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The pursuit of energy-efficient and uniform processing drives ongoing research in microwave-assisted freeze drying (MWFD). While microwave application is acknowledged for its potential to reduce energy consumption of freeze drying applications, it introduces new challenges to gentle processing, particularly in achieving uniformity of processing due to the inherent uneven microwave field distribution in the drying chamber. This study investigates the impact of maximum drying temperature (Tmax) and microwave power input on energy consumption and uniformity in temperature-controlled MWFD. Experimental results reveal that shorter equilibration times associated with higher Tmax significantly amplify the inhomogeneity of temperature distribution. Further, higher Tmax was associated with a significant reduction in total energy demand of MWFD. Despite noticeable trends, microwave power input did not yield statistically significant differences in energy consumption or uniformity. The limited range of explored values, combined with the temperature-controlled nature of the process, may have rendered a potential influence of microwave power input negligible. This research elucidates the extent of inhomogeneity in MWFD, with implications for achieving uniform, gentle drying. It highlights the critical role of temperature control in MWFD. The study contributes to advancing the understanding of optimal processing in temperature-controlled MWFD. [ABSTRACT FROM AUTHOR]

This study investigated the combination of ultrasound pretreatment with microwave drying in food production, focusing on its impact on longan seeds. The study explored how ultrasound pretreatment and different microwave power levels affect drying kinetics, thermodynamic characteristics, and phytochemical properties during extraction. The results indicated that ultrasound pretreatment significantly boosts the drying rate by an average of 25% and reduces drying time by an average of 41.3%, while enhancing the phytochemical content of longan seeds, with increases of up to 35% for total phenolic content (TPC), 47% for total flavonoid content (TFC), and 42% for DPPH radical scavenging activity. Mathematical models accurately described the drying process and extraction kinetics, with the modified Henderson and Pabis model and the two-term exponential model being particularly effective. Furthermore, the study observed changes in entropy, enthalpy, and Gibbs' energy with varying microwave power levels and ultrasound treatment. This research demonstrated the potential of ultrasound pretreatment combined with microwave drying to improve the efficiency and phytochemical quality of longan seeds in food processing applications. [ABSTRACT FROM AUTHOR]

In this study, ginger was dried using the microwave infrared cooperative vibrating drying (MICVD) technique. Drying kinetics, moisture evolution, cell morphology and sample structure change, mechanical properties, and physicochemical properties of the sample during drying were investigated. The ginger dried at the microwave power of 0.4 W/g and infrared temperature of 50 °C (M0.4I50) exhibited the highest water diffusion rate. Significant moisture evolution in the sample was observed during the drying. The free water in the sample was removed rapidly, the immobilized water increased in the early drying stage and then decreased, and the bound water increased slowly throughout the drying. Removing moisture caused cell collapse in the ginger and the formation of moisture microchannels and pores. These structural changes resulted in increased fractal dimension, porosity, and volume shrinkage in the final dried product. Moisture evolution also significantly affected the rheological behavior of the ginger and its color profile. The correlation analysis result suggested that the key quality attributes of ginger, such as fractal dimension, porosity, color, volume shrinkage ratio, and rheological characteristic, were significantly correlated with moisture content and evolution. Moreover, backpropagation in the artificial neural network (BP-ANN) model was proved effective in predicting these key quality attributes based on its moisture content parameters. This study aimed to interpret the moisture evolution of ginger during MICVD drying and provide insight to future researchers on the development and application of this novel drying technique. [ABSTRACT FROM AUTHOR]

This study evaluated the impacts of various drying techniques—hot-air drying (HD), microwave rolling-bed drying (MRD), hot-air microwave rolling-bed drying (HMRD), microwave vacuum rolling-bed drying (MVRD), and vacuum freeze drying (VFD)—on the drying efficiency, physicochemical qualities, and flavor profile of Pleurotus eryngii. The Page and Midilli models effectively predicted the drying kinetics. MRD and HMRD notably reduced drying time by 52.67 and 65.65%, respectively, compared to HD. MVRD and VFD were superior in preserving nutritional quality, achieving higher rehydration capacity, nutrient retention, and antioxidant capacity. MVRD, in particular, demonstrated the shortest drying time (116.67 min), minimal color change, and a crispy texture, attributed to its significant porosity (84.32%). In addition, MVRD-treated products were rich in flavor with higher concentrations of alcohols, aldehyde compounds, and monosodium glutamate–like taste. These findings suggest MVRD as an advantageous method for producing high-quality dried P. eryngii products, balancing efficiency with sensory and nutritional integrity. [ABSTRACT FROM AUTHOR]

The future food industry is facing urgent challenges that need to be addressed, mainly providing sufficient quantity and quality of food to meet the growing population, reducing environmental pollution, improving production and processing conditions to adapt to climate change, protecting biodiversity, and improving food resource utilization. The global per-capita protein demand and consumption continue to grow, making it difficult for traditional protein supply channels to provide sufficient quantity and quality of protein. Ensuring a high-quality protein supply is an important task for future food processing, and the development trend of future food processing is mainly reflected in sustainable development, health, globalization, energy conservation and emission reduction, nutrition, technology, intelligence, and automation. These factors make the development and application of alternative proteins of great practical significance. Alternative proteins are still in the development stage; the relevant research focuses on the flavor, nutrition, safety, and consumer acceptance of the products. Different drying processes need to adapt to different types and applications of alternative proteins, and the drying process will have a significant impact on the recovery rate, recovery quality, and amino acid composition of proteins. This article provides a brief and comprehensive review of the development background, significance, types, applications, challenges, and solutions of alternative proteins based on the classification criteria of animal and plant derived from the perspective of alternative proteins. Some new drying technologies that can be used for alternative proteins are also introduced, including spray drying (pre-treatment, post-treatment, and optimization of process parameters), vacuum microwave drying, and other combined drying technologies. [ABSTRACT FROM AUTHOR]

The main objective of the present work was to study the optimization of microwave drying of potatoes that have different flesh colors. The effects of independent variables of microwave power (300, 450, 600 W), slice thickness (2–4, 6 mm), and steam blanching time (2, 5, 8 min) on the color, total phenolic content (TPC), antioxidant activity, starch ratio, and total monomeric anthocyanin content (TMA) were investigated by using the Response Surface Methodology (RSM). Before drying, potato slices that had different thicknesses were blanched in steam at 90 °C for indicated times. Optimization was applied to improve bioactive compounds, starch ratio, and color. The optimum drying parameters were determined as 300 W, 6 mm, and 8 min for purple-fleshed potatoes, and 450 W, 6 mm, and 2 min for yellow-fleshed potatoes. This study is beneficial to the development of the processing of potatoes in the food industry and provides more insights into the application of microwave drying technology. [ABSTRACT FROM AUTHOR]

This paper was conducted to model the drying kinetics of Capparis spinosa buds using dragonfly swarm optimized nonlinear regression and to compare the impact of drying treatments on their quality. Experiments included hot-air convective drying (HACD) from 40 to 120 °C, vacuum drying (VD) at 40, 60, and 80 °C, microwave drying (MD) ranging from 200 to 1000 W. Out of 30 models tested, the drying kinetics fitted best with Jena Das model in both HACD and VD and modified Midilli for MD. The comparison between the drying treatments used indicated that when taking into account the quality of the dried caper, VD at 80 °C was the most effective, resulting in a high-quality caper with a well-preserved color (ΔE = 7.47), high bioactives (TPC = 30.18mgGAE/gDW and TFC = 10.27 mg QE/gDW) and radical scavenging abilities (DPPH = 0.249 and ABTS = 4.448 mg/mL) at the expense of long duration (6h) and high specific energy consumption (50.667 kWh/kg). On the other hand, when considering the drying behavior MD ranked best with samples dried at 1000 W showing high diffusivities 2.04e−8 m2s−1 low energy consumption (MER 0.1216 kg/h), and short drying times (12 mn). This research is critical in selecting better drying conditions for increased usage in the culinary, cosmetic, and pharmaceutical sectors. [ABSTRACT FROM AUTHOR]

