Metabolism of hydrogen peroxide by Lactobacillus plantarum NJAU-01: A proteomics study.

This study aimed to investigate the time-course effect of Lactobacillus plantarum NJAU-01 in scavenging exogenous hydrogen peroxide (H2O2). The results showed that L. plantarum NJAU-01 at 107 CFU/mL was able to eliminate a maximum of 4 mM H2O2 within a prolonged lag phase and resume to proliferate during the following culture. Redox state in the start-lag phase (0 h, without the addition of H2O2), indicated by glutathione and protein sulfhydryl, was impaired in the lag phase (3 h and 12 h) and then gradually recovered during subsequent growing stages (20 h and 30 h). By using sodium dodecyl sulfate-polyacrylamide gel electrophoresis and proteomics analysis, a total of 163 proteins such as PhoP family transcriptional regulator, glutamine synthetase, peptide methionine sulfoxide reductase, thioredoxin reductase, ribosomal proteins, acetolactate synthase, ATP binding subunit ClpX, phosphoglycerate kinase, UvrABC system protein A and UvrABC system protein B were identified as differential proteins across the entire growth phase. Those proteins were mainly involved in H2O2 sensing, protein synthesis, repairing proteins and DNA lesions, amino sugar and nucleotide sugar metabolism. Our data suggest that biomolecules of L. plantarum NJAU-01 are oxidized to passively consume H2O2 and are restored by the enhanced protein and/or gene repair systems.

Myofibrillar protein composite gels: effect of esterified potato starch, lard and peanut oil on the gel properties.

BACKGROUND: Heat-induced composite gels were prepared with 20 g kg-1 myofibrillar protein (MP) sol, 20 g kg-1 modified starch and 100 g kg-1 lipid pre-emulsified by MP in 0.6 mol L-1 NaCl, at pH 6.2. The effects of esterified potato starch (EPS) and emulsified lipid (lard or peanut oil) on the rheology, texture properties and nuclear magnetic resonance characterization of MP gel were evaluated. RESULTS: The addition of starch and lipid significantly improved the gel strength and water holding capacity (WHC) of the MP gel. Analysis of the relaxation time compared with the WHC tests showed that the variation range of the transverse T22 relaxation time of a gel was positively proportional to changes in WHC of the composite gel, and the lower the T22 relaxation time, the better the WHC of composite gel. Moreover, MP gel with starch and emulsified lard added at the same time has the lowest T2 relaxation time, and also the best WHC of the gel. Environmental scanning electron microscopy showed that emulsified oil droplets embedded the gaps in the protein network, and the gelatinized starch contributed to restrict the oil droplet size, resulting in thicker MP gel. CONCLUSION: Emulsified lipid and modified starch have an important influence on the rheology and microstructure of MP gels, indicating the subtle interaction between starch, lipid and protein. The results suggest the potential feasibility of modified starch and vegetable oil to improve the textural properties in comminuted meat products. © 2021 Society of Chemical Industry.

Antioxidant activity of Lactobacillus plantarum NJAU-01 in an animal model of aging.

BACKGROUND: Excessive reactive oxygen species (ROS) can cause serious damage to the human body and may cause various chronic diseases. Studies have found that lactic acid bacteria (LAB) have antioxidant and anti-aging effects, and are important resources for the development of microbial antioxidants. This paper was to explore the potential role of an antioxidant strain, Lactobacillus plantarum NJAU-01 screened from traditional dry-cured meat product Jinhua Ham in regulating D-galactose-induced subacute senescence of mice. A total of 48 specific pathogen free Kun Ming mice (SPF KM mice) were randomly allocated into 6 groups: control group with sterile saline injection, aging group with subcutaneously injection of D-galactose, treatments groups with injection of D-galactose and intragastric administration of 107, 108, and 109 CFU/mL L. plantarum NJAU-01, and positive control group with injection of D-galactose and intragastric administration of 1 mg/mL Vitamin C. RESULTS: The results showed that the treatment group of L. plantarum NJAU-01 at 109 CFU/mL showed higher total antioxidant capacity (T-AOC) and the antioxidant enzymatic activities of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and catalase (CAT) than those of the other groups in serum, heart and liver. In contrast, the content of the oxidative stress marker malondialdehyde (MDA) showed lower levels than the other groups (P < 0.05). The antioxidant capacity was improved with the supplement of the increasing concentration of L. plantarum NJAU-01. CONCLUSIONS: Thus, this study demonstrates that L. plantarum NJAU-01 can alleviate oxidative stress by increasing the activities of enzymes involved in oxidation resistance and decreasing level of lipid oxidation in mice.

