单宁酶处理提高茶梗儿茶素含量及茶梗提取液生物活性

为综合利用茶叶加工副产物茶叶梗,试验设计利用固态发酵得到的单宁酶处理茶梗,比较不同处理条件下的茶梗提取液中儿茶素组成的差异及还原力、DPPH和OH自由基清除率、胰α-淀粉酶和胰脂肪酶抑制活性变化,探讨单宁酶处理提高茶梗提取物中儿茶素含量和生物活性可行性。研究发现：在50℃条件下,利用2 U/mL单宁酶溶液作用于茶梗粉末60 min,茶梗提取液中酯型儿茶素（EGCG、ECG、GCG）基本被水解生成非酯型儿茶素（EGC、EC、GC）和没食子酸（GA）,从而减少单宁-蛋白质聚合物和茶乳的形成量;此外,经单宁酶处理的茶梗提取液抗氧化活性与对照比较明显增强,表现为OH和DPPH自由基清除率IC50分别降低了74%和26%;酶解茶梗提取液质量浓度为5 000 mg/L时,胰α-淀粉酶和胰脂肪酶抑制率分别提高了89%和107%。研究结果表明单宁酶可高效水解茶梗提取液中酯型儿茶素,提高茶梗提取液的抗氧化活性以及体外抑制胰α-淀粉酶和胰脂肪酶活性。     

外源苯丙氨酸对茶树培养细胞儿茶素合成的影响

研究了在培养基中添加类黄酮生物合成前体苯丙氨酸后，对于茶树培养细胞表儿茶素等次生产物合成的影响，以外源物质饲中辅`在数等为基础，分析了茶树培养细胞对外源添加物吸收与利用的动态表现，以及外源苯丙氨酸饲喂所带来的产物经民水平变化。实验结果表明，当源饲喂1000μmol/L苯丙氨酸时，L－表儿茶素（L－EC）与D，L－儿茶素（D，。－C）的含量比对照增加了40％，由二种儿茶素和多各上儿茶素低聚体组成的乙酸乙酯萃取物的总量增长了66％。     

仁化白毛茶生化成分与成品白茶品质的相关性研究

为科学有效地选育出适制或兼制白茶的优良茶树品种,以广东省粤北仁化白毛茶群体中筛选的7个丹霞系列新品种(系)为材料,从生化成分差异性、加工前后生化成分的变化2个方面研究了主要生化成分与白茶感官品质间的相关性。结果表明:7个丹霞系列茶树品种(系)间主要生化成分存在种性差异,其白茶品质风格各具特色,品质皆优;加工后成品白茶中茶多酚和可溶性糖含量均显著减少,游离氨基酸含量极显著增加,总儿茶素、酯型和非酯型儿茶素含量均降低。偏相关性分析表明,酚氨比和糖咖比与白茶感官品质得分呈显著正相关,其中鲜叶酚氨比、成品白茶糖咖比对白茶感官品质的形成具有积极作用,并建立了白茶感官品质评价最优方程式。本研究结果为评价白茶感官品质提供了新的方法,也为白茶茶树品种的筛选提供了指导。     

不同覆盖物对茶籽播种萌发的影响分析

本试验采用金萱、中茶108和黄金芽三个茶树品种茶籽,播种时利用三种不同覆盖物处理进行覆盖,茶籽萌发后调查出苗率;结果表明:纯细沙和细沙与泥土混合物(1︰1)的两种覆盖物对茶籽萌发较好,萌发出苗率都在50%以上。说明茶籽直播过程中采用纯细沙和细沙与泥土混合物的两种覆盖物进行覆盖是可行的。     

重离子注入与电离辐射作用下小麦种胚内非按期DNA合成的比较

用放射性同位素￣３Ｈ－胸腺嘧啶核苷渗入法，研究Ｆｅ￣（１＋）注入与￣（６０）Ｃｏγ射线辐照条件下，小麦种子萌发早期种胚内ＤＮＡ的合成动态，以非按期ＤＮＡ合成为标志，比较重离子束与γ射线作用下ＤＮＡ损伤、修复程度的差异。同时采用扫描电镜Ｘ射线能谱分析法（ＳＣＥ－ＥＤＡＸ）对造成这种差异的机制进行了探讨研究。研究结果表明，γ射线辐照后，种胚内存在典型的非按期ＤＮＡ合成，但在重离子注入条件下，这一现象并未表现出来。因此重离子的作用过程和诱变机理与γ射线的作用有所不同。重离子对种子的诱变是一种间接的作用，因为ＳＣＥ－ＥＤＡＸ的结果证明离子注入种子的深度为１４μｍ，并未真正到达小麦种胚内部。     

