Investigation of the antifreeze mechanism and effect on quality characteristics of largemouth bass (Micropterus salmoides) during F-T cycles by hAFP

Exploring the correlation of microbial community diversity and succession with protein degradation and impact on the production of volatile compounds during cold storage of grouper (Epinephelus coioides)

Microorganisms, proteins, and lipids play crucial and intricate roles in the aroma generation of aquatic products. To explore the impact of the interaction between microorganisms and proteins on the volatile compounds (VOCs) in grouper, this study employed whey protein isolate (WPI) to inhibit lipid oxidation and reduce mutual interference. Changes in bacterial profiles, metabolites, and VOCs were detected. Eighteen key VOCs associated with the overall flavor of grouper were identified, and the potential relationships among microorganisms, proteins, and VOCs were explored using a correlation network. Five microorganisms (Vibrio, Vagococcus, Pseudomonas, Psychrobacter, and Shewanella) closely related to characteristic flavor compounds were identified. Additionally, 30 differential metabolites related to proteins and six metabolic pathways were screened. Therefore, this study unveils the potential interaction between microorganisms and proteins in flavor formation and provides new insights into the relationships among microorganisms, proteins, and VOCs.

Screening and characterization of an antifreeze peptide from sea cucumber intestinal protein hydrolysates

Protein deterioration caused by ice crystals is an important factors affecting the frozen storage of fish. In this study, antifreeze peptides extracted from hydrolysates of sea cucumber intestinal protein with inhibition of protein denaturation were screened and characterized. The peptide Leu-Pro-Glu-Phe-Thr-Glu-Glu-Glu-Lys (LPEFTEEEK), derived from neutral protease hydrolysates of sea cucumber intestinal protein, was investigated for its potential to enhance the quality of salmon fillets during three freeze-thaw cycles. The results showed that the application of LPEFTEEEK effectively maintained the texture of fish fillets, as well as the oxidative and conformation stability of myofibrillar protein during the freezing process. Additionally, molecular dynamics simulations verified that LPEFTEEEK could bind to ice crystals and inhibit their recrystallization, thus preventing organisms from being damaged by freezing. This suggests that LPEFTEEEK holds significant promise as a novel cryoprotective agent for marine-derived antifreeze peptides.

Cryoprotective Activity of Different Characterized Fractions Isolated from Enzymatic Hydrolysates of Croceine Croaker (Pseudosciaena crocea)

In this study, ultrafiltration fractions (<3 k Da, LMH; >3 k Da, HMH) and solid-phase extraction fractions (hydrophilic hydrolysate, HIH; hydrophobic hydrolysate, HOH) from trypsin hydrolysate purified from croceine croaker (Pseudosciaena crocea) isolate were obtained to investigate the cryoprotective effects of the different fractions, achieved by means of maceration of turbot fish meat after three freeze-thaw cycles. Alterations in the texture, color, moisture loss, myofibrillar protein oxidation stability and conformation, and microstructure of the fish were analyzed after freezing and thawing. The results demonstrate that HIH maximized the retention of fish texture, reduced moisture loss, minimized the oxidation and aggregation of myofibrillar proteins, and stabilized the secondary and tertiary structures of myofibrillar proteins compared to the control group. In conclusion, the HIH component in the trypsin hydrolysates of croceine croaker significantly contributes to minimizing freeze damage in fish meat and acts as an anti-freezing agent with high industrial application potential.

Characterization and the mechanism underlying the cryoprotective activity of a peptide from large yellow croaker (Pseudosciaena crocea)

Ice crystal-induced protein denaturation is the main cause of the deterioration of fish during frozen storage and transportation. In this study, the ultra-performance liquid chromatography - quadrupole - time of flight (UPLC-Q-TOF) technique was used to identify and screen tryptic peptides Ile-Glu-Glu-Leu-Glu-Glu-Leu-Glu-Ala-Glu-Arg (IEELEEELEAER) from large yellow croaker (Pseudosciaena crocea). The results were used study their cryoprotective effects on turbot fish meat during freeze-thaw cycles at different concentrations, and to investigate their anti-freezing mechanism. The results showed that the I-2.0 group effectively inhibiting the degeneration and structure changes of myofibrillar proteins after three freeze-thaw cycles, and the Ca2+-ATPase activity (1.65 μmolPi/mg/h), increased by 55.86% compared with that of the control group. Additionally, peptide IEELEEELEAER could provide antifreeze protection by binding to the surface of ice crystals and inhibiting their transformation. This peptide acts as a natural cryoprotectant and might be used for the cryogenic storage and transportation of fish products.

