Control of ice crystal nucleation and growth during the food freezing process

Effect of liquid nitrogen spray freezing conditions - temperature, sample volume and exposure depth - on the resulting temperature fluctuation, microstructure, and quality of large yellow croaker fish during frozen storage

The microstructure and physicochemical properties of large yellow croaker (Larimichthys crocea) fish frozen by air freezing (AF, -20 °C) and liquid nitrogen spray freezing (LNSF) at -20, -60, and -100 °C, during frozen storage at -30 °C were evaluated. LNSF at -100 °C resulted in small and uniform ice crystals with a significantly (P < 0.05) lower cross-sectional area (187 μm2) as compared to AF (7844 μm2), thereby better preserving the structure of myofibrils, and reducing the thawing loss from 11.6% to 7.0%. The rate of lipid oxidation and protein degradation significantly decreased with an increasing freezing rate. The effects of sample volume and depth on temperature fluctuations and changes in the ice crystal size were explored based on changes in the ice fraction. The temperature fluctuations decreased from 0.94 to 0.65 °C, and the cross-sectional area decreased from 457 to 287 μm2, as the product depth increased from 2 to 20 mm. Therefore, the sample volume, depth, and freezing temperature had significant effects on the microstructure and quality deterioration. LNSF at -100 °C effectively maintained the best quality and longest shelf life of frozen large yellow croaker.

Laser processing materials for photo-to-thermal applications

Photothermal conversion materials (PCMs) are crucial component in solar-thermal energy technologies. Although various PCMs with excellent sunlight harvesting have been developed for colorful solar-thermal applications, uniform and large-scale production of PCMs remains a challenge, and the PCMs prepared through the conventional methods are often non-site specific. Laser processing technology (LPT), as an efficient, convenient, green and sustainable technology, can directly create micro/nano structures and patterns at specific locations on materials surface, attracting widespread attention in photo-to-thermal applications. Here, we summarize the laser processing of preparing PCMs through laser sintering, laser modification, laser ablation in liquid, laser induced carbonization, and laser etching. We also introduce the working mechanism of LPT, and analyze the thermal conductivity, heat storage performance and hydrophilic/hydrophobic properties of the substrate after LPT treatment. Furthermore, the application of LPT in solar anti-icing/deicing, seawater desalination, heat exchange system, energy storage and transfer, and other related fields are introduced. Additionally, we provide a prospect for the development of LPT and offer directions for future research. We hope that this review can provide meaningful reference value for scholars in this field.

Expanding the cryoprotectant toolbox in biomedicine by multifunctional antifreeze peptides

The global cryopreservation market size rises exponentially due to increased demand for cell therapy-based products, assisted reproductive technology, and organ transplantation. Cryoprotectants (CPAs) are required to reduce ice-related damage, osmotic cell injury, and protein denaturation. Antioxidants are needed to hamper membrane lipid peroxidation under freezing stress, and antibiotics are added to the cryo-solutions to prevent contamination. The vitrification process for sized organs requires a high concentration of CPA, which is hardly achievable using conventional penetrating toxic CPAs like DMSO. Antifreeze peptides (AFpeps) are biocompatible CPAs leveraging inspiration from nature, such as freeze-tolerant and freeze-avoidant organisms, to circumvent logistic limitations in cryogenic conditions. This study aims to introduce the advances of AFpeps with cell-penetrating, antioxidant, and antimicrobial characteristics. We herein revisit the placement of AFpeps in the biobanking of cancer cells, immune cells, stem cells, blood cells, germ cells (sperms and oocytes), and probiotics. Implementing low-immunogenic AFpeps for allograft cryopreservation minimizes HLA mismatching risk after organ transplantation. Applying AFpeps to formulate bioinks with optimal rheology in extrusion-based 3D cryobiopriners expedites the bench-to-beside transition of bioprinted scaffolds. This study advocates that the fine-tuned synthetic or insect-derived AFpeps, forming round blunt-shape crystals, are biomedically broad-spectrum, and cell-permeable AFpeps from marine and plant sources, which result in sharp ice crystals, are appropriate for cryosurgery. Perspectives of the available room for developing peptide mimetics in favor of higher activity and stability and peptide-functionalized nanoparticles for enhanced delivery are delineated. Finally, antitumor immune activation by cryoimmunotherapy as an autologous in-vivo tumor lysate vaccine has been illustrated.

