Green Synthesis of Silver Nanoparticles Using Aqueous Orange and Lemon Peel Extract and Evaluation of Their Antimicrobial Properties

Green synthesis of silver nanoparticles (AgNPs) using aqueous extracts of orange and lemon peels, as a reducing agent, and silver nitrate salts as a source of silver ions is a promising field of research due to the versatility of biomedical applications of metal nanoparticles. In this paper, AgNPs were synthetized at different reaction parameters such as the type and concentration of the extracts, metal salt concentration, temperature, speed stirring, and pH. The antibacterial properties of the obtained silver nanoparticles against E. coli, as well as the physical and chemical characteristics of the synthesized silver nanoparticles, were investigated. UV-Vis spectroscopy was used to confirm the formation of AgNPs. In addition to green biogenic synthesis, chemical synthesis of silver nanoparticles was also carried out. The optimal temperature for extraction was 65˚C, while for the synthesis of AgNPs was 35˚C. The synthesis is carried out in an acidic environment (pH = 4.7 orange and pH = 3.8 lemon), neutral (pH = 7) and alkaline (pH = 10), then for different concentrations of silver nitrate solution (0.5 mM - 1 mM), optimal time duration of the reaction was 60 min and optimal stirring speed rotation was 250 rpm on the magnetic stirrer. The physical properties of the synthesized silver nanoparticles (conductivity, density and refractive index) were also studied, and the passage of laser light through the obtained solution and distilled water was compared. Positive inhibitory effect on the growth of new Escherichia coli colonies have shown AgNPs synthesized at a basic pH value and at a 0.1 mM AgNO3 using orange or lemon peel extract, while for a 0.5 mM AgNO3 using lemon peel extract.

Study on Extraction of Pectin from Orange Peels

The comparison was conducted to investigate the higher extraction rate between two methods including alcohol deposition with acid hydrolysis and micro- wave-assistant extraction technique. The experimental results showed that the former method led to a better extraction effect. For the method of alcohol deposition with acid hydrolysis, the technique parameters were optimized through I.s （34 ） orthogonal e^periment based on the results of single factor experiments, after investi- gated the effect of solid to liquid ratio, pH, extraction temperature and extraction time on the pectin extraction rate. tersrm technique was employed to extract pectin. The selected parameter was obtained by means On the basis of the optimal technical parmne- of L16 （45） orthogonal experiment after studied the effect of solid to liquid ratio, extraction temperature, microwave treatment period, pH and microwave power on pectin extraction yield. Repetitive examinations of two methods were carried out separately, pectin extraction rate with the fLrst technique was 14.57% and that with the second method was 11.62%. The charac- teristics of the pectin sample prepared by alcohol deposition with acid hydrolysis were further investigated. The research demonstrated that mass percent of pectin was 87.23%. The esterification degree of pectin was 75.66% ,and pectin sample color was from creamy white to pale yellow.

Orange Peel Extract Mediated Silver Nanofluid as Corrosion Inhibitor for X80 Steel in Simulated Oilfield Scale Dissolver

Silver nanofluid was prepared by bio-reduction reaction between orange peels extracts(OPE)and silver nitrate and characterized by spectroscopic and microscopic techniques.Colloidal nanoparticles of sizes between 40-50 nm and spherical shape were obtained.The nanofluid was applied as anticorrosion additive to inhibit corrosion of X80 steel in simulated oilfield scale dissolver solution(1.0 M HCl)at various temperatures.The nanofluid(OPE-AgNPs)was 98.9% and 84.3% efficient at 30℃ and 60 ℃ respectively as determined by weight loss measurement.In comparison with OPE,OPE-AgNPs shows better corrosion inhibition and higher resistance to thermal degradation.Some kinetic and thermodynamic models were used to characterize the inhibition process.OPE-AgNPs could be optimized and used as alternative anticorrosion additive for scale dissolution liquor in the industry.

Pectinmethylesterase extraction from orange solid wastes: Optimization and comparison between conventional and ultrasound-assisted treatments

During orange juice production, a half of fresh oranges weight is considered as production waste (peels, pulp, seeds, orange leaves and damaged orange fruits). An alternative for the management of these wastes is their treatment by addition of lime and a latter pressing, obtaining a press cake and a press liquor rich in sugars (10°Brix) and citric acid, protein, pectin and ethanol. For non-thermal concentration of press liquor to obtain citruss molasses (65°-70°Brix), the removal of pectin is necessary. Traditionally, depectinization of juices has been done by using pectinmethylesterase (PME) enzymes from external sources. In this work it performed the extraction of PME enzymes from orange peels to obtain the optimum extraction conditions. Two different methods of solventextraction were compared (conventional andultrasound-assisted methods). For the conventional extraction experiments, a central composite design with three variables ([NaCl], pH and time) and five replicates of the center point was used. For ultrasound-assisted extraction, experiments were done at pH = 5.5 and [NaCl] = 1.25M), varying extraction time (1-30 min). Response variables were PME activity, protein content and a ratio between them, named PME effectiveness (ηPME). At the same experimental conditions (pH =5.5, [NaCl] = 1.25 M, t = 15 min) it was found that conventional extractions led to slightly better results in terms of ηPME than ultrasound-assisted extraction method.

