响应面法优化大豆油下脚料制备生物柴油工艺的研究

随着全球性能源的日益短缺与环境的逐渐恶化,生物柴油作为一种无毒、可生物降解和再生的替代燃料正受到越来越多的关注.研究了利用大豆油下脚料(油脚、皂脚混合物)制取生物柴油的工艺过程.先用乙醚室温下萃取下脚料,料液比1∶2(g∶mL),萃取时间2 h.离心后分为3层,上层有机相再经丙酮萃取分离出磷脂和中性油,磷脂作为高附加值副产品回收再利用以降低生物柴油的生产成本.分离出的皂相经酸化转化为混合脂肪酸,混合脂肪酸用于酸催化的酯化反应.利用响应面法对酯化反应工艺参数进行了优化,并得到回归方程.方差分析结果表明:在各影响因素中,醇酸摩尔比对转化率的影响最大,其次是反应温度和反应时间,醇酸摩尔比和反应温度的交互作用显著.酯化反应优化后的工艺条件为醇酸摩尔比为5∶1,催化剂(H2SO4)添加量3%(wt.%),反应温度为87℃,反应时间4.74 h,在此条件下转化率达到92.5%.     

有机硅氧烷接枝改性天然胶乳的制备及结构表征

采用接枝共聚制备有机硅氧烷接枝改性天然胶乳,着重考察偶联剂种类和用量、引发剂用量、胶乳浓度、反应温度、反应时间和有机硅氧烷种类及用量等对有机硅在接枝共聚反应中的转化率和接枝率的影响,并采用正交设计试验,探索有机硅氧烷改性天然胶乳的适宜工艺条件。结果表明∶VD4接枝改性天然胶乳的转化率和接枝率均比D2的要高;与其他偶联剂相比,A-171的接枝率也较高;随着有机硅单体用量的增加、反应时间延长、反应温度升高,有机硅单体的转化率和接枝率都升高。有机硅氧烷改性天然胶乳的适宜工艺条件∶胶乳浓度为50%,反应温度为55℃,反应时间为4h,偶联剂A-171用量为1.2%（占橡胶的质量百分率,下同）,有机硅用量为15%,引发剂用量为1.0%。IR分析结果表明∶有机硅氧烷与天然橡胶分子链存在接枝共聚。     

甲基丙烯酸丁酯接枝天然橡胶核壳结构的制备与表征

以过硫酸钾(KPS)为引发剂,采用种子乳液聚合的方法合成了天然橡胶(NR)-g-甲基丙烯酸丁酯(BMA)共聚物。采用正交实验的方法研究了引发剂用量、反应温度、NR/BMA质量比对接枝率和接枝效率的影响,并采用红外(IR)、差示扫描量热法(DSC)以及透射电镜对NR-g-BMA进行了表征。结果显示:当NR/BMA质量比为100/80、KPS用量为0.25 phr(每100 g干基质量)、反应温度为60℃时接枝率和接枝效率最高;红外谱图表明BMA成功接枝到NR分子链上;DSC分析表明NR和PBMA为部分相容体系;TEM观察发现NR-g-BMA胶乳粒子是NR为核,PBMA为壳的核壳结构。按照不同配比制备了甲基丙烯酸丁酯接枝天然橡胶(GNR)与天然橡胶(NR)共混硫化胶膜,并测定了共混硫化胶膜老化前后的力学性能、邵氏硬度A、交联密度。结果表明,GNR/NR硫化胶膜相较于单纯天然橡胶的老化前后的抗拉伸强度及撕裂强度有明显的提高。     

