| Tangerine peel and orange peel belong to Rutaceae citrus, and were the same species of orange peel, Citrus reticulate “Chachi” mainly produced in Xinhui county of Guangdong Province in China, which is regarded as a genuine tangerine peel. The main components of the tangerine peel is volatile composition and flavonoid composition and its volatile oil. Tangerine peel are easily affected by production area, climate and ecological environment, these factors make great differences in the composition for the different areas and different harvest and different storage life of orange peel, tangerine peel and its volatile oil, which directly lead to difference of the quality and efficacy. Tangerine peel has the statements of “the longer the better”, because if the reserve time increasing long, the medical effect and aroma of tangerine peel is better. What is show “the longer the better”, what is the main quality differences.Therefore, we have studied the CRC from different years and the volatile oil of tangerine peel from different areas and orange peel from different areas and different harvest times, we have systematically studied its active ingredient and flavor changes, and the systematic described and analyzed the mechanism of change for the parlance, “the older the better”. The main research contents and results were as follows:(1) The variations of chemical components analysis for the volatile oil of tangerine peel from different areas. The chromatographic fingerprints of volatile oil of tangerine peel were established by GC-MS, the PCA and semblance analysis methods were applied to find the similarity and difference among 22 kinds of volatile oil of tangerine peel. The results showed that the similarities of 22 kinds of volatile oil of tangerine peel were between 0.886~1, the samples from Sihui, Szechwan, Nanfeng, Xinhui, Guiling got a good distinction, and the samples from Yunfu, Wuzhou and Qingyuan got together in cluster, the L-?-pinene, ?-farnesene, ?-pinene of congenerous peaks and Germacrene of trace compositions in the fingerprints were confirmed as the distinguished components by PCA. By comparing its contents of flavonoids, found that the content of flavonoids is the highest levels of Guilin and Yunfu, and low content of Qingyuan and Wuzhou.(2) The variations of chemical components analysis for the orange peel from different areas and different harvest time. Their volatile components and flavonoids determined by GC-MS fingerprints technology combined with HPLC technology, and combined with the two aspects to evaluate the quality of orange peel from different areas and different harvest time. The result showed that the orange peel from Guilin in Guangxi province have the best aroma quality in September, its contents of three flavones reached to 1.25 mg/g and of the best quality in September. In October, the similarity values to the reference chromatograms of the orange peel from Shaoguang in Guangdong province was 0.997 and have the best aroma quality, its contents of three flavones reached to 1.33 mg/g and of the best quality. In November and December, the orange peel of Sihui have the best aroma quality, its contents of three flavones reached to 6.56 mg/g and of the best quality. For the orange peel of Guilin in Guangxi province, and the orange peel of Guilin in November have the best aroma quality, where contents of three flavones reached to 1.45 mg/g and of the best quality. For the orange peel of Jiangxi province, honey orange in November have the best aroma quality, its contents of three flavones reached to 8.44 mg/g and of the best quality.(3) The mechanism of change and material basis analysis for “the longer the more mellow” in CRC. We used GC-MS fingerprints technology combined with principal component analysis and GC-O technology delve into characteristic aroma components and synthetic pathways of CRC from different years. The results show that mentha-1,5,8-triene, dihydrocarvone, terpinen-4-ol have important contribution to the “the longer the more mellow”of CRC. The mentha-1, 5, 8-triene, dihydrocarvone, terpinen-4-ol present minty, wild chrysanthemum, old wood aroma respectively. The characteristic aroma compounds mainly converted by three metabolic pathways of D- limonene, wherein D- limonene is characteristic aroma precursors, terpineol, D-carvone, carveol, carvacrol, thymol and 4-isopropyl-3-methyl-phenol as an intermediate characteristic aroma compounds.(4) The mechanism of change and material basis analysis for the flavonoids of “the older the better”. The content of flavonoids in CRC from different years was determined and analyzed by HPLC technology. The results show that the contents of nobiletin and tangeretin present increasing trend with the duration of storage time, and the content of 7-methoxyflavone show fluctuating trend throughout the storage time in addition to tangeretin peel of 2013 years. Using HPLC-MS technology and contrast the HPLC bar of flavonoids, Eight flavonoids were identified in methanol extract of tangeretin peel, which were ferulic acid, citropten, 5,6,7,3',4'-pentamethoxyflavone, lsosinensetin, tetramethylscutellarin, 3,5,6,7,3',4'-hexamethoxyflavone, 5,6,7,8,3',4'-hexamethoxyflavone, tetramethoxyflavone, and synthesize the change of flavonoids contents of CRC, inferred that tetramethyl scutellarin, nobiletin and tangeretin have important contribution to the “the older the better” in flavonoids, three characteristics of flavonoids compounds were converted by 7-methoxyflavone, pentamethoxyflavone and citropten. |
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