Functional properties of proteins recovered from silver carp (Hypophthalmichthys molitrix) by isoelectric solubilization/precipitation

Isoelectric solubilization/precipitation at acidic and basic pH ranges was applied to whole gutted silver carp (Hypophthalmichthys molitrix) in order to recover muscle proteins. Thermal denaturation (T_onset, T_max, and ΔH), viscoelasticity (G′), and texture properties (shear stress) of proteins recovered from carp as affected by functional additives (beef plasma protein, potato starch, exogenous transglutaminase, polyphosphate, and titanium dioxide) were determined and compared to Alaska pollock surimi. Proteins recovered from carp showed typical endothermic transitions only when functional additives were used. Similar to endothermic transitions, viscoelasticity in carp proteins increased only when the additives were used. Typical endothermic peaks and viscoelasticity increase were recorded for Alaska pollock surimi. Carp protein-based gels with functional additives had lower (P < 0.05) shear stress than their surimi counterparts, but greater (P < 0.05) or similar (P > 0.05) when compared to surimi gels without functional additives. In addition, generally higher shear stress was measured for carp protein-based gels developed from basic pH treatments than the acidic counterparts. The present study indicates that proteins can be recovered from whole gutted carp using isoelectric solubilization/precipitation. However, if the recovered proteins are used for subsequent development of restructured food products, functional additives should be used.     

Effect of isoelectric solubilization/precipitation and titanium dioxide on whitening and texture of proteins recovered from dark chicken-meat processing by-products

Processing of chicken generates by-products containing muscle proteins attached to bones and skin that, if recovered, could be a functional ingredient in restructured food products. However, color of restructured products made of proteins recovered from chicken processing by-products is poor. The by-products contain bones, skin, fat, etc. that affect color of restructured products. Therefore, color properties need to be improved. The objectives of this study were to determine effects of isoelectric solubilization/precipitation (ISP) and TiO₂ on instrumental color and texture properties of heat-set gels made of proteins recovered from dark chicken-meat processing by-products as compared to gels made of chicken breast meat. Skin-on bone-in chicken drumsticks were used as a model dark chicken-meat processing by-products. TiO₂ at 0-1 g/100 g and canola oil at 10 g/100 g were added to the ISP-recovered proteins followed by cooking. Due to higher (P < 0.05) yellowness (b∗) and lower (P < 0.05) lightness (L∗), the whiteness of drumstick gels without TiO₂ was lower (P < 0.05) than breast gels. TiO₂ at 1 g/100 g with canola oil resulted in slightly better (P < 0.05) whiteness of drumstick gels than breast gels. TiO₂ did not deteriorate gel texture, which was generally comparable to breast gels. This research indicates that ISP allows recovery of proteins from skin-on bone-in dark chicken-meat processing by-products without removal of bones, skin, and fat prior to processing. Addition of TiO₂ to proteins recovered from these by-products allows development of heat-set gels with color and texture comparable to chicken breast gels. Although this study shows the potential for a novel, marketable food product, sensory tests are recommended.     

Physicochemical properties and gel-forming ability of surimi from three species of mackerel caught in Southern Thailand

Physicochemical and gelation properties of surimi prepared from three species of mackerel were investigated. The highest whiteness with the lowest redness index corresponding to the lowest myoglobin content especially its oxidised form, metmyoglobin, was found in short-bodied mackerel (Rastrelliger brachysoma) surimi (p < 0.05). Frigate mackerel (Auxis thazard) surimi contained the highest lipid content (p < 0.05). The pH of all surimi was in the range of 6.58–6.80. The highest sulfhydryl group and Ca²⁺-ATPase activity was found in natural actomyosin extracted from short-bodied mackerel surimi (p < 0.05). The highest TCA-soluble peptide content was found in frigate mackerel surimi gels (p < 0.05). Kamaboko gel of short-bodied mackerel surimi exhibited the highest breaking force with the lowest expressible drip (p < 0.05). Heating regime had no effect on deformability of gels from Indian mackerel (Rastrelliger kanagurta) and short-bodied mackerel but not for frigate mackerel. The highest metmyoglobin content with the lowest whiteness was found in frigate mackerel surimi gel (p < 0.05). Therefore, short-bodied mackerel was the best suited for the production of surimi with superior functional attributes including whiteness and gel-forming ability.     