H2S对盐碱混合胁迫下裸燕麦叶片脂肪酸组成的影响

脂肪酸是细胞膜脂的重要组成成分,信号分子硫化氢(H₂S)在植物响应盐碱胁迫中发挥着重要作用。为探讨H₂S对盐碱混合胁迫下裸燕麦脂肪酸组成的效应,采用盆栽砂培试验,研究了外施H₂S供体硫氢化钠(NaHS)和H₂S生成抑制剂羟胺(HA)对50 mmol·L^-1盐碱混合胁迫下裸燕麦品种定莜9号植株生长、叶片细胞膜脂氧化和脂肪酸组成的影响。结果表明：（1）喷施50 μmol·L^-1 NaHS可显著缓解盐碱混合胁迫下定莜9号植株干重的下降和叶片超氧阴离子、过氧化氢和丙二醛含量的提高;增添HA后逆转了喷施NaHS缓解盐碱混合胁迫抑制定莜9号植株生长和叶片膜脂氧化损伤的作用。（2）盐碱混合胁迫导致定莜9号叶片50种脂肪酸中的部分组分含量发生显著改变,使总脂肪酸含量和脂肪酸不饱和程度显著降低。喷施50 μmol·L^-1 NaHS使盐碱混合胁迫下定莜9号叶片5种脂肪酸组分棕榈酸(C16∶0)、岩芹酸 (C18∶1N12)、异油酸(C18∶1N7)、亚油酸(C18∶2N6)和α-亚麻酸(C18∶3N3)含量显著降低,其余45种脂肪酸组分含量变化不大;增添HA后5种脂肪酸月桂酸(C12∶0)、反-10-十五烯酸(C15∶1T)、亚油酸 (C18∶2N6)、α-亚麻酸(C18∶3N3)和二十三烷酸(C23∶0)含量提高,8种脂肪酸硬脂酸(C18∶0)、反异油酸(C18∶1N7T)、岩芹酸(C18∶1N12)、异油酸(C18∶1N7)、顺-11,14-二十碳二烯酸(C20∶2)、HOMO-γ-亚麻酸(C20∶3N6)、神经酸(C24∶1)和顺-7,10,13,16-二十二碳四烯酸(C22∶4)含量下降,其余37种脂肪酸含量无显著变化。（3）喷施50 μmol·L^-1 NaHS显著降低了盐碱混合胁迫下定莜9号叶片饱和脂肪酸、不饱和脂肪酸和总脂肪酸含量及脂肪酸不饱和度和双键指数,添加HA后显著逆转了NaHS降低不饱和脂肪酸和总脂肪酸含量及脂肪酸不饱和度和双键指数的作用。综上所述,H₂S通过降低活性氧积累导致的细胞膜脂氧化损伤和参与脂肪酸组分调控及降低脂肪酸含量和脂肪酸不饱和程度提高裸燕麦适应盐碱胁迫的能力。     

小麦1BL/1RS和7DL·7Ag易位对小麦主要农艺性状的遗传效应

为了解染色体易位对小麦农艺性状的影响,以豫农982(1BL/1RS易位系)和wheatear(7DL.7Ag易位系)杂交后代的900个F2群体及其F2∶3家系为实验材料,对F2群体进行1BL/1RS易位和7DL.7Ag易位类型的分子检测,并对F2群体及F2∶3家系的主要农艺性状进行田间调查(F2群体的农艺性状仅作参考,重点分析F2∶3家系的农艺性状)。结果表明,(1)STS标记Lr19130与SSR引物Xgwm428联合使用可作为共显性标记鉴定纯合与杂合的7DL.7Ag易位,完善了7DL.7Ag易位的分子检测方法;(2)1BL/1RS易位可显著降低株高,提高穗粒数与小穗数;(3)7DL.7Ag易位在籽粒千粒重和饱满度上有显著的正向作用,但7DL.7Ag易位的穗粒数显著低于非7DL.7Ag易位,且有延迟小麦成熟和增加株高的趋势;(4)1BL/1RS和7DL.7Ag双重易位可同时提升小穗数和千粒重,但穗粒数减少。     

