Development and characterization of emulsion gels prepared via gliadin-based colloidal particles and gellan gum with tunable rheological properties for 3D printed dysphagia diet

Dysphagia, a condition characterized by difficulty swallowing, has emerged as a threat to health. Herein, we investigated the feasibility of preparing a novel 3D-printed dysphagia diet using emulsions and gellan gum. A gel network was facilitated by the inclusion of gellan gum, which also helped to reduce the size of the oil droplets. Emulsion gels (with 0.3 %-0.5 % gellan gum) were stable at 25 °C for 30 days and tolerated a high ionic concentration of 800 mmol L-1. Emulsion gels remained stable after heat treatment and centrifugation. The excellent stability of the emulsion gels was related to the three-dimensional network developed by the gellan gum. The rheological results validated the solid-state behavior, shear thinning behavior and structural recovery of emulsion gels. Emulsion gels with 0.3 %-0.5 % gellan gum were suitable for 3D printing since they had high printing accuracy, self-support, and smooth surface texture. International Diet Standardization Initiative (IDDIS) tests have shown that emulsion gels can be classified as a level 3-5 dysphagia diet. In addition, the bioaccessibility of astaxanthin increased 1.7 times after being encapsulated by emulsion gels. Overall, these results demonstrate the potential of emulsion gels in the development of novel 3D-printed diets for dysphagia and bioactive protection.

In vivo anti-obesity efficacy of fucoxanthin/HP-β-CD nanofibers in high-fat diet induced obese mice

Fucoxanthin (Fx) has poor water solubility and bioavailability, which limits its application in the food industry. To improve the physicochemical properties of Fx, hydroxypropyl-β-cyclodextrin (HP-β-CD) encapsulated Fx nanofibers (Fx/HP-β-CD nanofibers) were fabricated via electrospinning without using polymer. Molecular docking analysis showed the Fx/HP-β-CD nanofibers contained Fx and HP-β-CD at 1:2. Morphological analysis revealed the nanofibers were homogeneous without beads, having a diameter around 499 nm. The thermostability of Fx was significantly improved after encapsulationg by HP-β-CD. Animal studies showed that there was a 14% decrease of body weight, 11% white adipose tissue reduction and 9% lower of liver triglyceride for the mice treated with Fx/HP-β-CD nanofibers as compared with that of Fx treated mice. The total cholesterol was reduced by 23% in mice serum after treatment with Fx/HP-β-CD as compared with that of Fx. Interestingly, the Fx/HP-β-CD in this study could attenuate the testicular histopathology in obese mice.

Preparation of Polysaccharide-Protein Hydrogels with an Ultrafast Self-Healing Property as a Superior Oral Delivery System of Probiotics

Oral administration of probiotic supplements can effectively regulate intestinal disorders. However, harsh gastrointestinal conditions greatly limit the bioavailability of probiotics. In this work, biomass-derived polysaccharide-protein hydrogels (Dex-sBSA hydrogels) were constructed as an oral probiotic delivery system. The hydrogel encapsulation significantly promoted the growth and proliferation of probiotics and protected them from gastric acid, bile salts, reactive oxygen species, and antibiotics. In vivo experiments demonstrated that the hydrogel encapsulation significantly enhanced the bioavailability of probiotics, of which the cell number in the intestine, colon, and cecum was 35 times, 8 times, and 203 times higher than the free one, respectively. Attributed to the superior ultrafast self-healing property, the Dex-sBSA hydrogel successfully prevented the probiotics from quick elimination and prolonged the retention time in the gut, providing great possibilities for colonization and proliferation. These results clearly indicate the great potential of the Dex-sBSA hydrogel as a superior oral delivery system for probiotics.

Norovirus outbreaks in hospitals in China: a systematic review

BACKGROUND

Norovirus outbreaks in hospitals can potentially impair patient care and result in significant financial expenses. There is currently limited information on hospital norovirus outbreaks in the Chinese mainland.

AIM

To systematically review the published literature to describe the characteristics of norovirus outbreaks in Chinese mainland hospitals to facilitate prompt identification and control of outbreaks.

METHODS

A systematic review was performed according to the Preferred Reporting Items for Systematic Review and Meta-Analysis standards. Databases including PubMed, Web of Science, and Chinese Journals Online databases (China National Knowledge Infrastructure (CNKI), Chinese Wan Fang digital database (WANFANG) were searched from inception to July 18th, 2022.

FINDINGS

A total of 41 norovirus Chinese hospital outbreaks occurring before July 18th, 2022 were reported in 32 articles. Most reported outbreaks were from Shanghai and Beijing, and occurred in December and January. Cases were mainly adults. The male:female ratio was 1.22:1. The majority of cases in norovirus outbreaks were hospitalized patients (56.82%); medical staff were affected in 15 outbreaks. Norovirus outbreaks occurred in both private and public hospitals, and in secondary and tertiary care centres, and occurred mainly in internal medicine and geriatric departments. Person-to-person transmission was the primary transmission mode and GII was more prevalent.

CONCLUSION

Norovirus outbreaks in hospitals can affect both patients and healthcare workers, sometimes causing serious financial losses. In order to have a more complete understanding of the disease burden caused by norovirus outbreaks, surveillance needs to be established in hospitals.

