Ice Crystal Morphology Research Articles

Influence of starch on freeze-thaw stability of Hypophthalmichthys molitrix surimi gel observed via ice crystal distribution and gel properties

Starch has been recognized as a vital ingredient in surimi products due to its ability to absorb water, which reduces the deterioration of gels and water loss during freezing and thawing. However, it is essential to ascertain the role of starch in the formation of ice crystals and the texture of surimi gels. The impact of freeze-thaw cycles on the morphology and distribution of ice crystals, as well as the textural characteristics of gelatinized and ungelatinized starch-surimi gels was investigated. The results of light microscopy revealed that the presence of starch, irrespective of whether it was gelatinized, resulted in a reduction in the size of ice crystals within the surimi gel network during the freeze-thaw process. In addition, starch in surimi gels was subjected to freeze-thaw cycles, resulting in the emergence of two distinct states of bound water (0.1–1 ms and 1–10 ms). The higher relative content of immobile water indicated that the gelatinized starch had improved water holding properties. Furthermore, the incorporation of gelatinized starch into surimi enhanced its freeze-thaw stability and retarded the loss of gel strength, hardness, and whiteness. The addition of starch had a synergistic impact, enhancing the gel properties by affecting the formation of ice crystals and water absorption.

Frozen dough steamed products: Deterioration mechanism, processing technology, and improvement strategies.

Fresh dough products lead to instability in product quality, high production costs, and more production time, which seriously affects the industrial production of the food industry. The frozen dough technology mitigates the problems of short shelf-life and easy deterioration of quality during storage and transportation. It has shown a series of advantages in large-scale industrialization, high-quality standardization, and chain operation. However, the further development of frozen dough is restricted by the deterioration of the main components (gluten, starch, and yeast) caused by freezing. This review summarizes the main production process of frozen steamed bread and buns, and the deterioration reasons for the main component of frozen dough. The improvement mechanisms of raw ingredients, processing technology, processing equipment, and additives on frozen dough quality were analyzed from the perspective of improving gluten network integrity and yeast freeze tolerance. From prefermented frozen raw to steamed products without thawing has become the preferred production process to improve production efficiency. Wheat flour mixed with other flour can maintain the gluten network continuity of frozen dough. The freeze tolerance of yeast was improved by treatment with yeast suspension, yeast cell encapsulation, screening hybridization, and genetic engineering. Process optimization and new technology-assisted fermentation and freezing effectively reduce freezing damage. Various additives improve the freeze resistance of the gluten-starch matrix by promoting protein cross-linking and inhibiting water migration. In addition, ice structural proteins and ice nucleating agents have been proven to change the growth morphology and formation temperature of ice crystals. More new technologies and additive synergies need to be further explored.

Experimental and numerical study on single ice crystal growth of deionized water and 0.9 % NaCl solution under static magnetic field

Ice crystal growth of water and its aqueous solution is the key phenomenon in food freezing. In this research, the effect of static magnetic field (SMF) on single ice crystal growth was investigated combing experiment and simulation. The ice crystal growth of water and NaCl-water solution under 0 - 15 mT SMF intensities were studied. The UV absorbance of water after SMF treatment was measured. Phase field model was adopted to simulate the ice crystal growth. The results show that SMF significantly inhibited the growth rate, while had little effect on the morphology and growth direction of ice crystals. SMF had a certain enhancement effect on the UV absorbance of deionized water. The proposed model could well simulate the ice crystal growth under different SMF intensities. Combining experimental and simulation results, it can be inferred that SMF inhibits ice crystal growth by enhancing original hydrogen bonds and reducing free energy.

The influence of pressure-shift freezing based on the supercooling and pressure parameters on the freshwater surimi gel characteristics

In this study, the phase transition curve of grass carp surimi gel in the ice I region was mapped and fitted. Additionally, the average adiabatic compressibility of surimi gel was calculated to be 2.7℃/100 MPa in the range of 0–320 MPa. Building upon this, the study further investigated the impact of pressure-shift freezing (PSF) treatment based on supercooling and pressure coupling on the gel strength, texture profile analysis (TPA), and water-holding capacity of surimi gel. Compared with the low level of supercooling (supercooling value > -15℃) treatment, the PSF treatment with a higher supercooling degree (supercooling value ≤ -15℃) could enhance the strength and water-holding capacity of surimi gel. The morphology and distribution of ice crystals suggested that the diameter and size distribution of ice crystals in the sample were dependent on the combination of pressure level and supercooling. The combination of precise control of supercooling and pressure parameters is beneficial in improving the mechanical properties and water-holding capacity of surimi gel. This is of great value for developing high-quality surimi gel products and also offers a new research thread in the realm of high-pressure freezing.

