Search Results (145)

The agri-food sector faces the challenge of valorizing by-products and reducing waste. The frozen pumpkin industry generates substantial amounts of by-products rich in nutritional value, especially β-carotene. This study evaluates the nutritional and physical impact of incorporating pumpkin pulp flour (dehydrated and freeze-dried) obtained from by-products into cracker formulation. Crackers were prepared by replacing 10% and 20% of wheat flour with pumpkin flour, assessing the effects based on drying method. Physical parameters (expansion, color, and texture parameters) were measured, in the dough and in the baked products. Furthermore, β-carotene content was analyzed by HPLC-DAD, antioxidant capacity was measured with DPPH, ABTS, and ORAC, and total phenolic content was evaluated with the Folin–Ciocalteu method. Proximate composition and mineral content were also analyzed. Additionally, a preliminary sensory evaluation was conducted with 50 untrained consumer judges to assess acceptability of external appearance, texture, and taste. The inclusion of pumpkin flour significantly increased β-carotene content (up to 2.36 mg/100 g), total phenolics, and antioxidant activity of the baked crackers. Proximate analysis showed a marked improvement in fiber content and a slight reduction in energy value compared to wheat flour. Mineral analysis revealed that pumpkin flours exhibited significantly higher levels of K, Ca, Mg, and P, with improved but not always statistically significant retention in the final crackers. Freeze-dried flour retained more bioactive compounds and enhanced color. However, it also increased cracker hardness, particularly with dehydrated flour. Only the 10% freeze-dried formulation showed mechanical properties similar to those of the control. Sensory analysis indicated that all formulations were positively accepted, with the 10% freeze-dried sample showing the best balance in consumer preference across all evaluated attributes. Frozen pumpkin by-products can be effectively valorized through their incorporation into bakery products such as crackers, enhancing their nutritional and functional profile. Freeze-drying better preserves antioxidants and β-carotene, while a 10% substitution offers a balance between nutritional enrichment and technological performance and sensory acceptability. Full article

Dehydration and storage conditions used to preserve dairy cultures in the industry may negatively impact their viability and functionality. This study investigated the effects of freeze-drying and storage on the metabolic activity of Lacticaseibacillus rhamnosus 73 (L73). The strain’s viability after freeze-drying and storage, its metabolic activity in cultured milk, and its performance as a ripening agent in miniature cheeses were evaluated. Neither the freeze-drying process nor the storage conditions negatively affected its viability, as L73 maintained its initially high levels (>10 log cfu mL⁻¹) throughout the storage period. L73 improved the overall quality of the cheeses, as a reduction in hydrophobic peptides (i.e., potential bitter peptides) was evidenced in cheese manufactured with L73. Furthermore, L73 exhibited protective properties, as evidenced by the decreased availability of compounds that could be used as energy sources by adventitious microorganisms (e.g., galactose, hippuric acid) and the increased production of lactic acid in both cultured milk and cheese. Full article

In this study, cellulose nanocrystals (CNCs) were successfully isolated through the acid hydrolysis of freeze-dried and oven-dried bacterial nanocellulose (BNC) recovered from the floating pellicle generated during Kombucha tea production. The influence of the BNC drying method and its concentration on the yield and main characteristics of the CNCs obtained were studied. Additionally, selected CNC suspensions at various pH levels were subjected to freeze-drying and oven-drying, followed by an assessment of their dispersibility in water after undergoing different mechanical treatments. Results demonstrate the potential of utilizing byproducts from the expanding Kombucha industry as an alternative cellulose source for CNC production. Furthermore, the drying method applied to the BNC and its initial concentration in the hydrolysis medium were found to significantly impact the properties of the resulting CNCs, which exhibited diverse size distributions and Z-potential values. Finally, the redispersion studies highlighted the beneficial effect of drying CNCs from neutral and alkaline dispersions, as well as the requirement of ultrasound treatments to achieve the proper dispersion of dehydrated CNC powders. Full article

