Investigation on the interaction mechanisms for stability of preheated whey protein isolate with anthocyanins from blueberry.

Proteins and anthocyanins coexist in complex food systems. This research mainly studied the steady-state protective design and mechanism of the preheated protein against anthocyanins. Multispectral and molecular dynamics are utilized to illustrate the interaction mechanism between preheated whey protein isolate (pre-WPI) and anthocyanins. The pre-WPI could effectively protect the stability of anthocyanins, and the effect was better than that of the natural whey protein isolate (NW). Among them, NW after preheating treatment at 55 °C showed better protection against anthocyanin stability. Fluorescence studies indicated that pre-WPI there existed a solid binding affinity and static quenching for malvidin-3-galactoside (M3G). Multispectral data showed a significant variation in the secondary structure of pre-WPI. Furthermore, molecular dynamics simulation selects AMBER18 as the protein force field, and the results showed that hydrogen bonding participated as an applied force. Compared with NW, pre-WPI could better wrap anthocyanins and avoid damage to the external environment due to tightening of the pockets. Protein protects anthocyanins from degradation, and this protective effect is influenced by the preheating temperature of protein and the structure of protein. On the basis of the above results, it is possible to pinpoint the interaction mechanism between preheated proteins and anthocyanins.

The comparison and analysis of nutritional qualities of Chinese mitten crabs (Eriocheir sinensis) in rice field and pond culture modes.

The nutritional quality of three edible parts (gonads, hepatopancreas and muscles) of Chinese mitten crabs (CMCs) from rice field culture and pond culture was firstly compared in our current study. It was found that the contents of mineral elements and volatile compounds in rice CMCs were superior to those in pond CMCs, and the antioxidant enzyme activities of rice CMCs were markedly higher than those of pond CMCs. Besides, the total free amino acid levels in the edible parts of pond CMCs were higher than those of rice CMCs. Compared with other tissues, the nucleotide and equivalent umami concentrations of the gonads in female rice CMCs were the maximum. Overall, both types of crabs demonstrated good nutritional quality, which met human nutrition and dietary needs. In comparison, the quality of rice CMCs was better than that of pond CMCs.

Effects of α-casein on the excretion of blueberry anthocyanins via urine and feces: Analysis of their bioavailability.

Anthocyanins are bioactive compounds found in blueberries. However, their poor bioavailability restricts their functional activities in vivo, which is a challenging issue in the application of blueberry anthocyanins. Our current study utilized α-casein as a carrier and analyzed its influence on the excretion of blueberry anthocyanins in urine and feces in a rat model to reflect the enhanced bioavailability of blueberry anthocyanins by α-casein in vivo. The results showed that α-casein suppressed the excretive content of blueberry anthocyanins (malvidin-3-O-galacoside (M3G), cyanidin-3-O-glucoside (C3G), and delphinidin-3-O-glucoside (D3G)), increased the content of metabolites in urine (syringic acid, ferulic acid, 4-hydroxybenzoic acid, and vanillic acid), and reduced metabolite content in feces (syringic acid, ferulic acid, and gallic acid), indicating that α-casein was effective in controlling the excretion of blueberry anthocyanins and their metabolites. In summary, these results provided sufficient evidence for the positive effects of α-casein on the bioavailability of blueberry anthocyanins.

Transcriptome analysis of hepatopancreas of Chinese grass shrimp, Palaemonetes sinensis, infected by Enterocytospora artemiae.

The emergence of the microsporidian, Enterocytospora artemiae, has caused serious economic losses to the aquaculture industry of Palaemonetes sinensis. The hepatopancreas is the main digestive and immune organ of P. sinensis, and the main site of E. artemiae infection. We used next-generation sequencing to determine the effects of E. artemiae parasitism on the hepatopancreas of P. sinensis at the transcriptome level. The hepatopancreas of P. sinensis was parasitized by E. artemiae, and 881 differentially expressed genes (DEGs) were obtained, of which 643 were upregulated and 238 were downregulated. These DEGs are mainly involved in DNA replication, transcription, translation, immunity, and metabolism. Among them, the cellular processes of DNA replication, transcription and translation are significantly strengthened, which may be related to the use of host ATP and nucleic acid by E. artemiae to achieve proliferation and damage to host cells to enhance DNA replication and repair. Moreover, to defend against E. artemiae, some immune genes related to antioxidation, such as glutathione metabolism, seleno compound metabolism, and cytochrome p450 2L1, were significantly upregulated, but simultaneously, tumor necrosis factor, NF-κB inhibitor α, and other immune-related genes were significantly down regulated, indicating that the parasitism of E. artemiae led to a significant decline in the immune defense ability of P. sinensis. From the perspective of metabolism, the metabolism-related DEGs of retinol, glycine, serine, and threonine metabolism, were significantly downregulated, resulting in insufficient nutrient absorption and decreased energy supply of the P. sinensis, which in turn affected their growth. The differential genes and pathways identified in this study can provide a reference basis to further elucidate the pathogenic mechanism of P. sinensis infected with E. artemiae and the prevention and control of microsporidia disease.

