Search Results (613)

Background/Objectives: Citrus peels are widely utilized as functional ingredients in health foods; however, their functional value is often assumed based on botanical classification rather than verified chemical composition. Bushukan (Citrus medica var. sarcodactylis) was selected as it lacks developed edible pulp; consequently, the usable portion consists almost entirely of peel tissue, making it a suitable model for evaluating peel-specific functional components. This commentary highlights the importance of species- and origin-specific evaluation through a case study of Bushukan (Citrus medica var. sarcodactylis) whole fruit powder cultivated in Japan. Methods: Dried whole-fruit powder samples of bushukan, prepared by freeze-drying and hot-air drying at 50 °C, were analyzed, and the contents of hesperidin and nobiletin were quantified using high-performance liquid chromatography (HPLC) following methanol reflux extraction. Results: Hesperidin was detected at 75 mg/100 g under both drying conditions, whereas nobiletin was below the practical limit of quantification (approximately 1 mg/100 g). No reduction in hesperidin content was observed after drying at 50 °C. These levels were markedly lower than those reported for commonly used citrus peels, such as satsuma mandarin, in previous studies. Conclusions: This commentary demonstrates that Japanese-grown bushukan samples do not necessarily provide substantial levels of commonly expected citrus flavonoids. These findings underscore the need for species- and origin-specific compositional verification before the use of citrus peels as raw materials for health food applications, illustrating this need through a practical, cautionary case study. Full article

This study systematically investigated the combined effects of drying method (mid- and short-wave infrared drying, MSID; hot air drying, HAD; radio frequency-hot air combined drying, RF-HAD), drying temperature (35, 45, 55, 60 °C), and initial wet-basis moisture content (20%, 25%, 30%) on drying characteristics, nutritional quality, texture, and oxidative stability of peanuts. RF-HAD achieved the shortest drying time, followed by MSID and HAD. Protein content remained stable across all treatments. Fat, oleic acid, and total amino acids were significantly affected by all three factors with significant two-way interactions; linoleic acid exhibited significant method × moisture and three-way interactions. Hardness, adhesiveness, springiness, gumminess, and chewiness showed significant three-way interactions, indicating interdependent effects. All samples met national standards for acid value and peroxide value. MSID yielded the lowest acid value and peroxide value immediately after drying, suggesting better initial oxidative quality. Acid value was primarily influenced by method and temperature, with significant two-way interactions, whereas peroxide value showed significant main effects and a highly significant three-way interaction. No single drying condition optimized all quality attributes. RF-HAD excels in drying efficiency and texture enhancement but requires temperature control to limit oxidation; MSID offers superior initial oxidative stability and amino acid retention. Initial moisture content acts as an active variable that modulates the effects of drying method and temperature. Full article

This study aimed to comparatively optimize and evaluate the quality characteristics of Washington Navel orange slices using vacuum microwave drying (VMD) and conventional hot air drying (HAD) systems. Response Surface Methodology based on the Box–Behnken design was applied to both systems. For the models developed in the VMD system, the coefficient of determination (R²) was found to be in the range of 0.96–0.97, and the optimum conditions were determined as 4 kW power, 60 °C temperature, and 2 mm slice thickness. For HAD, the optimum conditions were determined as 78 °C temperature, 1.57 m/s air velocity, of 2.3 mm slice thickness. VMD showed superior performance compared to hot air drying in terms of total phenolic preservation, retention of bioactive compounds, and rehydration capacity. Hydroxymethylfurfural (HMF) formation was higher during hot-air drying. The effective moisture diffusivity (D_eff) was significantly higher in VMD (8.38 × 10⁻¹⁰ m²/s) than in HAD (1.49 × 10⁻¹⁰ m²/s), indicating enhanced internal moisture transport under vacuum microwave conditions. The results revealed that VMD is an efficient technology for producing high-quality dried citrus products with improved bioactive retention and reduced processing time. Full article