This study evaluated the combined effects of freeze–thaw and osmotic dehydration (OD) pretreatments on the physicochemical, functional, and sensory qualities of umbu slices. Fresh and thawed umbu slices (thawed at 26 ± 3 °C for approximately 1 h after being frozen for at least 8 days) were submitted to OD or directly processed. All slices were then dehydrated by convective drying. Treatments varied by drying temperature (50 and 60 °C) and sucrose concentration (40, 50, and 60 °Brix), resulting in sixteen conditions, including four without OD. Freeze–thaw pretreatment significantly enhanced sucrose uptake (24.11–49.89%) during OD, affecting the slices’ physicochemical and functional attributes. It also improved appearance, color, and texture, leading to a higher sensory acceptance. Among OD treatments, experiment 2 (non-pre-frozen, 50 °Brix at 50 °C) exhibited the highest total phenolics (71.95 mg/100 g) and lowest phenolic losses during in vitro digestion. Experiment 1 showed the highest flavonoids (3.94 mg/100 g), anthocyanins (0.62 mg/100 g), and chlorophylls (0.78 mg/100 g). Phenolic bioaccessibility ranged from 10.88% (experiment 14) to 52,90% (experiment 16). Experiment 13 (pre-frozen, 40 °Brix at 60 °C) had the highest antioxidant activity among freeze–thawed samples and was notable for its greater perceived sweetness. Therefore, frozen storage combined with osmoconvective dehydration is a promising strategy for conserving and adding value to umbu fruit. Full article

Experiences in the production, transportation and preparation of crude oil for transportation have shown that specific problems arise related to their mixing, including water contamination. In recent years, interest in studying these problems has significantly increased, mainly due to the development of extraction technologies for heavy oil samples and bitumen. Along with various difficulties encountered during the pipeline transportation of complex rheological crude oil blended with each other and with light oil, including condensate (such as sedimentation, etc.), imbalances are also observed during storage, as well as in the processes of delivery and reception. During the dehydration of oil mixtures, a synergistic effect is observed in the consumption of demulsifier. The article investigates, in accordance with international standards and based on laboratory tests, how the physico-chemical properties (density, viscosity, freezing point, saturated vapor pressure, chemical composition) of mixtures formed by blending various grades and compositions of Azerbaijani oil examples with each other and with condensate change and how the efficiency of dehydration of oil mixtures is affected by the mixing ratio of the oil involved. It was found that the quality indicators (physico-chemical parameters) of oil mixtures differ non-additively from the initial parameters of the blended products and in some cases, this difference is even observed with anomalies. Moreover, depending on the mixing ratio of the oil, variations in the consumption of demulsifier were also identified. Full article

The seasonality of Diospyros kaki limits its consumption, making it increasingly necessary to develop products that allow it to be available all year round. Therefore, the aim of this study was to optimize the osmotic dehydration process and to evaluate the changes in the physico-chemical, bioactive and volatile composition of persimmon subjected to drying. A central composite rotatable design was used with the independent variables as sucrose concentration (%) and immersion time (min). The desirability function for sucrose solution concentration and immersion time was 29.5% for 60 min for hot air oven drying and 38% for 29 min for freeze drying. The dehydrated fruit treated with osmotic pretreatment showed better responses in the quantification of bioactive compounds and retention of volatile compounds. Compounds such as nonanal and 6-methyl-5-hepten-2-one were identified in all the dehydrated products and the OD had a positive influence on their retention, especially for the lyophilized samples. Thus, it is clear that osmotic pretreatment is an ally in protecting the physico-chemical and chemical characteristics of the fruit when it undergoes a drying process, especially with regard to bioactive and volatile compounds. Full article

