Cryoprotective Effect Research Articles

No synergistic effect of extracellular cryoprotectants with dimethyl sulfoxide in the conservation of northern tiger cat fibroblasts

The success of somatic cell cryobanks is dependent on establishing reproducible cryopreservation methodologies. We supposed that associated extracellular cryoprotectants (sucrose and L-proline) with 2.5 or 10 % dimethyl sulfoxide (Me2SO) could guarantee better northern tiger cat cells quality rates after thawing when compared to Me2SO alone. Therefore, we evaluated the effects of sucrose or L-proline with 2.5 or 10 % Me2SO on the cryopreservation of northern tiger cat fibroblasts. Somatic cells were also cryopreserved with 2.5 % or 10 % Me2SO alone. All cells were analyzed for morphology, membrane integrity, proliferative activity, metabolism, apoptosis classification, reactive oxygen species (ROS) levels, and mitochondrial membrane potential (ΔΨm). Regardless of the cryoprotective solution, cryopreservation did not affect morphology, membrane integrity after culture, proliferative activity, and metabolism (P > 0.05). However, immediately after thawing, 2.5 % Me2SO with L-proline and 10 % Me2SO promoted higher rates of membrane integrity when compared to the other cryopreserved groups (P < 0.05). Interestingly, cells cryopreserved with 10 % Me2SO maintained ROS levels similar to non-cryopreserved cells (P > 0.05). However, the percentage of viable cells evaluated by apoptosis classification was reduced when using 10 % Me2SO with L-proline compared to non-cryopreserved groups (P < 0.05). Additionally, ΔΨm was altered in all cryopreserved groups (P < 0.05). In summary, sucrose and L-proline were less effective in cryopreservation of northern tiger cat fibroblasts in the presence of 2.5 % or 10 % Me2SO. Also, 10 % Me2SO appears to be the most suitable cryoprotectant for the formation of cryobanks of this species.

PKA and NBC expression patterns in cryopreserved bovine spermatozoa after kaempferol treatment

Kaempferol (KAE) is a member of the flavonoid family, which exhibits antioxidant properties. The richest sources of KAE are green leafy vegetables and herbs like kale, spinach or dill. The goal of our study was to evaluate a possible cryoprotective effects of KAE through to gene expression of protein kinase A (PKA) and sodium bicarbonate cotransporter (NBC). For the experiments we used semen samples obtained from 12 adult Holstein bulls. Before cryopreservation, all samples were divided equally and supplemented by different concentrations of KAE (0, 12.5, 25 and 50 µmol/L), except for native control. After that, RNA was isolated, and the purity and quality of RNA was verified nanophotometrically at A260/A280 nm. Next step was a transcription of RNA into cDNA, which was used for two-step qPCR while expression of PKA and NBC was quantified under specific cycling conditions. Data was evaluated by the delta delta Ct method and One-way ANOVA using Tukey’s range test. According to expression patterns, it was observed that 25 µmol/L of KAE significantly preserved (P&lt;0.0001) the PKA compared to cryopreserved control without KAE treatment. In the case of NBC, there was slightly increase of expression in the group treated with 50 µmol/L of KAE but without significant changes. In conclusion, KAE treatment exhibit promising cryoprotective properties of PKA and NBC genes especially in higher concentration 25 and 50 µmol/L, which may successfully preserved proper expression after thawing of cryopreserved bovine spermatozoa.

Cryo-protective effect of ice-binding proteins produced by Pseudomonas fluorescens AQP671 on wholegrain wheat bread dough during freezing and frozen storage

Cryo-protective effect of ice-binding proteins produced by Pseudomonas fluorescens AQP671 on wholegrain wheat bread dough during freezing and frozen storage

Studies on the Quality and Antioxidant Status of Cryopreserved Pantja Buck Semen Supplemented with Aqueous Extract of Rosemary and Sericin in Tris Extender.