Flammulina velutipes (Golden Needle Mushroom, F. velutipes) undergoes rapid postharvest deterioration characterized by browning and decay. Drying effectively extends its shelf life and processing window. This study systematically compared the quality attributes and metabolic profiles of F. velutipes subjected to different treatments: fresh F. velutipes as the control group (CK), hot-air drying (HAD), vacuum freeze drying (VFD), and natural air drying (NAD), to elucidate the underlying mechanisms of drying-induced changes. In appearance, VFD samples were uniformly bright with shape well maintained, while HAD and NAD were brownish yellow with significantly reduced volume. In terms of antioxidant capacity, VFD demonstrated the highest level, followed by HAD. A total of 2645 metabolites were identified in dried F. velutipes via metabolomics (positive/negative ion modes), primarily comprising lipids, terpenoids, polyphenols, amino acids, carbohydrates, and steroids. In contrast to VFD, both HAD and NAD showed reduced levels of certain metabolites. VFD treatment yielded the richest profile of differential metabolites in F. velutipes. These results position VFD as the superior method for preserving the quality and metabolic integrity in F. velutipes. This comparative study serves as a practical reference for selecting the most suitable drying method in the F. velutipes industry and enhances our understanding of the metabolic responses to dehydration stress. Full article

Industrial processing of apple to obtain products like juice or cider generates a significant amount of pomace, which represents 25–30% of the fresh fruit mass. Different technologies are needed to valorize apple pomace (AP), considering its significant amount of high-value compounds, such as fiber, vitamins, and polyphenols. Hot-air convection (CA) and infrared (IR) drying are widely used methods for preserving polyphenols from by-products, such as apple pomace (AP), while also extending their shelf life. This study aimed to evaluate the influence of CA and IR drying on drying kinetics, color parameters, and the preservation of polyphenolic compounds, as well as to identify a sustainable extraction approach. Both drying methods significantly affected the color characteristics and content of polyphenols with high antioxidant activity. A significant impact was noticed at higher temperatures, which may be associated with the partial inactivation of browning enzymes. IR drying resulted in a shorter drying time and lower specific energy consumption compared to CA. Furthermore, the assessment of solvent efficiency in ultrasound-assisted extraction (UAE) indicated that the natural deep eutectic solvent (NaDES) composed of choline chloride and glycerol (1:1 molar ratio) provided superior recovery of phenolic compounds with high antioxidant activity compared to conventional solvents and the other NaDES analyzed. Optimization of UAE conditions using this polyol-based NaDES allowed for achieving an extract characterized by a polyphenolic profile dominated by flavan-3-ols (catechin and epigallocatechin), followed by phenolic acids, mainly chlorogenic acid. These results confirm the potential of AP as a valuable source of bioactive compounds and of polyol-based NaDESs as a sustainable and efficient alternative for their recovery. Full article

Hot-air drying is widely adopted for herbs because it is robust and easy to control, yet it is often energy-intensive and may operate far from optimal conditions when industrial dryers rely on fixed airflow paths and large air recirculation rates. This work investigates a conventional basket-type, adiabatic hot-air dryer through an instrumented 30 h drying campaign and a psychrometric energy analysis. The hot-air drier is designed to reduce the relative humidity of herbs from the environmental value (highly variable as a function of the species, the weather conditions, and, mostly, the seasonality) to 20%. Temperature and relative humidity were measured at four positions to characterize the shelf-by-shelf drying sequence and to identify process phases. A mass balance indicated that approximately 3.8 t of water was removed during the trial. Based on the measured thermodynamic states of the moist air and estimated airflow rates (35,000–53,000 m³/h), the baseline configuration was analyzed and an upgrade strategy was proposed to improve dehumidification and overall efficiency while preserving the conventional hot-air-drying concept. The alternative solution integrates a refrigeration-based dehumidification loop (heat pump) to decouple moisture removal from sensible heating; three plant layouts and seasonal boundary conditions (summer/winter) were simulated. For the most favorable configurations, the specific final–primary energy demand and the associated CO₂-equivalent emissions were reduced by about 70–85% compared with the baseline, depending on the airflow rate and recirculation strategy. The results highlight practical retrofit options for existing herb dryers and provide a transparent framework for translating measured psychrometric states into energy and emission indicators. The results, achieved and discussed in this study, were used to optimize the utilization of an already existing and operative hot-air dryer. Based on the proposed working configuration, the dryer now allows achieving the fixed target for herb mixtures of the previous configuration and, at the same time, reducing the energy consumption and associated equivalent CO₂ emitted, as well as achieving process completion in less time. Full article