Background/Objectives: COVID-19 infection continues globally, with frequent emergence of unfamiliar SARS-CoV-2 variants acting to impair immunity. The competitive binding of SARS-CoV-2 spike proteins and angiotensin-converting enzyme 2 (ACE-2) can decrease the binding of the virus on native ACE-2 receptors on healthy human cells. It remains a practical approach to lessen viral spread. In this study, a method to encapsulate ACE-2 in the form of chitosan/tripolyphosphate cross-linked nanoparticles (NPs) was developed with emphasis placed on the best dehydration method to secure functional ACE-2 nanoparticles. Methods: Methods: Preparation conditions were assessed by varying pH (4.0–6.5) and the ratio between chitosan and ACE-2 mixing ratios (1:1, 1.5:1, 2:1, 2.5:1, and 3:1). The formulated NPs were then dehydrated using different approaches that included spray-drying (SD), freeze-drying (FD), and spray-freeze drying (SFD) and used varying mannitol concentrations (0, 1:1, and 5:1 of total weight). The mannitol was served as a cryoprotectant in this study. Results: The best formulation achieved used a pH 5.5 with a mixing chitosan–ACE-2 ratio of 2:1, where ACE-2-loaded NPs had an average particle size of 303.7 nm, polydispersity index (PDI) of 0.21, encapsulation efficiency (EE) of 98.4%, and ACE-2 loading content (LC) of 28.4%. After reconstitution, all SD samples had a relatively low yield rate, but the ACE-2 NPs dehydrated specifically using SFD required a lower amount of added mannitol (1:1 of its total weight) and produced a higher yield rate (p < 0.05) and similar PDI and EE values, along with relatively good particle size and LC. This formulation also produced a high ACE-2 release and uptake in differentiated Caco-2 cells, thus representing an effective ACE-2 encapsulation procedure for use with dry powders. Conclusions: This work showed that spray-freeze drying was the best method to dehydrate ACE-2 NPs, using less cryoprotectant to create a significant advantage in terms of greater loading capacity with lower additive requirements. Full article

The environmental impact and resource demands of traditional leather manufacturing have driven the search for sustainable alternatives. Fungal mycelium leather, recognised for its eco-friendly and renewable characteristics, has emerged as a promising option. This study established a cyclic freeze-thaw dehydration protocol for preparing mycelial leather using Ganoderma mycelium produced through liquid fermentation. By precisely controlling the fermentation parameters (pH 5.5, 150 rpm agitation, 28 °C), the liquid fermentation process ensures uniform mycelial growth, which is critical for subsequent structural enhancement during freeze-thaw cycles. After three freeze-thaw cycles were performed at −15 °C, uniformly distributed ice crystals facilitated effective water removal, achieving a minimum moisture content of 47.6%. The optimized freeze-thaw process produced membranes with a tensile strength of 6.22 MPa and elongation at break of 18.92%, demonstrating high mechanical performance. The freeze-thaw process was demonstrated to enhance structural integrity and mechanical properties while offering reduced energy consumption compared to conventional dehydration methods. This research provides a theoretical foundation and technical guidance for optimising fungal mycelium leather production and contributes to the development of sustainable bio-based materials for industrial applications. Full article

Enriched or fortified foods are typically linked to ultra-processed foods, limiting the choice of functional food in the market. Addressing the market potential, particularly the elder population with osteoporosis, the functional food industry should consider developing a healthy snack enriched with bioactive substances. This study aimed to produce freeze-dried Polish Gala apple with improved antioxidant properties and calcium content via impregnation or osmotic dehydration process. The solutions containing various concentrations of sea buckthorn (SB) juice and inulin were prepared at different temperatures and times, then analyzed by response surface regression modelling. Subsequently, the effect of the addition of 0–6% calcium lactate (CaL) on antioxidant properties and calcium content was also studied. Freeze-dried apple, after impregnation with 93.8% SB juice, 0:100 inulin–SB juice ratio, at 30 °C for 120 min, with the addition of 4% CaL (hereafter called “4% CaL” treatment), possessed a minimum yet acceptable loss of antioxidant properties and increased calcium content (2209.13 mg Ca/100 g). UPLC-PDA revealed the altered compositions of phenolics (flavonols were dominated by isorhamnetin-3-O-glucoside and isorhamnetin-3-O-rutinoside) and carotenoids in 4% CaL. The 4% CaL also exhibited lower polyphenol oxidase and peroxidase activities, moderate sensory acceptability with soft texture, and better nutritional values with lower calories when compared to the controls. This work is a scalable study, covering aspects of process design, physicochemical, nutritional, and enzymatic properties, as well as sensory profiling, which has potential for industrial implementation. Full article

