苦丁茶酶解浸提方法的研究

通过添加外源酶（纤维素酶、果胶酶和木瓜蛋白酶）浸提苦丁茶,分析了苦丁茶浸提液中化学成分含量的变化,以及单一酶和酶组合间的比较分析,得出苦丁茶的最适酶解浸提方法为时间40βmin、温度50℃、pH值5.5和纤维素酶浓度0.2％。     

仙草多糖提取工艺条件优化研究

采用水提法浸提仙草，以仙草多糖的提取率为指标，研究料液比、浸提温度、浸提时间及浸提次数4个因素对其提取率的影响，并从中挑取合适的因素水平进行正交试验及SPSS分析。结果表明：在这4个因素中，对提取率影响最大的因素是浸提温度，然后是浸提时间，再次是料液比，最后是浸提次数；在料液比1:60、温度100 ℃、浸提时间3 h的最优条件下，仙草多糖的提取率高达17.89 %，此时仙草多糖的含量为44.13 %。     

食用菌浸提工艺及其复合饮料的研究

以多糖浸出量为指标,进行银耳、竹荪、香菇、姬松茸的浸提工艺优化,获得最佳浸提工艺参数为:银耳浸提料水比1∶100,温度90℃,浸提时间3 h;竹荪浸提料水比1∶110,温度100℃,浸提时间3 h;香菇浸提料水比1∶80,温度100℃,浸提时间3 h;姬松茸浸提料水比1∶100,温度100℃,浸提时间3 h.经复合饮料...     

普洱茶中α-淀粉酶抑制剂的提取工艺研究

本文研究了普洱茶中α-淀粉酶抑制剂的提取工艺。以水为溶剂，选取浸提时间、固液比和浸提温度三个因素做单因素实验，然后通过正交实验方法确定最佳提取工艺。结果表明，普洱茶中α-淀粉酶抑制剂的最佳提取工艺条件为浸提时间为1h，固液比1：20，温度为93．5℃。经反复实验，结果稳定，此工艺可为进一步研究普洱茶淀粉酶抑制剂及深入开发利用普洱茶提供一定的理论依据。     

‘红仙蜜’火龙果果皮红色素的提取工艺研究

采用水浴浸提火龙果果皮红色素,通过单因素和正交试验研究浸提液乙醇浓度、pH值、水提温度和水提时间对火龙果果皮红色素提取效果的影响。结果表明,影响火龙果果皮红色素提取的主要因素及次序为:浸提温度、提取液浓度、pH值、浸提时间。试验范围内,火龙果果皮红色素最佳提取工艺条件为:浸提温度30℃、浸提时间45 min、pH值为6.5和乙醇浓度40%。     

普洱茶主要氧化产物提取条件的优化及其抗氧化活性分析

以普洱茶为原料,研究溶剂pH值、浸提温度、时间、料液比对茶褐素（TBS）提取率的影响。结果表明,溶剂pH值、浸提温度、时间、料液比等都显著影响TBS的浸提效果,其中料液比、浸提温度、浸提时问达到了极显著水平,各因素影响效果的重要眭依次为：料液比〉浸提温度〉浸提时间〉溶剂pH值。同时得到茶褐素浸提的优化条件为：温度100℃,溶剂pH=7,料液比1：30,时间20min。茶褐素抗氧化活性分析结果显示,其抗氧化活性优于普洱茶水提物。     

正交设计法研究花生粗脂肪含量测定方法

以石油醚为浸提剂,选择浸提温度、浸提时间和淋洗时间3个因素,根据L9(34)正交设计表,用FOSS2050型脂肪测定仪对索氏提取法测定花生粗脂肪含量进行了研究。结果表明,淋洗时间对花生粗脂肪含量测定结果影响最大,其次是浸提时间;花生粗脂肪含量测定的最佳提取方案为浸提温度120℃、浸提时间80 min、淋洗时间30 min。     

茶饮料浸提工艺参数的研究

通过对绿茶饮料制造过程中浸提工艺参数的研究发现，浸提温度（T）、浸提时间（t）及茶叶浓度（C）不同程度地影响成品的滋味、色泽、香气。利用正交实验法得到当T为90℃，t为3min，C为1.5％时，产品的感观品质最佳，验证实验进一步证明了上述结论。茶饮料浸提工艺参数的研究@于敏     

利用固定化纤维素酶酶解夏季绿茶工艺的研究

以壳聚糖作为载体,戊二醛为交联剂制备固定化纤维素酶,对夏季绿茶进行酶解。通过正交实验得到优化工艺：在1.0g茶叶中,以茶水比1︰20,加入1.0g固定化纤维素酶,55℃下恒温浸提50min。与传统高温水提法所得茶汤相比,以此工艺条件浸提所得茶汤中茶多酚、氨基酸、咖啡碱含量有所提高,酚氨比有所下降,连续提取7批次茶叶,固定化纤维素酶的相对酶活力仍保持80%以上。     

基于熵权法的响应面优化罗望子果肉活性物质酶法浸提工艺

为优化罗望子果肉浸提工艺,提供罗望子果肉加工与罗望子果肉活性物质研究的理论依据。本研究以多糖提取率、原料利用率、总酚提取率和总黄酮提取率为响应值,以熵权法赋权,通过响应面法对罗望子果肉纤维素酶法浸提工艺进行优化,并对其浸提过程中浸提液的抗氧化活性变化进行了研究。结果发现罗望子浸提液对于OH?清除能力极强,均大于190 mg/100 mL,OH?清除能力和ABTS ⁺?清除能力对提取条件的变化敏感。考虑实际情况得到最佳提取工艺的提取时间为51 min,料液比为1:10.9（g/mL）,纤维素酶添加量为质量比1.5‰,在此条件下,罗望子果肉多糖提取率为12.66%,原料利用率为88.24%,总酚提取率为4.79‰,总黄酮提取率为4.38‰,与理论预测值接近。该模型能较好预测罗望子果肉的浸提工艺,可以用于保健饮料加工。     

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.