Surimi Protein Research Articles

Interaction between liposome and myofibrillar protein in surimi: Effect on gel structure and digestive characteristics

This study investigated the effects of the interaction between liposomes and myofibrillar protein (MP) on tilapia surimi. The strong interaction between liposomes and MP was primarily mediated through hydrogen bonding and hydrophobic interaction. Liposomes caused the unfolding of MP structure, resulting in the decrease of α-helix content and transformation of spatial structure. Notably, the appropriate ratio of liposomes improved the gel properties of tilapia surimi. The water distribution, microstructure, and texture characteristics further confirmed that liposomes strengthened the structure of surimi gel through non-covalent bonds. However, excessive liposomes (1.0 %) weakened gel characteristics and texture. Moreover, the proper ratio of liposomes enhanced the stability of surimi gels during digestion, reducing protein digestibility from 66.0 % to 54.8 %. Curcumin-loaded liposomes in gel matrix notably delayed digestion and improved bioavailability. This delay in digestion was attributed to the ability of liposomes to decrease the interaction between MP and digestive enzymes. This study provides new insight into the application of liposomes in protein-rich food matrixes.

Hyperoside improves the textural and rheological properties of threadfin bream surimi gel

SummaryTextural, rheological, structural and sensorial properties of threadfin bream surimi as influenced by the addition of hyperoside (HyS) at various levels (0%–4%; w/w) were investigated. Surimi gel added with 1% and 2% HyS (HyS1 and HyS2, respectively) had the highest breaking force and deformation (P < 0.05). HyS2 showed the maximum water‐holding capacity, followed by HyS1 (P < 0.05). Whiteness of gel was decreased when the concentration of HyS was higher than 1%. Hardness, springiness, gumminess and chewiness increased with the addition of 1%–2% HyS (P < 0.05). HyS enhanced the connections between surimi proteins as supported by the appearance of some polymerised proteins. No major changes in the secondary structure of myofibrillar proteins in gel were noticed as determined by FTIR. Microstructure also revealed the formation of higher connectivity in the gel network with the addition of 1%–2% HyS. Likeness score for taste and flavour slightly decreased (P < 0.05), but the overall likeness score for HyS1 was still higher than the acceptable limit (score of 5). Therefore, the addition of HyS improved the gelling properties of threadfin surimi gel, which could be claimed as a functional food due to the several health benefits of HyS. Nevertheless, future studies should be conducted to reduce the bitterness associated with HyS incorporation.

Study on the structure and preservation mechanism of 3D-Printed surimi with Ca2+ and Xylo-oligosaccharides

The viscosity and plasticity of surimi is remarkable, which is a suitable 3D printing material. But low printing accuracy limit its wide application. Adding xylo-oligosaccharide (XOS) can enhance printing accuracy of surimi printing ink and improve the self-supporting ability and anti-deformation ability of the printed object. At the same time, XOS can impart antioxidant properties to 3D printed surimi. Additionally, adding 20 mM kg−1 of Ca2+ to the surimi can significantly improve the printing accuracy. With the addition of Ca2+, the gel strength and texture of surimi are enhanced, as well as the surimi protein became denser. Moreover, the Ca2+ in the “ink” can activate the activity of digestive enzymes which increase the contact of enzymes and surimi. The process of enzymatic hydrolysis is promoted, which improving the release rate and antioxidant properties of XOS. Functional surimi with Ca2+ can be used to deliver functional components and enhance the printing effects.

Investigation of cryoprotectants-treated surimi protein deterioration during chilled and frozen storage: Functional properties and kinetic modeling.