不同油酸含量油菜脂肪酸含量分析

为了选育出各脂肪酸的比例及相对含量更加合理的油菜品种,本研究分析了不同油酸含量下7种主要脂肪酸含量间的相关性。除与硬脂酸(相关系数0. 0351)外,油酸与其它脂肪酸基本上呈极显著负相关;除亚麻酸与硬脂酸、芥酸与硬脂酸、花生烯酸与软脂酸、硬脂酸与软脂酸两两呈极显著负相关外,其它均呈极显著正相关。在5677份分析材料中,获得278份油酸含量﹥70%、亚麻酸含量﹤3%、亚麻酸/亚油酸比例大于1∶4的材料,为选育特色油菜品种奠定了基础。     

橡胶树无性系PR107种植密度试验

以橡胶树PR107为试验材料,采用固定行距,由不同的株距形成不同的种植密度,设500,667,833株/hm2 等3种种植密度。结果表明:(1)密度越大,对茎围生长的抑制作用越强烈,其个体间的分化现象也越严重;(2)树龄越长,同一群体内个体间的差异越大;(3)密度越大,单株年产干胶量越低,然而,由于单位面积有效割株与种植密度成正比,种植密度大的单位面积干胶产量也较高,667株/hm2和833株/hm2的单位面积干胶产量极显著高于500株/hm2的,前两者之间无显著差异;(4)种植密度对干胶含量有显著的影响,500株/hm2的干胶含量显著高于667株/hm2和833株/hm2的,后两者之间的干胶含量无显著差异;(5)种植密度在667株/hm2以下时,密度对树皮的生长和再生没有影响,密度达到833株/hm2时,树皮的生长受到明显的抑制;(6)不同种植密度间的风害断倒率和死皮停割率均无显著差异;(7)以提高单位面积干胶产量为主要目的多因素综合考虑,PR107的种植密度应以略低于667株/hm2为宜。      

氮肥用量和基追肥比例对密植秋芝麻产量和冠层结构的影响

为了探索红壤旱地密植秋芝麻的节氮高产栽培技术,以品种金黄麻为材料,采用裂区设计,2016和2017年在江西省进贤县研究氮肥用量[即N_1(105kg/hm^2)和N_2(75kg/hm^2)]和基追肥比例[即Z_1(7∶3)、Z_2(6∶4)、Z_3(5∶5)、Z_4(4∶6)、Z_5(3∶7)]对芝麻产量和冠层结构的影响。结果表明,在N_1条件下,2016年Z_3的单株蒴果数较Z_2显著增加25.36%,Z_4的每蒴粒数和Z_2的千粒重较Z_1的分别显著增加19.96%和13.62%;不同的是,2017年Z_2的每蒴粒数较Z_3显著增加22.84%,对单株蒴果数和千粒重无显著影响。在N_2条件下,2016年Z_3的千粒重较Z_4显著增加6.42%,其它处理间的单株蒴果数、每蒴粒数、千粒重都无显著差异;N_2的平均产量(879.0kg/hm^2)较N_1显著增加22.3%;但是2017年N_1的平均产量(1 080.7kg/hm^2)较N_2增加8.1%。相同的是,两年的结果都表现为Z_2处理平均产量最高。芝麻产量表现为随着基肥的比例减少而先增后减。不同时期N_1的光能截获率和叶面积指数都显著高于N_2,且随生长发育进程而先增后减。不同位置的芝麻冠层光能截获率和叶面积指数都有显著差异,且随着测定位置的不断升高而降低。因此,氮肥用量为75kg/hm^2和基追肥比例为6∶4,有利于协调密植秋芝麻的群体冠层结构,保持秋芝麻的高产。     

丙稀酸甲酯在天然胶乳硫化胶膜表面的接枝共聚

采用氩等离子体激发及紫外辐射引发技术可以使丙稀酸甲酯接枝共聚到天然橡胶硫化胶膜表面。接枝处理硫化胶膜表面接触角测定结果表明,随着接枝反应的进行,较多的聚丙烯酸甲酯接枝到硫化胶膜表面,使硫化胶膜表面接触角显著下降。采用等离子体激发 2 min,紫外光照射 16 min 的处理条件,可使硫化胶膜表面与水的接触角由 105°下降至约 60°。接枝处理硫化胶膜表面形态分析结果表明,接枝后的聚丙烯酸甲酯分子链在硫化胶膜表面互相叠加,使胶膜表面变得粗糙,从而使天然橡胶硫化胶膜表面亲水性能得到改善。     