Fish oil, a rich source of omega-3 polyunsaturated fatty acids (PUFA), is a vital nutritional component, but considering its susceptibility to oxidation, it could benefit from an effective encapsulation system. This study aims to optimize high-pressure homogenization (HPH) parameters (pressure, number of passes) and wall material composition to maximize the encapsulation efficiency (EE) of fish oil, using different concentrations of maltodextrin with Arabic gum or sodium alginate. Key metrics such as emulsion droplet size, encapsulation efficiency, color, and oxidation in the final freeze-dried product were evaluated. Optimal values were achieved at 60 MPa, resulting in the lowest mean droplet diameter (369.4 ± 3.8 nm) and narrow distribution (0.197 ± 0.011) of the fish oil micelles prepared with a mixture of Tween80 and sodium caseinate as an emulsifier, without significant oxidation after four cycles of homogenization, while 80 MPa led to the highest EE (up to 95.6%), but increased oxidation. The combination of 10% w/w Arabic gum or 1% w/w sodium alginate with 20% w/w maltodextrin achieved the highest EE (79.1–82.9%) and whiteness index (82.5–83.0), indicating neutral-colored well-encapsulated fish oil without oxidation, which is desirable for product stability. Selecting optimal HPH conditions and wall material is crucial for the encapsulation efficiency and oxidation stability of omega-3 PUFA delivered in dehydrated forms. Full article

In cryopreservation technology, the choice of cryoprotectant plays a crucial role in cell survival and function. Different types of cryoprotectants, each with unique protective mechanisms, mitigate cellular damage from ice crystal formation during freezing. This study investigated the effects of different types and concentrations of cryoprotectants on the cryopreservation efficacy of noble scallop Mimachlamys nobilis sperm. Six cryoprotectants were tested, including four permeable cryoprotectants (dimethyl sulfoxide (DMSO), ethylene glycerol (EG), propylene glycerol (PG), methanol (MET)) and two non-permeable cryoprotectants (trehalose (TRE), fetal bovine serum (FBS)). The results showed that permeable cryoprotectants, which penetrate the cell membrane, regulate the osmotic pressure inside and outside cells to reduce dehydration damage. Among them, 10% DMSO provided the best protection, significantly preserving sperm motility, velocity, and morphology. Non-permeable cryoprotectants, although unable to penetrate cells, stabilized the extracellular environment at higher concentrations (such as FBS). Additionally, MET and FBS exhibited enhanced protective effects with increasing concentration, indicating their potential in reducing sperm structural damage at higher concentrations. Morphological observations indicated that freezing caused varying degrees of structural damage to sperm, with flagellar integrity being crucial for motility. Overall, selecting an appropriate cryoprotectant and concentration is essential for the efficient cryopreservation of M. nobilis sperm, providing a valuable reference for conserving germplasm resources of marine species. Full article

Waste slurry, a major by-product of urban construction, is produced in rapidly increasing volumes each year. Dehydrated waste slurry has potential as a roadbed material; however, its performance in freeze–thaw environments, which can induce frost heave and thaw settlement, and the mechanism of the influence of freeze–thaw cycles on its macro and micro properties are still unclear and need thorough investigation. This study explores the macroscopic and microscopic properties of waste slurry subjected to freeze–thaw cycles. We conducted unconfined compressive strength (UCS) and triaxial unconsolidated undrained (UU) shear tests, focusing on fissure compaction, elastic deformation, plastic yielding, and strain hardening stages. The results reveal a decrease in strength and elastic modulus with increasing freeze–thaw cycles, as well as in the damage degree generated by freeze–thaw cycles. To uncover the underlying microscopic mechanisms, we performed Scanning Electron Microscopy (SEM), X-ray diffraction (XRD), and mercury intrusion porosimetry (MIP) analyses. These tests highlighted the evolution of pores and microcracks during freeze–thaw cycles. These results have important reference values for the reutilization of waste slurry discharged from large-diameter bored piles for roadbed backfill materials that need to be repaired quickly in seasonally frozen areas. Full article