The relative cryoprotective effects of flaxseed protein hydrolysate and pectin in comparison with conventional cryoprotectant (sucrose + sorbitol + sodium tripolyphosphates) on stabilization of proteins in surimi of Capoor (Cyprinus carpio) were investigated during freezing (-20°C for 4 months) and chilling storage (4°C for 10 days). Although pectin caused to improve water-holding capacity (27.8%; 4°C and 21.5%; -20°C) on account of highly more inhibitory impact on the ice crystals growth, the protein denaturation may have occurred. It can be related to higher reduction in the amount of salt extractable protein (%) and the immeasurable value of thiol group in surimi formulation containing pectin compared with other cryoprotectants. The results of modeling surimi samples showed that salt extractable protein and sulfhydryl content were in good agreement with the first-order reaction model at -20°C and second-order kinetic model at 4°C. In comparison with other samples, samples treated with flaxseed protein showed the lowest reaction rate constant during chilled and frozen storage. The results confirmed that flaxseed protein with no sweetness and considerable caloric value had a cryoprotective effect similar to sucrose + sorbitol + polyphosphate and even better.

Comparative study on the effect of different salts on surimi gelation and gel properties

The effects of four representative salts, KCl, NaCl, CaCl2 and MgCl2, on surimi gel properties were comprehensively investigated. During gelation, monovalent salts are prone to convert α-helix to β-sheet while divalent salts tend to change α-helix to β-turn, thus altering the protein conformation differently. Monovalent salts extract and swell myofibrillar proteins more effectively, generating an ordered and smooth gel network with appreciable water-holding capacity (WHC). Ca2+ activates transglutaminase (TGase) to crosslink surimi proteins by forming ε-(γ-glutamyl) lysine bonds, while Mg2+ forms salt bridges with adjacent proteins, leading to a gel with more developed protein complexes. However, excessive divalent salts would induce serious protein coagulation, forming poor networks and lowering water retention. Ionic strength within 0.2–0.5 effectively reinforced the gel structure, while the WHC of surimi gels reached its peak with an ionic strength of around 0.6. At the optimal salt concentration of 1.5%, K+ with a larger ionic radius showed inferior effects on forming ionic bonds among proteins, whereas other metal ions induced more hydrophobic interactions within surimi gels. Mg2+, with higher oxidability than other metal ions, could enhance the formation of disulfide bonds and inhibit the browning caused by the Maillard reaction, thus improving gel whiteness. This study provides new insides into the roles of common salts during surimi gelation and gel properties and is expected to guide further gelation innovation and gel product development.

Effects of explosion puffing on surimi-starch blends: Structural characteristics, physicochemical properties, and digestibility

This study investigated the influence of different explosion puffing pressures (0.6 MPa-1.0 MPa) on the structural characteristics, physicochemical characteristics, and digestibility of surimi-starch blends. With increased explosion puffing pressures, the starch granules attached to the protein network and bound to the protein increasingly tight. The results of X-ray diffraction and Fourier-transform infrared spectroscopy (FTIR) showed that explosion puffing destroyed ordered starch molecule chains resulting in a starch structure chaos. In addition, explosion puffing reduced the secondary structure number of surimi proteins by loosening intramolecular hydrogen bonds. The explosion puffing decreased the digestibility of puffed surimi-starch blends, while increased the resistant starch content. Maillard reaction in the puffing process led to the browning of the surimi-starch blends. the surimi-starch blends exhibited the optimal qualities with homogeneous pore structure, good color (70.11), excellent crispness (25.55 mm), desirable hardness (1967.57 Pa), and high expansion rate (398.85%) at explosion pressure 0.8 MPa. Our findings provide a reference for processing non-fried high-protein puffed food.

Physicochemical properties of grass carp surimi as affected by pH and NaCl concentration during washing

ABSTRACT The objective of this study was to investigate the effects of various pHs and NaCl concentrations on physicochemical properties of surimi from grass carp during washing. Surimi protein recovery was higher with 0.25% and 0.5% NaCl at the pH 5 or 7 than that with other pHs and NaCl concentrations, while the highest recovery was obtained with 0.25% NaCl at the pH 7. It decreased protein recovery and salt-soluble protein of surimi as NaCl increased by more than 1.0% during washing. The water-soluble protein content was significantly higher at the pH 3 than at other pHs, while the SDS-PAGE of surimi protein exhibited intense sarcoplasmic protein bands at the pH 3. There were significantly fewer hydrophobic groups of actomyosin treated with 0.25% NaCl at the pH 5 or 7 than that with other pHs and NaCl concentrations in washing solution. The α-helix of actomyosin was increased with the increase of NaCl during washing. In general, the washing with 0.25%−0.5% NaCl at the pH 5–7 could significantly increase the yield of surimi from grass carp.

