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The objective of the study was to whether the microwave vacuum drying system, which makes positive contributions to the quality characteristics in food drying, would have positive effects on the existing quality criteria by using explosion puffing drying after microwave vacuum drying and microwave vacuum drying after hot air drying. In this study, apple slices were dried in four single drying; air drying (AD) (70 °C, 2 m/s), microwave vacuum drying (MWVD) (1.5, 3 and 4.5 W/g) and six combined drying; the first 3 of 6 combined drying; AD (70 °C, 2 m/s) + MWVD (1.5, 3 and 4.5 W/g), the second 3 of 6 combined drying; MWVD (1.5, 3 and 4.5 W/g) + Explosion puffing drying (EPD) (0.6 MPa, 70 °C). It was determined that the apparent volumes of MWVD samples (1.5, 3 and 4.5 W/g) were 9, 17, and 51% higher than AD samples, respectively. With the MWVD and EPD processes applied after AD, a product structure with expanded and increased porosity was obtained, which increased the rehydration rate of the dried product. This was confirmed by the image analysis method, and the geometric structure, dimensions, and depth map of the porous material were examined using the MATLAB program for SEM images of dried products. We believe that a verification approach that is not available in the literature will contribute to the literature by providing an innovative approach for validation purposes in the evaluation of SEM images in drying studies. The total phenolic content (TPC), 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2.2’ azinobis 3-ethylbenzothiazoline-6-sulfonic acid (ABTS) contents were higher in the MWVD samples than in the MWVD + EPD samples. TPC and antioxidant capacity were higher 2–1.87 times and 1.98–1.74 times for 4.5 W/g MWVD and 4.5 W/g MWVD + EPD dried apple as compared to air-dried apple slice. With the increase in power density per product in MWVD, the porosity, rehydration, total phenolic, DPPH and ABTS values of the product increased The MWVD and EPD methods prevent shrinkage and volume loss of the dried products, and a low bulk density product was obtained. Therefore, we can conclude that both puff drying and microwave -vacuum drying are successful methods for the production of dried apple slices.

Drying herbs is a crucial method for stabilizing and preserving their essential properties and bioactive compounds. Although freeze drying is the preferred method for most herbs, it is expensive due to high energy consumption and operating costs. Biflavonoids are dimeric flavonoids that have recently been recognized as potential molecules possessing biological activities, such as antiviral and antimicrobial activity, and as effective molecules for the treatment of neurodegenerative and metabolic diseases and for cancer therapies. In this study, we performed a comparative analysis of freeze drying, air drying and oven drying to evaluate their effects on biflavonoid content in yellow ginkgo leaves (Ginkgo biloba L.). After drying, we performed spectrophotometric analysis to determine the browning index, pigments, phenolic compounds and antioxidant activity, while HPLC-DAD was used for the identification and quantification of individual biflavones (amentoflavone, bilobetin, ginkgetin, isoginkgetin and sciadopitysin). The most abundant biflavonoids were isoginkgetin and bilobetin, the amounts of which exceeded 1000 µg/g dw in all leaf samples. They were followed by ginkgetin and sciadopitysin, the amounts of which were about 30% lower. The drying method did not influence biflavone content or the total carotenoids, total polyphenols and total flavonoids. Consequently, our study suggests that all three methods may be used for the preparation of yellow ginkgo leaves as a source of biflavones and other bioactive compounds. [ABSTRACT FROM AUTHOR]

Almond bagasse resulting after the production of almond-based drinks represents a promising by-product with potential for use as a functional ingredient. To facilitate its utilization, the stability of this material can be achieved through dehydration processes such as hot air drying or freeze-drying. Nevertheless, owing to its high fat content, almond bagasse is prone to lipid oxidation, which could result in undesirable quality. Therefore, the objective of this work was to assess the impact of dehydration (by hot air drying at 60 and 70 °C and by freeze-drying) and storage (at room temperature and in accelerated conditions) on the functional quality and stability of almond bagasse powder. Throughout the dehydration process, it was observed that antioxidant compounds were preserved without significant differences among dehydration treatments. These compounds increased over the storage period, especially in the samples treated with hot air. Regarding antiradical capacity, the hot-air-dried samples showed higher values than the freeze-dried ones, although in all cases, it increased during storage. For total phenols in samples air-dried at 70 °C, increases of more than 50% were observed. The acidity and peroxide index were increased in the extended storage period, although they did not reach critical values. Samples stored for 180 days showed peroxide values ranging from 10 to 12.8 meq O2/kg dry matter for samples stored at room temperature and from 14.7 to 23 meq O2/kg dry matter for samples subjected to accelerated storage. [ABSTRACT FROM AUTHOR]

The need for cost-efficient, simple and radiation free technologies in clinical diagnostics has orientated the scientific community in the investigation of techniques such as vibrational spectroscopy. Vibrational spectroscopy due to its simplicity both in sample preparation as well as friendly use combined with the technological evolution in data processing and storage could play a promising role in diagnostics even for multifactorial diseases such as osteoarthritis via biofluid analysis. However, despite the related works aiming in synovial fluid there is not a common line in terms of sample preparation. Hence, it is important to establish an effective sample pretreatment protocol to avoid subjectivity and provide the possibility of reliable comparisons among results. In this work, freeze drying preprocessing technique was compared with natural drying in terms of diagnostic performance in 35 knee synovial fluids aspirated from primary osteoarthritic patients with 2 and 4 Kellgren-Lawrence scores. Principal component analysis combined with mean spectra analysis was implemented for this diagnostic purpose. Results have shown that natural drying technique tends to generate more distinct enhanced interclass variations among synovial dried samples compared to freeze drying, despite the latest potential in other biological samples. [ABSTRACT FROM AUTHOR]

