Optimization of extraction method for quantitative analysis of Si/Al in soil phytoliths

Elemental information carried by phytoliths plays a crucial indicative role in geochemical research.For instance,it serves as an indicator of the carbon pool effect in phytoliths and aids in the elucidation of silicon sources.However,early extraction methods for soil phytoliths primarily focused on obtaining their morphological and quantitative information,lacking efficient techniques for quantitative elemental analysis.In this study,we aimed to extract Si/Al information from soil phytoliths.Considering the need for complete extraction of phytolith,six extraction methods were developed and further by alkaline dissolution to determine Si/Al.Six methods were compared in terms of enrichment capacity,the weight of extracted phytoliths,and Si/Al differences.The results indicated that the addition of Ammonia-Catechol in the commonly used heavy liquid flotation method effectively improved phytolith extraction capability and the accuracy of Si/Al results.Additionally,the inclusion of an acetic acid step before alkaline dissolution further removed surface-adsorbed impurities and enhanced the analytical quality of Si/Al in phytolith.The comparison of the data in this study with other published data shows that our method is relatively robust.The improved method proposed in this study can provide a new idea for the quantitative analysis of other elements in soil phytoliths.

Screening of Extraction Methods for Protein from Potato Tubers

[Objectives]This study was conducted to screen different extraction methods for protein from potato tubers.[Methods]The bud eye,lateral and pith parts of Qingshu 168 and Kexin 1 were used as test materials,and were extracted by acetone extraction,trichloroacetic acid(TCA)extraction,salt extraction,alcohol extraction and phenol extraction,respectively.The protein contents of different parts were determined by spectrophotometry.A 2-factor randomized block design was used to study the effects of varieties,extraction methods,sampling parts and combinations of different factors on protein content.[Results]The protein contents of different varieties were different,and Qingshu 168 was significantly higher than Kexin 1(P<0.05),reaching 128.0 mg/L.The protein contents obtained by different extraction methods were different.Acetone extraction,salt extraction and TCA extraction showed no significant differences in the protein content,but they were significantly higher than phenol extraction and alcohol extraction(P<0.05).The protein contents obtained by the former three were in the range of153.3-159.7 mg/L.The protein content in the bud eye part of potato tubers was significantly higher than those in the lateral and pith parts(P<0.05),reaching140.7 mg/L.There were significant differences among different combinations of varieties,extraction methods and sampling parts(P<0.05).The comprehensive comparison showed that the salt extraction method was suitable for the bud eye part of Qingshu 168,and the TCA extraction method was suitable for the bud eye part of Kexin No.1.[Conclusions]This study provides a reference for potato protein extraction and further research.

An Experimental Method to Quantify Extractable Amino Acids in Soils from Southeast China

The extraction and comparison of soil amino acids using different extractants （deionized water, K2SO4, Na2SO4, NaC1, KCI） were reported. Results showed that 0.5 tool L-1 K2SOa with a 5 times extraction was a better method to assess the concentration of extractable amino acids in soils. The total amino acids extracted from soil planted for tea were similar to the total inorganic nitrogen. While they extracted from vegetable soil and paddy soil were much lower than the total inorganic nitrogen.

Evaluation of Cadmium Bioavailability in Soils Using Diffusive Gradients in Thin Film Technique and Traditional Methods

The developed technique of diffusive gradients in thin film( DGT) has been suggested as a promising tool for evaluation of cadmium( Cd) availability in soils,but there exists considerable debate on its suitability. In this study,Cd bioavailability in soils was systemically investigated by comparing this technique with seven traditional methods, including soil solution concentration and six commonly used extraction methods( HAc,EDTA,Na c,NH4Ac,CaCl2 and MgCl2). Two typical plants( wheat and maize) were examined for Cd uptake. Maize was more sensitive to increasing exposure to Cd in soils than wheat when the added amounts of Cd ranged from 3. 5 to 5. 0 mg · kg-1,accompanied by the significant decreases of shoot and root biomasses. Cd concentrations in shoots and roots of two plants increased continuously with increasing levels of Cd in soils. Cd uptake was higher in wheat than that in maize. The bioavailable concentrations of Cd measured by all methods increased nearly linearly with increasing addition of Cd in soils. Positive correlations were observed between various bioavailable indicators of Cd in soils and Cd concentrations in two plants. The extractable Cd by six chemical extractants was considerably higher for maize than for wheat,while the DGT-measured and soil solution concentrations of Cd were lower for maize than for wheat,following the same trend as plant Cd uptake. The results imply that DGT measurement can effectively predict the bioavailable levels of Cd in soil solutions and that it is an ideal tool for prediction of Cd bioavailability in soils.