The industrial waste from sesame paste production (sesame seeds coat) is a valuable source of dietary fiber that could be used as a functional food ingredient. However, its high water activity (~ 0.98) makes it susceptible to microbiological contamination and rapid spoilage. This study addresses this issue by proposing microwave drying of the wet sesame by-product to reduce its water activity, followed by incorporating the dried sesame biomass into halva formulation to create a value-added product. Response surface methodology (RSM) was used to optimize the amount of sesame biomass and emulsifier in the formulation and quadratic models were developed for ten responses (stability, whitening index, taste, smell, color, ease of cutting, mouthfeel, friability, oiliness, and overall acceptance). The optimization results suggested incorporating 1% dried sesame coat and 3% emulsifier per kilogram of sesame paste, based on the evaluation of emulsion stability, texture, color, and sensory properties. Compared to the negative control without any additives (sample 1), this optimal formulation (sample 8) improved emulsion stability from 1.44 to 0.55% and hardness from 5.65 N to 68.93 N. Compared to the positive control with only emulsifier (sample 3), the addition of dried sesame coat and emulsifier had no significant effect on sensory properties, while enhancing nutritional value by increasing fiber content. Therefore, we recommend determining the fiber content of halva as further analyses to ensure that our product truly deserves the label "halva enriched with sesame fibers." [ABSTRACT FROM AUTHOR]

The aim of this research is to examine the effects of drying purple basil leaves (Ocimum basilicum L.) under different drying conditions (freeze drying, sun‐drying, and convective drying [CD] at 45, 50, and 55°C and microwave drying at 350, 460, and 600 W) on color properties, total phenolic and anthocyanin content, antioxidant activities, and changes in the composition of volatile compounds and essential oils (EOs). Increasing the drying temperature and microwave power led to an improvement in the preservation of the total phenolic content of the samples by an average of 16.28% and 27.98%, respectively. Increasing the drying temperature resulted in lower anthocyanin content and antioxidant activity (AA); in contrast, increasing the microwave power resulted in higher anthocyanin content and AA when drying purple basil. The drying methods significantly changed the composition of volatiles and EOs, and microwave drying resulted in a different profile of volatiles and EO composition. The key volatile compounds in purple basil leaves were linalol (81.19–1176.09 µg/g dw), 1,8‐cineole (45.15–816.16 µg/g dw), and methyl cinnamate (13.20–637.65 µg/g dw). On the other hand, methyl cinnamate (11.68%–57.66%) and linalool (0.02%–20.39%) were the main volatile compounds of EOs in basil leaves. In conclusion, the following drying methods are suitable for the protection of phenolic and anthocyanin compounds and high performance of AA: freeze drying, sun‐drying, and CD at 45°C and microwave drying at 600 W. [ABSTRACT FROM AUTHOR]

A microwave-hot air belt dryer (MHABD) showed high specific energy consumption (SEC) due to its limited material processing capacity and extended drying time. Thus, this research presents the development and performance evaluation of an industrial microwave-hot air belt dryer (IMHABD) for drying Namdokmai Sithong mango slices. The IMHABD system, optimized using the COMSOL Multiphysics program, features a 0.9 m × 4.08 m × 0.5 m chamber with 36 magnetrons having a maximum microwave power of 28,800 W (each magnetron produces 800 W) at a frequency of 2,450 MHz. Two drying methods were studied, step-down microwave power drying (IMHABD-S) and constant microwave power drying (IMHABD-C). IMHABD-S, with a power range of 150–350 W combined with hot air at 65 °C, outperformed IMHABD-C, delivering enhanced drying rates, improved color attributes, and reduced shrinkage, along with decreased hardness and toughness values. All dried slices had a water activity lower than 0.6. An IMHABD-S operated at 350 W for 1.5 h showed the lowest SEC. Economic analysis revealed strong support for the IMHABD process, with a net present value (NPV) of 13,647 USD, an internal rate of return (IRR) of 15%, and a 4.95-year payback with a 10-year service life, highlighting its technical efficacy and economic viability for mango drying applications. [ABSTRACT FROM AUTHOR]

Zeolite honeycomb monoliths (ZHMs) as key adsorbents or catalysts are widely applied in industries, for which, however, the popularization is limited by its low production efficiency due to the long and careful drying process of the fragile ZHMs green body. Here we address this challenge by developing a microwave drying strategy coupled with convective air and steam. The individual microwave, microwave-air, and microwave-air-steam drying characteristics on the honeycomb and slab monoliths of 13X zeolite were systematically studied, and the drying quality-microwave power/air temperature/humidity relationship was correlated. The results showed that microwave achieves rapid dehydration of ZHMs, eliminating 29.94 % relative mass of water within only 660 s. However, the uncontrollable microwave adsorbing inhomogeneity and thermal accumulation over the hydrophilic ZHM resulted in overburning, cracking and deformation issues. Introducing convective air at room temperature eliminates overburning and cracking phenomena, and after coupled with 110 g/m3 steam, the irregular deformation of ZHMs was further mitigated (shrinkage rate reduced from 2.10 % to 1.11 %) with even increased drying efficiency by 4.47 %. The advantageous mechanism of microwave-air-steam coupling drying was revealed as the combined effect of the heat and mass transfer through the honeycomb hole enhanced by convective air and the heating and dehydration homogeneity improved by uniform microwave absorbing on surface-condensable steam. The efficacy of the optimized drying strategy was demonstrated by significantly shortened time for scale-up production of 1 m3 ZHMs from nearly 1 month to 2 days. This work affords new insights for improving production efficiency of high-quality ZHMs and presents microwave-air-steam drying process as a platform to advancing structured material preparation. [ABSTRACT FROM AUTHOR]

BACKGROUND RESULTS CONCLUSION The powderization of salted egg yolks can circumvent the gelatinization issues that occur during frozen storage. In this study, salted egg yolk powder (SEYP) was prepared using microwave‐assisted foam drying (MFD) technology.The results show that, compared to traditional microwave drying and hot‐air drying, the SEYP prepared by MFD exhibits a bright color and a loose structure, and shows significant improvements in emulsifying properties, lecithin retention rate and antioxidant activity (P < 0.05). The optimal microwave power for MFD of SEYP, established through principal component analysis, is 350 W, with no requirement for a cooking treatment of the salted egg yolks. Gas chromatography–mass spectrometry identified n‐butanol, hexanal, nonanal, ethyl acetate, d‐limonene and isopentanal as the primary volatile compounds in SEYP, contributing to its unique flavor profile. Furthermore, the SEYP prepared using MFD at 350 W also shows a reduction of 18.88% in the content of bitter‐tasting amino acids compared with microwave drying.In summary, MFD technology is a green and efficient drying method suitable for the preparation of flavor‐type SEYP. © 2024 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Zirconia has important application prospects in the field of ceramics. However, during a high-temperature heating process, pure zirconia will undergo martensite transformation, which seriously affects its service performance. Metal oxides, such as Y 2 O 3 –CeO 2 doping ZrO 2, effectively improve the toughness and fire resistance of the material. Thus, the drying of Y 2 O 3 –CeO 2 co-doped ZrO 2 powder is an essential step before practical application. The study employs contemporary microwave drying techniques. The results of the experiment show that the average microwave drying rate increases with an increase in mass, water content, and microwave heating power. When the initial mass was 30 g, the initial moisture content was 12 %, microwave power was 720 W, and the drying rate was the fastest. We used four dynamic models: Modified Page, Quadratic, Wang and Singh, and Page to fit the experiment data. The best model was Modified Page, which describes the kinetic process most accurately. Fick's second law describes how, in the drying process, when microwave power is 720 W, initial mass is 15 g and initial water content is 8 %, the effective diffusion coefficient is 5.25 × 10−16 m2/s. Fourier Transforms of the infrared spectrum of the samples before and after drying were analyzed, the intensity of the O–H absorption peak located at 3442.03 cm/s, and O–H–O absorption peak located at 1594.48 cm/s. Both decreased significantly after drying. To discuss the relationship between the microwave power and the diffusion coefficient, the activating energy of microwave heating was 32.01 W/g. The experimental results show high heating efficiency and selective heating of the microwave method. This study provides a theoretical basis and research data for microwave drying of Y 2 O 3 /CeO 2 co-doped ZrO 2 powder in industry. [ABSTRACT FROM AUTHOR]

