Search

Summary: This study compared the furan levels and physicochemical properties of various 70 samples of five nuts (peanuts, almonds, cashew nuts, hazelnuts, and sacha inchi) roasted using an air fryer (AF) and microwave oven (MO). In the five nuts, furan levels ranged from 1.11 to 2.39 ng g−1 before roasting. As the AF‐based and MO‐based roasting progressed, the furan levels increased to 6.39–165.52 ng g−1 and 11.47–183.87 ng g−1, respectively. The contents of polyunsaturated fatty acids (linoleic acid and linolenic acid) decreased significantly after roasting but the content of monounsaturated fatty acid (oleic acid) showed only slightly significant differences between the control and roasted nuts. The total phenolic content and antioxidant activity increased by up to 337% and 218% as roasting progressed but decreased slightly when roasting was performed at 180 °C for 20 min in an AF or at 700 or 1000 W for 5 min in an MO. This study provides useful information on furan production and the changes in physicochemical properties such as fatty acid composition, colour, BI, TPC, and antioxidant activity of nuts roasted using an AF or MO. [ABSTRACT FROM AUTHOR]

Domestic microwave ovens offer rapid cooking but face challenges such as non-uniform temperature distribution and hot spots. A novel solid-state heating system, which precisely controls microwave frequency and power, provides a promising alternative to traditional microwave ovens utilizing magnetron systems. This study compared the effects of solid-state microwave cooking on the quality of broccoli, red peppers, and carrots with those of traditional microwave and conventional cooking. The traditional microwave cooking used in this study operated at 2450 MHz, while the solid-state system functioned between 902 and 928 MHz. Weight loss was highest for conventional cooking, reaching a maximum of 34%, whereas microwave cooking resulted in a maximum of 11.65% and solid-state microwave cooking in 17.04%. The total phenolic content obtained through conventional cooking ranged between 61.58 and 116.51 mg GAE (gallic acid equivalents)/100 g dry basis, while microwave cooking resulted in a range of 88.04–110.92 mg, and solid-state microwave cooking achieved values between 76.14 and 122.91 mg. Furthermore, reductions in chlorophyll content were observed to be 68.2%, 25.6%, and 35.7% for conventional, microwave, and solid-state microwave cooking, respectively. Lycopene content after conventional cooking decreased to 224.73 mg/100 g dry basis, compared to 289.55 mg after microwave cooking and 242.94 mg after solid-state microwave cooking. β-carotene content showed a decrease of 14.5% in conventional cooking, while both microwave methods showed an increase of 14.7%. These results suggest that solid-state microwave cooking may have promising positive effects on food quality. [ABSTRACT FROM AUTHOR]

Chlorophyll b quantities of raw (control) and roasted rapeseed samples were specified to be higher than chlorophyll a. Additionally, total phenol, total flavonoid quantities and antioxidant activity (DPPH and FRAP assays) values of roasted powdered and whole rapeseed samples were observed to increase compared to the control. K232 and K270 values ​​of conventional oven roasted, ground and whole rapeseeds were slightly higher than the results in the microwave. The highest K232 value was observed in oil provided from the sample that was powdered and heat treated in conventional oven. The phenolic constituents of ground and whole rapeseeds were partially higher than those of their oils. The dominant fatty acids of the oils extracted from unroasted and roasted rapeseeds were oleic, linoleic, linolenic and palmitic acids in decreasing order. Oleic acid quantities of the oil provided from powdered and whole rapeseeds roasted in microwave and oven were defined as 62.00 and 61.97% to 61.48 and 62.06%, respectively. The main variables of PC1 for rapeseed were dedected as catechin (0.912), coumaric acid (0.840) and ferulic acid (0.733). [ABSTRACT FROM AUTHOR]

In this study, the effects of microwave and oven systems on bioactive properties (total phenolic, total flavonoid, and antioxidant capacity), fatty acids, polyphenols, and mineral contents of raw and roasted “Sarışeker” and “Balyumru” tubers are investigated. Antioxidant activity values of “Sarışeker” tigernut tubers roasted in microwave and oven systems are defined to be between 1.56 (540 W) and 2.57 mmolTE kg−1 (720 W) to 1.57 (80 and 120 °C) and 1.68 mmolTE kg−1 (100 °C), respectively. Gallic acid results of the “Sarışeker” and “Balyumru” tigernut tubers roasted in microwave are specified to be between 5.49 (720 W) and 6.59 mg/100 g (540 W) to 15.83 (900 W) and 21.47 mg/100 g (720 W), respectively. In general, the phenolic component values of the “Sarışeker” tigernut tubers roasted at different temperatures are higher than the “Sarışeker” tigernut samples roasted in the microwave. The oleic, linoleic, and linolenic acid values of the oils obtained from “Sarışeker” tubers roasted in both roasting systems increase compared to the control. The heat treatment has different effects on the contents of different elements of the tigernut tubers. It has been observed that there are significant fluctuations in the amounts of minerals in the structure of foods as a result of the heat treatment applied. [ABSTRACT FROM AUTHOR]

The composite castings of Cu-xW (where; x=5, 10, and 15 wt.%) have been successfully developed by a novel processing route. The concept of microwave hybrid heating is successfully applied in this study and cast samples were developed in a domestic microwave oven with a maximum power of 900 W and at a frequency of 2.45 GHz. The in situ melting and cast samples were developed with in a duration of 07 min of microwave radiation exposure. The microstructure of cast samples developed shows a regular, roughly hexagonal grain growth that resembles cellular proliferation. The recrystallization and grain growth suppression after adding W content in Cu have been revealed. The formation of different phases such as Cu64O and CuWO4 were observed. The Vicker's microhardness value of composite cast samples was observed to increase more than twice of pure copper cast samples. [ABSTRACT FROM AUTHOR]

