Nitrogen Compounds of Cabbage. Ii. Chromatographic Analysis of the Non‐protein Nitrogen

Nitrogen Compounds of Cabbage. I. The Relation of the Non‐protein to the Total Nitrogen With Special Reference to the Essential Amino Acids

“…Data in Table 5 were obtained in order to compare the recovery of arginine, threonine and lysine using electrodialysis, aqueous ethanol and hot water (100" C) extractions, and to determine the values for these 3 amino acids in the Danish strain of Copenhagen Market cabbage. Our interest in the use of aqueous ethanol and hot water as extractants of the soluble nitrogen constituents of vegetables came about as a result of our chromatographic studies (46) in which aqueous alcohol was used as the extractant. Arginine and lysine values were lower in the alcohol extracts analyzed by the chromatographic method than in the electrodialyzed cathode fraction analyzed by the microbiological procedure.…”

“…This same statement cannot be made for certain other amino compounds present in cabbage tissue in considerable amounts. Zacharius et al, in the second paper of this series (46), have identified and estimated an additional 11 amino compounds and postulated the presence of others which contribute to the total nitrogen of the tissue extract. A complete nitrogen balance can be obtained only after all of these compounds are quantitatively determined.…”

“…The pH changes that occur during electrodialysis are probably a result of the breakdown of this compound and of asparagine (46). Starting with an initial pH of 5.8 in the cabbage slurry the pH of the cathode reached 10.4 within 15 min and 12.0 within lyz hr.…”

“…In an alternate procedure non-protein nitrogen was also extracted with 70% aqueous ethanol by the method described in the second paper of this series (46).…”