Fresh and dried Cordyceps sinensis are widely used by the public for medicinal and health purposes. However, the differences between them have not been examined. In this study, fresh wild and artificial C. sinensis (WFC and AFC) were dried to obtain dried wild and artificial C. sinensis (WDC and ADC). Non-targeted GC-MS was used to analyze the metabolic profile characteristics of the four groups of samples. The results showed that air drying significantly altered the composition and content of C. sinensis, mainly in the form of higher abundance of organic acids and derivatives and lower abundance of lipids and lipid-like molecules in fresh C. sinensis. Hierarchical cluster analysis (HCA) and quantitative analyses showed that air drying increased the abundance of Valine, Zinniol, Urocanate, Vulpinic acid, and Uridine 5'-diphosphate, and decreased Xanthotoxol, Vitexin-4-o-glucoside, Val-trp, and Wogonin. These differentially accumulated metabolites (DAMs) were also shown to be potential biomarkers for C. sinensis. KEGG enrichment analysis identified lysine biosynthesis as the most significantly enriched pathway. Annotation of these DAMs to lysine biosynthesis revealed that citrate cycle and pyruvate metabolism entered lysine biosynthesis via 2-oxohlutarate and Homocitrate, respectively, resulting in significant enrichment of L-saccharopine and L-lysine content was significantly higher. Alanine, aspartate, and Glutamate metabolism synthesized more L-aspartate to promote L-lysine synthesis. Thus, high levels of L-lysine result in lysine degradation and pymolysine, which are the most active metabolic pathways during the drying of fresh C. sinensis and indirectly lead to differences in metabolic profiles. [ABSTRACT FROM AUTHOR]

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In this study, vacuum drying (VD), microwave drying (MW) and freeze-drying (FD) alternatives to air drying (AD) were applied to apple samples before explosion puffing drying (EPD). The volumes of AD+EPD samples were determined 20% higher than the volume of AD samples. The porosity value and the average pore radius value were obtained by examining the SEM images with the MATLAB program. Porosity values were found between 0.41-0.82 for all drying processes applied. The lowest porosity was found at 180MW, and the highest porosity was found in the FD samples. It is seen that the porosity ratio increases as the microwave power per product increases. Rehydration rates of 180, 360 and 600MW samples were determined as 308, 320 and 336%, respectively. It contributed to the increase in rehydration due to the increase in the porosity of the product with the increase in power density per product in MW drying. There was an increase in the amount of TPC with the combined use of the EPD process. The highest ABTS and DPPH were determined in the FD, FD+EPD and 600MW+EPD samples, respectively. The predrying methods and parameters described in the study significantly affected the quality of apples in terms of their physical and chemical properties. [ABSTRACT FROM AUTHOR]

Objective: This study aimed to improve the flavor of Cantonese sausage and innovate the product. Methods: The volatile flavor compounds in the Cantonese sausages containing sauce-flavor Baijiu air-dried for 0 day, 2 days and 4 days were detected by GC-MS, and the changes of volatile flavor compounds were analyzed by multivariate statistics. Results: A total of 39 volatile flavor compounds were detected through GC-MS technology, including 18 hydrocarbons, 12 esters, 2 aldehydes, 2 ethers, 1 alcohol, 1 acid, 1 ketone and 2 other compounds. Esters, aldehydes, alcohols and hydrocarbons significantly increased during air-drying, while ketones and ethers showed a trend of first increasing and then decreasing during air-drying. The acids did not change significantly during air-drying. Five different flavor substances were identified through VIP values, which could be served as potential biomarkers for distinguishing sausages with different air-drying times. Six key flavor components were screened through OAV. Ethyl 2-methylbutyrate, ethyl hexanoate, and ethyl butyrate were common key flavor components in three groups of sausages, and their content significantly increased during air-drying. Conclusion: Adding sauce-flavor Baijiu can increase the types and contents of volatile flavor compounds in Cantonese sausage and promote the formation of new flavor compounds.

In this study, solid olive mill waste (SOMW) was used to obtain antioxidant compounds using solid–liquid extraction. The effect of different extraction methods, namely microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), Soxhlet, and conventional solvent extraction, on the yield, total phenolics, and total antioxidant activity of SOMW extracts was investigated. Untreated and dried SOMW were subjected to extraction with water and methanol. The antioxidant activity of the extracts was evaluated using the DPPH assay, while their total phenolic content was measured using the Folin–Ciocalteu method. For the characterisation of the extracts, HPLC-DAD analysis was performed. The results showed that the extraction yield was significantly influenced (p < 0.05) by the solvent used, the material treatment prior to extraction, the moisture content of SOMW samples, and the extraction time. The optimised parameters were water, as the extraction solvent, and MAE as the extraction technique (extraction temperature of 50 °C and time of 1 h). The evaluation of the antioxidant activity of the extracts indicated that phenolics were the dominant bioactive compounds. The extracts were found to be rich in several hydroxytyrosol derivatives. Therefore, SOMW can be a valuable resource for bioactive compounds using conventional and innovative extraction techniques. [ABSTRACT FROM AUTHOR]

Recovering waste from industrial food processes and developing new healthy foods as plant protein sources has been a major focus of scientific research and industrial innovation in food. Thus, the consumption of plant-based beverages from soy, oat, or almond has been promoted. In the case of almonds, the resulting solid bagasse has an interesting nutritional profile and its transformation into a powdered product could be a valuable option for the food industry. The main objective of this work was to determine the effect of hot air drying at 60 and 70 °C and freeze-drying on the physicochemical, water interaction, emulsifying and antioxidant properties of powdered almond bagasse. Furthermore, hot air-drying curves have been modelled and isotherms at 20 °C have been performed. The proximate composition of the powder revealed a protein content of 15% and a fat content of 25%, which makes it a remarkably different powder from those obtained from other vegetable residues such as fruits and vegetables. This composition was decisive in the effect of the drying method and drying temperature, and no significant differences were observed on the physico-chemical or antioxidant properties regardless of the drying method used. However, freeze-drying resulted in a powder with a more homogeneous particle size distribution and better oil-interaction properties, especially with higher emulsifying activity and stability. [ABSTRACT FROM AUTHOR]