Strobilanthes crispus, a medicinal herb, is recognised for its abundant phytochemicals, notably in its leaves, contributing to its high antioxidant activity. However, the crucial step of drying, aimed at extending shelf life, can impact the stability of these bioactive compounds. This study evaluates the impact of different drying methods, which include oven, microwave, freeze drying, and air drying, on the colour, phenolic and flavonoid content, and antioxidant activities of S. crispus leaves. The colour analysis of the fresh and dried leaves was assessed using the chromameter. Total phenolic content (TPC) and total flavonoid content (TFC) were determined using Folin-Ciocalteu’s and aluminium chloride colourimetric assays, respectively. Antioxidant capacities were analysed via ferric-reducing antioxidant power (FRAP) and a 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging assay. The results showed that microwave-dried S. crispus leaves exhibited minimal alterations in colour attributes L*, a*, and b*, closely resembling the fresh leaves (p > 0.05). Microwave drying significantly preserved TPC (145.42 ± 1.61 mg GAE/g), TFC (117.27 ± 5.10 mg QE/g), FRAP activity (258.92 ± 0.15 µg TE/g extract), and displayed the most potent DPPH scavenging half-maximal inhibitory concentration(7.58 ± 0.48 µg/ml) compared to other methods (p < 0.05). Notably, the DPPH scavenging potency surpassed that of the synthetic antioxidant butylated hydroxytoluene. In conclusion, microwave drying appeared to be an efficient method for preserving the colour and antioxidant properties of S. crispus leaves. It highlights its potential as a favourable drying technique for conserving bioactive compounds in medicinal plant materials, offering promising applications in the nutraceutical and pharmaceutical fields. [ABSTRACT FROM AUTHOR]

Seasonings like garlic, ginger, and scallion provide spicy and masking flavor or aroma in vegetables. However, the method or technique used for drying these spices can affect the flavor profile. Therefore, this review focuses on vegetable seasonings like ginger, garlic, and scallion, the characteristic flavor of fresh and dehydrated vegetable seasoning, and how drying methods (freeze‐drying [FD], convective hot air drying [HAD], infrared drying, microwave drying [MW]), and other recent dryers (swirling fluidized bed [SFB], pulsed‐vacuum dryer, relative humidity‐convective dryer, etc.) affect the flavor profile of the common vegetable seasonings. HAD increases α‐zingiberene, reduces gingerol, and forms β‐citral and citral in fresh ginger. FD increased sesquiterpenes, retained terpenoids, sulfides, and other volatiles in fresh ginger, and did not produce new volatile compounds (VOCs) in garlic. SFB drying better preserves 6‐gingerol than FD and HAD. MW increases trisulfides and cyclic sulfur compounds in garlic. In general, drying, especially thermal drying reduces the VOCs in fresh garlic, ginger, and scallion and causes the formation of new VOCs. [ABSTRACT FROM AUTHOR]

The study evaluated the combined effects of drying methods (air drying [AD], hot AD [HAD], microwave drying [MD], and freeze‐drying [FD]) and ultrasonication parameters (sonication temperature [STemp]: 40, 50, and 60°C) and heating time (STime: 60 and 120 min) on natural deep eutectic solvent (NADES) extraction of phytochemicals from Amaranthus hybridus stem. Increasing the STemp increased the extraction yield (ECY) of the phytochemicals for all drying methods but increase in the heating time reduced the ECY slightly. MD combined with 60°C ST showed the highest ECY (53%), whereas HAD combined with 40°C ST had the lowest ECY (18%). At 60 min heating time, increasing the ST from 40 to 50°C increased the total phenolic content (TPC) in the extract for most drying methods except MD, and a sonication time of 120 min showed a slightly higher TPC, especially for MD samples. At 60 min sonication, total flavonoid content (TFC, 800 mgQE/g) was highest for AD plus 50°C ST and lowest for AD combined with 60°C (100 mgQE/g), whereas for 120 min sonication, MD and AD with 50°C showed the highest TFC (690 mgQE/g). FD retained better some of the vitamins (thiamine, riboflavin, niacin) but MD retained better vitamin C. The antioxidant capacity was not so much different among the drying methods except for FD, which showed lower values. These results provide a theoretical basis for the synergistic applications of drying and ultrasonication during NADES extraction of phytochemicals from Amaranthus hybridus. [ABSTRACT FROM AUTHOR]

Studies were conducted focusing on the drying of chili pepper fruits (Capsicum annuum L.), cultivar Cyklon, using convective (AD), convective-microwave (AMD), vacuum (VD), and freeze-drying (FD) methods. The influence of the drying method and temperature on the kinetics of the process and selected quality attributes of the dried product were evaluated. It was demonstrated that the Midilli model best described the drying kinetics for all methods across the entire measurement range. FD and VD produced dried products with the highest brightness and the greatest value of the a* color parameter. The lowest b* color parameter was observed for the product dried using FD at 40 °C, while the highest b* value was noted for samples dried using AMD (100 W) at 60 °C. The highest carotenoid retention was achieved with the FD method at 40 °C, while the lowest carotenoid content was found in the product obtained using the AMD method (100 W) at 60 °C. The smallest losses of capsaicinoids were observed after FD drying at 40 °C, while the largest were found for AMD (100 W) at 60 °C. The analysis of chili pepper fruit extracts revealed the quantitative composition of 12 main phenolic compounds using the UHPLC-UV method. The highest polyphenol content was obtained with FD, while the lowest total polyphenol content was recorded after AD. Regardless of temperature, the total flavonoid content was highest in extracts from FD products, and the lowest flavonoid content was found after AMD at 100 W. For all drying methods analyzed, the total flavonoid content in the pepper extracts decreased with increasing temperature. [ABSTRACT FROM AUTHOR]

Centella asiatica L. (CA) has garnered substantial attention in both commercial and research domains due to its bioactive compounds, imparting notable functional properties such as antioxidant activity. However, for enhanced shelf life and suitability in food and pharmaceutical applications, proper drying is imperative before utilization. Thus, this study investigated the impact of pretreatments, specifically steam blanching (SB) and cold plasma–activated water (CPAW), on the drying kinetics and quality attributes of CA leaves during microwave drying (MWD). Five semi-empirical models were employed to fit the drying data, and the best-fitted model was determined using the Akaike information criterion (AIC). Subsequently, MWD was optimized through a face-centred central composite design, with microwave power and drying time as independent parameters. The Page and Logarithmic models exhibited the best fit to the drying data, as per AIC with R2 values ranging from 0.981 to 0.999 and RMSE values from 0.008 to 0.051. Notably, CPAW pretreatment exhibited a more pronounced effect on both drying kinetics and quality parameters compared to SB. Optimal drying conditions were identified as a microwave power of 540 W and a drying time of 6.99 min. This study concludes that microwave drying with CPAW pretreatment is a sustainable method for obtaining dried CA leaves with optimal nutritional qualities, making it relevant from an industrial perspective. [ABSTRACT FROM AUTHOR]