Effect of water-retention agents on Scomberomorus niphonius surimi after repeated freeze–thaw cycles: low-field NMR and MRI studies

Abstract Repeated freeze–thaw cycles can directly cause the changes in the water distribution, physicochemical characteristics, and microstructure of Scomberomorus niphonius surimi. To improve the quality of S. niphonius surimi, the effect of water retention agents (phosphate and trehalose) was investigated during freeze-thaw cycles. The results of low-field nuclear magnetic resonance (LF-NMR) combined with magnetic resonance imaging (MRI) analysis showed that the water retention agents could obviously decrease the water loss and water mobility during repeated freeze–thaw cycles. Water retention agent significantly reduced the cook loss and improved the surimi quality by decreasing the surimi protein denaturation. The scanning electron microscopy (SEM) characterization revealed that water retention agents could obviously ameliorate the protein structure damage. In addition, the principal component analysis combined with LF-NMR parameters showed clear discrimination between samples supplemented with different water retention agents. In a word, the LF-NMR and MRI might provide useful information in a non-invasive manner for monitoring the effects of water-retention agents on surimi after repeated freeze–thaw cycles.

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 active ice nucleation bacteria on freezing and the properties of surimi during frozen storage

The effects of active ice nucleation bacteria (INB, Pseudomonas syringae) on freezing, ice crystal formation, and aggregation, and oxidation of surimi from Talang queenfish (Scomberoides commersonnianus) during frozen storage were investigated. The shortest freezing time (225 min) and the highest onset temperature (−7.0 °C), as determined by differential scanning calorimetry (DSC), was found for surimi with 106 colony-forming units of INB mL−1 100−1 g (INB c1). The surimi showed better structure with the lowest inter-fiber space along with finer and more homogenous myofibrillar proteins (MP) surface morphology and a lower root-mean-square (Rq, 142 nm) from atomic force microscopy (AFM) after 90 days of storage at −18 °C, which was associated with the highest ζ-potential (−9.0 mV) than the control (−6.2 mV) which reflected a lowered MP aggregation behavior. Compared to the control, protein carbonyls in surimi with INB c1 decreased significantly, while showing a lower decrease in total sulfhydryl groups (P < 0.05). Overall, INB c1shortened the freezing time and increased freezing rate, while decreasing oxidation and aggregation of surimi proteins.

Inulin for surimi gel fortification: Performance and molecular weight-dependent effects

Inulin is a prebiotic carbohydrate widely used in food industry due to its health benefits and unique rheological properties. For the first time, this study explores the potential of natural inulin as a sustainable food additive to enhance surimi gel characteristics, specifically focusing on understanding its molecular weight effects. The good solubility of inulin facilitates the conversion of α-helix to other secondary conformations which are favorable for protein denaturation and aggregation during gelation. Moreover, the abundant –OH groups at the surface of inulin can boost the chemical forces within surimi proteins to reinforce the gel network. Compared to short-chain inulin, long-chain inulin can alleviate proteolysis, enhance hydrophobic interactions and intertwine with myosin molecules, thereby reinforcing the gel network. A more viscous long-chain inulin solution formed within surimi gels fills the space between aggregated proteins and facilitates the lock of water molecules, improving the water-holding capacity (WHC). Thus, an addition of 12 % long-chain inulin leads to an enhanced hardness of surimi gel from 943 to 1593 and improved WHC from 72 % to 85 %. A new inulin-myosin interaction mechanism model is also proposed to provide useful guidelines for surimi processing and expanding the application of inulin within the food industries.

