Microwave Treatment Research Articles

Microwave‐Assisted Fabrication of Highly Crystalline, Robust COF Membrane for Organic Solvent Nanofiltration

AbstractFabrication of crystalline, robust covalent organic framework (COF) membranes based on disorder‐to‐order strategy is promising yet highly challenging. Herein, a microwave‐assisted method for fabricating COF membranes is proposed. Initially, monomers polymerize rapidly on the surface of porous Al2O3 substrate at room temperature to form an amorphous pristine membrane. Subsequently, a microwave field is exerted to trigger fast crystallization, acquiring a crystalline COF membrane within 60 min. The amorphous pristine membrane exhibits a high dissipation factor, indicating excellent microwave absorption capability, which accelerates the dynamic reversible reactions during the microwave treatment and thus ensures a rapid transition from the amorphous to the crystalline state. Owing to the high‐crystallinity and robust structure, the COF membranes exhibit high rejection rates for solute molecules with molecular weights exceeding 700 Da (e.g., Evans blue: 98.7%) and high solvent permeance for organic solvents (e.g., ethanol: 87.8 Lm−2h−1 bar−1, n‐hexane: 222.3 Lm−2h−1 bar−1). Surprisingly, the COF membranes exhibit superior mechanical properties, with Young's modulus of 33.91 ± 3.94 GPa, outperforming previously reported polycrystalline COF membranes and are close to those for inorganic zeolite membranes. The microwave‐assisted COF crystallization method opens a new avenue to fabricating a variety of crystalline membranes for advanced separations.

Effect of the microwave treatment on anti-nutrients of soybeans

BACKGROUND: Soybeans contain anti-nutrients that have to be inactivated before being used as feed for livestock and poultry. AIM: Obtaining the new data on the effect of the heat treatment on soybeans. MATERIALS AND METHODS: Soybeans of the Dongsheng 22 and SK Alta varieties were processed with micronization, autoclaving and microwaves in the developed microwave unit. RESULTS: After micronization, the decrease in total starch was 10–16%, after autoclaving and microwave treatment — 15–17%. The three kinds of treatment did not have a significant effect on total phenolic content. The content of flavonoids increased by 7–9% after autoclaving and micronization and by 16% after microwave treatment. When micronizing and autoclaving soybeans, no changes in antioxidant activity were observed, but with microwave treatment, it increased by 3–5%. The decrease in trypsin inhibitor activity was 80% after microwave treatment and 73–79% after micronization and autoclaving. The tannin content was reduced by 10% with microwave treatment and by 7–9% after micronization and autoclaving. The decrease in phytic acid content was 43–45% and repeated for all kinds of treatment. CONCLUSION: The reduction of antinutrients after micronization, autoclaving and microwave processing ensures the use of soybeans for feed. Milder temperature conditions and cyclic processes of heating and cooling during microwave processing increase the safety of soybeans. The higher heating rate and low energy costs of microwave processing ensure economic feasibility.

Improving phosphorus availability in sewage sludge ash through a novel microwave‐based technology

AbstractThis work is connected with the increasing demand for fertilizers and the associated supply risks and market volatility in the European Union (EU). It highlights the reliance on phosphorus from Moroccan phosphate rocks and the environmental issues stemming from the overuse of phosphate‐based fertilizers. The paper suggests a shift in perspective, viewing waste as a valuable resource. Specifically, it explores the potential of recycling phosphorus from sewage sludge ash, which contains a high phosphorus concentration. The focus is on comparing two methods of phosphorus extraction from sewage sludge ashes: classical wet‐chemical extraction and a new microwave‐based technology. There is an increase in phosphorus bioavailability with the microwave treatment, making it a promising approach for waste management. An initial economic evaluation suggests that the microwave method is highly competitive, especially when compared with wet‐chemical extraction technologies. The resulting material from the microwave treatment is classified as a straight solid inorganic macronutrient fertilizer according to EU regulations.

