广东省主要农产品消费需求现状、趋势与对策

近年来,广东省主要农产品消费需求呈现新特征,主要农产品消费量走势各异,水稻与蔬菜的消费量平稳波动,食用油、肉类、水果和水产品消费总量均呈现不同程度的增长趋势。从消费结构角度看,城乡农产品消费结构存在较大差异,比如稻米、蔬菜城镇人均消费趋稳,农村居民消费开始下降。消费结构的转变导致了广东省主要农产品进出口情况转变,目前广东主要农产品进出口呈逆差状态,大部分小麦等粮食需从外省调入。采用GM(1,1)模型对广东主要农产品消费做出需求预测,发现未来10年的稻谷、蔬菜、食油、肉类、水果和水产品的消费需求均呈现平缓增加的趋势,并根据上述预测结果做出相应的政策建议。     

日本茶叶市场概况

日本是世界第5大茶叶消费国,虽然其绿茶消费量约占全国茶叶消费量的75％,但近年来对红茶及乌龙茶显示出持续旺盛的需求。日本绿茶消费主要通过国内生产供应,而红茶和乌龙茶则主要依赖于进口。日本每年的茶叶消费量达1．5亿kg,以绿茶、红茶和乌龙茶为主;此外,还消费相当数量的速溶茶,2004年,进口速溶茶200万kg,但是到2005年底下降到150万kg,2006年底持续下降到100万kg。     

国内外天然橡胶产供销分析及其趋势预测

分析全球天然橡胶的生产、进出口贸易、消费和库存情况，对未来天然橡胶产量、消费量和价格进行估计；并预测和展望今后全球天然橡胶的供求情况。     

世界棉花生产和消费概况

最近几年(1979～1983年)世界棉花的生产和消费,进出口贸易变化不大;在纺织原料价格增长不大的情况下,国家棉花市场贸易处于稳定,棉花消费量只稍微有些增长。许多国家棉花播种面积缩减,棉花价格提高,是由于世界棉花生产国家能源紧张和原料危机引起的。世界棉花生产水平,以1981/82年度为最高,皮棉总产量比1980/81年度增加13％,棉花播种面积只增加1％,主要是棉花单位面积产量提高。从表1资料可见,美国这几年皮棉产量由242.8万吨,增加到340.6万     

食糖消费知多少

食糖消费量与人们的食物结构有联系,一般说来,以谷物为主的地区食糖消费相对少些,也与生活习惯有关。印度年产糖(包括土糖)1000～1500万吨,基本上全是本国人消费,而我国一年只消费750万吨左右。食糖消费与生活水平有更大关系:生活水平愈高食糖消费量愈大。发达国家的人均食糖消费量为世界平均量的2倍还多。60年代,我国人均消费食糖仅2公斤,70年代为4公     

英国的茶叶贸易与饮茶文化

英国是西方世界茶叶贸易与消费的典型代表。本文引用近40年来英国茶叶进口、转口和消费数据,阐述英国茶叶进出口贸易和国内市场流通现状、变化趋势。百余年来茶叶进口来源的二次大转移。伦敦茶叶拍卖市场的衰退,被产地市场取代的原因。英式传统饮茶文化及近年受到的冲击。以及三百年来中英茶叶贸易的变迁,和复兴贸易须改进的方向。     

东镇县上莞镇茶叶发展现状调研

广东省是茶叶生产和消费大省，据统计2007年的茶叶产量为4．5万t，以绿茶和乌龙茶为主；年消费量超过10万t：主要茶叶产区集中在潮州、梅州、河源、韶关、清远以及湛江等市。     

世界花生的贸易格局分析

世界花生的生产和出口比较集中,中国、美国、阿根廷和印度既是主产国也是主要的花生出口国。各个主要花生出口国的花生出口价格差异较大。中国是世界花生的最大出口国,研究世界花生的进出口贸易格局,有利于了解我国花生出口面临的国际市场环境。     

欧洲茶叶市场及对中国茶叶出口的启示

欧洲是世界上主要的茶叶消费区域之一,目前大多数欧洲市场仍以消费红茶为主。随着人们对健康的重视,欧洲茶叶市场呈现一些新的趋势,终端消费市场上,欧洲消费者对饮茶有益健康的意识增强,茶叶消费呈现品质化、多样化和便利化趋势,相应地,对茶叶贸易的可追溯和可持续的需求增加,相关认证日益重要。     