Effect of typical starch on the rheological properties and NMR characterization of myofibrillar protein gel.

BACKGROUND: Composite gels were individually prepared from 20 g kg-1 myofibrillar protein (MP) imbedded with typical native starch (potato, tapioca, rice or corn starch) in 0.6 mol L-1 NaCl at pH 6.2. The gel strength, water holding capacity, rheological properties and microstructure of the obtained myofibrillar protein-starch composite gels were evaluated. RESULTS: Tapioca starch improved (P < 0.05) gel strength and water holding capacity of MP composite gel at 80 °C. Rheological properties of MP-starch composites differed significantly with the addition of different types of native starch. Additionally, the promoting effect of starch on the storage modulus of the composite gels positively correlated with the gelatinization properties of different typical starch. Environmental scanning electron microscopy showed that the filling effect of starch on the composite gel was related to the pasting temperature and particle size of typical starch, with almost no particles forming at 80 °C. Moreover, the addition of starch changed the relaxation peak area and increased the relaxation time in nuclear magnetic resonance tests, which suggested that starch could improve the water holding capacity of MP-starch composite gels. CONCLUSION: Different typical native starch has varied impacts on the gel strength, water holding capacity, rheological properties and microstructure of MP gels, indicating the potential and feasibility of these typical native starches as an addition agent to modify the textural properties in comminuted meat products. © 2019 Society of Chemical Industry.

Rheology and microstructure of myofibrillar protein-olive oil composite gels: effect of different non-meat protein as emulsifier.

BACKGROUND: Heat-induced composite gels were prepared with 20 g kg-1 (2%) myofibrillar protein (MP) sol and 100 g kg-1 (10%) olive oil pre-emulsified by MP or non-meat protein in 0.6 mol L-1 NaCl, at pH 6.2. The effect of different non-meat protein (soy protein isolate, egg-white protein isolate and sodium caseinate) pre-emulsions on the rheological properties and microstructure of MP gel was evaluated. RESULTS: Adding emulsion enhanced the gel strength of MP gel except for the soy protein isolate (SPI) as emulsifier group, but all emulsion group markedly improved (P < 0.05) the water-holding capacity and the storage modulus (G') of MP gels. SDS-PAGE show that some non-meat protein bands partially participated in the formation of MP composite gels with different kinds of emulsion added. Micrographs revealed that these emulsions made the gels become denser and more compact with subtle diverse effects. CONCLUSION: Different meat or non-meat proteins as emulsifier have varied impacts on the rheology and microstructure of MP gels, indicating the potential and feasibility of these non-meat proteins as emulsifiers to modify the textural properties in comminuted meat products. © 2017 Society of Chemical Industry.

Antioxidant effect of apple phenolic on lipid peroxidation in Chinese-style sausage.

Chinese-style sausage is a very popular meat product obtained from a mixture of chopped pork meat, lard, salt, spices, additives (nitrate, nitrite, and antioxidants) and/or starter cultures. The antioxidative effect of apple phenolic on lipid oxidation in Chinese-style sausage compared with that of butylated hydroxy toluene (BHT) and ursolic acid were studied. Lipid oxidation was assessed through determination of thiobarbituric acid-reactive substances (TBARs) and volatile aldehydes. The content and composition of fatty acids in phospholipid were evaluated. At the optimum addition level, apple phenolic (0.5 g·kg(-1) in total fat) was more effective at inhibiting lipid oxidation than BHT (0.15 g·kg(-1) in total fat) and ursolic acid (0.5 g·kg(-1) in total fat) in Chinese-style sausages during 120 days storage. Moreover, apple phenolic exhibited stronger phospholipid protective capacity than ursolic acid and BHT at the end of storage. This study reveals a potential application of apple phenolic to enhance the oxidation stability of meat products during long storage.

Improving the solubility and interfacial absorption of hempseed protein via a novel high pressure homogenization-assisted pH-shift strategy.