Effect of temperature fluctuations during frozen storage on ice crystal distribution and quality of tilapia (Oreochromis mossambicus)

The study constructed a model of temperature fluctuation (TF, −20 °C ∼ -10 °C) during frozen status to build a link between the tilapia fillets muscle of ice crystal morphology, moisture distribution, protein oxidation index and the edible quality. When TF treatment more than 3 times, the brightness, color and hardness of frozen tilapia fillets decreased significantly, and the cooking loss and thawing loss increased significantly. The free and unconjugated water in frozen fish fillets exceeded 97 % and did not change much after 9 times TF. The K and TVB-N values were within the safety standards (K < 60 %, TVB-N < 30 mg N/100 g). The ice crystals in the tissues were significantly increased. Protein carbonyls and Ca2+-ATPase were significantly reduced, and secondary structures were irregular. Network correlation analysis showed that ice crystal morphology was significantly correlated with the color, texture and protein oxidation index of frozen tilapia fillets. The results would provide theoretical approach for the transportation and sales of tilapia industrial enterprises.

Basic Theory of Ice Crystallization Based on Water Molecular Structure and Ice Structure.

Freezing storage is the most common method of food preservation and the formation of ice crystals during freezing has an important impact on food quality. The water molecular structure, mechanism of ice crystal formation, and ice crystal structure are elaborated in the present review. Meanwhile the methods of ice crystal characterization are outlined. It is concluded that the distribution of the water molecule cluster structure during the crystallization process directly affects the formed ice crystals' structure, but the intrinsic relationship needs to be further investigated. The morphology and distribution of ice crystals can be observed by experimental methods while simulation methods provide the possibility to study the molecular structure changes in water and ice crystals. It is hoped that this review will provide more information about ice crystallization and promote the control of ice crystals in frozen foods.

Insights into the potential mechanism of diversified freezing techniques' influence on quality of golden pompano (Trachinotus ovatus): Focus on freezing speed, ice crystal morphology, water migration, and texture properties

The influences of air freezing (AF), liquid nitrogen freezing (LNF), immersion freezing (IF), magnetic field-assisted immersion freezing (MIF), and ultrasound-assisted immersion freezing (UIF) on the freezing time, water holding capacity, texture profile analysis (TPA), and microstructure of the golden pompano (Trachinotus ovatus) muscle was investigated. The findings indicated that the MIF and UIF groups were more effective in reducing the freezing time than other freezing method, with 84.35% and 85.81% shorter than that of AF, respectively. Among all the treatments, MIF had the best muscle integrity and closely packed myogenic fibers, which were more beneficial for maintaining the water holding capacity, textural properties, and color of the golden pompano muscle. Among all the groups, the MIF quality was the closest to unfrozen samples. Therefore, MIF effectively reduced the size of ice crystals, and inhibited the quality deterioration of frozen golden pompano.

Porous silicate cement membrane: Unraveling the effect of triethanolamine on ice crystal changing, pore structure, and performance

Triethanolamine (TEA) has been broadly used as the organic amine conditioning agent to modify the workability of cement-based materials. However, the effect of TEA on the structure and property of porous silicate cement membranes has not been reported. In this paper, TEA was applied to study its effect on parameters of porous silicate cement membranes based on the preparation method combining freeze casting and heat-dry curing, because it is easy to form complexes with cement particles. The effect and acting mechanism of TEA on porous silicate cement membranes were researched using a series of characterizations and molecular dynamics (MD) simulation. Results showed that TEA significantly improved the performance of porous silicate cement membranes. The addition of TEA changed the pore morphology of porous silicate cement membranes from lamellar structures to cellular structures, with mesoporous size distribution focusing on 2.5–4.5 nm at TEA doping ratio of 0.16 wt%. The oil-water separation performance could reach up to 99.6 %. Through comprehensive comparison, the porous silicate cement membrane with 1.0 wt% TEA showed better holistic preponderance of oil-water separation and permeation flux. Quantum chemistry calculation and MD simulation were used to briefly explain the influence of TEA on phase transformation. MD showed that adding TEA changed the morphology and structure of ice crystals. The percentage of the Ih structure significantly increased from 53 % to 86 % after adding TEA. This study might expand the application of TEA in other aspects and enlighten relevant workers in new experimental designs.

