Simultaneous Ultrasound and Heat Enhance Functional Properties of Glycosylated Lactoferrin.

Protein-polysaccharide covalent complexes exhibit better physicochemical and functional properties than single protein or polysaccharide. To promote the formation of the covalent complex from lactoferrin (LF) and beet pectin (BP), we enhanced the Maillard reaction between LF and BP by using an ultrasound-assisted treatment and studied the structure and functional properties of the resulting product. The reaction conditions were optimized by an orthogonal experimental design, and the highest grafting degree of 55.36% was obtained by ultrasonic treatment at 300 W for 20 min and at LF concentration of 20 g/L and BP concentration of 9 g/L. The formation of LF-BP conjugates was confirmed by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) and Fourier transform infrared (FTIR) spectroscopy. Ultrasound-assisted treatment can increase the surface hydrophobicity, browning index, 1,1-diphenyl-2-picryl-hydrazyl (DPPH) and 2,2'-azinobis-(3-ethylbenzthiazoline-6-sulphonate) (ABTS) free radicals scavenging activity of LF due to the changes in the spatial configuration and formation of Maillard reaction products. The thermal stability, antioxidant activity and emulsifying property of LF were significantly improved after combining with BP. These findings reveal the potential application of modified proteins by ultrasonic and heat treatment.

Effect of Membrane Surface Modification Using Chitosan Hydrochloride and Lactoferrin on the Properties of Astaxanthin-Loaded Liposomes.

Astaxanthin-loaded liposomes were prepared by a thin-film ultrasonic method, and the effects of the different membrane surface modifiers chitosan hydrochloride (CH) and lactoferrin (LF) on the physicochemical stability of the liposomes and bioaccessibility of astaxanthin were studied. Based on the negative charge characteristics of egg yolk lecithin, LF and CH with positive charge were assembled on the surface of liposomes by an electrostatic deposition method. The optimal concentrations of modifiers were determined by particle size, zeta potential and encapsulation efficiency. The interaction between the liposomes and the coatings was characterized by Fourier Transform infrared spectroscopy. The stability of astaxanthin in different systems (suspension and liposomes) was investigated, and its antioxidant capacity and bioaccessibility were determined. The results showed that both membrane surface modifications could interact with liposomes and protect astaxanthin from oxidation or heat degradation and enhance the antioxidant activity of the liposome, therefore membrane surface modification played an important role in stabilizing the lipid bilayer. At the same time, the encapsulated astaxanthin exhibited higher in vitro bioaccessibility than the free astaxanthin. CH and LF modified liposomes can be developed as formulations for encapsulation and delivery of functional ingredients, providing a theoretical basis for the development of new astaxanthin series products.

A clarification of concepts related to the digestion and absorption of carotenoids and a new standardized carotenoids bioavailability evaluation system.

The published literature has shown that there are various evaluation methods for the process of carotenoids digestion and absorption. However, it was found that many concepts are ambiguous in the evaluation process, and the selection of evaluation methods is inappropriate and inaccurate. These deficiencies trouble readers, hamper comparisons among different studies, and generate controversy in different literature. Therefore, it is imperative to establish a complete and standardized system for evaluating the digestion and absorption process of carotenoids. This review begins by clarifying confusing concepts during the process of carotenoids digestion and absorption, including the release rate, micellization rate, bioaccessibility, relative bioavailability and absolute bioavailability. Then this review discusses relevant factors affecting the key process of the digestion and absorption of carotenoids. Finally, a more specific and standardized system for evaluating carotenoids bioavailability was suggested based on four dimensions: intake, digestion, absorption and metabolic process. Clarifying concepts such as digestion and absorption and standardizing corresponding research methods will help to obtain reliable data and support interoperability and comparisons across studies.

Development of astaxanthin-loaded layer-by-layer emulsions: physicochemical properties and improvement of LPS-induced neuroinflammation in mice.

Astaxanthin (AST) has been shown to have neuroprotective effects; however, its bioavailability in vivo is low due to its hydrophobic properties. In this study, lactoferrin (LF) was prepared by heat-treatment at different temperatures, and on this basis, a layer-by-layer self-assembly method was used to construct double-layer emulsions with LF as the inner layer and polysaccharide (beet pectin, BP or carboxymethyl chitosan, CMCS) as the outer layer. Then AST was encapsulated in the emulsions and their physiochemical properties and function were investigated. The results indicated that high temperature heated LF (95 °C) showed a more stable structure than the lower temperature one, and the exposed internal nonpolar groups of LF could give the emulsion an enhanced stability. The rheology results showed that compared with CMCS, the double-layer emulsion formed by BP had a higher viscosity. In addition, the 95 °C LF-AST-BP emulsion showed the best stability among all the bilayer emulsions. The best emulsion was then used as a model drug to investigate its effects on lipopolysaccharide (LPS)-induced neuroinflammation and learning-memory loss in C57BL/6J mice. Through animal behavioral experiments, it was found that dietary supplementation with the AST emulsion could effectively improve the brain cognitive and learning memory impairment caused by inflammation. Transmission electron microscopy, mRNA and western blotting results also illustrated that the AST emulsion could alleviate neuroinflammation caused by LPS. This study provides a feasible scheme for exploring an AST loaded system and may be suitable for food and drug applications.