Strong self-association of chitosan microgels at interface mediated high stabilities in Pickering emulsion

The spontaneous self-organization of naturally-occurring polysaccharide particles into a thick and robust gel network at interface in Pickering emulsion is challenging. Inspired by the phenomenon that chitosan microgels (CSMs) with a certain size could self-associate into a solidified gel phase upon freezing, here we tentatively used CSMs to construct a highly-stable Pickering emulsion. CSMs can form a stable Langmuir's layer at the water/oil interface through the network deformation and re-arrangement of dangling chains, while the subsequent negative polymer coating can avoid the bridging resulting from the cross-association for CSMs on different emulsion droplets upon freezing. The experimental results indicated that the emulsion showed excellent features, including the wide pH range stability (3-12), long-term storage stability (> 3 months), thermal stability (121 °C, 30 min). Moreover, CSMs could self-associate into a reliable gel layer around the oil droplet in freezing, leading to the better freeze-thaw stability (1-3 cycles). The negative coating not only facilitates the formation of interfacial gel network around each emulsion droplet, but also produces huge steric hindrance and electrostatic repulsion to suppress the coalescence. This work provides a different way to modulate the interfacial structure, thus developing a more stable polysaccharide-based Pickering emulsion.

Investigating the cryoprotective mechanism of phosphorylated nano-chitin in shrimp (Litopenaeus vannamei) during frozen storage

This study aims to explore the cryoprotective effects of phosphorylated surface deacetylated chitin nanofibers (PS-ChNFs) on shrimp. Compared to the control- and those treated with surface deacetylated chitin nanofibers (S-ChNFs) or sodium tripolyphosphate (STPP), the PS-ChNFs-treated group showed lower thawing losses and cooking losses, alongside higher myofibrillar protein concentrations and Ca2+-ATPase activity in frozen shrimp. Additional, PS-ChNFs-treated significantly delayed protein aggregation and the deterioration of the secondary structure in shrimp during frozen storage (p < 0.05). Furthermore, microscopy analysis revealed PS-ChNFs effectively inhibited ice crystal growth and slowed the damage to muscle tissue structures. Molecular simulations suggested that the cryoprotective effect of PS-ChNFs were primarily achieved through the "water substitution" and "glassy state" hypotheses, wherein PS-ChNFs formed hydrogen bonds with water and reduced the number of water molecules around myosin. These findings indicate that PS-ChNFs hold significant potential as cryoprotectants for freeze-stored aquatic products.

Impact of magnetic field-assisted freezing on the physicochemical properties and starch structure of cooked rice: Effects of magnetic types, intensities, and cryostasis time

A magnetic field-assisted freezing system was developed to mitigate the degradation of taste quality in frozen cooked rice (FCR). The physicochemical properties and starch structure were analyzed under varying magnetic field types, intensities, and cryostasis time. The analysis of freezing characteristics indicated that treatments with 10 mT static magnetic fields (SMF) and 6 mT alternating magnetic fields (AMF) yielded optimal results, significantly reducing the duration of the maximum ice crystal generation zone by approximately 18 min. Compared to no magnetic field (NMF) treatment, a 16-day frozen storage experiment showed significant improvements in the texture characteristics of cooked rice treated with magnetic fields. However, the moisture content of rice treated with AMF closely resembled those of freshly cooked rice, with a slight increase in yellowness compared to SMF treatment. Throughout the storage period, the crystallinity for the AMF treatment exceeded that of the SMF treatment by 2.99 %. Furthermore, compared to SMF treatment, water molecules in FCR treated with AMF are more tightly bound. Given the superior sensory scores in the AMF treatment, it can be concluded that while SMF reduces color degradation, AMF is more effective in preserving moisture, and structural density. Hence, magnetic fields, especially AMF, emerge as a promising auxiliary technology for FCR, offering a theoretical basis for advancing cold chain logistics technology for cooked rice.

Dual-crosslinked reduced graphene oxide/polyimide aerogels possessing regulable superelasticity, fatigue resistance, and rigidity for thermal insulation and flame retardant protection in harsh conditions

