Search Results (24)

The cryopreservation of ovarian tissues from fish has recently been carried out for several endangered and commercially valuable species. However, previous studies in this context have focused on the cryopreservation of immature ovaries—mainly through slow freezing and vitrification—which requires specialized freezing equipment or higher cryoprotectant concentrations to keep cell viability. Therefore, the aim of this study was to explore a convenient, rapid, efficient and less toxic method for the cryopreservation of ovaries at the stage of vitellogenesis from yellow drum (Nibea albiflora), an economically important marine fish. The ovaries at the stage of vitellogenesis were isolated and cut into blocks of approximately 1 cm³, then cryopreserved with 15% propylene glycol (PG), fetal bovine serum (FBS) and 0.2 M trehalose as cryoprotectants. Finally, the samples were treated using three different freezing procedures, including a −80 °C refrigerator, liquid nitrogen, and their combination. After 7 days, the tissues were thawed and digested, and the cell survival rates and gene expression levels were detected using cell viability assay kits and qRT-PCR, respectively. The results of the viability assay showed that the procedure of ovarian tissue storage at −80 °C in a refrigerator for 1 h, followed by transfer to liquid nitrogen, resulted in the highest cell survival rate (>90%). Furthermore, the germ cells at various phases were of normal size; presented a full, smooth surface and regular shape; and did not show any signs of cell rupture, atrophy, depression, granulation or cavitation. Furthermore, the qRT-PCR results revealed that genes related to reproductive development, such as vasa, foxl2, zp3 and gsdf, were all down-regulated under the optimal protocol, while the expression of the nanos2 gene (which is specifically distributed in oogonia) maintained a higher level, similar to that in the control group. This indicated that the viability of germ stem cells (oogonia) was not weakened after freezing and that oogonia could be isolated from the cryopreserved ovaries for germ cell transplantation. The present study successfully establishes an optimal cryopreservation protocol for ovarian tissues from Nibea albiflora, providing reference for the preservation of ovaries at the stage of vitellogenesis from other species. Full article

Cryopreservation of native Thai bull semen often results in significant post-thaw quality reduction, underscoring the need for effective cryoprotective strategies. This study investigated the effect of Moringa oleifera leaf extract (MOLE) as an antioxidant supplementation by incorporating four MOLE concentrations (0–1.5% [w/v]) into a standard semen extender, followed by cryopreservation using liquid nitrogen vapor freezing. Data were analyzed using a randomized complete block design with Tukey’s post hoc test (p < 0.05). Post-thaw analysis of semen revealed that 1 mg/mL MOLE significantly enhanced total sperm motility, progressive sperm motility, sperm viability, and sperm plasma membrane integrity compared to the control and other MOLE concentrations (p < 0.05). This concentration also improved the amplitude of lateral head displacement and curvilinear velocity and reduced malondialdehyde levels in semen samples (p < 0.05), indicating reduced lipid peroxidation. Higher MOLE concentrations negatively impacted semen quality. In conclusion, supplementation with 1 mg/mL MOLE markedly improved post-thaw semen quality and reduced lipid peroxidation, suggesting its potential as an antioxidant for enhancing reproductive outcomes in native Thai bulls. Full article

This research aimed to evaluate block freeze concentration (BFC) under different centrifugation conditions using response surface methodology to separate an extract from the ice fraction at three centrifugal-BFC (CBFC) cycles, obtaining in the final cycle a phenolic-rich extract. A Box–Behnken design was applied to optimize centrifugation variables, with efficiency of separation (η) selected as the response variable. The extracts were characterized in terms of physicochemical analysis, total and individual bioactive components, and antioxidant capacity. Optimal conditions (3600 rpm, 16 °C, and 14 min) resulted in η of 82%. Thus, from infusion to final cycle, the solids, total polyphenol and flavonoid contents, and antioxidant capacity exhibited from 1.81 to 6.5% (w/w) and 2.5 to 8.7 (°Brix), 0.72 to 12.2 mg gallic acid equivalents/mL, 0.83 to 13.7 mg catequin equivalents /mL, 2.8 to 31.2 μmol trolox equivalents/mL and 4.8 to 122.2 μmol trolox equivalents/mL, identifying by high-performance liquid chromatography that kaempferol, p-hydroxybenzoic, and transferulic acid presented the highest concentrations. The CBFC process has the potential as a non-thermal concentration process to preserve many bioactive compounds, facilitating the production of concentrated fractions with high biological value, where the extracts obtained by BFC are a novel solution for medicinal, pharmaceutical, and food applications. Full article

