中国黑茶的起源与加工工艺

文章简述了四川黑茶、湖南黑茶、湖北老青砖、云南普洱以及广西六堡等黑茶的历史起源以及文化内涵,指出品质、工艺的独特性以及地域文化的差异造就了不同种类黑茶独特的发展历程;归纳总结了黑茶加工的基本工序及工艺,对比分析得出各地黑茶传统加工工艺的差异在于消费品质导向的不同以及精制过程中特色的紧压工序;结合品质调控以及规模化标准化生产的内在要求,提出对传统工艺的传承与创新以及机械化采制将是今后黑茶加工工艺改进的发展方向。     

不同加工工艺下‘紫娟’茶品质的比较

为研究不同加工工艺对‘紫娟’茶品质的影响,以‘紫娟’鲜叶为原料,分别利用烘青绿茶、晒青绿茶、红茶、白茶及黑茶的加工工艺制作成5种‘紫娟’茶,检测其主要品质成分的含量并进行系统分析。结果表明,不同加工工艺下,同一品种‘紫娟’鲜叶制得的茶样所含化学成分的含量差异较大。其中,‘紫娟’烘青绿茶中花青素含量最高,晒青绿茶次之;儿茶素的含量随着发酵程度的加深而降低。此外,在黑茶中没食子酸含量最高,在白茶中茶氨酸含量最高,而咖啡碱在红茶中的含量最高。由此可见,不同加工工艺对‘紫娟’茶的主要品质化学成分影响较大,其中‘紫娟’烘青绿茶的多酚类物质含量最为丰富。     

黑茶的发展简史

黑茶是六大茶类之一,为我国所特有。黑茶起源于四川粗边茶,开始以炒绿半干毛茶堆积做色、蒸压成团块成品茶;后来逐渐演变而发展到湖南安化的正规黑茶。黑茶湿看叶底褐色,汤色深橙黄而带红,香味有特殊风格,即不像绿茶,又不像黄茶,更不像青茶,品质有独立系统。凡品质与这个系统相近的茶叶都可以归纳为黑茶类,如湖南湘尖、茯砖、花砖,湖北老青茶,四川边茶,云南普洱茶以及广西六堡茶等,其花色品名繁杂,生产历史悠久。     

圣水黑茶出新品——千两茶

正继利用"黑毛茶"研制开发出"工艺茶砖"之后,近日湖北圣水茶场有限公司又从湖南安化请来一批专业技工,利用竹山县丰富的夏秋茶资源,加工出黑茶新品——千两茶。千两茶是湖南安化的一种传统名茶,其每卷茶叶净含量合老秤一千两,故名"千两茶";因其外表用篾篓包装成花格状,故又名"花卷茶"。该产品以存放多年的优质黑毛茶为原料,以竹篾、棕叶、寥叶等天然材     

黑茶品质成分及加工研究进展

黑茶作为中国六大茶类中的一种,近年来因其独特的保健作用及便于储藏、耐冲泡的特点而备受欢迎,其渥堆过程中微生物、渥堆工艺及保健作用等也被广泛研究。它是一种后发酵茶,经渥堆其生化成分发生一系列的化学反应,形成不同于其他茶类的独特风味。渥堆是黑茶加工中最关键的工序,其实质是以微生物活动为中心,在湿热、微生物以及胞外酶的相互作用下使多酚类物质自动氧化。综述黑茶某些品质成分,初加工中渥堆工艺、渥堆微生物及生化成分变化情况,初加工配套工艺技术以及深加工相关研究,概括黑茶目前的主要研究情况并展望今后黑茶的深入研究方向,即开展微生物、酶、品质成分三者间内在关联的研究,揭示黑茶特征风味形成机理,以及加工机械化、规模化、清洁化等研究,以期为黑茶的进一步研究提供基础和借鉴。     

