點解白菜經過發酵(變成泡菜)會縮水?

係因為鹽，鹽令菜脫水，不只係菜，肉都會，你不防留意下，當你用鹽醃肉或魚，又或其實食材，你會約少於半小時，就見到底部會有好多水，但菜既水份比肉少，所以菜就比較明縮少左。

2009-11-21 10:29:59 補充：
但菜既水份比肉少..........更正係菜較多水份，當佢冇左大量水份時，就會縮得好細。

will yeast absorb water during anaerbic respiration?
我唔係好明你問咩 ?重之同發酵冇關。

Water diffuse from the cells, Osmosis occurred.
anaerobic respiration of yeast will produce carbon dioxide + ethanol(alcohol) + energy, these come from glucose/carbohydrate/starch.
also when more ethanlo produced, the concentration of the solution bathing the cells becomes higher, so water potential of this solution becomes lower. therefore more water will then diffuse out by osmosis.
So anaerobic respiration of yeast do not absorb water.

2009-11-29 22:49:32 補充：
點解白菜經過發酵(變成泡菜)會縮水?

for this question, salt is the reason, since salt will move into vegetable and water diffuse out of the cells, osmosis, or high concentration of salt solution outside the cells will diffuse into the cells. equilibrium

因為鹽!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

During fermentation , the water in the cell of the vegatable will move out due to the osmosis(water move through the cell wall) & because of fermentation water is required to form carbon dioxide , alcohol & acids . The source of oxygen can only from water since fermentation taking place in anaerobic respiration . As water moves out the cell of vegatable , it will get smaller .

2009-11-27 18:20:38 補充：
I am sure some microorganism will absorb water to provide oxygen to form CO2 , ROH or RCOOH ..