scholarly journals A Review of the Material Characteristics, Antifreeze Mechanisms, and Applications of Cryoprotectants (CPAs)

2021 ◽  
Vol 2021 ◽  
pp. 1-14
Author(s):  
Xiangjian Liu ◽  
Yuxin Pan ◽  
Fenglin Liu ◽  
Yongju He ◽  
Qubo Zhu ◽  
...  
Keyword(s):  
Cell Membranes ◽  
Freezing Point ◽  
Medical Science ◽  
Food Preservation ◽  
Ice Crystals ◽  
Freezing Process ◽  
Cell Protection ◽  
Surface Hydrogen ◽  
Ice Surface ◽  
Material Characteristics

Cryopreservation has been a key technology in medical science, food preservation, and many other fields. In a freezing process, the formation of ice crystals may cause significant damage to the frozen samples. In order to reduce the damage, many cryoprotectants (CPAs) have been developed and added in cryopreservation processes for reduced ice volume, decreased ice size, proper ice shaping, and cell protection. According to the material characteristics, the CPAs are either impermeable (i.e., antifreeze protein, polyampholytes, and polyvinyl alcohol) or permeable (i.e., dimethyl sulfoxide, proline, and glycerol) to cell membranes. The typical CPAs are introduced in this work with their material characteristics, antifreeze mechanisms, and applications. Antifreeze mechanisms for different CPAs involve molecular adsorption on the ice surface, hydrogen bonding to ice, bending the ice surface, lowering the freezing point, inhibiting ice recrystallization, protecting cell membranes, reducing dehydration of cells, and breaking hydrogen bonds among ice crystals to reduce the size of ice crystals. In practice, different CPAs can be used together with their cryopreservation properties functioning synergetically. This study reviews the recent applications of CPAs in food, biology and medicine, and agriculture. Future works for CPAs are suggested in improving efficiency, revealing mechanisms, broadening application, and finding new CPAs.

scholarly journals The Formation and Control of Ice Crystal and Its Impact on the Quality of Frozen Aquatic Products: A Review

Crystals ◽  
2021 ◽  
Vol 11 (1) ◽  
pp. 68
Author(s):  
Mingtang Tan ◽  
Jun Mei ◽  
Jing Xie
Keyword(s):  
Product Quality ◽  
Freezing Point ◽  
Ice Crystals ◽  
Affecting Factors ◽  
Frozen Food ◽  
Aquatic Products ◽  
Size Number ◽  
Underlying Mechanisms ◽  
And Control ◽  
Ice Crystallization

Although freezing has been used to delay the deterioration of product quality and extend its shelf life, the formation of ice crystals inevitably destroys product quality. This comprehensive review describes detailed information on the effects of ice crystals on aquatic products during freezing storage. The affecting factors (including nucleation temperature, freezing point, freezing rate, and temperature fluctuation) on the size, number, distribution, and shape of ice crystals are also elaborated in detail. Meanwhile, the corresponding technologies to control ice crystals have been developed based on these affecting factors to control the formation of ice crystals by inhibiting or inducing ice crystallization. In addition, the effects of ice crystals on the water, texture, and protein of aquatic products are comprehensively discussed, and the paper tries to describe their underlying mechanisms. This review can provide an understanding of ice crystallization in the aquatic products during freezing and contribute more clues for maintaining frozen food quality.

Physical processes behind interactions of microplastic particles with ice

2021 ◽  
Author(s):  
Irina Chubarenko
Keyword(s):  
Laboratory Tests ◽  
Freezing Point ◽  
Ice Cores ◽  
Russian Science ◽  
Density Maximum ◽  
Freshwater Ice ◽  
Ice Surface ◽  
Strong Convection ◽  
The Difference ◽  
Negatively Buoyant