The objective of this study was to create and characterize an innovative granola, a popular choice in quick breakfasts. The granola samples were sweetened with agave syrup (A), honey (H), and stevia (S) and produced using conventional oven (1) and microwave (2) baking techniques at temperatures of 160°C and 300 W, respectively. Among the samples, H1 exhibited the highest total sugar content (26.64 ng/µL), with fructose being the predominant monosaccharide in A and H samples, whereas saccharose and maltose were more prominent in S‐containing samples. Hydroxymethylfurfural was absent in S2, but its concentrations ranged between 10.52 and 85.78 ppm in the other samples. Linoleic acid constituted nearly 52% of the fatty acid composition in all granolas. In terms of organic acid composition, malic acid ranged between 1189.55 and 2022.95 µg/mL, and citric acid fell within the range of 341.58 and 1824.04 µg/mL. The granola specimens also contained individual phenolic compounds, such as vanillic acid, vanillin, ferulic acid, propyl gallate, and pyrocatechol. Practical Application: This study demonstrates that both baking method and sweetener choice significantly impact the chemical quality attributes of granola, which is a popular breakfast cereal. Microwave baking can be a faster and potentially healthier option, whereas stevia offers a low‐calorie sweetener alternative. Further research is needed to maximize health benefits of granola products. [ABSTRACT FROM AUTHOR]

Placing metals within microwave ovens has been generally viewed as a dangerous practice because of occurrence of violent discharge, but in recent years such discharge phenomenon has attracted increasing attention and has enabled a variety of exciting applications. In this work, we provide a comprehensive review of fundamental understanding of microwave–metal discharge interaction and its state-of-the-art application for nanomaterials synthesis. We introduce the microscopic interaction between different categories of materials and the electric and magnetic field of microwaves. For microwave–metal interaction, we highlight its size-dependence and point out the influence of the oxide layer on the surface of metals. We discuss the required conditions for occurrence of discharge, microscopic formation mechanism, and characteristic features of microwave–metal discharge processes. Through analyzing the influence from the microwave input, discharging metals, and surrounding discharging media, we discuss the strategy for systematical regulation of the discharge process. We describe the applications of the microwave–metal discharge for facile synthesis of various functional nanomaterials including core–shell carbon/metal, metal oxides, metal chalcogenides, intermetallic compounds, metallic nanoparticles and metallic compounds, and organic compounds. Finally, the challenges in precise characterization and dynamic regulation of the discharge process as well as exciting application opportunities are discussed. [ABSTRACT FROM AUTHOR]

In the current study, we examined the effects of boiling cauliflower in a pressure cooker, conventional boiling, conventional heating, and microwave heating on the chemical components, total phenol, flavonoids, antioxidant capacity (DPPH test), phenolic compounds, and mineral contents of cauliflower florets to reveal the differences between these cooking methods. Cauliflower is generally consumed either boiled or cooked in dry heat. In this study, different boiling and dry heat cooking methods were tried to reveal the changes in phytochemical composition and protein and mineral contents of cauliflower florets. Depending on the cooking methods of the cauliflower florets, the total phenolic and flavonoid contents of the cauliflower florets were determined to be between 273.72 (conventional heating) and 731.01 mg GAE/100 g (microwave heating) and 142.02 (conventional heating) and 797.10 mg/100 g (conventional boiling), respectively. The antioxidant capacity results of cauliflowers were found to be between 8.30 (conventional heating) and 33.69 mmol/kg (fresh). Statistically significant differences were detected in the moisture, total phenol, total flavonoid, and antioxidant activity values of cauliflower depending on the cooking techniques applied (p < 0.05). The gallic acid and 3,4-dihydroxybenzoic acid values of fresh and cooked cauliflowers were identified to be between 10.93 (microwave heating) and 194.79 mg/100 g (boiling in pressure cooker) and 17.58 (conventional heating) and 145.80 mg/100 g (boiling in pressure cooker), respectively. In general, the lowest amounts of phenolic compounds were defined in cauliflower samples boiled with a conventional heating system, followed by cauliflower samples cooked with the microwave heating method. Considering the component amounts as a result of cooking, the highest phenolic component amounts were specified in the cauliflower sample cooked by boiling in a pressure cooker. The protein quantities of fresh and cooked cauliflowers were determined to be between 16.11 (fresh) and 19.79% (microwave heating). The K and S contents of fresh cauliflowers and cauliflowers cooked with different blanching methods were specified to be between 19,647.62 (conventional boiling) and 35,130.01 mg/kg (conventional heating) and 3196.54 (boiling in pressure cooker) and 5105.65 mg/kg (microwave heating), respectively. The K, Mg, S, Fe, Cu, Mn, and Zn results of cauliflowers cooked in an oven and microwave were higher than those cooked using the control and boiling methods. [ABSTRACT FROM AUTHOR]

Commercial Brazilian wheat flour was subjected to extrusion, oven, and microwave treatments. The solubility, monomeric and polymeric proteins, and the glutenin and gliadin profiles of the gluten were analyzed. In addition, in vitro digestibility and response against potential celiac disease immune-stimulatory epitopes were investigated. All treatments resulted in low solubility of the polymeric and monomeric proteins. The amounts of insoluble proteins increased from 5.6% in control flour to approximately 10% for all (treatments), whereas soluble proteins decreased from 6.5% to less than 0.5% post treatment. In addition, the treatments affected glutenin and gliadin profiles. The amount of α/β-gliadin extracted decreased after all treatments, while that of γ-gliadin was unaffected. Finally, the potential celiac disease immune stimulatory epitopes decreased in oven and microwave treatment using the G12 ELISA, but no change was observed using the R5 antibody. However, the alteration of the gluten structure and complexity was not sufficient to render a product safe for consumption for individuals with celiac disease; the number of potential celiac disease immune-stimulatory epitopes remained high. [ABSTRACT FROM AUTHOR]