Inhibition mechanism of membrane-separated silver carp hydrolysates on ice crystal growth obtained through experiments and molecular dynamics simulation

The membrane-separated silver carp hydrolysates (>10 k_D, 3-10 k_D and < 3 k_D) displayed abilities to mitigate oxidation and denaturation of myofibrillar protein and cryoprotective activities for frozen surimi. However, the mechanism of the membrane-separated fractions on ice crystal growth in the system is still unknown. Therefore, the cryoprotective activities (recrystallization inhibition, RI and thermal hysteresis activity, THA) of the fractions were investigated and the mechanism was explored by molecular dynamics (MD) simulation to predict the probable binding sites and model the possible interactions between the peptides and water/ice. The fractions < 3 k_D displayed remarkable RI activity, with significantly higher THA (0.60 ± 0.13 °C) and lower amount of ice nuclei (4.74 ± 0.53%) than that of fractions > 10 k_D and 3-10 k_D. The results of MD simulation certified that the main peptides in the fractions < 3 k_D interacted firmly with water molecules and inhibited growth of ice crystals with mechanism compatible with Kelvin effect. Hydrophilic and hydrophobic amino acid residues in the membrane-separated fractions offered synergistic effects on the inhibition of ice crystals.

The mechanisms and applications of cryoprotectants in aquatic products: An overview

Frozen storage technology has been widely used for the preservation of Aquatic products. However, ice crystals formation, lipid oxidation and protein denaturation still easily causes aquatic products deterioration. Cryoprotectants are a series of food additives that could efficiently prolong the shelf life and guarantee the acceptability of frozen aquatic products. This review comprehensively illustrated the mechanism of protein denaturation caused by the ice crystal formation and lipid oxidation. The cryoprotective mechanism of various kinds of antifreeze agents (saccharides, phosphates, antifreeze proteins and peptides) and these cryoprotective structure-activity relationship, application efficiency on the quality of aquatic products were also discussed. Moreover, the advantages and disadvantages of each cryoprotectant are also prospected. Compared with others, antifreeze peptides show higher commercial and application values. While, lots of scientific research works are still required to develop novel antifreeze agent as a versatile ingredient with commercial value, applicable in the aquatic products preservation industry.

Quinoa protein Pickering emulsion: A promising cryoprotectant to enhance the freeze-thaw stability of fish myofibril gels

In this work, the effects of different QPE addition on the freeze-thaw (F-T) stability of fish myofibrillar protein (MP) gels were revealed. During freezing process, QPE decreased the freezing point of MP gels and shortened the time to pass through the maximum-ice-crystal-formation zone. The occurrence of thermal hysteresis effect led to the formation of small ice crystals and alleviated the damage to MP gel network. The incorporation of 7.5% QPE also reduced the free water amount to 19.23% and improved the water holding capacity of MP gels. Furthermore, the incorporation of QPE decreased the carbonyl content of MP gels after F-T cycles and delayed the protein oxidation. Meanwhile, QPE addition maintained the stability of the tertiary structure of MP gels via stabilizing the microenvironment of tyrosine and tryptophan. Overall, QPE shows the potential as a new cryoprotectant to improve the F-T stability of MP gel products.

Precision cellular agriculture: The future role of recombinantly expressed protein as food

Cellular agriculture is a rapidly emerging field, within which cultured meat has attracted the majority of media attention in recent years. An equally promising area of cellular agriculture, and one that has produced far more actual food ingredients that have been incorporated into commercially available products, is the use of cellular hosts to produce soluble proteins, herein referred to as precision cellular agriculture (PCAg). In PCAg, specific animal- or plant-sourced proteins are expressed recombinantly in unicellular hosts-the majority of which are yeast-and harvested for food use. The numerous advantages of PCAg over traditional agriculture, including a smaller carbon footprint and more consistent products, have led to extensive research on its utility. This review is the first to survey proteins currently being expressed using PCAg for food purposes. A growing number of viable expression hosts and recent advances for increased protein yields and process optimization have led to its application for producing milk, egg, and muscle proteins; plant hemoglobin; sweet-tasting plant proteins; and ice-binding proteins. Current knowledge gaps present research opportunities for optimizing expression hosts, tailoring posttranslational modifications, and expanding the scope of proteins produced. Considerations for the expansion of PCAg and its implications on food regulation, society, ethics, and the environment are also discussed. Considering the current trajectory of PCAg, food proteins from any biological source can likely be expressed recombinantly and used as purified food ingredients to create novel and tailored food products.

