【作者】 徐娟；

【导师】 胡秋辉；

【作者基本信息】 南京农业大学 ， 食品科学， 2003， 硕士

【摘要】 采用硒和硒生物制剂，叶面喷施茶树制备富硒茶叶，研究硒对早春优质绿茶产量和品质影响，研究富硒茶叶的抗氧化和抗肝癌作用。为富硒茶叶的生物功能效应和从富硒茶叶中寻找有效的抗突变和预防肿瘤的成分提供新的理论依据，结果表明： 早春茶树叶面喷施含硒生物制剂，显著促进茶树提前发芽，明前优质高档茶叶产量提高2倍以上。茶汤的感官品质甜味、香气显著提高，苦味、涩味显著下降。硒提高茶叶茶多酚、氨基酸和维生素C的含量，表明硒能显著提高早春高档茶叶产量和品质，硒酸盐和亚硒酸盐无显著差异。 叶面喷施亚硒酸钠和含亚硒酸钠的生物肥，显著提高夏秋茶茶汤的香气和甜度，显著降低涩味和苦味。夏秋茶维生素C含量显著提高。富硒茶叶在贮藏过程中维生素C的损失显著低于普通茶叶。表明硒能显著提高夏秋茶的感官品质和化学品质，并且显著提高秋茶的保鲜品质。 硒能显著提高夏茶的抗氧化作用，在200mg L^-1和100 mg L^-1两种浓度下，富硒茶叶抑制亚油酸氧化和猪油油脂氧化作用显著高于普通茶叶，茶叶含硒量提高，抗氧化作用显著增强。 硒能显著提高春茶的抗氧化作用，富硒茶叶清除自由基的活性比普通茶叶显著增强，亚硒酸钠肥料和硒酸盐肥料差异显著。富硒茶叶抑制亚油酸氧化作用比普通茶叶显著增强。硒提高了商品茶叶自身的抗氧化作用，对提高绿茶保鲜品质具有重要意义。 硒组分与茶叶组分的协同抗氧化作用表明：富硒茶叶的抗氧化作用显著高于普通茶叶+硒酸盐，证明富硒茶叶中硒的化学形态不同于无机盐，硒与茶叶组分结合后表现出了强的抗氧化活性。 富硒茶和亚硒酸钠显著提高荷瘤小鼠血液和肝脏含硒量，提高小鼠血液和肝脏GSH-Px酶的活性，但对SOD酶的活性没有显著的影响。表明荷瘤小鼠组织对富硒茶和亚硒酸钠两种化学形态的硒的硒滞留能力较强。在硒摄入量1.0μg kg^-1，两种富硒茶的抑瘤率分别为49.43％和53.77％，普通茶叶为41.95％，亚硒酸钠为36.33％。在硒摄入量提高到2μg kg^-1时，两种富硒茶叶的抑瘤率分别为55.60％和61.79％。在等硒 硒对绿茶产量和品质的效应及富硒绿茶的抗氧化和抗肝癌作用 摄入量时富硒茶叶的抗癌活性显著高于普通茶叶和亚硒酸盐，表明单独的硒盐和硒盐 添加茶叶的抗癌活性都低于富硒茶叶，富硒茶叶中硒的化学形态与普通茶叶和亚硒酸 盐的差异性。富硒茶叶的高抗癌活性为肿瘤的化学防治提供重要的途径。更多还原

【Abstract】 Se-enriched tea leaves were processed by foliar applications of selenium and fertilizer of selenium. The influence of selenium on the yield and quality of green tea leaves harvested in different tea-producing season, the enhancement of selenium on antioxidant activity and the effects of Se-enriched tealeaves on liver cancer were determined. The results were shown as follows:Numbers of sprouts and the yield were significantly increased by application of selenium. The sweetness and aroma of green tea leaves were also significantly enhanced and bitterness were significantly decreased by application of selenium. However, no significant differences were found in sweetness, bitterness and aroma between tea leaves fertilized with selenite and selenate. Se concentration was significantly increased by selenium fertilization and tea enriched by sodium selenate had significantly higher selenium content than that sodium selenite. Total amino acid and vitamin C contents were significantly enhanced by application of selenium. Furthermore, the change of vitamin C in green tea sprayed with selenium during storage period was more stable compared with regular tea. Tea polyphenols contents were significantly decreased by fertilization of selenium. The marked difference of tea polyphenols was also found between application of selenite and selenate.The sweetness and aroma of green tea extracts were significantly increased and the astringent taste and bitterness were greatly reduced by spraying selenium during summer tea-producing season. Significant differences in astringent taste, bitterness and sweetness ofgreen tea extracts were found between sodium selenium and organically bound selenium. The total amino acid and vitamin C content of green tea were significantly increased and the ratio of polyphenols and amino acid of green tea were significantly decreased by spraying selenium. The vitamin C content of green tea during storage period was more stable with an increase of selenium content of green tea. No significant difference was obtained between sodium selenium and organically bound selenium. These results demonstrated that sensory and chemical qualities of green tea were improved by selenium.Se-enriched tea harvested in summer exhibited higher lipid inhibition activity in Linoleic acid system and Lard oxidation system. The antioxidant activity was dose-dependently correlated to selenium content in various kind of tea.In vitro antioxidant activity of Se-enriched tea produced in early spring was also enhanced by selenium application. Tea sprayed with selenite fertilizer provided significantly higher radical scavenging activity than that with selenate fertilizer. Inhibition acitivty against lipid oxidation was also significantly increased by selenium fertilizer.Results from DPPH and linoleic acid system method showed that antioxidant activities of Se-enriched tea were significantly higher than those of regular tea, selenide alone and regular tea in addition of selenide. Selenide exhibited weaker radical scavenging activity against DPPH and in linoleic acid system it showed a pro-oxidant activity of accelerating lipid oxidation. There were also significant differences between the antioxidant activities of Se-enriched tea fertilized by selenite and selenate. These results indicated difference in the chemical form of selenium in teas. This also suggested that a possible synergistic antioxidative effect existing between seleno-components and tea components in tea.Selenium contents in the blood and liver of tumor-bearing mice were significantly increased by injection of Se-enriched tea extracts and selenite in a dose-dependent manner. GSH-PX activities in mice liver and blood were also significantly enhanced. However, no marked differences were observed on the SOD activity. These results indicated that selenium in the chemical form of Se-enriched tea and selenite is easier to accumulate in mice tissue.Se-enriched tea exhibited stronger inhibition activity against hepatocarcinoma transpla -nttation tumor更多还原