Polyimide (PI) aerogels have various applications in aerospace, national defense, military industry, and rail transit equipment. This paper reports a series of ultra-lightweight, high elasticity, high strength, low thermal conductivity, and high flame retardant rGO/PI nanocomposite aerogels prepared by the ice templating method. The effects of freezing processes (unidirectional freezing and random freezing), chemical composition, and environmental temperature (-196-200 °C) on the morphology, mechanical, and thermal properties of the aerogels were systematically studied. The results indicated that unidirectional aerogels exhibit anisotropic mechanical properties and thermal performance. Compression in the horizontal direction showed high elasticity, high fatigue resistance, and superior thermal insulation. Meanwhile, in the vertical direction, it demonstrated high strength (PI-G-9 reaching 14 MPa). After 10,000 cycles of compression in the horizontal direction (at 50 % strain), the unidirectional PI-G-5 aerogel still retains 90.32 % height retention, and 78.5 % stress retention, and exhibited a low stable energy loss coefficient (22.11 %). It also possessed a low thermal conductivity (32.8 mW m-1 K-1) and demonstrated good thermal insulation performance by sustaining at 200 °C for 30 min. Interestingly, the elasticity of the aerogels was enhanced with decreasing temperatures, achieving a height recovery rate of up to 100 % when compressed in liquid nitrogen. More importantly, the rGO/PI aerogels could be utilized over a wide temperature range (-196-200 °C) and had a high limiting oxygen index (LOI) ranging from 43.3 to 48.1 %. Therefore, this work may provide a viable approach for designing thermal insulation and flame-retardant protective materials with excellent mechanical properties that are suitable for harsh environments.

Control of emulsion crystal growth in low-temperature environments

Currently, various types of emulsions can be applied to a wide range of systems. Emulsions are thermodynamically unstable systems, and their crystallization can be affected by a variety of factors. The nucleation and growth processes of emulsion crystal networks are determined on the basis of reported theoretical and experimental methods. The issues addressed include changes in the apparent crystal morphology of samples, changes in thermal properties with respect to temperature, changes in boundary conditions, and changes in the various applications of emulsions as feedstocks or in processing and storage methods. Changes in a variety of common emulsions during constant-temperature storage and unavoidable temperature fluctuations (e.g., multiple freeze-thaw cycles) are considered. Different methods for controlling the crystalline stability of these colloidal systems are also discussed. This review outlines the crystallization mechanism of emulsions during their food processing and storage.

Electric Field-Enhanced Ion Rejection Rate in Freeze Desalination

Freeze desalination is an appealing method for seawater desalination through freezing seawater. The percentage of ions in the liquid phase, which is termed ion rejection rate, is a critical factor affecting the performance of freeze desalination. Improving the ion rejection rate is an important topic for freeze desalination. In this work, we investigate the effects of electric fields on the ion rejection rate during the freezing of seawater through molecular dynamics simulations. It is found that the ion rejection rate increases with increasing electric field strength. The enhanced ion rejection rate is due to the reduction of the energy barrier at the ice-water interface caused by the electric field, which affects the orientation of water molecules and ion-water interactions. However, the electric field hinders the ice growth rate, which affects the productivity of freeze desalination. Nevertheless, the finding in this work offers a new idea to improve the ion rejection rate. Practically, a trade-off needs to be found to optimize the overall performance of freeze desalination.

Research Progress on the Effect and Mechanism of Superchilling Preservation Technology on Meat Quality Control

During storage and transportation, meat is susceptible to the effects of microorganisms, endogenous enzymes, and oxygen, leading to issues such as moisture loss, spoilage, and deterioration. Superchilling, as a preservation method that combines the benefits of refrigeration and freezing, can effectively slow the growth and reproduction of microorganisms, control protein and lipid oxidation, reduce water loss, and maintain the quality and sensory properties of meat. This paper reviews the current application status of superchilling technology in meat preservation, focusing on the mechanisms of ice crystal formation, water retention, tenderness preservation, protein and fat oxidation control, and microbial growth inhibition under superchilling conditions. Additionally, it summarizes the research progress on the combined application of superchilling with emerging technologies such as electric fields, magnetic fields, and electron beams in meat preservation and explores its potential and future prospects for improving meat quality. The aim is to provide scientific evidence and technical support for the application of superchilling technology in enhancing meat quality.

Time-Responsive Visualization of Cryogenic Detection Based on the Dynamic Optical Signals of CaZnOS

Cryogenic detection technology is essential to ensure safety and effectiveness in fields such as medical refrigeration, cold chain transport, and cryogenic bioengineering. In this paper, a time-responsive visual cryogenic detection strategy is developed based on the storage properties of CaZnOS: Pb2+, Pr3+ phosphors with shallow traps. Since the carrier release rate from the trap center receives the influence of ambient temperature and storage time, the storage time of the temperature-sensitive product can be determined by the different optical signals of CaZnOS: Pb2+, Pr3+ phosphors obtained under 980 nm laser irradiation. In addition, CaZnOS: Pb2+, Pr3+ phosphors with multimode luminescence enable time-responsive visual detection of ambient temperature under extreme conditions. This work not only demonstrates the potential of CaZnOS: Pb2+, Pr3+ phosphors for visual detection of temperature and time but also paves the way for the development of various applications relying on cryogenic monitoring.

