??

I would imagine the extent to which the are destroyed and the amount depends on the method used to cook (i.e. grilling, roasting and frying would destroy more than say.. light steaming). Fresh is best.

I could be wrong though and arugula would probably give a better answer.



My website: The Coconut Chronicles

Perhaps they are not destroyed, but rendered unusable by the body, and as such they become a waste product that the body needs to deal with. This is the reason why people who eat cooked foods have a huge rise in white blood cells in their bloodstream after eating a cooked meal.

Yes, some damage takes place when they are cooked. The temperature reached is a better indicator of the extent of damage rather than the duration of cooking, i.e. 1 hour at 100C is not as bad as 5 minutes at 400C. Deep frying is The Worst.

Gory details from Dworschak E., Nonenzyme browning and its effect on protein nutrition. Crit Rev Food Sci Nutr. 1980;13(1):1-40. PMID: 6996923

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By the heat treatment, the sulphur-containing amino acids of proteins (cystine, methionine) are damaged primarily because of oxidation, but the decrease in the amount of threonine, serine, tryptophan, and lysine is observable too.

According to the formation of enzyme resistant cross-links, the in vitro and in vivo digestibility of protein decreases after the heat threatment and the communication with oxidized fats.

Besides the amino acids mentioned, the possibility of enzymatic break-off of leucine and isoleucine is reduced too. In the course of the heating of proteins the occurance of racemization has to be considered too (formation of alloisoleucine).

The basic mechanism of the reaction between sugars and simple amino acids is already essentially explained: amino-acids break off after the formation glycosilamines and Amadori products but they are linked irreversibly to some, partly unsaturated decomposition products of sugars, types of 6 and 3 carbon atoms.

The decrease in the biological usability of amino acids starts already with the Amadori products. The reactivity of the single amino acids depends on the number of carbon atoms, on the basicity, and on the polarity of the amino acid molecule. The especially highly reactive amino acids of proteins are

(1) lysine (because of its 6-HN2 group),
(2) other types of basic amino acids, and
(3) trypotphan (because of the lability of the indole ring), methionine, cystine and threonine. In the Maillard reaction of tryptophan the --NH--group of the indole ring is involved too.