Pub Date : 2021-07-13DOI: 10.2174/221333560801210603090602
Elisabete Clara Bastos Do Amaral Alegria
{"title":"Meet The Editorial Board Member","authors":"Elisabete Clara Bastos Do Amaral Alegria","doi":"10.2174/221333560801210603090602","DOIUrl":"https://doi.org/10.2174/221333560801210603090602","url":null,"abstract":"","PeriodicalId":43539,"journal":{"name":"Current Microwave Chemistry","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-07-13","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43372061","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-06-23DOI: 10.2174/2213335608666210623151121
Geetanjali, Ram Singh
Most of the traditional methods for organic synthesis have been associated with environmental concern. The transition from traditional to modern methods of synthesis is mainly based on principles of green chemistry to achieve better sustainability by reducing the negative impact on the environment and health. It has been found that microwaves as an energy source in organic synthesis have a great advantage over conventional heating. Microwave-assisted reactions are energy efficient and hence, brought themselves in the preview green chemistry principles. The use of safer solvents is another important principle of green chemistry. The use of water as a solvent in organic synthesis has great benefits over the use of hazardous organic solvents in terms of environment and safety. This study will cover the use of both microwave and water simultaneously in organic reactions.
{"title":"Microwave-assisted organic synthesis in Water","authors":"Geetanjali, Ram Singh","doi":"10.2174/2213335608666210623151121","DOIUrl":"https://doi.org/10.2174/2213335608666210623151121","url":null,"abstract":"\u0000\u0000Most of the traditional methods for organic synthesis have been associated with environmental concern. The transition from traditional to modern methods of synthesis is mainly based on principles of green chemistry to achieve better sustainability by reducing the negative impact on the environment and health. It has been found that microwaves as an energy source in organic synthesis have a great advantage over conventional heating. Microwave-assisted reactions are energy efficient and hence, brought themselves in the preview green chemistry principles. The use of safer solvents is another important principle of green chemistry. The use of water as a solvent in organic synthesis has great benefits over the use of hazardous organic solvents in terms of environment and safety. This study will cover the use of both microwave and water simultaneously in organic reactions.\u0000","PeriodicalId":43539,"journal":{"name":"Current Microwave Chemistry","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-06-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45294305","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-04-01DOI: 10.2174/2213335608666210401152153
Monika R. Tiwari, N. Patel
The study aims to synthesize thiocoumarin scaffolds clubbed with pyrimidine and 1,3,4-oxadiazole ring system under microwave irradiation and describe their pharmacological activities. We report herein an efficient and simple Lewis acid-catalyzed procedure for the synthesis of novel series of thiocoumarin clubbed with pyrimidine and 1,3,4-oxadiazole motifs under microwave irradiation. The microwave-assisted technique has many advantages, such as a higher yield, a clean and selective procedure, shorter reaction time, and simple work-up. The objective of the present study is to design and synthesize thiocoumarin scaffolds clubbed with pyrimidine and 1,3,4-oxadiazole ring system by microwave-assisted heating. Our prime focus is to highlight the synthetic approach developed for the synthesis of heterocyclic moieties of pharmacological interest, and the prominence has also been given to distinct advantages provided by microwave heating. Thiocoumarin clubbed with pyrimidine, and 1,3,4-oxadiazole motifs was synthesized under microwave irradiation. All the synthesized molecules were evicted by IR, 1H NMR, 13C NMR, and mass spectra. The anti-microbial activity of synthesized compounds was examined against two Gram-negative bacteria (E. coli, P. aeruginosa), two Gram-positive bacteria (S. aureus, S. pyogenes), and three fungi (C. albicans, A. niger, A. clavatus) using the MIC (Minimal Inhibitory Concentration) method, anti-tubercular activity H37Rv using L. J. Slope Method and anti- oxidant activity using DPPH and ABTS bioassay method. The application of microwave technology for the rapid synthesis of biologically significant thiocoumarin analogues is very promising because of its shorter reaction time and higher yield. Some of these new derivatives showed moderate to good in-vitro anti-bacterial, anti-fungal, and anti-tubercular activity. Compounds B4 and B7 appeared to have high radical scavenging efficacies as 35.32 ± 0.446 and 33.97 ± 1.069 μg/mL ± SD of IC50 values in DPPH and ABTS bioassay, respectively. Microwave-assisted synthesis provides an implicit way to discover a promising class of molecular entities for the development of new anti-microbial and anti-oxidant agents. Oxadiazole and pyrimidine bearing thiocoumarin derivatives showed improved anti-microbial, antitubercular, and anti-oxidant activity.
