Search Results (121)

The growing interest in isotonic drinks translates into the need to develop formulations based on natural raw materials, which limit the use of synthetic additives while simultaneously increasing the bioactive value and sensory appeal of the products. The aim of this study was to develop innovative formulations for isotonic drinks based on natural fruit juices and to evaluate their physicochemical properties and sensory acceptance. Formulations containing 10–15% (v/v) fruit juice, with the addition of salt (0.13 g/100 mL) and organic sugar, were prepared, taking care to maintain osmolality within the range of 270–330 mOsm/kg. The 10 most appealing variants were selected and subjected to sensory analysis using the QDA; physicochemical analyses, including the determination of total polyphenol content (TP) and the DPPH free radical scavenging capacity; and the measurement of color parameters in the CIE Lab system. All the drinks analyzed received positive ratings in the sensory test (average acceptability scores ranging from 6.9 to 8.1). Physicochemical analyses revealed that the drinks had significant antioxidant activity: polyphenol content ranged from 46 mg to nearly 170 mg GAE/100 mL, whilst DPPH free radical scavenging capacity ranged from 45% to nearly 90%. We found that the use of fruit juices makes it possible to create isotonic drinks which not only effectively rehydrate, but also provide valuable antioxidant compounds. Full article

Drought stress during early growth stages severely limits wheat productivity globally. Understanding varietal physiological responses to drought stress is critical for breeding climate-resilient cultivars. Two-week-old plants from two winter wheat (Triticum aestivum L.) cultivars—Katya (drought-tolerant) and Zora (drought-sensitive)—were subjected to drought for seven days, followed by rehydration. The experiments were conducted in pots in controlled conditions. The photosystem II (PSII) function was evaluated using chlorophyll a fluorescence (OJIP transients), thermoluminescence emissions and pigment content analysis. Under drought, Katya maintained functional PSII integrity with stable quantum efficiency and increased chlorophyll content, while Zora exhibited chlorophyll degradation. Fresh and dry weight declined in both genotypes but significantly only in Zora; recovery occurred after rehydration. Chlorophyll fluorescence revealed that varietal divergence was localized to the O–J phase of PSII photochemistry, indicating differences in reaction-center behavior confirmed by thermoluminescence. Katya demonstrated preserved PSII reaction-center density, balanced energy partitioning, homogeneous PSII populations, and superior recovery capacity. Conversely, Zora showed reaction-center depletion, elevated energy dissipation, impaired electron transport beyond Q_A, and persistent PSII heterogeneity even after rehydration. Drought tolerance in the studied genotypes was associated with the maintenance of PSII structural integrity, efficient photochemical function, and rapid recovery mechanisms. These physiological markers—particularly early PSII photochemistry kinetics and reaction-center stability—provide valuable selection criteria for breeding programs, targeting drought resilience under changing climate conditions. Full article

Food deterioration is largely driven by microbial activity, particularly by fungi producing mycotoxins exhibiting mutagenic and carcinogenic effects. Garlic (Allium sativum L.), valued for its antimicrobial and anti-inflammatory properties, is widely recognized as a natural food preservative; however, the high moisture content and intense respiration of freshly harvested garlic accelerate enzymatic degradation of its bioactive compounds, making post-harvest processing essential to preserve its functional properties. This study evaluated the preservative potential of convectively dried garlic (50–90 °C) by testing the antifungal activity of its extracts (6.3–0.8%) against Aspergillus parasiticus, while a modeling approach was employed to quantitatively describe this phenomenon. The antioxidant activity and rehydration capacity were also analyzed. The results demonstrated that both drying temperature and extract concentration significantly influenced fungal growth kinetics. The strongest inhibition was observed for extracts from raw garlic and garlic dried at 50 °C, whereas extracts from samples dried at 70–90 °C only partially suppressed the microbial activity. Predictive modeling accurately described fungal growth (MAE = 1.9, R² = 0.995), enabling its application in optimizing food preservation strategies. Antioxidant activity was highest in raw garlic, decreased significantly in garlic dried at 50 °C, and then increased progressively with rising drying temperature. The study highlights the need to maintain a balance in drying conditions that ensures efficient drying kinetics while preserving bioactive, functional, and antifungal properties. 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