广西特产—六堡茶

六堡茶以原产于广西梧州市苍梧县六堡乡而得名；生产历史悠久，远在唐代已有生产，产销量大，属我国特有的茶类—黑茶；广西六堡毛茶现全部集中到广西梧州茶厂加工，年产量１０００～１５００ｔ，该茶精制成品分为竹笠装紧压六堡茶，散装六堡条茶（或称陈茶）。六堡茶以红、浓、陈、醇四绝著称，是主要出口商品，主销东南亚各国以及港澳地区、日本、美国、南朝鲜等。六堡茶有清暑祛湿、明目健心、帮助消化、减肥除腻、利尿解毒等功效。六堡毛茶品质特征：外形条索粗壮、色泽黑褐光润、内质汤色红黄、香气醇厚并带有松烟气、滋味浓醇爽口、叶…     

“宿松香芽”茶加工工艺

宿松香芽高山优质茶,无公害产品,一直因没有统一的加工工艺导致茶叶的外形和品质差异大,不利于品质提高和市场销售,笔者通过多年来的生产实践,整理了“宿松香芽”茶加工工艺,对统一制作工艺和茶产业的发展有极大的促进作用.     

不同茶树花茶内含物质分析

茶树花作为茶叶的副产资源，其茶多酚、茶咖啡碱和L-茶氨酸等物质含量与茶鲜叶含量接近，是一种可以高效利用的资源。以乌牛早、白鸡冠、黄金芽和普洱大茶树4个品种不同成熟期的茶树鲜花为材料，按照本课题组前期优化的茶树花茶加工工艺进行加工，对加工后的花茶进行感官评价，并测定其茶咖啡碱、茶多酚、L-茶氨酸含量。结果表明：不同品种、不同开放程度茶树鲜花所制作花茶的品质及内含物质差异较大；露白期茶树鲜花制作出的花茶颗粒饱满完整，槐花香高长，滋味清甜爽口、显花味、茶汤蜜黄明亮，口感最佳；其咖啡碱含量为0.17～0.26 mg/g；茶多酚含量总体相对较低，为0.48～0.64 mg/g;L-茶氨酸的含量总体相对较高，为0.82～1.14 mg/g。     

相同加工原料下的六大茶类体外抗氧化性能比较

以春季茶树碧香早的一芽二叶茶鲜叶为原料,将其固定及分别加工成六大茶类,比较研究了相同加工茶鲜叶及其干茶质量下的六大茶类体外抗氧化性能,以期为茶叶新产品开发及健康消费提供科学依据。结果表明,固定样及六大茶类的还原能力和清除DPPH.、亚硝基、.OH及O2-.的能力均随茶汤浓度的增加而增强;固定样、绿茶、黄茶、黑茶、乌龙茶、白茶以及红茶对DPPH.的IC50依次为0.017、0.019、0.019、0.020、0.021、0.022和0.038mg干茶浸出物/ml,绿茶、固定样、乌龙茶、黑茶、白茶、黄茶和红茶对.OH的IC50依次为1.438、1.695、2.988、4.163、4.606、4.881和6.847mg干茶浸出物/ml,固定样、乌龙茶、黄茶、绿茶、白茶、黑茶和红茶对亚硝基的IC50依次为1.285、1.401、1.514、1.525、1.847、2.146和5.163mg干茶浸出物/ml。说明由相同原料加工而成的六大茶类在浸泡相同质量干茶的条件下,因其加工工艺的不同而在体外抗氧化性能上存在差异,固定样及六大茶类的抗氧化能力大小在总体上呈现不发酵茶(绿茶)＞半发酵茶(乌龙茶)＞全发酵茶(红茶)的趋势,其中以清除DPPH.的效果最好。     

