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Jia L, Shao L, Zhao Y, Sun Y, Li X, Dai R. Inactivation effects and mechanism of ohmic heating on Bacillus cereus. Int J Food Microbiol 2023; 390:110125. [PMID: 36774686 DOI: 10.1016/j.ijfoodmicro.2023.110125] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/02/2022] [Revised: 12/28/2022] [Accepted: 02/06/2023] [Indexed: 02/12/2023]
Abstract
The inactivation effects and mechanism of ohmic heating (OH) on Bacillus cereus ATCC 11778 were investigated in this study, conventional heating (CH) was also carried out and served as control. All OH treatments (10 V/cm 50 Hz, 10 V/cm 500 Hz, 5 V/cm 50 Hz and 5 V/cm 500 Hz) could achieve a comparable inactivation effect with CH, while OH treatments significantly shortened the processing time. OH treated cells exhibited significantly higher leakage of metal ions (Mg2+ and K+) and biomacromolecules (nucleic acids and proteins) than those treated with CH when bacterial suspensions were heated to the same temperature. Moreover, OH treatment caused more damage on membrane structure, greatly decreased the cell membrane potential and endogenous enzyme activity than that of CH. The results of this study indicated that OH is more efficient in the inactivation of bacteria.
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Affiliation(s)
- Lihong Jia
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Lele Shao
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Yijie Zhao
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Yingying Sun
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Xingmin Li
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China
| | - Ruitong Dai
- Beijing Higher Institution Engineering Research Center of Animal Product, College of Food Science and Nutritional Engineering, China Agricultural University, No. 17 Qinghua East Road, Haidian District, Beijing 100083, PR China.
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2
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Dávila I, Gullón P, Labidi J. Influence of the heating mechanism during the aqueous processing of vine shoots for the obtaining of hemicellulosic oligosaccharides. Waste Manag 2021; 120:146-155. [PMID: 33302017 DOI: 10.1016/j.wasman.2020.11.014] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/01/2020] [Revised: 11/16/2020] [Accepted: 11/17/2020] [Indexed: 06/12/2023]
Abstract
This work deals with the revalorization of an important winery residue such as the vine shoots by the obtaining of oligosaccharides with potential prebiotic activity. The manufacture of these added-value products was performed by an autohydrolysis treatment assisted with microwaves to make the process less time consuming and more environmentally friendly. The influence of the reaction time (0-40 min) and the temperature (140-200) on the production of oligosaccharides during the microwave-assisted autohydrolysis was evaluated. The highest concentration of oligosaccharides (168.3 g/Kg oven-dried vines shoots) was achieved during the treatment carried out at 180 °C for 20 min. To assess the benefits of the assistance of the autohydrolysis treatment with the microwaves a conventionally heated treatment was performed using conditions (180 °C for 15 min) that provoked similar effects on the solubilisation of the hemicellulosic fraction. This treatment permitted the obtaining of 203.5 g oligosaccharides/Kg oven-dried vines shoots using 61.0% more of the time needed to carry out the microwaves-assisted autohydrolysis. Although the microwave-assisted treatment permitted the manufacture of a lower amount of oligosaccharides, only consumed 28.8% of the energy needed to perform the conventionally heated treatment. The oligosaccharides manufactured by the two treatments were substituted xyloglucans with different polymerization and acetylation degrees, which due to their potential prebiotic activity could be highly appreciated by pharmaceuticals and food industries. Thus, this work demonstrated the environmental sustainability of the microwave-assisted autohydrolysis for the revalorisation of the vine shoots.
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Affiliation(s)
- Izaskun Dávila
- Department of Chemical and Environmental Engineering, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
| | - Patricia Gullón
- Department of Chemical and Environmental Engineering, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain
| | - Jalel Labidi
- Department of Chemical and Environmental Engineering, University of the Basque Country, UPV/EHU, 20018 San Sebastián, Spain.
