Tracking aggregation behaviour and gel properties induced by structural alterations in myofibrillar protein in mirror carp (Cyprinus carpio) under the synergistic effects of pH and heating

Effect of sanxan as novel natural gel modifier on the physicochemical and structural properties of microbial transglutaminase-induced mung bean protein isolate gels

Mung bean protein isolate (MBPI) has attracted much attention as an emerging plant protein. However, its application was limited by the poor gelling characteristics. Thus, the effect of sanxan (SAN) on the gelling behavior of MBPI under microbial transglutaminase (MTG)-induced condition were explored in this study. The results demonstrated that SAN remarkably enhanced the storage modulus, water-holding capacity and mechanical strength. Furthermore, SAN changed the microstructure of MBPI gels to become more dense and ordered. The results of zeta potential indicated the electrostatic interactions existed between SAN and MBPI. The incorporation of SAN altered the secondary structure and molecular conformation of MBPI, and hydrophobic interactions and hydrogen bonding were necessary to maintain the network structure. Additionally, in vitro digestion simulation results exhibited that SAN remarkably improved the capability of MBPI gels to deliver bioactive substances. These findings provided a practical strategy to use natural SAN to improve legume protein gels.

Unraveling the binding mechanism between soybean protein isolate and selected bioactive compounds

The present study was aimed to investigate the interactions between soybean protein isolate (SPI) with resveratrol (RESV) and lutein (LUT). The binding forces, molecular interactions and functional properties were explored by multi-spectroscopic analysis, molecular docking and functional property indexes between SPI and RESV/LUT. The RESV/LUT quenched SPI chromophore residues with static mechanism and the endothermic reaction. The SPI- RESV/LUT complexes were formed through hydrogen bond, electrostatic and hydrophobic interactions. Molecular docking confirmed van-der-Waals force as one of the important forces. The interaction of RESV/LUT led to SPI's secondary structure alterations with a decrease in α-helix and random coil and an increase in β-sheet and β-turns. RESV/LUT developed foaming and emulsifying properties of SPI and showed a significant decrease of the surface hydrophobicity with RESV/LUT concentrations increase attributed to SPI's partial unfolding. Our study exposed molecular mechanisms and confirmations to understand the interactions in protein- RESV/LUT complexes for protein industrial base promotion.

An unfolding/aggregation kinetic instructed rational design towards improving graft degree of glycation for myofibrillar protein

Glycation is an effective strategy for the application of myofibrillar protein (MP) in beverage formulas by improving water solubility. In conventional glycation, the efficiency was limited as MP-saccharides conjugates mostly produced at low temperature due to thermosensitivity. This study was aimed to explore unfolding/aggregation kinetics of MP, including aggregate behavior, structural characteristics, and micromorphology, which guided the selection of temperature for glycation. It was shown that 40 °C/47.5 °C were critical temperature for MP unfolding/aggregation, respectively. Accordingly, an innovative technology of glycation (cyclic continuous glycation, CCG) was established by combining such temperatures. The results confirmed that cyclic continuous heating (CCH) inhibited excessive exposure of sulfhydryl and hydrophobic groups impeding protein aggregation. Importantly, it was revealed that rational designed CCG promoted covalent binding of MP to glucose by regulating unfolding-aggregation balance, exhibiting higher glycation degree. Overall, CCG-modified MP is expected to motivate the application of meat proteins in food formulations.

Constructing myosin/high-density lipoprotein composite emulsions: Roles of pH on emulsification stability, rheological and structural properties

The emulsification activity of myosin plays a significant role in affecting quality of emulsified meat products. High-density lipoprotein (HDL) possesses strong emulsification activity and stability due to its structural characteristics, suggesting potential for its utilization in developing functional emulsified meat products. In order to explore the effect of HDL addition on emulsification stability, rheological properties and structural features of myosin (MS) emulsions, HDL-MS emulsion was prepared by mixing soybean oil with isolated HDL and MS, with pH adjustments ranging from 3.0 to 11.0. The results found that emulsification activity and stability in two emulsion groups consistently improved as pH increased. Under identical pH, HDL-MS emulsion exhibited superior emulsification behavior as compared to MS emulsion. The HDL-MS emulsion under pH of 7.0-11.0 formed a viscoelastic protein layer at the interface, adsorbing more proteins and retarding oil droplet diffusion, leading to enhanced oxidative stability, compared to the MS emulsion. Raman spectroscopy analysis showed more flexible conformational changes in the HDL-MS emulsion. Microstructural observations corroborated these findings, showing a more uniform distribution of droplet sizes in the HDL-MS emulsion with smaller particle sizes. Overall, these determinations suggested that the addition of HDL enhanced the emulsification behavior of MS emulsions, and the composite emulsions demonstrated heightened responsiveness under alkaline conditions. This establishes a theoretical basis for the practical utilization of HDL in emulsified meat products.

Characterization of bamboo shoots dietary fiber modified by ball milling and its role in altering the physicochemical properties of shrimp surimi

A simple but robust strategy of ball milling (20 Hz, 30 Hz for 30 s, 60 s, 120 s, 180 s) was utilized to modify bamboo shoots fiber (BSDF) in shrimp surimi. The water holding capacity, swelling capacity, and oil binding capacity of 30 Hz-60 s milled BSDF exhibited the highest values of 5.61 g/g, 3.13 mL/g, and 6.93 g/g, significantly higher (P < 0.05) than untreated one (3.65 g/g, 2.03 mL/g, 4.57 g/g). Ball-milled BSDF exhibited a small-sized structure with the relative crystallinity decreased from 40.44 % (control) to 11.12 % (30 Hz-180 s). The myosin thermal stability, gelation properties of surimi were significantly enhanced by incorporating 20 Hz-120 s and 30 Hz-60 s BSDF via promoting protein unfolding, covalent hydrophobic interactions, and hydrogen bonding. A matrix-reinforcing and water entrapping effect was observed, exhibiting reinforced networks with down-sized water tunnels. However, BSDF modified at 180 s contributed to over-aggregated networks with fractures and enlarged gaps. Appropriate ball-milled BSDF (20 Hz-120 s, and 30 Hz-60 s) resulted in a significant decrease in α-helix (P < 0.05), accompanied by an increase of β-sheets and β-turn. This work could bring some insights into the applications of modified BSDF and its roles in the gelation of surimi-based food.