Enhancing Shelf‐Life of Bael Beverage Through Various Pasteurization Techniques: A Comparative Study at 25°C and 4°C With Thermal, Pulsed Light, and Microwave Treatments

ABSTRACTThe influence of thermal (95°C, 5 min), pulsed light (PL, 1.64 kJ/cm2 available fluence) and microwave (MW, 2 kW, and 16 min ≈ 90°C final temperature) treatment on various quality attributes and shelf‐life of bael (Aegle marmelos) beverage was investigated. The quality parameters under consideration included microbial growth, enzyme activity, bioactive components, sensory quality, and physicochemical properties. Effects of different packaging materials (ethyl vinyl alcohol (EVOH) and multilayered (ML) pouches) and storage temperatures (25°C and 4°C) were also explored. The rate of sample deterioration, loss of bioactive components, and sensory qualities increased with higher storage temperature. MW and thermal processing showed better storage stability based on the minimum microbial counts, enzyme activities, and minimal changes in soluble solids. Least sedimentation was seen in thermally treated samples. MW treatment was better in preventing alterations in pH and titratable acidity (at 25°C), reducing sugars, browning, and sensory acceptance. On 50th day at 4°C, higher total phenolic content (59%–64%), antioxidant capacity (69%–72%), and total carotenoid content (136%–139%) were obtained with the PL treatment. For both packaging materials, a shelf‐life of 40–50 days (as per aerobic mesophile count ≤ 4.0 log CFU/mL) and 30 days (as per overall sensory acceptability > 5) at 4°C was obtained for thermal and microwave. As per AM count, shelf‐life of PL irradiated beverages was 40 days, and according to sensory acceptability, it was 30 days. Overall, MW processed beverages stored in ML‐pouches and at 4°C exhibited better shelf life and storage quality.

Multi-stage evolution of pore structure of microwave-treated sandstone: Insights from nuclear magnetic resonance

Microwave fracturing has great potential in improving the efficiency of hard rock breaking. However, the pore evolution, which can be regarded as the damage accumulation and progressive failure of the rock subjected to microwave irradiation, remains unclear. In this study, nuclear magnetic resonance (NMR) is employed to investigate the pore evolution and fracture mechanism of the sandstone under different microwave power levels. The results show that the pore evolution of the specimens, including distribution of pore size, the weight in volume of various-sized pore, and porosity, exhibits different changing trends under various microwave power levels. The pore evolution of the specimens under microwave irradiation can be categorized into four phases: overall pore expansion, localized pore closure in the internal region, micro-cracks propagation induced by thermal stress, and macro-cracking (or melting). Moreover, pore evolution also plays a crucial role in the decomposition and evaporation of bound water, particularly when the specimens experience fractures triggered by thermal stress induced by the microwave treatment (TSIMT). The employing of NMR imaging (NMRI) description also provides an auxiliary and effective illustration on the pore evolution of the specimens under microwave irradiation. Finally, the mechanism of microwave-assisted rock breaking under different power levels is comprehensively discussed based on the NMR results from a microscopic perspective. It is anticipated that the findings of this study can provide valuable insights for enhancing the efficiency of microwave-assisted rock breaking.

Self-healing Cold Mix Asphalt Containing Steel Slag: A Sustainable Solution to Cleaner Production

Cold-mix asphalt, produced at ambient temperatures, generates significantly lower CO2 emissions compared to hot-mix asphalt, which requires high-temperature mixing and compaction. However, concerns have arisen regarding the lower durability of cold-mix asphalt when exposed to various environmental stressors, leading to the formation of cracks. This paper explores the benefits of a hybrid application of coarse and powdered slag to enhance crack healing in cold-mix asphalt through the use of microwave radiation. To do so, we quantified extent of microwave-induced healing in dry, wet and freeze-thaw conditioned cold mix asphalt containing steel slags. Latter healing is facilitated by heat generated via absorption of electromagnetic waves. Heat distribution within the specimens and crack zone found to be more uniform when the coarse slag (>4.75mm) was supplemented with slag powder (∼0.075mm) as evidenced by thermography analysis. It was further found that freeze-thaw conditioned specimens significantly benefited from microwave-induced healing as evidenced by a 74% recovery in semi-circular bending strength. This enhancement is attributed to the increased diffusion and contact area at heated crack surfaces. Overall, microwave treatment of cold mix asphalt specimens showed an increase in binder wettability and aggregate coating, resulting in improved performance. Notably, the most significant improvements were observed in the stiffness modulus, with increases of 23%, 46%, and 70% for dry, wet, and freeze-thaw conditioned specimens, respectively. Study outcomes support the vision toward the NetZero carbon emission pavements by promoting the durability of cold-mix asphalt to be a viable alternative to hot-mix asphalt.