Drying herbs is a crucial method for stabilizing and preserving their essential properties and bioactive compounds. Although freeze drying is the preferred method for most herbs, it is expensive due to high energy consumption and operating costs. Biflavonoids are dimeric flavonoids that have recently been recognized as potential molecules possessing biological activities, such as antiviral and antimicrobial activity, and as effective molecules for the treatment of neurodegenerative and metabolic diseases and for cancer therapies. In this study, we performed a comparative analysis of freeze drying, air drying and oven drying to evaluate their effects on biflavonoid content in yellow ginkgo leaves (Ginkgo biloba L.). After drying, we performed spectrophotometric analysis to determine the browning index, pigments, phenolic compounds and antioxidant activity, while HPLC-DAD was used for the identification and quantification of individual biflavones (amentoflavone, bilobetin, ginkgetin, isoginkgetin and sciadopitysin). The most abundant biflavonoids were isoginkgetin and bilobetin, the amounts of which exceeded 1000 µg/g dw in all leaf samples. They were followed by ginkgetin and sciadopitysin, the amounts of which were about 30% lower. The drying method did not influence biflavone content or the total carotenoids, total polyphenols and total flavonoids. Consequently, our study suggests that all three methods may be used for the preparation of yellow ginkgo leaves as a source of biflavones and other bioactive compounds.

Elderflower extracts are known to be a source of valuable substances that show a wide spectrum of biological activity, including antibacterial and antiviral properties, which demonstrate a degree of effectiveness against SARS CoV-2. In this work, the influence of fresh inflorescence stabilisation methods (freezing, air drying, and lyophilisation) and extraction parameters on the composition and antioxidant properties of the extracts were studied. Wild elderflower plants growing in the Małopolska Region of Poland were studied. Antioxidant activities were evaluated by 2,2-diphenyl-1-picrylhydrazyl free radical-scavenging ability and ferric-reducing antioxidant power assays. The total phenolic content was determined using the Folin-Ciocalteu method and the phytochemical profile of the extracts was analysed using HPLC. The obtained results showed that the best method for the stabilisation of elderflower was lyophilisation, and the determined optimal maceration parameters were 60% methanol as a solvent and a process time of 1–2 days. [ABSTRACT FROM AUTHOR]

Almond bagasse resulting after the production of almond-based drinks represents a promising by-product with potential for use as a functional ingredient. To facilitate its utilization, the stability of this material can be achieved through dehydration processes such as hot air drying or freeze-drying. Nevertheless, owing to its high fat content, almond bagasse is prone to lipid oxidation, which could result in undesirable quality. Therefore, the objective of this work was to assess the impact of dehydration (by hot air drying at 60 and 70 °C and by freeze-drying) and storage (at room temperature and in accelerated conditions) on the functional quality and stability of almond bagasse powder. Throughout the dehydration process, it was observed that antioxidant compounds were preserved without significant differences among dehydration treatments. These compounds increased over the storage period, especially in the samples treated with hot air. Regarding antiradical capacity, the hot-air-dried samples showed higher values than the freeze-dried ones, although in all cases, it increased during storage. For total phenols in samples air-dried at 70 °C, increases of more than 50% were observed. The acidity and peroxide index were increased in the extended storage period, although they did not reach critical values. Samples stored for 180 days showed peroxide values ranging from 10 to 12.8 meq O2/kg dry matter for samples stored at room temperature and from 14.7 to 23 meq O2/kg dry matter for samples subjected to accelerated storage.

Fresh and dried Cordyceps sinensis are widely used by the public for medicinal and health purposes. However, the differences between them have not been examined. In this study, fresh wild and artificial C. sinensis (WFC and AFC) were dried to obtain dried wild and artificial C. sinensis (WDC and ADC). Non-targeted GC-MS was used to analyze the metabolic profile characteristics of the four groups of samples. The results showed that air drying significantly altered the composition and content of C. sinensis, mainly in the form of higher abundance of organic acids and derivatives and lower abundance of lipids and lipid-like molecules in fresh C. sinensis. Hierarchical cluster analysis (HCA) and quantitative analyses showed that air drying increased the abundance of Valine, Zinniol, Urocanate, Vulpinic acid, and Uridine 5’-diphosphate, and decreased Xanthotoxol, Vitexin-4-o-glucoside, Val-trp, and Wogonin. These differentially accumulated metabolites (DAMs) were also shown to be potential biomarkers for C. sinensis. KEGG enrichment analysis identified lysine biosynthesis as the most significantly enriched pathway. Annotation of these DAMs to lysine biosynthesis revealed that citrate cycle and pyruvate metabolism entered lysine biosynthesis via 2-oxohlutarate and Homocitrate, respectively, resulting in significant enrichment of L-saccharopine and L-lysine content was significantly higher. Alanine, aspartate, and Glutamate metabolism synthesized more L-aspartate to promote L-lysine synthesis. Thus, high levels of L-lysine result in lysine degradation and pymolysine, which are the most active metabolic pathways during the drying of fresh C. sinensis and indirectly lead to differences in metabolic profiles.