相同加工原料下的6类茶体外抗氧化性能比较

以春季茶树‘碧香早’的1芽2叶茶鲜叶为原料,选同一批次鲜叶采用蒸汽固样法将其制成固定样及加工成6类茶叶,并比较研究其体外抗氧化性能,以期为茶叶新产品开发及健康消费提供科学依据。结果表明,固定样及6类茶的还原能力和清除DPPH·、亚硝基、·OH及O2-·的能力均随茶汤浓度的增加而增强;固定样、绿茶、黄茶、黑茶、乌龙茶、白茶以及红茶对DPPH·的IC_(50)依次为0.017、0.019、0.019、0.020、0.021、0.022、0.038 mg(干茶浸出物)/mL,绿茶、固定样、乌龙茶、黑茶、白茶、黄茶和红茶对·OH的IC_(50)依次为1.438、1.695、2.988、4.163、4.606、4.881、6.847 mg(干茶浸出物)/mL,固定样、乌龙茶、黄茶、绿茶、白茶、黑茶和红茶对亚硝基的IC_(50)依次为1.285、1.401、1.514、1.525、1.847、2.146、5.163 mg(干茶浸出物)/mL。说明由相同原料加工而成的6类茶在浸泡相同质量干茶的条件下,因加工工艺不同而在体外抗氧化性能上存在差异,固定样及6类茶的抗氧化能力大小在总体上呈现不发酵茶(绿茶)半发酵茶(乌龙茶)全发酵茶(红茶)的趋势,其中以清除DPPH·的效果最好。     

A note on the origin of Kalanchoë x vadensis Boom & Zeilinga (Crassulaceae)

Summary K x vadensis is a hybrid of K. blossfeldiana and K. marmorata obtained after doubling the number of chromosomes.     

Mechanisms and diversity of resistance to sorghum shoot fly,Atherigona soccata

Sorghum shoot fly, Atherigona soccata, is one of the important pests of postrainy season sorghums. Of the 90 sorghum genotypes evaluated for resistance to this pest, RHRB 12, ICSV 713, 25026, 93046 and 25027, IS 33844‐5, Giddi Maldandi and RVRT 3 exhibited resistance in postrainy season, while ICSB 463, Phule Anuradha, RHRB 19, Parbhani Moti, ICSV 705, PS 35805, IS 5480, 5622, 17726, 18368 and 34722, RVRT 1, ICSR 93031 and Dagidi Solapur showed resistance in rainy season, suggesting season‐specific expression of resistance to A. soccata. ICSB 461, ICSB 463, Phule Yasodha, M 35‐1, ICSV 700, 711, 25010, 25019 and 93089, IS 18662, Phule Vasudha, IS 18551 and 33844‐5 and Barsizoot had fewer deadhearts than plants with eggs across seasons, suggesting antibiosis as one of the resistance mechanism. Five genotypes exhibited resistance with high grain yield across seasons. Correlation, path and stepwise regression analyses indicated that leaf glossiness, seedling vigour, trichome density, oviposition and leaf sheath pigmentation were associated with the expression of resistance/susceptibility to shoot fly, and these can be used as marker traits to select and develop shoot fly‐resistant sorghums.     

Reaction of tritordeum to Fusarium culmorum and Septoria nodorum

Summary Hordeum chilense is a wild barley extensively used in wide crosses in the Triticeae. It could be a valuable source of resistance to Fusarium culmorum and Septoria nodorum. Some H. chilense x Triticum spp. amphiploids, named tritordeums, were more resistant than the parental wheat line to these diseases, others were not. Average contents of ergosterol and deoxynivalenol (DON) suggested that resistance to colonization by Fusarium was the highest for Hordeum chilense, followed by tritordeum and wheat in decreasing order. In particular, the H. chilense genotypes H7 and H17 enhanced the wheat resistance to F. culmorum in its tritordeum offsprings. Resistance to S. nodorum in tritordeum was not associated with tall plant height. There is sufficient genetic variation for resistance to F. culmorum and S. nodorum among tritordeum to allow the breeding of lines combining short straw and resistance to both diseases.     