Bletilla striata is widely used as healthy food and herbal medicine for its hemostasis, anti-ulcer, promoting wound healing, antibacterial, anti-inflammatory, and immune regulatory functions. Drying methods affect the quality of herbal medicine, including appearance and more importantly the content of active components, which play a decisive role in the medical and tonic functions. In this study, hot air drying (HD), infrared drying (ID), microwave drying (MD), vacuum drying (VD), and freeze drying (FD) were used to evaluate the effect of drying methods on the quality of B. striata tubers. Significant effects of drying methods on the appearance, color, microstructure, water activity, water content, and active component content of B. striata tubers were observed. FD-treated samples retained the majority of the appearance, color, and microstructure, while samples processed with other methods exhibiting various deformation and discoloration. In addition, a significant decline in water content and water activity was detected in FD-treated samples, yet, the content of active components, such as B. striata polysaccharides, total polyphenols, and militarine, was relatively high. After comprehensive comparison, freeze-drying is proposed to be the most suitable method for B. striata drying, which is also recommendable for other tuber drying. [ABSTRACT FROM AUTHOR]

In this study, apricot samples were dried by using different drying methods (tray drying, microwave drying, and freeze drying). Moreover, different pretreatments (infrared, ultrasound, and treatment with dipping green tea extract) were also applied to the samples. The effect of process conditions on physical and chemical quality of dried apricot samples were investigated. It was aimed to come of age of these technologies as an alternative to conventional pretreatments. Among all drying techniques, the shortest processing time was achieved by microwave drying at 270 W. Midilli was found to be the best model that fits the moisture ratio values among 10 thin layer models. Freeze dried samples had the lowest water activity which ranged from 0.2260 to 0.4868 and rehydration capacity of dried samples were found to be between 2.40 and 3.09. Besides, it was found that the total phenolic content of dried apricots varied between 99.24 and 512.60 mg GAE/100 g dry matter. In addition, the maximum antioxidant activity values for microwave drying (270 W) were obtained in the green tea extract pretreated samples and calculated to be 1.85 ± 0.01 mg TE/g dry matter. NMR and SEM analysis were also applied to the samples. To sum up, it can be declared that microwave technology and green tea extract pretreatments were superior and had beneficial impacts on the end product's quality. [ABSTRACT FROM AUTHOR]

The study aims to investigate the impact of various drying techniques on the quality of sulfated polysaccharides (SP) extracted from Skipjack tuna (Katsuwonus pelamis) skin. Three drying methods, namely microwave drying (M‐KPP), freeze‐drying (F‐KPP), and hot air drying (HA‐KPP), are examined. The chemical and monosaccharide compositions of SP are significantly affected by the drying methods. The extraction yields for M‐KPP, F‐KPP, and HA‐KPP are 3.30%, 3.11%, and 2.50%, respectively (P < 0.05). Additionally, HA‐KPP, with 10.67% moisture content, exhibits the lowest moisture level among the dried samples (P < 0.05). Furthermore, the structural properties of SP remain consistent across different drying methods, as indicated by FTIR, XRD, and DSC analyses. F‐KPP demonstrates the highest antioxidant properties. The functional and antimicrobial activities of SP are significantly influenced by the drying technique, with hot air drying resulting in increased foaming capacity and microwave drying showing enhanced antimicrobial activity. In conclusion, the findings demonstrate that the functionality and bioactivity of SP from tuna skin are greatly influenced by the drying technique employed, suggesting that the selection of the optimal method should be tailored to the desired properties of the SPs and given careful consideration. [ABSTRACT FROM AUTHOR]

The mulberry fruit is edible and medicinal, and it is commonly referred to as the "best health product of the 21st century". The purpose of this study was to find out whether different drying methods affect the quality of mulberry fruits and the main nature of the volatile organic compounds (VOCs) they contain. This study used vacuum freeze-drying (VFD), vacuum drying (VD), sun drying (SD), hot-air drying (HAD), and microwave drying (MD) to treat fresh mulberry fruits. Gas-phase ion mobility spectrometry (GC-IMS) was used to detect and analyze the VOCs in mulberry fruit samples treated with the different drying methods. There were 47 VOCs detected, with aldehydes and alcohols dominating. The obtained data were subjected to principal component analysis (PCA), cluster analysis (CA), nearest neighbor fingerprint analysis, and partial least-squares regression analysis (PLS-DA). The conclusion was drawn that fresh mulberry fruits contain abundant VOCs, and mulberry fruits after VD contain many aldehydes; thus, VD promoted the synthesis of phellandrene and other compounds widely used in the preparation of cosmetics such as perfume and soap. HAD promoted the synthesis of esters commonly used in the preparation of fruit flavor and wine essence. The higher (E)-2-heptenal content with SD was conducive to the Maillard reaction. MD promoted the synthesis of heptanal and valeraldehyde with aroma characteristics such as fatty, green, fruity, grassy, and floral. According to the VIP results, VOCs (E)-2-heptenal, pentanal D, cyclohexanone, and 2-hexanone D influenced the VOCs in most of the mulberry fruit samples. The findings of this study provide an important reference for drying mulberry fruits, which, in turn, will help to ensure the safety and effectiveness of processed mulberry fruit products. [ABSTRACT FROM AUTHOR]

Ficus carica Linn leaves represent a rich source of various bioactive compounds providing various features. Drying was inevitably preferred as a hopeful technique aiming to provide the availability of leaves and effective utilization of them in various fields. In the present study, the effects of microwave drying of dried Ficus carica L. leaves on optical, rehydration and bioactivity parameters were examined. The leaves were dried using a variety of microwave output power levels (180–900 W) with sample amounts (20–100 g). The effect of microwave drying on the optical properties of leaves was discussed based on the colour parameters (L, a, b) and total colour change (∆E). The final value of L, a and b and colour change (∆E) were respectively found as 37.60 ± 0.49, − 10.07 ± 0.33, 16.08 ± 0.18 and 10.19 ± 0.062 for constant sample amount (20 g) at 900 W microwave output power level. On the other hand, the final value of L, a, b and colour change (∆E) were respectively found as 33.70 ± 2.25, − 8.79 ± 0.87, 13.99 ± 0.53 and 6.52 ± 0.99 for the 100g sample amount at 360 W microwave output power level. The bioactive compounds of the leaves were handled in terms of total phenolic content (TPC) and scavenging activity (IC50) corresponding to the capability to scavenge 50% of radicals. The results explored that the TPC of fresh leaves, 46.77 ± 0.39 (mg GAE/g DE), increased to 53.15 ± 1.25 (mg GAE/g DE) by increasing microwave power intensity. Thereby, the IC50 value of fresh leaves, 768.77 ± 1.58 (μg/mL), decreased to 577.14 ± 1.85 (μg/mL). The kinetics and empirical models were successfully fitted to the experimental data obtained for microwave power intensity applied. Finally, it was concluded that the microwave technique could be safely applied for drying Ficus carica Linn leaves without detecting any undesirable change in the quality parameters monitored such as colour, rehydration and bioactive compounds. [ABSTRACT FROM AUTHOR]

The aim of the study is to enrich pasta with cornelian cherry powder, a product with high bioactive contents. In this way, it was aimed to obtain a new product that is more nutritionally advanced and can contribute to the country's economy. In this study, cornelian cherry with high bioactive content and an attractive color advantage was used for the enrichment of the pasta formulation. In addition, the pasta production procedure was revised by applying microwave technology for drying. Cornelian cherry powder:dough ratio, dough thickness, and microwave power were optimized with response surface methodology. Total phenolic content, antioxidant activity, color, and water‐holding capacity were determined as responses. Optimum conditions were found as 4.53% for powder:dough ratio, 0.1 cm for dough thickness, and 270 W for microwave power. According to optimization results, it was detected that the cornelian cherry powder:dough ratio affected the total phenolic content and antioxidant activity, and microwave power was found to be effective only on antioxidant activity. For optimum conditions, the total phenolic content and antioxidant activity were found as 1.29 GAE/g and 0.5 mg TE/g, respectively. The characterization analysis showed that the microwave–dried sample shrank less than those dried with the conventional method. In Fourier transform infrared spectroscopy (FTIR) results, it was determined that the amount of carbohydrates in the samples obtained under optimum conditions was lower than that of control. It has been observed that the application of microwave technology for drying pasta enriched with cornelian cherry powder had positive effects on the quality of the final product. [ABSTRACT FROM AUTHOR]