不同品种乌龙茶种植后土壤肥力和茶叶品质的变化

本研究以毛蟹(C.sinensis cv.Maoxie)、本山(C.sinensis cv.Benshan)、梅占(C.sinensis cv.Meizhan)3个乌龙茶品种为研究对象,分析不施肥条件下茶树根部土壤养分随种植年限的变化,以及茶叶品质的变化。结果表明,不同茶树的根部土壤p H值均随茶树种植年限的增长而呈现下降趋势。不同茶树根部土壤的有机质及有效磷含量达到Ⅰ级肥力;0年取样的茶树土壤碱解氮含量为Ⅰ级肥力,不施肥种植1~2年后均为Ⅱ级肥力;土壤速效钾含量在茶树0年取样时为Ⅰ级肥力,不施肥种植1年后毛蟹根部土壤为Ⅲ级肥力,本山和梅占则为Ⅱ级肥力,2年后均为Ⅲ级肥力。茶树叶片品质分析结果表明,随着不施肥种植时间的延长,茶叶中茶多酚、茶氨酸、咖啡碱的含量呈现下降趋势。同一种茶树在不同种植年限间,茶多酚含量的变化较为微弱,而茶氨酸、咖啡碱含量则呈显著差异。不同种植年限下茶树叶片中表没食子儿茶素没食子酸酯、表儿茶素没食子酸酯与表没食子儿茶素含量及其品质指数均随着不施肥种植时间的延长而呈下降趋势,且同一种茶树不同种植年限间的变化率均呈显著差异。     

高效亲和的花生寄主植物-根瘤菌株组合

本文针对栽培花生，从大、小共生体双方研究了寄主植物－根瘤菌株组合的亲和性。结果指出：（１）在温室水培盆栽条件下，用菌株１４７－３接种的寄主植物结瘤、固氮能力育成品种〉普通型；（２）血清学鉴定出５个不同血清型菌株，其竞争力或回收率与寄主品种、根瘤菌株和土著菌数密切相关；（３）在温室与田间条件下，不同花生寄主一根瘤菌株组合存在着广谱或特异共生亲和性与非亲和性的差异，并鉴定出高效、广谱亲和的品种徐州６－     

四个茶树品种的氟吸收累积特性比较研究

评价4个茶树品种的氟吸收富集能力差异,为有效降低茶叶中氟含量和茶叶生产中推广低氟品种提供参考依据。以前期初选出的4个不同氟含量茶树品种的一年生无性系茶苗为材料,采用溶液培养的方法,研究各品种的短期吸收动力学参数差异、 氟吸收累积动态及累积能力差异。结果表明,在低氟浓度生长环境下,茶树对氟的吸收符合Michaelis-Menten动力学方程Vi=VmaxCi/（Km+Ci）描述,表现出主动吸收过程,茶树各部位对氟的吸收累积能力表现为成熟叶根茎; 随着氟浓度的增加,茶树对氟的吸收逐渐表现出了明显的被动吸收现象。茶树各部位对氟的吸收累积能力表现为成熟叶茎根;中茶102品种对氟的吸收累积能力及对氟的耐受性与中茶108相比有较大的差异,中茶108对氟具有比较稳定的低吸收累积特性,而中茶102则对氟表现出了较强的吸收累积特性,龙井43与乌牛早则介于两者之间。中茶108具有稳定的低氟吸收累积特性,可以作为低氟品种推广。     

利用高分子量谷蛋白亚基的特异PCR标记辅助选育优质面包小麦

本研究利用亚基5和10的特异PCR标记，对19个已知HMW－GS组成的品种（包括中国春及其缺体1D－四体1A、缺体1D－四体1B）进行了扩增。结果表明，具有5亚基的8个品种[如钱尼（CNN）和荔垦2号]，能扩增出450bp的特异带；而其它品种[如中国春（CS）及其1D缺体－四体]，则没有这一特异带。具有10亚基的品种[CNN和荔垦2号等]能扩增出576bp的特异带；具有12亚基的品种（如CS等）能扩增出612bp的特异带。结果与HMW－GS的蛋白质电泳结果一致。用这两个标记对同一组合内的15个F6品系进行PCR扩增，发现其中12个品系HMW－GS组成为1Dx5 1Dy10。     

