福建参薯类山药资源尿囊素含量的测定比较

运用高效液相色谱法测定福建参薯类山药资源的尿囊素含量，以检测比较不同参薯类山药资源的尿囊素含量。结果表明：在相同栽培条件下，不同产地山药的尿囊素含量存在一定的差异；采用YMC ODS-AQ色谱柱，尿囊素在0.3～2.1 μg间线性关系良好，回收率为96.4%(RSD＝2.4%)，精密度良好(RSD＝1.2%)，样品提取液在10 h内稳定(RSD＝2.0%)。该方法简便可靠，可作为山药质量控制的检测手段之一。     

超高效液相色谱-质谱/质谱法同时测定蔬菜中7种磺胺的残留量

为建立超高效液相色谱-质谱/质谱法(UPLC-MS/MS)同时测定蔬菜中7种磺胺残留量的方法。样品用1%乙酸乙腈提取，以C18色谱柱分离待测物，采用多反应监测(MRM)离子扫描模式，外标法进行定量，线性良好，相关系数均大于0.999。结果显示：7种磺胺的检出限为0.000 4～0.000 6 mg/kg，样品添加回收率为67.5%～94.1%，相对标准偏差均少于5.3%(n＝6)。该方法简单快捷、定量准确，可满足多种蔬菜中7种磺胺的残留检测要求。     

超快速高效液相色谱法测定普通白菜中16种氨基甲酸酯类农药残留

研究应用超快速高效液相色谱仪柱后衍生荧光检测器同时测定普通白菜中16种氨基甲酸酯类农药残留。对流动相组成、波长选择、梯度洗脱等条件进行比较研究,建立了样品经乙腈提取,SPE-NH2固相萃取柱净化,液相色谱柱后衍生分离,荧光检测(λex＝339 nm, λem＝445 nm)测定,外标法定量的检测方法。研究表明：基于液相色谱荧光检测条件,16种农药残留在0.025～1.0 mg/L浓度范围内线性关系良好;检出限0.002～0.010 mg/L;平均加标回收率73.0%～103.0%,相对标准偏差(RSD)1.5%～8.8%。该研究确定的方法具有检测范围广、快速、灵敏、准确、重现性好、易推广等特点。     

一种安全简便测定椰子胚乳乙酰辅酶A羧化酶活性的方法

建立利用HPLC测定椰子胚乳乙酰辅酶A羧化酶(ACCase)活性的方法。色谱柱为德国MN nucleosil C18(4.60 mm i.d×250 mm,5.0 μm),流动相为10 mmol/L 磷酸二氢钾(pH 6.7)︰甲醇＝90︰10(V︰V)。结果表明：Malonyl-CoA浓度在0.02～0.12 μg/mL,色谱方法有良好的线性关系,线性相关系数为0.999,Malonyl-CoA最低检测浓度为0.02 μg/mL,最终测定椰子胚乳ACCase活性为1.20 ng Malonyl-CoA/min/μg酶蛋白。     

高效液相色谱测定木薯块根β-胡萝卜素的方法优化

为确定高效液相色谱法测定木薯β-胡萝卜素的最佳方法,以丙酮/石油醚(2/5,V/V)为提取液,甲醇/叔丁基甲醚(70/30,V/V)为流动相,对白心木薯SC101和蛋黄木薯SC9块根β-胡萝卜素保留时间及其分离情况进行研究。检测条件为：色谱柱YCM C30,柱温30℃,流速为1 mL/min等度洗脱。结果显示：该方法精确度和重复性的变异系数均小于5%,保留时间为12.65 min,在2～30 μg/mL浓度范围内线性关系良好(y= 209.11x－14.114,R2＝0.9993);平均回收率为81%～92 %。采用改进的HPLC法对木薯块根β-胡萝卜素进行测定,数据稳定性好,分析时间比已报道的方法缩短30 min以上,适用于快速定量分析木薯块根的微量β-胡萝卜素含量。     