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3
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Mapengo CR, Emmambux MN. Functional properties of heat-moisture treated maize meal with added stearic acid by infrared energy. Food Chem 2020; 325:126846. [PMID: 32387987 DOI: 10.1016/j.foodchem.2020.126846] [Citation(s) in RCA: 10] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Revised: 04/06/2020] [Accepted: 04/16/2020] [Indexed: 11/30/2022]
Abstract
Functional properties of infrared heat-moisture treated (HMT) maize meal with stearic acid were studied. Maize meal with 1.5% stearic acid (SA) was treated by HMT using infrared (IR) energy (at 110 °C for 1, 2 & 3 h) and conventional HMT (at 110 °C for 16 h) independently. Infrared HMT is similar to conventional HMT since both treatments resulted in significantly (P < 0.05) reduced final viscosity and reduced in vitro starch digestibility in maize meal with stearic acid. These changes related correspond with the presence of V-type polymorphs (Type II) and increased in relative crystallinity showed by differential scanning calorimetry and X-ray diffraction scattering, respectively. These results suggested that infrared HMT changes the functional and nutritional properties of maize meal with SA and has the potential to replace conventional HMT in the development of lower GI, higher value-added functional starch foodstuffs.
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Affiliation(s)
- Clarity R Mapengo
- Department of Consumer and Food Sciences, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa
| | - M Naushad Emmambux
- Department of Consumer and Food Sciences, University of Pretoria, Private Bag X20, Hatfield, Pretoria 0028, South Africa.
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Darvishi H, Koushesh Saba M, Behroozi-Khazaei N, Nourbakhsh H. Improving quality and quantity attributes of grape juice concentrate (molasses) using ohmic heating. J Food Sci Technol 2020; 57:1362-1370. [PMID: 32180632 PMCID: PMC7054542 DOI: 10.1007/s13197-019-04170-1] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Revised: 10/25/2019] [Accepted: 11/08/2019] [Indexed: 10/25/2022]
Abstract
The effect of ohmic heating method (OHM) on quality and quantity attributes of black grape molasses was investigated and compared with the conventional heating method (CHM). Results showed that the samples prepared by OHM had the highest antioxidant activity than CHM. Increasing of voltage gradient had a positive effect on the saving of antioxidant activity. Changes in pH for OHM were lower than CHM. Heating methods had no significant effect on phenol content. Antioxidant capacity and phenol content of treated samples were lower than the fresh sample at the same water content. The titratable acidity of treated samples using CHM was higher than the OHM. The OHM saved about 2.4-7.2-fold of processing time and 6.3-fold of energy consumption than the CHM. Heat generation and electrical conductivity depended on sample moisture content. OHM provides minimal damage to the sensory characteristics. As a final result, the OHM significantly improved the quality and saved the quantity parameters of the grape molasses processing than the CHM.
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Affiliation(s)
- Hosain Darvishi
- Department of Biosystems Engineering, Faculty of Agriculture, University of Kurdistan, P.O. Box: 416, Sanandaj, Kurdistan Iran
| | - Mahmoud Koushesh Saba
- Department of Horticultural Science, Faculty of Agriculture, University of Kurdistan, Sanandaj, Kurdistan Iran
| | - Nasser Behroozi-Khazaei
- Department of Biosystems Engineering, Faculty of Agriculture, University of Kurdistan, P.O. Box: 416, Sanandaj, Kurdistan Iran
| | - Himan Nourbakhsh
- Department of Food Science and Engineering, Faculty of Agriculture, University of Kurdistan, Sanandaj, Kurdistan Iran
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Tinoco A, Rodrigues RM, Machado R, Pereira RN, Cavaco-Paulo A, Ribeiro A. Ohmic heating as an innovative approach for the production of keratin films. Int J Biol Macromol 2020; 150:671-80. [PMID: 32061691 DOI: 10.1016/j.ijbiomac.2020.02.122] [Citation(s) in RCA: 15] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [What about the content of this article? (0)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2019] [Revised: 01/31/2020] [Accepted: 02/12/2020] [Indexed: 12/17/2022]
Abstract
Ohmic heating is a thermal processing method based on the application of electric fields directly into a semi-conductive medium. In this study, we explored for the first time the use of ohmic heating to obtain keratin films. The properties of the films prepared by ohmic heating and conventional heating were evaluated and compared under similar thermal profiles. A lower increase in free thiols' concentration was obtained for the keratin solutions and keratin films submitted to ohmic heating (16% increase for the keratin solution extracted from virgin hair, pH 9, submitted to ohmic heating and 23% when submitted to conventional heating). Significant differences in the swelling results were observed for the films prepared with keratin extracted from virgin hair, with a swelling decrease in about 55% for the films prepared by ohmic heating. Generally, the keratin films obtained by ohmic heating showed distinct properties comparatively to the films produced by conventional methods. The application of a fusion protein on the keratin films demonstrated their capacity to be used as substitutes to hair fibers when evaluating the potential of new cosmetic products. This work suggests that ohmic heating show potential to tailor keratin films properties depending on an intended application or functionality.