不同茶树品种(系)的绿茶滋味分析及评价模型构建

为客观准确地评价不同茶树品种(系)绿茶的滋味品质,该研究系统分析了25个茶树品种(系)绿茶的主要滋味成分含量及其Dot值,利用主成分分析法对不同茶树品种(系)绿茶滋味品质进行综合评价并建立滋味品质评价模型。结果表明:儿茶素、咖啡碱是不同茶树品种(系)绿茶苦涩味强度差异的主要原因,其中表没食子儿茶素没食子酸酯(Epigallocatechingallate,EGCG)是所测样品中涩味的主要贡献物质,EGCG和咖啡碱为所测样品中苦味的主要贡献物质。氨基酸是不同茶树品种(系)绿茶鲜味、甜味差异主要因素,谷氨酸是所测样品中鲜味的主要贡献物质。主成分分析表明:前5个主成分的累计方差贡献率为79.018%,并以前5个主成分的线性回归方程和贡献率构建了滋味品质评价模型,模型评价结果与感官审评结果较为相似,存在极显著相关性(P0.01),相关系数为0.791;利用模型中各主成分的得分,能够较好的区分所测样品的苦、涩、鲜、爽等滋味特征。因此,该研究所建模型能够较好的评价所测样品的滋味品质及其主要滋味特征的差异,为各茶树品种(系)的推广应用提供理论依据,也为不同茶树品种(系)绿茶滋味品质的科学评价提供新的思路和方法。     

Radical scavenging conserves from unused fresh green tea leaves

Green teas were made by inactivating the enzymes present in fresh leaves of coarse/pruned (unused) and normal (used for tea) grades using different sources of thermal energies. Green teas were extracted in a Soxhlet using different solvents. The obtained miscella was subjected to concentration to give the extract. The extract was subjected to solvent-solvent extraction. Solvent extract was concentrated to obtain conserve. The yields of conserves are 17 +/- 0.8 and 15 +/- 0.8% from green teas of normal and coarse tea leaves, respectively. The radical scavenging activity of these extracts was evaluated using a DPPH in vitro model system. The total polyphenol content was also determined and found to be higher in conserves from normal tea leaves. However, radical scavenging activity of conserves from coarse and normal green tea leaves was found to be >90% at 15 ppm concentration. The HPLC profiles of these conserves were used to quantify the total catechin content with the help of calibration curves prepared using authentic samples at known concentrations. The total catechin content is found to be in the range of 55-85%. Results indicated that the extracts from coarse leaves also possess potential biological activity and could be used as nutraceuticals as well as for preservation purposes in food formulations.     

氟对茶树生长、叶片生理生化指标与茶叶品质的影响

以2个茶树品种为试验材料,通过土壤盆栽试验,研究了土壤添加氟浓度为0～200 mg/kg对茶树生长、叶片生理生化指标与茶叶品质的影响以及茶树的氟累积特性。结果表明,随氟处理浓度增加,茶树的生长、叶绿素合成和光合作用均受到明显抑制; 福鼎大白茶的SOD、CAT和POD活性均随氟处理浓度的增加呈先升高后降低趋势,名山白毫的3种酶活性则受到明显抑制。2个品种的新梢中游离氨基酸、儿茶素组分和咖啡碱含量也随施氟浓度的增加总体呈下降趋势,茶叶品质降低,表明氟可能抑制茶树儿茶素的合成代谢和氮素代谢。茶树的氟累积量也随着土壤氟水平的增加而增加,且各器官的氟含量(y)与土壤中添加的氟(x)呈显著或极显著线性正相关; 茶树的聚氟能力依次为叶片＞新梢＞枝条＞茎＞根,叶片是氟累积的主要器官。福鼎大白茶耐氟、抗氟的能力明显强于名山白毫,但氟积累能力则低于名山白毫。     

Phenolic antioxidants from green tea produced from Camellia taliensis

The chemical constituents of green tea prepared from the leaves of Camellia taliensis (W. W. Smith) Melchior (Theaceae) were investigated for the first time. Of these, 19 phenolic compounds including 8 hydrolyzable tannins (1-8), 6 catechin derivatives (9-14), 3 quinic acid aromatic esters (15-17), and 2 simple phenolics (18, 19) were identified, along with caffeine (20). Their antioxidant activities were evaluated by DPPH radical scavenging and tyrosinase inhibitory assays. Moreover, the chemical composition was compared with that in the cultivated tea plant, C. sinensis var. assamica, by HPLC analysis. It was noted that C. taliensis has similar chemical features with the cultivated tea plant; that is, both of them contain rich flavan-3-ols and caffeine. In addition, there are abundant hydrolyzable tannins as specific characteristic constituents contained in the leaves of C. taliensis. Therein, 1,2-di-O-galloyl-4,6-O-(S)-hexahydroxydiphenoyl-beta-D-glucopyranose (8), as a major compound in C. taliensis, showed remarkable antioxidant activity. The results suggested that C. taliensis could be a valuable plant resource for the production of tea.     