THE EFFECT OF DİFFERENT PROCESSİNG METHODS ON AMYGDALİN LEVELS AND SOME PHYSİCOCHEMİCAL PROPERTİES OF APRİCOT KERNELS

Apricot seeds, particularly bitter seeds, pose health risks due to their cyanogenic glycosides content. Therefore, determining the amount of amygdalin in seeds is important for the food industry. In this study, the amygdalin content of sweet apricot varieties Hacıhaliloğlu and Kabaaşı, as well as bitter apricot (zerdali), was determined using LS-MS/MS devices. Methods to reduce the amygdalin levels in raw apricot seeds to safe consumption limits were established. The treatments to remove bitterness included sodium bicarbonate alkalinization (4-10% NaHCO3 for 7-15 min), ultrasonic waves (30-50°C for 30-60 min), microwave (240W-560W for 2-5 min), and roasting (120-160°C for 10-20 min). After all treatments, samples were analyzed for fat content, protein, amygdalin content via HCN, antioxidant activity, phenolic compounds, and color values (L, a*, b*, Chroma, Hue) using Soxhlet extraction. The fat content (42.99, 44.35, 40.75 ), protein content (34.14, 30.36, 29.27), and hydrocyanic acid content (mg/kg) (24.56, 30.31, 1630.66) of Hacıhaliloğlu, Kabaaşı, and zerdali varieties were found, respectively. Among the methods used to reduce or eliminate the amygdalin content of raw apricot seeds, roasting emerged as the most effective. For raw zerdali seeds, the amygdalin content was 27.64 mg/g, which decreased to 9.77 after 10 min of roasting at 160°C. In terms of total phenolic content, sweet and bitter seeds had similar values. The antioxidant activity (mg TE/100g) was 82.59 for raw zerdali seeds, with the lowest being for sodium bicarbonate (81.72), ultrasonic (57.5), microwave (52.65), and roasting (97.04) treatments.

Performance enhancement, life cycle assessment, and feature analysis of wheat starch-based NaCl-binder as a sustainable alternative to OPC mortar

The primary aim of this investigation is to advance the properties of an innovative and sustainable wheat starch-based NaCl-binder (WSB) material. The scope encompasses the material's ecological and structural applications and potential for paving usage. The creation of hydrophobic and environmentally friendly WSB samples under microwave curing conditions was achieved by using a salt mortar with varying sizes of salt grains, water, and wheat starch as a binding agent. This study investigated the effects of curing time, water and starch amounts, and salt particle size on strength, modulus of rupture, and modulus of elasticity. Additionally, XRD, XRF, and SEM analyses were carried out to assess the chemical characteristics of WSB and the bonding between its particles. The mix design with the highest compressive strength, which consisted of 1 wt% starch, 8 min of microwave treatment, and 10 wt% water, attained a strength of 25.27 MPa. Furthermore, coconut oil was employed to effectively make the samples water-resistant. Following different guidelines, WSB could be categorized as structural concrete and utilized for structural and paving bricks. A vital aspect of this study is the exceptional environmental performance of WSB as a structural material, highlighting its originality and importance.

Effects of microwave treatment on structural and functional properties of germinated corn starch.

Measuring the germination index of corn, and gelatinization index, thermodynamic properties, long-range structure, short-range structure and particle morphology of corn starch, the study aimed to investigate the effects of different microwave (MW) treatment on the structural and functional properties of germinated corn starch. The results indicated that after appropriate MW treatment, the germination indices (germination rate, germination potential, sprout length and sprout weight) of germinated corn starch were improved after 7 days of germination. In addition, MW treatment also affected the structure of germinated corn starch. MW treatment could reduce the relative crystallinity of starch, but did not change the crystal type and the peak position of each absorption peak in Fourier transform infrared spectra. In addition, rapid visco-analysis and differential scanning calorimetry results showed, respectively, that MW treatment decreased the peak viscosity of germinated corn starch and increased the gelatinization temperature. Finally, MW treatment made the starch surface become rough, destroyed the starch particle structure and produced random cracks and voids. Overall, the present study proves that appropriate MW treatment is an effective measure for the modification of germinated corn starch, and provides a theoretical basis for the application of MW technology in germinated corn products. © 2024 Society of Chemical Industry.

Green extraction of colorants from achiote seeds for dyeing mordanted nylon fabric

The extraction of sustainable colorants requires energy efficient technology for their eco-application in different fields. For current study on nylon fabric, the natural dye from achiote (Bixa orellana) has been extracted in aqueous and acidic media and valorized through microwave (MW) radiation. MW treatment has been applied to both extracted biomolecule and nylon fabric up to 10 min and the dyeing variables were optimized using statistical model. For getting permanent shades eco-salts of Al (III) and Fe (II) as well as biomolecules from waste plant materials (pomegranate and myrobalan) were utilized. ISO methods for assessment of colorfast shades have been employed. It was found that for nylon, by MW treatment of the dye material and polymeric stuff for 4 min, good color yield in terms of color strength (K/S=29.52) is obtained. It has been observed that when MW treated extract (pH=6) is employed at 40 °C for 55 min, good quality shade of high strength is obtained by using selected amounts of eco-chemical and organic molecules. It is concluded that MW treatment should be given to dyeing process for getting effective yield and tannin based green molecules as organic mordant can used to make dyeing process more ecofriendly and sustainable.