Municipal sewage sludge is an environmental liability but also an energy-rich biomass that can support circular economy resource recovery. Here, we benchmark thin-layer drying of dewatered municipal sewage sludge (sludge cake) (40 g; layer thickness ≤ 5 mm) under open-air, convective hot air (40–150 °C), and microwave (70–1200 W) conditions to quantify drying kinetics, hygienisation indicators, and a screening-level energy-use proxy. High-power microwave drying reduced the time to constant mass from 32 h (open air) and 25 h 05 min (40 °C convection) to 20 min (900 W) and 14 min 05 s (1200 W). Faecal indicators (total/thermotolerant coliforms and presumptive Escherichia coli) were below detection after ≥100 °C convection or ≥300 W microwave treatment, while mesophilic aerobes and sulfite-reducing Clostridium spp. decreased by ~3–4 log10 with increasing exposure. A dragonfly-optimised ε-support vector regression model (DA–SVR) predicted drying trajectories across modes (overall RMSE ≈ 0.79 percentage points; held-out RMSE ≈ 1.47; R² ≥ 0.99). Overall, microwave thin-layer drying coupled with DA–SVR decision support enables constraint-based screening of sewage–sludge conditioning windows for logistics and thermal valorisation pathways; the framework can be extended to incorporate additional analytical endpoints where available. Full article

Processing rosehips generates substantial solid waste that retains valuable bioactive compounds. This study evaluated the effects of different treatments on the composition, phenolic and flavonoid contents, and antioxidant capacity of powders derived from rosehip waste. Rosehips were processed into purée by cold screw pressing or boiling, yielding raw and boiled processing waste fractions (RW and BW). These fractions were then dehydrated by hot-air drying or lyophilisation to obtain RWd, RWl, BWd, and BWl. Additionally, a previous cold screw pressing step was applied to the boiled processing waste, producing BWpd and BWpl. Cold screw pressing increased phenolic and flavonoid levels and enhanced the antioxidant capacity of the resulting waste compared with traditional boiling. The lyophilised powder derived from raw processing waste exhibited the highest total phenolic content (TPC, 27.16 mg GAE/g), total flavonoid content (TFC, 20.35 mg QUE/g), and Trolox equivalent antioxidant capacity by ABTS and DPPH (TEAC-ABTS, 89.13 µmol TE/g; TEAC-DPPH, 163.99 µmol TE/g), although at higher processing costs. As hot-air drying achieved comparable levels for TPC (20.01 mg GAE/g), TFC (19.53 mg QUE/g), TEAC-ABTS (58.01 µmol TE/g), and TEAC-DPPH (150.01 µmol TE/g), it may represent a more economical alternative to lyophilisation. These findings demonstrate the potential of rosehip-processing waste as a sustainable raw material for the development of functional food ingredients. Full article

Background: Lycium barbarum L. is gaining significant interest as a medicinal and culinary raw material. The quality and aroma are significantly influenced by metabolite accumulation, which differs based on origins and drying methods. Methods: This study utilizes gas chromatography–mass spectrometry (GC-MS) to analyze the metabolic profiles of the ‘Ningqi’ No. 1 variety from three distinct origins employing two drying techniques (natural sun drying, NSD; hot-air drying, HAD). The samples include Zhongping, Ningxia, with HAD (1-1); Zhongning, Ningxia, with NSD (1-2); Wuwei, Gansu, with NSD (1-3); Nuomuhong, Qinghai, with NSD (1-4); and Nuomuhong, Qinghai, with HAD (1-5). Results: The study found that aldehydes, esters, ketones and alcohol are key secondary metabolites generated during NSD and HAD treatments of goji berry from various regions. Flavor analysis revealed the compound Ethanol, 2-phenoxy- (balsamic) was up accumulated in goji berry from Qinghai drying with NSD compared with HAD; goji berry drying with HAD collected from Ningxia compared with Qinghai; goji berry drying with NSD collected from Gansu compared with Ningxia; and goji berry drying with NSD collected from Qinghai compared with Ningxia. The compound 2-Thiophenemethanol (burnt) was up accumulated in goji berry drying with HAD collected from Ningxia compared with Qinghai. Further flavor analysis revealed that the compound Undecanal (floral) was up accumulated in goji berry drying with NSD collected from Qinghai compared with Ningxia and Gansu. 1H-Pyrrole-2-carboxaldehyde (burnt), 1-ethyl- (burnt) was up accumulated in goji berry drying with NSD collected from Qinghai compared with Gansu. KEGG enrichment analysis suggests that ‘Arginine and proline metabolism’ could be the primary metabolic pathway in the goji berry drying process. Conclusions: This study examined how origins and drying methods affected the metabolites and metabolic pathways of goji berries to elucidate the mechanisms impacting their quality and flavor. The findings provide important insights into the use of goji berries in functional foods and pharmaceuticals. Full article