大麦品质育种研究进展

大麦籽粒的品质是决定其食用价值、饲用价值和酿造产品质量的主要因素。过去,大麦主要用于食用或喂饲牲口。随着啤酒工业的发展,大麦逐步转化为工业原料,对大麦品质提出了新的要求。世界各大麦生产国针对不同用途大麦品种的品质要求,积极开展专用大麦的品质育种研究以及相关理论和方法的研究,取得显著进展,本文从不同用途大麦的品质要求、品质育种、品质遗传和品质分析四个方面概述大麦育种的主要研究进展。     

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.     

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.     

Evolutionary aspects of the trade-off between seed size and number in crops

Whereas the concept that availability of resources drives seed production is sound in principle, it is incomplete as there are many solutions to the allocation of resources that derive from the trade-off between number and size. This paper examines evolutionary aspects of this trade-off in annual grain crops. The analysis is centred on the working hypotheses that, for a given species and environment, allocation of resources to reproduction involves (H1) high plasticity in seed number, which allows for variable resource availability, and (H2) a relatively narrow range of seed size that results from evolutionary and agronomic selection. Comparisons between crops and fish are used to highlight common evolutionary elements in taxa where parents provide little or no care to their offspring, with the consequence that both number and early survival of offspring, hence fitness of parents, are partially related to embryo size and reserves.

The plasticity of seed number in relation to availability of resources is analysed against the established relationship between offspring number and parent growth rate during critical stages. The notion that seed size is under stabilising selection is analysed against three conditions: (1) mean seed size is conservative for a given species and environment, (2) seed size affects fitness, and (3) seed size is heritable. Databases from published papers were compiled to analyse the relative variability of seed size and number, and the heritability of seed size. Evidence for and against the link between seed size and parental fitness is revised using the Smith–Fretwell model as framework (Am. Nat., 108, 499–506).

The proposal of high plasticity of seed number and narrow variability of seed size resulting from stabilising natural selection is generally consistent with evolutionary and genetic considerations. Agronomic selection may have reinforced natural selection leading to relatively narrow seed size in species such as wheat and soybean, where cultivated types retained high plasticity for seed number. In contrast, selection for one or few inflorescences in crops like sunflower and maize may have morphologically reduced seed number plasticity and increased variability of seed size and its responsiveness to resource availability in relation to their wild ancestors.     

Citrus Flavonoids in Fruit and Traditional Chinese Medicinal Food Ingredients in China

Flavonoids-enriched tissues of citrus such as peel, immature fruit and flower are consumed as culinary seasonings, tea ingredients in China for centuries. This HPLC quantitative study on the five citrus flavonoids, naringin, hesperidin, neohesperidin, sinensetin and nobiletin on a wide range of Chinese citrus fruits and several Traditional Chinese Medicinal food ingredients in East China, revealed a great diversity in flavonoid composition. Huyou peel (C. paradisi cv. Changshanhuyou) was found to be the best naringin (3.25%) and neohesperidin (2.76%) source; C. aurantium, a major ingredient of several citrus-related TCM, is also a suitable source of naringin and neohesperidin, and a good juice source for flavanone glycosides; the peel of Wenzhoumiju (C. unshiu) is one of the richest local species in hesperidin (up to 6.25%); Zaoju (C. subcompressa) has the highest content of nobiletin (0.59%), a polymethoxylated flavone. LC-ES-MS analysis of Zanthoxylum genus for flavonoids revealed for the first time the presence of significant amounts (0.74%) of hesperidin in the root of Liangmianzhen (Z. nitidum (Roxb.) DC), a relative of Sichuan pepper, which is a spice widely used in China.     