Peanut proteins:Extraction,modifications,and applications:A comprehensive review

As naturally sourced proteins,peanut proteins have garnered significant attention from the food industry,owing to their numerous advantages,such as easy extraction,non-pungency,and high bioavailability.Furthermore,peanut proteins are highly digestible in the gastrointestinal tract and boast a high net protein utilization rate,making them an appealing protein source in food products and a promising alternative to animal protein.In this paper,the recent works on the extraction method,modification method,and application of peanut proteins were reviewed.Both advantages and disadvantages of current extraction and modification were discussed.Recently updated information about peanut protein research was summarized.Based on these,the prospection of peanut proteins research was presented,which may be instructive for future research in this field.Future research is still needed for accessible modification methods to develop the functional properties of peanut proteins.

Liquid-liquid extraction pretreatment samples method used for pharmacokinetic study of rhubarb in rats after oral administrated

Objective:Pretreatment of biological samples is the most critical step in pharmacokinetic studies,especially pre-treatment of plasma samples.The pretreatment of biological samples in pharmacokinetic study of Traditional Chinese Medicines (TCM) is difficult due to the complexity of the ingredients.An organic solvent system ethyl acetate:acetone (10:1) solution used for liquid-liquid extraction has been developed in this study and compared with the commonly used protein precipitation method.Methods:Rats,Beagle dogs and humans plasma samples were adopted in this study in order to demonstrate the universality of the pretreatment method.Feasibility of this pretreatment method was also verified through its application to the pharmacokinetics of rhubarb in rats.Results:According to the results of extraction recovery matrix effect,it was indicated that the liquid-liquid extraction methods with new organic solvent might be suitable for variety of structures of compounds and various types of plasma samples.The pharmacokinetic study result showed that the developed pretreatment method could successfully be used for simultaneous determination of three active compounds modin,emodin-8-O-β-D-glucopyranoside (EDG) and rhein in rat plasma with high sensitivity,accuracy,and recovery by liquid chromatography tandem mass spectrometry (LC-MS/MS).Conclusion:The pretreatment method of liquid-liquid extraction methods with new organic solvent could be successfully applied for multi-component pharmacokinetics of TCM.

Effects of long-term phosphorus fertilization and straw incorporation on phosphorus fractions in subtropical paddy soil

Study on soil phosphorus（P） fraction is an important aspect in probing the mechanisms of soil P accumulation in farmland and mitigating its losing risk to the environment. We used a sequential extraction method to evaluate the impacts of long-term fertilization and straw incorporation on inorganic, organic, and residual P（Pi, Po, and Pre） fractions in the plow layer（0–20 cm） of acidic paddy soil in southern China. The experiment comprised of six treatments：（i） no fertilizer control（CK）;（ii） straw incorporation and green manure（SG）;（iii） nitrogen and P fertilizer（NP）;（iv） NP＋SG;（v） NP＋K fertilizer（NPK）; and（vi） NPK＋SG. The results showed that, compared to the initial total soil P content（TSP, 600 mg kg^–1 in 1990）, long-term（20 years） combined continuous P fertilizer and SG significantly increased P accumulation（by 13–20%） while single fertilization（39.3 kg P ha^–1 yr^–1） could maintain soil P status at the most. The average soil P fractions comprised of extractable Pi, Po, and Pre by 51.7, 33.4, and 14.9% in total soil P, respectively. With comparison of no fertilizer addition（CK）, long-term single fertilization significantly（P〈0.05） increased the accumulation of Na HCO3^–, Na OH^–, and HCl^– extractable Pi fractions accounting for two- to three-fold, while SG increased the accumulation of Na HCO3^– and Na OH^– extractable Piand Po accounting for 12–60%. Though the mobilization of Pre fractions was not significant（P〉0.05）, our data indicate that SG may partially substitute for fertilizer P input and minimizing soil P accumulation and subsequent environmental risk in the subtropical paddy soil.