Būt (Sideroxylon mascatense) is an indigenous wild blueberry found in Oman. It has a very short season and is commonly preserved by drying. The aims of this study were to determine the physico-chemical characteristics and stability of phytochemicals (i.e., polyphenols and flavonoids) in the berries during drying (i.e., freeze-drying at −40 °C and air-drying at 60 and 90 °C) and the polyphenol stability of the dried berries as a function of storage temperature (i.e., 90, 70, 60, 40, 20, and −20 °C). The moisture content of fresh berry flesh was 64.5 g/100 g sample (wet basis). The crude protein and fat contents were higher in the seeds than in the flesh. Glucose and fructose were the main sugars and their concentrations were highest in the sample air-dried at 60 °C. The initial total polyphenol content (TPC) and total flavonoid content (TFC) of the flesh were 2.009 mg gallic acid equivalent (GAE)/g dry-solids and 0.199 mg catechin equivalent (CE)/g dry-solids, respectively. The samples air-dried at 90 °C and freeze-dried at −40 °C had higher TPC (i.e., 2.638 mg GAE/g dry-solids) and TFC (i.e., 0.395 mg CE/g dry-solids), respectively. There was a significant difference between the TPC and TFC of fresh and dried wild berries (p < 0.05). The freeze-dried wild berries retained a high TPC compared to the air-dried samples. The polyphenol storage stability of freeze-dried wild berries at different storage temperatures showed two phases: an initial release phase followed by a decay phase. The polyphenol storage stability was modeled using the Peleg model and the kinetic parameters were correlated with the storage temperature. [ABSTRACT FROM AUTHOR]

The paper presents the results of a survey performed in ten Romanian wood-processing companies which dry oak lumber (mainly Quercus petraea and Quercus robur, but also Quercus cerris). The purpose of this survey was to establish the current conditions applied for carrying out the drying process for these species, and to establish the aspects which need to be improved, according to the industrials' opinion. The results of this survey show the present level of applied knowledge concerning the drying of these species, but also some shortcomings that are prone to optimization. The information synthetized from the survey is to be used as starting point to set-up a plan for the scientific investigation of the conventional drying of oak lumber, especially of Quercus cerris, which has been less studied so far. Improving the drying uniformity, reducing the proportion of cracks, and drying time reduction are the main targets envisaged. [ABSTRACT FROM AUTHOR]

In this study, solid olive mill waste (SOMW) was used to obtain antioxidant compounds using solid–liquid extraction. The effect of different extraction methods, namely microwave-assisted extraction (MAE), ultrasound-assisted extraction (UAE), Soxhlet, and conventional solvent extraction, on the yield, total phenolics, and total antioxidant activity of SOMW extracts was investigated. Untreated and dried SOMW were subjected to extraction with water and methanol. The antioxidant activity of the extracts was evaluated using the DPPH assay, while their total phenolic content was measured using the Folin–Ciocalteu method. For the characterisation of the extracts, HPLC-DAD analysis was performed. The results showed that the extraction yield was significantly influenced (p < 0.05) by the solvent used, the material treatment prior to extraction, the moisture content of SOMW samples, and the extraction time. The optimised parameters were water, as the extraction solvent, and MAE as the extraction technique (extraction temperature of 50 °C and time of 1 h). The evaluation of the antioxidant activity of the extracts indicated that phenolics were the dominant bioactive compounds. The extracts were found to be rich in several hydroxytyrosol derivatives. Therefore, SOMW can be a valuable resource for bioactive compounds using conventional and innovative extraction techniques.

The shrinkage of the connective tissue and myofiber of lamb meat submitted to heat treatment or air drying at different storage stages (1, 5 and 7 days) was evaluated herein. The longitudinal and transverse shrinkage of heated lamb meat was significantly influenced by storage time and water bath heating temperature (50 °C, 70 °C and 90 °C) (p < 0.001). In contrast, the shrinkage of air-dried lamb meat was not influenced by storage time (p > 0.05). The microstructure of heated lamb meat, namely, the distance between muscle fascicles, the distance between myofibril networks, the area of myofibril networks, and the endomysium circumference, was significantly influenced by storage time (p < 0.05). During storage, the proportion of muscle fibers completely detached from endomysium increased, which could be due to the progressive degradation of proteins linking the endomysium and myofibril, including β-dystroglycan, α-dystroglycan, integrin-β1, and dystrophin. However, degradation of such proteins did not influence the shrinkage of lamb meat stored for five days or longer, since the decreased distance between myofibril networks indicated a higher shrinkage ratio of the endomysium compared to myofibers in samples air-dried at 35 °C or heated at 90 °C. The effect of these proteins on the shrinkage of heated lamb meat (raw meat stored for 1 day or less time) requires further elucidation. [ABSTRACT FROM AUTHOR]

Būt (Sideroxylon mascatense) is an indigenous wild blueberry found in Oman. It has a very short season and is commonly preserved by drying. The aims of this study were to determine the physico-chemical characteristics and stability of phytochemicals (i.e., polyphenols and flavonoids) in the berries during drying (i.e., freeze-drying at −40 °C and air-drying at 60 and 90 °C) and the polyphenol stability of the dried berries as a function of storage temperature (i.e., 90, 70, 60, 40, 20, and −20 °C). The moisture content of fresh berry flesh was 64.5 g/100 g sample (wet basis). The crude protein and fat contents were higher in the seeds than in the flesh. Glucose and fructose were the main sugars and their concentrations were highest in the sample air-dried at 60 °C. The initial total polyphenol content (TPC) and total flavonoid content (TFC) of the flesh were 2.009 mg gallic acid equivalent (GAE)/g dry-solids and 0.199 mg catechin equivalent (CE)/g dry-solids, respectively. The samples air-dried at 90 °C and freeze-dried at −40 °C had higher TPC (i.e., 2.638 mg GAE/g dry-solids) and TFC (i.e., 0.395 mg CE/g dry-solids), respectively. There was a significant difference between the TPC and TFC of fresh and dried wild berries (p < 0.05). The freeze-dried wild berries retained a high TPC compared to the air-dried samples. The polyphenol storage stability of freeze-dried wild berries at different storage temperatures showed two phases: an initial release phase followed by a decay phase. The polyphenol storage stability was modeled using the Peleg model and the kinetic parameters were correlated with the storage temperature.