Introduction: Rosemary shrub/plant and Sericin have been documented to show antioxdative properties, however their role in improving post thaw semen quality has not been well established. Objectives: The present study was conducted to investigate the effect of Rosemary leaves extract and Sericin protein on post-thaw quality of Pantja buck semen. Methods: In the first experiment, 32 ejaculates were collected from 4 sexually mature Pantja bucks and pooled to form 8 pooled samples. The pooled samples were evaluated for seminal attributes (sperm motility, viability, morphology, plasma membrane integrity, and acrosomal integrity), status of antioxidative enzymes (superoxide dismutase, catalase, glutathione peroxidase, and glutathione reductase) and lipid-peroxidation (malondialdehyde) of sperm plasma membrane before dilution. In the second experiment, pooled samples were divided into three equal aliquots as group-C (Control), group-R (Rosemary), and group-S (Sericin). Aliquots of group-C were diluted in glycerolated Egg Yolk Tris (EYT) extender, whereas aliquots of group-R and group-S were additionally supplemented with 4.0% v/v Rosemary leaves extract and 0.25% w/v Sericin, respectively, and again examined for the above parameters at the post-dilution, post-equilibration, and post-thawing stages of semen freezing. Results: Significant differences (p < 0.05) were observed in the values of seminal attributes, level of enzymatic antioxidants, and lipid per-oxidation between group C and R and between group C and S at the post-thaw stage of semen freezing. However Sericin was nonsignificantly better than Rosemary in improving post-thaw semen quality. Conclusion: The results of the present study on limited semen samples in Pantja buck demonstrated that compared to the control group, both Rosemary aqueous extract (4%) and Sericin protein (0.25%) as an additive in TRIS extender, showed better cryoprotective effects resulting in improved post-thaw seminal characteristics.

Effect of pectin with different esterification degree on the freeze-thaw stability of gluten protein: Structures, functional properties, and Cryoprotective mechanism

The effect of degree of esterification (DE) on the cryoprotective function of pectin against the frozen deterioration of gluten protein is still unclear. Here, NMR, HPSEC-MALLS, HPGPC and optical microscrope were applied to determine the structure and ice recrystallization inhibition (IRI) activity of pectin with varying DE. The effect on structure, physicochemical properties and molecular interaction of gluten supplemented with pectin were investigated. Results suggested that low-ester pectin (LEP) exhibited higher IRI activity than that of high-ester pectin (HEP), and reduced the damage of gluten during freezing storage. Moreover, SEM and low field-NMR revealed that LEP effectively helped to maintain the network structure and inhibited the water migration of gluten. Besides, molecular docking results suggested higher affinity between LEP and gluten protein than that of HEP. These results illustrated better cryoprotective effects of LEP than that of HEP through pathways including IRI activity, water migration, and possible molecular interaction.

Cryoprotective Effect of Zinc and Gold Nanoparticles During Cooling and Freeze-thawing on Marwari Stallion Sperm Parameters and Reactive Oxygen Species Production

BACKGROUND: Sperm cryopreservation is one of the most important procedures in the development of biotechnologies for assisted reproduction. Cryopreservation of stallion spermatozoa tends to cause plasma membrane damage due to the low ratio of cholesterol to phospholipids. Different substances and compounds can be added to semen extenders to improve sperm quality. OBJECTIVE: To investigate the effect of supplementing semen extender with zinc nanoparticles (ZnONPs) and gold nanoparticles (AuNPs) on cooled and frozen-thawed spermatozoa of Marwari stallion. MATERIALS AND METHODS: A total of 20 ejaculates from four Marwari stallions (five ejaculates from each) were collected. The gel free semen was extended with primary extender in equal volume and then divided in three equal groups, namely control (C), zinc (ZnO) and gold (Au), and centrifuged to obtain a final concentration of 100-150 x10 6 mL -1 and then cryopreserved. Cooled and post-thaw semen evaluations were conducted for various seminal characteristics, viz. progressive sperm motility, sperm plasma membrane integrity, sperm viability, acrosome integrity and mitochondrial membrane potential. RESULTS: Cooled semen (4ºC for 2 h) evaluation revealed nonsignificant differences among the groups (C, ZnO and Au) for all the semen quality parameters. However, at the post-thaw stage, progressive sperm motility, sperm plasma membrane integrity, acrosome integrity and oxidative parameters were significantly (P≤ 0.01) higher in the ZnO group than Au and C. CONCLUSION: The addition of ZnO nanoparticles improves the post thaw quality of stallion spermatozoa by reducing the oxidative stress, but Au nanoparticles had no effect on cooled as well as post-thaw semen quality.

