浓缩茶叶的制备与保鲜研究初探

制取的浓缩茶汁,贮放在45℃的恒温箱中20天,观察沉淀产生的时间,测定沉淀量,结果表明:提取时间缩短,水温降低及采用蒸馏水或重蒸水所制备的浓缩茶汁沉淀产生的时间延迟且量减少.采用添加食品添加剂对浓缩茶汁的保色与浓缩茶汁贮藏保鲜试验,结果表明:对绿茶浓缩茶汁保色、保鲜效果以D-VcNa处理最好;对红茶浓缩茶汁的保色、保鲜效果以L-Vc和L-VcNa效果最好.     

鲜绿茶水工艺初探

本文以杀青方式、添加剂种类及浓度为试验因素，对鲜茶汗制备鲜绿茶水的工艺技术进行了初步探讨。结果表明：制备鲜绿茶水的杀青方式可根据现有生产条件任行选择；添加剂种类对鲜绿茶水沉淀量的影响达到显著性差异。L－抗坏血酸、异抗坏血酸钠的抗氧化作用对茶水护色效果较好，β－环糊精浓度的提高对茶水贮藏黄变有促进作用；L－抗坏血酸对抑制鲜绿茶水絮状沉淀物的产生效果最好，其浓度应低于200mg/l。     

茶汁制备的关键技术

茶饮料在常温保存下，易产生冷混浊（冷后浑），这是最普遍的问题，该文从各方面的影响因素就这个问题进行探讨。工艺参数的控制：茶叶含量在0．6％－0．7％之间时，饮用效果最好。浸提时间10min效果最好，浸提温度80－90℃可达到极高革取率及充足色泽。增加茶计PH度，茶乳生成量下降，空气量在加工中要尽量除去。外助的控制：使用某种添加剂，以最终达到减少条乳的目的。第一灯是促进茶乳迅速或完全沉淀后除去，如添加某些离子，如钙，它可与茶中的多元酚类形成Poyhend－cafe1unscomplex促进茶乳生成，进而达到分离效果；加酸降低PH值（…     

茶汁膜分离浓缩工艺与热蒸发浓缩工艺的比较研究

采用蒸发 (EC)、超滤 +反渗透 (UF +RO)、超滤 +蒸发 (UF +EC)、反渗透 (RO)浓缩工艺分别进行绿茶、红茶、乌龙茶汁的浓缩试验 ,并对各个样品的主要化学成份进行分析。结果表明 :四种工艺对三种茶浓缩汁中主要的化学成分保留率及感官品质的影响明显不同。UF +RO和RO浓缩工艺保留主要的化学成分及香味品质最佳 ;UF +RO和UF +EC工艺从茶汁中去除蛋白质和果胶的效果及茶汁的澄清度最佳 ;因此UF +RO浓缩工艺是四种浓缩工艺中的最佳工艺     

不同保鲜剂对碧螺春茶保鲜效果的研究

以苏州碧螺春茶为原料，设计了16种不同保鲜剂，经过一定条件贮藏老化后，考察它们对碧螺春茶的保鲜效果。结果表明：处理9(硅胶和抗坏血酸钠系列)及处理11(焦亚硫酸钠和抗坏血酸钠系列)保鲜效果最好；处理1(铁粉和氯化钠系列)、处理6(铁粉、氯化亚铁、碳酸氢钠、反丁烯二酸和沸石系列)、处理12(细孔硅胶)、处理14(活性干燥剂)保鲜效果较好，并对感官品质各特点与生化成分含量的相关性做了分析研究     

茶树花冰茶的研制

以茶树干茶花为原料,通过浸提试验和3因素3水平正交试验确定茶树花汁的最佳浸提条件和茶树花冰茶的最佳配方。结果显示,当固液比为1：60时,茶树花汁中茶多酚含量最高。低温萃取时,茶树花汁呈透明的土褐色,冷却后也不易产生冷后浑的现象,而高温萃取时茶树花汁颜色较深且有沉淀产生。茶树花汁的最佳浸提条件为：固液比1：60,浸提温度80℃,浸提时间5min;用茶树花汁配制茶树花冰茶的最佳配方为：     

琯溪蜜柚柚瓣的臭氧处理结合气调包装保鲜研究

采用正交试验设计，优选出最佳的臭氧处理时间和气体成分，分析了臭氧处理结合气调包装（MAP）保鲜对琯溪蜜柚柚瓣品质的影响。结果表明：臭氧处理结合气调包装的方法可明显延长琯溪蜜柚柚瓣的保鲜时间，改善保鲜柚瓣的品质，臭氧处理5min，以5％O2、3％CO2、92％N2的气体成分包装的保鲜效果最好。     

