Effects of Drying Methods on the Physicochemical and Functional Properties of Cinnamomum camphora Seed Kernel Protein Isolate.

Cinnamomum camphora seed kernel protein isolate (CPI) has attracted increasing attention due to its sustainability and potential applications. This study aimed to investigate the effects of freeze-drying (FD), vacuum-drying (VD), and spray-drying (SD) on the physicochemical and functional properties of CPI. The morphology observation results showed that the SD-CPI, SD-CPI, and VD-CPI were spherical, lamellar, and massive, respectively. Compared to FD and SD, VD had more impact on the color, surface hydrophobicity, intermolecular disulfide bonds, intrinsic fluorescence, and thermal stability of CPI. Fourier transform infrared spectroscopy (FTIR) analyses showed that among three CPI samples, VD-CPI had the highest content of ß-sheet but the lowest contents of α-helix and ß-turn. At different pH values, the solubility, emulsification, and foaming properties of VD-CPI were inferior to those of FD-CPI and SD-CPI. These results provide useful information on the changes in the physicochemical and functional properties of CPI subjected to different drying methods, and offer theoretical guidance for the production and use of CPI in the food industry.

Production, purification, properties and current perspectives for modification and application of microbial lipases.

With the industrialization and development of modern science, the application of enzymes as green and environmentally friendly biocatalysts in industry has been increased widely. Among them, lipase (EC. 3.1.1.3) is a very prominent biocatalyst, which has the ability to catalyze the hydrolysis and synthesis of ester compounds. Many lipases have been isolated from various sources, such as animals, plants and microorganisms, among which microbial lipase is the enzyme with the most diverse enzymatic properties and great industrial application potential. It therefore has promising applications in many industries, such as food and beverages, waste treatment, biofuels, leather, textiles, detergent formulations, ester synthesis, pharmaceuticals and medicine. Although many microbial lipases have been isolated and characterized, only some of them have been commercially exploited. In order to cope with the growing industrial demands and overcome these shortcomings to replace traditional chemical catalysts, the preparation of new lipases with thermal/acid-base stability, regioselectivity, organic solvent tolerance, high activity and yield, and reusability through excavation and modification has become a hot research topic.

Effect of Different Medium-Chain Triglycerides on Glucose Metabolism in High-Fat-Diet Induced Obese Rats.

Obesity can be associated with significant metabolic disorders. Our previous study found that medium-chain triglycerides (MCTs) improved lipid metabolism in obese rats. However, scant attention has been given to exploring the impact of MCTs on glucose metabolism in obese rats. This study is designed to examine the effects and mechanisms of three distinct MCTs on glucose metabolism in obese rats. To induce obesity, Sprague-Dawley (SD) rats were fed a high-fat diet, followed by a 12-week treatment with caprylic triglyceride (CYT), capric triglyceride (CT), and lauric triglyceride (LT). The results showed that three types of MCT intervention reduced the levels of lipids (TC, TG, LDL-c, and HDL-c), hyperglycemia, insulin resistance (insulin, OGTT, HOMA-IR, and ISI), and inflammatory markers (IL-4, IL-1ß, and TNF-α) in obese rats (p < 0.01), The above parameters have been minimally improved in the high-fat restoring group (HR) group. MCTs can modulate the PI3K/AKT signaling pathways to alleviate insulin resistance and improve glucose metabolism in obese rats. Furthermore, MCTs can activate peroxisome proliferator-activated receptor (PPAR) γ and reduce the phosphorylation of PPARγser237 mediated by CDK5, which can improve insulin sensitivity without lipid deposition in obese rats. Among the MCT group, CT administration performed the best in the above pathways, with the lowest blood glucose level and insulin resistance. These findings contribute to a deeper understanding of the connection between health benefits and the specific type of MCT employed.

Characterization of selected phages for biocontrol of food-spoilage pseudomonads.