本研究目的是在微波照射下合成嘧啶- 1,3,4-恶二唑环系硫代香豆素支架，并描述其药理活性。本文报道了一种在微波辐射下高效、简单的Lewis酸催化合成嘧啶和1,3,4-恶二唑基序的新型硫代香豆素系列化合物。微波辅助技术具有收率高、工艺干净、选择性好、反应时间短、后处理简单等优点。本研究的目的是设计和合成巯基香豆素-嘧啶- 1,3,4-恶二唑环体系的微波辅助加热支架。我们的主要重点是强调为合成具有药理意义的杂环基团而开发的合成方法，并且也突出了微波加热提供的独特优势。在微波辐射下合成了巯基香豆素与嘧啶和1,3,4-恶二唑基序。所有合成的分子通过IR、1H NMR、13CNMR和质谱进行了分离。测定了合成的化合物对2种革兰氏阴性菌(大肠杆菌、铜绿假单胞菌)、2种革兰氏阳性菌(金黄色葡萄球菌、金黄色葡萄球菌)的抑菌活性。MIC (minimum inhibityconcentration)法测定3种真菌(C. albicans, A. niger, A. clavatus)， L. J. Slope法测定抗结核活性H37Rv, DPPH和ABTS生物测定法测定抗氧化活性。微波技术具有反应时间短、产率高的优点，在快速合成具有重要生物学意义的硫代香豆素类似物方面具有广阔的应用前景。这些新的衍生物显示出中等到良好的体外抗菌、抗真菌和抗结核活性。化合物B4和B7具有较强的自由基清除能力，DPPH和ABTS的IC50值分别为35.32±0.446和33.97±1.069 μg/mL±SD。微波辅助合成为开发新的抗微生物和抗氧化剂提供了一种潜在的方法来发现一类有前途的分子实体。含恶二唑和嘧啶的硫代香豆素衍生物具有较好的抗微生物、抗结核和抗氧化活性。
{"title":"Synthesis and Pharmacological Activities of Oxadiazole and Pyrimidine Bearing Thiocoumarin Derivatives","authors":"Monika R. Tiwari, N. Patel","doi":"10.2174/2213335608666210401152153","DOIUrl":"https://doi.org/10.2174/2213335608666210401152153","url":null,"abstract":"\u0000\u0000The study aims to synthesize thiocoumarin scaffolds clubbed with pyrimidine\u0000and 1,3,4-oxadiazole ring system under microwave irradiation and describe their pharmacological\u0000activities.\u0000\u0000\u0000\u0000We report herein an efficient and simple Lewis acid-catalyzed procedure for the\u0000synthesis of novel series of thiocoumarin clubbed with pyrimidine and 1,3,4-oxadiazole motifs\u0000under microwave irradiation. The microwave-assisted technique has many advantages, such as a\u0000higher yield, a clean and selective procedure, shorter reaction time, and simple work-up.\u0000\u0000\u0000\u0000The objective of the present study is to design and synthesize thiocoumarin scaffolds\u0000clubbed with pyrimidine and 1,3,4-oxadiazole ring system by microwave-assisted heating. Our\u0000prime focus is to highlight the synthetic approach developed for the synthesis of heterocyclic moieties\u0000of pharmacological interest, and the prominence has also been given to distinct advantages\u0000provided by microwave heating.\u0000\u0000\u0000\u0000 Thiocoumarin clubbed with pyrimidine, and 1,3,4-oxadiazole motifs was synthesized\u0000under microwave irradiation. All the synthesized molecules were evicted by IR, 1H NMR, 13C\u0000NMR, and mass spectra. The anti-microbial activity of synthesized compounds was examined\u0000against two Gram-negative bacteria (E. coli, P. aeruginosa), two Gram-positive bacteria (S. aureus,\u0000S. pyogenes), and three fungi (C. albicans, A. niger, A. clavatus) using the MIC (Minimal Inhibitory\u0000Concentration) method, anti-tubercular activity H37Rv using L. J. Slope Method and anti-\u0000oxidant activity using DPPH and ABTS bioassay method.\u0000\u0000\u0000\u0000The application of microwave technology for the rapid synthesis of biologically significant\u0000thiocoumarin analogues is very promising because of its shorter reaction time and higher\u0000yield. Some of these new derivatives showed moderate to good in-vitro anti-bacterial, anti-fungal,\u0000and anti-tubercular activity. Compounds B4 and B7 appeared to have high radical scavenging efficacies\u0000as 35.32 ± 0.446 and 33.97 ± 1.069 μg/mL ± SD of IC50 values in DPPH and ABTS bioassay,\u0000respectively.