[Thanksforanswers]

Quick introduction/context:
Proteins are broken down in the small intestine, however, some part of the amino acids resist digestibility and travel down to the large intestine (like resistant starch). The percentage of consumed amino acids digested in the small intestine is given by the 'ileal digestibility' (FrieslandCampina Institute). Methionine, cysteine, homecysteine and taurine are the 4 common sulfur-containing amino acids. Only two are normally present in proteins, namely methionine and cysteine (Ronald Steriti, 2012). Most utilizable sulfur comes with sulfur amino acids in proteins of animal and plant origin. Much smaller amounts are consumed as sulphate. Some sulfur compounds, such as the potentially toxic hydrogen sulfide, are produced when bacteria in the distal intestine (colon) act on nonabsorbed amino acids (Kohlmeier, 2015). The 'non-absorbed amino acids' in the colon (the part of the amino acids which is not broken down in the ileum) are metabolized in the colon by sulphur-reducing bacteria to produce hydrogen-sulphide (H2S) (Fleet, 1993). H2S is associated with the 'rotten eggs smell' (Fleet, 1993). Moreover, H2S is associated with pro-inflammatory activity in the gut in ulcerative colitis and Crohn's disease (whereas other microbes in the gut (probiotics) act on resistant starch to produce butyrate which acts anti-inflammatory for the gut lining -> so you want fermentation of resistant carbs in your gut, but not fermentation of undigested protein?).

According to https://tools.myfooddata.com/nutrition-comparison.php:
- a 50mg-egg contains 190mg methionine and 136mg cystine; and
- a portion of 200mg raw chicken breast contains 1.170mg methionine and 472mg cystine.

1. How can it be that consuming an egg can produce more of the 'rotten egg smell' than consuming 200mg of chicken breast, given their methionine and cystine contents?
2. How can it be that these smells are produced within 1-2 hours, while the SRB produce H2S in the colon? The protein cannot be in the colon already.