施氮和黄顶菊混植对大喇叭口期玉米DNA甲基化变异的影响

试验设置4种玉米/黄顶菊混植比例,玉米单种(A1)、玉米/黄顶菊2∶1混种(A2)、玉米/黄顶菊4∶3混种(A3)、玉米/黄顶菊1∶1混种(A4),4种施氮梯度0(CK)、175(T1)、275(T2)、375 kg/hm^2(T3),采用甲基化敏感扩增多态性(Methylation Sensitive Amplification Polymorphism,MSAP)技术,研究不同处理下玉米叶片基因组DNA甲基化的变异特征。结果表明,筛选18对引物组合对各处理玉米叶片进行扩增,不同混植比例下各获得754条MSAP条带,在A1、A2、A3和A4混植比例下,对玉米表观遗传多样性贡献率最大的引物组合分别为EmHM21、EkHM17、EdHM21和EhHM17。A1混植比例下的未甲基化条带数、超甲基化条带数和总甲基化带数与其他3种混植比例条带数相比差异显著,4种混植比例下玉米叶片基因组DNA半甲基化和全甲基化条带数差异不显著,总甲基化条带数为79~93条,占比为10.84%~12.33%。与A1混植比例下相应施氮梯度相比,混植比例达到2∶1(A2)且施氮梯度达到175 kg/hm^2时,玉米叶片的半甲基化水平、全甲基化水平和总甲基化水平产生显著性差异。     

Studies on the utilization of Hura crepitans L. seed oil in the preparation of alkyd resins

The utilization of Hura crepitans seed oil in the formulation of alkyd resins was investigated using a two-stage alcoholysis-polyesterification method. The percentage yield of the oil was 36.4%; and the physicochemical characterization revealed that the seed oil is an unsaturated semi-drying oil. The fatty acid profile of the oil showed that it contains linoleic acid (81.6%) as the most abundant fatty acid, and two other fatty acids: palmitic acid (16.92%) and stearic acid (1.76%). Short (I), medium (II) and long (III) oil alkyds were synthesized using the oil, glycerol and phthalic anhydride in different ratios. Properties of the three prepared samples of H. crepitans seed oil alkyds having oil content of 30% (I), 50% (II), and 65% (III) were evaluated. The alkyd resins synthesized compared favourably with the commercially available alkyd resin. The presence of unsaturation in the oil was confirmed by infra-red peak at 2930 cm⁻¹ attributed to CC stretch. The infra-red peaks of the sample also compared well with that of the commercial sample indicating that H. crepitans seed oil has been successfully converted to alkyd resin. Evaluation of prepared alkyds by determination of acid values, solubility in butanol and toluene, resistance of dry film to acid, alkali and water, and drying time revealed that H. crepitans seed oil is a potential raw material for the coating industry.     

品系对天然橡胶臭氧老化性能的影响

对比分析5个栽培条件相近主栽品系的天然橡胶的结构与性能差异,发现RRIM600性能最好,拉伸强度达30.21 MPa,耐臭氧老化性能最优。通过分析非胶组分,结合ATR-FTIR与热重分析仪器初步探究其耐臭氧老化差异的原因:RRIM600橡胶树生产的橡胶非胶组分杂质与灰分含量低,蛋白质含量适中,P0、PRI较高,分子链结构规整,橡胶中含有较多的胺基抑制臭氧化反应,使得分子链受到保护,综合表现出较好的耐臭氧性能。     

Enzymatic epoxidation of Sapindus mukorossi seed oil by perstearic acid optimized using response surface methodology