\u0000\u0000\u0000\u0000Microwave-assisted synthesis provides an implicit way to discover a promising class\u0000of molecular entities for the development of new anti-microbial and anti-oxidant agents. Oxadiazole\u0000and pyrimidine bearing thiocoumarin derivatives showed improved anti-microbial, antitubercular,\u0000and anti-oxidant activity.\u0000","PeriodicalId":43539,"journal":{"name":"Current Microwave Chemistry","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-04-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42220908","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-12DOI: 10.2174/2213335608666210212103541
T. S. Ntelane, Themba E. Tshabalala, C. M. Masuku, M. Scurrell
To use the microwave radiation as the post-treatment method to tune the acidic properties of Fe/ZSM-5 catalyst. ZSM-5 zeolite is a widely used standard catalyst in the methanol conversion to olefins and high-octane gasoline range hydrocarbons. However, the coke deposition and the concentration of acid sites determine its overall catalytic activity. Thus, the concentration of acid sites more precisely, the number of Brønsted acid sites, is vital in determining the activity of ZSM-5 zeolite and product distribution in the methanol-to-hydrocarbons reaction. (1) To modify ZSM-5 using an iron solution to form Fe/ZSM-5 via the impregnation method. (2) To tune the acidic properties of Fe/ZSM-5 using microwave radiation. (3) To check and determine the concentration of acidic sites using n-propylamine temperature-programmed surface reaction. (4) To check the effect of microwave radiation and acidic properties in the methanol conversion (product distribution) via methanol temperature-programmed surface reaction. Two sets of zeolites were used, with iron being introduced by ion-exchange from ferric nitrate (Fe(NO3)3 9H2O, Sigma Aldrich, ≥ 98% metal) solutions. These two series were designated as Z (0.5FeZ10/0-700) and X (0.5FeX10/0-700) after microwave treatment. The Z and X series possess the Si/Al framework ratio of 30 and 80, respectively. The TPSR studies were then conducted for characterization and catalytic tests. From the C3H9N-TPSR experiments, it was found that the concentration of Brønsted acid sites decreased with increasing microwave power level. Both X and Z series exhibited high selectivity to propene than ethene. Microwave treated catalysts (0.5FeZ10/280 and 0.5FeX10/462) with decreased concentration of Brønsted acid sites showed the highest propene/ethene ratios of 1.67 and 5.27, respectively. From the results obtained, it was found that the amount of methane evolved (as a measure of coke deposited) and the concentration of Brønsted acid sites decreased with increasing microwave power level (0-700 Watts). High selectivity to propene was found when using both X series (0.5FeX10/0-700) and Z series (0.5FeZ10/0-700) as catalysts. After decreasing the concentration of Brønsted acid using microwave treatment, the highest P/E ratios were observed for 0.5FeX10/280, 0.5FeX10/462, 0.5FeZ10/280 and 0.5FeZ10/462 catalysts. It is reasonable to suggest that microwave radiation could be a feasible post-synthesis modification step to produce ZSM-5 based catalysts that exhibit reduced concentration of Brønsted acid sites, reduced methane formation, increased catalytic activity and selectivity.