Pseudomonas spp., such as P. fluorescens group, P. fragi, and P. putida, are the major psychrophilic spoilage bacteria in the food industry. Bacteriophages (phages) are a promising tool for controlling food-spoilage and food-poisoning bacteria; however, there are few reports on phages effective on food-spoilage bacteria such as Pseudomonas spp. In this study, 12 Pseudomonas phages were isolated from chicken and soil samples. Based on the host range and lytic activity at 30 °C and 4 °C and various combinations of phages, phages vB_PflP-PCS4 and vB_PflP-PCW2 were selected to prepare phage cocktails to control Pseudomonas spp. The phage cocktail consisting of vB_PflP-PCS4 and vB_PflP-PCW2 showed the strongest lytic activity and retarded regrowth of P. fluorescens and P. putida at 30 °C, 8 °C, and 4 °C at a multiplicity of infection of 100. Nucleotide sequence analysis of the genomic DNA indicated that vB_PflP-PCS4 and vB_PflP-PCW2 phages were lytic phages of the Podoviridae family and lacked tRNA, toxin, or virulence genes. A novel endolysin gene was found in the genomic DNA of phage vB_PflP-PCS4. The results of this study suggest that the phage cocktail consisting of vB_PflP-PCS4 and vB_PflP-PCW2 is a promising tool for the biocontrol of psychrophilic food-spoilage pseudomonads during cold storage and distribution.

Isolation, characterization of Enterococcus phages and their application in control of E. faecalis in milk.

AIMS: Isolation and characterization of Enterococcus phages and application of phage cocktail to control E. faecalis in milk. METHODS AND RESULTS: For phage isolations, double layer agar method was used. Host range of the phages were determined by the spot test. Twelve phages with varying host ranges were isolated. Phages PEF1, PEF7b, and PEF9 with different host ranges and lytic activities were selected for phage cocktails. Compared to two-phages cocktails tested, the cocktail containing all the three phages displayed stronger antibacterial and biofilm removal activities. The cocktail treatment reduced viable E. faecalis in biofilm by 6 log within 6 h at both 30°C and 4°C. In milk, the cocktail gradually reduced the viable count of E. faecalis and the count reached below the lower limit of detection at 48 h at 4°C. CONCLUSION: The strong bactericidal and biofilm removal activities of the phage cocktail suggest the potential of this cocktail as a natural biocontrol agent for combating E. faecalis in milk.

Potential application of phage vB_EfKS5 to control Enterococcus faecalis and its biofilm in food.

Contaminated food with antibiotic-resistant Enterococcus spp. could be the vehicle for transmitting Enterococcus to humans and accordingly cause a public health problem. The accumulation of biogenic amines produced by Enterococcus faecalis (E. faecalis) in food may have cytological effects. Bacteriophages (phage in short) are natural antimicrobial agents and can be used alone or in combination with other food preservatives to reduce food microbial contaminants. The aim of this study was to isolate a novel phage against E. faecalis and determine its host range to evaluate its potential application. Bacteriophage, vB_EfKS5, with a broad host range, was isolated to control the growth of E. faecalis. The vB_EfKS5 genome is 59,246 bp in length and has a GC content of 39.7%. The computational analysis of phage vB_EfKS5 genome confirmed that it does not contain any lysogenic, toxic, or virulent genes. Phage vB_EfKS5 exhibited lytic activity against most E. faecalis isolates with different multiplicities of infections and it infected 75.5% (22/29) of E. faecalis isolates and 42.3% (3/7) of E. faecium isolates. It was also able to destroy the biofilm formed by E. faecalis with different MOIs. Phage vB_EfKS5 alone or in combination with nisin could control the growth of E. faecalis in broth and milk. Based on its high productivity, stability, short latent period, and large burst size, phage vB_EfKS5 has a high potential for applications both in food and medical applications.

Comparison of prevalence, characterization, antimicrobial resistance and pathogenicity of foodborne Listeria monocytogenes in recent 5 years in Japan.

This study investigated the prevalence, serotype, antimicrobial resistance (AMR), virulence potential, and biofilm formation of Listeria monocytogenes isolated in 2022 in Japan and compared their profiles with those of isolates in 2012 and 2017. A total of 85 chicken samples were randomly collected from different supermarkets in Fukuoka in 2022. L. monocytogenes were isolated by conventional method and characterized by MALDI-TOF MS. Among 85 samples tested in 2022, 9 (10.6%) were positive for L. monocytogenes and 17 strains were isolated from the positive samples. The isolates were serotyped as 1/2b (41.2%), 3a (29.4%), 3b (23.5%) and 1/2a (5.9%). Antimicrobial susceptibility tests of the 2022 isolates showed susceptibility to majority of the antibiotics, except cefoxitin, oxacillin, and fosfomycin. Compared to the previous surveillance results, the prevalence of L. monocytogenes in 2022 (10.6%) was significantly lower (p < 0.05) than those of the isolates in 2017 (24%) and 2012 (52.9%). The distribution of serotypes 1/2a and 1/2b decreased over time, and serotype 4b was not detected in the 2022 isolates. The proportion of multidrug resistant strains in 2022 (16.7%) was significantly lower than those in 2012 (46.7%) and 2017 (82.6%). Moreover, a total of 36 isolates (12 isolates/ year) were used to detect the virulence genes (hlyA, plcA, clpC, and inlA) and biofilm-forming capacity. Most of the isolates from different years harboured four virulence genes. The biofilm formation of the 2022 isolates was significantly weaker (p < 0.05) than those of the 2012 and 2017 isolates. Thus, despite the low rates of contamination in chicken meat and AMR of the isolates, virulent L. monocytogenes contamination in food should still be acknowledged.