Hydrogen-Bond-Repairing Solar Evaporator with Reconstructed Large-Width Channels for Durable Solarizing Seawater

Conventional solarizing seawater suffers from inefficiency and space constraints. Interfacial solar vapor generation (ISVG) presents an energy-efficient alternative, yet the scalability, adaptability, and durability of a solar evaporator for practical use are remaining concerns. Herein, a hydrogen-bond-repairing solar evaporator featuring reconstructed large-width channels is proposed for ongoing solarization of seawater in ISVG. The polyacrylamide/trehalose/graphene hydrogel (PTGH) exhibits excellent mechanical properties and large-width salt discharge channels. PTGH achieves a notable water evaporation rate of 2.82 kg m-2 h-1 under 1 sun and remains effective even in low-temperature environments. The large-area PTGH is able to continuously operate for solarizing seawater under different conditions, until raw brine is highly concentrated, and eventually solid salt is separated from water. Compared to conventional solarizing seawater, PTGH can save 66.67%-75% of time or land to obtain the same amount of solid salt.

Higher molecular weight pectin inhibits ice crystal growth and its effect on the microstructural and physical properties of pectin cryogels

Understanding the formation of ice crystals is essential for tailoring the microstructure and physical properties of cryogels. This study investigated the effects and mechanisms of pectin molecular weight (Mw) on impacting ice crystal formation. Pectin fractions various Mw (10.13-212.20 kDa) were prepared by hydrothermal method. The solution of high Mw pectin fractions exhibited higher contact angle, lower water freedom, and stronger adsorption of water molecules. The splat experiment and molecular dynamic (MD) results confirmed that higher Mw pectin have stronger ice crystal growth inhibition activity than lower Mw pectin. Furthermore, the pore size distribution of the cryogel increased from 98-203 μm to 105-267 μm as the molecular weight decreased from 212.2 kDa to 121.0 kDa. Additionally, in the higher Mw pectin cryogel, stronger mechanical strength was observed. These findings suggested that changing the molecular weight of pectin has the potential to regulate the ice crystal growth, microstructure and physical properties of frozen products.

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.

Antifreeze Polysaccharides from Wheat Bran: The Structural Characterization and Antifreeze Mechanism

Exploring a novel natural cryoprotectant and understanding its antifreeze mechanism allows the rational design of future sustainable antifreeze analogues. In this study, various antifreeze polysaccharides were isolated from wheat bran, and the antifreeze activity was comparatively studied in relation to the molecular structure. The antifreeze mechanism was further revealed based on the interactions of polysaccharides and water molecules through dynamic simulation analysis. The antifreeze polysaccharides showed distinct ice recrystallization inhibition activity, and structural analysis suggested that the polysaccharides were arabinoxylan, featuring a xylan backbone with a majority of Araf and minor fractions of Manp, Galp, and Glcp involved in the side chain. The antifreeze arabinoxylan, characterized by lower molecular weight, less branching, and more flexible conformation, could weaken the hydrogen bonding of the surrounding water molecules more evidently, thus retarding the transformation of water molecules into the ordered ice structure.

Freezing-mediated formation of supraproteins using depletion forces

Hypothesis Long-acting formulations such as microparticles, injectable depots and implantable devices can realize spatiotemporally controlled delivery of protein drugs to extend their therapeutic in vivo half-lives. To efficiently encapsulate the protein drugs into such drug delivery systems, (sub)micron-sized protein particles are needed. The formation of micronized supraproteins can be induced through the synergistic combination of attractive depletion forces and freezing. The size of the supraproteins can be fine-tuned from submicron to several microns by adjusting the ice crystallization rate through the freeze-quench depth, which is set by the target temperature. Methods Supraprotein micron structures were prepared from protein solutions under various conditions in the presence and absence of nonadsorbing polyethylene glycol. Scanning electron microscopy and dynamic light scattering were employed to determine the sizes of the supraproteins and real-time total internal reflection fluorescent microscopy was used to follow the supraprotein formation during freezing. The protein secondary structure was measured before and after micronization by circular dichroism. A phase diagram of a protein-polyethylene glycol mixture was theoretically predicted to investigate whether the depletion interaction can elucidate the phase behavior. Findings Micronized protein supraparticles could be prepared in a controlled manner by rapid freeze-drying of aqueous mixtures of bovine serum albumin, horseradish peroxidase and lysozyme mixed with polyethylene glycol. Upon freezing, the temperature quench initiates a phase separation process which is reminiscent of spinodal decomposition. This demixing is subsequently arrested during droplet phase separation to form protein-rich microstructures. The final size of the generated protein microparticles is determined by a competition between phase separation and cooling rate, which can be controlled by target temperature. The experimental phase diagram of the aqueous protein-polyethylene glycol dispersion aligns with predictions from depletion theory for charged colloids and nonadsorbing polymers.