Stems are a major by-product of mushroom production. This study optimizes the transformation of Agaricus bisporus stems (ABS) and Pleurotus ostreatus stems (POS) into flour. ABS are attached to the peat, so, the process was divided into two steps. First, four cleaning methods were tested for ABS: pre-drying, brushing, abrasive peeling, and immersion in chlorinated water and brushing. Abrasive peeling was the most effective, showing the lowest color difference (9.18), total aerobic count (3.48 log cfu/g), and the highest profitability (1 kg/h). In the second step, ABS and POS were dried using a freeze-dryer, a dehydrator, and an oven. Dehydration resulted in stems with a lower browning index (24.57 in ABS and 29.95 in POS) than the oven, and a smaller energy consumption than the freeze-dryer. Finally, three dehydration temperatures (40, 50, and 60 °C) were compared. Dehydration at 50 °C resulted in faster moisture loss (24 h) and similar phenolic compound concentrations (3.35 and 7.69 mg GAE/100g fresh ABS and POS, respectively) than at 40 °C (32 h in ABS and 28 h in POS). In conclusion, the transformation of ABS and POS into flours requires processes that influence their chemical composition, physicochemical characteristics, and the profitability of their production. In this project, the optimal process involved cleaning ABS through abrasive peeling and dehydrating both ABS and POS at 50 °C for 24 h. Full article

Sweet potato (Ipomoea batatas (L.) Lam.) is a nutrient-dense crop rich in fibre, minerals, and antioxidant compounds, including carotenoids and phenolic compounds, such as anthocyanins. Dehydrating sweet potato (SP) for flour production enhances its value and produces shelf-stable, health-promoting food products. This study investigated the effects of hot-air drying (HAD: 75 °C/20 h) and freeze-drying (FD: −41–30 °C/70 h) on the bioactive composition of flours from three SP varieties: Bonita (white-fleshed), Bellevue (orange-fleshed), and NP1648 (purple-fleshed). Key assessments included the total phenolic content (TPC), the total carotenoid content (TCC), and the total anthocyanin content (TAC) and the antioxidant activity (DPPH and FRAP). The results revealed distinct raw materials’ bioactive profiles: Bellevue was rich in TCC (49.3 mg of β-carotene/100 g db), NP1648 showed elevated TAC (27.3 mg of cyanidin-3-glucoside/100 g db), and Bonita exhibited minimal content of bioactive compounds. Both drying methods yielded significant losses of bioactive compounds, with the TPC decreasing by over 60%, while TAC and TCC losses did not exceed 32%, revealing higher stability. Multivariate analysis indicated that the variety significantly influenced the bioactive profiles more than the drying method. The interaction between carotenoids and anthocyanins and the SP fibrous composition likely contributed to their stability during drying, indicating that FD showed no advantages over HAD. The appealing colours and high antioxidant content of Bellevue and NP1648 flours suggest their potential as ingredients for enhancing foods’ bioactivity and sensory acceptance. Full article

Osmotic dehydration as a process of removing water from food by immersing the raw material in a hypertonic solution is used primarily to extend the shelf life of products and as a pretreatment before further processing steps, such as drying and freezing. However, due to the bi-directional mass transfer that occurs during osmotic dehydration, the process can also be used to shape sensory properties and enrich the plant matrix with nutrients. The purpose of this study was to evaluate the effect of osmotic dehydration on the absorption of potassium by beet pulp immersed in various hypertonic solutions (sucrose, inulin, erythritol, xylitol solutions) with the addition of three chemical forms of potassium (gluconate, citrate, chloride) using variable process conditions. The study proved that osmotic dehydration is an effective way to enrich food. The highest potassium content (5779.03 mg/100 g) was found in a sample osmotically dehydrated in a 50% erythritol solution with 5.0% potassium chloride addition with a process that lasted 180 min and took place at 30 °C. The results obtained indicate the high potential of osmotic dehydration in improving the health values of food products. In addition, the antioxidant activity and proximate composition of osmotically dehydrated samples were also characterized in this study. Full article