Modeling of seasonal soil cold storage using natural cold energy

To reduce energy consumption on summer air conditioning,a novel seasonal soil cold storage mode using natural energy is presented and two-dimensional transient heat transfer model of U-tube is developed. The three processes of cold storage in winter,shut-down in transition season and cold extraction in summer are simulated by using sensitive heat capacity method with variable time step. The changing of U-tube outlet water temperature in different periods,daily cold storage and cold extraction are estimated. The temperature field of the U-tube and soil around the tube is investigated. Simulations show that seasonal soil cold storage using natural cold energy is feasible in the north to Changchun,which provides theoretical support for seasonal soil cold storage application.

Extraction-Atomic-Absorption Determination of Gallium (III) with 2-hydroxy-5-T-butylphenol-4’-methoxy-azobenzene

The complexation of gallium with 2-hydroxy-5-T-butylphenol-4’-methoxy-azobenzene (HR) has been studied by atomic absorption and spectrophotometric methods. The optimal conditions for the formation and extraction of the complex were found. The maximum light absorption of the complex in n-butanol is in the range of 450 - 470 nm. The molar absorption coefficient is (3.3 - 4.2)⋅104. The stability constant of the gallium coordination compound in n-butanol is βl = 4.2⋅1010. The developed technique allows to determine the gallium content within n × 10−1 - n × 10−4%. The selective and sensitive technique for the extraction-atomic absorption determination of gallium in soils has been developed.

土壤有效硼提取及测定方法比较

本文提出一种沸水浴提取–ICP-OES测定土壤有效硼的方法,并着重比较分析沸水提取–姜黄素比色法、沸水提取–ICP-OES法、沸水浴提取–ICP-OES法和沸水浴提取–姜黄素比色法对土壤有效硼的测定结果。通过讨论4种方法的测定下限、方法检出限和测定精密度及正确度,及对来自不同地区高中低有效硼含量的6种土壤有效态成分标准物质和4种实际土壤样品的测定比较,探讨4种方法分析测定的关键因素、方法相关性。结果表明,沸水浴提取–ICP-OES法操作简单便捷,方法的检测下限低、干扰因素少、重复性好,可适用于各类型批量样品分析及研究。本研究可为实验室开展土壤有效硼测定方法研究提供借鉴,也可为承担“第三次全国土壤普查”土样检测的实验室在土壤有效硼测定的方法选择、效率提升和质量保证上提供技术支撑。

自升式钻井平台插拔桩对邻近平台变形和桩靴承载力的影响研究

自升式钻井平台桩靴插拔过程会扰动周边土体,使邻近平台桩靴基础的承载性能受到不利影响。基于弹性理论,求解桩靴脚印周边土体卸荷程度与影响范围,结合模型试验,揭示距插拔位置不同距离/直径(L/D)条件下土体强度的衰减规律;利用CEL大变形和桩靴脚印拟静力计算方法,分析某油田的自升式钻井平台桩靴插拔过程,揭示桩靴插拔对周边土体应力、邻近平台变形和桩靴承载力的影响规律。

三重指数裸土信息提取优化方法及其应用

快速、准确、简便地提取裸土信息对高效监测水土流失状况、科学开展水土保持工作具有重要意义。本研究以福建省长汀县为研究区域,构建了三重指数裸土信息的遥感提取方法,选取裸土指数BI初步提取裸土信息,再利用垂直不透水面指数PISI和仿归一化建筑指数NDBI*剔除裸土中混杂的建筑用地。将三重指数法应用于长汀县的结果表明:①长汀县裸土面积从2016年的128.61km^(2)下降至2022年的102.22km^(2),反映出该县水土保持工作的良好成效。②三重指数法操作简便,并且在分离裸土和建筑用地信息上有较好的表现,提取总精度在96%以上,Kappa系数大于0.89。

