Comparison of Antioxidant Components and Activity of Buckwheat and Wheat Flours

Plant phenolics and tocopherols content were determined in light and wholegrain buckwheat and wheat flour. Antioxidant activity of flours were comparatively assessed by scavenging activity on 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH^•), hydroxyl (^•OH), and superoxide anion (O₂^•–) radicals, reducing activity, and chelating activity on Fe²⁺. Rutin, quercetin, and ferulic acid were quantified in both buckwheat flours, while ferulic acid was quantified in wholegrain wheat flour. Significantly higher content of phenolics and tocopherols was found in buckwheat than in wheat flours. Tocopherols in buckwheat flours were present in the order: γ‐ > α‐>> δ‐tocopherol, and in wheat flours: α‐ > γ‐ >> δ‐tocopherol. Buckwheat flours possessed better scavenging abilities on DPPH^•, ^•OH and O₂^•– radicals, as well as better reducing activity, while wheat flours showed better chelating activity on Fe²⁺, according to IC₅₀ values. Results suggest the possibility of improving the antioxidant properties of wheat‐based food products through addition of buckwheat flour.     

森林土壤不同粒径颗粒的碳矿化研究

土壤是由不同粒径颗粒组成的,各粒径颗粒的性质差异大、在土壤中的空间位置不同。为了研究它们各自碳的变化差异,评估这些颗粒在土壤有机碳稳定和周转中的作用。选择亚热带阔叶林土壤,采用物理分组的方法,获得不同粒径土壤颗粒（>2 000、2 000~250、250~53、<53、53~20、20~2、<2μm）,与全土等重量开展矿化试验,研究碳矿化量差异、主要碳形态变化及其相互关系,反向探究不同粒径颗粒在全土壤中的作用。结果表明,不同粒径颗粒按照质量比例作为权重计算的CO2累积排放量、全碳、C/N、芳香性指数、游离氧化铁含量占全土的95.0%~101.8%。<2 μm和20~2 μm土壤颗粒CO2累积排放量显著高于其他颗粒和全土。全土及各颗粒土壤CO2累积排放量与比表面积、总孔隙体积、全碳、土壤可溶性有机碳（DOC, Dissolved organic carbon）、 土壤微生物生物量碳 (Soil microbial biomass carbon, MBC)、易氧化碳、游离氧化铁呈正相关性,而与C/N呈负相关性。通过对不同粒径颗粒16个指标降维分析,综合特征指数显示<2 μm和20~2 μm颗粒最高,即它们的综合作用最大。因此,全土壤的碳变化可追溯到土壤不同粒径颗粒碳的不同变化及关系,且土壤小粒径的团聚或被大粒径颗粒包闭可能是降低全土碳矿化的机理之一,有利于维持全土壤碳的稳定或增加保存。     

不同粒径土壤的光谱特征差异分析

通过野外采集土样,研磨后获取不同粒径(2、1、0.5、0.25、0.15和0.05 mm)土壤,在暗室内进行光谱测定。分别采用光谱数据微分变换和连续统去除的方法,研究不同粒径土壤的光谱特征差异,探索不同粒径处理对土壤光谱特征的影响。结果表明:不同粒径土壤的平均光谱反射率在全波段、可见光、红外波段都随土壤粒径的减小而增加;土壤光谱反射率与土壤粒径呈负相关关系。微分变换放大了某些在原始光谱数据中比较隐晦的信息。可见光、全波段平均反射率均在土壤粒径0.25 nm时,呈现出更明显的增长趋势,而红外波段则在土壤粒径0.15 mm时,增长趋势更为明显;土壤光谱在450和490 nm处的吸收峰值随土壤粒径的减小呈多项式分布;土壤全波段光谱反射率随着粒径的减小呈幂函数增长。     