Geographic Pattern of Variations in Chemical Composition and Nutritional Value of Cinnamomum camphora Seed Kernels from China.

Cinnamomum camphora (camphor tree) is an important non-conventional edible plant species found in East Asia. Here, a detailed characterization for the chemical composition and nutritional value of C. camphora seed kernels (CCSKs) collected from different regions in China is provided. The results showed that there were significant differences among the CCSK samples in weights (1000 fruits, 1000 seeds and 1000 kernels), proximate composition, minerals, phenolics, flavonoids and amino acid contents. The highest contents of oil (62.08%) and protein (22.17%) were found in the CCSK samples collected from Chongqing and Shanghai, respectively. The highest content of mineral in the CCSK samples was K (4345.05-7186.89 mg/kg), followed by P (2735.86-5385.36 mg/kg), Ca (1412.27-3327.37 mg/kg) and Mg (2028.65-3147.32 mg/kg). The CCSK sample collected from Guizhou had the highest levels of total phenolic and flavonoid contents (TPC and TFC), while that from Chongqing had the lowest levels. In addition, the most abundant fatty acid in the CCSK samples was capric acid (57.37-60.18%), followed by lauric acid (35.23-38.29%). Similarities in the fatty acid composition among the CCSK samples were found. The CCSK sample collected from Guizhou had the highest percentage (36.20%) of essential amino acids to total amino acids, and Chongqing had the lowest value (28.84%). These results indicated that CCSK may be developed as an excellent source of plant-based medium-chain oil, protein, dietary fiber, minerals, phytochemicals and essential amino acids.

Biocontrol of Salmonella Typhimurium in milk, lettuce, raw pork meat and ready-to-eat steamed-chicken breast by using a novel bacteriophage with broad host range.

Salmonella spp., one of the most frequently reported bacteria, causes foodborne illness and economic losses. Due to the threat of increasing antibiotic resistant foodborne pathogens, application of bacteriophages as novel antibacterial agents in food matrices has become an emerging strategy. In this study, a novel Salmonella phage PS3-1 with high lytic activity against Salmonella Typhimurium was identified from previously isolated phages. PS3-1 belonged to the class Caudoviricetes with a broad host range, and had relatively short latent period (15 min), large burst size (92 PFU/cell), high pH stability (pH 3.0-11.0) and thermal tolerance (4-60 °C). Genome sequencing analysis showed that PS3-1 genome consisted of 107,110 bp DNA, without antibiotic resistance and virulence related genes. The results of growth curve and time-kill assay showed that PS3-1 not only inhibited the growth of S. Typhimurium, but also effectively decreased the viable cell counts (0.30-4.72 log) after 24-h incubation at 7, 25 and 37 °C (P < 0.05). Moreover, >1.28 log of established biofilm cells were effectively removed after 24-h treatment with PS3-1. Besides, PS3-1 significantly reduced the viability of S. Typhimurium in milk, lettuce, raw pork meat and ready-to-eat steamed-chicken breast at different temperatures (P < 0.05). These results demonstrated that PS3-1 may be an excellent antibacterial agent for controlling S. Typhimurium in food industry.

Restricted Phase Space Thermodynamics of Einstein-Power-Yang-Mills AdS Black Hole.