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Kaczmarska K, Grabowska B, Bobrowski A, Cukrowicz S. Effects of curing conditions on the structure of sodium carboxymethyl starch/mineral matrix system: FT-IR investigation. Spectrochim Acta A Mol Biomol Spectrosc 2018; 201:236-241. [PMID: 29753969 DOI: 10.1016/j.saa.2018.04.049] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/31/2017] [Revised: 04/20/2018] [Accepted: 04/23/2018] [Indexed: 06/08/2023]
Abstract
Strength properties of the microwave cured molding sands containing binders in a form of the aqueous solution of sodium carboxymethyl starch (CMS-Na) are higher than the same molding composition cured by conventional heating. Finding the reason of this effect was the main purpose in this study. Structural changes caused by both physical curing methods of molding sands systems containing mineral matrix (silica sand) and polymer water-soluble binder (CMS-Na) were compared. It was shown, by means of the FT-IR spectroscopic studies, that the activation of the polar groups in the polymer macromolecules structure as well as silanol groups on the mineral matrix surfaces was occurred in the microwave radiation. Binding process in microwave-cured samples was an effect of formation the hydrogen bonds network between hydroxyl and/or carbonyl groups present in polymer and silanol groups present in mineral matrix. FT-IR studies of structural changes in conventional and microwave cured samples confirm that participation of hydrogen bonds is greater after microwave curing than conventional heating.
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Affiliation(s)
- Karolina Kaczmarska
- AGH - University of Science and Technology, Faculty of Foundry Engineering, Reymonta 23, 30 059 Krakow, Poland.
| | - Beata Grabowska
- AGH - University of Science and Technology, Faculty of Foundry Engineering, Reymonta 23, 30 059 Krakow, Poland
| | - Artur Bobrowski
- AGH - University of Science and Technology, Faculty of Foundry Engineering, Reymonta 23, 30 059 Krakow, Poland
| | - Sylwia Cukrowicz
- AGH - University of Science and Technology, Faculty of Foundry Engineering, Reymonta 23, 30 059 Krakow, Poland
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Oueslati I, Manaï H, Madrigal-Martínez M, Martínez-Cañas MA, Sánchez-Casas J, Zarrouk M, Flamini G. Volatile molecular markers of VOO Thermo-oxidation: Effect of heating processes, macronutrients composition, and olive ripeness on the new emitted aldehydic compounds. Food Res Int 2018; 106:654-665. [PMID: 29579972 DOI: 10.1016/j.foodres.2018.01.029] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Revised: 12/19/2017] [Accepted: 01/15/2018] [Indexed: 01/09/2023]
Abstract
Heating operation has been applied to Chétoui extra-virgin olive oils (EVOOs) extracted from fruits with several ripening stages (RS). The studied samples, were subjected to microwave and conventional heating. Results showed that heated VOOs after 2.5 h and 7 min of conventional and microwave heating, respectively, gave rise to a drastically decrease of LOX products and allowed the detection of toxic new formed aldehydic volatiles (alkanal: nonanal, alkenals: (Z)-2-heptenal and (E)-2-decenal, and alkadienals: (E.E)-2.4-decadienal), which can be used as markers of VOO degradation. Their abundance in the VOO headspaces depends on their boiling points, the rate of their possible degradation to yield other compounds, on the heating processes and on the rate of macronutrients. The emission rate of the new synthesized volatiles during heating processes was mainly attributed to enzymatic oxidation of some fatty acids. Hexanal, (Z)-2-heptenal, (E)-2-octenal, (E)-2-nonenal, (E,E) and (E,Z)-2,4-decadienal, and (E,E)-2,4-nonadienal, derived from linoleic acid, and heptanol, octanal, nonanal, decanal, (E) and (Z)-2-decenal, (E)-2-undecenal, and (E,E)-2,4-nonadienal, are emitted after degradation of oleic acid. During thermo-oxidation, the ECN44 (LLO, and OLnO), and the ECN46 (OLO, and PLO + SLL) compounds decreased, whereas, the ECN48 (OOO, and PPO), and the ECN50 (SOO) compounds increased when temperature and heating time increased. The several variations of the studied biochemical compounds depend to the heating processes. Ripening stage of olive fruits can be used as a tool to monitor the emission rate of the aldehydic volatiles, but cannot be used for a chemometric discrimination.