磺胺嘧啶在黑土及其不同粒径组分中的吸附行为研究

采用批平衡吸附试验法,研究了磺胺嘧啶在黑土及其不同粒径中的吸附行为。结果表明,磺胺嘧啶的吸附不同程度地偏离线性模型,但均可用Freundlich模型和Langmuir模型进行良好地线性拟合。黑土（〈0.2mm）及其不同粒径（粘粒：〈0.002mm、粉粒：0.002~0.02mm、砂粒：0.02~0.2mm）的Freundlich容量因子Kf值分别为29.6、53.1、32.9L.kg-1和21.6L.kg-1,说明磺胺嘧啶在黑土及其不同粒径中的吸附行为存在差异。将吸附参数Kf进行碳标化处理后,Koc值除粉粒外,其他基本一致。随着溶液pH的持续增加（1.0~10.0）,黑土及其不同粒径中的磺胺嘧啶的吸附参数lgKf呈现先急剧降低然后稍微回升的趋势,由此推测,阳离子交换作用可能是磺胺嘧啶土壤吸附的重要机制。过氧化氢处理去除土壤有机质后,黑土的Kd值从1.92L.kg-1降为1.22L.kg-1,磺胺嘧啶的吸附量由16.5mg.kg-1降低到11.2mg.kg-1,说明有机质含量也是影响磺胺嘧啶吸附行为的重要因素。     

In Vitro Bile Acid Binding Capacity of Wheat Bran with Different Particle Sizes

The bile acid binding capacity of wheat bran with different particle sizes was determined. Unmilled wheat bran with an average particle size of 900 μm (WB‐900), milled wheat bran at two particle sizes, 500 and 200 μm (WB‐500 and WB‐200), and all three bran samples washed with water (WWB‐900, WWB‐500, and WWB‐200) were mixed with bile acids at pH 6.3 to determine their in vitro adsorption capacity. On a dry matter basis, the order of relative bile acid binding values was WB‐900 ∼ WB‐500 > WWB‐900 > WB‐200 > WWB‐500 > WWB‐200. Data suggests that the surface area as measured by the Brunauer–Emmett–Teller (BET) method and water holding capacity may significantly affect the bile acid binding capacity of wheat bran. As the BET surface area increased with decreasing particle size, the water holding capacity and bile acid binding decreased. Bile acid binding capacity of wheat bran appears to be linked to the ability of the samples to physically adsorb the bile acids. Bile acid binding capacity significantly decreased with reduction in particle size of wheat bran after water washing.     

Bioavailability of Calcium in Breads Fortified with Different Calcium Sources

This study used young rats as the test model to examine the relative bioavailability (RB) of calcium (Ca) in breads fortified with five different Ca sources. These sources included two inorganic (Ca carbonate and Ca sulfate) and two organic (Ca citrate and Ca lactate) Ca sources, and a brandname Ca supplement. RB was assessed based on rats' femur Ca content and Ca absorption data. No differences of any physiological significance were observed in RB of Ca among the five sources tested. Compared to Ca carbonate (bioavailability arbitrarily set at 100%), RB of Ca in Ca sulfate was 105%, in Ca citrate 103%, in Ca lactate 102%, and in the Ca supplement 102%. This suggests that foods fortified with Ca carbonate or Ca sulfate, which are commonly used for this purpose, may be as good a source of utilizable Ca as more expensive Ca sources such as prescribed or nonprescribed Ca supplements.     

不同采收时期蜂王浆抗氧化活性研究

为研究不同采收时间对蜂王浆品质的影响,以4-9月份采收的蜂王浆为研究对象,通过比较不同采收时间蜂王浆中蜂王浆主蛋白(MRJPs)、总水溶性蛋白和多酚的含量,分析了MRJPs与自由基清除能力和总抗氧化能力的相关性。结果表明,不同采收期蜂王浆中MRJPs含量存在显著差异(P<0.05),且6月份采收的MRJPs含量最低。水溶性蛋白及总酚含量差异不大(P>0.05)。蜂王浆自由基清除能力与MRJP1和 MRJP3含量的相关系数达0.828和0.847;总抗氧化能力与MRJP1和 MRJP3含量的相关系数分别为0.680和0.743。蜂王浆的抗氧化活性与其MRJPs存在一定程度的正相关,但与多酚含量相关性不明显,说明其自由基清除能力与总抗氧化活性可能是多种抗氧化性活性物质共同作用的结果。本研究为蜂王浆的抗氧化活性研究提供了参考。     

