炭水化物のデンプン-ヨウ素テスト

ヨウ素液を使って食品中のデンプンを検出する

Qualitative Analysis Beginner (Middle School) 30 分 ~$5.00

目的

ヨウ素テストで様々な食品中のデンプンを同定し、青黒色の錯体が形成される分子的メカニズムを理解する。

背景

The starch-iodine test is one of the most visually striking qualitative tests in chemistry. Iodine (I₂) forms a deep blue-black complex with amylose, the helical component of starch. The iodine molecules slip inside the amylose helix, creating a charge-transfer complex that absorbs light strongly. This test does not work with simple sugars (glucose, sucrose) or with amylopectin alone, making it specific for amylose-containing starch.

安全上の警告

  • Iodine solution stains skin and clothing
  • Do not taste any samples after adding iodine
  • Handle knife carefully when cutting food samples

必要なPPE

goggles lab_coat

材料

  • Iodine solution (Lugol's) (10 mL)
    I₂/KI solution
  • Starch solution (1%) (10 mL)
    Positive control
  • Glucose solution (1%) (10 mL)
    Negative control
  • Food samples (Various)
    Potato, bread, rice, apple, etc.
  • Distilled water (50 mL)

器具

Spot plate or small dishes Dropper pipettes Knife for cutting food samples White paper background

手順

1

Place small amounts of each food sample and control solutions in separate wells of the spot plate.

5 分
2

Add 2–3 drops of Lugol's iodine solution to the starch solution (positive control). Observe the blue-black color.

3 分
3

Add 2–3 drops to the glucose solution (negative control). Observe that the color remains amber/brown.

3 分
4

Add 2–3 drops of iodine to each food sample. Record the color change observed.

10 分
5

Classify each sample as starch-positive (blue-black) or starch-negative (amber/brown). Record in a data table.

9 分

予想される結果

Potato, bread, and rice should test strongly positive (deep blue-black). Apple and pure sugar solutions should remain amber/brown. The intensity of the blue color correlates with starch content.

後片付け

Dispose of iodine-treated samples in general waste. Rinse spot plates and pipettes with water.

詳細

カテゴリ
Qualitative Analysis
難易度
Beginner (Middle School)
所要時間
30 分
推定費用
$5.00
ステップ数
5
材料
5

その他の実験

pH指示薬の虹 45 min ハロゲンのバイルシュタイン試験 25 min 未知物質同定チャレンジ 75 min 植物色素のクロマトグラフィー 60 min 沈殿による陽イオンの同定 90 min 炎発光分光分析 60 min 石けん液による硬水試験 40 min 金属イオンのホウ砂ビーズ試験 45 min 陰イオン同定試験 60 min

Frequently Asked Questions

What is the objective of 炭水化物のデンプン-ヨウ素テスト?
ヨウ素テストで様々な食品中のデンプンを同定し、青黒色の錯体が形成される分子的メカニズムを理解する。
How difficult is 炭水化物のデンプン-ヨウ素テスト?
This experiment is rated as Beginner (Middle School). It takes approximately 30 minutes to complete.
What safety precautions are needed for 炭水化物のデンプン-ヨウ素テスト?
Key safety precautions include: Iodine solution stains skin and clothing; Do not taste any samples after adding iodine; Handle knife carefully when cutting food samples.
What materials are needed for 炭水化物のデンプン-ヨウ素テスト?
The main materials required are: Iodine solution (Lugol's), Starch solution (1%), Glucose solution (1%), Food samples, Distilled water.
What results should I expect from 炭水化物のデンプン-ヨウ素テスト?
Potato, bread, and rice should test strongly positive (deep blue-black). Apple and pure sugar solutions should remain amber/brown. The intensity of the blue color correlates with starch content.