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Affiliation(s)
- Imen Oueslati
- Laboratoire de Biotechnologie de l'Olivier, Centre de Biotechnologie de Borj-Cedria, B.P. 901, 2050 Hammam-Lif, Tunisia.
| | - Hédia Manaï
- Laboratoire de Biotechnologie de l'Olivier, Centre de Biotechnologie de Borj-Cedria, B.P. 901, 2050 Hammam-Lif, Tunisia
| | - Mónica Madrigal-Martínez
- CICYTEX- Technological Agri-Food Institute (INTAEX), Government of Extremadura. Avenida Adolfo Suaret s/n, E-06007 Badajoz. Spain
| | - Manuel A Martínez-Cañas
- CICYTEX- Technological Agri-Food Institute (INTAEX), Government of Extremadura. Avenida Adolfo Suaret s/n, E-06007 Badajoz. Spain
| | - Jacinto Sánchez-Casas
- CICYTEX- Technological Agri-Food Institute (INTAEX), Government of Extremadura. Avenida Adolfo Suaret s/n, E-06007 Badajoz. Spain
| | - Mokhtar Zarrouk
- Laboratoire de Biotechnologie de l'Olivier, Centre de Biotechnologie de Borj-Cedria, B.P. 901, 2050 Hammam-Lif, Tunisia
| | - Guido Flamini
- Dipartimento di Farmacia, Via Bonanno 6, 56126 Pisa, Italy
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8
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Wan Z, Li K. Effect of pre-pyrolysis mode on simultaneous introduction of nitrogen/oxygen-containing functional groups into the structure of bagasse-based mesoporous carbon and its influence on Cu(II) adsorption. Chemosphere 2018; 194:370-380. [PMID: 29223116 DOI: 10.1016/j.chemosphere.2017.11.181] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/03/2017] [Revised: 11/13/2017] [Accepted: 11/30/2017] [Indexed: 06/07/2023]
Abstract
A convenient effective microwave pre-pyrolysis treatment to synthesize biomass-based mesoporous carbon with higher nitrogen/oxygen-chelating adsorption for Cu(II) is reported here, in which phosphoric acid impregnated bagasse was used as a microwave absorber and porogen. For comparison, conventional electric-heating pyrolyzed carbon was prepared and doped with nitrogen/oxygen groups. Nitrogen adsorption, scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy (XPS) and batch adsorption were employed to investigate the effects of the two pre-pyrolysis modes on the sample physicochemical and Cu(II) adsorptive properties. The 22-min-microwave-pyrolyzed bagasse mesoporous activated carbon (MBAC, 85.32% mesoporosity) contained 10.52% O, which is 3.94% more than electric-heating pyrolyzed mesoporous activated carbon (89.52% mesoporosity). After electrophilic aromatic substitutions of N/O doping, the former possessed more N (5.83%) and more O (21.40%), confirming that time-saving energy-efficient microwave pyrolysis favors the formation of defective C/O atoms in or at the edges of the graphite layer of MBAC, which are highly active and tend to act as preferred reactive positions for the doping of N/O-containing groups simultaneously compared with conventional electric-heating pyrolysis. These N and O species existed mainly as COOH, OH, NH and NH2 functional groups, and were confirmed by XPS to be active sites for metal binding via electrostatic attraction, hydrogen bonding, a chelate effect and complexation, resulting in the great enhancement of Cu(II) adsorption. Langmuir isotherm and pseudo-second-order kinetic fitting further proved that Cu(II) adsorption by N/O-doped MBAC is ascribed mainly to chemisorption. Therefore, rapid microwave pre-pyrolysis provides a promising route to prepare excellent-performance N/O-doped carbon adsorbents.