{"title":"Microwave Radiation Effects on the Acidic Properties of Fe/ZSM-5 Catalysts for Methanol Conversion","authors":"T. S. Ntelane, Themba E. Tshabalala, C. M. Masuku, M. Scurrell","doi":"10.2174/2213335608666210212103541","DOIUrl":"https://doi.org/10.2174/2213335608666210212103541","url":null,"abstract":"\u0000\u0000To use the microwave radiation as the post-treatment method to tune the acidic\u0000properties of Fe/ZSM-5 catalyst.\u0000\u0000\u0000\u0000ZSM-5 zeolite is a widely used standard catalyst in the methanol conversion to\u0000olefins and high-octane gasoline range hydrocarbons. However, the coke deposition and the concentration\u0000of acid sites determine its overall catalytic activity. Thus, the concentration of acid sites\u0000more precisely, the number of Brønsted acid sites, is vital in determining the activity of ZSM-5 zeolite\u0000and product distribution in the methanol-to-hydrocarbons reaction.\u0000\u0000\u0000\u0000(1) To modify ZSM-5 using an iron solution to form Fe/ZSM-5 via the impregnation\u0000method.\u0000\u0000(2) To tune the acidic properties of Fe/ZSM-5 using microwave radiation.\u0000\u0000(3) To check and determine the concentration of acidic sites using n-propylamine temperature-programmed\u0000surface reaction.\u0000\u0000(4) To check the effect of microwave radiation and acidic properties in the methanol conversion\u0000(product distribution) via methanol temperature-programmed surface reaction.\u0000\u0000\u0000\u0000Two sets of zeolites were used, with iron being introduced by ion-exchange from ferric\u0000nitrate (Fe(NO3)3 9H2O, Sigma Aldrich, ≥ 98% metal) solutions. These two series were designated\u0000as Z (0.5FeZ10/0-700) and X (0.5FeX10/0-700) after microwave treatment. The Z and X series possess the\u0000Si/Al framework ratio of 30 and 80, respectively. The TPSR studies were then conducted for characterization\u0000and catalytic tests.\u0000\u0000\u0000\u0000From the C3H9N-TPSR experiments, it was found that the concentration of Brønsted acid\u0000sites decreased with increasing microwave power level. Both X and Z series exhibited high selectivity\u0000to propene than ethene. Microwave treated catalysts (0.5FeZ10/280 and 0.5FeX10/462) with decreased\u0000concentration of Brønsted acid sites showed the highest propene/ethene ratios of 1.67 and\u00005.27, respectively.\u0000\u0000\u0000\u0000From the results obtained, it was found that the amount of methane evolved (as a measure\u0000of coke deposited) and the concentration of Brønsted acid sites decreased with increasing microwave\u0000power level (0-700 Watts). High selectivity to propene was found when using both X series\u0000(0.5FeX10/0-700) and Z series (0.5FeZ10/0-700) as catalysts. After decreasing the concentration of\u0000Brønsted acid using microwave treatment, the highest P/E ratios were observed for 0.5FeX10/280,\u00000.5FeX10/462, 0.5FeZ10/280 and 0.5FeZ10/462 catalysts.\u0000\u0000\u0000\u0000It is reasonable to suggest that microwave radiation could be a feasible post-synthesis modification\u0000step to produce ZSM-5 based catalysts that exhibit reduced concentration of Brønsted acid sites, reduced\u0000methane formation, increased catalytic activity and selectivity.\u0000","PeriodicalId":43539,"journal":{"name":"Current Microwave Chemistry","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-02-12","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47198010","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-02-01DOI: 10.2174/2213335608666210329130736