Performance and protein conformation of thermally treated silver carp (Hypophthalmichthys molitrix) and scallop (Argopecten irradians) blended gels

BACKGROUND

The quality of surimi-based products can be improved by combining the flesh of different aquatic organisms. The present study investigated the effects of incorporating diverse ratios of unwashed silver carp (H) and scallop (A) and using various thermal treatments on the moisture, texture, microstructure, and conformation of the blended gels and myofibrillar protein of surimi.

RESULTS

A mixture ratio of A:H = 1:3 yielded the highest gel strength, which was 60.4% higher than that of scallop gel. The cooking losses of high-pressure heating and water-bath microwaving were significantly higher than those of other methods (P < 0.05). Moreover, the two-step water bath and water-bath microwaving samples exhibited a more regular spatial network structure compared to other samples. The mixed samples exhibited a microstructure with a uniform and ordered spatial network, allowing more free water to be trapped by the internal structure, resulting in more favorable gel properties. The thermal treatments comprehensively modified the tertiary and quaternary structures of proteins in unwashed mixed gel promoted protein unfurling, provided more hydrophobic interactions, enhanced protein aggregation and improved the gel performance.

CONCLUSION

The findings of the present study improve our understanding of the interactions between proteins from different sources. We propose a new method for modifying surimi's gel properties, facilitating the development of mixed surimi products, as well as enhancing the efficient utilization of aquatic resources. © 2024 Society of Chemical Industry.

Thermal aggregation behavior of silver carp myofibrillar protein at low salt content: Effect of oat β-glucan combined with ultrasound-assisted heating

The effects of oat β-glucan (OG) combined with ultrasound-assisted treatment on thermal aggregation behavior of silver carp myofibrillar protein (MP) under low salt concentration were investigated. The particle size and turbidity of MP were increased to higher levels by OG participation or ultrasound treatment during the two-stage heating. Both OG and ultrasonic treatment promoted the unfolding of MP structure, evidenced by the gradual decrease of α-helix content and fluorescence intensity, as well as the increase of β-sheet content, surface hydrophobicity and sulfhydryl content. Compared to solely OG or ultrasonic treatment, the combination of OG and ultrasound further promoted the unfolding of MP and more sulfhydryl groups were exposed in the pre-heating stage, which was conducive to strengthen the chemical forces between MP molecules. Additionally, AFM analysis revealed that the apparent morphology of the OG combined with ultrasonic treated group exhibited a smoother surface and a more uniform distribution of aggregates.

κ-Carrageenan masking bitterness perception in surimi gels containing potassium chloride-based salt substitutes: Gel properties, oral processing, and sensory evaluation

κ-Carrageenan (CG) was employed to mask the bitterness induced by 50% KCl in surimi gels to achieve salt reduction and gel performance improvement. The combination of KCl and CG (KCl + CG) yielded the increased textural characteristics and water-holding capacity (WHC) of surimi gels and facilitated the transition of free water to immobilized water. In addition, the KCl + CG supplement increased the turbidity and particle size of myofibrillar protein (MP) sols but decreased the surface hydrophobicity in a dose-dependent manner. The hydrophobic interactions and disulfide bonds played crucial roles in maintaining the stability of MP gels. The specific binding of potassium ions to the sulfate groups of CG limited the release and diffusion of potassium ions from the surimi gels during oral processing, effectively masking the bitterness perception and maintaining the saltiness perception. This study provides a promising strategy to reduce the utilization of sodium salt in surimi products.

Optimizing the formation of myosin/high-density lipoprotein composite gels: PH-dependent effects on heat-induced aggregation

This study investigated impact of high-density lipoprotein (HDL) on thermal aggregation and gelling behavior of myosin in relation to varied pHs. Results revealed that HDL modified myosin structure before and after heating, with distinct effects observed at varied pH. Under pH 5.0, both myosin and HDL-MS exhibited larger aggregates and altered microstructure; at pH 7.0 and 9.0, HDL inhibited myosin aggregation, resulting in enhanced solubility, reduced turbidity and particle size. Comparative analysis of surface hydrophobicity, free sulfhydryl groups and secondary structure highlighted distinct thermal aggregation behavior between MS and HDL-MS, with the latter showing inhibitory effects under neutral or alkaline conditions. Gelation behavior was enhanced at pH 7.0 with maximum strength, hardness, water-holding capacity and rheological properties. Under acidic pH, excessive protein aggregation resulted in increased whiteness and rough microstructure with granular aggregates. Under alkaline pH, gel network structure was weaker, possibly due to higher thermal stability of protein molecules. Scanning electron microscopy revealed expanded HDL protein particles at pH 7.0, accounting for decreased gel strength and altered rheological properties compared with myosin gel. Overall, the results indicated a positive role of HDL at varied pH in regulating thermal aggregation of myosin and further impacting heat-induced gel characteristics.

Effect of Static Magnetic Field on the Quality of Pork during Super-Chilling Storage

Fresh pork tenderloin was stored at -3 °C under different static magnetic fields (SMF) of 0, 4, and 10 mT (control, MF-4, and MF-10) to investigate their physicochemical properties changes during storage of 8 days. The initial equilibrium temperature of the samples stored with 4 mT MF was found to be -2.3 °C, which was slightly lower (0.3 °C) than that the control value. The super-chilling phenomenon on the pork was then observed, as the samples stored under the magnetic field did not freeze throughout storage period, but the control experienced a sudden change in temperature after 138 h and then froze. The preservation effect of MF-4 on meat quality was the best in all treatment groups. MF-4 achieved a higher water-retention rate, with drip and cook losses of 6.5% and 29.0% lower than the control, respectively. Meanwhile, the MF-4 effectively delayed the color change in the meat during the storage and the texture hardening after cooking, and effectively controlled the growth of the total volatile saline nitrogen content on the samples. In addition, MF-4 delayed the reduction in myofibrillar protein solubility, sulfhydryl content, and emulsification capacity, indicating that this field inhibited the denaturation of myofibrillar protein. This study can be considered as an application reference of magnetic fields during meat storage at a super-chilled temperature.

