| Water lily, a herbage of genus Nymphaea, family Nymphaeaceae, is a precious perennial aquatic flower plant, which is divided into two ecological groups, namely tropical water lily and hardy water lily. Because of its bright color, graceful posture and intense and long-lasting fragrance, it is deeply loved by people. The water lily from Beijing Botanical Garden was taken as material, using solid-phase micro-extraction chromatograph-mass spectrometer-computer to analyze volatile compounds, using diode array detector (HPLC-DAD) and HPLC electrospray ionization multi-stage mass spectrometry (HPLC-ESI-MSn) to analyze flavonoids in the tea, using 1,1-Diphenyl-2-picrylhydrazyl radical 2,2-Diphenyl-1-(2,4,6-trinitrophenyl) hydrazyl (DPPH),2,2’-Azinobis-(3-ethylbenzthiazoline-6-sulphonate)(ABTS),folin-phenol and ferric reducing antioxidant potential assay to analyze antioxidant activity in the tea.The research results were as follows:1. We separated the flower into three parts:pistil, stamen and petal, which was to analyze volatile compounds. We found that stamen releases the most volatile compounds, followed by petal and pistil. Stamen is the absolute domination in the release of volatile compounds, which is up to 70% to 90% in the whole flower. In addition, tropical water lily releases more volatile compounds than hardy water lily.2. We analyzed 117 kinds of volatiles in the stamen of 56 water lily cultivars, which consist of esters, alcohols, aldehydes, ketones, olefins and alkanes. In these compounds, the kinds and contents of olefins and alkanes are the most, followed by aldehydes and ketones. We detected 79 kinds of volatile compounds in tropical water lily, while in hardy water lily are 71. In 117 kinds of volatile compounds, there are 31 kinds of aroma components. In hardy water lily, most of the aroma components is alcohols including lilac alcohol, nerolidol and 3,7,11,15-tetramethyl,1,6,10,14-hedecatetraen-3-ol. While in tropical water lily, most of the aroma components is eater and aldehydes, including benzoic acid, ethyl ester,2-pentadecanone,3-(1,5-dimethyl-4-hexenyl)-6-methylene-cyclohexene and acetic acid, phenylmethyl ester.3. Hierarchical cluster and discriminant analysis were used to analyze the detected 117 kinds of volatile compounds, which divide water lily cultivars into three clusters:Culster A, Cluster B and Cluster C. Cluster A consisting of 22 hardy water lily cultivars is with the scent of rose and lilac. Cluster B, which is made up of 14 hardy water lily cultivars, is with the scent of lilac and fat. Cluster C which consists of 21 tropical water lily cultivars, is with the scent of matrimony.4. HPLC-DAD and HPLC-ESI (+/-)-MS2 were used to analyze the tea, which found 16 kinds of flavonoids. In the tea of water lily, there are 29 kinds of volatile compounds, nine of which were aroma compounds. The nine compounds are the main aroma compounds in the tea. Analyzing them, we concluded the aroma type of the tea, which are the scent of flower and fruit, the scent of aroma, the scent of flower with fat, the scent of lilac, the scent of spic, wood, citrus, camphor and mild cloves. Folin phenol, DPPH, ABTS and FRAP were used to analyze the antioxidant activity of the tea, which found there is a big difference between cultivars. And 3 kinds of suitable cultivars of the tea is elected: ’Conqueror’and’Virginia’as hardy water lily and’Subra’as tropical water lily. The content of flavonoid in the three tea of water lily is high, which is over 3mg·g-1. The former two cultivars are the scent of lilac, while the latter is the scent of flower and fruit. The three kinds of tea are full of aroma and are of high antioxidant activity. |
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