Study on Quality and Starch Characteristics of Powdery and Crispy Lotus Roots.

Nine varieties of lotus root (Suining, Xinhe, Zaohua, Zhonghua, L0014, L0013, Cuiyu, L0011, and Zhenzhu) were selected as the research materials to compare their differences in physical, chemical, and starch characteristics before and after boiling, frying, and microwaving. The results showed that Zhenzhu, Xinhe, L0013, Cuiyu, and Zhonghua belong to the crispy lotus root type, while L0011, L0014, Zaohua, and Suining belong to the powdery lotus root type. Furthermore, the nine varieties were characterized for their starch by optical micrograph (OM), polarized micrograph (PM), scanning electron micrograph (SEM), attenuated total reflection Fourier-transform infrared spectroscopy (ATR-FTIR), X-ray diffraction (XRD), carbon-13 cross-polarization/magic angle spinning nuclear magnetic resonance (13C CP/MAS NMR), and differential scanning calorimetry (DSC). The starch granule of powdery lotus root appeared to be larger than that of crispy lotus, and ATR-FTIR studies revealed that the outer layer of starch granules from nine different varieties of lotus root had a highly organized structure. Moreover, XRD and 13C CP/MAS NMR analyses revealed that starch from eight lotus varieties (Suining, Xinhe, Zaohua, Zhonghua, L0014, L0013, Cuiyu, L0011) belong to the A-crystal type, while starch from Zhenzhu belongs to the CA-crystal type. The starch from powdery lotus root exhibited higher crystallinity, as well as increased gelatinization temperature and enthalpy, indicating that its crystal structure was relatively superior compared to that of crispy lotus starch. The short-range order degree, crystallinity, gelatinization temperature, and heat enthalpy of lotus starch decreased after boiling and frying but increased to varying extents after microwaving. Additionally, the heat resistance and stability of starch particles from crispy lotus root were improved after microwave treatment.

Judicious combinations of gravity, magnetic, electrostatic separators and microwave heat energy on recovery of ilmenite from Humma lean grade beach placer deposit

Microwave heating is an eco-friendly and novel technique for sintering and heating minerals and materials as it has several advantages in terms of phase transformation, energy efficiency, enhancing speed, process simplicity, improved properties. Such heating provides the composite materials to absorb electromagnetic energy volumetrically and transform into heat and produces larger densities as compared to conventional heating. This study focuses on two main objectives: the recovery of ilmenite through a strategic combination of mineral processing equipment, including a spiral concentrator, followed by magnetic and electrostatic separation, and the enhancement of ilmenite concentrate using microwave heat energy on a cleaner magnetic product, followed by electrostatic separation. Continuous magnetic separation results indicate that among the dry high-intensity belt magnetic separator, box mag wet high-intensity magnetic separator and dry rare earth drum magnetic separators, the rare earth magnetic separator yielded the highest quality product. The application of microwave heat energy before the rare earth drum magnetic separator at 1.4 T, followed by high-tension separation, produced the best grade of ilmenite. The magnetic product obtained after microwave treatment contained 98.6% ilmenite, which was further upgraded to a 99.6% ilmenite concentrate through high-tension separation. Therefore, it is recommended that an effective combination of gravity separation, microwave heat energy, rare earth drum dry magnetic separation and high-tension separation be employed to achieve the highest grade of ilmenite concentrate.

Effects of Microwave Treatment on Alkyd-Varnished Wood Exposed to Outdoor Conditions