Whey protein concentrate: Autolysis inhibition and effects on the gel properties of surimi prepared from tropical fish

Effects of whey protein concentrate (WPC) on autolysis inhibition and gel properties of surimi produced from bigeye snapper (Priacanthus tayenus), goatfish (Mulloidichthys vanicolensis), threadfin bream (Nemipterus bleekeri) and lizardfish (Saurida tumbil) were investigated. WPC (0–3%) showed inhibitory activity against autolysis in all surimi at both 60 and 65 °C in a concentration-dependent manner. Myosin heavy chain (MHC) of surimi was more retained in the presence of WPC. Breaking force and deformation of kamaboko gels of all surimi increased as added levels of WPC increased (P < 0.05). This was associated with lower levels of protein degradation, as evidenced by the decrease in trichloroacetic acid-soluble peptide content (P < 0.05). WPC at 3% (w/w) significantly decreased the whiteness of gels. However, water-holding capacity of kamaboko gels was improved with increasing concentration of WPC. The microstructure of surimi gels generally became denser with the addition of WPC.     

Impact of microbial transglutaminase on gelling properties of Indian mackerel fish protein isolates

Impacts of microbial transglutaminase (MTGase) (0–0.6 units/g sample) on gel properties of Indian mackerel unwashed mince, surimi and protein isolates with and without prewashing were studied. Generally, lower myoglobin and lipid contents were found in protein isolate with and without prewashing, compared to those of unwashed mince and surimi (P < 0.05). Protein isolate had the decreased Ca²⁺-ATPase and protein solubility, indicating protein denaturation. When MTGase was incorporated, breaking force and deformation of all gels markedly increased, especially as MTGase levels increased (P < 0.05). At the same MTGase level, gel from protein isolate with prewashing exhibited the highest breaking force and deformation (P < 0.05). The addition of MTGase could lower the expressible moisture content of most gels. No change in whiteness of gel was observed with the addition of MTGase (P > 0.05), but gel from protein isolate gels had decreased whiteness as MTGase at high level was added. The microstructure of protein isolate gels without prewashing showed a similar network to unwashed mince gels, whilst a similar network was observed between surimi gel and gel from protein isolate with prewashing. Nevertheless, a larger void was noticeable in gels from protein isolates. All gels incorporated with MTGase (0.6 units/g) showed a slightly denser network than those without MTGase. Thus, gel with improved properties could be obtained from protein isolate from Indian mackerel with added MTGase.     

Dynamic rheology and endothermic transitions of proteins recovered from chicken-meat processing by-products using isoelectric solubilization/precipitation and addition of TiO2

Chicken-meat processing generates large quantities of by-products (backs, necks, etc.). Dark chicken-meat processing by-products present the lowest value and greatest challenge. Therefore, recovery of functional proteins from this source for inclusion in food products resembling those from light chicken-meat presents the greatest value addition and opportunity. Novel isoelectric solubilization/precipitation (ISP) was applied to model, dark chicken-meat processing by-products (skin-on bone-in chicken drumsticks) to recover muscle proteins. Thermal denaturation (endothermic transitions), gelation (elasticity, G′), and fundamental texture properties (shear stress and strain at mechanical fracture) of the ISP-recovered proteins were determined with differential scanning calorimetry (DSC), dynamic rheometer, and torsion test, respectively; and compared to boneless skinless chicken breast. Endothermic transition of myosin was not detected only when TiO₂ was not added, while the ISP-recovered proteins with TiO₂ showed small myosin peak and large actin peak. However, the level of TiO₂ addition did not affect thermal transition/denaturation of the ISP-recovered proteins. The ISP-recovered proteins had a greater transition for actin compared to chicken breast, suggesting that ISP predisposes this protein to thermal denaturation. Similar to endothermic transitions, elasticity (G′) generally increased when TiO₂ was added to the ISP-recovered proteins. Gels made of chicken breast had the highest (P < 0.05) shear stress (i.e., gel strength), but gels made of the ISP-recovered chicken proteins had greater (P < 0.05) shear strain (i.e., gel cohesiveness). Addition of TiO₂ to the ISP-recovered proteins resulted in increased (P < 0.05) gel strength. Based on the present study, addition of TiO₂ is suggested for the development of restructured food products based on proteins recovered from dark chicken-meat processing by-products using ISP. Although the results of this study point towards a novel food product, further studies are recommended.     