Characterizations and the Mechanism Underlying Cryoprotective Activity of Peptides from Enzymatic Hydrolysates of Pseudosciaena crocea

Antifreeze peptides are a class of small molecule protein hydrolysates that protect frozen products from cold damage under freezing or subcooling conditions. In this study, three different Pseudosciaena crocea (P. crocea) peptides were from pepsin, trypsin, and neutral protease enzymatic hydrolysis. It aimed to elect the P. crocea peptides with better activity through molecular weight, antioxidant activity, and amino acid analysis, as well as to compare the cryoprotective effects with a commercial cryoprotectant. The results showed that the untreated fillets were prone to be oxidized, and the water-holding capacity after freeze-thaw cycle decreased. However, the treatment of the trypsin hydrolysate of P. crocea protein significantly promoted the water-holding capacity level and reduced the loss of Ca²⁺-ATP enzyme activity and the structural integrity damage of myofibrillar protein in surimi. Moreover, compared with 4% sucrose-added fillets, trypsin hydrolysate treatment enhanced the umami of frozen fillets and reduced the unnecessary sweetness. Therefore, the trypsin hydrolysate of P. crocea protein could be used as a natural cryoprotectant for aquatic products. Hence, this study provides technical support for its use as a food additive to improve the quality of aquatic products after thawing and provides a theoretical basis and experimental foundation for the in-depth research and application of antifreeze peptides.

Effect of antifreeze proteins on the freeze-thaw cycle of foods: fundamentals, mechanisms of action, current challenges and recommendations for future work

Freezing is widely used in food preservation, but if not carried out properly, ice crystals can multiply (nucleation) or grow (recrystallization) rapidly. This also affects thawing, causing structural damage and affecting overall quality. The objective of this review is to comprehensively study the cryoprotective effect of antifreeze proteins (AFPs), highlighting their role in the freeze-thaw process of food. The properties of AFPs are based on their thermal hysteresis capacity (THC), on the modification of crystal morphology and on the inhibition of ice recrystallization. The mechanism of action of AFPs is based on the adsorption-inhibition theory, but the specific role of hydrogen and hydrophobic bonds/residues and structural characteristics is also detailed. Because of the properties of AFPs, they have been successfully used to preserve the quality of a wide variety of refrigerated and frozen foods. Among the limitations of the use of AFPs, the high cost of production stands out, but currently there are solutions such as the use the production of recombinant proteins, cloning and chemical synthesis. Although in vitro, in vivo and human studies have shown that AFPs are non-toxic, their safety remains a matter of debate. Further studies are recommended to expand knowledge about AFPs, to reduce costs in their large-scale production, to understand their interaction with other food compounds and their possible effects on the consumer.

A review on recent advances in the applications of composite Fe3O4 magnetic nanoparticles in the food industry

Fe3O4 magnetic nanoparticles (MNPs) have attracted tremendous attention due to their superparamagnetic properties, large specific surface area, high biocompatibility, non-toxicity, large-scale production, and recyclability. More importantly, numerous hydroxyl groups (-OH) on the surface of Fe3O4 MNPs can provide coupling sites for various modifiers, forming versatile nanocomposites for applications in the energy, biomedicine, and environmental fields. With the development of science and technology, the potential of nanotechnology in the food industry has also gradually become prominent. However, the application of composite Fe3O4 MNPs in the food industry has not been systematically summarized. Herein, this article reviews composite Fe3O4 MNPs, including their properties, modifications, and physical functions, as well as their applications in the entire food industry from production to processing, storage, and detection. This review lays a solid foundation for promoting food innovation and improving food quality and safety.

Effects and mechanism of antifreeze peptides from silver carp scales on the freeze-thaw stability of frozen surimi

The objective of this work was to investigate the cryoprotective effects of antifreeze peptides obtained from silver carp scales (ScAFPs) on the freeze-thaw stability of surimi, and to explore the action mechanisms of ScAFPs on frozen surimi. The comprehensive analysis of ice crystal size, myofibril protein oxidation, water retention, surimi gel properties, and rheological properties of surimi after different freeze-thaw cycles were investigated. Results showed that frozen surimi treated with ScAFPs exhibited a higher Ca²⁺-ATPase activity, salt-soluble protein concentration and sulfhydryl group content, while lower surface hydrophobicity, carbonyl content and disulfide bond content. Moreover, the gel properties and water holding capacity of surimi and surimi gel were improved significantly by regulating the size of ice crystals during freeze-thaw process. These findings indicate that ScAFPs could serviced as a new food ingredient with anti-freezing function for frozen products.