Low-voltage electrostatic field enhances the frozen force of -12 ℃ to suppress oxidative denaturation of the lamb protein during the subsequent frozen storage process after finishing initial freezing

The effect of low-voltage electrostatic field (LVEF) assisted -9 °C (LVEF-9) and -12 °C (LVEF-12) frozen, non-LVEF-assisted -9 °C (NLVEF-9) and -12 °C (NLVEF-12) frozen, and conventional frozen (CF-18, -18 °C) storage on the muscle microstructure and the oxidative denaturation of the lamb protein during the subsequent frozen storage process after finishing initial freezing was investigated. Compared with NLVEF-9, LVEF-9, and NLVEF-12, LVEF-12 maintained the better integrity of muscle microstructure, demonstrated by smaller holes, more complete Z-line and M-line, and no significant difference with CF-18 (P > 0.05). Furthermore, LVEF-12 effectively inhibited protein oxidative denaturation as shown by the lower carbonyl content, surface hydrophobicity, and higher total/active sulfhydryl groups and Ca2+-ATPase activity. Moreover, LVEF-12 effectively maintained the integrity of the secondary and tertiary structure of proteins, reduced cross-linking aggregation of proteins, and sustained better functional properties, as shown by higher α-helix content, fluorescence intensity, protein solubility, and lower R-value, disulfide bonds.

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.

Heat-induced agglomeration of water-soluble cod proteins toward gelled structures

Cod proteins (CPs) have potential applications in designing desirable gel-based products, and this study aimed to unravel their heat-induced aggregation pattern and further probe the roles in protein gels. SDS-PAGE analysis indicated that high-precipitation-coefficient aggregates (HPCAs) of CPs aggregates were composed of considerable polymers of myosin heavy chains and actin, and their low-precipitation-coefficient aggregates (LPCAs) contained myosin light chains and tropomyosin. Studies from correlation analysis between the structure and aggregation kinetics revealed that the generation of β-sheet and SS bonds were responsible for their spontaneous thermal aggregation induced by heating temperature and protein concentration, respectively. Additionally, as protein denaturation ratio increased, more and larger HPCAs were formed, which was evidenced driving the network formation of protein gels and resulting in higher storage modulus (G') values. These novel findings may be applicable to other animal proteins for better tailoring the manufacturing of muscle gel-based products.

Effect of dynamic high-pressure microfluidization treatment on soybean protein isolate-rutin non-covalent complexes

In this investigation, soybean protein isolate-rutin (SPI-RT) complexes were treated using dynamic high-pressure microfluidization (DHPM). The effects of this process on the physicochemical and thermodynamic properties of SPI were investigated at different pressures. Fourier-transform infrared spectroscopy and fluorescence spectroscopy provided evidence that the SPI structure had been altered. The binding of SPI to RT resulted in a decrease in the percentage of α-helices and random curls as well as an increase in the percentage of β-sheets. In particular, the α-helix content decreased from 29.84 % to 26.46 %, the random curl content decreased from 17.45 % to 15.57 %, and the β-sheet content increased from 25.37 % to 26.53 %. Moreover, fluorescence intensity decreased, and the emission peak of the complex was red-shifted by 6 nm, exposing the internal groups. Based on fluorescence quenching analysis, optimal SPI-RT complexation was achieved after 120-MPa DHPM treatment, and molecular docking analysis verified the interaction between SPI and RT. The minimum particle size, maximum absolute potential, and total phenolic content of the complexes were 78.06 nm, 21.4 mV and 74.35 nmol/mg protein, respectively. Furthermore, laser confocal microscopy revealed that the complex particles had the best microstructure. Non-covalent interactions between the two were confirmed using sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Moreover, the hydrophobicity of the complex particle's surface increased to 16,045 after 120-MPa DHPM treatment. The results of this study suggest that DHPM strongly promotes the improvement of the physicochemical properties of SPI, and provide a theoretical groundwork for further research.

Improved emulsifying properties of water-soluble myofibrillar proteins at acidic pH conditions: Emphasizing pH-regulated electrostatic interactions with chitosan

Water-soluble muscle protein with enhanced functionalities has attracted great interest for low-salt food design. Electrostatic interactions of chitosan (CS) with myofibrillar proteins (MP) in water-aqueous solution at acidic pHs (4.0-6.5) were investigated, and how pH regulated complex formation, microstructures, conformation changes, and emulsifying capacity was systematically explored. At pH 4.0-4.5, MP and CS were positively charged and displayed a co-soluble system, exhibiting small particles and high solubility. When the pH increased to near the isoelectric point (pI) of MP (pH 5.0-6.0), electrostatic interactions largely inhibited the aggregation of MP by forming smaller particle complexes. The flexible structures and improved amphiphilic properties promoted protein absorption at the oil-water interface, further improving the emulsion stability. When the pH increased to 6.5, large aggregates were formed causing poor functionalities. This study could provide great insights to further exploit meat-protein-based low-salt functional foods in novel food design.

Evaluation of the Emulsifying Property and Oxidative Stability of Myofibrillar Protein-Diacylglycerol Emulsions Containing Catechin Subjected to Different pH Values

Myofibrillar protein-diacylglycerol emulsions containing catechin (MP-DAG-C) possess outstanding emulsifying property and oxidative stability. However, the effect of pH on MP-DAG-C emulsions should be revealed to provide possibilities for their application in practical meat products. Therefore, MP-DAG-C emulsions at different pH values were used in this study, in which lard, unpurified glycerolytic lard (UGL), and purified glycerolytic lard (PGL) were used as the oil phases. The results indicated that the emulsifying property of the UGL- and PGL-based emulsions increased compared to those of the lard-based emulsions (p < 0.05). The emulsifying activity and stability indices, absolute value of ζ-potential, and rheological characteristics increased with the increase in pH values (p < 0.05), with the droplets were smallest and distributed most uniformly at a pH of 6.5 compared to the other acidic environment (p < 0.05). The thiobarbituric acid substance and carbonyl content increased (p < 0.05), while the total sulfydryl content decreased (p < 0.05) during storage. However, there was no statistical difference between the oxidative stability of the MP-DAG-C emulsions with different pH values (p > 0.05). The results implied that the emulsifying property of MP-DAG-C emulsions increased with an increase in pH values. The oxidative stability of the MP-DAG-C emulsions at high pH values was improved by catechin.