Influence of L-arginine addition on the gel properties of reduced-salt white leg shrimp (Litopenaeus vannamei) surimi gel treated with microbial transglutaminase

This study aimed to investigate the effects of l-arginine (L-Arg) on the gel properties of reduced-salt shrimp surimi gel (SSG) treated with microbial transglutaminase (MTGase). The results showed that replacing NaCl with different concentrations of L-Arg in reduced-salt (0.5% NaCl) shrimp surimi treated with MTGase significantly increased the gel strength and texture of SSG, even at low L-Arg (0.5%) concentrations. However, 0.5% L-Arg added alone under low-salt conditions did not significantly improve the gel strength of SGG compared with the control SSG containing 0.5% NaCl. L-Arg and MTGase added together significantly increased the disulfide bonds and protein β-sheet structure of SSG while improving the moisture distribution and rheological properties. The electrophoretic analysis and microstructure images revealed that L-Arg and MTGase together promoted the cross-linking of proteins in shrimp surimi to form a dense gel network structure. In conclusion, the combined treatment of L-Arg and MTGase significantly improved the gel properties of SSG and reduced the amount of NaCl. Therefore, the combined treatment of L-Arg and MTGase could enhance the quality of reduced-salt shrimp surimi products.

Comparative Effect of Cricket Protein Powder and Soy Protein Isolate on Gel Properties of Indian Mackerel Surimi.

This work comparatively investigated the effects of different levels (0, 1, 3, and 5%, w/w) of cricket protein powder (CP) and soy protein isolate (SPI) on the gel properties of mackerel surimi. Both SPI and CP enhanced the rheological properties of surimi pastes during heating, as indicated by the increase in G' and G″ and the decrease in tan δ. With increasing SPI content, the proteolytic inhibition, gel properties, water-holding capacity, and textural profiles of surimi gel were markedly enhanced. Molecular driving-force results showed that SPI markedly promoted the hydrophobic interaction, while disulfide bonds were dominant in CP-added gel. However, the whiteness of surimi gels tended to decrease with the increased levels of both additives, in particular CP. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE) demonstrated that SPI hindered the polymerization of myosin heavy chain while CP participated in the formation of non-disulfide covalent bonds with actin. Fourier transform infrared (FTIR) spectra indicated that CP and SPI did not influence the secondary structure of proteins in surimi. Scanning electron microscopy (SEM) demonstrated that CP or SPI induced the myofibrillar protein to form smoother and compact gel network structures. Overall acceptability of the mackerel surimi gel can be improved by the incorporation of 5% SPI while CP had a negative impact on several parameters. However, CP showed the remarkable ability to prevent the lipid oxidation of the gel after storage at 4 °C for 7 days. Overall, both SPI and CP demonstrated positive impacts on the gelling characteristics of mackerel surimi; however, SPI was more advantageous than CP in terms of the gel-strengthening effect and sensory qualities. This study offered a potential use for plant and insect proteins as functional and nutritional ingredients for the production of dark-fleshed fish surimi.

Improving the Gel Quality of Threadfin Bream (Nemipterus spp.) Surimi Using Salted Duck Egg White Powder.

The effect of salted duck egg white powder (SDEWP) as a source of salt at different salt equivalent (SE) levels (0-2.5% SE) on gel qualities and texture properties of threadfin bream surimi was investigated. SDEWP possessed a high protein (64.59%) and salt (34.86%) concentration. The breaking force of surimi gel increased by the amount of SDEWP (p &lt; 0.05). The addition of SDEWP up to 1.5% SE into the surimi gel has significantly increased the deformation (13.8%) and decreased the expressible moisture content (38.5%). Hardness, gumminess, and chewiness were augmented as higher levels of SDEWP were added, whereas cohesiveness decreased when the SDEWP above 1.5% SE was used. The incorporation of SDEWP had no significant effect on the springiness (p &lt; 0.05). Less proteolytic degradation was observed in the surimi gel fortified with SDEWP. A higher amount of added SDEWP enhanced the whiteness of the surimi gel (p &lt; 0.05). A denser and more ordered gel network was attained when SDEWP with 1.5% SE was added. SDEWP could be exploited as a source for salt and non-fish proteins in threadfin bream surimi, in which SDEWP containing 1.5% SE could significantly improve the quality of surimi gel.