Paper-Based Microfluidic Chips for Food Hazard Factor Detection: Fabrication, Modification, and Application

Food safety and quality are paramount concerns for ensuring the preservation of human life and well-being. As the field of food processing continues to advance, there is a growing interest in the development of fast, instant, cost-effective, and convenient methods for detecting food safety issues. In this context, the utilization of paper-based microfluidic chips has emerged as a promising platform for enabling rapid detection, owing to their compact size, high throughput capabilities, affordability, and low resource consumption, among other advantages. To shed light on this topic, this review article focuses on the functionalization of paper-based microfluidic surfaces and provides an overview of the latest research and applications to colorimetric analysis, fluorescence analysis, surface-enhanced Raman spectroscopy, as well as their integration with paper-based microfluidic platforms for achieving swift and reliable food safety detection. Lastly, the article deliberates on the challenges these analytical methods and presents insights into their future development prospects in facilitating rapid food safety assessment.

On-Chip Precisely Controlled Preparation of Uniform Core-Shell Salmon Byproduct Protein/Polysaccharide Microcapsules for Enhancing Probiotic Survivability in Fruit Juice

The increasing demand for probiotic-fortified fruit juices stems from the dietary requirements of individuals with dairy allergies, lactose intolerance, and vegetarian diets. However, a notable obstacle arises from the degradation of probiotics in fruit juices due to their low pH levels and harsh gastrointestinal conditions. In response, this study proposes an innovative approach utilizing a microfluidic chip to create core-shell microcapsules that contain Lactobacillus plantarum Lp90. This method, based on internal-external gelation, forms highly uniform microcapsules that fully enclose the core, which consists of oil-in-water Pickering emulsions stabilized by salmon byproduct protein and sodium alginate. These emulsions remain stable for up to 72 h at a 1% sodium alginate concentration. The shell layer incorporates kelp nanocellulose and sodium alginate, thus improving the thermal properties. Furthermore, compared to free probiotics, the multilayer structure of the core-shell microcapsules provides a robust barrier, resulting in significantly enhanced probiotic stability. These findings introduce a novel strategy for augmenting probiotic delivery in functional fruit juice beverages, promising solutions to the challenges encountered during their development.

Tuning the Microstructures of Electrospray Multicore Alginate Microspheres for the Enhanced Delivery of Astaxanthin

Multicore alginate microspheres (MCPs) have been demonstrated as promising carriers for bioactive substances. Herein, the influence of the size of the inner core on the bioaccessibility of astaxanthin (AST) was investigated using both in vitro and in vivo methods. MCPs with different inner core sizes were fabricated in which the oil-in-water emulsion with different oil droplet sizes was embedded in alginate microspheres (AST@MCPs) via the electrospray technology. The AST@MCPs appeared as a uniform sphere with an average size of 300 μm. The AST encapsulation efficiency in the AST@MCPs was determined to be more than 68%, which was independent of the inner core size. The bioaccessibility of AST increased from 38.3 to 83.2% as the size of the inner core decreased. Furthermore, the anti-inflammatory activity of AST@MCPs after in vitro simulated digestion was evaluated by LPS-induced RAW264.7 cells. The results suggested that AST@MCPs with a smaller inner core size exhibited a stronger anti-inflammatory activity, which further proved the results obtained from in vitro simulated digestion. As expected, the oral administration of AST@MCPs significantly mitigated colitis symptoms in DSS-induced ulcerative colitis mice. Compared with AST@MCPs with larger inner cores, AST@MCPs with smaller inner cores reflect stronger anti-inflammatory activity in vivo. These results suggested that the bioaccessibility of AST in MCPs increased significantly with the decrease in the inner core size, which may be attributed to the rapid formation of micelles in the intestine. This work provides a simple and efficient strategy to prepare microspheres for the enhanced delivery of AST, which has important implications for the design of health-promoting foods.

Dandelion (Taraxacum mongolicum) Extract Alleviated H2O2-Induced Oxidative Damage: The Underlying Mechanism Revealed by Metabolomics and Lipidomics

Dandelion has received wide attention in food and medicine fields due to its excellent antioxidant properties. Nonetheless, the underlying mechanism of this action has not yet been fully clarified, particularly at the metabolic level. Herein, the effects of dandelion extract (DE) on H2O2-induced oxidative damage was investigated. The results indicate that the DE alleviated H2O2-induced cell damage (increased by 14.5% compared to H2O2 group), reduced the reactive oxygen species (ROS) level (decreased by 80.1% compared to H2O2 group), maintained the mitochondrial membrane potential (MMP) level, and increased antioxidant-related enzyme activities. Importantly, the metabolic response of PC12 cells indicates that H2O2 disturbed phospholipid metabolism and damaged cell membrane integrity. In addition, energy metabolism, the central nervous system, and the antioxidant-related metabolism pathway were perturbed. In contrast, DE rescued the H2O2-induced metabolic disorder and further alleviated oxidative damage. Collectively, these findings provide valuable stepping stones for a discussion of the mechanism and show the promise of DE as a suitable additive for functional food products.