In this study, it was planned to investigate the effects of microwave irradiation (MW) prior to varnish applications on the pine wood samples, which are subjected to three months of outdoor exposure. The samples of 180W15s, 270W15s, 360W5s, and 360W15s showed lower water sorption properties than the control, while the rest of the samples showed higher sorption properties than the control sample. The lowest water sorption value was 12.50% (-3.85% lower than the control). It was found that post-microwave treated samples provide a 1–3 degree increases in resistance against selected cold liquids of distilled water, fruit juice, milk and coke under similar conditions. After three months of outdoor exposure of the samples, the surface scratch resistance of the samples was found to be 1 to 4 degrees softer than the control sample (HB to 3B pencil hardness properties). However, the cross-cut properties of the samples showed almost similar level of adhesion properties, mostly between 2 and 3 (control sample: 3), which was assumed to be not notable different from control, regardless of treatment conditions. It was found to have various discoloration properties of the samples which subjected to weathering procedure of post-microwave treated and alkyd-varnish aplied samples. But the larger-sized samples (A-type) have a higher and wider range for b* (yellowness) and a* (redness) values, while smaller-sized samples (a-type) showed a wider range and higher brightness (L*) properties. Moreover, A-type samples had higher total color difference values than a-types at similar treatment conditions. It is important to note that all measured samples show an ΔE >1.0 (metric) value, which means the discoloration after three months of outdoor exposure could be realizable when carefully examined by the human eye. The results clearly indicated that the post-microwave radiation before alkyd-varnish application on pine wood samples were some level influences regarding the selected properties. The resistance of selected household cold liquids and surface cross-cut properties were prominent for some samples. In spite of wide properties measured, no any clear trend was found between MW radiation and selected properties.

Optimization of microwave parameters to enhance phytochemicals, antioxidants and metabolite profile of de-oiled rice bran

The current study explores the effects of microwave treatment at varying wattage and durations on the phytoconstituents, antioxidant status, anti-nutritional factors (ANFs), and metabolite profiles of de-oiled rice bran. The total phenolics and flavonoids showed both increases and decreases depending on specific microwave parameters, while flavonol content consistently increased across all treated groups compared to the control. The DPPH and ABTS free radical scavenging activity, total antioxidant capacity, FRAP, CUPRAC, metal chelating activity, and ascorbic acid content were enhanced in most of the microwaved samples; however, longer microwave exposure at higher wattage led to their reduction. A treatment-specific decrease in ANFs, including condensed tannins, oxalates, and phytates, was observed. HRMS-based untargeted metabolomics identified a diverse range of primary and secondary metabolites, which clustered in a group-specific manner, indicating notable group-wise metabolite variations. Analysis of discriminating metabolites revealed no significant differences in the overall levels of phenolics, flavonoids, vitamins and cofactors, sugars, amino acids, terpenoids, fatty acids, and their derivatives among the treated groups compared to the control; however, several individual metabolites within these metabolite classes differed significantly. These findings suggest that optimized microwaving of de-oiled rice bran can enhance phytochemicals and antioxidants while improving the metabolite profile.

Influence of microwave processing on nutritional, anti-nutritional, antioxidant and sensory characteristics of kachnar powder and supplemented flatbreads

This study examines the impact of microwave processing on Kachnar (Bauhinia variegata) powder and its application in flatbreads. Microwave treatment reduced anti-nutrient levels of alkaloids, phytates, tannins, and saponins by 83–90 %, enhancing safety. Incorporation of microwaved kachnar powder (MwKP) into flatbreads at 2.5–10 % replacement levels improved nutritional profiles, with increases in ash (0.4–0.9 g/100 g), dietary fiber (2–3 g/100 g), protein (8–9 g/100 g), and minerals such as Fe (3–4 mg/100 g), Zn (3.2–3.9 mg/100 g), Na (3–10 mg/100 g), K (378–388 mg/100 g), Ca (30–45 mg/100 g), and Mg (125–145 mg/100 g). Antioxidant activity also increased significantly (p < 0.05) as measured by DPPH, ABTS, FRAP, and total phenolic and flavonoid contents. Sensory evaluation showed a decline in acceptability for MwKP levels ≥7.5 %, though 5 % supplementation was well-received. The findings suggest that microwave processing is an effective method for reducing anti-nutrient content in Kachnar while improving its nutritional and antioxidant properties, making it a viable ingredient for enhancing baked goods.

Microwave-induced alterations in the structure of coals at different metamorphic stages

Despite the global trend toward decarbonization, coal continues to play a significant role in energy production, as current renewable energy sources cannot fully meet the increasing global energy demand. The main objective of decarbonization is to reduce greenhouse gas emissions, especially carbon dioxide. Enhancing coal usage efficiency can help decrease these emissions. Electromagnetic activation of bituminous coal is already employed for dehydration, ash removal, desulfurization, and improving the grinding process of raw coal. This research aims to study the specifics of coal electromagnetic activation using microwave radiation and its effects on the physical and chemical processes occurring in coals at different metamorphic stages. The results suggest that this electromagnetic treatment leads to the destruction of hydroxyl groups and the formation of free hydrogen. Coals at higher metamorphic stages heat up faster due to their higher structural density. Coals at lower metamorphic stages take longer to heat up and require more processing time to be effective, while lower power levels are necessary to avoid mechanical breakdown. Activation time and coal particle size are significant factors; their optimal combination provides the maximum effect. These findings contribute to optimizing microwave treatment parameters for different coal types, potentially enhancing coal utilization efficiency and reducing environmental impact.