罂粟植株不同部位吗啡含量测试

采用HPLC法测定罂粟茎、叶、壳部位中吗啡的含量，其色谱条件为：色谱柱HypersillC18(5 μm，4.6 nm×250 nm)；流动相：磷酸二氢钾(0.05 mol/L):庚烷磺酸钠(0.002 5 mol/L):乙腈=(5:5:2)；检测波长220 nm。结果显示：罂粟植株中吗啡含量依次为：壳>叶>茎>；罂粟壳中吗啡的含量为2.567 %-3.455 %，叶中含量为1.742 %-2.653 %，茎杆中含量为0.128 %-0.467 %。     

分散固相萃取-反相高效液相色谱法测定蔬菜、水果中10种氨基甲酸酯类农药残留

建立分散固相萃取-反相高效液相色谱同时测定蔬菜和水果中10种氨基甲酸酯类农药(涕灭威，涕灭威砜，涕灭威亚砜，克百威，3-羟基克百威，灭多威，甲萘威，异丙威，速灭威，仲丁威)残留的分析方法。样品经乙腈提取，PSA分散固相萃取净化，液相色谱柱后衍生分离，荧光检测(λex＝330 nm, λem＝465 nm)测定，外标法定量。10种农药在0.005～0.50 mg/L范围内线性关系良好；检出限在0.004～0.008 mg/L；平均加标回收率在75.6%～112.3%，相对标准偏差(RSD)在 0.8%～10.2%。该方法具有快速、灵敏、准确、重现性好以及操作简单等特点，适合日常大批量蔬菜和水果样品中10种氨基甲酸酯类农药残留的测定。     

机采籽棉预处理清理单元的结构设计及参数优化

统收式采棉机作业质量受限于机采籽棉预处理装置清理效率。本研究着力开展对机采籽棉预处理清理作业单元的结构参数及运行参数组合优化。考察4个因子锯齿间距A、锯齿辊直径B、锯齿辊转速C、排杂棒间距D的影响，2个试验指标为损失率X、含杂率Y。采棉机作业时采用三级串联的清理单元，后一级都能够对前一级清理单元的籽棉损失再次回收。因此，以单独一级清理作业单元为研究对象时，以籽棉含杂率为主，籽棉的损失率为辅的目标参数，选择含杂率权重分配为70%，损失率权重分配为30%。试验设计为2、4混合水平正交重复试验。试验结果表明：最优组合为A＝38 mm，B＝340 mm，C＝280 r·min^－1，D＝20 mm，综合评分为96.5。     

蔬菜水果中赤霉素残留量HPLC检测方法的研究

对蔬菜水果样品中的赤霉素残留量采用高效液相色谱方法进行测定。结果表明：样品中赤霉素经80%甲醇溶液提取，用石油醚脱色，经过乙酸乙酯液液萃取和磷酸缓冲液反萃取，再用乙酸乙酯萃取净化，然后采用C18色谱柱分离，以甲醇和0.1%的冰乙酸水溶液为流动相洗脱，用高效液相色谱紫外检测器206 nm波长检测，以保留时间定性，外标法定量。在此优化实验条件下，赤霉素标准溶液在0.25～50 mg/L呈良好线性，r＝0.999 9，检出限为0.067 mg/kg。6种蔬菜水果的添加回收率为71.6%～105.2%，RSD为2.1%～9.8%。     

柱花草炭疽病流行因子初探

通过连续两年对6个不同柱花草品种炭疽病的田间发病流行情况进行定位观察，并将炭疽病病情与大气温度、湿度和雨量之间进行相关分析。结果表明：柱花草炭疽病病情严重度与空气相对湿度成显著的正相关(r＝0.440 37，Pr＝0.045 7)，与温度成负相关(r＝-0.492 63，Pr＝0.023 3)，而与雨量相关性不明显。一年中病害的发生和流行有两个高峰，主峰出现在8～9月份，次峰出现在1月份左右。发病高峰一般出现在降水量高峰之后，二者间存在约一个月的时间差。     

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.     

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.     

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.     