Microwave dehydration technology has been widely used in coal processing methods due to its unique advantages. Adding additives with high dielectric loss to coal can enhance the microwave absorption capacity of coal, so as to effectively improve the dehydration process. In order to understand the change and distribution of multi-fields in the microwave drying process of lignite under the action of different additives, verify the experiment and reduce the cost and number of experiments, this paper established a multi-field coupling model of electromagnetic field and heat and mass transfer of multiphase porous media based on COMSOL Multiphysics, so as to simulate the microwave drying process of lignite. The results show that the distribution areas of electromagnetic field, temperature field, and vapor in coal are basically the same, while the distribution of liquid water is just the opposite. With the enhancement of additive promotion effect, the parts with strong electromagnetic field strength increase, the hot spots of temperature field increase, the maximum temperature, and minimum temperature increase, and the water content in coal samples decreases. The promotion effect of additives on the microwave dehydration process of lignite is consistent with the experiment. [ABSTRACT FROM AUTHOR]

Freeze drying (FD) is a technique used to preserve the bioactive content and flavor of samples. Foods with a short shelf life due to nature have been preserved via FD in recent years. The success of the drying technique is thanks to the high retention ability of the bioactive compounds and the flavor of the sample. However, the high cost and energy consumption of FD limit its usage in several fields. Freezing, primary drying, and secondary drying, which take place in the same device, are the stages of FD. In addition, several parameters, including pretreatment, size, temperature, sample species, time, and pressure, affect the FD process. These parameters are controlled to increase the effectiveness of FD on the samples. Moreover, FD has been compared with other drying techniques including hot air drying, microwave drying, vacuum drying, and solar drying to determine its protective capability. It has also been applied to the valorization of waste products, which is a common problem worldwide. For valorization, microencapsulation and powder production have been achieved using FD. In recent years, studies on the effects and use of FD on various materials increased, providing new aspects for the future of science and food industry. [ABSTRACT FROM AUTHOR]

The global consumption of dried mushrooms has increased worldwide because of their rich nutritional value and culinary versatility. Dehydration methods such as sun drying, hot air drying, freeze drying, and microwave drying are employed to prolong the shelf life of a food product. These methods can also affect the food product's nutritional value and the final product's microbial profile. Each technique affects the retention of essential nutrients like vitamins, minerals, and bioactive compounds differently. Additionally, these techniques vary in their effectiveness at reducing microbial load, impacting the dried mushrooms' safety and shelf life. This review addresses the gap in understanding how different dehydration methods influence dried mushrooms' nutritional quality and microbial safety, which is crucial for optimizing their processing and consumption. It targets researchers, food processors, and consumers seeking to improve the quality and safety of dried mushrooms. This review comprehensively examines the impact of major dehydration techniques, including sun drying, hot air drying, microwave drying, and freeze drying, on the nutritional and microbial profiles of dried mushrooms. Each method is evaluated for its effectiveness in preserving essential nutrients and reducing microbial load. Current research indicates that freeze drying is particularly effective in preserving nutritional quality, while hot air and microwave drying significantly reduce microbial load. However, more well-designed studies are needed to fully understand the implications of these methods for safety and nutritional benefits. These findings are valuable for optimizing dehydration methods for high-quality dried mushrooms that are suited for culinary and medicinal use. [ABSTRACT FROM AUTHOR]

The goal of this study was to find a way to shorten wood drying time by using microwave and combined infrared + microwave drying methods and to analyze color and gloss changes. Wood samples prepared in three groups with dimensions of 20 x 20 x 30 mm were used in moisture tests and 75 x 5 x 150 mm were used in color change and gloss measurements, obtained from Red pine (Pinus brutia) and Eastern spruce (Picea orientalis) woods. The samples were oven dried, dried by microwave, or dried by infrared + microwave drying method. The wood samples all reached the target moisture. Their weight and volume were calculated in accordance with the principles of TS ISO 13061-1. Color change values were determined before and after drying with a portable color reader (Konica Minolta CR-10) device, and gloss measurements were taken with the Gardner brand gloss meter. By microwave drying for 15 min, 4% moisture content was reached in the wood samples, so both time and energy were saved. The moisture content values decreased compared to the whole drying methods. Most color change was observed in the drying methods using infrared for both red pine and eastern spruce. [ABSTRACT FROM AUTHOR]

Solid desiccants have been widely used in dehumidification systems, but the regeneration of desiccants is significant for the economy and environment protection. The regeneration performance of several typical solid desiccants was examined in a microwave combined hot air lab-scale setup. The shortest time required for desiccants happened in the combined heating. Among eight desiccants, zeolite in the combined drying took the shortest time to be regenerated. Activated alumina was the most difficult to be regenerated, and it in the hot air drying had the highest absorption capacity, while 3A (1.6–2.5) zeolite in the microwave and combined heating had the highest absorption capacity. Silica gels in all heating modes had the minimum absorption capacity. At low power levels (100-300W), the regeneration performance of the silica gels was prompted by the multi-magnetron radiation modes with the top one. The temperature distribution uniformity in silica gel was lifted with the assisted hot air drying. The multi-magnetron could ameliorate the microwave heating uniformity. The combined drying not only could lift the heating uniformity of the microwave, but also lowered the energy consumption by the traditional hot air drying alone. This study can provide basic data for the design and improvement of the desiccant rotors. [ABSTRACT FROM AUTHOR]

The volatile oils of Satureja species are rich in thymol and carvacrol, phenolic bioactive compounds with unique biological properties. Drying is one of the most critical post-harvest treatments that can influence the biosynthesis of the phytochemicals and the microbial quality of the plant. This study aimed to investigate the effect of different drying methods (shade, sun, oven (temperature of 40, 50 and 60°C), microwave (power of 100, 200, 300, 400, 500 and 600 W), and freeze-drying) on the quantity and quality of essential oil (EO) and the control of microbial contamination of S. spicigera flowering shoots. The results showed that shade drying produced the highest amount of EO (1.35%). The maximum values of thymol (60.64%) and carvacrol (42.4%) were determined after drying in a microwave at 400 W and oven at 40°C, respectively. Thymol and carvacrol are selectively biosynthesized with the highest conversion rate of the precursor p-cymene under microwave irradiation at 400 W and oven heating at 40°C, respectively. Based on the evaluation of microbial contamination of the dried plant, the highest microbial control was achieved by freeze drying, with minimal contamination of Enterobacteriaceae (1.7%), Staphylococcus aureus (3.4%), Salmonella sp. (1.64%), moulds and yeasts (12.5%). [ABSTRACT FROM AUTHOR]

Summary: Three freeze–thaw (FT) pre‐treatments using different freezing methods that freezing at −80 °C (FT‐80), freezing at −25 °C (FT‐25) and vacuum freezing (VFT) were used for carrot slices, the effects and mechanisms of FT pre‐treatment on the drying characteristics and product quality of carrots during microwave freeze drying (MFD) were studied. The results showed that FT pre‐treatment under different freezing methods affected the water state of carrots, resulting in varying degrees of moisture loss and shortening drying time by 14.3% to 42.8%. VFT treatment caused the greatest water loss (35.33%) during FT and significantly increased the effective moisture diffusivity in the MFD process. FT treatments did not cause any significant degradation in the colour of the carrots. The VFT and FT‐80 treatments resulted in an elevated rehydration ratio, increased crispiness of MFD carrots and products with a porous microstructure and higher porosity. In contrast, the FT‐25 treatment led to a decrease in porosity due to destructive damage to the carrot cell structure. However, this damage favoured the extractability of carotenoids, resulting in a higher carotenoid content than the other treatments. This study provides a theoretical foundation for the practical implementation of FT pre‐treatment using various freezing methods on fresh foods prior to drying. It is recommended to employ VFT pre‐treatment before MFD due to its efficiency and effectiveness. [ABSTRACT FROM AUTHOR]