Sediment humic substance (SHS) is a highly heterogeneous and complex organic mixture with a broad molecular weight range. It is the significant component that associates distribution, transport, and biotoxicity of pollutants in a river environment. Air- and freeze-drying sediment pre-treatment may cause different biological activity and may result in different chemical quantities and sediment organic matter. This study collected sediments that received livestock wastewater discharge. The sediments were air- (AD) and freeze-dried (FD). The dried sediment organic matter was extracted with an alkaline solution and separated into three size-fractioned SHS samples. Size-fractioning is an effective method used to differentiate materials, on a molecular level. The bulk solution (<0.45 μm) was designated as BHS, and size-fractioned solutions were identified as LHS (<1 kDa), MHS (1–10 kDa), and HHS (10 kDa–0.45 μm). The AD SHS had a lower dissolved organic carbon (DOC) concentration than the FD SHS for the bulk and individual size-fractioned SHS, but the AD and FD SHS had a similar distribution of organic carbon in the size-fractioned SHS. The AD SHS had higher aromaticity (SUVA254) and an extent of humification (HIX) than the FD SHS. In addition, the high molecular weight SHS (HHS) had a higher SUVA254 but lower HIX than the MHS and LHS. The HHS had significantly lower fulvic acid but had higher humic acid-like substances than the MHS and LHS. This is possibly the reason the LHS had a higher humification degree but lower aromaticity than HHS. The size-fractioned SHS and optical indicators distinguished the difference between the chemical properties when air- or freeze-dried, due to the different degree of biological activities. [ABSTRACT FROM AUTHOR]

• The organic-inorganic network imparts rigidity and strength to cellulose-based foams. • Foaming and air drying enable scalable production of cellulose-based foams. • Cellulose composite foams combine high compressive strength with low density. • Cellulose composite foams possess recyclability, biodegradability, and scalability. Lightweight and high-strength cellulose-based foams have gained increasing momentum due to their combination of sustainability and high performance. However, complex modification to cellulose fibers can sacrifice the environmental friendliness and further limit productional scalability. Here, we engineer lightweight yet strong cellulose-based foams made from mechanically treated microfibrillated cellulose (MFC), reinforced by organic-inorganic network, and scaled by surfactant foaming combined with air drying. Consisting of strong coordination and extensive secondary interaction within the organic-inorganic network, the resulting cellulose composite foams achieve both a high compressive modulus of 451.3 kPa and a yield strength of 25.1 kPa at a low density of 32.9 mg cm−3, which exceed other MFC-based foams based on surfactant foaming. In addition, the incorporation of the organic-inorganic network has no negative effect on the scalability, recyclability, or biodegradability of cellulose composites foam, making closed-loop material recycling possible. The life-cycle assessment reveals that replacing petroleum-based foams with our cellulose composite foams result in substantial reductions in carbon emissions. The structural design and manufacturing of our cellulose-based foam can stimulate market interest for cellulose foam and the development of the bioeconomy. [ABSTRACT FROM AUTHOR]

The shrinkage of the connective tissue and myofiber of lamb meat submitted to heat treatment or air drying at different storage stages (1, 5 and 7 days) was evaluated herein. The longitudinal and transverse shrinkage of heated lamb meat was significantly influenced by storage time and water bath heating temperature (50 °C, 70 °C and 90 °C) (p < 0.001). In contrast, the shrinkage of air-dried lamb meat was not influenced by storage time (p > 0.05). The microstructure of heated lamb meat, namely, the distance between muscle fascicles, the distance between myofibril networks, the area of myofibril networks, and the endomysium circumference, was significantly influenced by storage time (p < 0.05). During storage, the proportion of muscle fibers completely detached from endomysium increased, which could be due to the progressive degradation of proteins linking the endomysium and myofibril, including β-dystroglycan, α-dystroglycan, integrin-β1, and dystrophin. However, degradation of such proteins did not influence the shrinkage of lamb meat stored for five days or longer, since the decreased distance between myofibril networks indicated a higher shrinkage ratio of the endomysium compared to myofibers in samples air-dried at 35 °C or heated at 90 °C. The effect of these proteins on the shrinkage of heated lamb meat (raw meat stored for 1 day or less time) requires further elucidation.

The hot air convective drying of blueberries (Vaccinium corymbosum) in a thin layer was performed using a laboratory-scale dryer. The experiments were carried out at drying air temperatures of 60, 70 and 80 o C, and drying air velocities of 0.5 and 1.5 m/s. At higher values of the drying air temperature and the drying air velocity, less time was required for the convective drying of blueberries, i.e. the drying time of blueberries decreased with increasing drying air temperatures and velocities. The experimental data obtained during the drying process were fitted to ten different mathematical models. The Midilli et al. model was found to be the most appropriate model for explaining the drying behavior of blueberries during convective drying. Effective moisture diffusion coefficients were calculated using the Fick's diffusion model, ranging from 9.66 x 10-12 m2 /s to 9.67 x 10-11 m2 /s. These values were found to increase proportionally with the increase in drying air temperatures and velocities. The lowest total color change and shrinkage of dried blueberries were recorded during freeze drying. A water activity less than 0.6 was measured at a blueberry moisture content of 0.235 kgw/kgd.m, a drying air temperature of 26 o C and a relative air humidity of 60 %.

Ginger rhizome (Zingiber officinale) is widely used as a spice or as a medicinal plant. The major bioactive compound in fresh ginger rhizome is 6-gingerol and it is known for having a number of physiological effects. This compound is heat-sensitive and during cooking or drying will transform into 6-shogaol. Hence, the 6- gingerol content is used to evaluate the quality of dried ginger. The content of 6-gingerol during drying was measured using HPLC. Several factors that could affect the 6-gingerol content were considered and a predictive model for changes in 6-gingerol has been developed from the experimental data. The predictive model includes a single term drying model that predicts the changes of moisture content during drying. Drying time and relative humidity (ranging from 10% to 40%) impacted 6-gingerol content whereas drying air temperature (ranging from 30ºC to 60ºC) had a lesser effect. It was also found that the 6-gingerol content in fresh rhizomes was highly variable and thus required thorough testing prior to drying to be able to make the prediction more accurate.