Coal slime, typically with particle sizes below 1 mm, is difficult to utilize directly and is frequently associated with energy loss and environmental burden. This study comparatively investigates hot–air drying and transient steam flash drying for the dehydration and upgrading of filter–pressed coal slime. In hot–air drying, elevated temperature and reduced particle size markedly accelerate the drying rate, and the apparent activation energy ranges from 18.39 to 20.96 kJ·mol⁻¹ for different particle sizes. For steam flash drying, the influences of steam pressure, particle size, and holding time on moisture–removal efficiency and physicochemical structure are evaluated. The dehydration performance is enhanced by higher steam pressure and larger particle size, reducing the moisture content of the coal slime from 38% to 20%, with approximately 80% of the total water removed during the transient depressurization stage. Structural analyses reveal partial decomposition of oxygen–containing functional groups and mesopore contraction after flash treatment. Compared with hot–air drying, steam flash drying achieves shorter processing time and lower specific energy consumption. These findings indicate that steam flash drying is governed by a pressure–induced phase transition and enhanced thermodynamic driving force, providing an intensified pathway for the efficient upgrading of high–moisture coal slime. Full article

Radish leaves are a nutrient-rich yet underutilized byproduct containing abundant fiber, minerals, and phytochemicals; however, their quality is highly affected by drying methods. This study systematically investigated the effects of three drying methods—hot-air drying (HD), microwave drying (MD), and freeze-vacuum drying (FD)—on the nutritional components, bioactive substances, and volatile compounds of radish leaves. A comparative analysis was conducted on their proximate composition, amino acid profiles, mineral contents, antioxidant capacities, glucosinolate profiles, and volatile profiles. Among the three methods, FD exhibited superior preservation of proteins, lipids, minerals (K, Mg, P, Fe, Zn, and Mn), and bioactive components, including polyphenols, flavonoids, glucosinolates, and vitamin C. In contrast, HD and MD led to significant reductions in these nutrients and bioactive compounds. A total of 33 glucosinolates and 779 volatile compounds, including 164 odor-active compounds, were identified collectively across the three treatments. The FD-treated samples exhibited distinct glucosinolate and volatile profiles, whereas HD- and MD-treated samples showed greater similarity. Multivariate analysis further revealed 12 key differential glucosinolates and 27 differential odor-active compounds among the three groups. This study provides a scientific basis for optimizing drying strategies to improve the nutritional quality and flavor characteristics of processed radish leaves. Full article

Background/Objectives: Insect oils have gained attention as sustainable cosmetic ingredients due to their bioactive lipid content. This study aimed to characterize oils from cricket and to evaluate their safety, biological activities, and performance in sunscreen formulations. Methods: Oils were extracted from Gryllus bimaculatus, Teleogryllus mitratus, and Acheta domesticus by cold pressing following hot-air drying. Fatty acid composition was determined using gas chromatography–mass spectrometry. Safety was assessed by cytotoxicity testing in normal human dermal fibroblasts (NHDF) and the hen’s egg chorioallantoic membrane (HET-CAM) assay. Antioxidant and anti-inflammatory activities were evaluated by intracellular reactive oxygen species (ROS) and nitric oxide (NO^•) assays. Based on biological performance, T. mitratus oil (TMO) was incorporated into sunscreen creams containing physical and chemical ultraviolet (UV) filters. Physical stability, viscosity, pH, sun protection factor (SPF), persistent pigment darkening/ultraviolet A protection factor (PPD/UVA-PF), and blue light protection were evaluated. Results: All cricket oils were non-cytotoxic to NHDF cells and were classified as non-irritating in the HET-CAM assay. TMO exhibited the strongest antioxidant activity, reducing intracellular ROS and significantly inhibiting NO^• production in lipopolysaccharide-stimulated cells. Only TMO showed measurable UVA protection (PPD/UVA-PF = 12.1, PA+++). Sunscreen creams formulated with TMO achieved higher photoprotective efficacy than olive oil-based creams, with SPF values up to 40.51 and PPD/UVA-PF up to 39.17. The inclusion of foundation pigments further increased SPF to 43.09 and enhanced blue light protection to 35.1%. Conclusions: TMO is a safe and effective multifunctional ingredient that enhances sunscreen performance and supports sustainable cosmetic formulation. Full article

