---
# System prepended metadata

title: Biomolecules Tests
tags: [Y2, Science]

---

# Benedict's Test for Reducing Sugars
- Test for presence of reducing sugars with **Benedict's test**
- Procedure:
	- If solid, grind food sample with distilled water with mortar and pestle before filtering the mixture to obtain filtrate
	- Add **equal volume** of Benedict's reagent to 2cm$^2$ of the filtrate or liquid
	- **Shake** the mixture
	- Heat a beaker of water until it **boils**.
	- Boil it in the boiling water bath for **2 minutes**
	- Orange/Brick-red precipitate formed if reducing sugars found

# Iodine Test for Starch
- Test for the presence of starch
- Procedure:
	- add 2-3 drops of iodine solution to the food sample
	- Blue-black if starch present, orange-brown if starch not present

# Ethanol Emulsion Test
- Tests for the presence of lipids (fats)
- Procedure:
	- Add 2cm$^3$ of **ethanol** to **liquid** food sample in a test tube
	- **Shake** thoroughly
	- Add 2cm$^3$ of distilled water and shake
	- Cloudy white emulsion if fat is present

# Biuret Test for Proteins
- Test for the presence of **peptide bonds (cannot test for amino acids!!!!)**
- Procedure:
	- Add 2cm$^3$ of sodium hydroxide solution ($\ce{NaOH}$) to food sample and shake thoroughly.
	- Add 1% copper(II) sulfate solution ($\ce{CuSO4}$) drop by drop, shaking after every drop
	- If remain blue, no protein, if turn violet, got protein

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