Effects of konjac glucomannan on physicochemical properties of myofibrillar protein and surimi gels from grass carp (Ctenopharyngodon idella)

The cryoprotective effect of konjac glucomannan (KGM) on myofibrillar protein from grass carp (Ctenopharyngodon idella) during frozen storage at −18 °C and the influence of five levels of KGM (0%, 0.5%, 1%, 1.5%, and 2%) on texture properties, water-holding capacity, and whiteness of grass carp surimi gels were investigated. KGM as a novel cryoprotectant could significantly mitigate the decrease in salt extractable protein (SEP), Ca²⁺-ATPase activity, and total sulphydryl and active sulphydryl contents of myofibrillar protein during frozen storage. KGM at the level of 1% showed the same good cryoprotective effect as a conventional cryoprotectant (10% sucrose–sorbitol, 1:1, w/w). As the levels of KGM increased, breaking force and deformation of grass carp surimi gels increased significantly. Water-holding properties of the surimi gels are improved with the increasing addition of KGM, but the whiteness decreased and the colour became darker. The optimum addition level of KGM was suggested to be 1%.     

Enhancement of gel strength of bigeye snapper (Priacanthus tayenus) surimi using oxidised phenolic compounds

Effects of different oxidised phenolic compounds (ferulic acid, OFA; tannic acid, OTA; catechin, OCT and caffeic acid, OCF) at different levels (0–0.25% of protein content) on the properties of gels from bigeye snapper (Priacanthus tayenus) surimi were investigated. Breaking force and deformation of surimi gel varied with types and amounts of oxidised phenolic compounds. Gels added with 0.20% OFA, 0.05% OTA, 0.15% OCF and 0.05% OCT exhibited the marked increases in both breaking force and deformation, compared with the control (P < 0.05). Those increases were associated with lower expressible moisture content. No increases in both breaking force and deformation were observed when ferulic acid without oxygenation at alkaline pH was added, regardless of amount added (P > 0.05). No changes in the whiteness of gel were found with addition of OFA (P > 0.05), but the decreases in whiteness were noticeable as other oxidised phenolics were incorporated (P < 0.05). Different microstructures were obtained among gels with different oxidised phenolics. The physicochemical properties of natural actomyosin suggest that oxidised phenolics could induce conformational changes and the cross-linking through amino groups or the induction of disulphide bond formation. Therefore, the addition of oxidised phenolic compounds at the optimum level could increase the gel strength of surimi gel.     

Comparison of Atlantic menhaden gels from surimi processed by acid or alkaline solubilization

Heat-induced gelling abilities of surimis prepared by pH shifting (isoelectric precipitation following acid (AC) or alkaline (AL) solubilization) were compared to that of conventionally washed (CW) surimi. Greater endogenous transglutaminase activity (evidenced as enhanced strength of cooked gels subjected to 30–40 °C preincubation) was measured for CW and AL surimi than for AC surimi (all at pH 7). Upon addition of microbial transglutaminase (MTGase), increased crosslinking of myosin heavy chain and gel strengthening during 30–40 °C preincubation were apparent for all three types of surimi, most markedly in CW and AL surimi. Salt addition improved CW gels most, but seemed to adversely affect MTGase activity in AC and AL surimi. AC and AL surimi gels were of lower whiteness than were CW surimi gels.     

Biochemical and gelling properties of tilapia surimi and protein recovered using an acid-alkaline process

The biochemical and gel properties of tilapia surimi prepared by a conventional washing method and protein isolated using alkaline-acid-aided processes were studied. Solubility and recovery of protein was found to be highest by using a conventional method, followed by an alkaline- and acid-aided process, respectively. Decreases in myoglobin and lipid contents were found in alkaline- or acid-aided process when compared to the conventional process (p < 0.05). The highest breaking force and deformation of kamaboko and modori gels was found in the gels prepared by the conventional washing method. Higher expressible water and whiteness were found in modori gels when compared to kamaboko gels. TCA-soluble peptide contents of conventional surimi gels were lower than those of acid- and alkaline-recovered protein gels. Degradation of myofibrillar protein was observed in acid-isolated protein. Microstructure of kamaboko gels showed more compact network than in modori gels in both conventional surimi and protein recovered using the pH-shift process.     