Double-layer microcapsules based on shellac for enhancing probiotic survival during freeze drying, storage, and simulated gastrointestinal digestion

Probiotics are susceptible to diverse conditions during processing, storage, and digestion. Here, shellac (SC), sodium alginate (SA), coconut oil (CO), soybean oil (SO), and trehalose (AL) were used to prepare microcapsules aiming to improve the survival of Lactiplantibacillus plantarum KLDS1.0318 during freeze-drying, storage process, and gastrointestinal digestion. The results showed that for SA/AL/SC/CO and SA/AL/SC/SO, the survival loss decreased by 51.2 % and 51.0 % after a freeze-drying process compared with microcapsules embedded by SA; the viable bacteria count loss decreased by 4.36 and 4.24 log CFU/mL compared with free cell (CON) during storage for 28 d under 33%RH at 25 °C, respectively; while for simulating digestion in vitro, the survival loss decreased by 3.05 and 2.70 log CFU/mL, 0.63 and 0.55 log CFU/mL after digestion at simulated gastric fluid for 120 min and small intestine fluid for 180 min, respectively (P < 0.05). After microcapsules were added to fermented dairy stored at 4 °C for 21 d, the viable bacteria count of SA/AL/SC/CO and SA/AL/SC/SO significantly increased by 2.10 and 1.70 log CFU/mL compared with CON, respectively (P < 0.05). In conclusion, the current study indicated that shellac-based probiotic microcapsules have superior potential to protect and deliver probiotics in food systems.

Tracking protein aggregation behaviour and emulsifying properties induced by structural alterations in common carp (Cyprinus carpio) myofibrillar protein during long-term frozen storage

The effect of ultrasound-assisted immersion freezing (UIF), air freezing (AF), and immersion freezing (IF) on the protein structure, aggregation, and emulsifying properties of common carp (Cyprinus carpio) myofibrillar protein during frozen storage were evaluated in the present study. The result showed that, compared with AF and IF samples, UIF sample had higher reactive/total sulfhydryl, protein solubility, and lower protein turbidity (P < 0.05), indicating that UIF was beneficial to inhibit protein oxidation and aggregation induced by frozen storage. UIF inhibited the alteration of secondary structure and tertiary structure during frozen storage. Meanwhile, UIF sample had higher emulsifying activity index, and smaller emulsion droplet diameter than AF and IF samples (P < 0.05), suggesting that UIF was beneficial for maintaining the emulsifying properties of protein during storage. In general, UIF is a potential and effective method to suppress the decrease in protein emulsifying properties during long-term frozen storage.

Study on the Quality Variation and Internal Mechanisms of Frozen Oatmeal Cooked Noodles during Freeze-Thaw Cycles

Frozen staple food, attributed to its favorable taste and convenience, has a promising development potential in the future. Frequent freezing and thawing, however, will affect its quality. This study simulated several freeze-thaw cycles (FTC) that may occur during the cold chain process of frozen oatmeal cooked noodles (FOCN) production to consumption. The quality changes and their mechanisms were elucidated using methods such as differential scanning calorimetry (DSC), low-field nuclear magnetic resonance (LF-NMR), Fourier-transform infrared spectroscopy (FTIR), confocal laser scanning microscopy (CLSM), texture analysis, and sensory evaluation. The freezable water content of the FOCN decreased because of the FTC treatment, and the relative content of total water in FOCN also decreased accordingly. The increase in β-Turn after FTC induced disorder in the secondary structure of proteins, causing the protein microstructure to become loose and discontinuous, which in turn reduced the water-holding capacity of FOCN. Additionally, FTC reduced the chewiness and sensory score of FOCN. This research will contribute a theoretical foundation for optimizing the cold chain process.