Alginate hydrogels have gathered significant attention in biomedical engineering due to their remarkable biocompatibility, biodegradability, and ability to encapsulate cells and bioactive molecules, but much less has been reported on the kinetics of gelation. Scarce experimental data are available on cross-linked alginates (AL) with bioactive components. The present study addressed a novel method for defining the crosslinking mechanism using rheological measurements for aqueous mixtures of AL and calcium chloride (CaCl₂) with the presence of hydroxyapatite (HAp) as filler particles. The time-dependent crosslinking behaviour of these mixtures was exploited using a plate–plate rheometer, when crosslinking occurs due to calcium ions (Ca²⁺) binding to the guluronic acid blocks within the AL polymer, forming a stable “egg-box” structure. To reveal the influence of HAp particles as filler on crosslinked sample morphology, after rheological measurement and crosslinking, crosslinked samples were freeze-dried and their morphology was assessed using an optical microscope and SEM. It was found that the addition of HAp particles, which are known to enhance the mechanical properties and biocompatibility of crosslinked AL gels, significantly decreased (usually rapidly) the interaction between the Ca²⁺ and AL chains. In this research, the physical “shielding” effect of HAp particles on the crosslinking of AL with Ca²⁺ ions has been observed for the first time, and its crosslinking behaviour was defined using rheological methods. After crosslinking and rheometer measurements, the samples were further evaluated for morphological properties and the observations were correlated with their dewatering properties. While the presence of HAp particles led to a slower crosslinking process and a more uniform development of the rheological parameters, it also led to a more uniform porosity and improved dewatering properties. The observed effects allow for a better understanding of the crosslinking process kinetics, which directly affects the physical and chemical properties of the AL gels. The shielding behaviour (retardation) of filler particles occurs when they physically or chemically block certain components in a mixture, delaying their interaction with other reactants. In hydrogel formulations, filler particles like hydroxyapatite (HAp) can act as barriers, adsorbing onto reactive components or creating physical separation, which slows the reaction rate and allows for controlled gelation or delayed crosslinking. This delayed reactivity is beneficial for precise control over the reaction timing, enabling the better manipulation of material properties such as crosslinking distribution, pore structure, and mechanical stability. In this research, the physical shielding effect of HAp particles was observed through changes in rheological properties during crosslinking and was dependent on the HAp concentration. The addition of HAp also enabled more uniform porosity and improved dewatering properties. The observed effects allow for a better understanding of the crosslinking process kinetics, which directly affects the physical and chemical properties of the AL gels. Full article

Precambrian tropical glaciation is an enigma of Earth’s climate. Overlooking fundamental difference of land/sea icelines, it was equated with a global frozen ocean, which is at odds with the sedimentary evidence of an active hydrological cycle, and its genesis via the runaway ice–albedo feedback conflicts with the mostly ice-free Proterozoic when its trigger threshold was well exceeded by the dimmer sun. In view of these shortfalls, I put forth two key hypotheses of the tropical glaciation: first, if seeded by mountain glaciers, the land ice would advance on sea level to be halted by above-freezing summer temperature, which thus abuts an open cozonal ocean; second, a tropical supercontinent would block the brighter tropical sun to cause the required cooling. To test these hypotheses, I formulate a minimal tropical/polar box model to examine the temperature response to a varying tropical land area and show that tropical glaciation is indeed plausible when the landmass is concentrated in the tropics despite uncertain model parameters. In addition, given the chronology of paleogeography, the model may explain the observed deep time climate to provide a unified account of the faint young Sun paradox, Precambrian tropical glaciations, and Phanerozoic glacio-epochs, reinforcing, therefore, the uniformitarian principle. Full article

Although eicosapentaenoic acid (EPA) as a functional fatty acid has shown significant benefits for human health, its susceptibility to oxidation significantly limits its application. In this study, we developed a nanoemulsion of the lactoferrin (LTF)–EPA complex and conducted a thorough investigation of its macro- and molecular properties. By characterizing the emulsion with different LTF concentrations, we found that 1.0% LTF formed the most stable complex with EPA, which benefited the formation and stability of the emulsion against storage and freezing/thawing treatment. As the foundation block of the emulsion structure, the binding mechanism and the entire dynamic reaction process of the complex have been fully revealed through various molecular simulations and theoretical calculations. This study establishes a comprehensive picture of the LTF–EPA complex across multiple length scales, providing new insights for further applications and productions of its emulsion. Full article