Free radical scavenging properties of wheat extracts

Three hard winter wheat varieties (Akron, Trego, and Platte) were examined and compared for their free radical scavenging properties and total phenolic contents (TPC). Free radical scavenging properties of wheat grain extracts were evaluated by spectrophotometric and electron spin resonance (ESR) spectrometry methods against stable 2,2-diphenyl-1-picryhydrazyl radical (DPPH*) and radical cation ABTS*+ (2,2'-azino-di[3-ethylbenzthiazoline sulfonate]). The results showed that the three wheat extracts differed in their capacities to quench or inhibit DPPH* and ABTS*+. Akron showed the greatest activity to quench DPPH radicals, while Platte had the highest capacity against ABTS*+. The ED50 values of wheat extracts against DPPH radicals were 0.60 mg/mL for Akron, 7.1 mg/mL for Trego, and 0.95 mg/mL for Platte under the experimental conditions. The trolox equivalents against ABTS*+ were 1.31 +/- 0.44, 1.08 +/- 0.05, and 1.91 +/- 0.06 micromol/g of grain for Akron, Trego, and Platte wheat, respectively. ESR results confirmed that wheat extracts directly reacted with and quenched free radicals. The TPC were 487.9 +/- 927.8 microg gallic acid equivalents/g of grain. No correlation was observed between TPC and radical scavenging capacities for DPPH* and ABTS*+ (p = 0.15 and p > 0.5, respectively).     

Novel antiallergic catechin derivatives isolated from oolong tea.

Two catechin derivatives (C-1 and C-2) with potent antiallergic activity were isolated from Taiwanese oolong tea by HPLC techniques. From NMR and FAB-MS analyses, the structures of C-1 and C-2 were elucidated as (-)-epigallocatechin 3-O-(3-O-methyl)gallate and (-)-epigallocatechin 3-O-(4-O-methyl)gallate, respectively. The oolong tea leaves contained 0.34% (dry weight) C-1 and 0.20% C-2. Traces of C-2 were detected in only 1 of 15 varieties of green tea tested. C-1 was detected in 13 of 15 green tea varieties; C-1 was most concentrated in tea cultivars classified as Assam hybrids (0. 50-0.82% of dry weight). Quantitative analyses of green tea, oolong tea, and black tea manufactured from same batches of tea leaves showed that neither catechin derivative was produced during the fermentation process. Oral doses of C-1 and C-2 (5-50 mg/kg) significantly inhibited type I allergic (anaphylactic) reactions in mice sensitized with ovalbumin and Freund's incomplete adjuvant. These inhibitory effects exceeded that of the major tea catechin, (-)-epigallocatechin 3-O-gallate, which has known antiallergic properties.     

A treasure reservoir of genetic resource of tea plant (<Emphasis Type="Italic">Camellia sinensis</Emphasis>) in Dayao Mountain

Components of 29 wild type tea single plants collected from Dayao Mountain, in Guangxi province, South China, were investigated. They included tea polyphenols, free amino acids, catechin, amino acid and alkaloid monomers etc. Genetic diversity and clustering analyses were conducted based on the main biochemical components. Meanwhile, genetic relationships among 6 wild type tea plants representing 3 tea populations of Daoyao Mountain with 15 tea varieties grown in Yunnan, Guangdong, Hunan, Fujian provinces were analyzed by random amplified polymorphic DNA. The results showed that wild type tea plants from Dayao Mountain were of rich genetic diversity. Furthermore, some tea germplasms with high quality, including high contents of amino acids, high epigallocatechin gallate, and high caffeine have been discovered. These wild type tea germplasms are of high values for further development values due to their geographical uniqueness.     