In continuation of the search for effective, economical, and environmental methods of synthesizing the antihistamine agent diphenhydramine, alkylation of dimethylethanolamine by bromo- (or chloro-)diphenylmethane under phase-transfer catalysis (PTC) conditions and in a microwave oven was studied. The efficiencies of a two-phase liquid(liquid system and a solid-phase(liquid system were compared. The quaternary ammonium salt tetrabutylammonium bromide (TBAB) was used as a catalyst. The proposed microwave irradiation was found to be effective and allowed diphenhydramine to be synthesized in a short time in high yield and purity, suggesting that the proposed method could be used in practice. [ABSTRACT FROM AUTHOR]

Carica papaya Linn. is one of the most common plants in almost all tropical countries. Its fruit is widely used as food or an ointment in traditional medicine. It is one of the few tropical fruits to contain glucotropaeolin (benzyl glucosinolate) detected in great quantity, mainly in the seeds of papaya. When cells in plant tissue are damaged, glucotropaeolin is hydrolysed by the enzyme myrosinase to benzyl isothiocyanate. The anticancer activity of this latter compound has been widely evidenced, but the metabolic profile of the papaya seed extracts is not reported in the literature. The objective of this study is to investigate the seed extracts of C. papaya L. by UHPLC-PDA ESI/MS, with and without the inactivation of myrosinase, and compare the recovery of some main components using two different inactivation procedures. The extracts (methanol/water, 60:40, v/v) were studied in negative and positive ionisation modes. Separations were carried out on an Acquity BEH C18 (50 × 2.1 mm i.d.) 1.7 μm analytical column, and 0.02% formic acid in water and acetonitrile was used as the mobile phase at a flow rate of 0.6 mL min−1. Beyond the amino acids and glucotropaeolin already detected in papaya seeds, 4-hydroxybenzoic acid, which has never been detected in papaya seeds with this technique before, was identified. Moreover, mono-, di- and tri-glycosides of 4-hydroxybenzoic acid were putatively assigned. Glucotropaeolin, 4-hydroxybenzoic and tryptophan were quantified in seeds extracted after myrosinase deactivation. These three components were more effectively recovered using an oven than microwave myrosinase inactivation. [ABSTRACT FROM AUTHOR]

Copyright of Nachrichten aus der Chemie is the property of Wiley-Blackwell and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Tiwai onion (Eleutherine americana L. Merr) is renowned for therapeutic properties due to the bioactive constituents, including polyphenol, flavonoid, and tannin. Therefore, this study aimed to characterize water content, ash, fat, protein, polyphenol, flavonoid, tannin, and antioxidant capacity, as well as to observe the functional groups and morphology of dried tiwai powder. The methodology comprised 2 factors, namely harvest age and drying methods. The results showed significant effects of harvest age and drying methods on water, fat, total phenol, total flavonoid, anthocyanin content, and antioxidant capacity, while ash, protein, and tannin content were not significantly affected. In Fourier Transform Infrared Spectroscopy (FTIR) analysis, changes in functional groups were observed, although not significant in wave numbers range of 1,800 - 1,350 and 1,200 - 950 cm-1. Specifically, an increase was observed in signals from C-C, C-O, and C-O-C vibrations. Scanning Electron Microscopy (SEM) at 1000x magnification showed that air drying at 5 months of harvest age produced dense granules, while electric oven and microwave drying of older harvests led to a flatter structure and crumbly texture. [ABSTRACT FROM AUTHOR]

Microwaves have become an essential part of the modern kitchen, but their potential as a reservoir for bacterial colonization and the microbial composition within them remain largely unexplored. In this study, we investigated the bacterial communities in microwave ovens and compared the microbial composition of domestic microwaves, microwaves used in shared large spaces, and laboratory microwaves, using next-generation sequencing and culturing techniques. The microwave oven bacterial population was dominated by Proteobacteria, Firmicutes, Actinobacteria, and Bacteroidetes, similar to the bacterial composition of human skin. Comparison with other environments revealed that the bacterial composition of domestic microwaves was similar to that of kitchen surfaces, whereas laboratory microwaves had a higher abundance of taxa known for their ability to withstand microwave radiation, high temperatures and desiccation. These results suggest that different selective pressures, such as human contact, nutrient availability and radiation levels, may explain the differences observed between domestic and laboratory microwaves. Overall, this study provides valuable insights into microwave ovens bacterial communities and their potential biotechnological applications. [ABSTRACT FROM AUTHOR]

A series of 5-methyl-1,2,4-triazol-3-ones containing salicyl or isatin moieties were synthesized by using conventional and microwave heating techniques. In microwave heating, the compounds were synthesized by using both a monomod microwave reactor and domestic type microwave oven and their results were compared. The synthesized compounds were evaluated for their urease inhibitory activities. Among the synthesized compounds two isatin containing 1,2,4-triazol-3-one derivatives (IC50 = 0.5230±0.0318 and 0.4860±0.0317 µM) showed higher activities than salicyl containing derivatives (IC50 = 0.5451±0.0315 and 0.7181±0.0345 µM), while standard thiourea showed IC50= 0.5027±0.0293 µM activity. [ABSTRACT FROM AUTHOR]