The development of functional dairy products has increasingly become a focus of the dairy industry, with goat milk gaining prominence due to its nutritional properties and digestibility. This study aimed to evaluate the effects of freeze concentration processes on skimmed goat milk, observing its potential prebiotic effects and impacts on the physical, chemical, microbiological, rheological, and sensory profiles of fermented milk, using the Preferred Attributes Elicitation (PAE) methodology. Skimmed goat milk was initially concentrated using the gravitational block freeze concentration technique. A fermented milk containing probiotics (FM1) was produced from this concentrate. In addition, two other samples were developed: one with skimmed goat’s milk, 6% inulin, and probiotics (FM2) and another using whole goat’s milk with probiotics as a control (FM3). The results indicated that the freezing concentration process resulted in a concentrate with 14.70 ± 0.06 g 100 g⁻¹ of total solids. Among the three types of fermented milk, FM1 presented the highest values of total solids and titratable acidity. Regarding color, both FM1 and FM2 tended towards yellowish and greenish tones, while FM3 presented a greater luminosity. During storage, all fermented milks maintained their probiotic properties. The freeze concentration process increased the viscosity of FM1, a characteristic also evidenced in the sensory evaluations using PAE. In contrast, FM2 presented a rheological behavior similar to that of the control (FM3). Regarding sensory acceptance, FM1 had lower acceptance regarding aroma, being described as having notes of “goat flavor” and “acid” and being “salty”. The PAE methodology proved effective in characterizing the sensory qualities of the products, providing valuable information for developing new dairy products. These results offer an important theoretical basis for the industrial production of functional dairy products based on goat’s milk, helping to evaluate quality characteristics and optimize manufacturing processes. Full article

The freeze concentration of liquid foods generates a by-product that has few academic studies and no industrial application: the ice fraction of each concentration stage. Sugar-free carbonated beverages were produced from the addition of 20% residual ice fraction (stage 1—I120 and stage 2—I220) of the gravitational block freeze concentration process, and the result was compared with a control beverage produced with 20% guabiroba juice (J20). The physicochemical properties, carotenoid content, total phenolic content (TPC), vitamin C, and antioxidant activity were analyzed for all samples. There was no significant difference between J20 and I220 for the total solid content and total soluble solids. For the total phenolic compounds (TPC), the I220 content was 151.3% higher than that of the original juice J20 and, for antioxidant activity, 295.8% higher for ABTS and 130.2% higher for DPPH. The I220 beverage presented 159% more vitamin C content than the beverage containing juice (J20). The same behavior was observed for each carotenoid content, with 168% more for the I220 sample. The total color difference revealed no difference visible to the naked eye for the three formulated beverages (∆E < 3.0; p < 0.05). The promising results of the bioactive compounds from guabiroba juice retained in the ice fraction can add value to this process waste in the formulation of new products due to the remaining functional appeal of the original fruit matrix. Full article

Cold-pressed guabiroba juice was subjected to block freeze concentration. The best process efficiency (PE) was obtained for the first stage of freeze concentration compared to the second stage (C2; 57.47%). Yogurt formulations were carried out with the concentrated juice from stage 1 (C1) (0, 10% (I10), and 15% (I15)). For all concentrated juices (C1 and C2), ice fractions from the first and second stages (I1 and I2), and yogurts (control, I10, and I15), physicochemical analyses were performed and antioxidant activity, carotenoid content, total phenolic content (TPC), and mineral profile were determined. Total soluble solids contents for the concentrated juices increased by 1.56 to 2 times compared to the cold-pressed guabiroba juice. Furthermore, an increase in TPC and carotenoids was observed. For the I15 sample, TPC increased by 4,556%, with the control and increased carotenoids, vitamin C, and mineral profiles (Ca, K, Mg, and Na) contributing to increased antioxidant activity. The addition of concentrated guabiroba juice to yogurt formulations enhances the functional property of this dairy product by maintaining most of the bioactive compounds during cold-pressing associated with the freeze concentration. Full article