The Mediterranean evergreen carob tree (Ceratonia siliqua L.) produces pods, that may be edible and even therapeutic. The purpose of this study was to determine how ethanolic extracts of carob pods from Morocco, prepared with ultrasonic assistance were affected by microwave (525 °C for 2.5 min), hot air (65 °C for 16 h), and spray drying (input and output air temperatures 180 and 90 °C, respectively, feed flow rate 2.5 mL/min and 5 bars, respectively), in terms of their physicochemical composition and biological activity. Colorimetric techniques were utilized to ascertain the phytochemical contents of pod extracts, whereas standardized in vitro methodologies were employed to quantify the antioxidant and antimicrobial activities. Physicochemical analysis showed that microwaved powders of carob pods presented significantly high (p < 0.05) values of L* (62.15±0.06) and b* (21.32±0.06), and lower values of a* (4.16±0.03), as compared to spray dried and hot air-dried powders. Significantly high (p < 0.05) amounts of ash (3.92±0.05 %), fat (1.48±0.02 %), fiber (7.45±0.12 %) and protein (2.65±0.06 %) were found in microwave dried powders, followed by spray dried and hot air dried. Significant difference in macro and micro minerals among three powders was also observed, as microwave dried powders were found to be significantly high (p < 0.05) in Mg, K, Ca, Fe, Zn and Mn, followed by spray dried powders, whereas hot air-dried powders presented lowest values. Similarly, spectrophotometric analysis of phytochemicals revealed that ultrasonic assisted ethanolic extracts of microwave dried powders were found to be highest in total phenolics, flavonoids and carotenoids, with values 69.18±0.15 mg GAE/g, 34.88±0.08 mg QE/g and 24.05±0.15 mg g-1, respectively. In vitro antioxidant and antimicrobial analysis also showed a similar trend as, extracts of microwave dried powders exhibited significantly high (p < 0.05) antioxidant and antimicrobial activities, followed by spray dried and hot air-dried. As compared to hot air and spray drying, the microwave drying and ultrasonic assisted extraction using 70 % ethanol as solvent could be employed on carob pods, to obtain powders and extracts, respectively, with minimum degradation of physicochemical characteristics, and maximum retention of nutritional, bioactive and antioxidant contents. In recent years, Morocco has become more and more dependent on the use of carob fruit and its powders. Nonetheless, very rare is known about the composition and carob pod quality of those grown in Mediterranean nations. The current study presents a comparison of the effects of three distinct commercial drying methods on the composition and physical characteristics of flour made from carob pods. The study's findings can also be used to evaluate how well information is composed, processed, and preserved for use in future research and commercial applications. [Display omitted] • Comparative analysis of hot air, spray, and microwave drying of carob pods powder. • Microwave drying, provides optimum physicochemical retention of carob powder. • Phytochemical of carob powder are highly affected under different drying conditions. • Sonicated extract of microwave dried powder provided highest amount of bioactives. • These showed significantly high in vitro antioxidant and antimicrobial activities. [ABSTRACT FROM AUTHOR]

In this study, a new microwave infrared hot air rolling bed dryer (MIHRBD) was developed and computational fluid dynamics (CFD) techniques were introduced into the design process of the integrated drying system. The structure of the air distribution device was optimised to improve the airflow uniformity over the curved surface of the rolling bed in the microwave-hot air drying combined equipment. The research findings reveal that, across eleven models, the outlet airflow velocity stabilises once the number of mesh elements reaches 5 million, achieving significant computational accuracy at that point. Optimizing components like the uniform air distribution pipe, turbulence plates, and wind deflectors significantly enhanced airflow distribution uniformity by 52.1%. The best airflow and temperature distribution uniformity on the rolling bed surface was achieved when the inlet airflow velocity ranged from 1 to 3 m s−1, with minimum V d , U v and temperature non-uniformity coefficients of 0.007 m s−1, 7.2% and 0.2%, respectively. Validation tests on the MIHRBD pilot equipment showed that after optimizing the uniform air distribution device, the minimum temperature difference on the pleurotus eryngii surface was 3.1 °C. This confirmed the feasibility of the computational fluid dynamics method. Introducing hot air significantly enhanced pleurotus eryngii 's drying uniformity, with the Page model effectively predicting the MIHRBD drying process. This study provides technical support for future developments in this field of equipment manufacturing and drying process analysis. • A new microwave infrared hot air rolling bed dryer (MIHRBD) was developed. • Design of MIHRBD with advanced CFD for enhanced airflow uniformity. • Optimised uniform air distribution design increases airflow uniformity by 52.1%. • Colour quality of dried materials improved by optimised MIHRBD process. [ABSTRACT FROM AUTHOR]

Copyright of Modern Food Science & Technology is the property of Editorial Office of Modern Food Science & Technology 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.)

Apple and ginger mixed pomace is a by-product that can be valorized by drying. In this study, mixed pomace was subjected to hot-air drying (HAD) at 45, 62, and 70 °C and stepwise at 45 °C followed by at 62 °C or the reverse, at 62 °C followed by at 45 °C (2.5 mm layer), and microwave drying (MWD) at 100, 180, and 300 W (2.5 mm and 1.5 mm layers) and stepwise at 100 W followed by at 300 W (2.5 mm layer). The results show that the Crank model well fitted the HAD kinetics, with a water effective diffusivity (Deff) of 2.28 ± 0.06 × 10−10–4.83 ± 0.16 × 10−10 m2/s and energy of activation of 23.9 kJ/mol. The step approach of drying at 45 °C followed by at 62 °C resulted in a higher Deff than the reverse approach (drying at 62 °C followed by at 45 °C). The Midilli et al. model presented a good fit for the MWD kinetics. The drying time was calculated using these models to achieve 12% moisture content in the pomace and found to be 125.0 ± 9.2–439.5 ± 118.2 min for HAD, and 11.1 ± 0.2–61.5 ± 6.0 min for MWD. The specific energy required was 410.78 ± 6.30–763.79 ± 205.4 kWh/kg and 1.32 ± 0.01–2.26 ± 0.05 kWh/kg, respectively. MWD at 180 W preserved the total phenolic content and the antioxidant activity (ABTS, DPPH) better than HAD at 62 °C. The former technology also preserved the pomace color well, with a low color difference, ΔE, of 7.39 ± 1.1. Therefore, MWD is more promising than HAD to dry apple and ginger pomace, reducing the environmental impact of the drying process due to its lower energy consumption, shorter drying time, and better quality. The dried product could be converted into apple and ginger pomace flour to be used as a novel food ingredient. [ABSTRACT FROM AUTHOR]

In this research, the objective was to optimize the drying process of Astragalus by investigating the effects of microwave vacuum drying parameters, including temperature (30, 35, 40, 45, and 50 °C) and slice thickness (2, 3, 4, 5, and 6 mm). In addition, utilizing COMSOL 6.0 finite element analysis software, we delved into the distribution of heat and moisture during the drying process. The results revealed that drying temperature played a significantly greater role than slice thickness in determining the drying dynamics. The thermal and mass transfer mechanism indicated that the whole drying process conforms to the microwave radiation mechanism and the basic principle of electromagnetic heating. In the case of low temperatures and thinner slice sizes, the more polysaccharide content was retained; The total phenol content peaked when the slice thickness was 5 mm; The increase of slice thickness was not conducive to the retention of total flavonoids content. The potent antioxidant capacity was detected at a temperature of 40 °C, with slice thickness having a negligible effect on this capacity; Low temperatures were beneficial for the preservation of active ingredients. Compared with the scanning electron microscope, the structure appeared more uniform at a temperature of 50 °C. Based on the analysis of the kinetic characteristics of microwave vacuum drying of Astragalus and the quality achieved under various drying conditions, the results of the study can provide valuable guidance for controlling the quality of microwave vacuum drying of Astragalus under different drying requirements. [ABSTRACT FROM AUTHOR]

