夏季茶鲜叶加工花香型黄茶的品质变化研究

以茶树品种碧香早夏季一芽一叶鲜叶为原料,在传统黄茶的摊放工艺中引入可激发花香品质形成的晒青和摇青工艺,探讨了利用晒青和摇青工艺技术加工花香型黄茶的可行性,以期为黄茶的提质加工和夏秋茶资源的综合利用提供参考。试验通过感官与理化品质分析,结果表明,在传统黄茶加工的摊放工序中科学融入晒青、摇青工艺技术,可加工出具有花香品质的夏季黄茶,相较于传统工艺黄茶,氨基酸、可溶性糖、茶黄素含量分别相对增加了3.90%、33.78%和19.05%,而茶多酚、酯型儿茶素含量相对分别降低了2.31%及2.88%,酚/氨比值、酯型儿茶素/总儿茶素比值分别降低了6.02%与10.77%,茶汤苦涩滋味减轻;同时香气品质成分更加丰富,正辛醛、水杨酸辛酯、苯甲醛、橙花基丙酮、4-[2,2,6-三甲基-7-氧杂二环[4.1.0]庚-1-基]-3-丁烯-2-酮等香气组分显现或相对含量提高。传统黄茶加工工艺中引入晒青和摇青,可加工有特色的花香型黄茶。     

夏季适制黄茶的茶树品种及采摘标准研究

本试验以四川主栽品种福鼎大白茶、名山131、福选9号、乌牛早和川农黄芽早的一芽一叶、一芽二叶和一芽三叶为原料,采用传统黄茶加工工艺制成黄茶,通过对其内含成分测定和感官审评,分析得出夏季加工制作成黄茶的最佳品种、最佳采摘标准。结果表明:福选9号一芽一叶、一芽二叶为最适宜制作黄茶的原料,其次为川农黄芽早嫩叶(一芽一叶)。     

黄茶漫话

黄茶是我国六大茶类之一，加工精妙，品质独特，在我国茶叶产销中占有重要地位。笔者对黄茶起源进行了初步探究，并对黄茶生产及贸易情况作了简要介绍，呼吁业界加快传统黄茶的创新开发，促进产业发展。     

黄茶品质形成机理研究进展

本文从品质成分变化、微生物类群及酶活性变化、加工工艺等方面综述了黄茶品质形成机理,并展望了今后黄茶品质成因及品质化学的研究方向。     

适应金萱品种加工黄茶的闷黄工艺探讨

金萱品种通常用以制作乌龙茶,兼制绿茶、红茶,但以金萱品种制作黄茶的情况较为少见,本实验以河源市东源县种植的金萱品种为原料,以不同方式闷黄工艺制作黄茶,并分析毛茶各种生化成分差异和感官审评比较,探讨不同方式闷黄对金萱黄茶的成茶品质影响,以期获得比较适合金萱黄茶的闷黄方式和参数,结果表明,三种闷黄试验方式对黄茶品质的影响中,干燥同时闷黄的处理,品质最好,比较适合金萱品种加工黄茶工艺。     

黄茶品质影响因素及香气研究进展

黄茶是我国六大茶类之一,具有悠久的历史和独特的品质。其基本工艺为:杀青-揉捻-闷黄-干燥,各个工艺阶段的差异形成了不同品牌黄茶的品质特性。本文从茶树品种、加工工艺对黄茶品质的影响以及黄茶香气成分的研究进行综述,以期为黄茶研究提供参考。     

花香型黄茶研究报告

本文以花香型黄茶品质特征为基础,开展茶树品种适制性、花香型黄茶初制烘焙技术及配套加工技术等加工工艺研究,根据试验茶样品质鉴定与生化茶样检测结果,经系统分析可知,花香型黄茶以叶色偏黄类的高香型乌龙茶品种鲜叶原料为前提,配合适度的晒青、萎凋、摇青、堆青等做青技术,同时融入超干闷黄、精茶的控温控时烘焙等工艺为花香型黄茶加工标准加工规程。其最佳参数为：茶青减重达20%-25%时,进行5min摇青（15转/min）,超干闷黄以空间温度35℃-40℃,相对湿度30%-40%,闷黄3-4h,黄茶初制烘焙以闷黄叶阴至8成干再烘足干,精茶烘焙以80℃、3-4 h或90℃、1-3 h为佳。     

高档黄茶适制品种筛选研究

对尖波黄、槠叶齐、桃源大叶、碧香早、湘波绿2号、玉绿6个不同的品种制作高档毛尖黄茶进行了比较研究,结果显示尖波黄是比较适合加工毛尖黄茶的品种。     

“英红九号”黄茶加工关键技术探讨

根据英红九号茶树鲜叶特性和广东地区气候特点^([1]),提出对英红九号黄茶的加工工艺:鲜叶—轻萎凋—杀青—揉捻—闷黄—干燥各个工序的操作方法、控制程度、适宜的温度和相对湿度等,为进一步开发英红九号黄茶提供一定的研究制作依据。     