Protein oxidation-mediated changes in digestion profile and nutritional properties of myofibrillar proteins from bighead carp (Hypophthalmichthys nobilis)

Digestibility is an important factor in accessing the nutritional quality and potential health benefits of protein. In this study, exudates were utilized to incubate myofibrillar proteins (MPs) for simulating the oxidation of MPs in frozen-thawed fish fillets. An in vitro gastrointestinal system was used to investigate the effect of protein oxidation on the digestion profile and nutritional properties of MPs. Results showed that exudates treatment caused the moderate oxidation of MPs and its digestibility thus increased, hydroxyl radical generation system treatment reduced the digestibility significantly. The analysis of SDS-PAGE, tricine-SDS-PAGE, amino acid composition, and peptidomics of digestion products indicates that protein oxidation decreases digestibility by causing protein cross-linking, degradation, and amino acid residues conversion. Additionally, protein oxidation reduces nutritional value of MPs via several ways including loss of essential amino acids, the proportion increase of macromolecular peptides (>2 kDa) in digests, and the percentage decrease of potential bioactive peptides in digests. The present study provides an intuitive insight into the impact of protein oxidation in frozen/thawed fillets on the digestibility of MPs, emphasizing the importance of mitigating protein oxidation to preserve their nutritional quality.

Effect of protein structure changes during different power ultrasound thawing on emulsification properties of common carp (Cyprinus carpio) myofibrillar protein

The impact of ultrasound thawing (UT) at different power (0 W, 100 W/0.132 W·cm-2, 300 W/1.077 W·cm-2, and 500 W/1.997 W·cm-2, namely WT, UT-100, UT-300, and UT-500) on protein structure, aggregation, and emulsifying properties of common carp (Cyprinus carpio) myofibrillar protein were investigated in the present study. The result showed that the reactive sulfhydryl content, total sulfhydryl content, protein solubility, and absolute potential of UT-300 samples were obviously higher than those of other thawed samples, while the turbidity of UT-300 samples was lower (P < 0.05), which indicated that proper UT power was beneficial to inhibit protein aggregation caused by thawing, while too low (100 W) or too high (500 W) ultrasonic power had poor effect. The Ca2+-ATPase activity and thermal stability of UT-300 samples were much higher than those of other thawed samples (P < 0.05), indicating that UT-300 inhibited myosin denaturation and thermal stability reduction of thawed products. The α-helix content of UT-300 samples was higher than that of other thawed samples, while the β-sheet content was significantly lower than that of other thawed samples (P < 0.05). The fluorescence intensity of UT-300 samples was higher than that of other thawed samples, and the λmax of UT-300 samples and UT-100 samples were lower than that of other thawed samples, which indicated that UT-300 could effectively inhibit the alteration of protein secondary structure and tertiary structure during thawing. The emulsifying activity of UT-300 samples was significantly higher than that of WT samples, and the droplet diameter of UT-300 samples was also lower than that of WT samples (P < 0.05), which indicated that UT-300 inhibited the decrease of emulsifying property during thawing. Overall, moderate ultrasonic power (300 W) could effectively inhibit the protein aggregation and structural changes during thawing, led to the decrease of emulsifying activity.

Mechanism on the Synergistic Gelation of the Myofibrillar Protein Composite Gel Enhanced by "Clean-Label" Skin Functional Protein Powders

The concept of healthiness and sustainability has promoted the innovation and development of "clean-label" products. Herein, this study aims to explore the influence mechanism of "clean label" skin protein powder (FPP) on the gelation properties of myofibrillar proteins (MPs). Specifically, the addition of FPP (0.2-4.0%) can improve the water holding capability and texture properties of MP composite gels. When the FPP concentration is over 1.0%, the composite gels exhibit no significant water loss during centrifugation. Dynamic rheology and sodium-dodecyl sulfate-polyacrylamide gel electrophoresis results revealed that FPP can slow the aggregation and denaturation of myosin and promote the formation of disulfide bonds between myofibril proteins, thus forming a stable network structure. Structural observation revealed that FPP can fill into the MP gel and lead to the formation of compact gel structures. Besides, with the increase of FPP concentration, the chemical forces involved in structural stabilization change significantly. Specifically, hydrophobic interaction and hydrogen bonding are the dominant forces at a lower FPP concentration (0.2 and 0.4%), while the ionic bond and disulfide bond are the dominant forces at a higher concentration. Overall, this work demonstrated that FPP can significantly improve the gel functionality of MP by altering the gel structure and strengthening the molecular forces.

Cell-Free Supernatant of Lactiplantibacillus plantarum 90: A Clean Label Strategy to Improve the Shelf Life of Ground Beef Gel and Its Bacteriostatic Mechanism

Lactic acid bacteria metabolites can be used as a clean-label strategy for meat products due to their "natural" and antibacterial properties. In this study, the feasibility of using cell-free supernatant of Lactiplantibacillus plantarum 90 (LCFS) as a natural antibacterial agent in ground beef was investigated. The sensitivity of LCFS to pH, heat and protease, as well as the changes of enzyme activities of alkaline phosphatase (AKP) and Na+/K+-ATP together with the morphology of indicator bacteria after LCFS treatment, were analyzed to further explore the antibacterial mechanism of LCFS. The results showed that the addition of 0.5% LCFS inhibited the growth of microorganisms in the ground beef gel and extended its shelf-life without affecting the pH, cooking loss, color and texture characteristics of the product. In addition, the antibacterial effect of LCFS was the result of the interaction of organic acids and protein antibacterial substances in destroying cell structures (cell membrane, etc.) to achieve the purpose of bacteriostasis. This study provides a theoretical basis for the application of LCFS in meat products and a new clean-label strategy for the food industry.