Protective effects and mechanism of amino acids as chokeberry cyanidin and its glycoside protectant under the condition of vitamin C coexistence.

In the presence of vitamin C, cyanidin and cyanidin glycosides are degraded during the processing and storage of food products. To solve this issue, we investigated the protective effects and mechanism of action of five amino acids on the stability of cyanidin and its glycosides from chokeberry. The results showed that 0.3% tryptophan most effectively inhibited the degradation of cyanidin and its glycosides in the presence of vitamin C, under ultraviolet, dark, and sucrose-rich conditions. Fluorescence spectrum analysis showed that tryptophan could form noncovalent binding complexes with cyanidin-3-O-galactoside and cyanidin through hydrophobic and electrostatic forces and hydrogen bonds. Molecular docking results showed that the indole structure of tryptophan could form hydrophobic interactions with cyanidin-3-O-galactoside and cyanidin via hydrogen bonding, resulting in greater protection. Therefore, tryptophan could effectively protect cyanidin and its glycosides in cyanidin- and cyanidin glycoside-rich food products.

Conversion of condensed tannin from chokeberry to cyanidin: Evaluation of antioxidant activity and gut microbiota regulation.

Chokeberries contain a large amount condensed tannin. In this study, hot acid-alcohol treatment was used to convert the condensed tannin into cyanidin, so as to give them higher antioxidant activity and improve the function of gut microbiota. The total cyanidins yield was taken as the index. The effects of various factors on the total cyanidins yield were analysed by the single factor experiment and factor design experiment. In addition, the response surface methodology was used to obtain the optimal conversion conditions. The cyanidin composition and cellular antioxidant activity of products was detected. Through simulated digestion and fermentation in vitro, improvement of gut microbiota was evaluated. The results show that the product obtained by the optimal conversion treatment conditions, which could increase total cyanidins yield 1.50 folds to 28.88 mg/g. The total antioxidant activity and cellular antioxidant activity increased by 1.85 folds and 1.56 folds, reaching 3905.48 (µmol Vit C equiv./100 g FW) and 2329.31 (µmol QE/100 g FW), respectively. Conversion treatment could change the some negative effect of chokeberry on gut microbiota diversity into the positive effect.

A sub-freshness monitoring chitosan/starch-based colorimetric film for improving color recognition accuracy via controlling the pH value of the film-forming solution.

The demand for intelligent packaging in food sub-freshness monitoring is increasing. Herein, a pH and NH3 responsing colorimetric film (PS-CH-LCA) was fabricated based on potato starch (PS), chitosan (CH) and Lonicera caerulea L. anthocyanins (LCA) via controlling the pH value of the film-forming solution, and was applied to the real-time monitoring of shrimp freshness. The PS-CH-LCA pH 2.5 film exhibited the highest tensile strength (6.43 MPa), the lowest water solubility (33.11%) and the most sensitive color responsiveness. Morphological and structural results revealed that CH was attached to the surface of PS via hydrogen bond, and anthocyanins were well immobilized in the film-forming matrix. The sensitive color change and its high correlation with spoilage indices demonstrated the PS-CH-LCA pH 2.5 film well indicated fresh, sub-fresh, spoiled level of shrimp. The results solved the limitation of chitosan-based packaging films in undistinguishable colorimetric endpoints, providing a new strategy for indicating the sub-freshness of food packaging.

First report of Metschnikowia bicuspidata infection in Chinese grass shrimp (Palaemonetes sinensis) in China.