Seaweed Slurry Improved Gel Properties and Enhanced Protein Structure of Silver Carp (Hypophthalmichthys molitrix) Surimi.

In order to improve the gel quality of silver carp (Hypophthalmichthys molitrix) surimi, the texture and rheological properties and microstructure of silver carp surimi gel products were analyzed by adding Laminaria japonica (LJ), Undaria pinnatifida (UP) and Sargassum fusiforme (SF) slurries. After adding kelp slurry (KS), the gel strength reached the highest level of 1047.26 ± 85.04 (g·mm). The carbonyl content and surface hydrophobicity of surimi protein increased, while the free amino groups, total sulfhydryl groups, and fluorescence intensity decreased significantly. The results of transform infrared spectroscopy (FT-IR), circular dichroic (CD), and Raman spectra showed that the KS promoted the change of the secondary structure of protein. Scanning electron microscopy (SEM) images revealed that kelp slurry had a more compact gel microstructure. In conclusion, the kelp slurry could significantly increase the gel strength, improve the quality of surimi products, enrich the nutrition of silver carp surimi, and have great significance for expanding the application range of seaweed.

Effective role of konjac oligosaccharide against oxidative changes in silver carp proteins during fluctuated frozen storage

The aim of this research was to perform a comparative analysis of konjac oligosaccharides (KOG) and conventional cryoprotectant (4% sucrose + 4% sorbitol) mixture (positive control, PC) as an effective antioxidant during fluctuated (FLUC) frozen storage of silver carp proteins. The surimi proteins were added with PC, KOG (1%) and KOG (3%) and antioxidative abilities were analyzed during FLUC frozen storage. The Ca2+-ATPase, total and reactive sulfhydryl groups (SH) groups were significantly reduced in all samples due to denaturation of myosin globular head. The control (C) samples also showed increase in carbonyls from 29.36 to 49.11 nmol/mg during FLUC-I and from 29.81 to 46.09 nmol/mg during FLUC-II. Meanwhile, the PC sample and KOG (1 and 3%) significantly (P < 0.05) reduced the carbonyls and surface hydrophobicity by inhibiting the formation of disulfide bindings. The addition of KOG (3%) restricted the increase in surface hydrophobicity, decline in SH groups and Ca2+-ATPase than the PC and KOG (1%) added samples due to better and strong intermolecular interactions with protein molecules. Furthermore, KOG (3%) enhanced the gel strength of surimi by forming well-established and dense gel network of protein. Overall, KOG (3%) was found to be a potential substitute of PC for seafood frozen preservation and commercial benefits.

The interaction study of soluble pectin fiber and surimi protein network from silver carp (Hypophthalmichthys molitrix) based on a new prediction model

Pure surimi of silver carp (Hypophthalmichthys molitrix) cannot meet the texture requirements in novel 3D printing of food. In this work, the effect mechanism of adding soluble pectin fiber on the quality of surimi was studied at molecular scale, and the interaction has been discussed by a novel prediction model. In comparison with pure surimi, pH and water-holding capacity decreased with increasing pectin, and texture properties improved. The storage modulus firstly rose and then decreased, reaching a maximum value of 15012 Pa at 0.5 % pectin addition. The thermal transition temperature of myosin was moved from 52.13 to 49.80 °C. Pectin extended the T22 relaxation time, suggesting a decrease in immobilized water. A new Time-series prediction model and interaction analysis further explored the intrinsic correlation of various parameters of surimi with different pectin additions. This work contributes to add our understanding of pectin application in surimi products in future special dietary food.

Three-Dimensional Printing Properties of Polysaccharide Hydrocolloids-Unrinsed Sturgeon Surimi Complex Hydrogels.