The objective of the present research was to determine the nutrient utilization of full-fat black soldier fly larvae (Hermetia illucens; BSFL), which were processed by various drying methods, using in vitro procedures for pigs. Four sources of BSFL were prepared using various drying methods: (1) hot-air drying at 65 °C for 24 h; (2) microwave drying at 700 W for 5 min, three times; (3) freeze drying at −40 °C for 72 h; (4) infrared drying at medium infrared region (ranged from 2.0 to 6.0 μm) and at 95 °C for 12 min. In vitro ileal disappearance (IVID) of nutrients in the BSFL was measured using a procedure simulating the nutrient digestion and absorption in the stomach and small intestine of pigs. In vitro total tract disappearance (IVTTD) of nutrients in the BSFL was also measured using a procedure that simulated the total intestine of pigs. The contents of dry matter, ether extract, and crude protein in the dried-BSFL ranged from 94.6 to 96.8%, 49.2 to 52.8%, and 30.0 to 36.8%, respectively, on an as-is basis. Microwave drying resulted in a greater (p < 0.05) IVID of dry matter in BSFL, compared with the freeze drying or infrared drying method, which caused the least IVID of dry matter. Hot air-dried BSFL, microwave-dried BSFL, and freeze-dried BSFL had a greater (p < 0.05) IVID of crude protein and a greater (p < 0.05) IVTTD of dry matter and organic matter, compared with infrared-dried BSFL. In conclusion, the hot-air drying, microwave drying, and freeze drying of full-fat black soldier fly larvae resulted in fairly comparable and relatively high nutrient digestibility based on the present in vitro study for pigs. However, the infrared drying method impaired nutrient utilization of full-fat black soldier fly larvae for pigs. [ABSTRACT FROM AUTHOR]

This study examined the effects of hot air drying (HAD), infrared radiation drying (IRD), microwave vacuum drying (MVD), freeze drying (FD), and freeze drying combined with microwave vacuum drying (FD-MVD) on the drying kinetics, color, rehydration ratio, titratable acidity, and vitamin C content of small white apricots (Prunus armeniaca L.). Results showed drying times of 12.5 h (IRD), 14.1 h (FD), 16 h (HAD), 0.53 h (MVD), and 6.15 h (FD-MVD). FD-MVD significantly outperformed MVD, HAD, and IRD in color, vitamin C, titratable acidity, and rehydration, though was slightly inferior to FD. Microstructural analysis revealed that FD-MVD preserved the most uniform pore structure, better maintaining apricots' original appearance. In contrast, IRD and HAD caused severe surface shriveling, compromising quality. In conclusion, FD-MVD emerges as a promising drying method to enhance apricot quality and market competitiveness in food processing. [ABSTRACT FROM AUTHOR]

The article presents the results of studies of the process of accelerated drying performed by means of microwave radiation of ceramic moulds deposited on patterns made of foamed plastics used in the Ceramic Shell technology. The studies aimed at determining the microwave radiation parameters (power, downtime, and uninterrupted operation time) in order to obtain the maximally short drying times which do not cause pattern destruction. The analysis of results confirmed that an increase of the microwave radiation power shortens the drying time of the particular layers of the ceramic mould, however, at the same time, it excessively raises the temperature of the mould. With the microwave power over 1200 W, we can obtain the drying time of one layer at the level of about 30 min, and the temperature of the mould reaches the value of 70oC, which does not cause deformation or partial melting of the polystyrene pattern. From the point of view of production effectiveness, as a result of the application of microwave drying, the time of production of ceramic moulds was shortened from 7 days to 1 working day.

Y2O3–Al2O3–ZrO2 composite ceramic powders are an important structural and functional material. The agglomeration problem in the ceramic powder drying process must be resolved to prepare high-quality ceramic powder, and choosing the right drying techniques can significantly lessen ceramic powder agglomeration. Y2O3–Al2O3–ZrO2 ceramic powder was dried using microwave drying. The drying kinetics of the powders were examined with their initial mass, moisture content, and microwave power. As microwave power, beginning moisture content, and initial mass rose, the average drying rate also increased, according to the experimental data. To better characterize the microwave drying process, the drying data were fitted and analyzed using four thin-layer drying kinetic models, namely Quadratic Model, Modified Page, Wang and Singh, and Two-term exponential. The outcomes demonstrate the good fitting effect of the Modified Page model and the compliance of the fitting parameters with the law. The samples before and after drying were characterized by Fourier transform infrared spectroscopy. Calculating the diffusion coefficient by Fick's second law shows that the effective diffusion coefficient of Y2O3–Al2O3–ZrO2 composite ceramic powder is 5.6 × 10−11 m2/s when the initial moisture content is 5%, the microwave heating power is 560 W, and the initial mass is 25 g. The activation energy for microwave drying of Y2O3–Al2O3–ZrO2 ceramic powders was calculated to be 22.83 W/g according to the Arrhenius formula. This paper aims to provide a theoretical basis and rich experimental data for the study of microwave drying of Y2O3–Al2O3–ZrO2 composite ceramic powder.

TiO2–Y2O3–ZrO2 composite ceramics exhibit excellent abrasion resistance, corrosion resistance, and high-temperature resistance, making them vital structural-functional materials in ceramics and refractories. The key to preparing high-quality TiO2–Y2O3–ZrO2 ceramic powders lies in controlling the agglomeration rate, which can be optimized by choosing an appropriate drying method. This study utilized microwave drying techniques to dehydrate TiO2–Y2O3–ZrO2 ceramic powders. It was found that the average drying rate is proportional to initial masses, initial moisture contents and microwave heating powers. To describe the drying process, four models—the Quadratic, Wang and Singh, Modified Page, and Page—were employed. The best model for the drying process was the Modified Page model. The specimens were analyzed to assess the alterations in the samples pre and post-drying by scanning electron microscopy and Fourier transform infrared spectroscopy. The findings revealed that microwaves can hasten the drying process of TiO2–Y2O3–ZrO2 and enhance its spread. Utilizing Fick's second law, the effective diffusion coefficient was ascertained, showing an inverse proportionality to the sample mass, and a proportionality to the microwave heating power and initial moisture content. Using the Arrhenius exponential model, it was ascertained that the microwave drying process's activation energy stands at 13.81834 W/g. This paper demonstrates that microwave drying effectively achieves efficient drying and lays the theoretical and experimental groundwork for the microwave heating and drying of other powdered materials.

To improve the uniformity of microwave heating and enhance the quality of continuous microwave drying for raspberry pulp, a self-developed programmable logic controller (PLC) control system with pulsed microwave output was implemented. The central composite experimental design method was employed to analyze the effects of four experimental factors, namely microwave duty cycle, pulse period, air velocity and drying time on the average temperature, temperature dispersion value, moisture content, moisture content dispersion value, anthocyanin retention rate, and anthocyanin retention rate dispersion value of raspberry pulp. The optimal process for pulsed microwave drying of raspberry pulp was obtained. Compared with dried pulp quality and uniformity indexes from pulsed microwave drying, commonly used feedback temperature control microwave drying, intermittent microwave drying, and continuous microwave drying processes to develop a continuous microwave drying quality optimization control system for raspberry pulp. The results showed that the magnetron from pulsed microwave drying in the form of pulse output rectangular wave form power through the PLC control system. Turning on the magnetron intermittently was more effective than continuous microwave heating. Pulsed microwave drying of raspberry pulp has better product quality and heating efficiency, lower cost and better reliability than feedback temperature control systems. The optimal process parameters for pulsed microwave drying were microwave duty cycle of 0.6, pulse period of 17 seconds, air velocity of 1.9 m/s, and drying time of 12.5 minutes. Compared with continuous microwave drying, pulsed microwave drying resulted in the highest quality of dried pulp as a 35.31%±0.55% increase in anthocyanin retention, a 33.59%±0.23% increase under feedback temperature control, a 16.42%±0.18% increase under intermittent microwave drying. Pulsed microwave drying can control the power to reduce the dried fruit pulp temperature, improve the uniformity of post-drying quality and provide a basis for the industrial production of dried raspberry products.