The influence of air-drying (AD), convection oven (CO) and solar drying (SOD) on the physical and chemical properties of Ilex guayusa leaves is discussed. Total ash (%), acid-insoluble ash (%), watersoluble ash (%), residual moisture (%) and caffeine content (%) were estimated. Additionally, alkaloids, flavonoids, reducing sugars, saponins, steroids, quinones, fats, phenols and tannins detection of dry leaves extracts were assessed. The results revealed that parameters of physical analysis were not affected by the drying techniques. The highest amount of secondary metabolites in ethanol and aqueous extracts were detected. In general, convection oven dried leaves showed the highest caffeine content (3.71%) and the lowest drying time (13 h) compared to other drying methods. The results revealed a fast method to dry Ilex guayusa leaves and indicate that this species possess a variety of bioactive compounds beneficial for health. Our results revealed an effective quick method to dry Ilex guayusa leaves without altering the content of beneficial bioactive components.

An original drying process combining air impingement and intermittent drying was studied on apple slices and mango cubes. The influence of four operating parameters (air velocity, drying/tempering periods, upper height, and air temperature) on the drying time and on the drying rate was evaluated. Continuous and intermittent drying were compared. The intermittency α = 1/7 (τon = 10 seconds and τoff = 60 seconds) gave the best results. A time savings of 54% for apple and 67% for mango was reached. In continuous drying, a time savings of 4620 seconds was observed by increasing the air velocity from 6 to 40 m s−1 for apple. Air temperatures of 328 K for apple and of 328 K or 338 K for mango were determined as optimum to prevent case‐hardening. Experimental results were fitted with the analytical solution of Fick's second law and the modified Page equation (average values R2 = 0.985 and 0.961, for apple and mango, respectively). For both products, the apparent moisture diffusivity Dapp, the drying constant k, the drying coefficient n, and the activation energy Ea, were identified. Activation energies calculated from the analytical solution were 30.3 and 36.8 kJ mol−1 and were 25.4 and 30.0 kJ mol−1 using the modified Page equation for apple and mango, respectively. Mango has an increased temperature sensitivity and thus will need less energy for drying than apple. [ABSTRACT FROM AUTHOR]

The most important chemicals common in Moringa oleifera Lam. leaves are polyphenols and tannins. They are synthesised during development and the amount and composition are primarily dependent on environmental conditions and factors such as leaf harvesting. Trials were conducted in the Gauteng Province at the University of Pretoria Experimental Farm on Hillcrest Campus (250 45′ 08.6″S, 280 15′ 30.S" E), with an altitude of 1372 m above sea level and an average annual rainfall of 640 mm. Five year old M. oleifera tree orchard were used for this study and treatments were laid in a randomised complete block design, where 12 plants were used in each plot within a row, with a plant spacing of 2 × 2 m2. Partial harvesting was done at 25% leaf removal, while severe leaf harvesting was done at 75% leaf removal. The control trees were not harvested, but only leaf (mature and immature) samples were harvested for analyses. Leaf samples from all plots were harvested in September, November, February and May in years 1 and 2. Leaf samples (equal quantities of immature and mature leaves) from partially, severely harvested and control plots were harvested and separated into batches, one to be analysed as fresh material and the other as dry material. The dry material was placed in paper bags and allowed to immediately air dry under normal room conditions of 26 °C. Partially harvested M. oleifera leaves produced an increased accumulation of total phenolic content (TPC) 35–44 g/kg dry weight, from spring to summer season, in comparison to severe harvesting 26–35 g/kg dry weight. With severe leaf harvesting (75%), because of probable lower photosynthetic capacity, phenols across September to May of years 1 and 2 decreased. The onset of low temperatures in May resulted mostly higher TPC and tannin build up, which means that cold stress may improve more bio-active compounds in the leaves. Dark and fully developed mature leaves mainly contained the highest amount of TPC. Moringa oleifera leaves collected and dried at each harvesting interval, instead of freshly milled, do show the same quantity of TPC and tannins across the season illustrating that air drying can be used as a post-harvest handling technique, extending shelf life without losses of vital phenols. With harvesting severity as a concern in Moringa , this study confirms that the TPC and tannins in mature and immature leaves did not rise to toxic levels for human consumption. • Partial leaf harvesting is a good harvesting practise for Gauteng province, SA. • Low temperatures may result in higher TPC and tannin build up in leaves. • Air dried Moringa leaves do not lose more TPC in comparison to freshly harvested leaves. • Air drying is recommended to extend shelf life of Moringa leaves. [ABSTRACT FROM AUTHOR]

The objective of this research was to investigate the influence of osmotic dehydration as a pre-treatment to the air drying of strawberries. Fresh, untreated strawberries were sliced and dried in a sucrose solution at a temperature of 50 oC and concentrations of 50 and 65 oBx. After osmotic dehydration, the slices were dried in a thin layer at air temperatures of 60, 70 and 80 oC, and an air velocity of 1 m/s. After osmotic dehydration, the moister content and solid gain at a sucrose solution concentration of 55 oBx were 3.44 gw/gdm and 0.062 gdm/g, respectively. However, the moister content and solid gain in at a sucrose solution concentration of 65 oBx were 4.08 gw/gdm and 0.0944 gdm/g (65 oBx), respectively. The effective moisture diffusivity of air drying varied from 1.57 x 10-9 to 4.43 x 10-10 m/s2, increasing with an increase in air temperatures and decreasing with an increase in pretreatment source concentrations. Lower air temperatures exert a positive influence on the rehydration time. A shorter air drying process positively affects the total changes in colour. The impact of pretreatment on colour changes in strawberries was not recorded after drying.