Multi‐Scale Ice Inhibition Platform Enables Full‐Cycle Cryogenic Protection for Mouse Oocyte

AbstractCryopreservation of metaphase II (MII) oocytes is crucial to preserve female fertility. However, the existing vitrification technology just provides partial cryogenic protection for oocytes and must use high concentrations of toxic penetrating cryoprotective agents (CPAs, up to 4.8 M). Here, a multi‐scale ice inhibition platform is proposed, which effectively suppresses ice crystal morphology, ice recrystallization (IR), temperature gradient, and devitrification. This platform achieves mouse oocyte survival rate of 98.6% using the low concentration of CPA (3.1 M) while also possessing batch oocyte cryopreservation ability. In contrast, recovered oocytes show a much more modest variation of genes compared with the conventional method (85 vs. 1396 genes), retaining normal fertilization, embryonic development, and birth to healthy offspring. Diverging from the conventional vitrification method with partial cryogenic protection capability, this platform introduces full‐cycle ice inhibition, offering promising prospects for achieving high‐quality and scalable fertility preservation.

Effects of high voltage electrostatic field assisted freezing enhanced with ultrahigh permittivity ceramic on quality attributes of grass carp (Ctenopharyngodon idella) fillets during frozen storage

Small sample capacity is a critical limitation for the industrialization of the high voltage electrostatic field assisted freezing (HVEFF) technique. In this study, using grass carp as a sample, the effects of ultrahigh permittivity ceramic enhanced HVEFF system on the quality attributes of grass carp (Ctenopharyngodon idella) fillets during freezing and frozen storage were investigated. The appropriate electrostatic field strength for freezing grass carp fillets was determined first with the HVEFF Peltier cooling platform and then used for the freezing and frozen storage of grass carp fillets in an HVEFF refrigerator at −18 °C. The biochemical qualities, and ice crystal morphology of the samples were measured every 2, 4, 6, and 8 weeks during frozen storage. Compared to the frozen control, this novel HVEFF system could effectively delay the deterioration of texture and water migration, and reduce TVB-N, TBARS and the equivalent ice crystal diameters. This study not only showed the positive effect of this novel HVEEF system on the frozen preservation of grass carp fillets but more importantly provided a solution to the bottleneck of HVEFF industrialization.

Novel Apoplastic Antifreeze Proteins of Deschampsia antarctica as Enhancer of Common Cell Freezing Media for Cryobanking of Genetic Resources, a Preliminary Study.

Antifreeze proteins (AFPs) are natural biomolecules found in cold-adapted organisms that lower the freezing point of water, allowing survival in icy conditions. These proteins have the potential to improve cryopreservation techniques by enhancing the quality of genetic material postthaw. Deschampsia antarctica, a freezing-tolerant plant, possesses AFPs and is a promising candidate for cryopreservation applications. In this study, we investigated the cryoprotective properties of AFPs from D. antarctica extracts on Atlantic salmon spermatozoa. Apoplastic extracts were used to determine ice recrystallization inhibition (IRI), thermal hysteresis (TH) activities and ice crystal morphology. Spermatozoa were cryopreserved using a standard cryoprotectant medium (C+) and three alternative media supplemented with apoplastic extracts. Flow cytometry was employed to measure plasma membrane integrity (PMI) and mitochondrial membrane potential (MMP) postthaw. Results showed that a low concentration of AFPs (0.05 mg/mL) provided significant IRI activity. Apoplastic extracts from D. antarctica demonstrated a cryoprotective effect on salmon spermatozoa, with PMI comparable to the standard medium. Moreover, samples treated with apoplastic extracts exhibited a higher percentage of cells with high MMP. These findings represent the first and preliminary report that suggests that AFPs derived from apoplastic extracts of D. antarctica have the potential to serve as cryoprotectants and could allow the development of novel freezing media.

Recent advances, challenges and functional applications of antifreeze protein in food industry

SummaryFreezing is a common food preservation method that can extend the shelf life of food, but the ice crystals and recrystallisation during freezing, storage and transportation cause significant damage to frozen food. Antifreeze proteins are a class of proteins that widely exist in organisms living in cold conditions, such as fish, insects, plants and microorganisms in Antarctica and other cold regions. Antifreeze proteins can reduce the freezing point of water, inhibit recrystallisation effects, modify ice crystal morphology and effectively suppress the quality deterioration caused by ice crystals during food freezing. This review comprehensively introduces the source, antifreeze mechanism, application in food, influencing factors and regulating methods of antifreeze activity of antifreeze proteins, as well as the limitations of antifreeze proteins. It also looks forward to the future application of antifreeze proteins in food.