Investigation of the efficacy of different cryoprotectants in the freezing of testicular tissue and epididymal sperm: Spermatological parameters, tissue viability and PARP-1 gene expression

The presented study covers testicular tissue and epididymal spermatozoa cryopreservation processes in bulls and aims to investigate the effects of these applications on spermatological parameters, cell viability in testicular tissue, and the expression of the PARP-1 gene, a DNA repair enzyme. Testes of 20 bulls over 2 years old, slaughtered in a slaughterhouse, were used in the study. After spermatological evaluations, the semen obtained from the cauda epididymis was frozen in liquid nitrogen vapor according to the straw method and stored in liquid nitrogen (−196 °C). Testicular tissue pieces obtained from the testicles were frozen by the slow freezing method in cryotubes in diluents containing Dimethylsulfoxide (DMSO) and Ethylene Glycol (EG) cryoprotectants and stored in liquid nitrogen (−196 °C). The total motility (TM) (85.89 ± 12.83 %), progressive motility (PM) (54.02 ± 15.77 %), and kinematic parameter values of fresh sperm were significantly higher compared to the TM (57.62 ± 13.13 %), PM (29.60 ± 10.76 %), and kinematic parameter values after thawing (P < 0.05). Significant decreases in plasma membrane integrity (PMI) and viability and an increase in chromatin condensation and morphological disorders in the head, middle part, and tail regions were observed in post-thaw semen samples (P < 0.05). When the effects of DMSO and EG on cell viability after thaw in frozen testicular tissue were evaluated, it was observed that the cell viability values of testicular tissues frozen with EG (45.70 ± 10.00) were statistically significantly lower than those frozen with DMSO (51.20 ± 7.70) (P < 0.05). When the effects of both cryoprotectants on gene expression in tissue and semen samples were examined, it was determined that gene expression increased on average 0.19 ± 0.27 times in the tissue samples in the DMSO group compared to fresh tissue samples and 0.17 ± 0.19 times in the tissue samples in the EG group. It was determined that gene expression levels increased by an average of 1.20 ± 1.08 times in post-thaw epididymal spermatozoa samples compared to fresh semen samples. The results show that cryopreservation can activate cellular repair mechanisms by stimulating PARP-1 gene expression and affect gene expression by activating specific pathways in tissues and cells.

Prunella vulgaris and Tussilago farfara demonstrate anti-inflammatory activity in rabbits and protect human adipose stem cells against thermal stress in vitro

Ethnopharmacological relevancePrunella vulgaris L.(PV) and Tussilago farfara (TF) are perennial herbs rich in flavonoids and phenolic compounds with immense medicinal value. PV extract (PV-E) possesses potent antipyretic, anti-inflammtory, antioxidant, antiseptic, anti-cancer and immune stimulatory properties and have been traditionally known for the treatment of wounds, ulcers and sores. TF extract (TF-E) has been known for antibacterial, antioxidant, anti-inflammatory, anti-viral, anti-diabetic, anti-cancer, anti-obesity and wound healing effects. Additionally, TF-E infusions have been used for asthma, cough, and bronchopneumonia treatments. Aim of the studyThe therapeutic efficacy of transplanted human adipose stem cells (hASCs) is abrogated under the deteriorating effects of heat stress offered by burn wounds. Earlier researches has documented antioxidant priming as an effective strategy to enhance stem cell performance. As both PV-E and TF-E are known for their potent antioxidant effects. The present study aims to examine the cryoprotective effects of PV-E and TF-E priming on hASCs against in-vitro heat-induced thermal stress. Moreover, we determined the anti-inflammatory potential of both PV-E and TF-E on rabbits. MethodsAntioxidant capacity of both PV-E and TF-E is examined via DPPH assay and anti-inflammatory activity is assessed in rabbits using carrageen-induced paw edema model of inflammation. Next, we investigate the efficacy of different doses (1.25–100 μg/ml) of PV-E and TF-E on hASCs; MTT, LDH, calcein AM staining, and wound scratch assay were used to assess cell viability, cytotoxicity, proliferation ability and cell migration potential in the cells. Then, hASCs were pretreated for 24 h with optimum doses of PV-E and TF-E determined from MTT assay results and were subsequently exposed to in-vitro thermal injury (51 °C,10 min). The cytoprotective effects of both PV-E and TF-E priming under thermal stress were investigated via MTT, LDH, annexin-V staining and gene expression analysis. ResultsBoth PV-E and TF-E extracts demonstrated potent antioxidant and effective anti-inflammatory activities, with a clear reduction in inflammation. Study on hASCs exhibited improved cell viabilities, enhanced cell proliferation and migration abilities of both extracts. While heat stress data revealed that PV-E (2.5 μg/ml) and TF-E (5 μg/ml) pretreatment significantly ameliorated effects of thermal-injuries in hASCs as depicted by significantly enhanced cell viabilities, low LDH release profile, and lower annexin-V expression and regulated gene expression of the pretreated cells. ConclusionPV-E and TF-E priming effectively enabled hASCs to combat thermal injury by significantly promoting cell survival than untreated cells. Hence, these findings suggest that PV-E and TF-E priming could be used to attain improved cellular responses and enhanced therapeutic efficacy in burnt tissue.