Bishwajit Changmai, K. Rajkumari, D. Das, Lalthazuala Rokhum
Synthesis and application of acid-functionalized mesoporous polymer catalyst for the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones via Biginelli condensation reaction under microwave irradiation is investigated. Several analytical techniques such as FT-IR, BET, TEM, SEM and EDX were employed to characterize the synthesized polymeric catalyst. High acidity (1.15 mmol g-1 ), high surface area (90.44 m2 g -1 ) and mesoporous nature of the catalyst effectively promoted the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones. Microwave irradiation shows higher yield (89-98 %) as compared to conventional heating (15-25 % yield) under our optimized reaction conditions such as 1:1:1.2 molar ratio of aldehyde/ethylacetoacetate/urea, catalyst loading of 6 wt.% (with respect to aldehyde), the temperature of 80 °C and microwave power of 50 W. The synthesized Biginelli products were fully characterized by 1H and 13C NMR. The reusability of the catalyst was investigated up to 5 successive cycles and it showed great stability towards the synthesis of 3,4-Dihydropyrimidin-2(1H)-ones without any significant depreciation in yields.
{"title":"Microwave-Assisted Synthesis of 3,4-Dihydropyrimidin-2(1H)-Ones Using Acid-Functionalized Mesoporous Polymer","authors":"Bishwajit Changmai, K. Rajkumari, D. Das, Lalthazuala Rokhum","doi":"10.2174/2213335608666210329130736","DOIUrl":"https://doi.org/10.2174/2213335608666210329130736","url":null,"abstract":"Synthesis and application of acid-functionalized mesoporous polymer catalyst for the synthesis of\u00003,4-Dihydropyrimidin-2(1H)-ones via Biginelli condensation reaction under microwave\u0000irradiation is investigated. Several analytical techniques such as FT-IR, BET, TEM, SEM and EDX\u0000were employed to characterize the synthesized polymeric catalyst. High acidity (1.15 mmol g-1\u0000),\u0000high surface area (90.44 m2\u0000g\u0000-1\u0000) and mesoporous nature of the catalyst effectively promoted the\u0000synthesis of 3,4-Dihydropyrimidin-2(1H)-ones. Microwave irradiation shows higher yield (89-98\u0000%) as compared to conventional heating (15-25 % yield) under our optimized reaction conditions\u0000such as 1:1:1.2 molar ratio of aldehyde/ethylacetoacetate/urea, catalyst loading of 6 wt.% (with\u0000respect to aldehyde), the temperature of 80 °C and microwave power of 50 W. The synthesized\u0000Biginelli products were fully characterized by 1H and 13C NMR. The reusability of the catalyst\u0000was investigated up to 5 successive cycles and it showed great stability towards the synthesis of\u00003,4-Dihydropyrimidin-2(1H)-ones without any significant depreciation in yields.","PeriodicalId":43539,"journal":{"name":"Current Microwave Chemistry","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-02-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"45219211","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2021-01-06DOI: 10.2174/2213335607666210106094449
Fumiyoshi Ozaki, Y. Okada
Microwave-assisted Claisen rearrangement of allyloxybenzene with a hydroxyl group was conducted in the presence of metal salts. The rearrangement was promoted in the presence of an alkali metal salt, because the reaction substrate was converted into a phenoxide-type ion, which can efficiently absorb microwaves. In contrast, a Lewis acid was strongly coordinated to the ethereal oxygen, and this structure could also absorb microwaves efficiently.
