58(P25) トウガラシ色素のエステル化反応と安定性について(ポスター発表の部)

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Capsanthin esters were separated from paprika (Capsicum annuum) oleoresin, and their structures were determined without saponification.3) The major diesterified and monoesterified capsanthins were identified as 3,3'-lauroylmyristoylcapsanthin (LM-CP) and 3'-myristoylcapsanthin (M-CP), respectively. HPLC, UV and 2D-densitometoric analyses indicated that 3'-O-esterified capsanthins exist in a much larger quantity than the 3-O-esterifed ones. The time-course accumulation of capsanthins was then observed in several cultivar of C. annuum fruits. Esterified capsanthins appeared almost simultaneously with the appearance of capsanthin itself and the amount of the 3'-O-esterified one was larger than that of the 3-O-esterified one during all stage of ripening (Fig. 3). These results suggested that esterification at the cyclohexene ring is the rate-determining step in the biosynthesis of esterified capsanthin and that the 3'-hydroxyl group on the cyclopentane ring is esterified much faster than the 3-hydroxyl group on the cyclohexene ring (Fig. 2). Several reports have suggested that esterified capsanthins were more stable than capsanthin itself.2) To verify this fact, we monitored the degradation of capsanthin, LM-CP and M-CP in paprika powder and the extract during storage under illumination. The amount of capsanthin was reduced time-dependently; however, the amounts of the esterified ones increased in the early stage but, then decreased as fast as capsanthin (Fig. 4). The LC-MS results suggested that the increase in the early stage was ascribed to the isomerization of the naturally occurring Z-isomers. We next studied the stability of individual capsanthin and LM-CP in solutions. In the same solvent, the degradation curves for both compounds were quite similar. On the basis of these data, it was concluded that the stability of capsanthin and the esterified capsanthins do not significantly differ from each other.
天然有機化合物討論会の論文
1996-09-02

58(P25) トウガラシ色素のエステル化反応と安定性について(ポスター発表の部)

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