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Lietpak (EU register number RECYC327), which uses the EREMA MPR technology. The input material is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post‐consumer PET containers, including no more than 5% PET from non‐food consumer applications. The flakes are heated in a ■■■■■ reactor under vacuum. Having examined the challenge test provided, the Panel concluded that the ■■■■■ decontamination (step 2), for which a challenge test was provided, is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migration of 0.1 μg/kg food, derived from the exposure scenario for infants, when such recycled PET is used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long‐term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave or conventional ovens and such uses are not covered by this evaluation. [ABSTRACT FROM AUTHOR]

This study optimized the organic matter solubilization of faecal sludge (FS). FS was treated in a microwave oven at varying microwave power and treatment times. Changes in total solids (TS), volatile solids (VS), total chemical oxygen demand (TCOD), and soluble chemical oxygen demand (sCOD) were measured. A response surface methodology (RSM) optimized organic matter solubilization during microwave treatment. A central composite design was employed, and the observed responses were used to fit a second-order response surface model. Microwave treatment at 14,000 kJ/kg. TS reduced FS volume by 58%. The VS/TS ratios remained similar before and after microwave treatment. The solubilization of organic matter (measured by the sCOD/TCOD ratio) increased after microwave treatment, showing an initial linear increase with specific energy followed by a decrease. The highest solubilization was 38%, achieved at a microwave power level of 630 W for 3 min. Organic matter solubilization was more sensitive to contact time than microwave power. RSM determined the optimized conditions to be 617.7 W and 2.4 min, within the experimental design boundaries. These findings align with similar observations from other studies using wastewater sludge. The results suggest that microwave treatment can achieve multiple FS treatment objectives. Optimal operating conditions should be identified if the aim is to solubilize organic matter in FS. [ABSTRACT FROM AUTHOR]

In this study, the effects of microwave (540, 720 and 900 W) and oven (120, 150 and 230°C) roasting techniques on the total phenolics, flavonoids, antioxidant capacity, polyphenolic and fatty acid results of sunflower seed and oils were investigated. Total phenol (except oven 150°C), flavonoid (except oven 120°C) contents and antioxidant activity values of sunflower seeds and oils subjected to oven and microwave heat treatment decreased compared to the control. Total phenolic, total flavonoids and antioxidant activities were higher in MRS oil than ORS oil. Individual phenolic constituent in both seed and oil samples from ORS and MRS showed significant (p < 0.05) changes to the control (non‐roasted seed and its oil). A general increase in the phenolic components of seeds and oils was observed with oven and microwave roasting compared to the control. Oleic acid values (%) of the oil extracted from seeds roasted in oven and microwave systems were recorded to be between 23.76 (120°C) and 29.41% (150°C) to 24.32 (540 W) and 26.10% (720 W), respectively. Linoleic acid values of the oils obtained from seeds roasted in oven and microwave systems varied to be between 57.01 (150°C) and 65.89% (120°C) to 60.70 (720 W) and 65.26% (540 W), respectively. As a result of the applied heat treatment, while the linoleic acid values of the oil samples decreased, an increase was observed in the palmitic, stearic and oleic acid values of the oil. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) are garnering significant interest because of their cost-effective production process and promising potential for future prospects. This paper presents an innovative approach to the fabrication of DSSCs. Further, a comparative study of DSSCs has been carried to evaluate the performance of the solar cells. BaSnO3 (BSO)- and TiO2-based DSSCs were fabricated with the incorporation of a ruthenium-based N719 dye [(Bu4N)2(Ru)(dcbpyH)2(NCS)2]. The sol–gel technique, facilitated by a microwave oven, was employed for the synthesis of the solar cell materials. Subsequently, these materials were deposited on a fluorine-doped SnO2 glass substrate via doctor blade method. Comprehensive analysis of the structural, optical, and electrical properties of the powder and FTO/BSO/N719/electrolyte/Pt and FTO/TiO2/N719/electrolyte/Pt cells was conducted using x-ray diffraction, scanning electron microscopy, UV–Vis–NIR spectroscopy, and current–voltage (J–V) characteristics. The BSO DSSC demonstrated higher incident photon-to-current conversion efficiency in the UV–Vis region and better overall performance than the TiO2-based cell with a similar experimental environment. The BSO-based DSSC exhibited maximum conversion efficiency (ƞ) of 2.64%, whereas the TiO2-based DSSC demonstrated maximum conversion efficiency of 2.19%. [ABSTRACT FROM AUTHOR]

This study aimed to develop a fast procedure for caffeine extraction from roasted coffee beans. The microwave-assisted extraction was carried out in the microwave oven with an operating frequency of 2450 MHz. The response surface methodology based on a Box–Behnken design was used to model and optimize the extraction process. Among the analyzed extraction parameters (factors), the influence of extraction time (2–6 min), liquid-to-solid ratio (5–15 mL/g), and microwave power (336–595 W) were considered, while the yield of extracted caffeine was observed as the response of the system. Water was used as the solvent of choice for the extraction of caffeine. The optimum conditions were as follows: extraction time, 2 min; liquid-to-solid ratio, 15 mL/g; and microwave power, 500 W. In this optimized condition, the expected extraction yield of caffeine was 1.01 g/100 g dry weight (value confirmed by experimental assays). The total energy consumed of 1.7 kWh/100 g of purified caffeine indicated a more energy-efficient procedure by about 1200–15,000 times than the reported procedures. This study showed that caffeine can be quantitatively extracted from roasted coffee beans through a green approach and that the isolated caffeine has a high purity degree, which was confirmed by the UHPLC-ESI-MS/MS method. With this quality, isolated caffeine could be further used as an active ingredient in the food industry, while for pharmaceutical purposes, it must be further purified. [ABSTRACT FROM AUTHOR]