Effects of different doses lipopolysaccharides on the mucosal barrier in mouse intestine.

Lipopolysaccharide (LPS), an important component in the outer membrane of the cell wall of Gram-negative bacteria, can induce a systemic inflammatory response and play an important role in bacterial infection and disease evolution. The thick layer of mucus covering the small intestinal villus acts primarily to the first barrier from damage by toxic substances. We aimed to study the effects of LPS on the intestinal mucus layer barrier. The results showed that the thickness of the mucus layer was significantly increased by a low dose of LPS. Further, LPS can cross this barrier into the blood, put the body in a state of chronic low-grade inflammation, and activate the body's immune response. However, after a long-term high dose of LPS exposure, a large number of lysosomes in goblet cells caused a loss of function, and mucus layer thickness was significantly decreased. A large amount of LPS stuck to the mucus, leading to normal LPS and inflammatory cytokines level of plasma. The intestinal tissue morphology was damaged, and many immune cells died through necrosis in the intestine. Collectively, the function of the goblet cell was normal, a low dose of LPS cannot be stuck to the mucus layer. However, a high dose of LPS stuck to the mucus when goblet cells caused a loss of function, which can be directly linked to the severity of the immunosuppression in the body.

Effects of Long-time Exposure to Lipopolysaccharide on Intestinal Lymph Node Immune Cells and Antibodies Level in Mice.

BACKGROUND: Endotoxin, widely present in the living environment of humans and animals, leads to endotoxemia during a short period. However, the long-term effects of endotoxin on immune function are unclear. OBJECTIVE: To determine the importance of long-term endotoxin treatment on function of immune system. METHODS: The mice were treated with different doses of lipopolysaccharide (LPS) for a month; the collected samples were then analyzed in terms of value changes in hematological parameters, lymphocyte subtypes, and immunoglobulins level. RESULTS: The number of monocytes (MONO) and neutrophils (NEU) in the three treatment groups was significantly lower than the control after 30 days. However, the proportion of CD8+ T lymphocytes showed a rising trend in the mesenteric lymph nodes (MLNs) and Peyer's patches (PPs) while the CD4+ T cell was reduced. At the same time, a decrease was observed in the percentage of CD19+CD38+ B lymphocytes. Interestingly, the change of lymphocytes in PPs was more significant than that in MLNs, suggesting that immune response in the PPs occurred before the MLNs. Consistent with the changes in B cells, the content of IgA and IgG showed a downward trend. CONCLUSION: Long-term exposure to low-dose endotoxin had little or no effect on the immune function of the body, suggesting that the endotoxin can be rapidly eliminated by the immune system. Nonetheless, the number of immune cells was reduced in the high-dose group. T- and B-lymphocytes were significantly reduced, resulting in a decrease in immunoglobulin level, and showing a significant immune suppression state.

Sesamol incorporated cellulose acetate-zein composite nanofiber membrane: An efficient strategy to accelerate diabetic wound healing.

Recently, the function of nanofiber membranes prepared from electrospinning in accelerating wound healing has attracted wide attention. In this study, novel nanofiber membranes consisted of cellulose acetate (CA) and zein were fabricated to provide efficient delivery vehicles for sesamol, and then the effect of sesamol-loaded composite nanofiber membranes on the wound healing of diabetic mice was studied. It was found the critical concentration of CA was between 15% and 25% (w/v), and the most suitable concentration of stabilizing fibers was 22.5%. When the CA/zein ratio was 12:8, the fiber obtained small diameter and uniform distribution, stable intermolecular structure, low infiltration speed and high stability in water. The composite nanofiber membrane with high-dose sesamol (5% of total polymer concentration, w/w) promoted formation of myofibroblasts by enhancing TGF-ß signaling pathway transduction, and promoted keratinocyte growth by inhibiting chronic inflammation in wounds, thus enhancing wound healing in diabetic mice. This study can further broaden the application range of sesamol, CA and zein, and provide reference for the design and development of new wound dressings in the future.