We consider the thermodynamics of the Einstein-power-Yang-Mills AdS black holes in the context of the gauge-gravity duality. Under this framework, Newton's gravitational constant and the cosmological constant are varied in the system. We rewrite the thermodynamic first law in a more extended form containing both the pressure and the central charge of the dual conformal field theory, i.e., the restricted phase transition formula. A novel phenomena arises: the dual quantity of pressure is the effective volume, not the geometric one. That leads to a new behavior of the Van de Waals-like phase transition for this system with the fixed central charge: the supercritical phase transition. From the Ehrenfest's scheme perspective, we check out the second-order phase transition of the EPYM AdS black hole. Furthermore the effect of the non-linear Yang-Mills parameter on these thermodynamic properties is also investigated.

Dextran Conjugation Improves the Structural and Functional Properties of Heat-Treated Protein Isolate from Cinnamomum camphora Seed Kernel.

The Cinnamomum camphora seed kernel (CCSK), with high contents of medium-chain oil (~59%) and protein (~19%), is an excellent source for a plant-based food ingredient. To broaden the application of the protein isolate (PI) from CCSK in the food industry, the Maillard reaction products (MRPs) were prepared by PI and dextran (DX) under mild wet-heating conditions (60 °C, 5 h), and the structural and functional properties of the PI-DX conjugates were investigated. The covalent bond between PI and DX was confirmed by the degree of grafting and sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Compared with the heated PI, the PI-DX conjugates had more ordered structure, with the decreased random coil content. The changes in tertiary structure of PI-DX conjugates were reflected by the results of intrinsic fluorescence and surface hydrophobicity. Moreover, PI-DX conjugates showed better solubility, emulsifying properties, thermal stability and antioxidant activities. These results provided a theoretical basis for the development of PI-based MRPs with desirable characteristics.

A common whole-genome paleotetraploidization in Cucurbitales.

Cucurbitales are an important order of flowering plants known for encompassing edible plants of economic and medicinal value and numerous ornamental plants of horticultural value. By reanalyzing the genomes of two representative families (Cucurbitaceae and Begoniaceae) in Cucurbitales, we found that the previously identified Cucurbitaceae common paleotetraploidization that occurred shortly after the core-eudicot-common hexaploidization event is shared by Cucurbitales, including Begoniaceae. We built a multigenome alignment framework for Cucurbitales by identifying orthologs and paralogs and systematically redating key evolutionary events in Cucurbitales. Notably, characterizing the gene retention levels and genomic fractionation patterns between subgenomes generated from different polyploidizations in Cucurbitales suggested the autopolyploid nature of the Begoniaceae common tetraploidization and the allopolyploid nature of the Cucurbitales common tetraploidization and the Cucurbita-specific tetraploidization. Moreover, we constructed the ancestral Cucurbitales karyotype comprising 17 proto-chromosomes, confirming that the most recent common ancestor of Cucurbitaceae contained 15 proto-chromosomes and rejecting the previous hypothesis for an ancestral Cucurbitaceae karyotype with 12 proto-chromosomes. In addition, we found that the polyploidization and tandem duplication events promoted the expansion of gene families involved in the cucurbitacin biosynthesis pathway; however, gene loss and chromosomal rearrangements likely limited the expansion of these gene families.

Effects of medium chain triglycerides on lipid metabolism in high-fat diet induced obese rats.

This study aimed to compare the effects of three different medium chain triglycerides (MCTs) on lipid metabolism in obese rats. A high fat diet was fed to Sprague-Dawley rats to induce obesity, and then caprylic triglyceride (CYT), capric triglyceride (CT) and lauric triglyceride (LT) were synthesized and used to treat the obese rats for 12 weeks. The obesity phenotype and molecular changes related to lipid metabolism were determined. The results showed that all the three MCTs reduced the body weight (BW) and fat coefficient in obese rats, and the levels of plasma and liver lipids were also improved. Among the MCT groups, the LT group showed the lowest BW with the lowest food intake. Furthermore, three MCTs had different effects on the expression levels of lipid metabolism-related proteins (PPARs and SREBPs). The LT group performed the best among the three MCT groups in the protein expression levels. Interestingly, high-dose LT decreased the expression of the low density lipoprotein receptor (LDLR) in the liver, which impaired the transport of the very low density lipoprotein (VLDL)/low density lipoprotein (LDL) to the liver, resulting in high levels of total plasma cholesterol (TC) and LDL-c in the rats. We have for the first time found that different MCTs had different effects on the expression levels of triacylglycerol and cholesterol metabolism-related proteins in obese rats. These findings would help better understand the relationship between the health benefit and the type of MCT.

Medium-chain triglycerides improve lipid metabolism in obese rats through increasing the browning of adipose tissue via sympathetic regulation.