Mechanism of low-voltage electrostatic fields on the water-holding capacity in frozen beef steak: Insights from myofilament lattice arrays

This study investigated the impact of low-voltage electrostatic field-assisted freezing on the water-holding capacity of beef steaks. The enhances mechanism of water-holding capacity by electrostatic field was elucidated through the detection of dynamic changes in the myofilament lattice and the construction of an in vitro myosin filaments model. The findings demonstrated that the disorder of the myofilament array, resulted from the aggregation of myosin filaments during freezing, is a crucial factor responsible for the water loss. The intervention of the electrostatic field can effectively reduce the myofibril density by 18.7%, while maintaining a regular lattice array by modulating electrostatic and hydrophobic interactions between myofibrils. Moreover, the electrostatic field significantly inhibited the migration of immobilized water to free water, thus resulting in an increase in the water-holding capacity of myofibrils by 36%. This work provides insights into the underlying mechanisms of water loss in frozen steaks and its regulation.

Non-destructive prediction of colour and water-related properties of frozen/thawed beef meat by Raman spectroscopy coupled multivariate calibration

Freeze-thaw accelerated the colour deterioration of beef with the increase of colour b* and the decrease of colour a* values (P < 0.05). The maximum exudate loss reached 22 % after the seventh freeze-thaw. A strong correlation between the transversal relaxation time T₂₁ and thawing loss may mean that T₂₁ water contributed to the exudate loss during freeze-thaw. Afterwards, competitive adaptive reweighted sampling-partial least square (CARS-PLS) has the best prediction in thawing loss of frozen/thawed beef with correlation coefficients of prediction (R_p) of 0.971, and root mean square error of prediction (RMSEP) of 1.436. Besides, Uninformative variable elimination-partial least squares (UVE-PLS) showed good prediction effects on colour values (R_p = 0.932 - 0.994) and water content (R_p = 0.928, RMSEP = 0.582) of frozen/thawed beef. Therefore, this work demonstrated that Raman spectroscopy coupled with multivariate calibration has a good ability for non-destructive prediction in colour and water-related properties of frozen/thawed beef.

Study of Water Freezing in Low-Fat Milky Ice Cream with Oat β-Glucan and Its Influence on Quality Indicators

The work is devoted to the study of the functional and technological properties of oat β-glucan in low-fat milky ice cream (2% fat) in comparison with the stabilization system Cremodan^® SI 320. β-glucan (0.5%) has a greater effect on the cryoscopic temperature of ice cream mixes than Cremodan^® SI 320 in the same amount (decrease by 0.166 °C vs. 0.078 °C), which inhibits the freezing process of free water in ice cream during technological processing in the temperature range from -5 to -10 °C. Microscopy of ice cream samples after freezing and hardening shows the ability of β-glucan to form a greater number of energy bonds due to specific interaction with milk proteins. Analysis of the microstructure of ice cream samples during 28 d of storage confirms the ability of oat β-glucan to suppress the growth of ice crystals more effectively than Cremodan^® SI 320. Oat β-glucan gives ice cream a rich creamy taste, increases overrun and resistance to melting, which brings this type of frozen dessert closer to a full-fat analogue (10% fat).

Research progress on quality deterioration mechanism and control technology of frozen muscle foods

Freezing can prolong the shelf life of muscle foods and is widely used in their preservation. However, inevitable quality deterioration can occur during freezing, frozen storage, and thawing. This review explores the eating quality deterioration characteristics (color, water holding capacity, tenderness, and flavor) and mechanisms (irregular ice crystals, oxidation, and hydrolysis of lipids and proteins) of frozen muscle foods. It also summarizes and classifies the novel physical-field-assisted-freezing technologies (high-pressure, ultrasound, and electromagnetic) and bioactive antifreeze (ice nucleation proteins, antifreeze proteins, natural deep eutectic solvents, carbohydrate, polyphenol, phosphate, and protein hydrolysates), regulating the dynamic process from water to ice. Moreover, some novel thermal and nonthermal thawing technologies to resolve the loss of water and nutrients caused by traditional thawing methods were also reviewed. We concluded that the physical damage caused by ice crystals was the primary reason for the deterioration in eating quality, and these novel techniques promoted the eating quality of frozen muscle foods under proper conditions, including appropriate parameters (power, time, and intermittent mode mentioned in ultrasound-assisted techniques; pressure involved in high-pressure-assisted techniques; and field strength involved in electromagnetic-assisted techniques) and the amounts of bioactive antifreeze. To obtain better quality frozen muscle foods, more efficient technologies and substances must be developed. The synergy of novel freezing/thawing technology may be more effective than individual applications. This knowledge may help improve the eating quality of frozen muscle foods.