A pH shift treatment aided by high pressure homogenization (HPH) with various pressures (0-120 MPa) was employed to structurally modify hempseed protein isolate (HPI). Compared with individual pH shift or HPH treatment, HPH-assisted pH shift improved the structural flexibility of HPI, as revealed by the increased random coil in protein secondary structure. With the incorporation of HPH into pH shift, the intrinsic fluorescence intensity was remarkably attenuated and redshifted, whereas the surface hydrophobicity was pronouncedly boosted, indicating the extensive unfolding of protein structure. Moreover, the cotreated HPI exhibited a smaller and more homogenous particle size, notably at a higher pressure. Consequently, the solubility was drastically raised by the cooperated treatments, to the maximum value (62.8 %) at 120 MPa. These physicochemical changes in the cotreated HPI facilitated a consolidated interfacial activity. Moreover, the cooperated treatment, especially highly pressured (120 MPa), facilitated the penetration and rearrangement of proteins at the oil-water interface.

Effects of ultrasound-assisted cooking on the physicochemical properties and microstructure of pork meatballs.

This research aims to investigate the effect of different ultrasonic powers cooking on the quality of pork meatballs. Pork meatballs treated with ultrasound-assisted cooking at 450 W had the most uniform and smooth structures displayed by scanning electron microscopy. Furthermore, with increasing ultrasonic powers, the water retention capacity of pork meatballs first increased and then decreased, compared with the non-ultrasound group, when the ultrasonic power was 450 W, the cooking yield of pork meatballs increased from 82.55% to 92.87%, and the centrifugal loss decreased from 25.35% to 11.52%. Additionally, ultrasound-assisted cooking had a positive effect on the moisture migration, tenderness, and sensory property of pork meatballs, and 450 W sample exhibited the highest overall acceptability score (P < 0.05). In conclusion, the physicochemical properties and microstructure of pork meatballs could be improved by appropriate ultrasonic power, and ultrasonic technology was considered as an effective processing method for improving the quality of meat products.

Inoculation fermentation with Lactobacillus fermentum L28 and Staphylococcus epidermidis S24 for improving the protein degradation of air-dried goose.

The inoculation fermentation technology was applied to the processing of dried cured goose to investigate the protein degradation. Lactobacillus fermentum (L), Staphylococcus epidermidis (S) and mixed strains (L + S) were individually inoculated into the whole goose before drying. We studied the degradation of protein in the air-dried period of goose. The results showed that compared with natural fermentation, inoculation fermentation significantly increased the content of non-protein nitrogen (14.85 mg/g NPN), proteolysis index (8.98% PI), myofibril fragmentation index (89.35 MFI) and total amount of free amino acids (1332.6 mg/g FAA) of dried cured goose. Electrophoresis revealed that the inoculation fermentation accelerated the degradation of macromolecular proteins and the accumulation of small molecular proteins. The degree of protein degradation in four groups of goose was in an order of L + S group > S group > L group > CK group. It suggested that inoculation fermentation could promote the degradation of myofibrillar proteins.

The ameliorative mechanism of Lactiplantibacillus plantarum NJAU-01 against D-galactose induced oxidative stress: a hepatic proteomics and gut microbiota analysis.

Probiotic intervention is an effective strategy to alleviate oxidative stress-related diseases. Our previous studies found that Lactiplantibacillus plantarum NJAU-01 (NJAU-01) exhibited antioxidant effects in a D-galactose (D-gal)-induced aging mouse model. However, the underlying mechanism remains to be unveiled. This study was aimed to investigate the ameliorative effect and mechanism of NJAU-01 against oxidative stress induced by D-gal. The results showed that NJAU-01 could reverse the tendency of a slow body weight gain induced by D-gal. NJAU-01 relieved hepatic oxidative stress via increasing the hepatic total antioxidant capacity and antioxidant enzyme activities including superoxide dismutase (SOD), glutathione peroxidase (GSH-Px) and catalase (CAT). Moreover, the malondialdehyde (MDA) level was reversed after NJAU-01 supplementation. The proteomic results showed that there were 201 differentially expressed proteins (DEPs) between NJAU-01 and D-gal groups. NJAU-01 regulated the expressions of glutathione S-transferase Mu 5 (Gstm5), glutathione S-transferase P2 (Gstp2) and NADH dehydrogenase 1α subcomplex subunit 7 (Ndufa7) related to oxidative stress, and autophagy protein 5 (Atg5) and plasma alpha-L-fucosidase (Fuca2) involved in autophagy, etc. 16S rDNA sequencing results showed that NJAU-01 supplementation could regulate the gut microbiota dysbiosis induced by D-gal via increasing the relative abundances of the phylum Firmicutes and the genus Lactobacillus and reducing the relative abundances of the phylum Bacteroidetes and the genera Lachnospiraceae_NK4A136_group as well as Prevotellaceae_UCG-001, etc.. Spearman correlation analysis results showed that the altered gut microbiota composition had a significant correlation with antioxidant enzyme activities and the DEPs related to oxidative stress. Overall, NJAU-01 alleviated hepatic oxidative stress induced by D-gal via manipulating the gut microbiota composition and hepatic protein expression profile.