This study aimed to determine the effect and mechanism of medium-chain triglycerides (MCTs) on promoting the browning of adipose tissue. A high-fat diet was fed to the Sprague-Dawley rats to induce obesity, then caprylic triglycerides (CYTs), capric triglycerides (CTs) and lauric triglycerides (LTs) were used to treat the obese rats for 12 weeks. The obesity phenotype and molecular changes related to browning were determined. The results showed that all three MCTs promoted the browning/beiging of the adipose tissues (brown and white adipose tissue), and lipolysis in these tissues was also increased, which ameliorated high-fat diet-induced lipid metabolic disorders in the obese rats. The LT group showed the highest expression levels of lipolysis- and browning/beiging-related proteins, followed by the CT group and CYT group. We speculate that the browning process may be related to sympathetic regulation and all the three MCT administration increased the secretion of neurotrophic factors both in the hypothalamus and adipose tissue. Then, intra-adipose sympathetic arborization increased, resulting in the activation of the sympathetic regulatory system in MCT groups, and the LT group also showed the highest sympathetic nerve fiber density, followed by the CT group and CYT group. We have for the first time found that the effect of medium-chain fatty acids on adipose tissue browning might be related to the types of fatty acids.

Effects of preheat treatment and polyphenol grafting on the structural, emulsifying and rheological properties of protein isolate from Cinnamomum camphora seed kernel.

In this study, protein isolate (PI) and purified polyphenol extract (PPE) were prepared from Cinnamomum camphora seed kernel (CCSK). The effects of preheat treatment (50-90 °C) combined with polyphenol grafting (5 % PPE, w/w) on the structural, emulsifying and rheological properties of PI were investigated. Results demonstrated the preheat treatments at 80 and 90 °C significantly increased the extent of protein aggregation of PI. Fluorescence spectra and thermal behavior analysis revealed that preheat-treated PI exhibited more compact structure and higher thermal stability. Moreover, the emulsifying stability and apparent viscosity of PI were enhanced after preheat treatments at 50, 60 and 70 °C. After modification by PPE, the secondary structural changes of preheat-treated PI were confirmed by FTIR. PPE modification improved the thermal stability and antioxidant activities of preheat-treated PI. These results provide a novel way to combine the advantages of preheat treatment and polyphenol grafting in developing a novel protein ingredient.

Green synthesis of polydopamine functionalized magnetic mesoporous biochar for lipase immobilization and its application in interesterification for novel structured lipids production.

In this study, the polydopamine functionalized magnetic mesoporous biochar (MPCB-DA) was prepared for immobilization of Bacillus licheniformis lipase via covalent immobilization. Under optimized immobilization conditions, the maximum immobilization yield, efficiency and immobilized lipase amount were found to be 45%, 54% and 36.9 mg/g, respectively. The immobilized lipase, MPCB-DA-Lipase showed good thermal stability and alkali resistance. The MPCB-DA-Lipase retained 56% initial activity after 10 reuse cycles, with more than 85% relative activity after 70 days' storage at 4 or 25 °C. The MPCB-DA-Lipase was efficiently applied in the interesterification of Cinnamomum camphora seed kernel oil and perilla seed oil, with maximum interesterification efficiency of 46%. The produced structured lipids belong to the S2U and U2S triacylglycerols, a novel medium-and long-chain triacylglycerol. These results demonstrated that the MPCB-DA-Lipase may be used as an efficient biocatalyst in lipid processing applications of food industries.

Expression and characterization of a novel lipase from Bacillus licheniformis NCU CS-5 for application in enhancing fatty acids flavor release for low-fat cheeses.

A novel lipase from Bacillus licheniformis NCU CS-5 was expressed in different Escherichia coli cells. The recombinant enzyme achieved a high activity (161.74 U/mL) with protein concentration of 0.27 mg/mL under optimal conditions at the large-scale expression of 12 h. The recombinant lipase showed optimal activity at 40 ℃ and pH 10.0, and maintained more than 80% relative activity after 96 h of incubation at pH 9.0-10.0. This typical alkaline lipase was activated under medium temperature conditions (30 and 45 ℃ for 96 h). The lipase exhibited a degree of adaptability in various organic solvents and metal ions, and showed high specificity towards triglycerides with short and medium chain fatty acids. Among different substrates, the lipase showed the strongest binding affinity towards pNPP (Km = 0.674 mM, Vmax = 950.196 µM/min). In the experiments of its application in enhancing fatty acids flavor release for low-fat cheeses, the lipase was found to hydrolyze cheeses and mainly increase the contents of butyric acid, hexanoic acid, caprylic acid and decanoic acid. The results from NMR and GC provided the possibility of enhancing fatty acids flavor released from low-fat cheeses by the lipolysis method.