{"title":"Microwave-assisted Claisen Rearrangement of 1-Allyloxy-4-hydroxybenzene in the Presence of Metal Salt","authors":"Fumiyoshi Ozaki, Y. Okada","doi":"10.2174/2213335607666210106094449","DOIUrl":"https://doi.org/10.2174/2213335607666210106094449","url":null,"abstract":"\u0000\u0000Microwave-assisted Claisen rearrangement of allyloxybenzene with a hydroxyl group\u0000was conducted in the presence of metal salts. The rearrangement was promoted in the presence of\u0000an alkali metal salt, because the reaction substrate was converted into a phenoxide-type ion, which\u0000can efficiently absorb microwaves. In contrast, a Lewis acid was strongly coordinated to the ethereal\u0000oxygen, and this structure could also absorb microwaves efficiently.\u0000","PeriodicalId":43539,"journal":{"name":"Current Microwave Chemistry","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2021-01-06","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48616658","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-31DOI: 10.2174/2213335607999201231212208
G. Yildiz
The objective of this study was to investigate the impacts of combined microwave- convective drying on the quality of dried-pears. Color, bioactive compounds (total phenolics (TP) and antioxidant capacity (AC)) and textural (hardness) properties of convective (50 and 60 °C), microwave (100 and 200 W), and combined microwave-convective (100-50 °C, 200W-50 °C, 100 W-60 °C and 200 W-60 °C) dried pears were compared with the untreated pears. A Konica Minolta CR-400 Chroma Meter was used to examine the color changes in dried pears. TP was measured using the Folin-Ciocalteu reagent. The free radical scavenging activity of the extract was analyzed using 1,1-dipheyl-2-picylhydrazyl (DPPH). The hardness of dried pear slices with different drying methods was obtained by a texture analyzer. The microwave- convective dried pear slices (especially at the condition of 200 W - 60 °C) showed higher preservation of bioactive compounds in addition to improved textural properties and color compared to other dried pear samples. Overall, combined microwave-convective drying is a promising process, as demonstrated in current research by its capability to better retain dried pear quality in terms of functional and textural properties.
研究了微波-对流联合干燥对梨干品质的影响。对对流干燥(50和60℃)、微波干燥(100和200W)以及微波-对流复合干燥(100-50℃、200W-50℃、100 W-60℃和200W- 60℃)的梨与未经处理的梨进行了颜色、生物活性物质(总酚类物质(TP)和抗氧化能力(AC))和质地(硬度)性能的比较。采用柯尼卡美能达CR-400色度仪检测干梨的颜色变化。TP采用Folin-Ciocalteu试剂测定。采用1,1-二苯基-2-酰基肼(DPPH)法测定其自由基清除活性。用质构分析仪测定了不同干燥方法干燥后梨片的硬度。微波对流干燥的梨片(特别是在200 W - 60°C的条件下)与其他干燥的梨样品相比，具有更高的生物活性成分保存，并且改善了梨的质地和颜色。总的来说，微波-对流联合干燥是一种很有前途的方法，目前的研究表明，微波-对流联合干燥能够更好地保持干燥梨的功能和质地特性。
{"title":"The Effect of Novel Microwave-Convective Drying on the Functional Properties of Dried-Pears (Pyrus communis)","authors":"G. Yildiz","doi":"10.2174/2213335607999201231212208","DOIUrl":"https://doi.org/10.2174/2213335607999201231212208","url":null,"abstract":"\u0000\u0000The objective of this study was to investigate the impacts of combined microwave-\u0000convective drying on the quality of dried-pears. Color, bioactive compounds (total\u0000phenolics (TP) and antioxidant capacity (AC)) and textural (hardness) properties of convective (50\u0000and 60 °C), microwave (100 and 200 W), and combined microwave-convective (100-50 °C,\u0000200W-50 °C, 100 W-60 °C and 200 W-60 °C) dried pears were compared with the untreated pears.\u0000\u0000\u0000\u0000A Konica Minolta CR-400 Chroma Meter was used to examine the color\u0000changes in dried pears. TP was measured using the Folin-Ciocalteu reagent. The free radical scavenging\u0000activity of the extract was analyzed using 1,1-dipheyl-2-picylhydrazyl (DPPH). The hardness\u0000of dried pear slices with different drying methods was obtained by a texture analyzer. The microwave-\u0000convective dried pear slices (especially at the condition of 200 W - 60 °C) showed higher\u0000preservation of bioactive compounds in addition to improved textural properties and color compared\u0000to other dried pear samples.\u0000\u0000\u0000\u0000Overall, combined microwave-convective drying is a promising process, as demonstrated\u0000in current research by its capability to better retain dried pear quality in terms of functional\u0000and textural properties.\u0000","PeriodicalId":43539,"journal":{"name":"Current Microwave Chemistry","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"46251736","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-31DOI: 10.2174/2213335607999201231212005
Yeqing Ling, Qiannan Li, Hewen Zheng, M. Omran, Zhi Yang
As a new technology for preparing zirconia materials, microwave-assisted technology has been widely concerned in recent years. In this paper, the microwave-assisted method and its application in the preparation of inorganic materials are briefly described. The research progress of the preparation of zirconia by microwave-assisted method is reviewed. Some problems existing in the research status are pointed out, and the application prospect in this field is prospected.