Whey Protein Hydrolysate Improved the Structure and Function of Myofibrillar Protein in Ground Pork during Repeated Freeze-Thaw Cycles

Whey protein hydrolysate (WPH) has made a breakthrough in inhibiting oxidative deterioration and improving the quality of meat products during storage. Based on our previous study of extracting the most antioxidant active fraction I (FI, the molecular weight < 1 kDa) from whey protein hydrolysates of different molecular weights, the present study continued to delve into the effects of WPH with fraction I on the structure and function of myofibrillar proteins (MP) in ground pork during the freeze-thaw (F-T) cycles. With the number of F-T cycles raised, the total sulfhydryl content, the relative contents of α-helix, Ca2+-ATPase activity, K+-ATPase activity, solubility, emulsion activity index (EAI), and emulsion stability index (ESI) of MP gradually decreased. Conversely, the carbonyl content and the relative content of random curl showed an increasing trend. In particular, the damage to the structure and the function of MP became more pronounced after three F-T cycles. But, during F-T cycles, FI stabilized the structure of MP. Compared to the control group, the 10% FI group showed a remarkable improvement (p < 0.05) in the total sulfhydryl content, Ca2+-ATPase activity, K+-ATPase activity, solubility, EAI and ESI after multiple F-T cycles, suggesting that 10% FI could effectively inhibit protein oxidation and had the influence of preserving MP function properties. In conclusion, WPH with fraction I can be used as a potential natural antioxidant peptide for maintaining the quality of frozen processed meat products.

Physicochemical and structural changes of myofibrillar proteins in muscle foods during thawing: Occurrence, consequences, evidence, and implications

Myofibrillar protein (MP) endows muscle foods with texture and important functional properties, such as water-holding capacity (WHC) and emulsifying and gel-forming abilities. However, thawing deteriorates the physicochemical and structural properties of MPs, significantly affecting the WHC, texture, flavor, and nutritional value of muscle foods. Thawing-induced physicochemical and structural changes in MPs need further investigation and consideration in the scientific development of muscle foods. In this study, we reviewed the literature for the thawing effects on the physicochemical and structural characters of MPs to identify potential associations between MPs and the quality of muscle-based foods. Physicochemical and structural changes of MPs in muscle foods occur because of physical changes during thawing and microenvironmental changes, including heat transfer and phase transformation, moisture activation and migration, microbial activation, and alterations in pH and ionic strength. These changes are not only essential inducements for changes in spatial conformation, surface hydrophobicity, solubility, Ca2+ -ATPase activity, intermolecular interaction, gel properties, and emulsifying properties of MPs but also factors causing MP oxidation, characterized by thiols, carbonyl compounds, free amino groups, dityrosine content, cross-linking, and MP aggregates. Additionally, the WHC, texture, flavor, and nutritional value of muscle foods are closely related to MPs. This review encourages additional work to explore the potential of tempering techniques, as well as the synergistic effects of traditional and innovative thawing technologies, in reducing the oxidation and denaturation of MPs and maintaining the quality of muscle foods.

Effect of different stunning methods on antioxidant status, myofibrillar protein oxidation, and gelation properties of large yellow croaker during postmortem

Post-mortem muscle biochemical processes play a crucial role on fish fillets quality and they are strictly linked to stunning methods. The improper stunning methods before slaughter could cause the fish to deteriorate more quickly during cold storage. This study aimed to investigate the effect of stunning methods (hit on the head, T₁; gill cut, T₂; immersion in ice/water slurry, T₃; CO₂ narcosis, T₄; 40% CO₂ + 30 % N₂ + 30% O₂, T₅) on myofibrillar proteins (MPs) of large yellow croaker. The results indicated that T₂ and T₃ samples were significantly damaged compared with other samples, which reflected that the activities of total superoxide dismutase (SOD), catalase (CAT), and glutathione peroxidase (GPx) were significantly damaged during cold storage in T₂ and T₃ samples. And the gill cut and immersion in ice/water slurry resulted in the generation of protein carbonyl, the decrease of Ca²⁺-ATPase, free ammonia and protein solubility, and the production of dityrosine during storage. In addition, MPs gel of T₂ and T₃ samples showed the decrease of water hold capacity (WHC) and whiteness, structure destruction, and water migration. The T₄ samples had the least damage of MPs and gel structure during cold storage.

Mechanism for improving the gel properties of transglutaminase-mediated porcine myofibrillar protein by ultrasonic pretreatment combined with carrageenan

To improve the limitation of transglutaminase on the quality of myofibrillar protein (MP) gel, this study investigated the synergistic effect of ultrasonic pretreatment in combination with carrageenan on the gel properties of transglutaminase-mediated MP gels. The synergistic effect generated gel with lower surface hydrophobicity and fluorescence intensity. Combined with the secondary structure results, it can be hypothesized that the synergistic effect caused the rearrangement of the proteins and the formation of aggregates wrapping hydrophobic groups, which changed the structure and phase behavior of the proteins. The synergistic effect also improved the formation of dense and interpenetrating gel networks, which reduced cooking loss and produced composite MP gels with optimal gel strength. Moreover, FTIR spectroscopy revealed the presence of electrostatic interactions in the hybrid gel system. This study provides a theoretical basis and experimental foundation for the effective use of high-tech composite functional components to improve the quality of gel products.

Effects of alternating electric field assisted freezing-thawing-aging sequence on longissimus dorsi muscle microstructure and protein characteristics

The current study investigates the influence of alternating electric field (AEF)-assisted freezing-thawing-aging sequence on the muscle microstructure and myofibrillar protein characteristics. Three treatments were used for longissimus dorsi (LD) muscle: only aging (OA), freezing-thawing-aging sequence (FA) and AEF-assisted freezing-thawing-aging sequence (EA). Compared with the FA and EA groups, the OA group showed considerably fewer cracks between muscle fibers and maintained the integrity of the Z-line as observed using scanning and transmission electron microscopy, respectively. Furthermore, the EA treatment effectively decreased myofibrillar fragmentation, myofibrillar protein aggregation, and protein oxidation, as shown by the myofibrillar fragmentation index, turbidity, and total sulfhydryl concentration. Analysis of surface hydrophobicity and the Fourier transform infrared, UV absorption, and fluorescence spectrums indicated that AEF minimized the alterations of protein secondary and tertiary structure alterations during aging after freezing.