The gardenia flower not only has extremely high ornamental value but also is an important source of natural food and spices, with a wide range of uses. To support the development of gardenia flower products, this study used headspace gas chromatography–ion mobility spectrometry (HS-GC–IMS) technology to compare and analyze the volatile organic compounds (VOCs) of fresh gardenia flower and those after using four different drying methods (vacuum freeze-drying (VFD), microwave drying (MD), hot-air drying (HAD), and vacuum drying (VD)). The results show that, in terms of shape, the VFD sample is almost identical to fresh gardenia flower, while the HAD, MD, and VD samples show significant changes in appearance with clear wrinkling; a total of 59 volatile organic compounds were detected in the gardenia flower, including 13 terpenes, 18 aldehydes, 4 esters, 8 ketones, 15 alcohols, and 1 sulfide. Principal component analysis (PCA), cluster analysis (CA), and partial least-squares regression analysis (PLS-DA) were performed on the obtained data, and the research found that different drying methods impact the VOCs of the gardenia flower. VFD or MD may be the most effective alternative to traditional sun-drying methods. Considering its drying efficiency and production cost, MD has the widest market prospects. [ABSTRACT FROM AUTHOR]

Copyright of Science & Technology of Food Industry is the property of Science & Technology of Food Industry Editorial Office 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.)

Pereskia bleo, a widely cultivated plant known for its medicinal applications, contains abundant phytochemicals, including phenolics and flavonoids, predominantly in its leaves. The drying process, a standard practice for enhancing the shelf life, could affect the bioactive compounds within the leaves. Therefore, this study aims to evaluate the impact of various drying methods on the colour, total phenolic content, flavonoid content, and antioxidant activity of P. bleo leaves. The tested drying methods include shade, oven, microwave, and freeze-drying. The colour of fresh and dried leaves was assessed using a Minolta chromameter. The total phenolic content (TPC) and total flavonoid content (TFC) of the P. bleo leaves extracts were determined using the Folin-Ciocalteu's and aluminium chloride colourimetric assay, respectively. Antioxidant capacities were analysed with DPPH radical scavenging and ferric- reducing antioxidant power assay (FRAP). The results showed that microwave drying has significantly less impact than the other drying methods on the colour attributes of the leaves (p<0.05). Notably, microwave-dried P. bleo leaves demonstrated significantly higher TPC (77.31 ± 0.70 mg GAE/g dry extract) and TFC (35.79 ± 1.34 mg QE/g dry extract) compared to leaves dried using the other tested methods (p<0.05). Additionally, microwave-dried P. bleo leaves displayed the highest DPPH inhibition (91.62%) and exhibited the most potent IC50 value (76.90 ± 1.06 µg/mL) compared to oven and shade-dried leaves (p<0.05). P. bleo leaves dried with a microwave also recorded a significantly higher FRAP value (62.66 ± 0.10 µg TE/g dry extract) than oven-dried leaves (p<0.05). In conclusion, microwave drying emerged to be an efficient drying method in preserving the colour and antioxidant properties of the P. bleo leaves, suggesting its potential as a favourable drying technique for retaining bioactive compounds in medicinal plant materials. [ABSTRACT FROM AUTHOR]

Basil is a highly valued aromatic plant worldwide, and drying is one of the best ways to preserve its leaves. Through a theoretical approach, the microwave drying of basil leaves can be modeled, and the effective diffusivity can be determined. However, using a model that considers moisture diffusion in the presence of intensive microwave energy is crucial. This study proposed a theoretical model to simulate the microwave drying of basil leaves in a thin layer. The model assumed that the material is homogeneous and isotropic, with the effective diffusivity depending on the microwave power. The model was solved numerically and validated with experimental data. The study also examined the effect of the microwave power on the color and bioactive properties during drying. The drying time was reduced by 60%, by increasing the microwave power from 199 W to 622 W. The effective diffusivity was found to be directly proportional to the microwave power. Drying at low powers was found to cause basil pigment degradation. However, drying at a power of 622 W resulted in better preservation of the leaves without browning. Finally, microwave drying negatively affects the bioactive compounds, as the phenolic content and antioxidant capacity in all the powers evaluated were significantly lower than in fresh basil leaves. [ABSTRACT FROM AUTHOR]

To elucidate the effects of energy input modes on energy efficiency and berry quality in continuous microwave drying, four energy input modes with variational working ways of magnetrons were investigated by using numerical simulation and bench experiments in a continuous microwave dryer. Energy efficiency was divided into absorption and conversion efficiency to study the change rule of drying process, and the retention rate of anthocyanins of berry's representative nutrition ingredient was studied considering both of the temperature and its uniformity. Results indicate that the energy input modes affect the absorption efficiency by changing the distribution uniformity of electric field of material layer, and the conversion efficiency by altering the matching degree between the energy allocation and drying characteristics of berry, which are both determined by the ways of working magnetrons of different energy input modes. The conversion efficiency has a greater influence on the final energy efficiency, so the energy input mode should be paid attention to the provision of microwave energy by selecting proper way of working magnetrons according to the drying characteristics. The effect of temperature uniformity on anthocyanin degradation is more obvious with average temperature increasing gradually, where better uniformity of electric field strength should be provided to guarantee the quality of dried berry by adjusting the energy input mode. The research results provide significant insights to optimize the energy input mode of taking into account both the energy efficiency and dried quality of material. [ABSTRACT FROM AUTHOR]

The distinctive pharmacological characteristics of Chinese medicinal herbs are rendering them increasingly popular as functional foods. However, fresh herbs are prone to mold and decay. Currently, drying processing is primarily employed to extend the storage time and effectively preserve the bioactive constituents of these herbs. After examining of the recent literatures on drying Chinese medicinal herbs, this paper provides a comprehensive overview of various drying technologies, including shade drying, hot air drying, solar drying, heat pump drying, microwave drying, far-infrared drying, vacuum drying, vacuum freeze drying, radio frequency drying, high voltage electric field drying and some combined techniques. While, an extensive illustration for each drying method principles, advantages/disadvantages, potential improvements and deep investigation of its energetic performance and the influence on the main active components in the drying process, such as polysaccharides, polyphenols, flavonoids, saponins, volatile oils, were summarized. The results showed that the combined drying technology not only had high efficiency and low energy consumption, but also preserved the bioactive medicinal components and sensory quality at the best. This paper provides a theoretical foundation and vast technical support for enhancing the value of Chinese medicinal herbs utilization and drying industry. [ABSTRACT FROM AUTHOR]

Summary: Boiling, centrifuging and various drying techniques (vacuum freeze‐drying (VFD), vacuum drying (VD), hot‐air drying (HAD) and microwave drying (MWD)) were assessed for their impact on bioactive compounds in Antarctic krill meal. A comparison between the raw and boiling groups revealed a significant degradation and isomerisation of astaxanthin, accompanied by a 1.25‐fold and 1.32‐fold increase in saturated (SFAs) and monounsaturated fatty acids (MUFAs), respectively. Drying was the primary factor responsible for the reduction in phospholipids, α‐tocopherol and polyunsaturated fatty acid (PUFAs), in combination with the increase in thiobarbituric acid‐reactive substances. For different drying methods, it was found that HAD induced severe lipid oxidation. In contrast, the VFD, VD and MWD improved lipid quality, reducing thiobarbituric acid‐reactive substances (TBARS) by 13–22% and increasing phospholipids by 1.08–1.11 times compared to HAD. VD preserved higher levels of bioactive compounds. PLS‐DA analysis identified 13‐cis‐astaxanthin, α‐tocopherol and eleven fatty acids as key indicators for Antarctic krill meal. [ABSTRACT FROM AUTHOR]