Brassica juncea leaf cuticle contains xylose and mannose (xylomannan) which inhibit ice recrystallization on the leaf surface.

Conjugated sugars showed antifreeze activity in the cuticle by ice recrystallization inhibition rather than thermal hysteresis, enhancing freezing capacity at the surface of B. juncea leaves. Antifreeze biomolecules play a crucial role in mitigating the physical damage from frost by controlling extracellular ice crystal growth in plants. Antifreeze proteins (AFPs) are reported from the apoplast of different plants. Interestingly, there is no report about antifreeze properties of the cuticle. Here, we report the potential antifreeze activity in the Brassica juncea (BJ) leaf cuticle. Nano LC-MS/MS analysis of a cuticle protein enriched fraction (CPE) predicted over 30 putative AFPs using CryoProtect server and literature survey. Ice crystal morphology (ICM) and ice recrystallization inhibition (IRI) analysis of ABC supernatant showed heat and pronase-resistant, non-protein antifreeze activities as well as hexagonal ice crystals with TH of 0.17°C and IRI 46%. The ZipTip processed ABC supernatant (without peptides) had no effect on TH activity, confirming a non-protein antifreeze molecule contributing to activity. To understand the origin and to confirm the source of antifreeze activity, cuticular membranes were isolated by pectinase and cellulase hydrolysis. FTIR analysis of the intact cuticle showed xylose, mannose, cellulose, and glucose. Xylanase and cellulase treatments of the ZipTip processed ABC supernatant led to an increase in sugar content and 50% loss in antifreeze activity. UV spectroscopy and NMR analysis supported the finding of FTIR and enzyme hydrolysis suggesting the contribution of xylose and mannose to antifreeze activity. By TLC analysis, conjugated sugars were found in the cuticle. This work has opened up a new research area where the antifreeze capacity needs to be established with regard to complete characterization and mechanism of action of the antifreeze carbohydrates (conjugated sugars) on the leaf surface.

Effect of multi-frequency ultrasound-assisted immersion freezing on quality changes in large yellow croaker (Larimichthys crocea) during frozen storage

The effects of multi-frequency ultrasound-assisted immersion freezing (MUIF) at different ultrasound power levels (160, 175, and 190 W, respectively) on the quality of large yellow croaker (Larimichthys crocea) during frozen storage were studied. The study found that water loss and texture deterioration of MUIF were lower and MUIF was fresher than immersed freezing (IF) by affecting the morphology of ice crystals. Although the total volatile basic nitrogen (TVB-N) and K values of each treatment increased continuously during frozen storage, MUIF was consistently lower than IF. Among them, MUIF at 175 W (MUIF-175) maintained good quality in frozen storage because of the fine and uniform ice crystals, indicating that MUIF at a specific power level can reduce the quality degradation of the samples during frozen storage.

The microscopic contact morphology of ice crystal on substrate and its effect on heterogeneous nucleation/icing

As one of the long-standing crucial theoretical assumptions of the heterogeneous nucleation and substrate icing theory, the tiny shape of an ice tip on the substrate commands further detailed experimental observation. In this paper, the morphology and growth processes of ice on different near-thermal insulation surfaces at a low supercooling degree were observed by microscope. Experimental results show that the contact angles of the dendritic ice tip on the substrates are all obtuse under a lower supercooling degree, and decrease with temperature as a Sigmoid function. Moreover, the analysis of ice growth on different substrates reveals that the surface property can affect substrate icing by altering the ice tip; that is, as the ice contact angle increases, the radius will increase and the influence of the thermal conduction of substrate on the ice tip will decrease, ultimately leading to a slower growth rate. Significantly, heterogeneous nucleation experiments illustrate that the obtained ice contact angle is close to the ice nucleus contact angle. Consequently, compared with previous theories, the temperature-dependent ice contact angle could be used to accurately predict the nucleation rate and ice growth.