Investigation of the physicochemical properties of the thin slices of dried pork meat paper mixed with squid

Globally, the Peruvian squid (Dosidicus gigas) has the highest productivity among squid species. However, due to its high-water content and astringent taste, it has limited fresh food value. This study used Peruvian squid meat as the primary material to prepare thin slices of dried squid meat paper mixed with pork. Here, different proportions (20, 40, 60, 80, and 100%, while 0% as the control group) of squid surimi have used to mix with pork for the meat paper preparation and the changes in physicochemical properties, microstructure, and sensory evaluation were analyzed. The results showed that the total volatile basic nitrogen (TVB-N) contents increased with the storage period, where 20% squid surimi substitution had the lowest TVB-N content. The 20% squid surimi substitution group had the highest expansion rate, the lowest peroxide value (PV), and moisture content. The food-borne microorganisms (E. coli, coliforms, and Salmonella spp.) were within the legal limits or negative. Hardness and crispiness, 20-40% squid surimi substitution were closely similar to the control group. This study has provided an effective investigation of the possibility of expanding the utilization of Peruvian squid resources by combining appropriate squid surimi with minced pork for high-quality thin slices of dried meat paper.

Impacts of soybean protein isolate hydrolysates produced at high hydrostatic pressure on gelling properties, structural characteristics, and molecular forces of myofibrillar protein

BACKGROUND

Soybean protein isolate hydrolysates (SPIHs) produced at high hydrostatic pressure have higher bioactivity. The aim of the study was to analyze the effects of different SPIH concentrations obtained under various pressures (0.1, 100, 200, and 300 MPa) on gelling properties, structural characteristics, and main forces of myofibrillar protein (MP) in MP-SPIH plural gels.

RESULTS

The MP-SPIH plural gel with 3% SPIH produced under 200 MPa had the maximum gel strength (0.42 N) and water holding capacity (53.69%). A decline in thermal stability and a rise in storage modulus (G') of MP-SPIH plural gels were found with increased SPIH pressure and concentration. Additionally, the addition of SPIHs increased the amounts of α-helix and β-sheet, decreased random coil structural content of MP in MP-SPIH plural gels, and facilitated the generation of a denser and uniform gels network. The molecular forces in MP-SPIH plural gels were mainly hydrophobic interaction and hydrogen bond.

CONCLUSION

This study showed that the interaction of MP with 3% SPIH obtained at 200 MPa improved the quality of plural gels. © 2022 Society of Chemical Industry.

The red, firm, non-exudative and pale, soft, exudative pork have different in vitro digestive properties of protein

Pale, soft and exudative (PSE) meat has worse edible quality than red, firm and non-exudative (RFN) meat, but their difference in nutritional values is still unclear. In this study, the differences in digestive properties between PSE and RFN pork were explored, and the potential mechanisms were analyzed in terms of protein conformation. The PSE pork showed significantly higher digestibility and smaller particle size compared with RFN pork (P < 0.05) after gastrointestinal digestion. Mechanistically, the lower viscosity was seen in the PSE pork digestion system. The protein structure of PSE pork was disordered with weaker hydrogen bond and ionic bond before and after heating. In addition, the protein (mainly salt-soluble protein) of PSE pork was highly oxidized. The results suggested that higher level of oxidation in PSE pork leads to the destruction of the molecular forces, resulting in the impaired protein conformation and disordered protein structure. The serial changes caused the meat proteins more accessible to digestive enzymes, thus improving the digestibility. The findings provide new insights into the evaluating the quality of PSE meat.

Evaluation and relationship analysis of pea protein on structure and heat-induced gel performance of myofibrillar protein

BACKGROUND

Surimi products occupy a large market in the food industry, and the gel performance is an important index to evaluate them. Thus, it is of great significance and practical value to find better food ingredients to regulate the structure and gel performance of surimi products. In this study, we used pea protein (PP) to restructure fish myofibrillar proteins (MPs) to achieve regulation of protein gel performance.

RESULTS

PP could enhance MP gel performance in terms of compressive strength, water-holding capacity, and some texture parameters. This may be the result of an increasing β-sheet content and a decreasing trend in the α-helix content, along with enhancements in hydrophobic interactions, nonspecific associations, and ionic bonds in a mixed PP-MP gel. The compressive strength, texture, and water-holding capacity of MP gel were positively correlated with surface hydrophobicity, active sulfhydryl, turbidity, and β-sheet of the mixed PP-MP system.

CONCLUSION

The findings suggest that PP can regulate the gel performance by remodeling the structure of MP. The regulation and correlation analysis between gel performance, structure, and physicochemical properties were explored and established to provide a theoretical basis for improving the quality of surimi products. This study will broaden the application of PP in the field of food processing and provide theoretical guidance for the manufacture of new surimi products. © 2023 Society of Chemical Industry.

Changes in Texture Characteristics and Special Requirements of Sichuan-Style Braised Beef for Industrial Production: Based on the Changes in Protein and Lipid of Beef

This study aimed to investigate the optimal stewing time (0, 30, 60, 90, 120, and 150 min) for industrialized preparation of Sichuan-style braised beef with different demands. With prolonged stewing time, the hardness and chewiness of the braised beef initially increased and then decreased (p < 0.05), whereas springiness and cohesiveness gradually decreased. The moisture content of braised beef and the endogenous fluorescence intensity of braised beef protein significantly decreased (p < 0.05). However, the thiobarbituric acid reaction substances (TBARS) value and protein carbonyl content of braised beef greatly increased (p < 0.05). During the stewing process, the texture properties of Sichuan-style braised beef were affected by the moisture content, oxidation of proteins and lipids, and integrity of the muscle fibers. Considering texture traits, when Sichuan-style pre-braised beef bought by consumers is stewed with other ingredients for about 30 min, its corresponding stewing time is 60 min in industrialized production processes. This process parameter can not only save energy consumption for practical production, but also improve the hardness value of the as-obtained Sichuan-style pre-braised beef, which is conducive to transportation through refraining from cracking of pre-braised beef pieces. When consumers only use simple heating to eat the Sichuan-style pre-braised beef product, stewing times of 120 or 150 min can be considered in industrialized production processes. This work provided a theoretical reference for the industrialized and standardized production of different types of prepared Sichuan-style braised beef.