Oxidative Modification, Structural Conformation, and Gel Properties of Pork Paste Protein Mediated by Oxygen Concentration in Modified Atmosphere Packaging.

The objective of this study was to investigate the effect of pork oxidation through modified atmosphere packaging (MAP) on gel characteristics of myofibrillar proteins (MP) during the heat-induced gelation process. The pork longissimus thoracis (LT) was treated by MAP at varying oxygen concentrations (0, 20, 40, 60, and 80% O2) with a 5-day storage at 4 °C for the detection of MP oxidation and gel properties. The findings showed the rise of O2 concentration resulted in a significant increase of carbonyl content, disulfide bond, and particle size, and a decrease of sulfhydryl content and MP solubility (p < 0.05). The gel textural properties and water retention ability were significantly improved in MAP treatments of 0-60% O2 (p < 0.05), but deteriorated at 80% O2 level. As the concentration of O2 increased, there was a marked decrease in the α-helix content within the gel, accompanied by a simultaneous increase in ß-sheet content (p < 0.05). Additionally, a judicious oxidation treatment (60% O2 in MAP) proved beneficial for crafting dense and uniform gel networks. Our data suggest that the oxidation treatment of pork mediated by O2 concentration in MAP is capable of reinforcing protein hydrophobic interaction and disulfide bond formation, thus contributing to the construction of superior gel structures and properties.

Enhanced gelling properties of myofibrillar protein by ultrasound-assisted thermal-induced gelation process: Give an insight into the mechanism.

Effects of the incorporation of ultrasound with varied intensities (0-800 W) into the thermal-induced gelation process on the gelling properties of myofibrillar protein (MP) were explored. In comparison with single heating, ultrasound-assisted heating (<600 W) led to significant increases in gel strength (up to 17.9%) and water holding capacity (up to 32.7%). Moreover, moderate ultrasound treatment was conducive to the fabrication of compact and homogenous gel networks with small pores, which could effectively impair the fluidity of water and allow redundant water to be entrapped within the gel network. Electrophoresis revealed that the incorporation of ultrasound into the gelation process facilitated more proteins to get involved in the development of gel network. With the intensified ultrasound power, α-helix in the gels lowered pronouncedly with a simultaneous increment of ß-sheet, ß-turn, and random coil. Furthermore, hydrophobic interactions and disulfide bonds were reinforced by the ultrasound treatment, which was in support of the construction of preeminent MP gels.

Effects of Transglutaminase on Myofibrillar Protein Composite Gels with Addition of Non-Meat Protein Emulsion.

The emulsions prepared by three non-meat proteins, sodium caseinate (SC), soy protein isolate (SPI) and egg white protein (EPI), were individually added to the continuous phase of myofibrillar protein (MP) sol to form MP composite gels to simulate meat products. The research aimed to investigate the effects of Transglutaminase (TGase) on the physicochemical properties, microstructure and water phase distribution of non-meat protein emulsion MP composite gels. The results of this study revealed that TGase played a crucial role in forming a tight gel network structure in the composite gels. This enhanced their ability to retain water and improved their overall gel strength. Additionally, TGase increased the gel formation temperature of myofibrillar proteins. Electrophoresis analysis showed that when catalyzed by TGase, there was a lighter band compared to those not catalyzed by TGase. This indicated that the addition of TGase facilitated cross-linking interactions between meat proteins and non-meat proteins in the composite gels. Furthermore, microscopy observations demonstrated that composite gels treated with TGase exhibited a more uniform microstructure. This could be attributed to an acceleration in relaxation time T2. The uniform network structure restricted the movement of water molecules in the gel matrix, thereby improving its water-holding capacity. Overall, these findings highlight how incorporating non-meat proteins into myofibrillar systems can be effectively achieved through enzymatic treatment with TGase. Such modifications not only enhanced important functional properties but also contributed towards developing alternative meat products with improved texture and moisture retention abilities.

Arabic gum grafted with phenolic acid as a novel functional stabilizer for improving the oxidation stability of oil-in-water emulsion.