核桃蛋白的结构、营养价值、制备、功能特性及在食品中的应用

我国核桃年产量479.59万t,位居全球第一。核桃营养价值丰富,核桃仁中油脂和蛋白质的含量分别为65%~69%和15%~20%。核桃制油后的副产物饼粕资源丰富,但其加工效益低,主要用于饲料和肥料,高值化利用潜力未被发掘。研究发现核桃饼粕中含有大量的蛋白质(42%~54%),且其氨基酸组成丰富、比例适宜人体吸收,蛋白质的真实消化率为86.22%,生物价可达98.77%,是一种优质植物蛋白。因此,高效利用核桃饼粕中的蛋白质资源是提升其高值化利用的重要途径。本文综述了核桃蛋白的组成、结构和营养价值,概述了核桃蛋白的制备方法和功能特性,总结了修饰改性对其功能特性和消化率的影响,并介绍了核桃蛋白在食品中的应用潜力。

核桃蛋白提取方法研究进展

核桃粕是核桃榨油后的副产物,富含蛋白质,核桃蛋白中必需氨基酸含量较高,成分均衡,是成人必需氨基酸的良好来源。核桃蛋白传统提取方法主要为碱溶酸沉法,随着提取设备及提取技术的进步,更多的新型方法及组合方式被开发且证实优于传统方法。然而,采用不同的方法提取核桃蛋白的提取率、纯度,以及结构和功能性质存在显著差异。因此本文重点介绍了具有潜在产业化应用价值的核桃蛋白提取方法,包括碱溶酸沉法、超声辅助、酶辅助以及反胶束法,阐述了不同提取方法对核桃蛋白质结构及功能的影响,并对其应用前景进行了展望,旨在为核桃蛋白质资源的深入研究及开发提供参考。

芸豆蛋白功能特性及改性的研究进展

芸豆是中国传统豆类资源的一种,芸豆的营养组成较为全面,芸豆蛋白所含的氨基酸种类齐全,必需氨基酸含量较高。芸豆蛋白的功能特性在植物蛋白中具有优势,但相关研究和综述尚且较少。该文对芸豆蛋白的提取方法、功能特性和改性研究进行了综述,着重阐述了芸豆蛋白的各种功能特性以及不同改性方法对其功能特性的影响。针对芸豆蛋白的利用率较低、高附加值产品稀缺的技术难题提出展望,为提高芸豆蛋白的加工实用性及扩大其应用范围提供理论支撑。

石灰土易提取球囊霉素相关土壤蛋白的实验条件优化

在水-二氧化碳-碳酸盐岩-生物的相互作用下,全球形成8.24×10^(8)t C/a的岩溶碳汇,其中部分岩溶碳汇以土壤有机质的形式固存,进而在国家双碳目标中发挥重要作用。全球分布广泛的丛枝菌根真菌分泌的球囊霉素相关土壤蛋白(Glomalin-related soil protein,GRSP)性质稳定、不易分解,是土壤有机质的重要组成部分。提取合格的GRSP是深入研究岩溶土壤有机碳汇的基础,然而以往研究因GRSP提取量不高、提取不充分、产物不专一等问题,以至其在有机质中发挥的作用机制无法深入开展研究,因此,提高GRSP提取量对于探究岩溶土壤有机质的形成和稳定机制具有重要意义。本文选取岩溶区黑色、棕色、黄色和红色四种石灰土,通过温度和时间正交实验,筛选出适用于岩溶土壤颗粒态有机质(POM)和矿物结合态有机质(MAOM)易提取球囊霉素相关土壤蛋白(EE-GRSP)的最佳提取条件。实验结果表明,POM和MAOM在123℃和80min条件下提取时,EE-GRSP提取量最高。应用于四类石灰土后,EE-GRSP增量范围为4.6%~34.2%。相较于全土,MAOM具有更高的稳定性与更强的有机碳保护能力。因此,随着温度和提取时间的提高,MAOM中的EE-GRSP得到更完全的释放,提取量显著提高。由此可见,EE-GRSP提取条件优化对深入研究岩溶土壤碳汇潜力及其稳定机制具有重要意义。