Effect of Thermal Processing on the Conformational and Digestive Properties of Myosin

Heat treatment affects the structural properties of meat proteins, which in turn leads to changes in their sensitivity to digestive enzymes, further affecting the nutritional value of meat and meat products. The mechanism of changes in the structure and digestive properties of myosin under different heating conditions were studied. An increase in heating temperature led to the exposure of internal groups to a polar environment, but to a decrease in the sturdy α-helix structure of myosin (p < 0.05). The results of tryptophan fluorescence verified that the tertiary structure of the protein seemed to be unfolded at 70 °C. Higher protein denaturation after overheating, as proven by the sulfhydryl contents and turbidity, caused irregular aggregate generation. The excessive heating mode of treatment at 100 °C for 30 min caused myosin to exhibit a lower degree of pepsin digestion, which increased the Michaelis constant (Km value) of pepsin during the digestion, but induced the production of new peptides with longer peptide sequences. This study elucidates the effects of cooking temperature on the conformation of myosin and the change in digestibility of pepsin treatment during heating.

Elastic and transparent ovalbumin hydrogels formed via succinylation combined with pH-shifting treatment

Ovalbumin (OVA) is a model protein with extensive research on structure and function, however, the application of OVA in food processing is limited due to its low gelation properties. In this study, thermally-induced highly transparent and elastic hydrogels from OVA pretreated by succinylation combined with pH-shifting method were reported. Transmission electron microscope (TEM) and free sulfhydryl groups determination revealed that the pretreatment induced the stretching of the protein structure and promoted the formation of preliminary aggregates. Further heating the pretreated OVA suspension resulted in a homogeneous and macroporous gel network with thin connecting walls. Such homogeneous gel network structures may be related to the effective modulation of the thermal aggregation efficiency of proteins by succinylation and the high level of protein unfolding by pH-shifting treatments, which synergistically allowed for more active sites to be created during heating to facilitate intermolecular interactions, including hydrogen bonding and hydrophobic interactions. Notably, the method resulted in a 507.14% increase in elasticity, a 60.74% increase in water holding capacity of the OVA hydrogels compared to the native OVA hydrogels without pretreatment. Also, the hydrogels were transparent with 73.11% light transmittance. In conclusion, succinylation and pH-shifting combined treatment could be an effective method for the preparation of OVA hydrogels with superior gelation properties.

Improvement on gel properties of myofibrillar protein from chicken patty with potato dietary fiber: Based on the change in myofibrillar protein structure and water state

Influence of potato dietary fiber (PDF) on myofibrillar protein (MP) structure, aggregation behavior, and gel properties of chicken patty was evaluated. The Raman spectroscopy results indicated that the α-helix content decreased by 21.9 %, while β-sheets content increased by 45.0 % in 3.0 % PDF sample compared with the control (P < 0.05), and aliphatic residues cross-linked. Particle size, turbidity, and the roughness of MP surface morphology increased, whereas the zeta-potential of MPs decreased with PDF increasing. The gelation process of MP with PDF proceeded at a fast rate and their elasticity and viscosity were high as determined by dynamic rheology. Gels with 3.0 % PDF exhibited significantly enhanced gel strength and a high WHC, which increased by 44.20 % and 22.5 %, respectively, compared with the control, PDF inhibited the transformation of immobilized water to free water and eliminated the water channels during heating as well as formed a more uniform and denser microstructure. Therefore, PDF can be a potential ingredient for improving the quality of processed meat products.

Influence of repeated freeze-thaw treatments on the oxidation and degradation of muscle proteins from mirror carp (Cyprinus carpio L.), based on myofibrillar protein structural changes

The effects of repeated freeze-thaw (F-T) treatments on the oxidation and degradation of muscle proteins from mirror carp (Cyprinus carpio L.) were investigated. The myofibrillar fragmentation index, trichloroacetic acid-soluble peptides, total volatile basic nitrogen, amino nitrogen, and carbonyl content of the samples significantly increased (P < 0.05). However, the samples showed a significant reduction in the fragmentation index, myofibrillar protein (MP) solubility, and total sulfhydryl content after five F-T cycles (P < 0.05). Moreover, the sodium dodecyl sulfate-polyacrylamide gel electrophoresis bands of the MP faded because of the oxidation and degradation of the protein with increasing F-T cycles. By the fifth F-T cycle, the α-helix and β-turn content significantly decreased by 10.41 % and 5.72 %, respectively (P < 0.05), whereas the β-sheet and random coil content significantly rose by 7.66 % and 8.47 %, respectively (P < 0.05). Furthermore, the intrinsic fluorescence of the MP showed a substantial decrease in intensity and a redshift. In summary, iterative F-T cycles destroyed the MP structure and caused the oxidation and degradation of muscle proteins from mirror carp.

The positive contribution of ultrasound technology in muscle food key processing and its mechanism-a review

Traditional processing methods can no longer meet the demands of consumers for high-quality muscle food. As a green and non-thermal processing technology, ultrasound has the advantage of improving processing efficiency and reducing processing costs. Of these, the positive effect of power ultrasound in the processing of muscle foods is noticeable. Based on the action mechanism of ultrasound, the factors affecting the action of ultrasound are analyzed. On this basis, the effect of ultrasound technology on muscle food quality and its action mechanism and application status in processing operations (freezing-thawing, tenderization, marination, sterilization, drying, and extraction) is discussed. The transient and steady-state effects, mechanical effects, thermal effects, and chemical effects can have an impact on processing operations through complex correlations, such as improving the efficiency of mass and heat transfer. Ultrasound technology has been proven to be valuable in muscle food processing, but inappropriate ultrasound treatment can also have adverse effects on muscle foods. In the future, kinetic models are expected to be an effective tool for investigating the application effects of ultrasound in food processing. Additionally, the combination with other processing technologies can facilitate their intensive application on an industrial level to overcome the disadvantages of using ultrasound technology alone.