Disease resistance in protected crops and mushrooms

Summary Cultivars of tomatoes, cucumbers, lettuce and peppers have been bred for resistance to one or more pathogens. Some tomato and cucumber cultivars have resistance to a wide range of diseases. Resistance has been transient in many cases and a succession of cultivars with new genes or new combinations of resistance genes has been necessary to maintain control. There has been a number of notable exceptions and these have included durable resistance to such pathogens asFulvia fulva and tomato mosaic virus. With lettuce the resistance situation is complicated by the occurrence of fungicide resistant pathotypes. There are no strains ofAgaricus bisporus purposely bred for disease resistance.In protected flower crops only resistance to Fusarium wilt in carnations has been purposely bred but differences in disease resistance are apparent in cultivars of many ornamental crops. This is particularly so in chrysanthemums where there are cultivars with resistance to many of the major pathogens. Similar situations occur with other flower crops and pot plants. Cultivars of some species have not been systematically investigated for resistance.The need for genetic resistance will increase with the further reduction, in the limits on pesticide use and an increasing public awareness and importance of pesticide pollution.ADAS is an executive agency of the Ministry of Agiculture, Fisheries and Food and the Welsh Office.     

Genetic constitution and diversity in four narrow endemic redwoods from the family Cupressaceae

The genetic constitution and diversity of four relictual redwoods are discussed in this review. These include monotypic genera of the family Cupressaceae: coast redwood (Sequoia sempervirens), giant sequoia (Sequoiadendron giganteum), dawn redwood (Metasequoia glyptostroboides), and alerce (Fitzroya cupressoides). All four species are narrow endemics, share a number of common phenotypic traits, including red wood, and are threatened species. Fossil history suggests that the ancestors of redwoods probably originated during the Cretaceous and Tertiary periods and flourished thereafter for millions of years. Towards the end of the Tertiary period began their decline and struggle for existence that continued during the subsequent geologic upheavals and climate changes, until the survival of the present-day redwoods in the current restricted locations in the world (USA, China, and South America). Although two species, Sequoiadendron and Metasequoia, are diploids (2n = 22), and the other two are polyploids: Fitzroya a tetraploid (2n = 4x = 44), and Sequoia a hexaploid (2n = 6x = 66); they all share the same basic chromosome number x = 11. The genome size in the hexaploid Sequoia is one of the largest (31,500 MB) in the conifers, while the genome sizes of diploid Metasequoia and Sequoiadendron are about one-third (~10,000 MB) of Sequoia. Genetic diversity in the redwoods is lower than most other gymnosperms, except in Sequoia, which seems to rank near the upper quarter of the coniferous forest trees. Genomic research is sparse in the redwoods, and should be pursued for a better understanding of their genome structure, function, and adaptive genetic diversity.     

The induction in vitro of adventitious shoots in Rosa

Summary Adventitious shoots were formed on excised leaves, roots and callus of Rosa persica x xanthina and on excised leaves of R. laevigata and R. wichuraiana on culture media that included BAP and NAA as growth regulators. Shoots formed freely on freshly cultured callus of R. persica x xanthina but their production declined in successive cultures and ceased after twelve weeks. Transplantation to soil was improved by rooting plantlets in cellulose plugs in vitro and transferring plantlets to soil while still in the plugs.     

Distribution,ecology and reproductive biology of wild tomatoes and related nightshades from the Atacama Desert region of northern Chile

Over the past 20 years, several expeditions were made to northern Chile to collect populations of wild tomatoes (Solanum chilense, S. peruvianum) and allied nightshades (S. lycopersicoides, S. sitiens), and obtain information about their geographic distribution, ecology and reproductive biology. Restricted mainly to drainages of the Andean and the coastal cordillera, populations are geographically fragmented. The two nightshade species are rare and threatened by human activities. Adaptation to extreme aridity and soil salinity are evident in S. chilense and S. sitiens (the latter exhibits several xerophytic traits not seen in the tomatoes) and to low temperatures in S. lycopersicoides and S. chilense. All tested accessions are self-incompatible, with the exception of one S. peruvianum population collected at the southern limit of its distribution. Several distinguishing reproductive traits—anther color, attachment, and dehiscence, pollen size, and flower scent—suggest S. sitiens and S. lycopersicoides attract different pollinators than S. chilense and S. peruvianum. The four Solanum spp. native or endemic to Chile provide a variety of novel traits which, through hybridization and introgression with cultivated tomato, could facilitate development of improved varieties, as well as research on a variety of basic topics, including plant-pollinator interactions, abiotic stress responses, and evolution of reproductive barriers.     