Extant birds and the earliest dinosaurs may share fundamental metabolic features essential for aerobic exercise, suggesting that the extraordinary physical performance typical of avian species originated when dinosaurs first appeared during the Carnian Pluvial Episode (CPE). This physiological adaptation is complemented by hyperactive mitochondria that exhibit high oxygen consumption and low reactive oxygen species production. Molecular genomics of fossils, the so-called “Jurassic Genome,” indicates that these early dinosaurs possessed compact genomes, 50–60% the size of the human genome, and small cells, implying a highly stringent metabolic regime. We suggest that hyperactive mitochondria, closely associated with compact genomes and small cells, drive theropod adaptation to the hot, dry, and hypoxic environments of the Late Triassic period, ultimately enabling their ecological dominance. Early dinosaurs such as Herrerasaurus are hypothesized to have possessed advanced physiological traits shared with modern birds, including hyperactive mitochondria, compact genomes, small cells, and a developing air-sac system. Collectively, these features most likely may have contributed to exceptional metabolic capacity, locomotor performance, and adaptation to the harsh environment of the CPE. Full article

A low-temperature tempering staged drying process was proposed in this study to minimize quality degradation and improve drying efficiency during waxy corn drying. Experiments of continuous drying, low-temperature tempering drying, and low-temperature tempering staged drying were conducted to investigate the drying characteristics and quality of waxy corn. The results showed that the low-temperature tempering drying process could shorten the effective drying time and increase the drying rate during the latter stage of the drying process. Under the same hot air temperature, increasing the tempering temperature from 30 °C to 40 °C reduced the effective drying time by 20 min. The Modified Henderson and Pabis model exhibited the best fit to the experimental drying data (R² ≥ 0.9864). The microstructural images of the waxy corn flour showed no significant changes among the experimental groups. The color difference (ΔE) of the continuous drying group was higher than that of the other experimental groups. Both the low-temperature tempering drying process and the low-temperature tempering staged drying process caused less damage to the waxy corn with a relatively lower crack ratio, thereby leading to a reduced electrical conductivity value. The starch content of the 80 °C–60 °C–40 °C group was higher than that of the other experimental groups. Based on comprehensive evaluation of the drying characteristics, the color parameters, and the quality of the dried waxy corn, the 80 °C–60 °C–40 °C group represents a favorable alternative. Full article

Hot air drying is widely used in edible mushroom processing, but often leads to quality changes, including browning and flavor changes. This study focused on Phallus impudicus (P. impudicus), combining dynamic monitoring of browning-related indicators with lipidomics technology to systematically investigate the mechanism by which lipid changes influence quality during hot air drying. The results showed that drying significantly altered lipid metabolism. Encompassing 28 subclasses, five major lipid categories were identified: glycerophospholipids (GP), glycolipids (GL), sphingolipids (SP), isoprenylglycolipids (PR), and fatty acids (FA). From among these, the total content of GP remained the highest and increased significantly after drying, whereas the contents of GL and FA decreased markedly. Hydrolysis of structural lipids led to the collapse of cellular structure, and the levels of hydrolyzed lipids phosphatidic acid (PA), lysophosphatidylcholine (LPC), lysophosphatidylethanolamine (LPE), and lysophosphatidic acid (LPA) increased significantly after drying, which may adversely affect long-term storage. Furthermore, increased lipid unsaturation intensified browning, and lipid oxidation also promoted the formation of volatile flavor compounds. Overall, this lipidomic research demonstrated that hot air drying determines the final quality and flavor profile of dried P. impudicus through coordinated mechanisms involving membrane lipid oxidation, structural membrane damage, browning, and flavor generation. These findings provided a new insight into the mechanism of quality changes and a theoretical basis for quality improvement and process regulation for dried edible mushroom products. Full article