Microwave pretreatment of native soybeans in the preparation of yuba remains underexplored, and the impact of this treatment on the resulting yuba quality is still unclear. In this study, soybeans were subjected to microwave pretreatment for 30–120 s before conventional soaking. CLSM revealed soybean microstructural changes, including cell-wall degradation and improved dispersion of proteins and lipids. FTIR and SDS-PAGE results of yuba indicated that hydrogen bond cleavage and the formation of new cross-links reduced protein coiling and polar group exposure, while stabilizing aliphatic chains, ultimately yielding a stronger and more compact yuba network structure. Mechanical and rehydration results further indicated that microwave treatment positively affected yuba quality. The 90 s pretreatment was identified as the optimal condition, exhibiting the highest elongation at break (126.36% increase) and rehydration capacity, along with improved color attributes, including higher lightness (L*) and yellowness (b*) values. These changes are likely attributable to disulfide-mediated protein reorganization, which creates greater spatial availability and thereby facilitates lipid incorporation. This study elucidates how microwave pretreatment drives the reorganization of soybean protein and lipid components, thereby influencing their distribution during film formation and providing a foundation for the tailored design of yuba with targeted mechanical properties. Full article

Apple pomace, a major by-product of juice processing, requires effective drying for valorization and preservation. This study investigated the thin-layer drying kinetics of apple pomace from three varieties (Starkrimson, Idared, and Jonagold) under forced convection at 57 °C, 63 °C, and 68 °C. Seven mathematical models were used to fit the experimental moisture ratio data and evaluated using statistical indicators (R², RMSE, χ², and MBE). In addition, the proximate composition, titratable acidity, water activity, color parameters, rehydration capacity, total phenolic content, antioxidant activity, and phenolic and organic acid profiles of the resulting apple pomace powders were assessed. Of the models tested, the Midilli–Kucuk model demonstrated superior performance with the highest R² (>0.99) and lowest RMSE and χ² values across all varieties and temperatures. The Page and Logarithmic models also showed good predictive capability. Significant differences in phenolic content and antioxidant activity were observed between powders from different apple varieties, with Starkrimson showing the highest values, followed by Jonagold and Idared. These findings provide essential kinetic parameters for optimizing apple pomace drying processes and support the development of value-added products from this abundant agro-industrial by-product. Full article

Calcium silicate hydrate (C(-A)-S-H) and its aluminosilicate counterpart (C-A-S-H) constitute the principal binding phases in Portland cement and blended systems, governing mechanical strength and durability. This paper presents a summary of the work related to dehydration of C(-A)-S-H and rehydration of dehydrated C(-A)-S-H. Their thermal dehydration, a key process for cement recycling, induces profound multi-scale transformations: at the atomic level, it alters calcium and aluminum coordination environments and disrupts chemical bonding; at the chain-structure level, it causes depolymerization of the silicate/aluminosilicate networks; and at the microstructural level, it leads to changes in nanoscale particle morphology, aggregation state, and pore structure, creating a metastable, defect-rich, high-energy state distinct from the original C(-A)-S-H. The subsequent rehydration of this dehydrated C(-A)-S-H, which is not a simple reversal but a distinct dissolution–precipitation process, enables microstructural reconstruction and restored reactivity upon contact with water. This rehydration capacity is fundamentally exploited in thermally activated recycled cement—a novel binder concept that leverages dehydration-induced metastability for renewed strength development. Understanding these interconnected processes, influenced by factors like temperature, humidity, rate, and aluminum content, is critical for advancing sustainable cement technology, enabling the design of high-performance recycled cement and concrete, and facilitating the recycling of cementitious materials. Full article

This study systematically investigated the effects of freeze-drying on chicken, pork, and beef by examining pH, moisture content, rehydration capacity, water distribution, color, and texture profile at 2, 4, 6, 8, and 11 h. The pH values of all meats remained relatively stable within 5.6–6.2 throughout the drying process. Moisture content followed a “rapid dehydration-slower drying-stabilization” pattern, with pork retaining higher moisture during the mid-drying phase, while chicken and beef lost water more rapidly. The rehydration capacity increased with prolonged drying, with chicken showing the highest rehydration efficiency. Color changes were species-dependent. Specifically, chicken initially brightened before slight darkening, beef lost lightness with a temporary increase in redness, and pork gradually yellowed. Texture profiles also varied, with chicken maintaining relative stability throughout the drying process, beef showing temporary mid-drying hardness, and pork experiencing rapid declines in springiness and cohesiveness alongside fluctuating hardness. These findings provide valuable insights for optimizing freeze-drying protocols to preserve quality, functional performance, and sensory characteristics across different meat types. Full article