The Chinese grass shrimp (Palaemonetes sinensis) was found with a white turbidity appearance in the Panjin area. After dissection, typical symptoms of milky disease with hemolymph emulsification and noncoagulation were observed; however, the pathogen was unknown. In this study, we aimed to isolate the pathogen of the diseased P. sinensis. We found that the pathogen could grow on the fungal medium Bengal red, and microscopic examination showed that it reproduced by budding. Molecular identification of the isolated and purified yeast strain LNMB2021 based on 26S rDNA sequence showed that the pathogenic pathogen was Metschnikowia bicuspidata (GenBank OK094821), with 98.74% homology with M. bicuspidata strain LNES0119 (GenBank OK073903) and 98.56% with M. bicuspidata strain Liao (GenBank MT856369). The results of an artificial infection test showed that M. bicuspidata caused the same clinical symptoms in P. sinensis, and the isolated pathogen was still the same, which proved that P. sinensis was a new host of M. bicuspidata. Histopathological analysis showed that there were obvious pathological changes in the hepatopancreas and muscle tissue of the diseased P. sinensis. Identification of the pathogen is essential for the prevention and control of the disease and the healthy culture of P. sinensis. Furthermore, considering the transmissibility and cross-host transmission of M. bicuspidata, its risk of infecting other aquatic animals deserves high attention.

Effect of bovine serum albumin on the stability and antioxidant activity of blueberry anthocyanins during processing and in vitro simulated digestion.

The application of blueberry anthocyanins (ANs) was limited due to their low in-process stability and bioavailability. In our study, the stability and antioxidant capacity of ANs before and after adding bovine serum albumin (BSA) were examined by simulating various processing, storage (light, sucrose, and vitamin C (Vc)), and in vitro simulated digestion parameters. For this purpose, pH-differential method, high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS), peroxyl scavenging capacity assay, and cellular antioxidant assay were conducted. BSA at different concentrations, specifically at 0.15 mg/mL, inhibited the degradation of ANs and the loss of antioxidant capacity. The results suggest that BSA has a positive effect on ANs.

Effects of α-Casein on the Absorption of Blueberry Anthocyanins and Metabolites in Rat Plasma Based on Pharmacokinetic Analysis.

Blueberry anthocyanins are well known for their beneficial biological activities. However, the poor bioavailability of anthocyanins limits their functional capacity in vivo. Our current study aimed to detect the effects of α-casein on the absorption of blueberry anthocyanins and their metabolites in rats. Blueberry anthocyanins with and without α-casein were intragastrically administered to two groups of rats and their blood samples were collected within 24 h. Results illustrated that rapid absorption of anthocyanins was observed in the rat plasma, but their concentration was relatively low. With the complexation of α-casein, the maximum concentration (Cmax) of bioavailable anthocyanins and metabolites could increase by 1.5-10.1 times (P < 0.05 or P < 0.01). The promotional effect on the plasma absorption of malvidin-3-O-galactoside and vanillic acid was outstanding with the Cmax increasing from 0.032 to 0.323 and from 0.360 to 1.902 µg/mL, respectively (P < 0.01). Besides, the molecular docking models presented that anthocyanins could enter the structural cavity and interact with amino acid residues of α-casein, which was in accordance with the improved bioavailability of anthocyanins. Therefore, α-casein could assist more blueberry anthocyanins and their metabolites to enter blood circulation.

Effects of α-casein and ß-casein on the stability, antioxidant activity and bioaccessibility of blueberry anthocyanins with an in vitro simulated digestion.

Blueberry anthocyanins are well-known for their diverse biological functions. However, the instability during digestion results in their weak bioavailability. The current study aimed to investigate the alteration in the stability, antioxidant capacity and bioaccessibility of blueberry anthocyanins with the addition of α-casein and ß-casein in a simulated digestion system using pH differential method, HPLC-MS analysis, peroxyl scavenging capacity (PSC) assay, cellular antioxidant activity (CAA) and penetration test. The results showed that both α-casein and ß-casein could increase the stability of blueberry anthocyanins during intestinal digestion and protect their antioxidant capacity. Moreover, the addition of α-casein or ß-casein would enhance the bioaccessibility of blueberry anthocyanins. In conclusion, our study highlights that the interaction between α-casein or ß-casein with blueberry anthocyanins can protect the compounds against influences associated with the simulated digestion.

Effect of whey protein isolate on the stability and antioxidant capacity of blueberry anthocyanins: A mechanistic and in vitro simulation study.