Cryoprotective effect of wheat starch granular surface proteins on frozen HMW and LMW glutenins: Structure, property and functionality across length scales

Although frozen dough technology has demonstrated significant benefits, the mechanisms underlying dough deterioration during freezing remain unclear. To overcome this obstacle, the effect of freezing-induced deteriorations of wheat starch granular surface proteins (SGSPs)-high/low molecular weight (HMW/LMW) glutenins complexes were analyzed from the molecular to macroscopic scales. After 7 cycles of freezing/thawing treatment, SGSPs-LMW complex showed a higher antifreeze stability than SGSPs-HMW complex. The freezable water content of SGSPs-HMW increased from 32 % to 39 %, indicating a marked migration and recrystallization of ice. In this situation, the interactions of SGSPs-HMW complex were affected and destabilized, leading to partially denatured and depolymerized molecular structures. Furthermore, the bulk protein aggregation network was also dissociated under the ice tearing and splitting, which irreversibly collapsed to small molecular protein particles. In comparison, the resistance of SGSPs-LMW complex on continued network disruption appear to be the key to maintain the quality of frozen dough.

Application of Autologous Platelet-rich Plasma Exerts Cryoprotective Effects on Biological Characteristics of Human Oligoasthenoteratospermia Samples after Freezing and Thawing Procedures.

Platelet-rich plasma (PRP) is enriched with active biological components which showed proliferative and cytoprotective properties in healing different injuries in medicinal fields. This study was designed to assess the cryoprotective effects of autologous PRP on the quality of oligoasthenoteratospermia (OAT) samples during freezing and thawing procedure. The present study is an experimental research. Twenty OAT semen samples were obtained from individuals and prepared by discontinuous density - gradients technique DGC). The control group is sperm samples after DGC. After the procedure, the specimen was divided into four groups. The Freeze group which has no additive and the other three groups were cryopreserved with different concentrations of PRP (1×105/ μL, 0.5×105/μL and 0.25×105/μL). Autologous PRP was provided by each participant. After thawing, sperm parameters, DNA fragmentation by sperm chromatin dispersion test (SCD), protamine deficiency by (Chromomycin A3) CMA3 staining, acrosome integrity and malondialdehyde (MDA) level were evaluated. Cryopreservation resulted in a significant decrease in all factors compared to the control group. There were no significant changes in sperm count, morphology, non-progressive motility and acrosome reaction by adding PRP as a cryoprotectant in comparison with the freeze group. PRP at all three concentrations showed a significant increase in progressive motility (3.05 ± 2.01 vs. 14.05 ± 4.13, 12.35 ± 4.90 and 12.15 ± 9.65, P < 0.001) and viability (36.85 ± 10.25 vs. 47.85 ± 5.86, 51.30 ± 5.54 and 50.05 ± 5.67, P < 0.001) compared to the sperm samples without PRP. The percentage of immotile sperms decreased at all PRP concentrations compared to the freeze group. Moreover, PRP at 1×105/μL concentration showed cryoprotective effects on DNA fragmentation, protamine deficiency and MDA level compared to the other three concentrations. Cryopreservation and thawing procedures may exert adverse effects on biological factors of sperm samples. Therefore, adding PRP as cryoprotectant at all three concentrations especially 1×105/μL can be promising strategy to reduce adverse effects of cryopreservation on OAT samples.