Fast Determination of Essential Oil from Dried Menthol Mint and Orange Peel by Solvent Free Microwave Extraction Using Carbonyl Iron Powder as the Microwave Absorption Medium

An improved solvent free microwave extraction, in which a kind of microwave absorption medium （carbonyl iron powder） was used, was applied to the extraction of essential oil from dried menthol mint and orange peel without addition of any solvent and pretreatment. It took much less time of extraction （30 min） than microwave-assisted hydrodistillation （90 min） and conventional hydrodistillation （180 min）. The kinds of chemical compositions in essential oil extracted by different methods were almost the same and such improved solvent free microwave extraction can be a feasible way in extraction of essential oil from dried plant materials.

Eco-Friendly Production of Silver Nanoparticles from Peel of Tangerine for Degradation of Dye

Green chemistry methods for production of nanoparticles have many advantages, such as ease of use, which makes the methods desirable and economically viable. The aim of the present work was to green synthesise silver nanoparticles (SNPs) using aqueous tangerine peel extract in different ratios (2:1, 1:1, 1:2). The formed SNPs were characterised using ultraviolet-visible (UV-Vis) spectrophotometry, and transmission electron microscopy (TEM). The UV-Vis spectra showed that the highest absorbance was observed when the ratio of peel tangerine extract to silver nitrate solution was 1:2. The transmission electron micrographs showed the formation of poly dispersed nanoparticles. It was found that the average diameter of the nanoparticles was 30.29 ± 5.1 nm, 16.68 ± 5.7 nm, and 25.85 ± 8.4 nm, using a tangerine peel solution and silver nitrate solution ratio of 2:1, 1:1, and 1:2, respectively. The formed SNPs were evaluated as catalysts for methyl orange dye degradation, and the results confirmed that SNPs can speed up the degradation of the dye.

橙皮中柠檬烯提取工艺的研究进展

柠檬烯是橙皮中重要的化学成分,具有杀菌、抗氧化、抗病毒和降低胆固醇等生理活性作用,被广泛用于制药、食品和香料等领域。对溶剂萃取法、水蒸气蒸馏提取法、索氏提取法和超临界萃取法四种提取柠檬烯的方法进行介绍,引入其相关的检测方法和技术标准,旨为柠檬烯的应用生产提供参考价值。

生物酶辅助提取橘皮色素及其对羊绒染色的性能

为扩宽天然染料色谱并利用废弃物染色,通过生物酶辅助醇水提取橘皮中的天然色素,并将该色素应用于羊绒染色,分析该色素对羊绒染色的性能。首先分别用纤维素酶、果胶酶以及两种酶的组合对橘皮进行提取,通过单因素试验,探讨生物酶用量、乙醇浓度、提取温度、提取时间对提取效果的影响;然后采用橘皮色素对羊绒进行直接染色发现日晒牢度为2级,进一步研究提高日晒牢度的方法,实验结果表明用金属媒染剂、单宁-金属复合媒染剂、固色剂M对染色后羊绒进行后处理,以提高橘皮色素染色羊绒的耐日晒色牢度、耐皂洗色牢度。结果表明:橘皮色素最佳提取工艺为生物酶用量1%(o.w.f),其中纤维素酶和果胶酶质量比为2∶1,乙醇质量分数50%,提取温度80℃,提取时间100 min,料液比1∶20。橘皮色素对羊绒染色具有较高的K/S值,耐皂洗色牢度和耐日晒色牢度可达3级以上。从废弃物中提取天然染料色素,有着较高的应用价值和附加价值,为废弃资源再利用提供了一条有效途径。

桔皮中果胶提取技术的试验分析

酸浸提法提取果胶具有快速、简便、易于控制、提取率较高等特点 ,用盐酸浸提、乙醇沉淀法进行了从桔皮中提取果胶的工艺试验。研究结果表明 ,提取的液料质量比为 10～ 15、浸提液为 p H2～ 3、浸提时间为 4 5～6 0 m in、浸提温度为 80℃左右时 ,果胶提取效果较好。在单因素试验的基础上用正交试验进行工艺参数的优化 ,其适合的工艺条件是 :液料质量比为 10、浸提液 p H值为 2、浸提温度为 80℃、浸提时间为 4 5 min,在此工艺条件下进行试验 ,其果胶提取率达 70 .6 8%。

CO_2超临界流体萃取技术提取甜橙皮精油的研究

采用甜橙皮作为实验材料，研究在超临界状态下，粉碎度、温度、压力、静态萃取与动态萃取对油脂萃取率的影响，为批量生产提供了依据。

超声微波双辅助提取柑橘皮总黄酮的研究

为研究柑橘皮总黄酮的超声微波双辅助提取效果,对柑橘皮先进行超声再进行微波提取。应用单因素和正交试验,研究乙醇体积分数、固液比、微波功率及作用时间等因素对柑橘皮总黄酮提取率的影响。结果表明:采用超声微波双辅助提取技术得到的黄酮提取率较单独采用超声或微波辅助提取率高。以70%乙醇为溶剂、固液比1:20(g/mL)、40℃超声处理30min、微波功率400W、微波时间3min得到的总黄酮提取率为3.11%,结果较为理想。