Immobilization of lipase on ß-cyclodextrin grafted and aminopropyl-functionalized chitosan/Fe3O4 magnetic nanocomposites: An innovative approach to fruity flavor esters esterification.

The lipase from Bacillus licheniformis NCU CS-5 was immobilized onto ß-cyclodextrin (CD) grafted and aminopropyl-functionalized chitosan-coated Fe3O4 magnetic nanocomposites (Fe3O4-CTS-APTES-GA-ß-CD). Fourier transform infrared spectroscopy, thermogravimetry analysis, X-ray diffraction, scanning electron microscopy and transmission electron microscopy showed that not only the functionalized magnetic nanoparticles were synthesized but also the immobilized lipase was successfully produced. The immobilized lipase exhibited higher optimal pH value (10.5) and temperature (60℃) than the free lipase. The pH and thermal stabilities of the immobilized lipase were improved significantly compared to the free lipase. The immobilized lipase remained more than 80% of the relative activity at temperature of 60 ℃ and pH 12.0. The immobilized lipase also remained over 80% of its relative activity after 28 days of storage and 15 cycles of application. The application of the immobilized lipase in esterification of isoamyl acetate and pentyl valerate showed that maximum esterification efficiency was achieved in n-hexane having 68.0% and 89.2% respectively. Therefore, these results indicated that the Fe3O4-CTS-APTES-GA-ß-CD nanoparticles are novel carriers for immobilizing enzyme, and the immobilized lipase can be used as an innovative green approach to the synthesis of fruity flavor esters in food industry.

Assessment of the effect of ethanol extracts from Cinnamomum camphora seed kernel on intestinal inflammation using simulated gastrointestinal digestion and a Caco-2/RAW264.7 co-culture system.

Cinnamomum camphora seeds have multiple bioactivities. There were few studies on the effect of C. camphora seeds on intestinal inflammation in vitro and in vivo. The study aimed to investigate the effects of ethanol extracts from C. camphora seed kernel on intestinal inflammation using simulated gastrointestinal digestion and a Caco-2/RAW264.7 co-culture system. Results showed that the digested ethanol extracts (dEE) were rich in polyphenols, and a total of 17 compounds were tentatively identified using UPLC-LTQ-Orbitrap-MS/MS. dEE increased cell viability, while decreasing the production of reactive oxygen species, and the secretion and gene expression of inflammatory markers (NO, PGE2, TNF-α, IL-1ß and IL-6). dEE also down-regulated NF-κB/MAPK pathway activities by suppressing the phosphorylation of relevant signaling molecules (p65, IκBα, ERK and p38), as well as the expression of TLR4 receptor protein. Furthermore, dEE may improve intestinal barrier function by increasing the TEER value, and the expression of tight junction proteins (ZO-1, claudin-1 and occludin). The results suggest the ethanol extracts from C. camphora seed kernel may have strong anti-inflammatory activities, and a potential application in the prevention or treatment of intestinal inflammation and enhancement of intestinal barrier function in organisms.

Covalent modification by phenolic extract improves the structural properties and antioxidant activities of the protein isolate from Cinnamomum camphora seed kernel.

In this study, protein isolate (PI) and purified phenolic extract (PPE) were prepared from Cinnamomum camphora seed kernel (CCSK). The effects of covalent modification of PI by PPE at different concentrations (1, 2, 3, 4 and 5%, w/w) were investigated with respect to structural properties and antioxidant activities of protein. Fifteen bioactive compounds in PPE were tentatively identified by UPLC-ESI-MSn. With the increase of PPE concentration, the turbidity, covalent binding rate, phenolic content and color intensity of the PI-PPE complexes were gradually increased. Fourier transform infrared spectroscopy and circular dichroism spectroscopy analysis showed that the secondary and tertiary structures of the complexes were changed and became greater order than PI. Furthermore, the complexes exhibited stronger thermal stability and antioxidant activities than those of PI. These results suggested that the protein-phenolic covalent complexes obtained from CCSK may have great potential to be used in food formulations as functional ingredients.