瓶装绿茶水的试制初报

本文采用七因素二水平组合试验，对瓶装绿茶水制作进行研究，结果表明：ＳＳ剂用量、水质、茶水比及乙醇沉淀法四因素达到极显著差异。ＳＳ剂作为转溶剂，具有抑制茶多酚及其氧化产物被进一步氧化综合，防止茶汁颜色转暗的作用；蒸馏水对避免绿茶水混浊、沉淀有显著的效果；采用乙醇沉淀法，消除绿茶水在贮藏沉淀的形成有一定作用，但在添加ＳＳ剂的情况下以不用为好；维生素Ｃ起到抗氧化作用，使茶多酚免受氧化，对茶水色泽起到极好     

茶香啫喱糖生产技术

以茶叶(红茶或绿茶)为原料，采用热水重复浸提法提取茶汁，再经真空浓缩成茶汁浓缩物，并配以白砂糖、淀粉糖浆等甜味剂就可生产出茶香浓郁、营养丰富、富有弹性、组织软韧、耐嚼、甜度低的新型软糖——茶香啫喱糖。其特点是设备投资少、工艺简单、产品质量好、有利于保持茶汁中香味成分。     

3种澄清剂对香蕉汁的澄清效果

以完全黄熟的香蕉为原料，研究明胶-单宁、交联聚乙烯吡咯烷酮(PVPP)和壳聚糖3种不同澄清剂对经过果胶酶初步处理后的香蕉汁澄清效果的影响。结果表明：3种澄清剂对香蕉汁中的可溶性固形物浓度影响差异很小；3种澄清剂对香蕉汁澄清效果的影响为壳聚糖处理效果最好，其次是聚乙烯吡咯烷酮，明胶-单宁效果最差；在香蕉汁中添加0.30 g/L的壳聚糖B，40 ℃下静置10 h后，可得到透光率为95%以上、清澈透明的香蕉汁。     

Water transfer from agriculture to urban uses: lessons learned, with policy considerations

This paper sets forth the accomplishments to date of the international collaborative study program on efficient and equitable transfer of water from agriculture to other uses. The research consists of several components. First a bibliographical review was prepared of literature available on the practice of inter-sector water transfer. Second, nine case studies have been prepared that illustrate inter-sector water transfer under a variety of physical and economic and political environments. Third, a framework has been developed for characterizing and comparing water transfer options and compensation among case studies. We discuss the pricing of irrigation water in determining compensation. We develop a decision tree that traces the paths to the various sector water transfer options. Finally, we discuss water transfer policy options with specific reference to Taiwan, though they have more general relevance. Three options are identified which reflect different objectives for government intervention.     

Water markets as a mechanism for intersectoral water transfers: the Elqui Basin in Chile

The Elqui River in north-central Chile provides water for a medium-sized urban area and a small but thriving irrigated agriculture sector. A number of factors combined to provide incentive for the municipal water company servicing the coastal urban area to purchase water-use rights from irrigators in the early 1990s. This transfer was a well-recorded example of Chilean water markets functioning as proponents had expected. And despite the elapsed time, and Chile’s favorable system of transferable water-use rights, these trades remain among the very few recorded cases of intersectoral trading in the country. By purchasing water rights this water supply company was able to reduce its cost of raw water provision. Economic analysis of this transfer showed relatively modest economic gains from trade. Although, the value of water in municipal water supply is high, the value of water to profitable farmers is also high. The construction of the Puclaro Dam on the Elqui River demonstrates that the intersectoral water transfer that occurred in the early 1990s will not be the ultimate solution to the urban water supply needs of this urban area.     

The Lower Rio Grande Valley: a case study of a water market area

The Lower Rio Grande Valley is a sub-tropical area with a productive irrigated agriculture, but with an over-committed single water resource. It is experiencing a rapidly growing population that is placing increasing pressure on the water resource. This, combined with expanding urban areas and land moving out of agriculture, has resulted in a vigorous water market, with transfers from agriculture to municipal uses. For the US portion of the valley, transfers from agriculture to municipalities are either short-term (usually 1 year) or permanent. Prices vary depending upon the location and timing, and result from negotiations between the parties. Over time, and not without difficulty, the water market has been facilitated by appropriate enabling legislation, water rights that have been validated judicially, and an efficient transfer mechanism that has a minimum of transaction cost. Government involvement is primarily for protection of the public, and to facilitate the transfer process.