A potential spoilage bacteria inactivation approach on frozen fish

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US&HVEF technology revealed an inactivation effect on S. putrefaciens.

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US&HVEF technology minimized the thawing damage to frozen fish.

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US&HVEF thawing achieved better quality maintenance of frozen aquatic products.

Frozen products are more susceptible to microbial spoilage during thawing. Therefore, the development of a thawing technology with effective bacteriostasis is still urgent in food science. In this study, red sea bream was used as the research object, S. putrefaciens was incubated on the surface of fish fillets, and ultrasound plus high voltage electric field (US&HVEF) was performed to investigate the antibacterial activity. On this basis, the effect of US&HVEF thawing on the quality characteristics of fillets was further studied. The results indicated that US&HVEF showed a better antibacterial performance toward S. putrefaciens, with the lethality of 96.73%. Furthermore, US&HVEF could minimize thawing loss, preserve fillets texture, stabilize the secondary and tertiary conformation of myofibrillar protein (MFP), and inhibit the MFP aggregation and oxidation. Accordingly, this study shows that food safety also involves spoilage bacteria prevention except for quality and proves that US&HVEF technology has great potential in food thawing.

Regulatory mechanisms governing collagen peptides and their 3D printing application for frozen surimi

Myofibrillar proteins (MPs) are important to the gel formation that occurs in frozen surimi. Importantly, their unique gel-forming ability indicates that surimi may be a promising material for use in 3D printing. The objective of the present study was to investigate the effects of collagen peptides on the cryoprotection of MPs during freeze-thaw (FT) cycles and the subsequent printability of surimi. The results showed that the collagen peptide had both protective and destructive actions during the tested FT cycles. The addition of 1.0% collagen peptide provided significant cryoprotection to the MPs. This addition effectively maintained the structural stability of MPs while also weakening FT effects on bound water and its mobility. We also assessed the rheological and 3D-printing characteristics of surimi with 1.0% collagen peptide. The rheological results indicated that the surimi with collagen peptides had better characteristics, including shear-thinning behavior, better recovery, and improved mechanical properties. Combined with the actual printing effect, materials with good shear-thinning behavior, high apparent viscosity, and high recovery might be more suitable for 3D printing. Moreover, the high G' contributed to good structural maintenance after printing. Collectively, these results indicated that collagen peptide may serve as a new, low-sugar cryoprotectant for use in surimi. Moreover, that its use would result in a healthier system that has increased stability, precision, and formability with applications in extrusion-based 3D printing. The results of this study provide theoretical reference for the development of new surimi materials with freezing stability and good 3D printing performance. PRACTICAL APPLICATION: This study confirmed the protective action of 1.0% collagen peptides for surimi and the contribution of it to well printing precision and structure maintenance for 3D printing, providing a firm foundation for the use of collagen peptide as a low-sugar cryoprotectant and developed a new type of surimi as a food material for 3D printing.

Antifreeze Proteins: Novel Applications and Navigation towards Their Clinical Application in Cryobanking

Antifreeze proteins (AFPs) or thermal hysteresis (TH) proteins are biomolecular gifts of nature to sustain life in extremely cold environments. This family of peptides, glycopeptides and proteins produced by diverse organisms including bacteria, yeast, insects and fish act by non-colligatively depressing the freezing temperature of the water below its melting point in a process termed thermal hysteresis which is then responsible for ice crystal equilibrium and inhibition of ice recrystallisation; the major cause of cell dehydration, membrane rupture and subsequent cryodamage. Scientists on the other hand have been exploring various substances as cryoprotectants. Some of the cryoprotectants in use include trehalose, dimethyl sulfoxide (DMSO), ethylene glycol (EG), sucrose, propylene glycol (PG) and glycerol but their extensive application is limited mostly by toxicity, thus fueling the quest for better cryoprotectants. Hence, extracting or synthesizing antifreeze protein and testing their cryoprotective activity has become a popular topic among researchers. Research concerning AFPs encompasses lots of effort ranging from understanding their sources and mechanism of action, extraction and purification/synthesis to structural elucidation with the aim of achieving better outcomes in cryopreservation. This review explores the potential clinical application of AFPs in the cryopreservation of different cells, tissues and organs. Here, we discuss novel approaches, identify research gaps and propose future research directions in the application of AFPs based on recent studies with the aim of achieving successful clinical and commercial use of AFPs in the future.