Sediment humic substance (SHS) is a highly heterogeneous and complex organic mixture with a broad molecular weight range. It is the significant component that associates distribution, transport, and biotoxicity of pollutants in a river environment. Air- and freeze-drying sediment pre-treatment may cause different biological activity and may result in different chemical quantities and sediment organic matter. This study collected sediments that received livestock wastewater discharge. The sediments were air- (AD) and freeze-dried (FD). The dried sediment organic matter was extracted with an alkaline solution and separated into three size-fractioned SHS samples. Size-fractioning is an effective method used to differentiate materials, on a molecular level. The bulk solution (254) and an extent of humification (HIX) than the FD SHS. In addition, the high molecular weight SHS (HHS) had a higher SUVA254 but lower HIX than the MHS and LHS. The HHS had significantly lower fulvic acid but had higher humic acid-like substances than the MHS and LHS. This is possibly the reason the LHS had a higher humification degree but lower aromaticity than HHS. The size-fractioned SHS and optical indicators distinguished the difference between the chemical properties when air- or freeze-dried, due to the different degree of biological activities.

This paper considers the thermal design and the experimental testing of a heat pipe (thermosyphon) heat exchanger for a relatively small commercially available mini-drier. The purpose of the heat exchanger is to recover heat from the moist waste air stream to preheat the fresh incoming air. The working fluid used was R134a and the correlations are given for the evaporator and condenser inside heat transfer coefficients as well as for the maximum heat transfer rate. The theoretical model and computer simulation program used for the thermal design calculations are described. The validity of the as-designed and manufactured heat exchanger coupled to the drier is experimentally verified. The theoretical model accurately predicted the thermal performance and a significant energy savings and a reasonable payback period was achieved.

ABSTRACT The heterogeneous behavior of wood during drying is a process difficult to control. The objective of this study was to evaluate the accuracy of the neuro-fuzzy hybrid system for monitoring wood moisture during drying. Eucalyptus urophylla x Eucalyptus grandis samples (2 x 2 x 4 cm) were saturated and dried in climatic chamber for 15 days. Basic density was determined by the dry mass/saturated volume ratio. Two neuro-fuzzy systems were developed to monitor wood moisture, the first based on the genetic material and drying period and the second based on basic density and drying period. The drying rate of wood samples was higher at the initial period and all reached equilibrium moisture content after 15 days. Density showed relationship with wood moisture during the study period. Both systems have the potential to monitor moisture, however, neuro-fuzzy system based on basic density and drying period showed better results and is therefore more suitable.

Intensification of large-scale urea production is an urgent task. One of the factors restraining the increase in urea production is the insufficient performance of the granulation tower, in which outside air is supplied from below to cool the freely falling drops of urea alloy. Three methods of preparation of air supplied to the lower part of the granulation tower are considered. It is shown that the first two methods cannot significantly increase the tower productivity. The third method has great capabilities, in the implementation of which air cooling is organized in a hollow nozzle water scrubber. With this approach, it is also possible to significantly reduce the dimensions of the heat exchanger-evaporator, since it can be installed on the stream of water circulating in the scrubber, and not on the air stream. Calculations have been made for three options for air supply to the granulation tower, which differ from each other in the conditions of air intake in front of the K-664A (or K-664V) pressure axial fan. The first option meets the summer operating conditions of the tower, when the outside air temperature is 35 °C. The second option corresponds to normal operating conditions at an air temperature of 20 °C. When using the third option, it was assumed that the temperature of the air processed in the scrubber decreases from 35 to 7 °C. The calculations were carried out taking into account not only the changing temperature and relative humidity of the outside air, but also the supply of heat to the processed air, which is equivalent to the power of the forced fan. The conditions of heat exchange between heated air and cooled urea in the fluidized bed apparatus were taken into account. The performed calculations allow using the aggregated machine WOC-100 manufactured by «McQuay» (USA) for air cooling with two centrifugal compressors operating on R134a. When the granulation tower operates according to the second option, when in hot weather (May-October) air is supplied to it, cooled in a scrubber to 20 °C, approximately 40,000 tons of granular urea can be produced additionally. [ABSTRACT FROM AUTHOR]

Sawn timber of chestnut (Castanea sativa Mill) wood, 50mm thick, was used for kiln drying and air drying, in Central Greece (Karditsa). Drying schedules used for kiln drying showed a good performance. In air drying, it is possible to obtain wood moisture content from around 70% to less than 20%, in a rather short period (3 months) during summer. On the contrary, during winter time air drying is slow and moisture content below 18% can't be achieved before mid of May. Based on the quality assessment of kiln and air dried sawn timber, only minor defects were observed. Ring shakes and discoloration were absent, while case-hardening and a little honeycombing were observed. The overall conclusion of this research is that chestnut wood is suitable for any outdoor and indoor use after being kiln- and/or air-dried. [ABSTRACT FROM AUTHOR]

Highlights • Wet porous medium air-drying behaviors are studied numerically and experimentally. • The medium surface is assumed to undergo the fully wet, partly wet, and fully dry stages. • A water film coverage model is proposed to describe the medium surface moist situation. • Air-drying experiments on a wet sand layer are conducted to validate the model. • The present model can better predict the experiments than the traditional model. Abstract A novel model named the water film coverage model is proposed to quantitatively describe the surface moist situation of a wet porous medium during its convective air-drying process, it assumes that the medium surface exposed to hot air undergoes three stages, i.e. the fully wet, partly wet, and fully dry stages, as compared to the two stage assumption made by the traditional model. The model contains two parameters including the critical water saturation at medium surface at which the water film begins to break, and the coverage constant that characterizes the water film coverage. By combining this new model with our previous porous medium air-drying model, which considers a variety of transport mechanisms and uses the specific humidity as the convective moisture transfer driving potential, a comprehensive model for predicting the air-drying process of a wet porous medium is obtained. Air-drying experiments are conducted to validate the model, they are carried out on a wet sand layer, which consists of silica sand and distilled water and has a thickness of 15 mm, for hot air temperatures of 318.15, 333.15 and 348.15 K. The experimental results show that the sand layer temperature continuously increases throughout the drying process, there is no period during which the sand layer temperature remains constant at the air wet-bulb temperature, as predicted by the traditional model. Comparison of the simulations and experiments supports that the present model can better predict the sand layer temperature and moisture content evolutions than the traditional model. The critical water saturation has a value close to the initial water saturation of the wet sand layer, while the coverage constant takes a value less than unity, which corresponds to an upward convex coverage curve. The present model will reduce to the traditional model when the critical saturation is taken to be equal to the irreducible saturation or the coverage constant is set to be zero. [ABSTRACT FROM AUTHOR]