闷堆对黄茶滋味影响的研究

通过在鹿苑黄茶加工中分别进行 15min ,6h ,9h ,12h闷堆与不闷堆处理的比较 ,分析其主要滋味成分的变化。结果显示 ,闷堆过程中 ,茶多酚和儿茶素含量随时间的延长而减少加剧 ;氨基酸总量在闷堆前期随时间的延长而增加 ;闷堆 9h后茶多酚和氨基酸均有显著下降 ,并有少量茶黄素和茶红素产生 ;咖啡碱含量变化不明显。表明相同条件下 ,闷堆时间是黄茶滋味风格形成的主要因素 ,黄茶浓醇鲜爽滋味主要是闷堆过程中多酚类物质和氨基酸协调变化所致。黄茶闷堆时间以 6～ 8h为宜。     

Comparative Assessment of the Efficacy of Various Nitrogen Fertilizers

Summary

The efficiency of N fertilizers is usually poor; often less than 50% of the applied N is taken up by the crop. This review focuses on various N fertilizers with respect to the significance of different N loss pathways, namely (i) ammonia volatilization, (ii) dinitrogen and nitrogen oxide emissions, and (iii) nitrate leaching. Further, the significance of biological N immobilization, ammonium fixation and, finally, the impact of nitrate vs. ammonium uptake on crop yield are also discussed. The reviewed literature shows that N fertilizers may differ markedly in their susceptibility to losses. There is, however, considerable scope to improve N efficiency of each N source by proper N management practices.     

Studies on natural repellents against potato tuber moth (Phthorimaea operculella Zeller) in country stores

Summary The effects of the leaves of five plant species, one from each of the generaAmbrosia, Anemone, Eupatorium, Eucalyptus andLantana, on potato tuber moth were investigated under indigenous storage conditions at the Central Potato Research Station, Shillong (1800 m above sea level). Their action was compared with that of a biological insecticide (spores ofBacillus thuringiensis), a chemical insecticide (carbaryl), and an untreated control. The data collected after six months storage on tuber damage, sprout damage and the rotting indicated that the leaves ofLantana aculeata provided most protection to the tubers, reducing damage from over 70% in the check to below 5%, and sprout damage from over 45% to below 3%. Next best wasEucalyptus globulus followed byB. thuringiensis. They may be used on tubers stored for table use or for seed as they had no adverse effect on germination or on the yield of a subsequent crop.     

Mineral composition of some traditional Mexican teas

Teas of plant origin traditionally consumed by the Mountain Pima of Chihuahua, Mexico, were analyzed for mineral nutritional content. Fe, Cu, Zn, Ca, and Mg composition was determined for native teas made from shoots ofTagetes lucida, T. filifolia, Elytraria imbricata, andHolodiscus dumosus, and from root xylem ofCeanothus depressus andPhaseolus ritensis. Native uses of these teas are also described.     

Novel food and non-food uses for sorghum and millets

Sorghum and millets have considerable potential in foods and beverages. As they are gluten-free they are suitable for coeliacs. Sorghum is also a potentially important source of nutraceuticals such antioxidant phenolics and cholesterol-lowering waxes. Cakes, cookies, pasta, a parboiled rice-like product and snack foods have been successfully produced from sorghum and, in some cases, millets. Wheat-free sorghum or millet bread remains the main challenge. Additives such as native and pre-gelatinised starches, hydrocolloids, fat, egg and rye pentosans improve bread quality. However, specific volumes are lower than those for wheat bread or gluten-free breads based on pure starches, and in many cases, breads tend to stale faster. Lager and stout beers with sorghum are brewed commercially. Sorghum's high-starch gelatinisation temperature and low beta-amylase activity remain problems with regard to complete substitution of barley malt with sorghum malt . The role of the sorghum endosperm matrix protein and cell wall components in limiting extract is a research focus. Brewing with millets is still at an experimental stage. Sorghum could be important for bioethanol and other bio-industrial products. Bioethanol research has focused on improving the economics of the process through cultivar selection, method development for low-quality grain and pre-processing to recover valuable by-products. Potential by-products such as the kafirin prolamin proteins and the pericarp wax have potential as bioplastic films and coatings for foods, primarily due to their hydrophobicity.     

In vitro antimicrobial activity of different accessions ofSolanum commersonii Dun. from Uruguay

Summary The in vitro antimicrobial activity of extracts from accessions ofSolanum commersonii Dun. collected in the south of Uruguay was investigated against five microorganisms including the pathogenRalstonia solanacearum. A total of 30 extracts corresponding to organic and aqueous extracts were studied. Interestingly, most of the positive results for growth inhibition were againstR. solanacearum. The extracts were also analyzed for the presence of glycoalkaloids and lectins. Six of the ten aqueous extracts showed lectin presence and a wide variation in the type and amounts of glycoalkaloids, was found. Results indicate that there is no clear relationship between the antimicrobial activity against the five microorganisms screened and the presence or amounts of lectins and glycoalkaloids, traditionally regarded as possible antimicrobial metabolites in theSolanum genus, which indicates the presence of as yet unidentified antimicrobial compounds.     