Novel synergistic freezing methods and technologies for enhanced food product quality: A critical review

Freezing has a long history as an effective food preservation method, but traditional freezing technologies have quality limitations, such as the potential for water loss and/or shrinkage and/or nutrient loss, etc. in the frozen products. Due to enhanced quality preservation and simpler thawing operation, synergistic technologies for freezing are emerging as the optimal methods for frozen food processing. This article comprehensively reviewed the recently developed synergistic technologies for freezing and pretreatment, for example, ultrasonication, cell alive system freezing, glass transition temperature regulation, high pressure freezing, pulsed electric field pretreatment, osmotic pretreatment, and antifreeze protein pretreatment, etc. The mechanisms and applications of these techniques are outlined briefly here. Though the application of new treatments in freezing is relatively mature, reducing the energy consumption in the application of these new technologies is a key issue for future research. It is also necessary to consider scale-up issues involved in large-scale applications as much of the research effort so far is limited to laboratory or pilot scale. For future development, intelligent freezing should be given more attention. Freezing should automatically identify and respond to different freezing conditions according to the nature of different materials to achieve more efficient freezing. PRACTICAL APPLICATION: This paper provides a reference for subsequent production and research, and analyzes the advantages and disadvantages of different novel synergistic technologies, which points out the direction for subsequent industry development and research. At the same time, it provides new ideas for the freezing industry.

Effects of Ultrasound-Assisted Vacuum Impregnation Antifreeze Protein on the Water-Holding Capacity and Texture Properties of the Yesso Scallop Adductor Muscle during Freeze-Thaw Cycles

The effect of antifreeze protein (AFP) on the water-holding capacity (WHC) and texture properties of the Patinopecten yessoensis adductor muscles during freeze–thaw cycles (FTCs) were evaluated based on three impregnation methods: general impregnation (GI), vacuum impregnation (VI), and ultrasound-assisted VI (US-VI). The WHC, texture properties, and tissue microstructure were all evaluated. Results showed that the WHC and texture properties of adductor muscle were significantly improved in the VI and US-VI groups during FTCs (p < 0.05). The WHC of the adductor muscle in the US-VI group was maximally enhanced in terms of yield (6.63%), centrifugal loss, cooking loss, and T₂₂. The US-VI group of the adductor muscle had the optimal chewiness and springiness compared to others, and the shear force and hardness were most effectively enhanced by VI. The growth and recrystallization of ice crystals in the frozen adductor muscle were significantly inhibited by VI and US-VI. The average cross-sectional area and roundness of ice crystals in the US-VI group were decreased by 61.89% and increased by 22.22% compared with those of the control, respectively. The partial least squares regression (PLSR) model further confirmed that the WHC and texture properties of the adductor muscle were correlated appreciably with the degree of modification of ice crystal morphology through the AFP.

Comparison of Physicochemical Changes and Water Migration of Acinetobacter johnsonii, Shewanella putrefaciens, and Cocultures From Spoiled Bigeye Tuna (Thunnus obesus) During Cold Storage

This study investigates the physicochemical changes and water migration of Acinetobacter johnsonii (A), Shewanella putrefaciens (S), and cocultured A. johnsonii and S. putrefaciens (AS) inoculated into bigeye tuna during cold storage. The physicochemical indexes [fluorescence ratio (FR), total volatile base nitrogen (TVB-N), thiobarbituric acid (TBA), trimethylamine (TMA), peroxide value (POV), and pH] of bigeye tuna increased cold storage. A significant decrease in trapped water was found in the AS samples, and direct monitoring of the water dynamics was provided by low-field nuclear magnetic resonance. Samples inoculated with A. johnsonii and S. putrefaciens also induced the degradation of myofibrillar proteins and weakness of some Z-lines and M-lines. Higher values of physicochemical indexes and water dynamics were shown in the coculture of S. putrefaciens and A. johnsonii than in the other groups. Therefore, this paper reveals that the coculture of A. johnsonii and S. putrefaciens resulted in a bigeye tuna that was more easily spoiled when compared to the single culture. This study provides insight into the spoilage potential of A. johnsonii and S. putrefaciens during cold storage, which further assists in the application of appropriate technologies to keep the freshness of aquatic foods.