Modernization has led to a large convenience food market, and the demand for freeze-dried (FD) soup products is increasing in the Republic of Korea. FD soup products are easy to eat without cooking and can be stored for long periods. However, it is often difficult to ensure sensory satisfaction after rehydration of FD soup products; in particular, the ingredients are not evenly dispersed. Therefore, a stable dispersion or reconstitution of the FD soup products is required after rehydration. Here, the effects of high-speed shearing homogenization on the physical properties of a carbohydrate-binder mixture comprising maltodextrin, potato starch, and rice flour were investigated during hydrothermal gelatinization. To find a suitable treatment condition, different homogenization eras, speeds, and concentrations of the binder mixture were considered; in particular, the homogenization eras were set by considering the hydrothermal property of the binder mixture profiled using differential scanning calorimetry. The viscosity of the binder mixture and the compression strength and microstructure of the FD binder block, including the dispersion stability after rehydration, were evaluated. The quality of the FD binder block was improved by homogenization above 5000 rpm when the core temperature of the binder mixture reached approximately T_o at 14.5–21.8% concentrations. The improved FD binder block exhibited a fine surface and tiny porous microstructure compared with the control (with continuous agitation at 250 rpm). The control block was divided into two phases, whereas the improved block maintained the initial dispersion stability at 50 °C for 1 h. These results are expected to be referenced for the purpose of improving the quality of the FD soup products. Full article

In recent years, China has increased the material utilization of crop straw, and the strength of straw–mortar composite wall materials is low, which limits their large-scale utilization. Pretreatment can improve the physico-mechanical and frost resistance properties of straw–mortar composite wall materials. In this study, the Box–Behnken design in the Design-Expert software was used to design and carry out a three-factor and three-level interactive experiment and freeze–thaw cycle experiment with the straw content, pretreatment time, and reagent concentration as influencing factors, and the compressive strength, water absorption rate, and dry density as response values. The results showed that the impact of each factor on the response value, from high to low, was the straw content, pre-preparation time, and reagent concentration. When the straw content was 10%, the preparation time was 5 min, and the reagent concentration was 5%, the physical and mechanical properties of the straw–mortar composite wall material were the best. At the same time, the compressive strength was 6.52 MPa, the water absorption rate was 17.7%, and the dry density was 1396.33 kg·m⁻³, which was 67% higher, 31% lower, and 37% higher than that of the untreated straw–mortar composite wall materials. After the freeze–thaw cycle, the mass loss rate of the composite materials was less than 5%, which met the requirements of the frost resistance specifications; the strength loss rate of the composite materials varied between 19.7% and 27.8%, although some test blocks did not meet the requirements of less than 25% in the specification. The compressive strength was greatly improved compared with the untreated composite materials in the related research, and the water absorption rate was about 25% lower than that of the untreated straw–mortar composite wall materials. Pretreatment significantly improved the physico-mechanical and frost resistance properties of the straw–mortar composite wall materials. Full article

Sweet corn is frequently consumed in the US and contains carbohydrates as major macronutrients. This study examined the effects of blanching, freezing, and canning on carbohydrates in sweet corn. Fresh bi-color sweet corn was picked in the field and processed immediately into frozen and canned samples. Simple sugars, starch, and dietary fiber (DF) (including total DF (TDF), insoluble DF (IDF) and two fractions of soluble DF (SDF)) were measured according to the AOAC methods. Additional glycomic analysis including oligosaccharides, monosaccharide composition of total polysaccharides (MCTP) and glycosidic linkage of total polysaccharides (GLTP) were analyzed using UHPLC-MS. Sucrose is the major simple sugar, and IDF is the main contributor to TDF. Sucrose and total simple sugar concentrations were not altered after blanching or freezing but were significantly reduced in canned samples. Kestose was the only oligosaccharide identified in sweet corn and decreased in all heat-treated or frozen samples. Starch content decreased in frozen samples but increased in canned samples. While two SDF fractions did not differ across all samples, blanching, freezing and canning resulted in increases in TDF and IDF. Six monosaccharides were identified as major building blocks of the total polysaccharides from MCTP analysis. Glucose and total monosaccharide concentrations increased in two canned samples. GLTP was also profoundly altered by different food processing methods. This study provided insights into the changes in the content and quality of carbohydrates in sweet corn after food processing. The data are important for accurate assessment of the carbohydrate intake from different sweet corn products. Full article

