离子交换法制备低植酸含量大豆蛋白的研究

大豆食品中的植酸会阻碍多种矿物离子及蛋白的吸收,为了提高大豆蛋白的营养吸收性,加工中应去除植酸。本文研究了离子交换法脱除大豆分离蛋白中植酸的方法和效果,并进一步考察了处理后大豆蛋白的理化性质。结果表明:透析、超滤与离子交换法进行比较,阴离子交换后植酸含量下降77%,较优于其他方法。后采用离子交换法去除大豆蛋白中的植酸,对不同树脂、不同蛋白状态及酸碱度对植酸的去除效果进行比较,以确定植酸去除的最优方案。与其他树脂相比,D201树脂对植酸的吸附率达到12 mg·m L-1,在p H7.0的条件下可将植酸含量降低到1 mg·g-1,下降约90%。制备的低植酸含量的大豆蛋白等电点向右偏移,溶解性略有下降,分散速度有所提高。     

The removal of heavy metals in aqueous solution by hydroxyapatite/cellulose composite

Hydroxyapatite has an excellent ion-exchangeability and is expected to be used as an agent for the removal of heavy metal ions in wastewater. However, the pure hydroxyapatite is very difficult to use because it exists in the form of white powder. Thus, the pure hydroxyapatite was mixed with cellulose to utilize its ion-exchangeability. In this research, a method for dispersion of hydroxyapatite in cellulose matrix is described and its dispersion is observed with scanning electron microscopy. The removal ratios of some heavy metal ions with hydroxyapatite composite are examined with regard to reaction time and amount of hydroxyapatite composite. The ion-exchangeability of hydroxyapatite composite did not seem to be interfered by cellulose matrix during removing heavy metal ions.     

Removal of some cationic dyes from aqueous solution by acrylamide- or 2-hydroxyethyl methacrylate-based copolymeric hydrogels

In this study, anionic hydrogels were prepared using a crosslinker (N,N′-methylenebisacrylamide) through a free radical addition reaction in aqueous solutions of neutral acrylamide or 2-hydroxyethyl methacrylate monomer and anionic monomers, mesaconic acid or aconitic acid. Cationic dyes along with safranine (azine-), nile blue (oxazine-) and methylene blue (thiazine-) were selected as models of pollutants, and adsorption of these dyes onto the hydrogels was investigated. To examine the effect of concentration on adsorption, dye solutions prepared with a concentration range of 5–50 mg l^?1 and 0.1 g hydrogel at 25 °C were exposed to the hydrogels until equilibrium was established. Dye adsorption onto the hydrogels was found to be an L type Giles adsorption isotherm. Monolayer sorption capacity and adsorption constant values were calculated from the Langmuir plots. To calculate R_L values, a non-dimensional analysis was used and they were always found to be 0<R<1. In other words, the hydrogels were favorable for adsorption of these dyes. Aqueous solutions of dyes were observed to interact with hydrogels in the following order: oxazine > azine > thiazine. Furthermore, the higher the number of carboxyl groups in the hydrogel composition, the higher the adsorbed amount of substance.     

离子对色谱法测定茶叶中的茶氨酸

通过添加十二烷基磺酸钠(SDS)为离子对试剂,以乙腈-水(磷酸)为流动相,在200nm的检测波长条件下,建立了一种快速测定茶叶中茶氨酸的分析方法。茶氨酸的保留时间为6.27min;在0.04~20μg范围内,茶氨酸峰面积与进样量之间有良好的线性关系,回归方程为:Y=1.51466×106X+3.28706×105(r2=0.99901);当S/N=3时,最低检测浓度为1.15ng。所建方法快速,简便,准确,可用于茶叶中茶氨酸含量测定。     

Sorption potential of modified nanocrystals for the removal of aromatic organic pollutant from aqueous solution

Chemically modified starch nanocrystals were used as adsorbents for the removal of aromatic organic compounds from water. The nanocrystals were chemically modified by grafting with stearate moieties which enhanced the adsorption capacity of the nanometric substrate. Their adsorption capacity ranged between 150 and 900 μmol g⁻¹ of modified nanoparticles and the adsorption isotherms could be described accurately by the Langmuir model. The adsorption kinetics followed a two-step process with first pure adsorption of the aromatic compounds onto the surface of the nanoparticles followed by a diffusion of the compounds into the layer of surface chains grafted onto the nanoparticles. Furthermore, the feasibility of using these nanoparticles in continuous flow mode processes was confirmed using a fixed bed column setup. The fixed bed column could also be regenerated by washing with ethanol and was found not to exhibit any loss in adsorption capacity over multiples adsorption-desorption cycles.     