粒径对生物滞留池流场及生物膜形态的影响

[目的] 分析填料粒径对生物滞留池（BRC）渗透性能及微生物膜形态的作用机理,以期优选出适合生物滞留池填料层的颗粒粒径及相应填充的孔隙率。[方法] 采用数值模拟和试验实测相结合的方法,利用Fluent软件对BRC小尺度计算区域范围内的流场形态进行模拟,对6种粒径（0.5,1.0,2.0,4.0,6.0,8.0 mm）下的流线图、压力分布及变化图进行综合对比分析。为验证模拟结果的正确性,对不同颗粒粒径进行生物膜培养和运行,测定颗粒表面生物膜厚度。[结果] 平均粒径为0.5~1.0 mm时流场形态最好,可形成结构合理数量较多的小涡流,有利于水流渗透及物质传递的进行,实测生物膜也表明粒径为1.0 mm时,微生物膜生长最为均匀且生物量最大。[结论] 填料的粒径会影响BRC的运行效果,数值模拟可为实际粒径的选取提供参考。     

Reactivity of Sedimentary and Metamorphic Limestones of Different Particle Sizes under Controlled Conditions

The efficiency of limestone in amending soil acidity is primarily based on the particle size and the neutralization value of the ground rock, but the origin of the rock can also affect its reactivity. The aim of this work was to evaluate, under controlled conditions, the efficiency of the reactivity of sedimentary limestones of different particle sizes in neutralizing soil acidity. The experiment was conducted using a clayey and a sandy soil, and the treatments consisted of four samples of a sedimentary limestone (with the same neutralization values but different particle sizes), two metamorphic limestones and an untreated control. In the first months of incubation, the sedimentary limestones demonstrated higher soil amelioration abilities than the metamorphic limestones, but all samples used in the study achieved the goal of neutralizing soil acidity to desired values: a base saturation (BS) of ~70% and a pH > 6.0. In sedimentary limestones, the availability of calcium (Ca) and magnesium (Mg) was more closely related to the levels of Ca oxide (CaO) in the amendment than to the size of the particles. The results of this study suggest that the currently used equation may underestimate the reactivity of certain limestones.     

保水剂粒径对秦巴山区土壤水分及烤烟生长的影响

[目的]探究保水剂粒径对秦巴山区土壤水分及烤烟生长的影响,为改善秦巴山区烟田的土壤环境以及促进保水剂在烤烟生产中的应用提供科学支持。[方法]以不施用保水剂为对照,以粉末状(粒径0.18mm)、细颗粒状(粒径0.18～2.25mm)和颗粒状(粒径2.25～3.25mm)的聚丙烯酸钾保水剂为研究材料,监测不同粒径的保水剂对秦巴山区黄棕壤烟田土壤水分、土壤容重及烤烟生长、烤烟品质及经济性状的影响。[结果]不同粒径的聚丙烯酸钾保水剂在烤烟不同生长期均可提高0—40cm土层土壤水分,降低0—40cm土层土壤容重,但对40cm以下土层的土壤水分无显著影响,其中细颗粒状保水剂对土壤水分、土壤容重影响较大。不同粒径的保水剂均可促进烤烟根系生长及茎叶生长,提高烟叶产量与产值,降低下等烟的比例,其中细颗粒状保水剂对烤烟最大叶片、根系生长量、产量及产值影响较大,但粉末状保水剂对上等烟比例影响较大。[结论]不同粒径的保水剂均可提高烤烟品质,其中细颗粒状保水剂对烟碱、总氮、钾及氯的影响较大,粉末状保水剂对总糖和还原糖影响较大。秦巴山区黄棕壤烟田应选用细颗粒状的聚丙烯酸钾保水剂。     