<p>Microplastic particles (MPs) are found in marine ice in larger quantities than in seawater, indicating that the ice is an important link in the chain of spreading of this contaminant. Some studies indicate larger MPs abundance near the ice surface, while others did not find any consistent pattern in the vertical distribution of MPs within sea ice cores. We discuss physical mechanisms of incorporation of MPs in the ice and present the results of laboratory tests, underpinning our conclusions.</p><p>First, plastic hydrophobicity is shown to cause the effect of pushing the floating MPs further up of the newly-forming ice. This leads to a concentration of MPs at the ice surface in the laboratory, while in the field the particles at the surface may by covered by snow and become a part of the upper ice layer. Under open-air test conditions, the bubbles of foamed polystyrene (density 0.04 g/cm<sup>3</sup>), initially floating at the water surface, were gone by weak wind when the firm ice was formed.</p><p>Second, the difference between freshwater and marine ice is considered. Since fresh water has its temperature of the density maximum (Tmd=3.98 C) well above the freezing point (Tfr=0 C), the freshwater ice is formed when the water column is stably stratified for a relatively long period of cooling from the Tmd down to the Tfr. Under such steady conditions, even just slightly positively/negatively buoyant MPs have enough time to rise to the surface / to settle to the bottom. In contrast, the ice in the ocean freezes when thermal convection is at work, further enhanced by the brine release. Thus, strong convection beneath the forming marine ice keeps slightly positively/negatively buoyant MPs in suspension and maintains the contact between the MPs and the forming ice. Laboratory tests show both the difference between the solid-and-transparent freshwater ice and the layered, filled with brine marine ice, and the difference in the level of their contamination.</p><p>Lastly, it is demonstrated that MPs tend to be incorporated in the ice together with air bubbles and in-between the ice plates (in brine channels). This is most probably due t plastics’ hydrophobicity.</p><p>Investigations are supported by the Russian Science Foundation, grant No 19-17-00041.</p>

The impact of ι‐ and κ‐carrageenan addition on freezing process and ice crystals structure of strawberry sorbet frozen by various methods

2019 ◽  
Vol 85 (1) ◽  
pp. 50-56 ◽  
Author(s):  
Anna Kamińska‐Dwórznicka ◽  
Agnieszka Janczewska‐Dupczyk ◽  
Anna Kot ◽  
Sylwia Łaba ◽  
Katarzyna Samborska
Keyword(s):  
Ice Crystals ◽  
Freezing Process ◽  
The Impact

scholarly journals Localized Basal Freezing Within George VI Ice Shelf, Antarctica

1988 ◽  
Vol 34 (116) ◽  
pp. 71-77 ◽  
Author(s):  
M. Pedley ◽  
J.G. Paren ◽  
J.R. Potter
Keyword(s):  
Freezing Point ◽  
Saline Water ◽  
Thick Layer ◽  
Ice Shelf ◽  
Low Salinity ◽  
Ice Surface ◽  
Salinity Water ◽  
Basal Melting ◽  
Surface Ice

AbstractHobbs Pool is an area of thin ice shelf situated within George VI Ice Shelf, Antarctica. Thicker ice shelf surrounding Hobbs Pool isolates the upper 155 m of the water column from water lying at the same depth else-where under the ice shelf. Summer melt-water lakes drain through crevasses at Hobbs Pool forming a 155 m thick layer of low-salinity water close to its freezing point. Colder and more saline water in the lower part of this layer leads toin-situfreezing of fresher water lying above it. Below 155 m depth, the water temperature and salinity are linearly related by basal melting which is observed elsewhere under the ice shelf. The surface ice shows areas of deformation and deposits of subglacial rock debris which may result from upward particle paths in the area. The raising of subglacial rock debris on to the ice surface may provide a mechanism for the transport of erratics across the ice shelf to Alexander Island from the base of Palmer Land glaciers.

scholarly journals Phase-Field Modeling of Freeze Concentration of Protein Solutions

Polymers ◽  
2018 ◽  
Vol 11 (1) ◽  
pp. 10 ◽  
Author(s):  
Tai-Hsi Fan ◽  
Ji-Qin Li ◽  
Bruna Minatovicz ◽  
Elizabeth Soha ◽  
Li Sun ◽  
...  
Keyword(s):  
Phase Field ◽  
Liquid Solution ◽  
Solute Concentration ◽  
Ice Crystals ◽  
Mean Field Approximation ◽  
Solution Viscosity ◽  
Bulk Solution ◽  
Freezing Process ◽  
Freeze Concentration ◽  
Solute Exclusion

