SUMMARY About 90% of the hydrogen sulfide (H2S) produced by heated chicken muscle comes from muscle protein. To identify specific H2S precursors, the identity, quantity, and H2Sproducing capability of sulfur compounds in chicken muscle were investigated. The only sulfur compounds found in muscle nonprotein were methionine, taurine, and glutathione. Of these, only glutathione produced H2S. Therefore the principal H2S precursor in chicken muscle nonprotein is sulfur, occurring as eystine and/or cysteine in the tripeptide glutathione. Since the only sulfur compounds reported in chicken muscle protein are methionine, cystine, and/or cysteine, and since methionine does not produce H2S, the sulfur in the H2S produced by muscle protein must also come from cystine and/or cysteine. Glutathione gives off H2S about 180 times as fast as does chicken muscle protein, but, because there is approximately 1 to 2 thousand times as much protein as glutathione in muscle, protein is the principal H2S precursor. Since cystine plus cysteine, sulfur in protein and in glutathione is the only H2S precursor, the rate of H2S evolution from heated chicken muscle can be approximately predicted from its cystine content.

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SUMMARY: Fat of raw poultry, separated from solid tissue and washed with water at temperatures not exceeding 40°C does not contain cooked poultry aroma and does not develop it when heated. Hence, cooked poultry aroma cannot be derived from the fat alone. Washed and filtered fat from cooked poultry contains characteristic cooked poultry aroma dissolved in it. The aroma of this fat is caused by compounds which dissolve in it during cooking and which apparently stem from nonfat or lean portions of the meat. The ability of fat to dissolve or acquire substances during cooking was demonstrated by showing that fat of cooked poultry contains more sulfur than does fat of raw poultry. Less than 2% of this sulfur build‐up occurs as hydrogen sulfide. The magnitude of the sulfur build‐up was 8 to 14 times greater in the fat of roasted poultry than it was in the fat of simmered chicken. Authentic amino acids in contact with poultry fat at a typical roasting temperature readily underwent Strecker type degradation. Furthermore, aroma components representing typical amino acid degradation products were found in fat from roasted turkey. These analytical results indicate protein, amino acids and probably also sugars and other water soluble components are invoved in aroma formation. Hence fat contributes to cooked poultry aroma indirectly and passively through its ability to dissolve and retain aroma components formed during cooking. Consequently, the characteristic cooked poultry aroma in fat of cooked poultry is not derived from the fat itself but comes from and is thus dependent on the “lean”.