Microwave machining is considered a potential technique to process some nonmetals and a few metals. The technique is found promising at low microwave power. This work analyzes effects of drilling time while drilling stainless steel sheets at low average microwave power. Microwave drilling trials were conducted inside domestic microwave oven at an average microwave power level of 70 W. Interaction of a pointed thoriated tungsten tool (diameter: 1 mm, minimum tip diameter ≈ 0.1 mm) with microwaves triggered metal-microwave discharge plasma column to ablate stainless steel sheet. Tool wear was observed to increase with drilling time, which influenced the plasma column and the resulting quality of drilled holes. Overcut increased with drilling time due to progressive expansion of the plasma column. Similarly, heat-affected zone widened with increase in drilling time. Circularity degraded due to declining uniformity of plasma column with longer drilling. Imaging of plasma column was discussed. Moreover, measures for improving performance parameters are discussed. [ABSTRACT FROM AUTHOR]

This paper describes a method and device for effectively cooling a high voltage transformer inside a microwave oven, with the aim of swiftly removing heat generated during operation, hence improving both the microwave oven's and the transformer's performance and quality. The device incorporates corrugated tank surfaces, electrical connection-lines with protrusions, and epoxy to prevent cooling oil leakage. The transformer is inserted into a designated tank and sealed to separate the coil and core from the outside environment, allowing for better cooling and protection against electrical shock. Additionally, an oil is injected to absorb heat generated by the high temperature of the core and coil. The effectiveness of this method is validated through the finite element method and CFD techniques. Numerical analysis revealed a significant decrease in the maximum temperature rise of the transformer by around 44.2 °C. This finding suggests that transformer oil cooling is a more effective method for controlling temperature rise in microwave ovens compared to traditional cooling methods. [ABSTRACT FROM AUTHOR]

Carbon-based structures have attracted attention due to their unique properties, combining excellent chemical, thermal mechanical, and electrical features. The use of microwave irradiation has been used to produce graphene materials and the identification of optimum synthesis parameters is crucial for the production of high-quality carbon structures. Herein, we describe a detailed temperature study for the production of expanded graphite nanosheets (GNs) via intercalation of sulfuric and nitric acids, followed by a rapid and energy-efficient process of microwave-assisted expansion and exfoliation. The results demonstrate that the proposed methodology was efficient in producing high-quality GNs with a size of approximately 1 nm. The temperature investigation revealed that heat treatment of 800 °C was the best, resulting in a high-quality material, achieving maximum expansion with the lowest weight loss related to thermal degradation. Thus, cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) tests confirmed good electrochemical features of the sample produced at a temperature of 800 °C. [ABSTRACT FROM AUTHOR]

Summary: Total carotenoid amounts of rocket samples were established between 120.56 μg g−1 (fresh) and 130.06 μg g−1 (microwave). In addition, total phenol and flavonoid results of rockets dried in microwave and oven were found between 655.53 (oven) and 1790.96 mg GAE/100 g (fresh) to 254.03 (oven) and 1668.83 mg/100 g (fresh), respectively. Also, radical scavenging activities (DPPH and FRAP) of rocket samples were measured between 7.55 (oven) and 25.45 mmol kg−1 (fresh) to 35.59 (oven) and 66.74 mg g−1 (fresh), respectively. Gallic acid, 3,4‐dihydroxybenzoic acid, catechin and rutin were the main phenolic compounds found in rocket samples. Catechin contents of rockets dried in microwave and oven systems were recorded between 349.60 (oven) and 442.47 mg/100 g (fresh). Gallic acid and 3,4‐dihydroxybenzoic acid amounts of rocket samples were monitored between 52.84 (oven) and 952.15 mg/100 g (fresh) to 30.92 (oven) and 282.15 mg/100 g (fresh), respectively. The protein amounts of rockets were determined between 11.00% (microwave) and 11.60% (oven). P and K values of fresh and dried rockets were found between 3148.36 (oven) and 3752.33 mg kg−1 (fresh) to 39 363.75 (microwave) and 36 883.41 mg/kg (fw), respectively. Also, Ca and Mg results of fresh and dried‐rockets were found between 26 739.33 (microwave) and 29 534.48 mg kg−1 (fresh) to 3125.32 (microwave) and 3431.70 mg kg−1 (fresh), respectively. The highest S (14 665.30 mg kg−1) was detected in rocket sample dried in microwave. [ABSTRACT FROM AUTHOR]

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Guolong (EU register number RECYC323), which uses the EREMA Basic technology. The input material is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post‐consumer PET containers, including no more than 5% PET from non‐food consumer applications. The flakes are heated in a ■■■■■ reactor under vacuum before being extruded. Having examined the challenge test provided, the Panel concluded that the ■■■■■ decontamination (step 2), for which a challenge test was provided, is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migrations of 0.1 and 0.15 μg/kg food, derived from the exposure scenarios for infants and toddlers, when such recycled PET is used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long‐term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave or conventional ovens and such uses are not covered by this evaluation. [ABSTRACT FROM AUTHOR]

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Ecopacking (EU register number RECYC324), which uses the EREMA Basic technology. The input material is ■■■■■ washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post‐consumer PET containers, including no more than 5% PET from non‐food consumer applications. The flakes are heated in a ■■■■■ reactor ■■■■■ before being extruded. Having examined the challenge test provided, the Panel concluded that the ■■■■■ decontamination (step 2), for which a challenge test was provided, is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migrations of 0.1 and 0.15 μg/kg food, derived from the exposure scenarios for infants and toddlers, when such recycled PET is used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long‐term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave or conventional ovens and such uses are not covered by this evaluation. [ABSTRACT FROM AUTHOR]