Changes in the quality of apple tissue subjected to different freezing rates during long-term frozen storage at different temperatures

In this manuscript, the impact of various parameters including freezing rate, storage temperature and duration on the quality of apples is reported. Freezing rate significantly affected the quality attributes (firmness, drip loss, and morphology of ice crystals). Significant difference in the firmness loss was seen between the static freezing (SF at -18 °C) and rapid freezing (RF at -40 °C and 2 m/s air velocity) and ultra rapid freezing (URF at -72 °C and 1 m/s air velocity) samples on day 0. Regarding drip loss, significant difference could only be seen between SF and URF conditions. Nevertheless, microscopy results showed that ice crystal size reduced with the increase in the freezing rates. Storage of frozen products at two different temperatures (i.e. -12 °C and -18 °C) for 90 days caused serious damage to the product. Whatever the freezing condition and storage temperature, the maximum reduction in firmness happened during the first 30 days of storage. A maximum reduction (85%) in the texture was seen for SF samples stored for 30 days at -12 °C compared to fresh samples. On the other hand, drip loss increased gradually with the storage period for all freezing methods and storage temperatures. After 90 days, SF samples stored at -12 °C recorded the highest drip loss (6.12%), while RF samples stored at -18 °C exhibited the lowest value (5.05%). MANOVA analysis revealed that all three independent variables (i.e. freezing rate, storage time, and storage temperature) significantly affected the drip loss and texture. Lastly, microscopy after 90 days showed a high degree of tissue damage, making it difficult to differentiate the freezing method and storage temperature.

Modulation of ice crystal formation behavior in pectin-sucrose hydrogel by freezing temperature: Effect on ice crystal morphology and drying properties

A model solid food system was designed to investigate the effects of freezing temperature on freezing rate, ice crystal morphology, physical properties, and drying characteristics of freeze-dried pectin cryogels. The results indicated that the fractal dimension of ice crystals was significantly reduced in gels while the mean diameter and the diameter range tended to increase as the freezing rate accelerated. The drying time is positively correlated with the fractal dimension and negatively correlated with the proportion and the mean diameter of the ice crystal. Slow freezing (at 20 °C) produced large ice crystals (0.3 mm) with a low fractal dimension (1.662), resulting in a short drying time (9.46 h) and low hardness (max positive force and positive area were 436.69 g and 717.79 g mm, respectively). This study provides reference data that could help increase freeze-drying efficiency and improve the texture quality of food products.

Real-time observation of the freezing stage of the mannitol solution using high-resolution optical microscopy

Vacuum freeze-drying has been expanding its influence in many fields, and the freezing stage is of utmost importance for the freeze-drying process. However, the limited understanding of the freezing stage has posed a major challenge for developing the vacuum freeze-drying process. An experimental setup was designed and employed in this paper to experimentally investigate the freezing stage of the mannitol solution. The cooling rate and solute mass fraction are chosen as the key freezing parameters. The nucleation temperature, the morphology and velocity of the freezing front, the morphology and size distribution of the ice crystals at the combination of different freezing conditions were studied. The results show that the nucleation temperature (supercooling degree) distribution could be better described by the Gauss distribution. The morphology of the freezing front is more strongly affected by the cooling rate compared with the mass fraction. In addition, the morphology of ice crystals also exhibits differences under different freezing conditions. The average size decreases with the increase of the cooling rate, while the uniformity of particle size distribution increases when increasing the cooling rate. The research could help deepen the understanding of the freezing stage in a qualitative way, and provide a reference for the theoretical research.

Toward Better Constrained Scattering Models for Natural Ice Crystals in the Visible Region

AbstractIn this work, we introduce a method for constraining the optical scattering models of natural ice crystals based on in‐situ measurements. Specifically the measured angular scattering functions for ice crystals can be used to compute a set of the asymmetry parameter (g) and the corresponding complexity parameter (Cp). It is demonstrated that the g‐Cp relation can give valuable information on the morphology of ice crystal. The validity of the methods is shown from theoretical perspectives and the geometric‐optics ray‐tracing simulations. As an application, we investigate rimed ice crystals from in‐situ measurements and found that (a) the Cp parameter is very well correlated with the surface riming degree and (b) only those models with both roughness and internal scattering can explain the observed g‐Cp relation for rimed particles.

Visualization of cold surface frosting

The frosting has a profound impact on heat transfer. The surface frosting makes heat transfer difficult and reduces heat transfer efficiency. Therefore, it is particularly important to study anti freezing methods and measures. In this paper, based on the constant temperature and humidity visualization system, the freezing process and frosting process of water droplets on the bare aluminium surface, hydrophilic coating surface, and hydrophobic coating surface were observed by Rising View and MATLAB. The thickness of frost, the freezing radius of water droplets, the morphology of ice crystals, and the coverage rate of water droplets were compared. Finally, the effect of different coatings on inhibiting frosting was analysed quantitatively and theoretically.