A model (sucrose and gallic acid) solution was concentrated by block freeze concentration (BFC) at three centrifugation cycles, and the solutions were encapsulated in calcium alginate and corn starch calcium alginate hydrogel beads. Static and dynamic tests determined the rheological behavior, differential scanning calorimetry (DSC) and Fourier transform infrared spectroscopy (FTIR) established thermal and structural properties, and the release kinetics was evaluated under in vitro simulated digestion experiment. The highest efficiency encapsulation value was close to 96%. As the concentrated solution increased in terms of solutes and gallic acid, the solutions were fitted to the Herschel–Bulkley model. Moreover, from the second cycle, the solutions exhibited the highest values of storage modulus (G′) and loss modulus (G″), contributing to form a more stable encapsulation. The FTIR and DSC results demonstrated strong interactions between corn starch and alginate, establishing a good compatibility and stability in the bead formation. The kinetic release model under in vitro conditions was fitted to the Korsmeyer–Peppas model, demonstrating the significant stability of the model solutions inside the beads. Therefore, the present study proposes a clear and precise definition for the elaboration of liquid foods obtained by BFC and its incorporation inside an edible material that facilitates the controlled release in specific sites. Full article

Because of the increasing scarcity of water resources, the desalination of seawater by photothermal evaporation with harvested solar energy has gradually become a popular research topic. The interconnected macroporous cryogel prepared from polymerization and crosslinking below the freezing temperature of the reactant solution has an excellent performance in photothermal water evaporation after loading photothermal materials. In this study, polyacrylamide (PAM) cryogels were prepared by cryo-polymerization and sulfonated in an alkaline solution containing formaldehyde and Na₂SO₃. Importantly, the evaporation enthalpy of water in sulfonated PAM cryogel was reduced to 1187 J·g⁻¹ due to the introduction of sulfonate groups into PAM, which was beneficial to increase the photothermal evaporation rate and efficiency. The sulfonated PAM cryogels loaded with polypyrrole and the umbrella-shaped melamine foam substrate were combined to form a photothermal evaporation device, and the evaporation rate was as high as 2.50 kg·m⁻²·h⁻¹ under one-sun radiation. Meanwhile, the evaporation rate reached 2.09 kg·m⁻²·h⁻¹ in the 14 wt% high-concentration saline solution, and no salt crystals appeared on the surface of the cryogel after 5 h of photothermal evaporation. Therefore, it was evidenced that the presence of sulfonate groups not only reduced the evaporation enthalpy of water but also prevented salting-out from blocking the water delivery channel during photothermal evaporation, with a sufficiently high evaporation rate, providing a reliable idea of matrix modification for the design of high-efficiency photothermal evaporation materials. Full article

Garlic (Allium sativum) contains secondary compounds that are known to modify rumen fermentation parameters and decrease methane (CH₄) emissions. The objective was to evaluate the effects of increasing the inclusion levels and processing methods of garlic on in vitro fermentation and CH₄ production. Treatments were arranged in a randomized complete block design with a 2 × 3 × 2 + 1 factorial arrangement, where the main factors were the initial condition of garlic (intact or smashed), drying process (freeze-dried, oven-dried, or autoclaved), and garlic proportion in the diet (2.5 and 5%) and one control (without garlic supplementation). Incubations were conducted using corn silage and cotton-gin trash (80:20, respectively) as basal substrates on three different days. Final pH, the concentration of volatile fatty acids (VFA) and ammonia nitrogen (NH₃-N), in vitro organic matter digestibility (IVOMD), total gas production, and CH₄ concentration were determined after 24 h. Initial garlic condition or drying processing neither modify (p > 0.05) the in vitro fermentation nor the CH₄ production. However, increasing garlic inclusion linearly increased (p < 0.05) IVOMD, the concentration of the total VFA, and the proportion of propionate. Also, the concentration of NH₃-N and the proportion of acetate increased quadratically (p < 0.05) with greater garlic inclusions. Finally, garlic inclusion did not affect (p > 0.05) gas and CH₄ production. In conclusion, increasing garlic levels, but not the processing methods, improved in vitro fermentation but did not modify CH₄ emissions under in vitro conditions. Full article