Herein, the microstructure and mechanical properties of hydrogels consisting of unrinsed sturgeon surimi (URSS) and plant-derived polysaccharides such as κ-carrageenan (KC), konjac gum (KG), xanthan gum (XG), guar gum (GG) and sodium alginate (SA), were studied by texture analysis, rheological measurement and scanning electron microscopy (SEM). Rheological results showed that the apparent viscosity, storage modulus (G′) and loss modulus (G″) of URSS increased by addition of KC, KG, GG and SA. The gel strength of resultant surimi products fabricated with KG/URSS mixture was significantly higher than that of other groups. KG could significantly improve the hardness (44.14 ± 1.14 N), chewiness (160.34 ± 8.33 mJ) and cohesiveness (0.56 ± 0.02) of the unrinsed surimi gel. Adding SA and KC had no significant effect on the textural characteristics of printed gels. However, an apparent decrease in the relevant mechanical properties of printed hydrogels was observed when XG and GG were added into surimi. SEM indicated that the incorporation of KG and KC could further integrate the gel structure of URSS as compared to hindering the cross-linking of surimi protein by XG and GG, which were in accordance with gel strength and water-holding capacity. These results provided useful information to regulate the 3D printing performance in functionalized surimi-based material.

Thermal aggregation behavior of egg white protein and blue round scad (Decapterus maruadsi) myofibrillar protein.

In the present study, egg white protein (EWP) and myofibrillar protein (MP) were mixed in different ratios (0/100, 10/90, 20/80, 30/70, 40/60, 50/50, 100/0 for EWP/MP) and subjected to unheated, preheated (40°C/30min), two-step heated (40°C/30min, 90°C/20min), and one-step heated (90°C/20min) treatments to study the thermal aggregation of the two proteins. Their aggregation behavior was characterized by turbidity, active sulfhydryl, degree of protein cross-linking, protein characteristic spectra, and microscopic morphology. The results indicated that for the mixed protein system composed of EWP and MP, the mixed protein aggregation volume was larger and regular at an EWP/MP of 30/70, when the degree of cross-linking was best. When the ratio of EWP/MP was 50/50, the aggregate-protein interaction was dominant, and the excess EWP acted as a barrier to cross-linking and wrapped around the surface of the aggregates to form larger aggregates. Comparing the two-step heated and one-step heated conditions, the former is superior. PRACTICAL APPLICATION: The combination of egg white protein and myofibrillar protein can provide a theoretical reference for the protein content in surimi products, and moderate addition has an enhancing effect on surimi protein cross-linking and promotes gel formation. Excessive addition will form aggregates outside the egg white protein wrapping phenomenon, and the quality of surimi gel products will be affected.

Impacts of agar gum and fucoidan on gel properties of surimi products without phosphate.

Phosphate is widely used in surimi products to improve the gel properties. However, excess addition of phosphate occurs, which can harm the consumer's health. This study aimed to evaluate the effects of agar gum and fucoidan on maintaining the gel properties of surimi products instead of phosphate. Interestingly, our results showed that 0.125% of agar gum and fucoidan to replace phosphate could enhance water-holding capacity and maintain gel strength and textual properties of surimi products well. Especially at frozen storage for 1year, 0.125% of agar gum reduced the expressible moisture content of surimi products by around 10% (p < .05). Sensory evaluation showed that 0.125% of agar gum and fucoidan instead of phosphate can improve tissue and fondness of surimi products in refrigerated storage for 24 h but not in frozen storage for 1year. The addition of agar gum and fucoidan at a high concentration >0.50% increased the WHC, but significantly decreased gel strength and springiness of surimi products (p < .05). Particularly, 1.00% of agar gum and fucoidan reduced gel strength by around 20% (p < .05). It might be due to the destruction of the gel network structure of surimi protein following the excess addition of these polysaccharides. It can be concluded that 0.125% of agar gum and fucoidan can replace phosphate to develop high-quality surimi products, and excessive addition of them have negative effects.