Bulk solutions of therapeutic proteins are often frozen for long-term storage. During the freezing process, proteins in liquid solution redistribute and segregate in the interstitial space between ice crystals. This is due to solute exclusion from ice crystals, higher viscosity of the concentrated solution, and space confinement between crystals. Such segregation may have a negative impact on the native conformation of protein molecules. To better understand the mechanisms, we developed a phase-field model to describe the growth of ice crystals and the dynamics of freeze concentration at the mesoscale based on mean field approximation of solute concentration and the underlying heat, mass and momentum transport phenomena. The model focuses on evolution of the interfaces between liquid solution and ice crystals, and the degree of solute concentration due to partition, diffusive, and convective effects. The growth of crystals is driven by cooling of the bulk solution, but suppressed by a higher solute concentration due to increase of solution viscosity, decrease of freezing point, and the release of latent heat. The results demonstrate the interplay of solute exclusion, space confinement, heat transfer, coalescence of crystals, and the dynamic formation of narrow gaps between crystals and Plateau border areas along with correlations of thermophysical properties in the supercooled regime.

Temperature gradient osmometer and anomalies in freezing temperatures

1994 ◽  
Vol 267 (6) ◽  
pp. R1646-R1652
Author(s):  
A. Arav ◽  
B. Rubinsky
Keyword(s):  
Amino Acids ◽  
Temperature Gradient ◽  
Cell Membranes ◽  
Organic Molecules ◽  
Thermal Hysteresis ◽  
Freezing Point ◽  
Freezing Temperature ◽  
New Device ◽  
Melting Temperatures ◽  
Temperature Depression

We have developed a new device that measures freezing and melting temperatures in nanoliter volume samples and can be used as a "freezing point osmometer" with a resolution many orders of magnitude greater than that of existing freezing point osmometers. Using this device we found anomalies in the depression of the freezing temperature and thermal hysteresis in aqueous solutions of hydrophilic amino acids, polyamino acids, and lectins. These anomalies would not have been possible to detect with currently used technology. The compounds that produce anomalies in freezing temperature were reported in the literature as having the ability to bind to cell membranes. This suggests a relation between a molecule's ability to bind to cell membranes and its anomalous freezing temperature depression. The new freezing point osmometer and our results could be important for studying and understanding organic molecules and their interaction with membranes and water.

scholarly journals Effect of Type I Antifreeze Proteins on the Freezing and Melting Processes of Cryoprotective Solutions Studied by Site-Directed Spin Labeling Technique

Crystals ◽  
2019 ◽  
Vol 9 (7) ◽  
pp. 352 ◽  
Author(s):  
Adiel F. Perez ◽  
Kyle R. Taing ◽  
Justin C. Quon ◽  
Antonia Flores ◽  
Yong Ba
Keyword(s):  
Freezing Point ◽  
Antifreeze Proteins ◽  
Active Role ◽  
Spin Labeling ◽  
Ice Crystals ◽  
Freezing Injury ◽  
Type I ◽  
Paramagnetic Resonance ◽  
Potential Applications ◽  
Site Directed Spin Labeling

Antifreeze proteins (AFPs) protect organisms living in subzero environments from freezing injury, which render them potential applications for cryopreservation of living cells, organs, and tissues. Cryoprotective agents (CPAs), such as glycerol and propylene glycol, have been used as ingredients to treat cellular tissues and organs to prevent ice crystal’s formation at low temperatures. To assess AFP’s function in CPA solutions, we have the applied site-directed spin labeling technique to a Type I AFP. A two-step process to prevent bulk freezing of the CPA solutions was observed by the cryo-photo microscopy, i.e., (1) thermodynamic freezing point depression by the CPAs; and (2) inhibition to the growth of seed ice crystals by the AFP. Electron paramagnetic resonance (EPR) experiments were also carried out from room temperature to 97 K, and vice versa. The EPR results indicate that the spin labeled AFP bound to ice surfaces, and inhibit the growths of ice through the bulk freezing processes in the CPA solutions. The ice-surface bound AFP in the frozen matrices could also prevent the formation of large ice crystals during the melting processes of the solutions. Our study illustrates that AFPs can play an active role in CPA solutions for cryopreservation applications.