柑橘皮果胶的改进提取工艺研究

以新鲜柑橘皮为原料,采用高速匀浆提取和对残渣进行酸水解再次提取的两步法提取工艺制备匀浆果胶和酸水解果胶产品。通过单因素试验和正交试验确定了匀浆提取和酸水解提取的最佳工艺参数并对果胶的脱色和分离方法进行了相关研究。实验结果表明,采用改进工艺提取后柑橘果胶产品总得率比普通一次性酸水解制备工艺明显提高;采用活性炭和聚酰胺为脱色剂进行果胶脱色可以有效提高脱色效果。

微波辅助提取橘皮果胶的优化条件研究

以橘皮为原料,用微波辅助法提取果胶,通过正交试验,得到优化工艺:以盐酸作为萃取剂,pH值为1.5,液料比为10:1(ml/g),微波加热时间为6min,微波处理方式为27%×800W。

柑桔皮总黄酮提取工艺的研究

主要研究乙醇浸提法提取柑桔皮总黄酮,考察溶剂浓度、提取温度、料液比、提取时间对柑桔皮总黄酮提取得率的影响,在单因素试验基础上通过正交试验优选出最佳提取工艺条件。结果表明,在φ=60%乙醇,提取温度为70℃、提取时间为3 h,料液比为1∶12的条件下提取效果最好,柑桔皮总黄酮提取得率为1.049%。

橙皮果胶的提取及性质研究

以脐橙皮为原料,经酸洗法处理后,以酸法提取橙皮果胶。通过单因素及正交实验确定果胶提取的最佳工艺为:料液比1∶25(m∶V),提取pH1.7,提取温度85℃,提取时间100min。最佳醇沉条件:果胶提取液与乙醇的体积比1∶2,提取pH3.5。提取的果胶,提取率为21.816%,半乳糖醛酸含量为70.66%,酯化度为72.49%。其他性质如水分(9.71%)、灰分(3.26%)和pH(2.93)等均满足国标要求,表明该方法适宜用于从橙皮中提取果胶。

陈皮等几种柑桔皮提取物对蚜、螨类害虫杀虫活性的初步研究

桔皮、橙皮和中药陈皮等几种提取物对胡萝卜微管蚜、豆蚜、红花指管蚜和桃蚜及截形叶螨、山楂叶螨进行室内生物测定。试验结果表明，这些提取物都具有较强活性。文中列出校正死亡率、毒力回归方程和ＬＣ＿（５０）（或ＬＤ＿（５０））。

从橙皮中提取香精油的工艺条件研究

以橙皮为试验材料 ,比较不同提取方法对香精油的质量和出油率的影响。研究表明 ,冷磨萃取法优于索氏提取法和浸提萃取法 ;以出油率为基准 ,冷磨萃取法适宜的工艺条件为 :搅拌时间为 2 0min ,石油醚溶剂与冷磨液体积比为 2∶5 ,萃取次数为 1次 ;精制后的香精油得率为 1 92 % ,其中含柠烯86 36 %。

超声波辅助提取甜橙果皮类胡萝卜素研究

为综合开发柑橘果皮,以甜橙果皮为原料,利用超声波技术提取类胡萝卜素。应用Box-Behnken正交试验设计,并采用高效液相色谱法分析其对类胡萝卜素组成的影响。结果表明:果皮干燥方式为冻干,粒径100～120目、料液比1:50(g/mL)、超声功率270W、超声时间7～10min、超声温度30～50℃、提取次数4～5次,经优化,类胡萝卜素含量范围为0.130～0.150mg/g,含量极值预测值为0.156mg/g,验证值为0.152mg/g。高效液相色谱分析表明在本实验条件下超声提取对类胡萝卜素主要成分没有明显影响。

水蒸汽蒸馏法提取橙皮精油的研究

针对影响水蒸汽蒸镏法提取橙皮精油的各重要因素,即提取时加入NaCl的浓度、提取时间、料液比(溶剂量),首先设计各因素单因素实验,然后设计正交实验进行了综合探究。结果表明:加入NaCl浓度4%,提取时间2.5h,料液比为1∶2(即加水量为橙皮量的2倍)的组合是最佳工艺组合。

响应面法优化超声波辅助提取橘皮中果胶类化合物

通过正交实验结合响应面法对超声波辅助酸解提取橘皮中果胶类化合物的提取工艺进行研究,探讨果胶类化合物提取的最佳工艺条件。结果表明:超声波辅助酸水解提取可以提高橘皮果胶类化合物的得率。提取液pH、超声波频率和提取温度对最终的果胶类化合物得率影响较大,其中提取液pH影响最为显著。响应面法优化后果胶的最佳提取工艺条件为:pH1·0、超声波频率20·7kHz、提取温度73℃,此时果胶类化合物得率可达18·2%。