ANALYSIS OF CROCETIN DERIVATIVES FROM GARDENIA (GARDENIA JASMINOIDES ELLIS) FRUITS

From a point of view of quality evaluation of natural food color, the yellow pigments were isolated from the full matured fruits of Gardenia (Gardenia jasminoides Ellis) and identified mainly by LC-MS and H-1-NMR. In addition, the changes in the content and composition of crocetin derivatives in fruits were examined at the seven stages from anthesis to full maturity in order to obtain the information regarding to the biosynthetic pathway of crocin. The results obtained could be summarized as follows: (1) The full matured gardenia fruits contained seven yellow pigments which were crocetin derivatives. The structures and composition [%] were as given below. trans-crocetin-digentiobioside (crocin) [71.6%], trans-cocetin-monogentiobioside-monoglucoside ester [5.8%], trans-crocetin-monogentiobioside ester [2.0%], cis-crocetin-monogentiobioside ester [4.2%], trans-crocetin-diglucoside ester [10.8%], trans-crocetin-monoglucoside ester [3.0%], cis-crocetin-monoglucoside ester [0.4%], (2) Gardenia fruits contained very small amounts of carotenoids at the enlargement stage but accumulated considerably crocetin derivatives in the process of maturity. The contents of total crocetin derivatives in full matured fruits went up to approximately 4.5 mg/g (dry weight). The time course of changes in composition of seven crocetin derivatives in the maturing stage suggested that gentiobiose ester of crocetin was biosynthesized stepwise by binding glucose to crocetin glucose ester.