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Affiliation(s)
- Zeqing Wan
- College of Engineering, Nanjing Agricultural University, Nanjing 210031, China.
| | - Kunquan Li
- College of Engineering, Nanjing Agricultural University, Nanjing 210031, China.
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9
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Devi S, Wu BH, Chu PY, Liu YP, Wu HL, Ho YP. Studying the effect of microwave heating on the digestion process and identification of proteins. Electrophoresis 2016; 38:429-440. [PMID: 27770443 DOI: 10.1002/elps.201600392] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2016] [Revised: 10/06/2016] [Accepted: 10/12/2016] [Indexed: 11/07/2022]
Abstract
The impact of microwave irradiation on the in-solution digestion processes and the detection limit of proteins are systematically studied. Kinetic processes of many peptides produced through the trypsin digestion of various proteins under microwave heating at 50°C were investigated with MALDI-MS. This study also examines the detection limits and digestion completeness of individual proteins under microwave heating at 50°C and at different time intervals (1, 5 and 30 min) using LC-MS. We conclude that if the peptides without missed cleavage dictate the detection limit, conventional digestion will lead to a better detection limit. The detection limit may not differ between the microwave and conventional heating if the peptides with missed cleavage sites and strong intensity are formed at the very early stage (i.e., less than 1 min) and are not further digested throughout the entire digestion process. The digestion of Escherichia coli lysate was compared under conventional and short time (microwave) conditions. The number of proteins identified under conventional heating exceeded that obtained from microwave heating over heating periods less than 5 min. The overall results show that the microwave-assisted digestion is not complete. Although the sequence coverage might be better, the detection limit might be worse than that under conventional heating.
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Affiliation(s)
- Shobha Devi
- Department of Chemistry, National Dong Hwa University, Hualien, Taiwan
| | - Bo-Hung Wu
- Department of Chemistry, National Dong Hwa University, Hualien, Taiwan
| | - Pei-Yu Chu
- Department of Chemistry, National Dong Hwa University, Hualien, Taiwan
| | - Yue-Pei Liu
- Department of Chemistry, National Dong Hwa University, Hualien, Taiwan
| | - Hsin-Lin Wu
- Department of Chemistry, National Dong Hwa University, Hualien, Taiwan
| | - Yen-Peng Ho
- Department of Chemistry, National Dong Hwa University, Hualien, Taiwan
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Hosseini Koupaie E, Eskicioglu C. Conventional heating vs. microwave sludge pretreatment comparison under identical heating/cooling profiles for thermophilic advanced anaerobic digestion. Waste Manag 2016; 53:182-195. [PMID: 27160636 DOI: 10.1016/j.wasman.2016.04.014] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/21/2016] [Accepted: 04/12/2016] [Indexed: 06/05/2023]
Abstract
This research evaluates whether there is any advantage of selecting one of the thermal methods of sludge pretreatment, conventional heating (CH) and microwave hydrolysis (MW), over another to enhance municipal sludge disintegration and performance of thermophilic anaerobic digestion (AD). For this purpose, a custom-built CH system simulating MW hydrolysis under identical heating and cooling profiles was used. The effects of three main pretreatment parameters including pretreatment method (CH and MW), heating ramp rate (3, 6 and 11°C/min) and final temperature (80, 120 and 160°C) on sludge solubilization and performance of thermophilic batch AD were evaluated. The effects of CH and MW hydrolysis were observed to be similar for sludge disintegration and digester performance (p-value>0.05), while the effects of final temperature and heating ramp rate were proven to be different (p-value<0.05). According to the results, it is essential to apply MW and CH pretreatments under identical experimental condition for an unbiased comparison which supports the findings of the author's earlier study under mesophilic condition. Failing to address this issue explains the significant inconsistency observed among the findings of the previous CH vs. MW comparison studies that were unable to implement identical thermal profiles (between CH and MW) during sludge pretreatment. In comparison with mesophilic AD, thermophilic AD revealed lower biodegradation rate constant at the highest pretreatment temperature tested (160°C), suggesting its higher sensitivity to the inhibitory effects of thermal pretreatment at the elevated temperatures.