Gel properties of croaker–mackerel surimi blend

Gel properties of croaker surimi blended with three types of mackerel surimi at different ratios were evaluated. The gel strength of the croaker–mackerel surimi blend was higher than that of the original mackerel surimi (p < 0.05). The presence of croaker surimi in the blend resulted in the increase in myosin heavy chain (MHC) band intensity. No differences in deformation of gels were observed in croaker surimi and croaker-short-bodied mackerel blend at all ratios (p > 0.05). The addition of short-bodied mackerel surimi into croaker surimi up to a ratio of 1:2 had no effect on whiteness and metmyoglobin content of the gel (p > 0.05). Marked decrease in expressible drip and TCA-soluble peptide of gel was noticeable in croaker–frigate mackerel surimi blend (p < 0.05). Therefore, the gel properties of croaker–mackerel surimi blend were governed by the type and content of mackerel surimi used.     

Effect of porcine plasma protein and setting on gel properties of surimi produced from fish caught in Thailand

Effects of porcine plasma protein (PPP) and high temperature setting on gel properties of surimi from bigeye snapper, bigeye croaker, threadfin bream and barracuda were investigated. PPP was effective in increasing breaking force and deformation of kamaboko gels set at 40°C for 30 min and heated at 90°C for 20 min. The optimum levels of PPP were 0.5, 0.5, 1.5 and 1.5 g/100 g and the optimum setting times were 2, 1.5, 1.5 and 2 h for bigeye snapper, bigeye croaker, threadfin bream and barracuda surimi, respectively. However, the addition of PPP significantly decreased whiteness (P<0.05). An increase in gel-forming ability of surimi with PPP coincided with a decrease in solubility in mixture of SDS, urea and β-mercaptoethanol, indicating the formation of nondisulfide covalent bond induced by both endogenous and plasma transglutaminase. The results supported that PPP improve the gelation of surimi in combination with setting.     

Effects of Hydrolysates from Silver Carp (Hypophthalmichthys molitrix) Scales on Rancidity Stability and Gel Properties of Fish Products

This study aimed to evaluate the effectiveness of hydrolysates, which were obtained from the scales of silver carp (Hypophthalmichthys molitrix) by papain, flavourzyme, and Alcalase 2.4 L, as natural antioxidants in silver carp mince and surimi gels during storage at 4 °C. The hydrolysates that possess greater in vitro antioxidant activities (DPPH radical-scavenging activity, Fe²⁺-chelating activity, and reducing power), including hydrolysates catalyzed by papain at 10 min (HP), flavourzyme at 5 min (HF), and Alcalase 2.4 L at 5 min (HA), were chosen as additives. Color, cooking loss, conjugated dienes (CDs), thiobarbituric acid reactive substances (TBARS), fatty acids, and sensory scores of mince were measured on days 0, 2, 4, 6, and 8 during 4 °C storage; additionally, whiteness, breaking force, deformation, gel strength, and sensory score of surimi gels were measured on days 1, 3, 5, 7, 9, and 11 during 4 °C storage. The results indicate that HA was conducive to lowering the cooking loss of mince and that HF significantly (P?<?0.05) reduced the CDs value of mince. For surimi gels, HF improved whiteness, deformation, and gel strength. Hence, HF could serve as a natural antioxidant during early oxidation and improve gel formation of silver carp products.     

Effect of iced storage of bigeye snapper (Priacanthus tayenus) on the chemical composition,properties and acceptability of Som-fug,a fermented Thai fish mince

The effect of iced storage of bigeye snapper (Priacanthus tayenus) on the chemical composition, properties and acceptability of Som-fug was investigated. During 15 days of iced storage, total volatile base (TVB), trimethylamine (TMA) and TCA-soluble peptide contents as well as thiobarbituric reactive substances (TBARS) of fish muscle increased continuously after 3 days of storage (p < 0.05). It was suggested that deterioration, protein degradation and lipid oxidation proceeded with increasing storage time. Som-fug prepared from surimi of bigeye snapper stored in ice for different times had similar pH, acidity and lactic acid bacteria count at the end of the fermentation (30 °C, 48 h). Generally, higher content of TCA-soluble peptides and higher TBARS were found in fermented Som-fug produced from bigeye snapper stored in ice for a longer time (p < 0.05). Hardness, adhesiveness, springiness, cohesiveness, and resilience of fermented Som-fug decreased with a concomitant increase in weight loss, released water and expressible water contents when fish kept for a longer time were used (p < 0.05). L^∗, a^∗, b^∗, whiteness and the likeness for appearance, colour, texture and flavour of Som-fug decreased when fish kept in ice for an extended time were used (p < 0.05). However, the taste likeness was not affected by iced storage time (p > 0.05). No differences in overall liking were noticeable when fish kept in ice for up to 12 days were used for Som-fug production (p > 0.05). Therefore, the quality of fish used as raw material should be an important factor in determining the characteristics of Som-fug.     