Cryoprotective effect of magnetic field-assisted freezing in combination with curdlan on myofibrillar protein of Litopenaeus vannamei: Oxidative aggregation, protein structure and thermal stability

To counteract the negative effects of conventional freezing methods on frozen surimi products, the present study investigated the effects of magnetic field (MF) freezing in combination with different amounts of curdlan (CUR) on oxidative denaturation, structural alterations, and thermal stability of myofibrillar protein (MP) in shrimp surimi. The results indicated that the intervention of magnetic fields alone improved the quality of frozen muscle proteins. Under the dual intervention of magnetic field-assisted freezing and CUR, small ice crystals formed with MF6 treatment resulted in significantly lower solubility, turbidity, and mean particle size than the control group (p < 0.05). Moreover, the oxidation of MP was also significantly slowed down by inhibiting the formation of hydrophobic groups and carbonyl groups, maintaining a high content of sulfhydryl groups. MF6 also exhibited a high Ca2+-ATPase activity. The α-helix content, the increase in fluorescence intensity under this condition also tend to make the secondary and tertiary structures of myofibrillar protein more stable. Meanwhile, electrophoretic profiles and CLSM showed that this condition maintains the integrity of the MP. In addition, the MF6 samples also had high protein thermal stability. However, excess CUR reduces the excellence of MP cryoprotection. As a result, MF6 has better protection and improvement effects on protein function, structure and thermal stability, and CUR was also found to have the potential for cryoprotectant development.

Effects of sodium carboxymethyl cellulose-tea polyphenols ice coating on the quality degradation of frozen-thawed beef due to changes in protein structure and fat and protein oxidation

During freeze-thaw (FT) cycles, protein structural degradation, lipid and protein oxidation can lead to quality deterioration of beef samples. To address this issue, we developed a cost-effective and easy-to-operate carboxymethyl cellulose sodium-tea polyphenol (CMC-TP) ice coating to inhibit quality deterioration caused by these factors. The beef samples were characterized for various quality attributes, lipid and protein oxidation, and protein structure. The results demonstrated that the CMC-TP ice coating significantly inhibited the deterioration in water-holding capacity (WHC) and tenderness of the beef samples (P < 0.05). Analysis of peroxide value (POV), thiobarbituric acid (TBARS), total volatile basic nitrogen (TVB-N), and carbonyl content revealed that the CMC-TP ice coating significantly suppressed lipid and protein oxidation during FT cycles (P < 0.05). Additionally, assessments of total sulfhydryl content, fluorescence intensity, and surface hydrophobicity indicated that the CMC-TP ice coating effectively mitigated protein structural degradation through antioxidant and cryoprotective effects (P < 0.05). Therefore, the CMC-TP ice coating can enhance the FT stability of beef.

Insight into the cryoprotective effect of egg yolk peptides on frozen egg yolk: functional, structural and physicochemical properties

Insight into the cryoprotective effect of egg yolk peptides on frozen egg yolk: functional, structural and physicochemical properties

Model-Based Optimization of Solid-Supported Micro-Hotplates for Microfluidic Cryofixation.

Cryofixation by ultra-rapid freezing is widely regarded as the gold standard for preserving cell structure without artefacts for electron microscopy. However, conventional cryofixation technologies are not compatible with live imaging, making it difficult to capture dynamic cellular processes at a precise time. To overcome this limitation, we recently introduced a new technology, called microfluidic cryofixation. The principle is based on micro-hotplates counter-cooled with liquid nitrogen. While the power is on, the sample inside a foil-embedded microchannel on top of the micro-hotplate is kept warm. When the heater is turned off, the thermal energy is drained rapidly and the sample freezes. While this principle has been demonstrated experimentally with small samples (<0.5 mm2), there is an important trade-off between the attainable cooling rate, sample size, and heater power. Here, we elucidate these connections by theoretical modeling and by measurements. Our findings show that cooling rates of 106 K s-1, which are required for the vitrification of pure water, can theoretically be attained in samples up to ∼1 mm wide and 5 μm thick by using diamond substrates. If a heat sink made of silicon or copper is used, the maximum thickness for the same cooling rate is reduced to ∼3 μm. Importantly, cooling rates of 104 K s-1 to 105 K s-1 can theoretically be attained for samples of arbitrary area. Such rates are sufficient for many real biological samples due to the natural cryoprotective effect of the cytosol. Thus, we expect that the vitrification of millimeter-scale specimens with thicknesses in the 10 μm range should be possible using micro-hotplate-based microfluidic cryofixation technology.