Three kinds of phenolic acids: ferulic acid (FA), caffeic acid (CA), and gallic acid (GA) with different chemical structures were individually grafted onto Arabic gum (AG) via a laccase mediated method, and their roles in stabilizing o/w emulsions were evaluated. The total phenolic content in modified AG increased from 2.7 ± 0.2 to 18.7 ± 0.2, 19.8 ± 0.6, 22.4 ± 0.8 mg/g after 4 h of laccase catalysis, respectively. FTIR spectra of modified AGs exhibited additional phenolic characteristics, revealing the successful grafting of phenolic acids to AG structure. Compared with natural AG, modified AGs showed remarkably enhanced thermal stability, as well as antioxidant capacity in an order of gallic acid > caffeic acid > ferulic acid. The incorporation of phenolic acids into AG dramatically improved its emulsification performance. Herein, gallic acid-modified AG evinced up to 17.6 % and 12.6 % increments in emulsifying activity and emulsion stability relative to natural AG, respectively. Moreover, the oxidative stability of AG emulsions was pronouncedly meliorated by the introduced phenolic acids, especially gallic acid, as manifested by the suppressed production of primary and secondary oxidation products.

Exploring the role of protein DJ-1 in quality of pale, soft and exudative (PSE) and red, firm and non-exudative (RFN) pork during post-mortem aging.

The purpose of this study was to investigate the changes of oxidative attributes, protein DJ-1 expression, oxidized form (oxDJ-1), and cellular localization in RFN and PSE pork meat during the post-mortem aging. The longissimus thoracis of RFN and PSE groups were collected and classified by determination of pH, color and purge loss and then aged for 1, 3 and 7 d at 4 °C postmortem. Results showed that the content of DJ-1 and oxDJ-1 was continuously increased during 7 d of postmortem aging. A relatively higher protein DJ-1, oxDJ-1, oxygen reactive species and disulfide bond contents were found in PSE meat in comparison to RFN meat. Immunostaining showed that protein DJ-1 was located in cytoplasm, membrane and some nucleus of muscle cells. DJ-1 was shown to correlate with meat quality and oxidative attributes, suggesting a regulatory role in resisting oxidative stress and meat quality formation during post-mortem aging.

Effects of octenyl succinylation on the properties of starches with distinct crystalline types and their Pickering emulsions.

Effects of octenylsuccinic anhydride (OSA) esterification on the morphology, crystalline structure, and emulsifying properties of three representative starches with different crystalline types, namely waxy corn starch (A-type), potato starch (B-type), and pea starch (C-type) were investigated. XRD patterns testified OSA substitution occurred principally in the amorphous region without affecting the crystalline patterns, whereas SEM verified esterification was mainly a surface phenomenon. However, OSA esterification caused a decrease in the peak intensity and area of small-angle X-ray scattering profiles, indicating the semi-crystalline lamellae ordering was impeded to a certain extent. Compared with A- and C-type starches, B-type starch had a stronger affinity for OSA, as manifested by its higher degree of substitution (DS), graver surface detriment, and depressed order of semi-crystalline lamellae. The emulsifying properties of all starches were pronouncedly improved by OSA modification, especially for A-type starch even with comparatively lower DS. Pickering emulsion stabilized by OSA-modified A-type starch (A-OSAS) with smaller droplet size and more uniform droplet size distribution exhibited more splendiferous stability relative to the other two modified starches. Moreover, rheological tests revealed A-OSAS possessed the highest apparent viscosity and storage modulus (G'), insinuating strong intermolecular interactions between starch granules at the interface and/or in the continuous phase.

Quantitative proteomics analysis on the meat quality of processed pale, soft, and exudative (PSE)-like broiler pectoralis major by different heating methods.

This study aims to assess and compare the influences of different heating methods on the quality characteristics of pale, soft, and exudative (PSE)-like and normal (NOR) pectoralis major through quantitative proteomic analysis. A total of 632 proteins were identified, and there were 84, 89, 50, and 43 differentially abundant proteins (DAPs) between processed PSE and NOR samples after four thermal treatments, including boiling (BO), steaming (ST), roasting (RO), and microwaving (MV), respectively, where moist heating conditions led to more different protein abundance. Processed PSE muscles resulted in significant changes in structural proteins related to myofibrillar and connective tissue, which could be associated with their structural instability and degraded quality. Collagen, tropomyosin, myoglobin, and hemoglobin could be potential indicators of PSE muscles color stability and variation during thermal processing. The quantitative proteomic analysis will help correlate molecular changes with processed meat quality towards future optimization of PSE poultry meat processing.