Chlorophyll meter-based nitrogen management of rice grown under alternate wetting and drying irrigation

Farmers have adopted alternate wetting and drying (AWD) irrigation to cope with water scarcity in rice production. This practice shifts rice land away from being continuously anaerobic to being partly aerobic, thus affecting nutrient availability to the rice plant, and requiring some adjustment in nutrient management. The use of a chlorophyll meter (also known as a SPAD meter) has been proven effective in increasing nitrogen-use efficiency (NUE) in continuously flooded (CF) rice, but its use has not been investigated under AWD irrigation. This study aimed at testing the hypotheses that (i) SPAD-based N management can be applied to AWD in the same way it is used in CF rice, and (ii) combining chlorophyll meter-based nitrogen management and AWD can enhance NUE, save water, and maintain high rice yield. Experiments were conducted in a split-plot design with four replications in the 2004 and 2005 dry seasons (DS) at IRRI. The main plots were three water treatments: CF, AWD that involved irrigation application when the soil dried to soil water potential at 15-cm depth of −20 kPa (AWD₋₂₀) and −80 kPa (AWD₋₈₀) in 2004, and AWD₋₁₀ and AWD₋₅₀ were used in 2005. The subplots were five N management treatments: zero N (N₀), 180 kg N ha⁻¹ in four splits (N₁₈₀), and three SPAD-based N-management treatments in which N was applied when the SPAD reading of the youngest fully extended leaf was less than or equaled 35 (N_SPAD35), 38 (N_SPAD38), and 41 (N_SPAD41). In 2005, N_SPAD32 was tested instead of N_SPAD41. A good correlation between leaf N content per unit leaf area and the SPAD reading was observed for all water treatments, suggesting that the SPAD reading can be used to estimate leaf N of rice grown under AWD in a way similar to that under CF. SPAD readings and leaf color chart (LCC) values also showed a good correlation. There were no water × nitrogen interactive effects on rice yield, water input, water productivity, and N-use efficiency. Rice yield in AWD₋₁₀ was similar to those of CF; yields of other AWD treatments were significantly lower than those of CF. AWD₋₁₀ reduced irrigation water input by 20% and significantly increased water productivity compared with CF. The apparent nitrogen recovery and agronomic N-use efficiency (ANUE) of AWD₋₁₀ and AWD₋₂₀ were similar to those of CF. The ANUE of N_SPAD38 and N_SPAD35 was consistently higher than that of N₁₈₀ in all water treatments. N_SPAD38 consistently gave yield similar to that of N₁₈₀ in all water treatments, while yield of N_SPAD35 about 90% of that of CF. We conclude that a combination of AWD₋₁₀ and SPAD-based N management, using critical value 38, can save irrigation water and N fertilizer while maintaining high yield as in CF conditions with fixed time and rate of nitrogen application of 180 kg ha⁻¹. Treatments AWD₋₂₀ and N_SPAD35 may be accepted by farmers when water and N fertilizer are scarce and costly. The findings also suggested LCC can also be a practical tool for N-fertilizer management of rice grown under AWD, but this needs further field validation.     

The development and management policy of water resources in Taiwan

Taiwan is a small island located in monsoon Asia with an annual precipitation exceeding 2,500 mm, which is 2.6 times the world average. However, water available for each person in Taiwan is less than one seventh of the world average due to Taiwan's crowded population and river basin characteristics. Steep land slope and uneven time and space distribution of rainfall have caused water resources problems. Providing a pure and plentiful supply of water for the people challenges the Water Resources Agency in Taiwan. History is a powerful tool for portraying the future. This paper discusses major themes in the review of water resources development over the last centuries. The changes in social-economic development, water resources infrastructure and demands of water are central to the discussion, with an eye to the plentiful and sustainable implications of water resources management in Taiwan. The water policy in the twenty-first century is also outlined.Dr. Hwang is the Advice of the Council for Economic Planning and Development (CEPD), Ministry of Economic Affairs (MOEA), Taiwan, Chairman of the Water Resources Committee, Chinese Institute of Civil and Hydraulic Engineering, a board member of the International Commission on Irrigation and Drainage (ICID) Chinese Taipei Committee, former chairman of the Chinese Society of Agriculture Engineering (CSAE), former director of Water Resources Agency (WRA), former director of the Taiwan Provincial Water Conservancy Agency (TPWCA), and former director of the Taiwan Provincial Water Conservancy Bureau (TPWCB).     