The processing stability and antioxidant capacity of blueberry anthocyanins (ANs) in the presence of whey protein isolate (WPI) were examined. WPI was found to enhance both the stability and antioxidant activity of ANs during processing and simulated in vitro digestion, especially at a concentration of 0.15 mg·mL-1. Fluorescence and ultraviolet-visible absorption spectroscopy showed that ANs were primarily stabilized by hydrophobic forces between WPI and malvidin-3-O-galactoside (M3G), the major anthocyanin monomer. Circular dichroism and Fourier-transform infrared spectroscopy confirmed that the structure of WPI changed and the microenvironments of certain amino acid residues were modulated by non-covalent binding to M3G; furthermore, fewer α-helices and more ß-sheets were formed. Molecular docking studies revealed that WPI, especially immunoglobulin (IgG), contributed the most to ANs stability via hydrogen bonds and hydrophobic forces according to molecular docking scores (-141.30 kcal/mol). These results provided an important fundamental basis for improving the stabilities of ANs in milk systems.

Phytochemical profiles of rice and their cellular antioxidant activity against ABAP induced oxidative stress in human hepatocellular carcinoma HepG2 cells.

The phytochemical contents, peroxyl radical scavenging capacities (PSCs) and cellular antioxidant activities (CAAs) of free and bound fractions of rice were reported. Black rice had the highest total phenolic content and total flavonoid content in free and bound fractions, followed by red rice, brown rice, and polished rice. Black rice contained much more free phenolic compounds than other rice samples, such as cyanidin-3-O-glucoside, protocatechuic acid, and vanillic acid. Tocopherols and tocotrienols contents were highest in red rice, then in black rice, brown rice, and polished rice. PSCs and CAAs of free and bound fractions were in the order: black rice > red rice > brown rice > polished rice, except that bound CAA of red rice was higher than that of black rice. The cellular uptake rate of free phenolics was highest in red rice, while cellular uptake rates of bound phenolics were highest in brown rice and polished rice.

Protective effects of bovine serum albumin on blueberry anthocyanins under illumination conditions and their mechanism analysis.

This study investigates the effects of bovine serum albumin (BSA) on blueberry anthocyanins and their interaction. Findings showed that BSA could protect blueberry anthocyanins against degradation and retain their antioxidant activity at an ideal concentration of 0.15 mg/mL under three deteriorating treatments: illumination, vitamin C + illumination, and sucrose + illumination. The fluorescence and UV absorption spectra showed that malvidin-3-o-galactoside (M3G), the major monomer in blueberry anthocyanins, led to a static quenching of BSA and the binding site of M3G to BSA was approximately one. Further, the interaction was a spontaneous process with electrostatic interactions being the main force. CD spectra and synchronous fluorescence spectra presented alterations in the secondary structure and microenvironment of Trp and Tyr residues of BSA, respectively, upon interaction with M3G. Finally, molecular docking analysis showed that M3G mainly bound the II and III domains of BSA by hydrogen bonds and electrostatic interaction. In conclusion, our study highlights the protective effects of BSA on the stability and anti-oxidant activity of blueberry anthocyanins and their interaction analysis.

Blueberry polyphenols extract as a potential prebiotic with anti-obesity effects on C57BL/6 J mice by modulating the gut microbiota.

Polyphenols are known for their various health benefits. Blueberries are dietary sources of polyphenols with reported health benefits. However, the role of blueberry polyphenols in alleviating obesity is not completely understood. This study investigated the potential positive effect of blueberry polyphenol extract (PPE) on high-fat diet (HFD)-induced obesity in C57BL/6 J mice by modulation of the gut microbiota. Four-week-old C57BL/6 J mice were fed a normal-fat diet or HFD with or without PPE or Orlistat for 12 weeks. Mice fed HFD exhibited increased body weight and adipose tissue weight and disordered lipid metabolism. In contrast, PPE inhibited body weight gain and returned lipid metabolism to normal. Furthermore, 16S rRNA gene sequencing of the fecal microbiota suggested that PPE changed the composition of the gut microbiota in C57BL/6 J mice and modulated specific bacteria such as Proteobacteria, Deferribacteres, Actinobacteria, Bifidobacterium, Desulfovibrio, Adlercreutzia, Helicobacter, Flexispira, and Prevotella. Orlistat also improved obesity and metabolic alterations of HFD mice and modulated the composition of the gut microbiota. Our findings suggest that PPE, as a potential prebiotic agent, influences the gut microbiota to positively affect HFD-induced obesity in C57BL/6 J mice.