The exploration of genetic resources of Portuguese cabbage and kale for resistance to several Brassica diseases

Summary Twenty three accessions of nine Portuguese cabbage and kale land races from different geographic origins were tested at the seedling stage for resistance to several important brassica diseases. Resistance to downy mildew (Peronospora parasitica), expressed as necrosis of the cotyledon mesophyll, was found in all the accessions. Type A resistance to cabbage yellows (Fusarium oxysporum f. sp. conglutinans race 1) was present in most of the landraces. Resistance to clubroot (Plasmodiophora brassicae race 6) was found in one accession of the Portuguese tree kale. High resistance to blackleg (Leptosphaeria maculans) and white rust (Albuco candida) was not detected, although several accessions showed 20 to 30% of plants with intermediate expression of resistance. All Portuguese cole accessions were susceptible to blackrot (Xanthomonas campestris pv. campestris).     

Production and characterization of intergeneric diploid cybrids derived from symmetric fusion between Microcitrus papuana Swingle and sour orange (Citrus aurantium)

Plants were regenerated from intergeneric somatic hybridization between embryogenic protoplasts of Microcitrus papuana Swingle and leaf-derived protoplasts of sour orange (Citrus aurantium L.) via electrofusion. The regenerated plants were morphologically similar to the leaf parent in growth vigor, leaf and branch structure. FCM analysis showed that they were diploids. Simple-sequence-repeat (SSR) and cleaved-amplified-polymorphic-sequence(CAPS) were employed for hybridity characterization. SSR banding patterns of the regenerated plants were identical to the leaf parent, sour orange, indicating that they possessed nuclear component derived from sour orange. DNA amplification with chloroplast and mitochondrial universal primers, followed by restriction endonuclease digestion, revealed polymorphism between the fusion parents. Therefore, this method was used to determine the cytoplasmic compositions of the regenerated plants. Banding patterns for all the polymorphic primer/enzyme combinations of the regenerated plants were similar to those of the embryogenic parent, M. papuana, suggesting that only the cytoplasmic components derived from the embryogenic parent were present in the regenerated plants. FCM, SSR and CAPS demonstrated that intergeneric diploid cybrids have been successfully obtained by symmetric fusion. Related results concerning nuclear and cytoplasmic composition of previous diploid somatic hybrids and potential mechanism for regeneration of such kind of plants are discussed herein. This revised version was published online in July 2006 with corrections to the Cover Date.     

Breeding barriers between the cultivated strawberry, Fragaria × ananassa, and related wild germplasm

Five-hundred interspecific and intergeneric crosses were performed among accessions of the wild strawberries Fragaria vesca(2x), Duchesnea indica (8x), Potentilla tucumanensis (2x) and 9 genotypes of the cultivated strawberry, Fragaria×ananassa (8x), following an incomplete diallele mating design. Crosses between D. indica and F.×ananassa produced many putative hybrids when D. indica was used as female but a few achenes and plants when used as male; therefore, pollen-pistil compatibility relations were analyzed by fluorescence microscopy in this direction of the cross. Of the genotypic combinations, 78.6% were incompatible at the stigma level and 17.2% at the first third of the style. Only 3.6% were pollen-pistil compatible and produced fruits with achenes (seven did not germinate or originated short-lived plants and nine produced normal plants). F.vesca×F.×ananassa crosses produced 35 hybrid achenes but only 14% germinated, yielding short-lived plants; histological analyses revealed that inviable seeds had less developed (or collapsed) endosperms and smaller embryos than control plump F. vesca seeds. P.tucumanensis was only used as male, with negative results. These species and genera are partially isolated by a complex system of pre- and post-zygotic barriers. Knowledge of their nature would allow the breeder to devise strategies to put the genetic variability available in the group into a useful form. This revised version was published online in July 2006 with corrections to the Cover Date.