Extreme resistance to infection by potato virus X in genotypes of wild tuber-bearingSolanum species

Summary Clones derived from thirty-one different accessions (nineteen of Argentine origin) belonging to eightSolanum species were screened for resistance to infection by potato virus X strain cp (PVX cp) by mechanical inoculation of plantlets that had been micropropagated in vitro. Estimates of PVX multiplication obtained by enzyme linked immunosorbent assay and slot blot nucleic acid hybridization allowed the identification of resistant clones derived from five accessions belonging toS. commersonii S. oplocense, S. sparsipilum andS. tuberosum andigena. Resistant genotypes supported PVX concentrations 5 to 15 times smaller than did the susceptible control cultivar Spunta. Graft inoculation test confirmed the presence of extreme resistance similar to that conferred by the ‘immunity’ gene X¹ (also called RX_act).     

Cyanobacteria Secondary Metabolites as Biotechnological Ingredients in Natural Anti-Aging Cosmetics: Potential to Overcome Hyperpigmentation,Loss of Skin Density and UV Radiation-Deleterious Effects

The loss of density and elasticity, the appearance of wrinkles and hyperpigmentation are among the first noticeable signs of skin aging. Beyond UV radiation and oxidative stress, matrix metalloproteinases (MMPs) assume a preponderant role in the process, since their deregulation results in the degradation of most extracellular matrix components. In this survey, four cyanobacteria strains were explored for their capacity to produce secondary metabolites with biotechnological potential for use in anti-aging formulations. Leptolyngbya boryana LEGE 15486 and Cephalothrix lacustris LEGE 15493 from freshwater ecosystems, and Leptolyngbya cf. ectocarpi LEGE 11479 and Nodosilinea nodulosa LEGE 06104 from marine habitats were sequentially extracted with acetone and water, and extracts were analyzed for their toxicity in cell lines with key roles in the skin context (HaCAT, 3T3L1, and hCMEC). The non-toxic extracts were chemically characterized in terms of proteins, carotenoids, phenols, and chlorophyll a, and their anti-aging potential was explored through their ability to scavenge the physiological free radical superoxide anion radical (O₂^•−), to reduce the activity of the MMPs elastase and hyaluronidase, to inhibit tyrosinase and thus avoid melanin production, and to block UV-B radiation (sun protection factor, SPF). Leptolyngbya species stood out for anti-aging purposes: L. boryana LEGE 15486 presented a remarkable SPF of 19 (at 200 µg/mL), being among the best species regarding O₂^•− scavenging, (IC₅₀ = 99.50 µg/mL) and also being able to inhibit tyrosinase (IC₂₅ = 784 µg/mL), proving to be promising against UV-induced skin-aging; L. ectocarpi LEGE 11479 was more efficient in inhibiting MMPs (hyaluronidase, IC₅₀ = 863 µg/mL; elastase, IC₅₀ = 391 µg/mL), thus being the choice to retard dermal density loss. Principal component analysis (PCA) of the data allowed the grouping of extracts into three groups, according to their chemical composition; the correlation of carotenoids and chlorophyll a with MMPs activity (p < 0.01), O₂^•− scavenging with phenolic compounds (p < 0.01), and phycocyanin and allophycocyanin with SPF, pointing to these compounds in particular as responsible for UV-B blockage. This original survey explores, for the first time, the biotechnological potential of these cyanobacteria strains in the field of skin aging, demonstrating the promising, innovative, and multifactorial nature of these microorganisms.     

Marine Pharmacology in 2009–2011: Marine Compounds with Antibacterial,Antidiabetic, Antifungal,Anti-Inflammatory,Antiprotozoal, Antituberculosis,and Antiviral Activities; Affecting the Immune and Nervous Systems,and other Miscellaneous Mechanisms of Action ?

The peer-reviewed marine pharmacology literature from 2009 to 2011 is presented in this review, following the format used in the 1998–2008 reviews of this series. The pharmacology of structurally-characterized compounds isolated from marine animals, algae, fungi and bacteria is discussed in a comprehensive manner. Antibacterial, antifungal, antiprotozoal, antituberculosis, and antiviral pharmacological activities were reported for 102 marine natural products. Additionally, 60 marine compounds were observed to affect the immune and nervous system as well as possess antidiabetic and anti-inflammatory effects. Finally, 68 marine metabolites were shown to interact with a variety of receptors and molecular targets, and thus will probably contribute to multiple pharmacological classes upon further mechanism of action studies. Marine pharmacology during 2009–2011 remained a global enterprise, with researchers from 35 countries, and the United States, contributing to the preclinical pharmacology of 262 marine compounds which are part of the preclinical pharmaceutical pipeline. Continued pharmacological research with marine natural products will contribute to enhance the marine pharmaceutical clinical pipeline, which in 2013 consisted of 17 marine natural products, analogs or derivatives targeting a limited number of disease categories.