Consolidating the gelling performance of myofibrillar protein using a novel OSA-modified-starch-stabilized Pickering emulsion filler: Effect of starches with distinct crystalline types.

Starch-stabilized Pickering emulsions were employed as a novel particulate filler in myofibrillar protein (MP)-based gels for improving the gelling characteristics. The role of emulsions prepared by native starches (NS) with distinctive crystalline types (i.e., A-type waxy corn starch, B-type potato starch, and C-type pea starch) and their OSA-modified counterparts (A-OS, B-OS, C-OS) in the gelling performance was evaluated and compared with MP-stabilized-emulsion. Compared with MP-emulsion, starch-emulsion caused substantial increases in the gelling properties, notably for OSA-starch emulsions. Herein, A-OS exhibited up to 1.26-, 5.3-, and 2.9-fold increments in storage modulus, gel strength, and water holding capacity relative to pure MP gel, respectively, higher than B-OS and C-OS. Moreover, light microscopy evinced a more compact gel network filled with smaller and uniform oil droplets when A-OS emulsions were incorporated into the gels. The addition of OSA-starch emulsions, especially A-OS emulsion, facilitated the protein conformational conversion from α-helix to ß-sheet and caused a marked reduction of free sulfhydryls in the gels; yet, the chemical forces that stabilized the gels altered, where remarkable reinforcements in hydrogen bond and hydrophobic interaction were detected, in support of the construction of splendid MP gels. Hence, OSA-starch emulsions show promise as functional components in meat products.

Effects of the addition of leucine on flavor and quality of sausage fermented by Lactobacillus fermentum YZU-06 and Staphylococcus saprophyticus CGMCC 3475.

Methyl-branched aldehydes, especially 3-methylbutanal, have been reported to be perceived either as a malty or as a nutty/chocolate-like aroma and were considered an important flavor contributor in fermented meat products. Decomposition of leucine (Leu) by branched-chain amino acid transaminase (BACT) is a crucial step in the metabolism of Leu to 3-methylbutanal. This study was conducted to explore the effects of mixed-starter culture (Lactobacillus fermentum YZU-06 and Staphylococcus saprophyticus CGMCC 3475) and addition of Leu (0, 1, and 3 mM) on the flavor and quality of fermented sausages. The pH, water activity, texture profile analysis, color, counts of lactic acid bacteria (LAB) and staphylococci, peptide, and flavor compounds were detected during fermentation. The results showed that the starter culture group increased hardness, elasticity, the counts of LAB and staphylococci, peptide content, volatile flavor compounds, as well as the sensorial scores of sausage, while decreasing pH, a w , and L* and b* values compared with the non-inoculation group. The mixed starter of adding with 3 mM Leu enhanced the content of 3-methylbutanal and overall flavor of fermented sausages. It is applicable to directionally produce methyl-branched aldehydes and improve the overall quality of fermented sausage by the addition of Leu and using starter of L. fermentum YZU-06 and S. saprophyticus CGMCC 3475.

A comparative study of vacuum tumbling and immersion marination on quality, microstructure, and protein changes of Xueshan chicken.

Marination is a common technology in meat processing with advantages of enhancing tenderness, water retention, and overall quality. This study was conducted to investigate the effect of vacuum tumbling and immersion marination on meat quality, microstructure, water mobility, protein changes, and denaturation of Xueshan chicken. Results showed that vacuum tumbling significantly increased the marinating rate of chicken, tenderness, meat texture, and water retention. Meanwhile, vacuum tumbling decreased total sulfhydryl content alongside an increased protein surface hydrophobicity and free sulfhydryl content, indicating that vacuum tumbling elevated the degree of protein denaturation. Further, the peak area corresponding to the relaxation time T22 after vacuum tumbling was significantly higher than that of immersion marination, suggesting that the stability of the immobilized water of chicken was reduced by vacuum tumbling. Compared to immersion marination, vacuum tumbling improved myofibril fragmentation index (MFI) presenting fewer myofibrillar protein bands in sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) gel and more damaged muscular cells. Overall, vacuum tumbling could improve the marination absorptivity, protein degradation, and denaturation, resulting in changes in myofibril structure and meat quality of Xueshan chicken.