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process Palamidis (EU register number RECYC325), which uses the EREMA Basic technology. The input material is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post‐consumer PET containers, including no more than 5% PET from non‐food consumer applications. The flakes are heated in a ■■■■■ reactor under vacuum before being extruded. Having examined the challenge test provided, the Panel concluded that the ■■■■■ decontamination (step 2), for which a challenge test was provided, is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migrations of 0.1 and 0.15 μg/kg food, derived from the exposure scenarios for infants and toddlers, when such recycled PET is used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long‐term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave or conventional ovens and such uses are not covered by this evaluation. [ABSTRACT FROM AUTHOR]

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids (CEP) assessed the safety of the recycling process KGL (EU register number RECYC326), which uses the EREMA Basic technology. The input material is hot caustic washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post‐consumer PET containers, including no more than 5% PET from non‐food consumer applications. The flakes are heated in a ■■■■■ reactor under vacuum before being extruded. Having examined the challenge test provided, the Panel concluded that the ■■■■■ decontamination (step 2), for which a challenge test was provided, is critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migrations of 0.1 and 0.15 μg/kg food, derived from the exposure scenarios for infants and toddlers, when such recycled PET is used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long‐term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave or conventional ovens and such uses are not covered by this evaluation. [ABSTRACT FROM AUTHOR]

Microwave-assisted extraction (MAE) treatments seem to be a promising sample preparation strategy to isolate nanomaterials (NMs) from environmental samples prior to single particle inductively coupled plasma mass (spICP-MS) determination. Nevertheless, because previous studies make use of domestic microwave ovens (DMOs), several shortcomings arise that compromise the analysis such as lack of control of experimental variables, limited operating conditions, and uncontrolled sample heating leading to irreproducibility issues. The goal of this work is to adapt previously developed MAE treatments for soil and air filters with the DMO apparatus to state-of-the-art scientific microwave ovens (SMOs) in order to standardize current analytical protocols for NM characterization. Results show that, by working with an SMO, non-labile metallic NMs (Pt-AuNPs) are quantitively extracted from soil and air filter samples unaltered in 10 min and 6 min, respectively, at 1200 W by using 10 mL of NaOH 0.1 M solution. The use of a SMO system allows improving accuracy (above 10% of the particle recovery), precision (above 5% of the RSD) and sample throughput (above 4-fold) when compared to the DMO ones. According to these findings, MAE seems to be a powerful strategy for routine analysis of non-labile NMs in environmental samples. [ABSTRACT FROM AUTHOR]

Microwave applications, such as microwave ovens and mobile phones, are ubiquitous and indispensable in modern society. As the utilization of microwave technology is becoming more widespread, the effects of microwaves on living organisms and physiological processes have received increased attention. This study aimed to investigate the effects of microwaves on calcium carbonate biomineralization as a model biochemical process. A magnetron oscillator was used to generate 2450 MHz microwaves because magnetrons are relatively inexpensive and widespread. We conducted transmission electron microscopy (TEM), atomic force microscopy (AFM), TEM-electron energy-loss spectroscopy (EELS), dynamic light scattering (DLS), and high-performance liquid chromatography (HPLC) measurements to analyze the calcium carbonate precipitates. Our findings showed the formation of string-like precipitates of calcium carbonate upon microwave irradiation from one direction, similar to those obtained using a semiconductor oscillator, as reported previously. This implied that the distribution of the frequency had little effect on the morphology. Furthermore, spherical precipitates were obtained upon microwave irradiation from two directions, indicating that the morphology could be controlled by varying the direction of microwave irradiation. Magnetrons are versatile and also used in large-scale production; thus, this method has potential in medical and industrial applications. [ABSTRACT FROM AUTHOR]

3D-printable composites have become an attractive option used for the design and manufacture of electrochemical sensors. However, to ensure proper charge-transfer kinetics at the electrode/electrolyte interface, activation is often required, with this step consisting of polymer removal to reveal the conductive nanofiller. In this work, we present a novel effective method for the activation of composites consisting of poly(lactic acid) filled with carbon black (CB-PLA) using microwave radiation. A microwave synthesizer used in chemical laboratories (CEM, Matthews, NC, USA) was used for this purpose, establishing that the appropriate activation time for CB-PLA electrodes is 15 min at 70 °C with a microwave power of 100 W. However, the usefulness of an 80 W kitchen microwave oven is also presented for the first time and discussed as a more sustainable approach to CB-PLA electrode activation. It has been established that 10 min in a kitchen microwave oven is adequate to activate the electrode. The electrochemical properties of the microwave-activated electrodes were determined by electrochemical techniques, and their topography was characterized using scanning electron microscopy (SEM), Raman spectroscopy, and contact-angle measurements. This study confirms that during microwave activation, PLAs decompose to uncover the conductive carbon-black filler. We deliver a proof-of-concept of the utility of kitchen microwave-oven activation of a 3D-printed, free-standing electrochemical cell (FSEC) in paracetamol electroanalysis in aqueous electrolyte solution. We established satisfactory limits of linearity for paracetamol detection using voltammetry, ranging from 1.9 μM to 1 mM, with a detection limit (LOD) of 1.31 μM. [ABSTRACT FROM AUTHOR]

This work highlights using a domestic microwave oven to determine moisture in fish tissues. Also, it compares it with other gravimetric methods established employing a conventional oven (AOAC) and infrared radiation. The optimization of the microwave method was performed utilizing a two-level full factorial design. The AOAC method, which uses a temperature of 105 °C, requires 130 min for the analysis, while the microwave method can be done in 2 min. Intraday and interday tests evaluated the precision of both methods. The determination of the moisture of the fishes Cynoscion acoupa, Argyrosomus regius, Carassius auratus, Sardinella longiceps, Thunnus, Merluccius, Caranx latus, and Brachyplatystoma vaillantii was performed using the microwave and AOAC methods. The analysis of variance and the paired t-test showed no significant differences in the results obtained using these two methods. Also, moisture in other fish tissues was quantified using microwave radiation. [ABSTRACT FROM AUTHOR]