Freeze-drying, also known as lyophilization, is a state-of-the-art method for preserving food, offering excellent retention properties for nutrients, structure, and taste compared to other drying processes. Freeze-drying yields a product visually similar to fresh produce. However, due to the high energy requirements and operational costs associated with the process, its broader use as an industrial tool is limited. This review encompasses the optimization of all key stages, including pretreatment, freezing, primary drying, secondary drying, and storage. Process efficiency and product quality depend on a variety of factors, including raw material composition, pretreatment strategies (e.g., Pulsed Electric Fields), chamber pressure, shelf temperature, and freezing rate. These parameters are critical control points for determining the final product outcome. Optimizing these parameters is essential; as summarized by recent research, lyophilization effectively protects bioactive compounds, color, flavor, and rehydration ability in various food systems, including fruits, vegetables, meats, seafood, and specialty products. To achieve broader industrial adoption, this gold-standard method requires advancements in process intensification and hybrid drying systems, potentially integrated with intelligent process control. These advances are crucial to enhancing the economic viability of freeze-dried products and maintaining their reputation as the gold standard in creating high-quality, shelf-stable food products. This review consolidates current knowledge into a coherent conceptual model. The model clarifies the deterministic sequence by which adjustable processing conditions direct essential physicochemical changes within the food matrix, thereby defining the product ultimate nutritional, sensory, and stability properties. Establishing this cause-and-effect framework provides a foundation for systematic process improvement and facilitates broader commercial implementation. Full article

Dill is a valuable herb recognized for its rich nutritional composition and bioactive properties. Drying is an efficient preservation technique for maintaining its quality characteristics and ensuring longer storage stability. Incorporating ultrasonic pretreatment before the drying process can significantly reduce energy consumption (SEC) and greenhouse gas emissions. To the best of our knowledge, this is the first study to comprehensively evaluate ultrasound-assisted hybrid microwave–convective drying of dill (Anethum graveolens L.) leaves, focusing on the combined effects on drying kinetics, energetic and exergetic performance, providing an indirect emission estimate and multiple quality attributes. This study aimed to evaluate the drying kinetics, energy and exergy performance parameters, greenhouse gas emissions, quality properties (water activity, rehydration ratio and color) and antioxidant capacity of dill leaves dried by the microwave–hot-air (MW-HA) technique combined with ultrasonic (US) pretreatment. The experiments were conducted at MW power levels of 20%, 40%, and 60% (corresponding to a total output of 900 W), air temperatures of 40 and 60 °C, and US pretreatment durations of 0, 10, and 30 min. The results illustrated that rising MW power, air temperature and US duration significantly reduced the drying time, SEC and greenhouse gas emissions. At higher process conditions, specifically, 40% MW power, 60 °C drying temperature, and 30 min US pretreatment, the maximum energy efficiency (10.17%) and exergy efficiency (11.35%) were obtained. In terms of quality attributes, the best results were achieved at 40% MW power, 60 °C air temperature, and 10 min ultrasonic pretreatment, with reduced water activity (0.258), minimal color variation (ΔE = 11.44), improved rehydration ratio (3.88), and high retention of antioxidant activity. These findings demonstrate the potential of ultrasound pretreatment to enhance drying performance by reducing energy use and emissions while improving quality and antioxidant retention in dill, offering new guidelines for sustainable processing of this herb. Future studies should optimize microwave–hot-air-drying conditions to balance energy efficiency, exergy, and product quality. Full article

Edible mushrooms (Suillus luteus) represent valuable sources of nutrients and bioactive compounds that are sensitive to drying conditions. The objective of this study was to determine the drying time, kinetic model, effective diffusivity, activation energy, and color changes in S. luteus samples subjected to convective and vacuum drying at 70 and 50 °C, respectively, following pretreatments with 1% citric acid or blahing. The shortest drying time to reach equilibrium moisture was 14 h at 70 °C under a vacuum, whereas the longest was 44 h at 50 °C under convective drying. The Midilli, logarithmic, and Henderson and Pabis models provided the best fits for vacuum drying. The effective moisture diffusivity values ranged from 5.83 × 10⁻⁹ m²s⁻¹ at 50 °C to 1.159 × 10⁻⁸ m²s⁻¹ at 70 °C, while the mean activation energies for vacuum and convective drying were 10.27 kJmol⁻¹ and 24.7 kJmol⁻¹, respectively. The highest rehydration capacity was observed in untreated samples dried under a vacuum, with a value of 3.5 g H₂O/g dry matter, whereas convective drying yielded 2.4 g H₂O/g dry matter. The greatest shrinkage with respect to thickness was observed in those treated with citric acid and blanching. Correlation analysis of color revealed a strong negative relationship between lightness (L*) and total color difference (ΔE), as well as high positive correlations among a*, b*, and C*, suggesting that color transformations occur jointly throughout dehydration. The findings indicate that effective diffusivity increased with temperature, untreated samples exhibited greater water loss, and rehydration ratios were higher in untreated compared with pretreated samples. Full article