Synergistic cryoprotective effect of deaeration and polysorbate 80 on IgG denaturation during thin-film freeze-drying

Polysorbate 80 (PS80) is employed as a cryoprotectant in biotherapeutic formulations to preserve biologics from denaturation during the freezing process. However, excessive quantities of PS80 can lead to stickiness in dry powder, thereby reducing production yields and altering the physical and aerodynamic characteristics of the powder. Additionally, degradation byproducts of PS80 pose a risk of destabilizing proteins in therapeutic formulations. Our study reveals the synergistic cryoprotective effect of combining deaeration with PS80. PS80 plays a protective role by competitively binding to ice/water and air/water interfaces, as well as binding directly to IgG molecules. Deaeration increases the cryoprotective effect of PS80 by reducing the surface area of air microbubbles, thereby reducing the required amount of PS80 for surface coverage and limiting available adsorption sites for IgG molecules, which allows the decrease in the necessary concentration of PS80 required to minimize IgG denaturation during the thin-film freeze-drying (TFFD) process. Even at a low concentration of 0.0025 % w/v, PS80 prevents the aggregation of IgG during the freezing step of TFFD but does not eliminate IgG denaturation during the drying step. PS80 concentrations ranging from 0.0025 % to 0.0400 % w/v exhibit no impact on the specific surface area (SSA) and aerodynamic properties (i.e., fine particle fraction (FPF), mass median aerodynamic diameter (MMAD)) of IgG dry powders. These IgG TFFD powders exhibit a fine particle fraction exceeding 70 % and a median mass aerodynamic diameter of approximately 2.3–2.5 μm, with an SSA of around 20 m2/g.

Analysis of the morphology of Sus scrofa domesticus oocyte-cumulus complexes exposed to low and ultra-low temperatures

Relevance. The priority task of reproductive technologies in animal husbandry is the development of effective storage protocols for female gametes. One way to preserve gametes is vitrification, which reduces damage to intracellular organelles by increasing viscosity upon cooling and minimizing crystallization.Methods. Various additives to cryoprotectants are used for optimization. In our work, titanium tetrapolyethylene glycolate was used in a 10-fold molar excess of polyethylene glycol (TTPEG*10PEG), the nature of the effect of which on cells was studied during short-term storage at low (5 °С) and ultra-low temperatures (-196 °С).The purpose of the study is a comprehensive analysis of the morphology of gametes and somatic cells (cumulus) of ovarian follicles of pigs after exposure to low and ultra-low temperatures (vitrification) when included in the TTPEG*10PEG low-temperature storage and vitrification protocol.Results. Exposure to TTPEG*10PEG at 5 °С caused an increase in the level of oocytes with subsequent morphological degenerations in points with control (from 13% to 5%, р = 0.005). After vitrification with TTPEG*10PEG: the level of gametes with low cumulus cells expansion increased to 35% in terms of the proportion of control gametes (23%); the proportion of denudated gametes was reduced to 50% compared to the control 65% (р &lt; 0.05); the level of morphologically degenerated gametes corresponded to that of native oocytes (8% each) and was lower than in the control (17%), р &lt; 0.005. The obtained data indicate the protective and cryoprotective effects of TTPEG*10PEG at a concentration of 2%, which suggests the possibility of its use in the technology of intraovarian vitrification of female reproductive cells.

Instability of natural deep eutectic solvents (NADESs) induced by Amadori rearrangement and its effects on cryopreservation of yeast cells

Natural deep eutectic solvents (NADESs) showing higher cryoprotective effects are attracting concerns, because during the storage, system browning always occurs in aldose/amino acid-based NADESs, which generated brown substances remarkably weaken the cryoprotective effects. In this study, proline/glucose-based (PG) and proline/sorbitol-based (PS) NADESs were prepared, of which storage stability, browning profile, brown substance, and cryoprotective effects were investigated. Results showed that PG at molar ratios of 1:1, 2:1, and 3:1, as well as PS at 1:1, and 2:1 can form NADESs, among which only the PG-based ones could get browning after storage. The predominant brown substance was identified as 1-deoxy-1-L-proline-d-fructose (C11H19O7N, 278 m/z), which was subsequently verified to show cytotoxicity and decrease Saccharomyces cerevisiae cells viability after cryopreservation, suggesting that the brown substance could take a negative effect on cryopreservation. This study may help to attract more concerns to the storage and cryopreservation stabilities of the NADESs in food-related applications.