A viewpoint to apply water pricing to the Asian humid tropics

The OECD has introduced a water pricing mechanism and listed eight categories gleaned from experience in OECD countries. However, in the Asian humid tropics, it is too early to apply water pricing because there is seldom a concept of water right, or practical organization of water management. In almost all irrigation projects in Japan, area charge has been applied, and collected fees have recovered entire operation and maintenance costs. Although effective volumetric charge is employed in several regions in Japan, most farmers pay area-based annual charges at several times of the year via Land Improvement Districts. In the Asian humid tropics, it is important to facilitate the establishment of sound management organizations of irrigation water before introducing a strict water pricing mechanism to levy the charge.     

Assessment of irrigation efficiencies and water productivity in paddy fields in the lower Mekong River Basin

Improving irrigation performance is a crucial issue for agriculture and irrigation development in the Lower Mekong River Basin to secure food production for people’s livelihoods. Irrigation efficiency is the most important indicator to determine the performance of an irrigation scheme. This study looks at water management practices and irrigation efficiency in three pilot sites in the Lower Mekong River Basin: the Numhoum scheme in Laos, the Huay Luang scheme in Thailand, and the Komping Pouy scheme in Cambodia. Irrigation efficiency and water productivity were analyzed using a water balance approach at the irrigation scheme level and results in the pilot areas show efficiencies that are definitely higher using this approach than by using the classical concept. Lower water productivity was observed at pilot schemes in areas of single cropping and higher productivity in areas where multiple agricultural activities were practiced. Strict and active water management is required to control and save water to meet agricultural demand and have sufficient water to expand cultivation areas while avoiding shortages. Promoting multiple uses of water for various agricultural activities in command area will increase water productivity.

水稻节水栽培研究进展

总结了国内外水稻耐旱品种选育、水稻节水灌溉技术、覆盖旱作技术以及稻田土壤耕作技术等主要水稻节水栽培技术,并对水稻节水栽培技术的研究方向进行了展望。     

水分胁迫对水稻生长的影响

通过不同时期、不同程度水分胁迫对水稻生态、生理、生化指标及生育状况影响进行试验研究,针对辽河中下游平原水稻生产,提出了不同湿润年的水分生产函数及相应的敏感指数;提出了非充分灌溉条件下的调优灌溉栽培技术。     

Farm level practices and water productivity in Zhanghe Irrigation System

China, the biggest rice-producing country in the world, has put considerable effort into finding ways to conserve water in rice cultivation. One very promising practice, intermittent submerged irrigation (ISI) was reported to be applied on farmers fields over a large area in the Zhanghe irrigation system (ZIS), which serves about 160,000 ha of irrigated land, which is intensively cultivated with rice. To better understand the actual farmer practices, the degree to which farmers adopt ISI, the resulting water productivity, and implications for farm and system water management, a water accounting methodology developed by IWMI was applied at farm and a larger meso scale. Two areas were observed: Tuanlin, where ISI was reported to be widespread (with ISI), and Wenjiaxiang, where farmers were reportedly not adopting ISI (without ISI). The field water level measurements demonstrate that farmers at the with ISI site follow a practice similar to the theoretical ISI techniques by letting ponding levels drop to the soil surface several times during the cropping season. At the without site, farmers keep higher water levels ponded, and do not let water levels drop to the soil surface as often as the with site. A major determinant of practice is ease of access to water. At the with site, farmers have access to a variety of sources such as ponds and drains. At the without site, access to water was primarily from canal water, without the degree of flexibility as areas that had a water source near the field. The process fraction of gross inflow at field scale (rice evapotranspiration divided by irrigation plus rain) ranged between 0.66 and 0.93, remarkably high values showing how effective farmers are in converting water sources to productive evapotranspiration. The on-farm water accounting results show that with ISI, the average values of irrigation water applied over two years 1999–2000 are 22% less than without ISI, and the yields approximately the same. The resulting water productivity values per unit of irrigation water (WP_irrigation) are 20% higher under ISI practices, but per unit of evapotranspiration water productivity results are similar. The meso site study yielded surprising insights into overall water management in the area. In the years 1999 and 2000, at the meso sites, the irrigation duty in Tuanlin (with ISI) was 29% and 21% less than in Wenjiaxiang (without ISI), respectively, resulting in WP_irrigation values of 24% and 26% higher at Tuanlin than Wenjiaxiang. But values of process fraction of gross inflow were considerably reduced at the meso scale ranging between 0.12 and 0.29, with considerable drainage outflow observed. Different land uses, trees, roads, villages, and ponds, begin to play an important role in overall water resource management at this scale. Drainage water from fields plus runoff served as supplies to ponds within the meso area as well as downstream reservoirs. Ponds play a very important role as an additional source of water, and in fact facilitate the uptake of ISI practices. This demonstrates that there are multiple strategies at play influencing water savings and productivity beyond ISI in the management of water within the area.