As a novel renewable resource, Sapindus mukorossi seed oil (SMSO) with an iodine value of 84.86 g/100 g, and containing 51.0 ± 0.9% oleic acid (18:1), 6.6 ± 0.6% linoleic acid (18:2), 1.1 ± 0.3% linolenic acid (18:3), and 23.1 ± 0.9% eicosanoic acid (20:1), was epoxidized using hydrogen peroxide as oxygen donor and stearic acid as active oxygen carrier in the presence of immobilized Candida antarctica lipase B. The effect of the amount of stearic acid on the enzymatic epoxidation was investigated. Response surface methodology (RSM) was used to study and optimize the effects of variables (reaction temperature, enzyme load, mole ratio of H₂O₂/CC-bonds, and reaction time) on the epoxy oxygen group content (EOC) of epoxidized SMSO. Results showed that stearic acid as active oxygen carrier could enhance the enzymatic epoxidation of SMSO. The variables of reaction temperature and enzyme load were the most significant in the process. A two second-order model was satisfactorily fitted the data (R² = 0.9723) with non-significant lack of fit. The optimum EOC of epoxidized SMSO was 4.6 ± 0.3% under the conditions of 50.0 °C, 7.0 h, 2.00% (relative to the weight of SMSO) enzyme load, and 4:1 mole ratio of H₂O₂/CC-bonds.     

提高印尼20号标准橡胶塑性值的研究

研究了如何提高印尼20号标准天然橡胶塑性值,在印尼广垦橡胶(坤甸)有限公司进行,采用了喷洒草酸、水合联氨等试验方法。结果表明,使用3 %的水合联氨能得到较好的塑性值。     

氮肥运筹模式对冬小麦氮素吸收利用的影响

为给小麦高产、高效、无污染及可持续生产提供合理的氮肥运筹技术和理论依据, 以烟农19为材料,在大田条件下,研究了不同施氮量和基追比例对土壤小麦系统氮素积累及分配的影响。结果表明,施氮可提高0~100 cm土体内的全氮含量。在小麦越冬前, 0~40 cm土层中NO3-N含量随氮肥用量和基肥比例的增加显著增加;起身期到拔节期,施氮量为180和240 kg·hm-2且基肥∶拔节肥∶孕穗肥为3∶5∶2处理的0~40 cm土层内NO3-N含量下降,而施氮量为240 kg·hm-2且基肥∶拔节肥为7∶3和5∶5的处理及施氮量为300 kg·hm-2且基肥∶拔节肥为7∶3的处理则显著增加;拔节期到成熟期,随施氮量的增加,0~60 cm土层速效氮增加幅度有所提高。孕穗肥可明显提高灌浆期的植株全氮含量。因此,在240 kg·hm-2 施氮水平、基肥∶拔节肥∶孕穗肥为3∶5∶2条件下,施氮既能减少土壤硝态氮累积量,又能有效降低土壤硝态氮污染地下水的可能性。     

Effect of gliadin/glutenin ratio on pasting,thermal, and structural properties of wheat starch

Gluten-starch interactions are of specific importance during the processing of cereal-based products. However, the mechanisms for gluten-starch interactions have not been illuminated. The effects of various gliadin/glutenin (gli-glu) ratios (0:10, 3:7, 5:5, 7:3, and 10:0) on the pasting, thermal, and structural properties of wheat gluten-starch mixtures were investigated. The peak, through, and final viscosities were obviously decreased, and the setback value initially increased and then decreased with increasing gli-glu ratios during the rapid viscosity analysis (RVA). Differential scanning calorimetry showed that the enthalpy changes increased with increasing gli-glu ratios. Thermogravimetric analysis showed a slight increase in the degradation temperature of the mixtures as the gli-glu ratio increased, although it was still lower than that of wheat flour. However, there was no significant difference in the weight loss among different gli-glu ratios. Rheometer-Fourier transform infrared (FTIR) spectroscopy showed that the C-6 peak at 996 cm⁻¹ for all the samples was displaced or disappeared due to the hydrogen bond fracture caused by water molecules entering the starch granules. It was also found that the absorption peak in amide II of gli-starch was more obvious than that of glu-starch. The CLSM obviously described the change structure of mixtures with different gli-glu ratio during starch gelatinizaton. By studying the changes in gluten protein components and how they affected the thermal and structural properties of starch, a simple model was proposed to describe the gelatinization process of the mixtures with different ratios of gli-glu and briefly describe the interactions between starch and wheat gluten components. Optimization of the proportion of protein components in wheat flour will enable greater control over the structural characteristics and elasticity of wheat food products.     