连续失水-复水中不同粒径保水剂对土壤结构和水分特性的影响

为明确土壤干湿交替环境下保水剂与土壤颗粒之间的作用方式及保水剂对土壤结构和水分有效性的影响.通过土柱模拟试验,研究连续失水—复水条件下,不同粒径(>0.85,0.6～0.85,0.30～0.45 mm)保水剂对土壤水分特性、土壤团聚体分布和结构稳定性的作用,以及保水剂—土壤混合体价键结构的微观变化特征.结果表明:第1次...     

胶体颗粒对不同粒径饱和多孔介质渗透性的影响

探讨胶体颗粒在多孔介质中迁移所发生的物理、化学及生物作用过程,在许多学科中具有重要的科学意义。采用室内石英砂柱实验,开展了定水头条件下不同浓度和粒径的胶体颗粒在饱和多孔介质中的运移行为研究。共使用了3种胶体粒径、3种浓度的胶体溶液和3种粒径范围的石英砂。实验表明:多孔介质的相对渗透系数K/K0(K为各时刻计算所得的渗透系数,K0为初始渗透系数)减小程度与颗粒浓度成正比;胶体颗粒越大,越易在表层沉积,而小颗粒易向下部迁移,但总体来看粒径效应没有浓度效应明显;当胶体颗粒在不同粒径的饱和多孔介质中迁移时,粒径大的多孔介质各段K/K0均有明显降低,而粒径小的只在表层变化明显。不同条件下总体相对渗透系数与时间之间呈二次方相关关系,但当多孔介质粒径较小时,相关性不显著。介质渗流流速及砂柱不同位置胶体颗粒浓度变化与介质渗透性变化相对应。用扫描电镜(Scanning Electron Microscope,SEM)进行定性表征,进一步说明胶体颗粒会堵塞多孔介质孔隙影响其渗透性。实验中发现当输入浓度C0小于0.5 g·L–1且dp/Dp>0.018(dp为胶体颗粒粒径,Dp为石英砂算数平均粒径)时,会出现多孔介质局部K/K0增大的现象。     

镧、铈对铜胁迫下豌豆幼苗抗氧化酶系统的影响

本试验以豌豆为研究对象,研究了豌豆幼苗在受到高浓度Cu离子(100mg·L-1)胁迫下,经2种稀土(La、Ce)元素分别处理后对豌豆幼苗的细胞抗氧化酶活性及脂质过氧化产物MDA含量的影响.结果表明,Cu离子胁迫降低了豌豆幼苗SOD、POD和CAT活性,增加了膜脂过氧化产物MDA含量.适宜浓度的La(5 ～ 10mg·L-1)和Ce(5～ 20mg·L-1)可分别有效提高豌豆幼苗的3种抗氧化酶活性并降低MDA含量,显著减轻了Cu胁迫对豌豆幼苗造成的毒害效应(P＜0.05).这说明La、Ce处理能有效提高细胞清除活性氧的能力,一定程度上缓解了Cu离子胁迫对豌豆幼苗膜系统带来的伤害.进一步研究还表明,La处理后对提高豌豆幼苗抗氧化酶活性和降低MDA含量的能力要显著优于Ce.但高浓度(≥40mg·L-1)的两种稀土反而会加剧Cu对豌豆幼苗抗氧化酶系统的伤害,表现出与Cu离子协同胁迫的毒害效应.     

稻田垄作免耕对土壤真菌多样性分布的影响

在水田长期垄作免耕处理下,研究了土壤真菌多样性及其在不同大小团聚体中的分布.结果表明,垄作免耕处理下,耕层土壤中,真菌主要分布于粒级为1.0～0.25 mm的土壤团聚体中,同时在＞0.053 mm的各级土壤团聚体中垄作免耕处理下真菌数量多于常规轮作处理;垄作免耕处理的各级土壤团聚体中都有毛霉和根霉存在,且1.0～0.25mm土壤团聚体中属类最丰富,其simpson多样性指数为0.93,Shannon多样性指数为1.24,常规轮作下属类丰度没有明显变化.稻田垄作免耕提高了不同团聚体中真菌的数量、多样性,改变了真菌在不同大小团聚体中的分布状况.     

