Jean-claude wrote:

 >WHt doe nutrient retention factor means? WHat survive the cooking ? or what
 >is lost ?

According to the documentation of the USDA Nutrient Database, nutrient
retention factor is what survives the cooking, expressed in percent. I
think the following table is quite interesting:
http://www.nal.usda.gov/fnic/foodcomp/Data/retn4/retn4_tbl.pdf
It is widely used, but, it doesn't tell anything about the bioavailability
of nutrients after cooking.

 >> I don't know the value for beef or any other ruminant. I wish I knew.
 >> There's nothing in the USDA Nutrient Database, as you may have noticed
 >> yourself. However I've read [1] that the human adrenal gland contains at
 >> least 1
40 umol vitamin C per 100 g. I think that's around 25 mg per 100
 >> g. Sounds little, because according to the same source, and as you surely
 >> know, the gland in question is one the richest sources of vitamin C in
 >> the human body.
 >and adrenals are so small just few grams  each , that sounds stange .

I guess I formulated myself badly. I wasn't talking about amount, I was
talkning about mass-density. You say that adrenals only weigh a few grams.
If that's true, and the vitamin C density is at least 25 mg per 100 g, then
there's between 250 and maybe 750 ug vitamin C in adrenals, at least. Not
very great amount. Correct me if I'm wrong.

 >>(Same goes for pituitary glands and lens of the eye.)
 >also rich in vit c?

Yes, according to these pages:
http://www.exrx.net/Nutrition/Antioxidants/VitaminC.html
http://ceiba.cc.ntu.edu.tw/nutrchem/vitc
.html

/Fredrik