{"title":"A Review of Microwave Synthesis of Zirconia Composite Ceramics","authors":"Yeqing Ling, Qiannan Li, Hewen Zheng, M. Omran, Zhi Yang","doi":"10.2174/2213335607999201231212005","DOIUrl":"https://doi.org/10.2174/2213335607999201231212005","url":null,"abstract":"\u0000\u0000As a new technology for preparing zirconia materials, microwave-assisted technology\u0000has been widely concerned in recent years. In this paper, the microwave-assisted method and its application\u0000in the preparation of inorganic materials are briefly described. The research progress of\u0000the preparation of zirconia by microwave-assisted method is reviewed. Some problems existing in\u0000the research status are pointed out, and the application prospect in this field is prospected.\u0000","PeriodicalId":43539,"journal":{"name":"Current Microwave Chemistry","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-12-31","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"43489758","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2020-12-22DOI: 10.2174/2213335607999201222095248
Li Qiannan, Li Yeqing, Zheng Hewen, Yang Zhi
Manganese ore is an important metallurgical raw material that holds an important strategic position in the national economy of China. However, the grade of manganese ore in the country is mostly low, and the utilization efficiency of low-grade manganese ore resources is low, which seriously restricts the healthy and stable development of China’s metallurgical industry. As a new green heating method, microwave is expected to address the problems of conventional methods and realize the effective utilization of low-grade manganese ore. In this paper, the research status of the microwave composite reduction of pyrolusite in recent years is reviewed. Microwave plays an important role in metallurgy, and it is the current direction pursued to improve the research level of microwave heating and extend it to actual industrial processes.
{"title":"Research Status of Microwave-assisted Reduction Technology of Pyrolusite","authors":"Li Qiannan, Li Yeqing, Zheng Hewen, Yang Zhi","doi":"10.2174/2213335607999201222095248","DOIUrl":"https://doi.org/10.2174/2213335607999201222095248","url":null,"abstract":"\u0000\u0000Manganese ore is an important metallurgical raw material that holds an important strategic\u0000position in the national economy of China. However, the grade of manganese ore in the country\u0000is mostly low, and the utilization efficiency of low-grade manganese ore resources is low, which seriously\u0000restricts the healthy and stable development of China’s metallurgical industry. As a new\u0000green heating method, microwave is expected to address the problems of conventional methods\u0000and realize the effective utilization of low-grade manganese ore. In this paper, the research status\u0000of the microwave composite reduction of pyrolusite in recent years is reviewed. Microwave plays\u0000an important role in metallurgy, and it is the current direction pursued to improve the research level\u0000of microwave heating and extend it to actual industrial processes.\u0000","PeriodicalId":43539,"journal":{"name":"Current Microwave Chemistry","volume":" ","pages":""},"PeriodicalIF":0.8,"publicationDate":"2020-12-22","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"42584090","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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