Enhancing freeze-thaw stability of frozen dough with deacetylated konjac glucomannan: The role of degree of deacetylation

The effect of different degrees of deacetylation (DDs) of deacetylated konjac glucomannan (DKGM) on the gluten structure, water state, and yeast activity of frozen dough was evaluated. The moderate DKGM group maintained a more continuous gluten network after three freeze-thaw cycles, as evidenced by an 8.67% increase in disulfide bond content and a 15.01% increase in α-helix content compared to the KGM group. DKGM effectively impeded bound water migration, with the moderate DKGM group retaining 8.28% more bound water than the KGM group after three freeze-thaw cycles. The stabilization of gluten structure and water state in frozen dough by DKGM resulted in higher yeast activity in the low and moderate deacetylation groups (DD = 31.31% and 50.24%). Additionally, DKGM enhanced the quality of frozen steamed bread. The results indicate that DKGM with a moderate DD (50.24%) effectively alleviates the quality deterioration of frozen dough. These findings suggest that DKGM has great potential as a novel cryoprotectant for frozen dough, with DD being a crucial factor in its cryoprotective effect.

Oxidative regulation and cytoprotective effects of γ-polyglutamic acid on surimi sol subjected to freeze-thaw process

Frozen surimi sol incline to protein oxidation, but the quality control strategies based on oxidation remain limited. Hence, the antioxidant and cryoprotective effects of γ-polyglutamic acid (γ-PGA) on freeze-thawed salt-dissolved myofibrillar protein (MP) sol were investigated. Results showed that γ-PGA could effectively regulate protein oxidation of MP sol during freeze-thawing with lower carbonyl contents and less oxidative cross-linking. Meanwhile, γ-PGA primely maintained sol protein structures, showing reduction of 15.28% of salt soluble protein contents at γ-PGA addition of 0.04% under unoxidized condition. Additionally, compared to the control group without oxidation treatment, cooking loss of heat-induced gel with 0.04% γ-PGA decreased by 47.19%, while gel strength obviously increased by 57.22% respectively. Overall, moderate γ-PGA addition (0.04%) could inhibit protein oxidation of sol, further improving frozen stability of sol through hydrogen bonds and hydrophobic interaction, but excessive γ-PGA was adverse to sol quality due to severe cross-linking between γ-PGA and MP.

Trehalose, Glycerol and Dimethyl Sulfoxide Supplementation for Cryopreservation Media of Honey Bee Drone Semen

The cryogenic storage of honey bee drone (Apis mellifera) semen is a rapidly developing practice, driven by the need to preserve bee colonies and the decline in gamete quality following cryopreservation. Advances in cryobiology, coupled with procedural refinements and the development of new methods for cryopreservation of male gametes at different temperatures, provide promising results for improving drone semen preservation. Innovative strategies involve the incorporation of additives within preservation media to enhance important spermatozoa parameters. Our study aimed to assess the effectiveness of cryoprotectants (CPAs), namely trehalose, glycerol, and dimethyl sulfoxide (DMSO), on the motion characteristics of honey bee drone sperm cells during cryopreservation and subsequent thawing. Using Sperm Class Analyzer (SCA) and Computer-Assisted Sperm Analysis (CASA), we evaluated the impact of these supplements on sperm motility and kinetic parameters. Our findings indicated significant differences in sperm motility (non-progressiveness and progressiveness) and kinetics (curvilinear velocity and linearity) across treatments with trehalose, DMSO, and glycerol. Trehalose supplementation retained significantly higher percentages of sperm motility and kinetic parameters post-cryopreservation compared to DMSO and glycerol. Nevertheless, despite the utilization of new protocols, media, and supplementation, the results obtained are often unsatisfactory. The research provides valuable information for enhancing the efficacy of cryopreservation media to optimize the successful outcome of honey bee drone spermatozoa storage.