| The wines made in China and the grape (Vitis vinifera L. cv. Cabernet Sauvignon) berry were used as material, and the analytical system of flavan-3-ols and proanthocyanidins were established. Five kinds of flavan-ols, including (+)-catechin(CAT/C), (-)-epigallocatechin(EGC), (-)-epigallocatechin gallate(EGCG), (-)-epicatechin(EC), and (-)-epicatechin gallate(ECG), were separated and determined firstly through a chromatographic column of 5 μm LiChrospher 100RP-18e (250×4.0mm I.D., Merck) by the mobile phase gradient elution of glacial acetic acid solution, and as we known, it is the first time to determine EGC, and EGCG in the wines. The analytical system of proanthocyanidins in the wines was also establishment based on the published report. The concentration, the mean degree and the composition of proanthocyanidins has been studied using (1)fractionation and purification on TSK HW-50(F)(Tosoh, Japan) by different solvents, (2)fractionation followed by acid-catalyzed degradation in the presence of phloroglucinol.The results of 12 type of wines made in China by different manufacturer indicated that the concentration of flavan-3-ols and proanthocyanidins in the wines was depended on the type, material, and the wine-making technology. CAT and EC is the mostly abundant monomeric flavan-3-ols in red wines, and the mean degree polymerization (mDP), composition of proanthocyanidins in the wines were diversified. CAT and EC was the mostly terminal units of proanthocyanidins, and the EC was the mostly extension units.During the fermentation of Cabernet Sauvignon and Chardonnay, the flavan-3-ols and proanthocyanidins transferred rapidly from solid parts of the grape cluster into the wine. The concentration of 5 kinds of flavan-3-ols, especially CAT and EC, were all increased. CAT and EC, as one group, get the highest at 5th day of the fermentation, As the other group, ECG, EGC, EGCG get the highest at the first day of the fermentation. During the aging in the oak barrel, the concentration of CAT, EC, and ECG were increased, and EGC was decreased dramatically. The concentration and the mean degree polymerization (mDP) of proanthocyanidins decreased, whereas the composition of proanthocyanidin changed slightly.The changes on the concentration and composition of flavan-3-ols and proanthocyanidins in different tissue were studied during the development of grape berry by using 7-years old Cabernet Sauvignon (Vitis vinifera L.) and Chardonnay {Vitis vinifera L.) berry. Flavan-3-ols and proanthocyanidins were mainly accumulated in the skin and seeds during the grape berry development. During the grape berry development of Cabernet Sauvignon, flavan-3-ols in the skin got highest at the 20 days after full bloom, and then declined. Proanthocyanidins were reached highest at the 20 days and 50~60 days after full bloom, and then decreased during the ripening. In the seeds, flavan-3-olsmonomers, proanthocyanidins increased up to veraison (70 days after full bloom), 50 days after bloom, respectively, but declined thereafter. The changes of flavan-3-ols and proanthocyanidins in the Chardonnay were likely to the Cabernet Sauvignon.Used the grape berry of Cabernet Sauvignon and Chardonnay, the expression of gene involved the proanthocyanidins biosynthesis, PAL, CHS, F3H, DFR, and LDOX in skin, flesh, and seeds during grape berry development were examined by RT-PCR. All of the genes were expressed in the skin, flesh and seed, but the pattern of expression in different tissues tested was different. The mRNA level encoding PAL, CHS, F3H, DFR, and LDOX were high at 20 days after full bloom in all tissues, and then decreased except in the skin of Cabernet Sauvignon.The inducement of SA on the genes involved the proanthocyanidins biosynthesis were detected by using in vivo preincubation of the grape berry tissue and low pressure penetration of grape berry in the SA-contanied medium. The results showed that SA could induce the expression of PAL, CHS, F3H, DFR, and LDOX gene, and the mRNA accumulation reached maximum at 30 min, 16-24 h respectively. To... |
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