Freezing of meat and aquatic food: Underlying mechanisms and implications on protein oxidation

Over the recent decades,protein oxidation in muscle foods has gained increasing research interests as it is known that protein oxidation can affect eating quality and nutritional value of meat and aquatic products. Protein oxidation occurs during freezing/thawing and frozen storage of muscle foods, leading to irreversible physicochemical changes and impaired quality traits. Controlling oxidative damage to muscle foods during such technological processes requires a deeper understanding of the mechanisms of freezing-induced protein oxidation. This review focus on key physicochemical factors in freezing/thawing and frozen storage of muscle foods, such as formation of ice crystals, freeze concentrating and macromolecular crowding effect, instability of proteins at the ice-water interface, freezer burn, lipid oxidation, and so on. Possible relationships between these physicochemical factors and protein oxidation are thoroughly discussed. In addition, the occurrence of protein oxidation, the impact on eating quality and nutrition, and controlling methods are also briefly reviewed. This review will shed light on the complicated mechanism of protein oxidation in frozen muscle foods.

Impact of ice structuring protein on myofibrillar protein aggregation behaviour and structural property of quick-frozen patty during frozen storage

The goal of this study was to explore the cryoprotective effect of ice structuring protein (ISP) on the aggregation behaviour and structural changes of myofibrillar protein (MP) from quick-frozen pork patties during frozen storage. Frozen storage causes the formation of large protein aggregates and weakens MP structures. After adding ISP into patties, MP had a more stable aggregation system, which was manifested by a uniform particle size distribution and significantly higher absolute zeta potential (11.71 mV) than the control (9.56 mV) (P < 0.05). Atomic force microscopy results showed that the surface roughness of MP aggregation decreased by 9.78% with ISP after freezing for 180 d. Additionally, compared to patties without ISP, the MP carbonyl content from the ISP-treated patty decreased by 32%, and the free amino content increased by 14.99% during frozen storage. Results from circular dichroism spectroscopy and fluorescence spectroscopy showed that MP secondary and tertiary structure stability in patties improved with ISP. Overall, ISP has the potential to improve MP aggregation and structural stability during frozen storage.

Inhibiting effect of ice structuring protein on the decreased gelling properties of protein from quick-frozen pork patty subjected to frozen storage

The effect of ice structuring protein (ISP) on the gelling properties of myofibrillar protein from quick-frozen pork patty during frozen storage was investigated by determining and comparing protein solubility, turbidity and gel properties. Protein solubility was increased by 10.23% and turbidity was decreased after ISP treated. The gel whiteness and strength of myofibrillar protein from patty with ISP were 8.38% and 13.70% higher than that of the control after frozen for 180 days. And the addition of ISP could weaken the influence of frozen storage on water mobility and reduce the water loss. Furthermore, ISP retrained the decrease in the maximum elastic (G') value and loss factor (tan δ) value of samples. Through observing by scanning electron microscope (SEM), ISP retarded the destruction of gel microstructure and maintained the relatively complete tissue of gel. These findings confirmed the importance of ISP in myofibrillar protein gel quality assurance of pork patty during frozen storage.

Insights into the similarities and differences of whiteleg shrimp pre-soaked with sodium tripolyphosphate and sodium trimetaphosphate during frozen storage

In this study, similarities and differences of sodium tripolyphosphate (STPP) and sodium trimetaphosphate (STMP) pre-soaking on the stability of muscle proteins in shrimp were investigated during 12 weeks of frozen storage (-30 °C). The physicochemical analysis indicated significant improvements in the WHC, springiness, chewiness, and thermal stability of STPP and STMP pre-soaked samples when compared to the control. Interestingly, STMP pre-soaking showed better cryoprotective effects than the STPP treatment when the storage period reached the end of the 12 weeks. Furthermore, the label-free based proteomics results indicated that 62 upregulated differentially abundant proteins (DAPs) were detected in STMP when compared to STPP. These identified DAPs specifically included 40S ribosomal proteins, actin-related proteins, heat shock proteins, myosin heavy chain, and tubulin beta chain. Additionally, the gene ontology (GO) and eukaryotic clusters of orthologous group (KOG) analyses verified that the incorporation of STMP molecules enhanced the resistance of cytoskeleton proteins to cold-temperature stress.

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

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.