Microwave-assisted rock breaking is a new and promising technology for the tunneling and drilling industry. Minerals in rocks have an important influence on the effect of microwave-assisted rock breaking. In this paper, common minerals in rocks such as potash feldspar (hereafter referred to as K-feldspar), calcite and pyroxene were selected as samples, and a lot of microwave irradiation tests were carried out by using a hamilab-v1500 microwave oven. The mass, strength and microstructure of the rock samples were tested before and after microwave irradiation. The change law of the mineral mass, strength and microstructure with regard to temperature was analyzed, and the influence mechanism was discussed. The results show that the strength of K-feldspar increases from 20 °C to 400 °C but decreases significantly when it is higher than 400 °C; the strength of pyroxene increases from 20 °C to 600 °C but decreases when it is higher than 600 °C; the strength of calcite decreases with the increase in temperature. As for the weakening pattern, pyroxene shows drawstring, step and flow with the increase in temperature, but K-feldspar and calcite show that failure occurs along the cleavage plane of the crystal structure. The higher the temperature of microwave irradiation, the finer the pattern at the fractured zone is, and the more fragmented it becomes; the loss of mineral mass increases with the increase in the temperature of microwave irradiation. [ABSTRACT FROM AUTHOR]

In this study, the effects of microwave-assisted foam-mat drying methods on physical, flow, energy consumption and thermo-physical properties were investigated to produce functional orange powder. In the study, modified temperature-controlled microwave (MTCM) and microwave (M-540,720 W) drying methods were used. The drying rates of the drying processes varied between 3.84 × 10−5 and 2.64 × 10−4 g moisture/g dry base minute. Effective diffusion values were determined between 1.69 and 5.00 × 10−10 m2/s. The SMER values of the drying processes were determined between 0.0019 and 0.089 kg/kWh and the SEC values were between 11.29 and 538.80 kWh/kg. Drying processes did not preserve the color value of the greyhound statistically (p > 0.05). The bulk density of the powder varied between 0.46 and 0.69 g/ml and tapped density values between 0.46 and 0.73 g/ml. CI and HR values were determined between 8.82 and 13.16% and 1.10–1.16%, respectively. Micro-capsulating was found between 99.44 and 99.88%. The moisture content of the powder was determined as 0.10–1.72%. Specific heat 837.00–846.00 J/kgK, thermal diffusivity 8.10 × 10−8–3.14 × 10−7 m2/s, thermal conductivity 0.05–0.25 W/mK and density 694.72–839.41 kg/m3 were determined. [ABSTRACT FROM AUTHOR]

The oil amounts of raw and roasted mustard seeds were reported between 12.05 (control) and 16.30% (oven). Total phenolic and flavonoid amounts of untreated (control) and roasted mustard seeds were recorded to be between 473.90 (control) and 569.96 mgGAE/100 g (oven) to 345.48 (control) and 479.76 mg/100 g (microwave), respectively. Antioxidant capacity results of untreated and roasted mustard seeds were determined to be between 6.71 (oven) and 6.97 mmol/kg (control). Total phenolic and flavonoid amounts of oven-roasted seeds were higher than those of control and microwave-roasted seeds. L* values of mustard seeds varied between 35.04 and 65.52. Heat treatment caused a decrease in L* values. The lowest L* value was observed in the sample dried in conventional oven. The quantitative values of gallic and 3,4-dihydroxybenzoic acids of mustard seeds were recorded to be between 8.47 (control) and 117.31 mg/100 g (microwave) to 2.16 (control) and 11.79 mg/100 g (microwave), respectively. Erucic acid values of the oils extracted from raw and roasted mustard seeds were reported between 41.38 (control) and 42.81% (microwave). Oleic and linoleic acid amounts of mustard oils differed between 26.06 (microwave) and 26.90% (control) and between 13.08 (oven) and 13.98% (control), respectively. The oven roasting system had the most effect on the element and protein contents of the seeds, followed by the microwave in decreasing order. As with the bioactive components of the seeds, the amounts of phenolic constituents of roasted mustard seeds increased significantly compared to the control. [ABSTRACT FROM AUTHOR]

The objective of this study was to evaluate the effect of different reheating methods and conditions on the proximate composition, mineral content, oil quality, and functional and microbiological properties of cow meat. For this, a survey was carried out to identify the reheating methods used in the community. For this study, 8.6 kg of raw beef was used and group 1 (500 g) served as raw control. The remaining 8.1 kg was boiled for 30 min in 5 L of water. Four hundred grams of boiled beef was removed and served as cooked control (group 2). The remaining 3688 g was divided into four groups of 922 g, which were, respectively, divided into subgroups of 307 g. The four sets of subgroups were, respectively, reheated by boiling, frying, microwaving and oven roasting for 3 days. Reheating was done three times a day and samples were collected at the end of each day for further analysis. Changes in proximate composition, mineral content, oil quality, functional properties, and microbiological count were evaluated using standard methods. Results showed that frequent reheating of food was the most used preservation method of cooked food, and boiling and steaming were the most used methods. Reheating time significantly reduces the protein, mineral content, and oil quality of cow meat in general. For the functional properties, reheating methods/conditions generally increased the water‐holding capacity, loose and packed bulk densities as well the pH of the meat. Reheating by frying increased the porosity and Hausner ratio of the meat powder while all the reheating treatments reduced the swelling capacity and titratable acidity of cow meat powder. Generally, the reheating methods and duration significantly reduced the bacterial count of cow meat powder. Cow meat should not be reheated for more than 2 days in order to preserve its physiochemical properties. [ABSTRACT FROM AUTHOR]

