米糠、锯末与蛋鸡粪堆肥过程中氮素的变化特征

探讨米糠、锯末与蛋鸡粪堆肥过程中氮素的变化特征,旨在为制定蛋鸡粪堆肥规模化生产中减少氮素损失、减少氨气挥发的调控措施提供科学依据。试验设4个处理,蛋鸡粪-米糠、蛋鸡粪-锯末,隔天翻堆1次;蛋鸡粪-米糠-锯末、蛋鸡粪-锯末,每天翻堆1次,定期测定物料理化指标。研究表明,堆肥过程中,铵态氮向硝态氮转化受抑制,氮素转化以有机氮与铵态氮间的相互转化以及铵态氮以氨气形式挥发为主,铵态氮主要以氨气形式挥发造成全氮损失。氮素转化与损失与堆肥温度、pH、O2等环境参数有关,高温、高pH促进氨气挥发;充足的氧气可促进铵态氮向微生物量态氮(有机氮)转化。这些参数主要受堆体结构对堆肥氧气供应和有机质分解的影响。因此,可以尝试在米糠和锯末中添加来源广泛的秸秆类辅料,通过改善堆体结构(容重)来减少氮素损失。     

燕麦秸—稻草混合青贮的研究

为解决南方冬—春季牧草缺乏及能够合理利用南方稻草资源,对燕麦秸—稻草混合青贮样品设置了4个处理.结果表明,1号处理pH、氨态氮占总氮含量显著高于其他3组青贮饲料（P＜0.05）,4号处理的pH和氨态氮占总氮含量显著低于其他3组青贮饲料（P＜0.05）,4号处理粗蛋白含量最高,且4个处理间粗蛋白含量存显著性差异（P＜0.05）;4个处理组均未检测出丁酸.综合试验结果,单贮燕麦秸可以得到优良的青贮饲料,且鲜燕麦添加比例为70％的燕麦—稻草混贮效果与其相近.     

鸭疱疹病毒1型的gB蛋白截短表达及其ELISA检测

参照已发表的鸭肠炎病毒（Duck enteritis virus,DEV）基因组序列,利用生物学软件DNAstar进行序列分析,设计并合成一对特异性引物,PCR扩增了长855 bp的gB基因片段.将目的片段克隆至pMD18-T载体,经PCR、酶切及测序鉴定后,定向克隆至pET30a表达载体中,经PCR、酶切鉴定正确后,重组质粒转化BL21表达茵,经IPTG诱导后获得了以包涵体形式表达的重组蛋白.重组蛋白在变性的条件下采用Ni柱亲和层析法纯化,变性蛋白复性后,Western blot检测表明重组蛋白具有良好的反应活性,以该蛋白作为诊断抗原,初步建立了检测鸭肠炎病毒抗体的间接ELISA诊断方法,为鸭肠炎病毒抗体诊断试剂盒的研制奠定了基础.     

Bubbles in chapatti doughs

Traditionally, chapattis are flatbreads made from atta (wholemeal Indian wheat flour). Non-atta chapattis have not been popular due to substandard product quality. To investigate what makes atta special for making chapattis, products were made using atta, Australian wholemeal wheat flour, gluten-free lupin flour, and a blend of lupin and wheat flours. Doughs were characterised by measuring strain-hardening and elastic recovery in compression and also bubble structures via 3-D X-ray micro-tomography. A method was developed to identify and separate bran, which appears as bubbles, in scans of doughs.     

Interactive Effects of CO2 and O3 on the Growth of Trisetum flavescens and Trifolium pratense Grown in Monoculture or a Bi-Species Mixture

SUMMARY

Golden oat grass (Trisetum flavescens L.) and red clover (Trifolium pratense L.) were grown as monocultures or bi-species mixtures under controlled conditions and exposed to ambient (350 ppm) or elevated (580 ppm) CO₂, with or without addition of O₃ (diel profile with 150 ppb maximum). Shoot biomass measurements after the initial growth and two re-growth periods were used to determine the specific responses of both species, and the difference in the specific response between monocultures and mixtures. T. pratense was much more responsive to CO₂, O₃, and their combination, compared to T. flavescens. In the case of O₃ but not of CO₂, the difference in sensitivity between species was larger in mixture than in monoculture. In contrast to elevated CO₂, O₃ significantly reduced the root:shoot ratio in the mixture, which could explain the increasing negative effect of O₃ on clover with progressing harvests.