Flocculation-enhanced protein recovery from fish processing by-products by isoelectric solubilization/precipitation

Muscle proteins were recovered from rainbow trout processing by-products (fish meat leftover on bones, head, skin, and etc.) by isoelectric solubilization/precipitation. Muscle proteins precipitated at pH 5.5 are typically recovered by high-speed centrifugation at a laboratory scale, which appears to impede process scale-up. Our objective was to investigate the effect of flocculants on separation of precipitated proteins from process water (supernatant). Flocculants with different surface charge properties and molecular weights (M_w) were added to precipitated proteins. Protein separation was evaluated by determining optical density (OD) of the supernatant using Bradford dye-binding method. A high M_w anionic flocculent at 100 mg/L resulted in excellent protein separation following 10 min reaction. The OD of the supernatant was comparable to that of clear water, suggesting that even water-soluble fish muscle proteins were removed from the process water. Freeze-thaw cycles, commonly encountered in the fish processing industry, resulted in even more rapid flocculation reaction. This flocculent could be added to a bio-reactor that precipitates muscle proteins at pH 5.5 in a continuous isoelectric solubilization/precipitation system. However, effects of the flocculants on human and animal health should be determined and appropriate approvals obtained before the recovered muscle proteins can be used in human food products and/or animal feeds.     

Effects of washing with oxidising agents on the gel-forming ability and physicochemical properties of surimi produced from bigeye snapper (Priacanthus tayenus)

The effects of washing with hydrogen peroxide (H₂O₂) and sodium hypochlorite (NaOCl) solutions on the gel-forming ability and physicochemical properties of surimi produced from bigeye snapper (Priacanthus tayenus), stored in ice for up to 14 days, were investigated. Generally, pH and the trichloroacetic acid (TCA)-soluble peptide content of washed mince varied, depending on the type of oxidizing agent and storage time of the fish. With increasing time of storage, the pHs of water- and H₂O₂-washed mince were lower than that of NaOCl-washed mince (P < 0.05). However, no differences in the TCA-soluble peptide contents of the resulting mince washed with any media were observed (P > 0.05). Washing with 20 ppm NaOCl resulted in the highest increase in both the breaking force and the deformation of mince from fish stored in ice for all the times studied (P < 0.05). Natural actomyosin (NAM) extracted from NaOCl-washed mince had higher surface hydrophobicity and disulfide bond (SS) content than that of water-washed mince (P < 0.05). With no effect on Ca²⁺-, Mg²⁺-, or Mg²⁺–Ca²⁺-ATPase activities, NaOCl washing resulted in an increase in Mg²⁺–EGTA-ATPase activity of NAM (P < 0.05). The results suggested that washing mince with the appropriate type and concentration of oxidizing agent can improve the gelling ability of surimi, particularly from low quality fish.     

Effect of zinc sulphate on gelling properties of phosphorylated protein isolate from yellow stripe trevally

Impacts of zinc sulphate (ZnSO₄) (0–140 μmol/kg) on gel properties of yellow stripe trevally surimi added with sodium tripolyphosphate (STPP) (0.25% and 0.5%, w/w) and protein isolate phosphorylated with STPP at 0.25% and 0.5% (w/w) were studied. Gels from surimi added with 60 μmol ZnSO₄/kg in the absence and presence of 0.5% STPP had the increases in breaking force and deformation by 20.9% and 33.3%, and 11.6% and 18.6%, respectively, compared with the control surimi gel (without additives). Gel of protein isolate phosphorylated with 0.5% STPP containing 100 μmol ZnSO₄/kg had the increases in breaking force and deformation by 14.87% and 5.6%, respectively, compared with the gel from non-phosphorylated protein isolate at the same ZnSO₄ level, suggesting that the phosphorylated protein isolate was more crosslinked by Zn²⁺. The addition of ZnSO₄ at the suitable level lowered the expressible moisture content, but increased whiteness of surimi or protein isolate gels (P < 0.05). Non-covalent bonds, more likely salt bridge and ionic interactions, played a major role in cross-linking of proteins in both surimi and protein isolate added with ZnSO₄, regardless of phosphates incorporated. Microstructure study revealed that a gel having highly interconnected and denser network with smaller voids was formed when protein isolate phosphorylated with 0.5% STPP was added with ZnSO₄ at a level of 100 μmol/kg. Thus, gel with improved properties could be obtained from protein isolate from yellow stripe trevally phosphorylated with STPP in conjunction with addition of ZnSO₄ at an appropriate level.     