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Affiliation(s)
- E Hosseini Koupaie
- UBC Bioreactor Technology Group, School of Engineering, The University of British Columbia, Okanagan Campus, 3333 University Way, Kelowna, BC V1V 1V7, Canada.
| | - C Eskicioglu
- UBC Bioreactor Technology Group, School of Engineering, The University of British Columbia, Okanagan Campus, 3333 University Way, Kelowna, BC V1V 1V7, Canada.
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11
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Jahantigh N, Keshavarz A, Mirzaei M. Hybrid heating systems optimization of residential environment to have thermal comfort conditions by numerical simulation. J Environ Health Sci Eng 2015; 13:50. [PMID: 26052442 PMCID: PMC4458044 DOI: 10.1186/s40201-015-0202-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 05/29/2013] [Accepted: 05/11/2015] [Indexed: 06/04/2023]
Abstract
The aim of this study is to determine optimum hybrid heating systems parameters, such as temperature, surface area of a radiant heater and vent area to have thermal comfort conditions. DOE, Factorial design method is used to determine the optimum values for input parameters. A 3D model of a virtual standing thermal manikin with real dimensions is considered in this study. Continuity, momentum, energy, species equations for turbulent flow and physiological equation for thermal comfort are numerically solved to study heat, moisture and flow field. K - ɛRNG Model is used for turbulence modeling and DO method is used for radiation effects. Numerical results have a good agreement with the experimental data reported in the literature. The effect of various combinations of inlet parameters on thermal comfort is considered. According to Pareto graph, some of these combinations that have significant effect on the thermal comfort require no more energy can be used as useful tools. A better symmetrical velocity distribution around the manikin is also presented in the hybrid system.
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Affiliation(s)
- Nabi Jahantigh
- />Mechanical Engineering Department, University of Zabol, Zabol, Iran
| | - Ali Keshavarz
- />Mechanical Engineering Department, K. N. Toosi University of Technology, Tehran, Iran
| | - Masoud Mirzaei
- />Mechanical Engineering Department, K. N. Toosi University of Technology, Tehran, Iran
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12
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Benlloch-Tinoco M, Kaulmann A, Corte-Real J, Rodrigo D, Martínez-Navarrete N, Bohn T. Chlorophylls and carotenoids of kiwifruit puree are affected similarly or less by microwave than by conventional heat processing and storage. Food Chem 2015; 187:254-62. [PMID: 25977024 DOI: 10.1016/j.foodchem.2015.04.052] [Citation(s) in RCA: 54] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2015] [Revised: 04/11/2015] [Accepted: 04/14/2015] [Indexed: 01/17/2023]
Abstract
The impact of microwave (1000 W - 340 s) and conventional heat (97 °C - 30s) pasteurisation and storage (4, 10, 22 °C for up to 63 d) on total and individual carotenoids and chlorophylls in kiwifruit puree was evaluated. Bioaccessibility of carotenoids, before and after pasteurisation and storage, was also studied. Microwaves and conventional heating led to marked changes in the chlorophyll (42-100% losses) and carotenoid (62-91% losses) content. First- and second-order kinetics appropriately explained the degradation of total carotenoids and chlorophylls over time, respectively. Pasteurised samples showed significantly (p < 0.05) enhanced stability of these pigments, with microwaves (k = 0.007-0.031100 g mg(-1) day(-1) at 4-22 °C) promoting chlorophyll stability to a greater extent than conventional heating (k = 0.0015-0.034100 g mg(-1) day(-1) at 4-22 °C). Bioaccessibility of carotenoids remained (p < 0.05) unaffected by processing and storage. These results highlighted that the pigment composition of microwaved kiwifruit was more similar to that of the fresh fruit and better preserved during storage.