Effect of a continuous hot water treatment of potato tubers on seed-borne fungal pathogens

Summary The viability of five pathogens was decreased by treatment with hot water when tested in vitro.Polyscytalum pustulans was most sensitive andRhizoctonia solani least sensitive. Potato tubers were exposed to 55°C for 5 min in a commercial continuous hot water treatment plant using naturally contaminated seed tubers and tubers which had been inoculated by dipping in comminuted cultures. The frequency of eyes colonised byP. pustulans, Helminthosporium solani, andR. solani was reduced to virtually zero and the effect persisted on tubers subsequently stored at 4°C and at 15°C for up to 16 wk. Results withColletotrichum coccodes were inconclusive. Treatment suppressedPenicillium spp. which, however, rapidly recolonised the eyes during storage, leading to higher contamination levels in the treated than in the untreated tubers. With tubers inoculated withPhoma foveata, good control was achieved when the incubation period before treatment was 10 d but not when the period was 42 d.     

Role of Benzoxazinones in Cereals

Summary

Heterocyclic 1,4-benzoxazin-3-ones and related benzox-azolinones are important natural products of the cereal crops maize, wheat and rye. Much research has focused on the role of these compounds as defensive agents against plant diseases and pests. Studies of a wide variety of biological effects on herbivores and nematodes, plant pathogenic fungi and bacteria are reviewed in this article. Phytotoxic activity of the compounds is also considered with respect to allelopathic interaction with higher plants. Recent investigations of molecular aspects of interactions of cyclic hydroxamic acids and related benzoxazo-linones with acceptor organisms have demonstrated different effective detoxification strategies and tolerance mechanisms. This research has greatly advanced our knowledge about the multiple roles that these allelochemicals play in ecological systems.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part I: Influence of ultra-fine grinding

Wheat bran is an undervalued by-product of white flour and has great nutritional potential due to its high content in fibres and bioactive compounds. Micronized bran could be used as a food ingredient to improve the nutritional potential of cereal products, or be used as a starting material for other processes (bioactive compound extraction or bran fractionation). The aim of this work was to find a way to efficiently decrease the particle size of bran. The influence of the grinding temperature (ambient or cryogenic grinding) on the granulometric distribution of particles, their composition, and their microstructure was studied, at lab-scale and pilot-scale. It showed that the intrinsic characteristics of bran (glass transition within intermediate layers at −46 °C) had more influence on its grinding behaviour than the type of grinding device used: the particles size distributions obtained after grinding at lab-scale and pilot-scale were very similar. At both scales, the granulometric curves were narrow for cryogenic grinding, while for ambient grinding they were spread over the whole particle size range. Ultrafine particles were obtained in both ambient and cryogenic conditions. Negative temperatures, by increasing the material’s brittleness, favoured a fast fragmentation of bran: one step of cryogenic grinding allowed a median particle size of nearly 50 μm to be reached, whereas three successive steps of ambient grinding were needed for the same result. On the other hand, ambient temperature favoured the dissociation of the different constituent layers of wheat bran, and produced less composite particles than cryogenic grinding.     

Multiple use of plants: Studies on selenium incorporation in some agricultural species for the production of organic selenium compounds

The technique of spraying plants with inorganic forms of selenium can be employed for phytochemical production of organic selenium compounds. Fractionation of the plant material makes it possible to produce a highly concentrated and well defined selenium supplement with potential use in animal and human nutrition. The fractionation also gives opportunities to combine production of organic selenium compounds with other products, for example plant fibres. Multiple use of plants can contribute to a more efficient utilization of land area (in comparison to monocultures solely adapted to food production). It also gives the opportunity to develop systems suitable for long term fixation of carbon, as long as the plant material is not reoxidised to carbon dioxide. Plant fibres could provide raw material for the production of paper or building materials in combination with the production of organic selenium compounds preferentially accumulated in another fraction of the processed plant.     

Biological factors influencing the transmission of potato leafroll virus by different aphid species

Summary Macrosiphum euphorbiae, collected in the field from potato plants infected with potato leafroll virus (PLRV), transmitted the virus to fewer potato plants in a field trial than did laboratory-rearedMyzus persicae. In the laboratory,M. persicae was the only efficient vector of PLRV fromPhysalis floridana seedlings, potato sprouts or excised leaves toP. floridana. Two clones ofM. euphorbiae and one clone ofAulacorthum solani transmitted PLRV from infected potato plants toNicotiana clevelandii as effeciently asM. persicae but a clone ofAphis gossypii was an inefficient PLRV vector. An isolate of PLRV, whichM. persicae transmitted inefficiently from potato toN. clevelandii, was also transmitted inefficiently byM. euphorbiae andA. solani.