

7 Table Classification of Monosaccharides Kind of group Number of Carbon atoms Tri Tri 4 Tetrose Tetrulose 5 Pentose Pentulose 6 Hexose Hexulose 7 Heptose Heptulsoe 8 Octose Octulose 9 Nonose Nonulose 依結構分 : 1. Monosaccharides pentoses : arabinose xylose ribose hexoses : fructose sorbose glucose galactose mannose 14 7

8 (1) 五碳醣 pentosan (a) L- 阿拉伯糖 (L- arabinose) a. 為多醣膠質果膠質半纖維素 (hemicellulose) 的基本組成分存在蘋果葡萄柚子等 b. 稀水解果肉 L- (b) D- 核糖 (D- ribose) 構成維生素 B 2 (riboflavin) 及細胞中 (ribose nucleic acid, RNA) (c) D- 木糖 (D-xylose) a. 存於之細胞半纖維素,(wood sugar) b. 甘蔗渣稻穀酸水解酵母菌 ( 去葡萄糖 ) D- c. 不能分解不產生熱能 ( 肥胖糖尿病適用 ) 15 (2) 六碳醣 (a) D- 葡萄糖 (D- glucose) a. 澱粉纖維素肝醣等的單位 b. 與果糖以狀態存在葡萄無花果中 c. 在代謝及產生上, 很重要 d. 水解澱粉 D- e. 甜度為之 65~75% f. 有食物功能 (>170 成為焦糖 caramel) (b) D- 果糖 (D-fructose) a. 為 (levurotation) 又稱左旋糖 b. 與糖以游離狀態存在果實中 ( 蘋果梨 ) c. 水解菊糖 D- 16 8

9 (c) D,L- 半乳糖 (D,L- galactose) a. 以狀態存在 b. 水解棉子糖得 D- 半乳糖 c. 洋菜中有 L - 半乳糖 (d) D- 甘露糖 (D-mannose ) 聚甘露糖存在膠質植物甘露糖醇存在菌類 Oligosaccharides lactose ( -galactose + glucose), 16%sucrose sweet maltose ( -glucose + glucose), 33%sucrose sweet sucrose ( -glucose + -fructose) ( 不具 ) (table sugar) 18 9

10 3. Polysaccharides (1) homopolysaccharides pentosans xylan( 聚木糖 ), arabinan, hexosans glucosans( 聚葡萄糖 ), starch cellulose, glycogen fructosan (inulin ) (2) heteropolysaccharides gum pectins 19 四單醣結構 1. 開鏈式 (open-chain form), (Fisher-Tollens formula) a. aldoses ( ) CHO (CHOH) n CH 2 OH 甘油醛, n = 1, D-, L- form b. ketoses ( ) CH 2 OH C O (CHOH) n CH 2 OH 20 10

11 c. uronic acid ( ) CHO (CHOH)n COOH d. sugar alcohol ( ) CH2OH (CHOH)n CH2OH 21 e. aldonic acid ( ) COOH (CHOH) n CH 2 OH f. aldaric acid ( ) COOH (CHOH) n COOH 22 11

12 g. amino sugar ( ) CHO H C NH 2 (CHOH) n CH 2 OH 23 醛醣 (, D-glyceraldehyde) CHO H C OH CH 2 OH (1) chiral ; asymmetric carbon atom 原子 (2) enantiomer ; mirror image isomer 物 (3)D-form (-OH 基在其 ) ( 自然界存在多醣 ) L-form (-OH 基在其左邊 ) 24 12

13 Wedges 楔形 Dashes - 不對稱 25 Chiral carbon atom 原子 different groups attached to them The two different arrangements of the four groups in space (configurations ) are nonsuperimposable( 他物上 ) mirror images of each other. Chemical bones ( 鍵 ): covalent bond ( 鍵 ) ionic bond ( 離子鍵 ) coordinate bond ( 配位鍵 ) 26 13

14 aldehyde group Hydroxyl group Hydroxyl group Hydroxyl group Hydroxyl group Hydroxyl group 開環 27 L-glucose: D-glucose has a molecular mirror ( 鏡像 )image, termed the L form, 28 14

15 Chiral carbon atom 原子 Each chiral carbon atom has a mirror image, there are arrangements for these atoms. Six-carbon aldose are 2 4 or different arrangements of the carbon atoms (containing secondary hydroxyl groups). (8 L-form; 8 D-form) 29 C-5 right-hand D-sugar (Shorthand way---rosanoff method) 30 15

16 31 D-glucose is the only free usually present in natural foods, and then only in small amounts 32 16

17 C-5 left-hand L-sugar L-sugar less in nature than the D-forms Two L-sugar found in food L- ; L- As units in carbohydrate (polysaccharides) (Fischer projection) 17

18 HOCH 異構化環狀式 (cyclic form) (Haworth formula) 醛基或酮基醇類 (hemiacetal) (acetal) e.g. 葡萄糖 (Fig. 9) -CHO 基 -OH 基 ( 第四 C 或第五 C) glucofuranose glucopyranose ( 五元環 )( ) ( 六元環 )( ) 36 18

19 Carbonyl ( )groups of aldehydes (ketone) are reactive and easily undergo nucleophilic ( )attach by the oxygen atom of a hydroxyl group to produce a hemiacetal. ( ) The hydroxyl group of a hemiacetal can react further (by condensation) with a hydroxy group of an alcohol to produce an Acetal ( ) (Fig. 6) 37 Carbonyl groups C=O Ketone group Aldehyde group Nucleophile ( ) 離子或分子能提供一對電子給原子核而形成共價鍵者稱之 Electrophile ( ) 接受電子之原子核稱之 38 19

20 39 Hemiacetal formation can occur within the same aldose or ketose sugar molecule wherein the function reacts with one of its own properly positioned groups (Fig.7) 40 20

21 半縮醛 ( 乙醛和醇化合反應的生成物 ). 41 C1 碳 anomeric carbon atom 42 21

22 如何證明 D-glucose 開鏈式結構形式不存在 (1) 開鏈式 D-glucose 具 -CHO 基但無 -CHO 基的 Schiff 反應加成反應也不易被 (2) 應以其他結構形式存在 43 (3) 環狀式使第一碳原子亦成為碳原子異構物 (anomer) or 異構物 (optical isomer) -form -form ( 醛醣與酮醣相同 ) 44 22

23 3. 構形式 (conformation form) 結構化學之進展非 Haworth formula 之六元環 : 形 (chair form) 形 (boat form) 五元環 : 形 (envelope) 形 (twist) 45 C-4 Bulky groups, CH2OH; OH C

24 4 C1 C-4 is raised slightly the plane C-1 is positioned slightly the plane 47 24

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投影片 1 第 5 章碳水化合物 Carbohydrates 碳水化合物平均每公克可以產生 4 大卡的能量, 它以血糖的形式隨時提供燃料給所有細胞, 以肝醣的形式儲存在肝臟和肌肉 1 圖 5-1 碳水化合物的食物來源註 :1 杯 =240 毫升 1 盎司 =30 公克 2 簡單醣