The Theory

• There is a simple concept to why the bitterness of bitter gourd is reduced after soaking it in salt solution and the answer is OSMOSIS. Osmosis is the concept in which water moves from a high water concentration to a low water concentration.
• The bitterness in bitter gourd is due to the high concentration of quinine in it.Quinine is an alkaloid compound that produces bitter taste.
• When the bitter gourd is soaked in salt solution the salt solution will draw out water from the the bitter gourd through osmosis.Together with the water, bitter alkaloid compound which is quinine will also be removed. (Lori Alden 2005; Wikipedia 2009)
  

THE THEORY @ EXPLANATION

(1)Can be consider as bitter gourd -Lower salt concentration (hypotonic)
(2)Can be consider as the salt solution -Higher salt concentration (hypertonic)

1. The bitter gourd have a lower concentration of dissolved salt as compared to the salt solution.
2. This means that the bitter gourd can be consider as hypotonic and the medium surrounding it which is the salt solution is hypertonic.
3. So the water will move due to osmosis from the hypotonic condition to the hypertonic condition, this is because it is trying to balance the concentration on both side.
4. Movement of water from the bitter gourd will also carry with it the bitter alkaloid compound thus reducing the bitterness of bitter gourd. (Lori Alden 2005; Wikipedia 2009)

* Soaking in salt solution can only reduce but not eliminate the bitterness in bitter gourd because only a certain percentage of water will be removed from the bitter gourd which means that only some of the bitter alkaloids compound will be carried out together with the water.