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Affiliation(s)
- María Benlloch-Tinoco
- Universitat Politècnica de València, Food Technology Department, Food Investigation and Innovation Group, Camino de Vera s/n, 46022 Valencia, Spain
| | - Anouk Kaulmann
- Luxembourg Institute of Science and Technology, Environmental Research and Innovation Department, 41 rue du Brill, 4422 Belvaux, Luxembourg
| | - Joana Corte-Real
- Luxembourg Institute of Science and Technology, Environmental Research and Innovation Department, 41 rue du Brill, 4422 Belvaux, Luxembourg
| | - Dolores Rodrigo
- Instituto de Agroquímica y Tecnología de Alimentos (IATA-CSIC), Avda. Agustín Escardino 7, 46980 Paterna, Valencia, Spain
| | - Nuria Martínez-Navarrete
- Universitat Politècnica de València, Food Technology Department, Food Investigation and Innovation Group, Camino de Vera s/n, 46022 Valencia, Spain
| | - Torsten Bohn
- Luxembourg Institute of Science and Technology, Environmental Research and Innovation Department, 41 rue du Brill, 4422 Belvaux, Luxembourg.
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Coromelci-Pastravanu C, Ignat M, Popovici E, Harabagiu V. TiO2-coated mesoporous carbon: conventional vs. microwave-annealing process. J Hazard Mater 2014; 278:382-90. [PMID: 24997254 DOI: 10.1016/j.jhazmat.2014.06.036] [Citation(s) in RCA: 13] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/09/2014] [Revised: 05/23/2014] [Accepted: 06/10/2014] [Indexed: 05/28/2023]
Abstract
The study of coating mesoporous carbon materials with titanium oxide nanoparticles is now becoming a promising and challenging area of research. To optimize the use of carbon materials in various applications, it is necessary to attach functional groups or other nanostructures to their surface. The combination of the distinctive properties of mesoporous carbon materials and titanium oxide is expected to be applied in field emission displays, nanoelectronic devices, novel catalysts, and polymer or ceramic reinforcement. But, their synthesis is still largely based on conventional techniques, such as wet impregnation followed by chemical reduction of the metal nanoparticle precursors, which takes time and money. The thermal heating based techniques are time consuming and often lack control of particle size and morphology. Hence, since there is a growing interest in microwave technology, an alternative way of power input into chemical reactions through dielectric heating is the use of microwaves. This work is focused on the advantages of microwave-assisted synthesis of TiO2-coated mesoporous carbon over conventional thermal heating method. The reviewed studies showed that the microwave-assisted synthesis of such composites allows processes to be completed within a shorter reaction time allowing the nanoparticles formation with superior properties than that obtained by conventional method.
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Affiliation(s)
- Cristina Coromelci-Pastravanu
- Laboratory of Materials Chemistry, Department of Chemistry, "Al. I. Cuza" University, Boulevard, Carol I, No. 11, 700506 Iasi, Romania
| | - Maria Ignat
- Laboratory of Materials Chemistry, Department of Chemistry, "Al. I. Cuza" University, Boulevard, Carol I, No. 11, 700506 Iasi, Romania; "Petru Poni" Institute of Macromolecular Chemistry, 41A, Gr. Ghica Voda Alley, 700487 Iasi, Romania.
| | - Evelini Popovici
- Laboratory of Materials Chemistry, Department of Chemistry, "Al. I. Cuza" University, Boulevard, Carol I, No. 11, 700506 Iasi, Romania
| | - Valeria Harabagiu
- "Petru Poni" Institute of Macromolecular Chemistry, 41A, Gr. Ghica Voda Alley, 700487 Iasi, Romania
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