猪和奶牛粪便的粒径及养分分布对固液分离效率的影响

以猪、奶牛粪便为材料,按＜0.15、0.15-0.5、0.5-1.0、＞1.0 mm不同粒径,分析了猪、奶牛粪便粒径分布,同时分析了4种不同粒径颗粒中N、P、K养分含量,采用XY型螺旋式畜禽粪便固液分离机,在0.5、1.0 mm两种孔径筛网下,进行了固液分离,分析比较了机械固液分离对相应粒径粪便固形物及养分回收效率。结果表明,猪、奶牛粪便粒径分布以〈0.15 mm小颗粒为主,占其粪便重量的57.99%-68.34%,奶牛粪便颗粒粒径大于猪粪便,仔猪与育成牛粪便粒径小于育肥猪与泌乳牛粪便。猪、奶牛粪便中N、P、K养分近80％以上呈水溶性或存在于〈0.15 mm小颗粒之中。粪便机械固液分离获得的固形物与固形物中N、P养分回收比例高于相应筛网孔径粪便颗粒与养分所占比例,奶牛粪便固形物回收率为45.5％,远高于猪粪的27.8％,N、P养分回收率分别为7.14%-19.71%、7.38%-21.18％。     

不同石榴品种果实酚类物质及抗氧化活性研究

为探明石榴不同栽培地区和不同品种间酚类物质含量分布特征,筛选抗氧化能力强的功能型优良品种,以山东、云南、新疆和四川地区8个主栽石榴品种的成熟期果实为试材,利用常规品质分析方法和高效液相色谱技术,对其果实品质、酚类物质和抗氧化能力进行分析。结果表明,石榴品种间果实各品质指标存在显著差异,其中,喀什甜单果质量、可溶性糖和维生素C含量最高,甜绿籽固酸比最高,泰山红可溶性固形物含量最高,红玛瑙可滴定酸含量最高。不同石榴品种果皮中酚类物质含量与抗氧化能力均最高;果汁次之,种子最低。喀什甜果皮和红玛瑙种子中酚类物质含量和DPPH自由基清除率均最高;果汁中花青苷含量和DPPH自由基清除率分别在千籽红和大青皮甜中最高,安石榴苷、没食子酸、鞣花酸、总黄酮和总酚含量在红玛瑙中最高;果皮中安石榴苷含量(平均为135.00 mg·g-1)占总酚的48.94%,是石榴果实中最主要的酚类物质。果实品质指标间、果实品质与酚类物质间存在一定的相关性,安石榴苷、没食子酸、鞣花酸、花青苷、总黄酮和总酚间互为正相关,各指标与DPPH自由基清除率均正相关。红玛瑙、喀什红和千籽红果实的综合品质佳,富含酚类物质,是值得推广和开发利用的优良品种。研究结果为石榴加工产品的研发和新品种选育提供了理论依据。     

Effect of Gamma Irradiation on the Functional and Nutritive Properties of Rice Flours from Different Cultivars

The purpose of this work was to study the effect of minimal doses of γ‐irradiation to reduce microbial loads (Co⁶⁰, doses of 0, 1.5, and 3 kGy) on flour from three rice cultivars with different amylose contents (AC) grown in Argentina: RP2 (AC 25%), Yeruá (Y) (AC 19%), and Higokumochi (H) (AC 5%). Studies on some starch characteristics such as digestibility (rate of starch hydrolysis in vitro), gel viscosity and syneresis, and scanning electron microscopy (SEM) were performed. Results showed that γ‐irradiation affects rice functional and nutritive characteristics proportionally with the dosage used. With 3 kGy, original digestibility values increased 37.5, 60, and 76%; gel viscosity decreased 52, 77, and 90%; and syneresis increased 0, 193, and 546% on RP2, Y, and H, respectively. Amylopectin was the starch fraction most affected as shown by SEM. Although some of these changes in cultivar attributes might be considered negative for traditional food formulations, they could help in the design of new foods or for fermented beverages.     