Thermodynamic Theory and Experimental Validation of a Multiphase Isochoric Freezing Process

2019 ◽  
Vol 141 (8) ◽  
Author(s):  
Matthew J. Powell-Palm ◽  
Justin Aruda ◽  
Boris Rubinsky
Keyword(s):  
First Principles ◽  
Experimental Validation ◽  
Freezing Point ◽  
Physiological Saline ◽  
Physiological Solution ◽  
Freezing Process ◽  
Hypertonic Solution ◽  
Chemical Additives ◽  
Biological Matter ◽  
High Concentrations

Freezing of the aqueous solutions that comprise biological materials, such as isotonic physiological saline, results in the formation of ice crystals and the generation of a hypertonic solution, both of which prove deleterious to biological matter. The field of modern cryopreservation, or preservation of biological matter at subfreezing temperatures, emerged from the 1948 discovery that certain chemical additives such as glycerol, known as cryoprotectants, can protect cells from freeze-related damage by depressing the freezing point of water in solution. This gave rise to a slew of important medical applications, from the preservation of sperm and blood cells to the recent preservation of an entire liver, and current cryopreservation protocols thus rely heavily on the use of additive cryoprotectants. However, high concentrations of cryoprotectants themselves prove toxic to cells, and thus there is an ongoing effort to minimize cryoprotectant usage while maintaining protection from ice-related damage. Herein, we conceive from first principles a new, purely thermodynamic method to eliminate ice formation and hypertonicity during the freezing of a physiological solution: multiphase isochoric freezing. We develop a comprehensive thermodynamic model to predict the equilibrium behaviors of multiphase isochoric systems of arbitrary composition and validate these concepts experimentally in a simple device with no moving parts, providing a baseline from which to design tailored cryopreservation protocols using the multiphase isochoric technique.

Freezing Point Determination in Immature Stages of Insects

1964 ◽  
Vol 96 (1-2) ◽  
pp. 158-158 ◽  
Author(s):  
C. R. Sullivan ◽  
G. W. Green
Keyword(s):  
Cold Hardiness ◽  
Freezing Point ◽  
Visual Observation ◽  
Freezing Process ◽  
Immature Stages ◽  
Filter Paper Disc ◽  
Recording Potentiometer ◽  
Binocular Microscope ◽  
The Moment ◽  
Freezing Chamber

Conventional and modified methods of obtaining supercooling points of immature stages of insects have been utilized in studies of the cold-hardiness of the European pine shoot moth and the European pinesawfly. A method has been developed to permit visual observation of the freezing process of more than one specimen at a time. A freezing chamber consisting of a hole one inch in depth and one-half inch in diameter is located in the upper end of an aluminum rod partially submerged in a dry ice-alcohol mixture. A small filter paper disc, used as the insect platform, rests upon a #40 copper-constantan thermocouple located near the base of the freezing chamber. The thermocouple enters the chamber through a hole in the wall after several circuits around the circumference of the rod to prevent temperature anomalies attributable to thermal conduction within the wire. The thermocouple is connected to a sensitive recording potentiometer. The wall of the freezing chamber is blackened to prevent reflection of light from obscuring the view of the freezing process, through a binocular microscope mounted above the freezing chamber. The moment of freezing is readily recorded on the temperature trace provided by the potentiometer. At a cooling rate of approximately 5°F. per minute, a correction factor of 2.5°F. must be added to the indicated freezing point to obtain the actual temperature at the surface of the platform. When this correction is applied, the results provide data applicable to statistical analysis of freezing point determinations.

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