基于作物Cd富集系数的土壤有效态Cd化学浸提方法筛选

土壤中镉(Cd)被作物吸收的程度及其生态风险取决于土壤中Cd的赋存形态,基于Cd有效形态的污染土壤风险评价及在此基础上制订污染土壤修复安全阈值是Cd污染农田土壤风险评价和治理亟待解决的问题。目前针对土壤中重金属有效态的化学浸提方法较多,但缺乏针对不同性质土壤中有效态Cd的普适性浸提方法已成为Cd污染土壤风险评价技术瓶颈。本研究采集了全国9个不同性质农田土壤,以水稻、小白菜和玉米为测试作物,通过外源添加方法制备Cd污染土壤,结合土壤培养和盆栽实验,测定了5种常用化学浸提方法,包括中性无机盐浸提方法(CaCl_(2)浸提法)、弱酸浸提法(HCl浸提法)、络合螯合剂浸提方法(DTPA和ETPA浸提法)和组合浸提方法(Mehlich-3(M3)浸提法)对不同性质土壤中有效态Cd浸提效果及其与作物Cd吸收的量化关系,筛选适用于不同性质土壤中有效态Cd的通用浸提方法。结果表明,不同化学浸提法提取的土壤有效态Cd含量间具有显著差异,不同浸提方法对土壤中Cd的浸提率(%)为DTPA≈EDTA≈HCl>M3≈CaCl_(2)。不同化学浸提态Cd与作物Cd吸收的相关系数间具有显著差异,基于综合相关系数方法,得出5种不同浸提态Cd与作物Cd吸收的综合相关系数为I M3=0.765,I EDTA=0.641,I DTPA=0.627,I HCl=0.606,I CaCl_(2)=0.711,M3浸提态Cd含量与不同性质土壤中水稻、小白菜和玉米植株地上部Cd相关性最高,可作为不同性质土壤中有效态Cd通用浸提方法。相关研究结果可为农田土壤中Cd有效态评价及Cd污染农田的修复提供理论依据。

物理场耦合水酶法同步释放植物油和蛋白的研究进展

水酶法同步释放油和蛋白是一种新兴的提取技术,绿色清洁、能满足可持续发展的社会要求,物理场和水酶法耦合作用可促进油和蛋白的释放,逐渐成为研究热点。该文综述了物理耦合水酶法的技术原理和优势、同步释放油和蛋白的研究进展,同时综述了该技术对油料中蛋白特性的影响,并对目前存在的问题以及未来的发展进行了展望。

不同提取方法提取马铃薯蛋白的研究

该实验以新鲜马铃薯为原料,采用醇溶法、盐溶法、碱溶法3种方法提取马铃薯蛋白,测定其纯度和提取率,结果表明,醇溶法提取的马铃薯蛋白纯度为94.5%,提取率为4.5%,提取效果最好。通过SDS-PAGE电泳分析,醇溶法提取的马铃薯蛋白亚基条带多,分子量范围广,并且在分子量为25~40 kDa范围内含量很高,说明醇溶法能有效提取马铃薯蛋白质的各个组分;进一步研究其理化性质,发现醇溶法提取的蛋白质持油性、持水性、乳化性、乳化稳定性更好;水解度分析显示醇溶法提取的马铃薯蛋白水解度更高。因此,在这3种方法中,醇溶法是比较经济、所得蛋白质性质较好的提取方法。

花椒籽蛋白的制备工艺优化及组成分析

以花椒籽蛋白提取率为评价指标,采用单因素试验和响应面试验研究4个因素(料液比、pH值、提取温度和提取时间)对花椒籽蛋白提取率的影响。通过SDS-PAGE凝胶电泳和氨基酸分析,探究花椒籽蛋白的组成。结果表明,花椒籽蛋白的最佳提取工艺条件为料液比1∶35(g/mL)、pH值9.0、提取温度45℃、提取时间3.5 h,在该条件下花椒籽蛋白提取率可达46.54%。花椒籽蛋白由6个主要亚基组成:54,31,25,18,10,9 kDa,其中31 kDa的蛋白质含量最丰富。花椒籽蛋白氨基酸种类齐全,其中Glu含量最高,达到16.37 g/100 g。此外,花椒籽蛋白中必需氨基酸、疏水性氨基酸和酸性氨基酸含量较高,分别为36.88,34.75,24.65 g/100 g。由此可知,花椒籽蛋白是一种营养价值较高的优质蛋白质资源,同时可能具备抗氧化功能。