Melatonin is recognised as a multifunctional regulatory molecule that enhances plant tolerance to abiotic stresses, but its effectiveness is often strongly genotype-dependent. This study aimed to elucidate how exogenous melatonin (200 µM) modulates the physiological and biochemical responses of wheat during drought and subsequent recovery in two genotypes with contrasting grain pigmentation: the standard cv. Bohemia (red grain) and an experimental purple-pericarp (PP) line. Plants were exposed to drought at the early vegetative stage (BBCH 15), and gas exchange, leaf water potential, and biochemical markers (proline, malondialdehyde, phenolics, and flavonoids) were assessed during drought and after rehydration. In cv. Bohemia, water deficit led to a pronounced decrease in CO₂ assimilation, stomatal conductance, and leaf water potential, accompanied by strong increases in proline (Pro) and malondialdehyde (MDA). Melatonin application in this genotype markedly reduced the accumulation of Pro and MDA and accelerated the recovery of gas exchange, indicating a significant protective effect. The lower Pro levels in melatonin-treated Bohemia plants suggest that melatonin mitigated the perceived stress intensity, thereby reducing the physiological demand for osmotic adjustment. In contrast, the PP line exhibited higher inherent stability of the photosynthetic apparatus and more moderate biochemical shifts; its recovery was almost complete and independent of melatonin. Overall, these results indicate that the functional benefit of exogenous melatonin is greater in genotypes with a lower intrinsic stress-buffering capacity. This study highlights the importance of considering constitutive genotype traits and the recovery phase when using physiological regulators to improve wheat drought resilience. Full article

The poor rehydration capacity of micellar casein (MC) powder due to the tightly cross-linked structure formed by colloidal calcium phosphate (CCP) limits its potential applications. This study aimed to improve the rehydration properties of MC powder by electrodialysis (ED) treatment. After being treated by ED for 0, 10, 30, 60, and 90 min, the casein micelle powder exhibited a reduction in calcium content (25.55 ± 0.08 g/kg to 17.47 ± 0.05 g/kg) with prolonged treatment, corresponding to the progressive dissociation of CCP bridges. Furthermore, the ED treatment significantly increased the solubility of casein micelle powder. Interestingly, after 60 min, the solubility of ED-treated micellar casein plateaued at approximately 80% within 30 min, likely due to modification on protein structure. Therefore, these results indicate that the structure of micellar casein can be modified through ED treatment, leading to improved rehydration properties. Full article

This study evaluated the physiological and biochemical responses of three Eucalyptus genotypes (E. urophylla; hybrid E. urophylla × E. grandis; hybrid E. urophylla × E. camaldulensis) under three water regimes (well-watered—plants watered daily with 70% of field capacity; rehydrated—water supply suspended at initial wilting symptoms; water deficit—water supply suspended upon reaching 50% of soil water retention capacity) in a warm tropical environment. The treatment was performed through daily weighing of plant pots and addition of the required water amount to reach the pot weight in each treatment. Measurements included stomatal conductance (gs), carbon assimilation rate (A), transpiration rate (E), leaf water potential (Ψ_leaf), chlorophyll content (a and b), proline accumulation, and the activities of superoxide dismutase (SOD) and catalase (CAT). The genotypes exhibited contrasting drought responses: E. urophylla × E. camaldulensis showed the highest resilience, maintaining gas exchange, water status, and proline accumulation under stress. E. urophylla × E. grandis displayed intermediate tolerance, while E. urophylla was the most sensitive. Overall, drought tolerance in Eucalyptus emerged from the coordinated interaction of hydraulic, osmotic, and antioxidant mechanisms. Full article

The pursuit of efficient drying methods that preserve fruit quality remains a major challenge in food processing. Non-thermal pre-treatments such as ultrasonication (U), edible film coating (F), and osmotic dehydration (O) can improve drying performance but show limited effectiveness when applied individually. This study investigates a combined pre-treatment strategy for pear drying, evaluating a taro starch-based edible coating used alone and in combination with U and O. Pear slices received individual and combined pre-treatments (F, OF, UF, and UOF) prior to drying at temperatures of 60, 70, and 80 °C. The drying kinetics were modeled, and quality parameters such as effective moisture diffusivity (D_eff), rehydration capacity, microstructure, color, total phenolic content (TPC), antioxidant activity, and vitamin C, were assessed. The Page model fitted the drying data the best (R² > 0.9935). UF achieved the shortest drying time and a porous microstructure, thereby enhancing rehydration. OF showed the highest D_eff and best color retention, but the lowest rehydration. Conversely, UOF caused the greatest losses in bioactive compounds (TPC: 54.29 mg GAE/100 g; antioxidant activity: 15.39%; 0.48 mg vitamin C/100 g). Unlike single-technology studies, this sequential pre-treatment strategy for pears uniquely tailors the final quality, targeting efficiency, color, bioactivity, or structural properties. Full article