オレンジミートに関する研究-II

糖-アミノ酸系の加熱によつて生成する螢光性物質の存在

抄録

It has been reported in the preceeding paper, that there is a close relation between the orange coloration and the formation of fluorescent substances in canned skipjack meat.
In order to elucidate the cause of orange coloration, fluorophotoanalytical investi-gations were carried out.
Two dominant kinds of fluorescence were observed on the orange colored meat of canned skipjack; one had an excitation maximum at λ 290 nm and an emission maximum at λ 350 nm (I), the other at λ 333 nm and, λ 400 nm respectively (II). From their excitation and emission spectra and their intensities of fluorescence in different pH, (I) was ascribed to tryptophan, and (II) was ascribed to sugar-amino acid reaction products. On high alkalinity, however, an unidentified fluorescence presumably caused by pterine was observed. Nineteen amino acids were treacted individually with D-ribose in phosphate buffer at pH 6.4 and 121°C in an autoclave for 60 min, and the fluorescence characteristics of the resulting solutions were examined. Though many of them were more or less similar to (II) fluorophotometrically, those of the histidine-ribose and proline-ribose systems were almost identical with (II). All showed most intense fluorencence at pH 4.3. The deeper the brown-yellow of the sample, the more intense was the fluorescence.
The above data suggest that the orange coloration is caused by sugar-amino acid reactions in the can, and that histidine especially plays an important role in the coloration.