Texture and colour properties of proteins recovered from whole gutted silver carp (Hypophthalmichthys molitrix) using isoelectric solubilisation/precipitation

BACKGROUND: According to an FAO report, carp are the cheapest and by far the most commonly consumed fish in the world. Carp have minimal growth requirements, yet rapid growth rates. Although carp are generally considered unsuitable for human consumption in the USA, they have rapidly started populating major bodies of fresh water in the USA to the extent that commercial processing becomes of interest. However, typical mechanical means of meat recovery from carp are impractical owing to the bony nature of the carp carcass. Therefore the aim of the present study was to devise processing strategies to recover fish meat from carp that could be used in the development of human food products. RESULTS: Isoelectric solubilisation/precipitation at acidic and basic pH values was applied to whole gutted silver carp. Depending on the solubilisation pH, protein and fat recovery yields were approximately 420–660 and 800–950 g kg^?1 respectively. The process effectively removed impurities such as bones, scales, skin, fins, etc. from whole gutted carp. The proteins were concentrated to approximately 900 g kg^?1, while the fat was reduced by 970–990 g kg^?1. Functional additives (potato starch, beef plasma protein, transglutaminase and polyphosphate) improved (P < 0.05) the texture of carp protein‐based gels such that it was generally comparable to the texture of Alaska pollock surimi gels. Although titanium dioxide improved (P < 0.05) the whiteness of carp gels, it was lower (P < 0.05) than the whiteness of Alaska pollock surimi gels. CONCLUSION: Isoelectric solublisation/precipitation allows protein and lipid recovery from whole gutted carp. However, if the proteins are used as a gelling ingredient in fish food products, functional additives are recommended. Copyright © 2008 Society of Chemical Industry     

Effects of vegetable oils on gel properties of surimi gels

The objective of this study was to determine effects of vegetable oils (soybean, peanut, corn, and rap oils) on the textural, color, microstructural, sensory and rheological properties of surimi gels. As the vegetable oil concentration increased in surimi gels, breaking force of gels was decreased (P < 0.05), while expressible water and whiteness values were increased (P < 0.05). Surimi gels with peanut oil had higher breaking force values, comparing to those with other vegetable oils. Transmission electron microscope shows the similar-size droplets of peanut oil and corn oil in surimi gels. Sensory evaluation indicated that fish balls with 10 g/kg vegetable oils were accepted in term of taste, color and overall likeness by the panelists. Storage modulus (G′) and loss modulus (G″) decreased along with increasing vegetable oil concentration. Results demonstrated that vegetable oils could be used potentially to modify the qualities of surimi-based products, such as color and taste.     

Effects of superchilling and cryoprotectants on the quality of common carp (Cyprinus carpio) surimi: Microbial growth,oxidation, and physiochemical properties

The objective of the present study was to investigate the effect of superchilling with cryoprotectants (a mixture of sucrose and sorbitol) on microbial growth, lipid oxidation, and proteolytic degradation in common carp (Cyprinus carpio) surimi. With increasing storage time, the microbial count of surimi increased from 4.4 log₁₀ CFU/g (0 days) to 7.2, 6.2, 5.9, and 5.5 log₁₀ CFU/g (35 days; P < 0.05) in the samples superchilled at −1 °C, superchilled at −3 °C, superchilled at −3 °C with cryoprotectants, and frozen at −18 °C, respectively. The total volatile basic nitrogen and thiobarbituric acid-reactive substances exhibited an increasing trend (P < 0.05) similar to that obtained with the microbial growth, whereas the whiteness and lightness stability decreased (P < 0.05) with increasing storage time. The SDS-PAGE analysis revealed that the degree of protein degradation increased with increasing storage time. Compared with the sample frozen at −18 °C, superchilling at −1 °C and −3 °C resulted in a marked reduction in the microstructure deterioration of the myofibrillar protein gels, and the addition of cryoprotectants further reduced this deterioration. These results suggest that superchilling with cryoprotectants offers an effective approach for reducing microbial growth and lipid oxidation and limiting proteolytic degradation in common carp surimi.