Preparation and properties of chitosan–soybean trypsin inhibitor blend film with anti-Aspergillus flavus activity

The chitosan-based blend films were prepared from chitosan, soybean trypsin inhibitor extract (STI)/wild soybean trypsin inhibitor extract (WTI) and glycerol (Gly) solutions, the properties of which were also investigated, including thickness, mechanical property, water vapor transmission, optical transmittance, and solubility. In addition, the resulting films were characterized by scanning electron microscope (SEM), X-ray diffraction (XRD) and Fourier transform infrared spectroscopy (FTIR). The result of SEM images showed the surface and cross-section of chitosan–STI/WTI–Gly blend film had more smooth and dense morphology than pure chitosan film, which suggested there was a better compatibility among the three components. XRD and FTIR spectra indicated that the possible interaction force among the components might be the hydrogen bonds of NH?OC and OH?OC. Furthermore, the antifungal activity against A. flavus by the prepared blend films had been investigated. The facts that the germination and growth of A. flavus were strongly inhibited by chitosan–STI/WTI–Gly film indicated the blend films might be useful as potential bio-control packaging against A. flavus during the peanuts and other cereals storage.     

Spectroscopic comparison of lignin separated by electrolysis and acid precipitation of wheat straw soda black liquor

Electrolysis experiments were carried out with wheat straw soda black liquor. Organics from black liquor were electrodeposited at the anode. These organics were studied for their FTIR and NMR spectra and compared with those separated by acid precipitation of black liquor. The electrodeposited organics were found to be chemically distinct from those obtained by the acidification of the black liquor. Notably, they differed in the characteristic features of the aromatic part from hitherto known lignin formulations as revealed by the absence of signals for quaternary aromatic carbon between δ 129 and δ155 ppm in their ¹³C NMR spectra and higher proportion of aromatic protons in their ¹H NMR spectra. The hydroxyl environment was also found to be different by the shift in OH stretching band to higher frequency. Other significant differences were noted in the FTIR and NMR spectra of the electrodeposited solids from those of acid precipitated solids.     

氮肥施用比例对油菜芝麻复种模式产量和品质的影响

为了探索长江中下游地区旱地油菜芝麻复种模式的高效施肥技术,以华油杂9号和赣芝5号为材料,研究6个氮肥施用比例[P0（油菜:芝麻）=0;P1=157.5:67.5;P2=180.0:45.0;P3=202.5:22.5;P4=225.0:0;P5=180.0:45.0（含油菜枯饼1 500）kg/hm2]对油菜和芝麻产量、品质、氮肥利用率的影响。结果显示,施氮处理的油菜和芝麻总产量都显著高于对照（P0）,但是5个施氮处理间的总产量和氮肥利用率都无显著差异;P3处理总产量（3 053.9kg/hm2）、总效益（25 335.4元/hm2）、氮肥农学利用率（4.1kg/kg）、偏生产力（13.6kg/kg）均最高,其中总产量和总效益较对照（P0）分别显著增加了42.79%和55.08%。油菜主茎籽粒的含油量高于分枝;而籽粒蛋白质含量表现刚好相反,其中主茎的蛋白质含量受氮肥用量影响明显。虽然P3处理的芝麻种子中芝麻素、芝麻林素、芝麻酚含量都较其他处理明显降低,但是油菜和芝麻的含油量与蛋白质含量都保持较高水平。综上所述,当氮肥分配比例为202.5:22.5（kg/hm2）（P3）时,既能够保持较高的油菜和芝麻总产量和氮肥利用率,又具有较优的品质,是减氮条件下油菜芝麻复种模式的适宜氮肥分配比例。