Radiant Energy Vacuum (REV)-dried broccoli, oranges, and carrots prepared by the optimal drying protocols determined in this study were compared to the freeze-dried and air-dried samples based on the nutritional values before and after drying. An accelerated shelf-life study for REV-dried broccoli, oranges, and carrots was also conducted. For all the samples, REV drying significantly shortened the processing time. The REV-dried samples had much higher retention of the nutritional values (vitamin C, β-carotene) compared to the conventional air-drying process, and the values were also competitive to those of the freeze-dried samples. Although freeze-drying resulted in the best rehydration property, the REV-dried samples still earned the highest scores in the sensory test. In the accelerated shelf-life study conducted on the REV-dried samples, the moisture content and water activity stayed at the same level, but the nutritional values showed a downward trend. The sensory properties fluctuated in the shelf-life but still gained positive feedback from the panelists. Moreover, the testing method for β-carotene content was uniquely designed in this project and could be a semi-quantitative method to refer to.

The physico-chemical and microstructural changes of “Rojo Brillante” persimmons in two maturity stages (S1 and S2) were evaluated during air drying. The maturity stage influences moisture loss. A Moisture level of approximately 50%, a limit at which persimmons are considered semidried, was reached after 21 and 28 days for S1 and S2, respectively. Shrinkage resulting from water removal led to secondary epidermis formation concomitantly to internal flesh gelling, which was related to moisture loss and water activity changes of each fruit part. The thicker epidermis and the lower volume of gelled area inside the S1 fruits led to harder fruit compared to the S2 fruits. The microstructural study revealed parenchyma degradation during drying in both the outermost area (secondary epidermis) and internal flesh, and this process was faster in S1 than in S2. The second peel presented hollows, generated by water outflow, which were bigger in S1 and explained the faster internal dehydration in S1. During drying, slight browning occurred, as reflected in the declining color parameters (L*, h* and C*). Water removal led to soluble solids tannin reduction to non-astringency values on day 28.

Ginger rhizome (Zingiber officinale) is widely used as a spice or as a medicinal plant. The major bioactive compound in fresh ginger rhizome is 6-gingerol and it is known for having a number of physiological effects. This compound is heat-sensitive and during cooking or drying will transform into 6-shogaol. Hence, the 6- gingerol content is used to evaluate the quality of dried ginger. The content of 6-gingerol during drying was measured using HPLC. Several factors that could affect the 6-gingerol content were considered and a predictive model for changes in 6-gingerol has been developed from the experimental data. The predictive model includes a single term drying model that predicts the changes of moisture content during drying. Drying time and relative humidity (ranging from 10% to 40%) impacted 6-gingerol content whereas drying air temperature (ranging from 30°C to 60°C) had a lesser effect. It was also found that the 6-gingerol content in fresh rhizomes was highly variable and thus required thorough testing prior to drying to be able to make the prediction more accurate. [ABSTRACT FROM AUTHOR]

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The aim of this research was to evaluate the effect of different drying methods on industrially obtained lingonberry pulp juice by-products. For investigations, by-product was dried using hot air dryer (at temperatures 80 °C, 60 °C and 40 °C), microwave-vacuum dryer and freeze-dryer. The freshly defrosted by-product was used as control. All samples were analysed on the basis of their moisture content, colourimetric attributes (C1E L*a*b* colour system), content of vitamin C (iodometric method), content of total carotenes (TC), total phenol content (TPC). total anthocyanin content (TA) and antiradical activity (DPPH, ABTS+). The obtained data on content of vitamin C showed a 10% decrease between control and sample dried in hot air at 80 °C. Similar changes were noticed with total anthocyanin content, the lowest amount was also foiin in this sample (306.72 ± 18.32 mg 100 g-1 DW). Total carotenes content was higher in freeze-dried sample (5.61 ± 0.16 mg 100 g-1 DW) which was very close to control sample. A significant loss of total phenol content was noticed after drying, up to 80%, similar tendencies were noticed with changes of antiradical activity'. After evaluating the obtained data, the use of hot air dryer at 80 °C temperature resulted in the lowest amount of vitamin C and anthocyanins in lingonberry by-products, which makes this method unsuitable for drying byproducts of these berries. However, vacuum assisted microwave drying and freeze drying showed less dama 21112 impact on dried material. [ABSTRACT FROM AUTHOR]

Although N -acetylcysteine (NAC) has shown significant medical and antioxidant activities, its strong sour taste and sulfur odor limits its use in food. Here we spray dried and air dried a mixture of proteins and polysaccharides that served as matrix materials to entangle NAC and delay its release in water. Proteins including egg white, gelatin, whey protein isolate, and casein, were combined with polysaccharides such as hydroxypropyl methylcellulose, and carboxymethyl cellulose and electrostatic interactions with NAC were formed. The resulting solutions were then air or spray dried. The powders were analyzed by SEM, FTIR, LC-MS, NMR, and conductometry. The resulting powders exhibited slower release in water, particularly when polysaccharides were incorporated with proteins as matrix materials. SEM results showed the spray-dried samples displayed spherical and concaved structures with particle sizes ranging from 2 to 10 μm. While in the air-dried samples, NAC crystals were observed on the surface. Conductometry revealed that gelatin, with different bloom strengths exhibited different patterns in their NAC release profiles upon spray drying. In comparison to the spray-dried samples, samples obtained from air drying showed a faster NAC release in water. • Spray drying and air drying were used for N -acetylcysteine (NAC) encapsulation • Combinations of protein and polysaccharides were used as matrix materials • Addition of polysaccharides to gelatin improved the release profile of NAC • Spray-dried samples had slower NAC release in water than air-dried samples [ABSTRACT FROM AUTHOR]