Climate change is characterized by shifts in temperature and climate patterns. Constructing new high-rise environments using materials that incorporate agro-industrial waste can help mitigate this impact without compromising technological properties. This study produced vitreous foams intended to replace natural aggregates in lightweight concrete partially. These foams were sintered in a microwave oven at temperatures of 750 °C, 800 °C, and 850 °C, utilizing glass powder and sugarcane bagasse ash as raw materials. The homogenization and preparation of these materials were conducted through a mechanical pelletization process, employing a constant rotation engine at approximately 40 rpm. The efficacy of microwave sintering was assessed by comparing the outcomes with those from sintering in a conventional electric muffle furnace under identical conditions. The results indicated that the microwave-sintered vitreous foams exhibited the following values for apparent density (≤0.30 g/cm3), porosity (86% to 94%), and compressive strength (0.48 MPa to 0.58 MPa), which align with the global standards for commercial vitreous foams. The microwave sintering route proved to be economically feasible by reducing sintering time and, consequently, energy costs, without sacrificing technological properties. The materials produced in this study offer a promising solution to minimize the environmental impact associated with constructing new buildings, particularly tall structures. Additionally, they support the circular economy by converting waste into valuable by-products. [ABSTRACT FROM AUTHOR]

Lost-wax glass casting, an esteemed yet technically demanding art form, traditionally relies on specialized, costly kiln equipment, presenting significant barriers to artists regarding equipment affordability, energy efficiency, and the technical mastery required for temperature control. Therefore, this study introduces an innovative approach by integrating a microwave kiln with standard household microwave ovens, thus facilitating the lost-wax glass casting process. This methodological adaptation allows artists to employ readily available home appliances for glass creation, significantly reducing the process's cost and complexity. Our experimental investigations reveal that, by using a 500W household microwave oven for heating, the silicon carbide (SiC) in microwave kilns can efficiently absorb microwave energy, allowing the kilns to reach temperatures exceeding 700 °C, a critical threshold for casting glass softening. We further demonstrate that by adjusting the number of heating cycles, producing high-quality, three-dimensional(3D) glass artworks is feasible, even for large-scale projects. In addition, the microwave kiln can be used as an effective cooling tool to uniformly cool the formed casting glass. This study presents a possible alternative to conventional kiln technology and marks a paradigm shift in glassmaking, offering a more accessible and sustainable avenue for artists and practitioners. [ABSTRACT FROM AUTHOR]

Asphalt pavements are prone to cracking in low-temperature environments, and microwave heating (MH) can heal the cracks effectively. This research mainly investigates the different MH effects on the self-healing properties of asphalt mixtures. With this objective, the three-point splitting test is conducted to generate the cracks. A microwave oven is employed to heat the samples, and a thermal camera measures the surface temperature. Results indicate that heating power and time show a positive linear correlation with healing efficiency, and the HI of the samples can reach over 80%. The HI of the samples decreases with the heating cycle, but the sample with reasonable power and time still has a HI higher than 70% after 5 cycles. The temperature peaks on thermal images indicate that uneven heating exists during heating, but the heating uniformity is within an acceptable range. The healing efficiency level (HEL) suggests that asphalt mixtures have very low inefficient healing behavior if the heating time is below 45 s, but HEL can reach 86.14% at 700 W after 60 s. Furthermore, although the HI of strength shows ideal results, the recovery of other crack parameters, including stiffness, fracture energy, flexible index, and crack resistance index, are not satisfactory. [ABSTRACT FROM AUTHOR]

The EFSA Panel on Food Contact Materials, Enzymes and Processing Aids assessed the safety of the recycling process Martogg Group (EU register number RECYC321), which uses the EREMA Advanced technology. The input material is ■■■■■ washed and dried poly(ethylene terephthalate) (PET) flakes originating from collected post‐consumer PET containers, including no more than 5% PET from non‐food consumer applications. The flakes are heated in continuous reactors ■■■■■ before being extruded. Having examined the challenge test provided, the Panel concluded that the continuous decontamination steps (Steps 2 and 3), for which a challenge test was provided, are critical in determining the decontamination efficiency of the process. The operating parameters to control the performance of this step are temperature, pressure and residence time. It was demonstrated that this recycling process is able to ensure a level of migration of potential unknown contaminants into food below the conservatively modelled migration of 0.1 μg/kg food derived from the exposure scenario for infants when such recycled PET is used at up to 100%. Therefore, the Panel concluded that the recycled PET obtained from this process is not of safety concern when used at up to 100% for the manufacture of materials and articles for contact with all types of foodstuffs, including drinking water, for long‐term storage at room temperature or below, with or without hotfill. Articles made of this recycled PET are not intended to be used in microwave or conventional ovens and such uses are not covered by this evaluation. [ABSTRACT FROM AUTHOR]

This paper presents a design scheme of a Novel Flattened Magnetron for Household Microwave Oven, which makes a breakthrough in the magnetic circuit of the existing magnetron and adopts the symmetrical enhanced magnetic circuit design scheme. Magnetron width has been successfully reduced from 80 mm to 50 mm. The reduction is up to 37.5%. Based on the size of the flattened magnetic circuit system, the theory of magnetron noise, and the knowledge of LC low-pass filters, a filtering structure for the flattened magnetron is proposed. Electromagnetic simulation shows that the magnetron with the new magnetic circuit structure can still meet the design specifications of the magnetron used in the existing microwave oven. An experiment was conducted to verify the proposed design's performance, and it was found to be similar to the existing conventional magnetron. [ABSTRACT FROM AUTHOR]