Structural Analysis and Study of Gel Properties of Thermally-Induced Soybean Isolate-Potato Protein Gel System

Heat-induced composite gel systems consisting of different soybean protein isolate (SPI) and potato protein (PP) mixtures were studied to elucidate their "backbone" and property changes. This was achieved by comparing the ratio of non-network proteins, protein subunit composition, and aggregation of different gel samples. It was revealed that SPI was the "gel network backbone" and PP played the role of "filler" in the SPI-PP composite gel system. Compared with the composite gels at the same ratio, springiness and WHC decrease with PP addition. For hardness, PP addition showed a less linear trend. At the SPI-PP = 2/1 composite gel, hardness was more than doubled, while springiness and WHC did not decrease too much and increased the inter-protein binding. The hydrophobic interactions and electrostatic interactions and hydrogen bonding of the SPI gel system were enhanced. The scanning electron microscopy results showed that the SPI-based gel system was able to form a more compact and compatible gel network. This study demonstrates the use of PP as a potential filler that can effectively improve the gelling properties of SPI, thus providing a theoretical basis for the study of functional plant protein foods.

Research Progress on the Preparation and Action Mechanism of Natural Deep Eutectic Solvents and Their Application in Food

Natural deep eutectic solvent (NADES) is the eutectic mixture which is formed by hydrogen bond donors (HBDs) and hydrogen bond acceptors (HBAs) with a certain molar ratio through hydrogen bonding. NADES is a liquid with low cost, easy preparation, biodegradability, sustainability and environmental friendliness at room temperature. At present, it is widely used in food, medicine and other areas. First, the composition, preparation and properties of NADES are outlined. Second, the potential mechanism of NADES in freezing preservation, the removal of heavy metals from food and the extraction of phenolic compounds, and its application in cryopreservation, food analysis and food component extraction, and as a food taste enhancer and food film, are summarized. Lastly, the potential and challenges of its application in the food field are reviewed. This review could provide a theoretical basis for the wide application of NADES in food processing and production.

On the emerging of thawing drip: Role of myofibrillar protein renaturation

This study aimed to facilitate the understanding on the origin of thawing drip under different freezing rate. Eventually we observed significantly greater thaw loss produced by slow freezing (8.58%) as compared to fast freezing (6.41%) after 24 h of thawing. Back to the freezing, ice crystallization induced decline in pH and the cold denaturation of myofibrillar protein. However, independent of freezing rate, we noticed protein renaturation with pH restoring during thawing, evidenced by the decreasing surface hydrophobicity, increasing solubility and thermal stability, and gradually stabilized secondary structure. Meanwhile, the water-holding of myofibrils increased with thawing process along with the rising water mobility. Under fast freezing, the results indicated less extensive protein cold denaturation and lower water mobility during thawing. Besides, we proposed that the microenvironment of lower ionic strength in fast freezing should benefit the protein renaturation and water re-absorption, ultimately contributed to lower thaw loss.

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.

Strategies to optimize the structural and functional properties of myofibrillar proteins: Physical and biochemical perspectives

Myofibrillar protein (MP), as the main meat protein, have high nutritional value. However, the relatively poor solubility of MP at low ionic strength sometimes limits the utilization of MP to produce products rich in meat protein. Accordingly, appropriate modification of MP is needed to improve their functional properties. In general, MP modification strategies are categorized into biochemical and physical approaches. Different from other available reviews, the review focuses on summarizing the principles and applications of several techniques of physical modification, briefly depicting biochemical modification as a comparison. Modification of MP with a certain intensity of direct current magnetic field, ultrasound, high pressure, microwave, or radio frequency can improve solubility, emulsification, stability, and gel formation. Of these, magnetic field and microwave-modified MP have shown some potential in reducing salt in meat. These physical techniques can also have synergistic effects with other conditions (temperature, pH, physical or chemical techniques) to compensate for the deficiencies of individual treatment techniques. However, these strategies still need further research for practical applications.HIGHLIGHTSThe current status and findings of research on direct current magnetic field in meat processing are presented.Several physical strategies to modify the microstructure and functional properties of MPs.The synergistic effects of these techniques in combination with other methods to modify MPs are discussed.

Role of low molecular additives in the myofibrillar protein gelation: underlying mechanisms and recent applications

Understanding mechanisms of myofibrillar protein gelation is important for development of gel-type muscle foods. The protein-protein interactions are largely responsible for the heat-induced gelation. Exogenous additives have been extensively applied to improve gelling properties of myofibrillar proteins. Research has been carried out to investigate effects of different additives on protein gelation, among which low molecular substances as one of the most abundant additives have been recently implicated in the modifications of intermolecular interactions. In this review, the processes of myosin dissociation under salt and the subsequent interaction via intermolecular forces are elaborated. The underlying mechanisms focusing on the role of low molecular additives in myofibrillar protein interactions during gelation particularly in relation to modifications of the intermolecular forces are comprehensively discussed, and six different additives i.e. metal ions, phosphates, amino acids, hydrolysates, phenols and edible oils are involved. The promoting effect of low molecular additives on protein interactions is highly attributed to the strengthened hydrophobic interactions providing explanations for improved gelation. Other intermolecular forces i.e. covalent bonds, ionic and hydrogen bonds could also be influenced depending on varieties of additives. This review can hopefully be used as a reference for the development of gel-type muscle foods in the future.

Effect and mechanism of functional compound fruit drink on gut microbiota in constipation mice

Compound fruit drink (CFD) is a functional drink prepared with fruit, Chinese herbs and prebiotic fructooligosaccharide as the main ingredients. Loperamide hydrochloride was used to establish a mouse model of constipation. And the effect of CFD on the improvement of constipation and the impact on gut microbiota were studied. The results showed that CFD significantly enhanced intestinal motility in constipated mice (P < 0.05). It significantly improved serum levels of gastrointestinal regulatory-related peptides, elevated the short-chain fatty acids (SCFAs) content and alleviated colonic injury. Meanwhile, CFD also up-regulated the mRNA expression levels of AQP3, AQP9, SCF and c-Kit and the related protein expression levels. Fecal microbial results showed that the CFD medium-dose group significantly increased species richness. Furthermore, CFD increased the abundance of potentially beneficial bacteria and reduced the number of potentially pathogenic bacteria. This study indicated that CFD was a promising functional drink for effectively relieving constipation.