Influence of Cadmium Toxicity on Growth and Antioxidant Enzyme Activity in Rice Cultivars with Different Grain Cadmium Accumulation

Abstract

The effect of cadmium (Cd) toxicity on growth, lipid peroxidation, and antioxidant enzymes was studied using two rice cultivars, Bing 97252 with low and Xiushui 63 with high grain Cd accumulation. Plants were exposed to 0–5 μ M Cd in hydroponic culture. Cadmium stress inhibited plant height and chlorophyll content and altered melondialdehyde (MDA) content and the activities of superoxide dismutase (SOD), catalase (CAT), and peroxidase (POD). Roots and shoots responded differently to Cd in terms of antioxidant enzyme activity. Generally, the activities of SOD, POD, and CAT decreased with increase in Cd level, while the activity of MDA increased with increase in Cd level. With the increase in Cd concentration in nutrient solution, MDA content in shoots and roots of Xiushui 63 increased at a much higher rate than did that of Bing 97252 at both growth stages. At booting stage, a decrease of 46%–52% in SOD activity was noted in plant roots grown under 5 μ M Cd, while at tillering stage the decrease was 13%–19% compared with the control. A significant decrease in chlorophyll content and plant height was noted under higher Cd treatment (1.0 and 5.0 μ mol) at two stages. The higher MDA and lower chlorophyll content in the cultivar Xiushui 63 showed that it is more sensitive to Cd than the cultivar Bing 97252.     

祁连山区不同尺寸双环入渗仪对比试验

设计7组不同内外径的双环入渗仪,在位于祁连山区的黑河上游平坦草地开展多次野外土壤入渗试验,对比分析双环入渗仪内外环尺寸对土壤入渗率和饱和导水率的影响。结果表明,双环入渗仪内径相同时,外径越大则稳定入渗率和饱和导水率越小;外径相同时,内径越小则稳定入渗率和饱和导水率越小。初始入渗率与双环入渗仪尺寸关系不显著,但稳定入渗率和饱和导水率与入渗仪缓冲指数呈显著负相关。综合考虑安装简便,用水条件,试验可靠等多方面因素,推荐山区使用内径20cm,外径40cm的双环入渗仪。     

土壤不同粒径有机无机复合体对丁草胺的吸附特性

为了解土壤不同粒径组分对农药吸附-解吸行为的影响和吸附贡献率,以及不同粒径组分中有机无机组分的结合方式和复合程度如何影响有机质对农药的吸附,选取我国6个省区的7种理化性质差别较大的土壤,并采用物理方法提取该7种土壤的三个粒径有机无机复合体(黏粒:0.002mm;粉粒:0.02~0.002 mm;砂粒:0.05~0.02 mm)为研究材料,采用批量平衡法研究丁草胺在不同土壤和不同粒径有机无机复合体固/液界面的分配规律。同时,定量计算土壤各粒径组分对丁草胺的吸附贡献率,并从有机无机复合体角度探讨不同粒径组分中总有机碳(TOC)对丁草胺的吸附特性。结果表明:土壤黏粒组分对丁草胺具有最大的吸附量和较小的解吸率,而砂粒组分对丁草胺则具有较小的吸附量和最大的解吸率。土壤黏粒、粉粒和砂粒组分对丁草胺的吸附贡献率分别为36.7%~72.4%、21.7%~50.5%和10%。TOC是影响各粒径组分对丁草胺吸附的主要原因,但其影响程度受各粒径组分中TOC的理化性质以及其与无机矿物的复合程度控制。