Electron paramagnetic resonance investigations of free radicals in extra virgin olive oils

Free radicals in olive oils were identified and quantified by EPR, by means of the spin-trapping technique making use of alpha-phenylbutylnitrone (PBN) as spin trap. The radical species were identified as PBN-trapped hydroxyl radicals (PBN-*OH) in the water microdroplets inside the fat medium. The largest radical concentration was 12.5 microM identical with 100%. The following were the relative concentrations of the radicals under different conditions: (1) Two oils, produced by continuous centrifugation, aged for 1 year, showed a 25-30% increase in the radicals compared to nonaged oils; 1-year-old oil, produced by pressure, did not differ from the nonaged oil. (2) Radical production was markedly reduced by N(2) bubbling; it was increased by heating, whereas it showed a biphasic pattern by air bubbling over time. (3) Radical concentration as a function of the UV irradiation time increased up to a maximum, after which it decreased and finally remained constant. The phenolic and oxygen contents were related to the radical content. This study demonstrates that the EPR technique is suitably applied to the detection of free radicals in olive oil and that storage, handling, and stress conditions of the oils significantly influence the radical concentration.     

抗氧化剂对辐照猪肉理化和感官品质的影响

为减少猪肉辐照灭菌后产生的异味和脂肪氧化,研究了叔丁基对苯二酚、虾青素、维生素E、茶多酚4种抗氧化剂对辐照猪肉理化和感官品质的影响。采用2 g/L抗氧化剂浸泡处理,透氧包装,辐照剂量2.6 kGy,冷藏10 d。分析测定辐照猪肉感官品质、过氧化值、硫代巴比妥酸反应物、挥发性物质、抗氧化剂对羟自由基清除能力,筛选出适合猪肉辐照的高效抗氧化剂。结果表明：叔丁基对苯二酚在储藏期可以很好地减轻辐照异味并抑制脂肪氧化,效果优于虾青素、维生素E、茶多酚。叔丁基对苯二酚和维生素E可以有效地降低脂肪辐照后产生的挥发性物质含量。叔丁基对苯二酚（0.5 g/L）对羟自由基的清除率为52.5%,高于其他抗氧化剂,可抑制猪肉辐照过程中羟自由基参与的反应。     

Green tea polyphenols react with 1,1-diphenyl-2-picrylhydrazyl free radicals in the bilayer of liposomes: direct evidence from electron spin resonance studies

Free radical scavenging reactions of green tea polyphenols (GTP) were investigated with electron spin resonance (ESR) spectroscopy in the phospholipid bilayer of liposomes, using 1, 1-diphenyl-2-picrylhydrazyl (DPPH) radical as a model. The results showed that (1) GTP reacts with DPPH radicals in the bilayer of liposomes of both 1-hexadecanoyl-2-[(cis,cis,cis,cis,cis,cis)-4,7,10, 13,16,19-docosahexaenoyl]-sn-glycero-3-phosphocholine (DHAPC) and 1, 2-di[cis-9-hexadecenoyl]-sn-glycero-3-phosphocholine) (DPPC); and (2) GTP protects DHAPC liposomes effectively from the oxidation initiated by DPPH radicals. These results provide direct evidence that GTP reacts with free radicals in the model membrane and support the hypothesis that GTP protects unsaturated phospholipids from oxidation by reacting directly with the radicals.     

Identification and quantification of free radical scavengers in Pu-erh tea by HPLC-DAD-MS coupled online with 2,2'-Azinobis(3-ethylbenzthiazolinesulfonic acid) diammonium salt assay

Pu-erh tea, a well-known traditional beverage in China, has attracted more attention because of its beneficial health effects and special flavor and taste. Generally, it is believed that Pu-erh tea with a longer preservation period has better quality and taste. Antioxidant activity is one of the major beneficial activities of tea. In this study, a HPLC-DAD-MS coupled with 2,2'-azinobis (3-ethylbenzthiazolinesulfonic acid) diammonium salt (ABTS) assay was employed for identification and quantification of free radical scavengers in different samples of Pu-erh tea. Among 12 main peaks detected in Pu-erh raw tea, 11 compounds were identified as gallic acid, (-)-gallocatechin, (-)-epigallocatechin, (+)-catechin, caffeine, (-)-epicatechin, (-)-epigallocatechingallate, rutin, (-)-epicatechingallate, quercetin-3-glucoside, and kaempferol-3-glucoside by comparison of their UV and MS data with standard compounds or literature data, respectively. The contents of 12 investigated compounds were also determined or estimated using caffeine, (-)-epicatechin, or rutin as standard. ABTS assay showed that 10 out of 12 compounds were free radical scavengers. Their total amount was used as the marker for evaluation of free radical scavenging activities of different Pu-erh teas, which indicated that the activity of different Pu-erh teas varied; Pu-erh raw tea was stronger than the ripe one, and the activity decreased with the increase of preservation period.