Redox Status and Neuro Inflammation Indexes in Cerebellum and Motor Cortex of Wistar Rats Supplemented with Natural Sources of Omega-3 Fatty Acids and Astaxanthin: Fish Oil,Krill Oil,and Algal Biomass

Health authorities worldwide have consistently recommended the regular consumption of marine fishes and seafood to preserve memory, sustain cognitive functions, and prevent neurodegenerative processes in humans. Shrimp, crabs, lobster, and salmon are of particular interest in the human diet due to their substantial provision of omega-3 fatty acids (n-3/PUFAs) and the antioxidant carotenoid astaxanthin (ASTA). However, the optimal ratio between these nutraceuticals in natural sources is apparently the key factor for maximum protection against most neuro-motor disorders. Therefore, we aimed here to investigate the effects of a long-term supplementation with (n-3)/PUFAs-rich fish oil, ASTA-rich algal biomass, the combination of them, or krill oil (a natural combination of both nutrients) on baseline redox balance and neuro-inflammation indexes in cerebellum and motor cortex of Wistar rats. Significant changes in redox metabolism were only observed upon ASTA supplementation, which reinforce its antioxidant properties with a putative mitochondrial-centered action in rat brain. Krill oil imposed mild astrocyte activation in motor cortex of Wistar rats, although no redox or inflammatory index was concomitantly altered. In summary, there is no experimental evidence that krill oil, fish oil, oralgal biomass (minor variation), drastically change the baseline oxidative conditions or the neuro-inflammatory scenario in neuromotor-associated rat brain regions.     

Potential of dry fractionation of wheat bran for the development of food ingredients,part II: Electrostatic separation of particles

Wheat bran is a composite material made of several layers, such as pericarp, testa and aleurone. It could be fractionated into purified fractions, which might either be used as food ingredients, or serve as a starting material for extraction of bioactive compounds. The aim of this work was to evaluate the potential of using electrostatic separation as a way to obtain purified fractions from wheat bran. Ultrafine-ground bran obtained either by cryogenic grinding or by grinding at ambient temperature was used as starting material. The ultrafine bran was then charged by tribo-electrification and introduced in a chamber containing two high voltage electrodes, where bran particles were separated depending on their acquired charge, allowing positively and negatively charged fractions to be collected separately. The particle size distribution, microstructure and biochemical composition of the obtained fractions were studied. The charge of the particles was influenced by their biochemical composition: particles rich in highly branched and cross-linked arabinoxylans (pericarp) were separated from particles rich in β-glucan, ferulic acid and para-coumaric acid (aleurone cell walls). The testa and the intracellular compounds from aleurone were not highly charged, neither positively nor negatively. The most positively charged fraction represented 34% of the initial bran, and contained 62% of the ferulic acid present in the initial bran. The yield of the separation process was good (5.4% loss), and could be further increased.     

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.     

<Emphasis Type="Italic">Pulque</Emphasis>, An Alcoholic Drink from Rural Mexico,Contains Phytase. Its <Emphasis Type="Italic">in vitro</Emphasis> Effects on Corn Tortilla

Pulque is made by fermenting the agave sap or aguamiel of Agave atrovirens with a whole array of microorganisms present in the environment including several lactic acid bacteria and yeasts such as Saccharomyces cerevisiae. Ascorbic acid was determined in pulque and aguamiel, respectively. Phytase activity in lees, liquid and freeze-dried pulque was assayed by measuring the appearance of phosphate from phytate by a colorimetric method likewise phosphate from phytate present in fresh corn tortilla was measured after in vitro incubation with pulque. Iron, zinc, calcium, magnesium and selenium contents were measured in pulque and corn tortilla as well as in nixtamalized corn flour (NCF), the latter is used to make instant tortilla, since corn provides most of the energy as well as most of the phytate in the Mexican rural diet. Pulque showed phytase activity but much less ascorbic acid and iron than previously reported; additionally, phytase in pulque hydrolyzed most of phytate’s corn tortilla. Lees, which is mostly made of pulque’s microbiota, significantly accumulated iron and zinc but no selenium. NCF was fortified with iron by the manufacturers but poorly blended. There were significant differences on selenium content between tortillas samples, apparently some soils in central Mexico are selenium deficient. Moderate pulque intake appears to increase the bioavailability of iron and zinc bound by phytate in corn.     

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.