Topics:
Animal Nutrition, Animal Refresher
Pigment Causing Brown Color in Silage
The brown colour of silage is due to:
- Chlorophyll
- Lactic acid
- Phaeophytin — Correct Answer
- Butyric acid
Explanation:
Correct Answer: Phaeophytin
The brown colour of silage is due to Phaeophytin — formed when the magnesium atom in the centre of the chlorophyll molecule is displaced by hydrogen ions (H⁺) under the acidic conditions of silage fermentation. This converts green chlorophyll to brown phaeophytin.
Colour Changes During Silage Fermentation
| Compound | Colour | Condition |
|---|---|---|
| Chlorophyll | Bright green | Fresh plant material |
| Phaeophytin | Brown/olive | Acid (H⁺ displaces Mg²⁺) → in silage |
| Chlorophyllide | Bright green | Enzyme action (chlorophyllase) |
| Pheophorbide | Brown | Further phaeophytin breakdown |
Summary: Pigment Behind Colour in Hay vs Silage
- Brown colour of Hay → Maillard-type reaction (sugar + lysine at high moisture).
- Brown colour of Silage → Phaeophytin (chlorophyll + H⁺ under acidic conditions).
- Both are important distinctions frequently tested in examinations.
Why Other Options Are Wrong
- Chlorophyll → the green pigment in fresh plants; converted TO phaeophytin, not responsible for brown colour.
- Lactic acid → the preserving acid in silage; it causes the low pH that drives phaeophytin formation but is not itself the brown pigment.
- Butyric acid → produced in bad-quality silage; responsible for foul odour, not brown colour.
📚 About this Topic — Animal Nutrition
This multiple choice question is from Animal Nutrition, Animal Refresher. It has 4 options with a detailed explanation of the correct answer. Practice more MCQs from Animal Nutrition to strengthen your preparation.