The relative CO₂ stimulation of T. pratense and of the cumulative mixture shoot biomass was larger in the presence than in the absence of O₃, which was due to an almost complete protection from O₃ stress by elevated CO₂. In the mixture, the fraction of T. flavescens was small and increased during the experiment; this increase was most pronounced with O3, but any change in mixture biomass was dominated by the response of T. repens.

The results confirm that in grass/legume mixtures legumes are most sensitive to elevated CO₂ and O₃, but the magnitude of specific responses depends on canopy structure and of plant development. Elevated CO₂ minimizes the negative impacts of O₃ stress on above- and below-ground plant growth.     

利用米糠外添GAD制备γ-氨基丁酸的工艺条件优化

以稻米加工副产品米糠为原料,采用单因素和正交实验确定了外添谷氨酸脱羧酶(GAD)制备γ-氨基丁酸(GABA)的最佳工艺条件:GAD酶用量175u/g,酶解时间2h,pH5.5,酶解温度45℃。经验证实验,在最佳工艺条件下GABA生成量为1530.7mg/100g米糠。     

进口小麦麸皮霉菌总数不确定度的评定

以测定进口哈萨克斯坦小麦麸皮中霉菌总数为例,建立了数学模型,计算出霉菌总数测量扩展不确定度为0．2810。由于霉菌总数各批之间测量结果散发极大,因此,哈萨克斯坦进口小麦麸皮霉菌总数测量结果的不确定度提供95％的置信概率,取值区间为2．3×10^2≤x≤8．4×10^2。     

米糠稳定化对米糠中游离脂肪酸值的影响

[目的]研究米糠稳定化对米糠中游离脂肪酸值的影响.[方法]对米糠进行干热、湿热、微波和挤压等稳定化处理,并通过测定游离脂肪酸值确定米糠稳定化的最有效方法.[结果]在相同储藏期内稳定化效果顺序为：微波湿热处理＞挤压处理＞湿热处理＞干热处理.从短时间来看,通过挤压法对米糠的稳定效果最好,在130℃下用单螺杆挤压机处理含水量25％的米糠,3d后游离脂肪酸值才达到3.28％;从米糠长期保存考虑,微波湿热处理（25％含水量,60s）效果优于挤压处理（130℃、含水量25％）.[结论]干热法、湿热法、微波法和挤压法等4种稳定方法对抑制米糠游离脂肪酸值的增加都有一定效果.     

Regrowth Rates of Timothy and Meadow Fescue as Related to the Content of Remaining Water-soluble Carbohydrates and Non-elongated Tillers

The relationship between regrowth rates and the content of water-soluble carbohydrates in stubble (WSC) and percentage of non-elongated tillers (PNT) was studied in timothy (Phleum pratense L.) and meadow fescue (Festuca pratensis Huds.) cut at different phenological stages. Single plants were grown in pots and cut outdoors and then regrown under controlled climatic conditions. The data for the dry matter production during the following 3 weeks were fitted to an expolinear growth equation to determine an initial maximum relative regrowth rate (R _m) and a daily maximum regrowth rate (C _m). C _m appeared to be positively correlated to PNT in both species, whereas R _m was increased with increasing WSC. For regrowth after later cuts of meadow fescue there was a positive contribution to R _m by PNT.     

玉米皮多酚提取工艺优化及抗氧化性研究

为探究超声辅助酶解法提取玉米皮多酚的最优工艺,并探讨其体外抗氧化活性,以玉米皮多酚提取量为响应值,分别考察超声时间、提取温度、料液比和酶添加量4个因素对提取效果的影响。在单因素试验的基础上,采用中心组合响应面分析法对提取工艺进行优化。结果表明,最佳提取条件为:超声时间6.5 min、酶解温度55℃、液料比41 mL·g^-1、木聚糖酶添加量2.10%,此条件下,玉米皮多酚提取量最高,为7.26 ± 0.15 mg·g^-1,与响应面预测值7.17 mg·g^-1相近。DPPH·和ABTS⁺·清除法抗氧化试验结果表明,玉米皮多酚具有较强的抗氧化能力,可作为潜在天然抗氧化剂应用于食品行业。本研究结果为玉米加工副产物玉米皮综合应用提供了理论依据。