离子注入后的甜菊种子电导率及发芽能力变化

以氮、碳离子注入甜菊种子研究其电导率、ｐＨ值及发芽能力的变化，结果表明，被处理种子的电导卓，随着浸种时间的延长而提高，以注入能量７５ｋｅＶ与剂量１０１４最为敏感，氮离子比碳离子对电导率的影响作用更大；离子注入甜菊种子后，ｐＨ值均在４．５～５．０之间，碳离子稍高于氮离子，能量与剂量的变化反应不敏感；离子注入后甜菊种子的发芽势与发芽率有相同趋势，小剂量、低能量促进种子发芽，碳离子比氦离子作用更为明显。     

离子注入介导大豆DNA转化普通小麦的影响因素

为了研究离子注入介导大豆DNA转化普通小麦的影响因素，选择受体小麦品种、供体大豆品种、DNA浓度、浸泡时间4个因素各4个水平进行正交试验。结果表明，影响转化效果的顺序为：受体小麦品种〉供体大豆品种〉浸泡时间〉DNA浓度。4个受体小麦品种中，豫农92349后代高蛋白椿率最高，是优良的受体;4个供体大豆品种中，郑14青豆是较好的供体；在4个浸泡时间中，浸泡时间为48h的转化效果最好；4个DNA浓度水平中，浓度为200μg／mL的转化效果最好。方差分析表明，受体小麦品种对转化效果的影响较大，达极显著水平，其余三个因素对转化效果的影响较小。     

离子色谱法测定贮藏期间菠萝果实的有机酸变化

采用离子色谱法对贮藏期间菠萝(品种‘巴厘’)果实中的有机酸进行有效分离与测定,分析条件为:IonPacAS11-HC(4×250 mm)阴离子分离柱,柱温30℃,抑制型电导检测器,NaOH溶液作为淋洗液进行梯度测试,流速1.5 mL/min。结果表明,菠萝果实中的有机酸以柠檬酸为主,其次为苹果酸,且贮藏期间柠檬酸和总酸的含量呈先上升再下降的趋势。     

Preparation of regenerated cellulose fiber via carbonation. I. Carbonation and dissolution in an aqueous NaOH solution

Cellulose carbonate was prepared by the reaction of cellulose pulp and CO₂ with treatment reagents, such as aqueous ZnCl₂ (20–40 wt%) solution, acetone or ethyl acetate, at −5–0°C and 30–40 bar (CO₂) for 2 hr. Among the treatment reagents, ethyl acetate was the most effective. Cellulose carbonate was dissolved in 10% sodium hydroxide solution containing zinc oxide up to 3 wt% at −5–0°C. Intrinsic viscosities of raw cellulose and cellulose carbonate were measured with an Ubbelohde viscometer using 0.5 M cupriethylenediamine hydroxide (cuen) as a solvent at 20°C according to ASTM D1795 method. The molecular weight of cellulose was rarely changed by carbonation. Solubility of cellulose carbonate was tested by optical microscopic observation, UV absorbance and viscosity measurement. Phase diagram of cellulose carbonate was obtained by combining the results of solubility evaluation. Maximum concentration of cellulose carbonate for soluble zone was increased with increasing zinc oxide content. Cellulose carbonate solution in good soluble zone was transparent and showed the lowest absorbance and the highest viscosity. The cellulose carbonate and its solution were stable in refrigerator (−5°C and atmospheric pressure).     

离子束介导大豆DNA转入普通小麦后代的麦谷蛋白和醇溶蛋白分析

为了研究离子束介导大豆DNA转入普通小麦的效果,应用SDS-PAGE和A-PAGE电泳分析了离子注入介导大豆DNA转入普通小麦后代中高蛋白含量植株的麦谷蛋白和醇溶蛋白。SDS-PAGE电泳结果表明,与对照相比有8个高蛋白含量植株的HMW-GS谱带数目发生了变化或着色增强。A-PAGE电泳结果表明,与对照相比有9个高蛋白含量植株的醇溶蛋白谱带数目及着色强度发生了变化。说明离子束介导大豆DNA转入普通小麦后代中的高蛋白含量植株在醇溶蛋白和麦谷蛋白基因位点上可能出现了变异。     

非衍生化-气相色谱串级质谱（GC-MS-MS）法测定豆粉中的三聚氰胺

利用离子阱气相色谱质谱联用仪,建立了非衍生化处理-气相色谱串级质谱直接分析三聚氰胺的检测方法.利用三聚氰胺二级质谱进行定性,以二级质谱的特征离子峰m/z=85进行定量,分析效率大大提高.方法的线性范围为0.5～10 mg/L,线性相关系数为0.998 7,最小检测限为0.20 mg/kg,方法的精密度为5.9%,方法的回收率为82%～96%,满足现有三聚氰胺的检测,建立的方法可以直接应用于该类产品中三聚氰胺的检测.     