Flour Treatments Affect Gluten Protein Extractability, Secondary Structure, and Antibody Reactivity

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.

Remarkable improvement in the NOx storage ability of Pd/SSZ-13 zeolite PNA via a facile pretreatment strategy

A facile strategy was employed to pretreat Pd/SSZ-13 zeolite obtained via the initial-impregnated method under a microwave field, aiming to greatly enhancing the NOx storage-release ability. By investigating the effect of microwave treatment parameters (power, atmosphere and time) on the improvement of PNA performance, the optimal conditions were determined (175 W, 10 % O2/N2, 15 min). Under these conditions, the Pd/SSZ-13 exhibited an enhanced NOx adsorption and desorption amount to 2.60 and 2.38 times, respectively, compared to the untreated sample after three cycles of NO-TPD. Deeper insights into the variations in Pd/SSZ-13 properties induced by the microwave radiation were clarified through a series of characterizations. The micropore surface area of Pd/SSZ-13 zeolite activated by microwave increased by 3.91 %, and the micropore volume also improved by 3.85 %, which might facilitate the adhesion of more active Pd species to the materials surface, and aid in the dispersion of PdOx clusters into the zeolite channels. After microwave activation, the average particle size of Pd decreased from 10.09 nm to 7.08 nm. Particularly, the content of Pd(II) species such as Pd2+, [Pd(OH)]+ and PdO as active NOx adsorption sites enhanced from 66.68 % to 68.93 %. Additionally, the microwave treatment not only increased the number of Lewis and Brønsted acid sites, but also strengthened the interaction between NOx molecules and the zeolite skeleton. The above reasons collectively promoted the NOx storage-release properties of Pd/SSZ-13 zeolite, showing that the microwave pretreatment is a highly efficient strategy for improving the performance of PNA materials.

Modulation of textural properties in microwave treated gluten-free quinoa sponge cake by alkaline amino acids

Lysine (Lys) and Arginine (Arg) (0.6%) was added to the quinoa flour to improve the textural quality and physical properties of gluten-free sponge cake treated with different heating methods. The gluten-free sponge cake fortified Lys and Arg increased cell density and surface area fraction, compared to water bath (WB) treatment, with the microwave (MW) treatment further enhancing these effects. Furthermore, MW combined Lys treatment showed the best texture characteristics of sponge cake. The water distribution determined by 1H NMR presented that water molecules are bound by the protein network structure. FTIR spectrum proved MW combined with Lys promoted the transition from disordered structure to ordered structure of protein in quinoa sponge cake, which enhanced the expansion of protein molecules and the exposure of hydrophobic regions, thus promoting protein aggregation. SDS-PAGE revealed when alkaline amino acids were present, they can regulate the ordered aggregation of protein molecules under MW alternating electric field, leading to enhanced intermolecular interactions. Finally, microstructure evaluations by SEM demonstrated MW combined with alkaline amino acids formed a stable three-dimensional gel network structure, thus improving the quality of gluten-free quinoa sponge cake. Therefore, the study findings pointed to the feasibility of using MW to improve the physical and textual quality of quinoa gluten-free food.

Effect of microwave energy combined with hot air on the functional properties and antioxidant activity and pasting properties of Samh (Mesembryanthemum forsskalei Hochst) seeds

The study aimed to investigate the effect of microwave heating combined with hot air (70 °C) at different application times (0, 90 &180 s,) on the colour, digestible a soluble protein, functional and pasting properties, antioxidant capacity of Samh seeds (8, 12 & 16 % moisture content). The results indicated that microwave heating caused a significant change in Samh seed's colour and enhanced the protein solubility of the seeds, and the functional properties and viscosities of the Samh seeds. Moreover, the results showed that the moisture content of the Samh seeds and application time significantly impact the seeds' quality parameters. However, the partial least square (PLS) model validated that the microwave treatments of the samh seed with (16 %, 180 s) were treated with microwave energy combined with hot air circulation Accordingly, microwaves may offer the potential of being an effective emerging technology for improving the quality and functional characteristics of Samh seeds.