阴离子交换富集ICP-AES法测定海水中的重金属元素

采用321型和717型阴离子混合交换树脂对海水中的重金属元素Cd、Cr、Pb、Cu、Ni和Zn进行分离预富集,以10%的硝酸溶液洗脱,ICP-AES法直接测定。结果表明,Cd、Cr、Pb、Cu、Ni和Zn能同时被阴离子交换树脂定量吸附。方法加标回收率在90.4%～105.8%,测定结果的相对标准偏差为0.96%～3.96%,方法的检出限为Cd 0.12、Cr 0.46、Pb 0.98、Cu 0.65、Ni 0.57和Zn 0.82 μg/L 。在优化的实验条件下,方法有较低的检出限,并且准确度和精密度令人满意。     

应用离子交换树脂球研究温度对水稻土养分释放动态的影响

采用”通用佳”离子交换树脂球法研究了3种不同温度下（15℃、25℃、35℃）淹水土壤氮、磷、钾、钙、镁等养分释放的动态规律。结果表明,温度升高对土壤氮和磷释放有明显的促进作用。7周内离子交换树脂对N的累积提取量,25℃和35℃时比15℃分别增加了91%和189％;同期对P的累积提取量25℃和35℃时比15℃分别增加了131%和393％;温度对土壤钾钙镁释放的影响相对较小。不同温度下土壤养分释放动态适合于乘幂方程RAQ（i,t）=atb,其中,RAQ（i,t）表示树脂球t天内所吸收的i养分离子量(μmol/cm[sup]2[/sup]),a、b为常数,t为培养时间。     

Exogenous ascorbic acid scarcely ameliorates inhibition of photosynthesis in rice leaves by O3

The role of ascorbic acid on acute O₃-induced inhibition of photosynthesis in solution-cultured paddy rice was evaluated. As pre-treatment, ascorbic acid (0, 5, and 10 mM) was added to the culture solution for 5 d before 5 h of O₃ exposure (0, .1, and .3 cm³ m^?3 O₃) during daytime. O₃ decreased photosynthesis-related parameters, total ascorbic acid content, and the redox state (RDS) of ascorbic acid. Ascorbic acid treatment enhanced the total ascorbic acid contents and its RDS level of rice leaves, but scarcely ameliorated O₃-induced inhibition of photosynthesis-related parameters. Inhibition of net photosynthetic rate (P_N) by O₃ was slightly ameliorated by exogenous ascorbic acid only at 1 d after O₃ exposure. These results indicate that ascorbic acid is a component of protection from O₃ injury but has a marginal role in the acute inhibition of P_N by O₃ in rice leaves.     

Preparation of shikonin by hydrolyzing ester derivatives using basic anion ion exchange resin as solid catalyst

An efficient catalytic hydrolysis approach was developed to prepare shikonin from its ester derivatives with anion exchange resins as solid catalyst. The performance of seven anion exchange resins including D290, D296, D261, D280, 201×7, D301-G and D301-R has been evaluated. The research results indicate that D290 resin is the most appropriate for preparation of shikonin. The reaction conditions such as reaction temperature, reaction time, catalyst amount and catalyst reuse have been studied. The maximum yield of shikonin reached 93.74 ± 2.99% under optimal conditions of hydrolysis temperature 20 °C, hydrolysis and desorption time both 30 min and resin amount 10% (w/v). HPLC chromatograms of samples, obtained after the new catalytic process, demonstrated that conversion of shikonin ester derivatives into shikonin performed well.     

The quality of tomato for canning as affected by combined chloride,nitrate and osmotic potential of the nutrient solution

The quality of tomato fruit and juice (Lycopersicon esculentum L. cv. VF M82-1-8) grown in an aerohydroponic system in a greenhouse was affected by the level of Cl^– and NO ₃ ^– , and by the osrnotic potential (OP) of the nutrient solutions. The total suspended solids (degrees Brix) in the fresh juice increased from approximately 4.0 in the nonsaline solutions (OP –0.05 MPa) to approximately 5.6–5.8 in the saline solutions (OP –0.45 MPa). Juice acidity was similarly affected by the Cl^–, NO ₃ ^– and OP levels in the nutrient solutions. Less affected, the ascorbic acid content of juice, was lowest ( 8–9 mg/100 cc) in the high-NO ₃ ^– -nonsaline solution treatments, and was between 10 and 12 mg/100 cc at OP levels greater than –0.2 MPa. NO ₃ ^– in the juice was high ( 60 mg/L) under low OP conditions ( –0.05 to –0.1 MPa), especially when combined with high NO ₃ ^– levels, and lower (between 8 and 30 mg/L) in plants exposed to saline conditions (low OP). Fruit puffiness (boxiness) was reduced markedly by salinity and was not considerably affected by the NO ₃ ^– /Cl^– ratio, while fruit firmness was influenced by both factors.Contribution from the Agricultural Research Organization (ARO), The Volcani Center, Bet Dagan, Israel.     

Suppression of green peach aphid (Myzus persicae) (Sulz.), citrus mealybug (Planococcus citri) (Risso), and two spotted spider mite (Tetranychus urticae) (Koch.) attacks on tomatoes and cucumbers by aqueous extracts from vermicomposts

Vermicomposts are produced through interactions between earthworms and microorganisms in the breakdown of organic wastes. Aqueous extracts were prepared in commercial brewing equipment (Growing Solutions Inc.) from vermicomposts processed from pre-consumer food waste. The ratio of vermicompost to water was 1 to 5 v:v to produce a 20% aqueous solution. The effects of soil drenches at dilutions of 20%, 10%, and 5% vermicompost extracts, were compared with those of deionized water, in the suppression of green peach aphids, mealybugs, and two spotted spider mites attacking tomatoes and cucumbers, in greenhouse cage experiments.