Recent advances on natural colorants-based intelligent colorimetric food freshness indicators: fabrication, multifunctional applications and optimization strategies

With the increasing concerns of food safety and public health, tremendous efforts have been concentrated on the development of effective, reliable, nondestructive methods to evaluate the freshness level of different kinds of food. Natural colorants-based intelligent colorimetric indicators which are typically constructed with natural colorants and polymer matrices has been regarded as an innovative approach to notify the customers and retailers of the food quality during the storage and transportation procedure in real-time. This review briefly elucidates the mechanism of natural colorants used for intelligent colorimetric indicators and fabrication methodologies of natural colorants-based food freshness indicators. Subsequently, their multifunctional applications in intelligent food packaging systems like antioxidant packaging, antimicrobial packaging, biodegradable packaging, UV-blocking packaging and inkless packaging are well introduced. This paper also summarizes several optimizing strategies for the practical application of this advanced technology from different perspectives. Strategies like adopting a hydrophobic matrix, constructing double-layer film and encapsulation have been developed to improve the stability of the indicators. Co-pigmentation, metal ion complexation, pigment-mixing and using substrates with high surface area are proved to be effective to enhance the sensitivity of the indicators. Approaches include multi-index evaluation, machine learning and smartphone-assisted evaluation have been proven to improve the accuracy of the intelligent food freshness indicators. Finally, future research opportunities and challenges are proposed. Based on the fundamental understanding of natural colorants-based intelligent colorimetric food freshness indicators, and the latest research and findings from literature, this review article will help to develop better, lower cost and more reliable food freshness evaluation technique for modern food industry.

Microfluidic fabrication of size-controlled nanocarriers with improved stability and biocompatibility for astaxanthin delivery

Improving the stability of astaxanthin (AST) is a vital way to enhance its oral bioavailability. In this study, a microfluidic strategy for the preparation of astaxanthin nano-encapsulation system was proposed. Thanks to the precise control of microfluidic and the rapid preparation ability of the Mannich reaction, the resulting astaxanthin nano-encapsulation system (AST-ACNs-NPs) was obtained with average sizes of 200 nm, uniform spherical shape and high encapsulation rate of 75%. AST was successfully doped into the nanocarriers, according to the findings of the DFT calculation, fluorescence spectrum, Fourier transform spectroscopy, and UV-vis absorption spectroscopy. Compared with free AST, AST-ACNs-NPs showed better stability under the conditions of high temperature, pH and UV light with<20% activity loss rate. The nano-encapsulation system containing AST could significantly reduce the hydrogen peroxide produced by reactive oxygen species, keep the potential of the mitochondrial membrane at a healthy level, and improve the antioxidant ability of H₂O₂-induced RAW 264.7 cells. These results indicated that microfluidics-based astaxanthin delivery system is an effective solution to improve the bioaccessibility of bioactive substances and has potential application value in food industry.

Pickering emulsion stabilized by Haematococcus pluvialis protein particles and its application in dumpling stuffing

In this study, the oil-in-water Pickering emulsions were prepared using Haematococcus Pluvialis protein (HPP) particles as an emulsifier by a simple one-step emulsification method. The internal oil phase was as high as 70 % due to the excellent emulsifying properties of HPP, and the average size of oil droplets in the emulsion was around 20 μm. The emulsion prepared by 2.5 % HPP with the oil phase ratio of 70 % showed the best stability after 14 days of storage, and the emulsion could maintain stability at acidic condition, high ionic strength, low and high temperatures. However, all emulsion samples exhibited shear thinning phenomenon, and the higher HPP concentration and oil phase ratio led to greater G' and G″ modulus. NMR relaxation results showed that high concentration HPP could limit the mobility of free water in the emulsion and improve the emulsion stability. The HPP-stabilized emulsion could inhibit the oxidation of oil phase during storage due to the DPPH and ABTS radical scavenging activity of astaxanthin (AST) in HPP. Finally, the nutritional microspheres based on HPP-stabilized emulsion showed good stability in traditional dumplings and could reduce the loss of AST and DHA in algae oil during the boiling of dumplings.

Preparation and evaluation of ovalbumin-fucoidan nanoparticles for nicotinamide mononucleotide encapsulation with enhanced stability and anti-aging activity

Nicotinamide mononucleotide (NMN) has been recognized as a promising bio-active compound in relieving aging-related mitochondrial dysfunction. Self-assembled nanoparticles were prepared based on interaction between ovalbumin (OVA) and fucoidan to improve the stability and bio-accessibility of NMN. The OVA-fucoidan nanoparticles (OFNPs) displayed outstanding thermal stability and entrapment ability of NMN. The reactive oxygen species (ROS) analysis and senescence-associated β-galactosidase (SA-β-gal) staining characterization indicated that NMN encapsulated by OFNPs could effectively alleviate the cellular senescence of d-galactose-induced senescent cells. In vivo Caenorhabitis elegans experiment demonstrated that NMN-loaded OFNPs caused less accumulation of lipofuscin and protected NMN from thermal damage. Compared with free NMN, the NMN-loaded OFNPs prolonged lifespan from 28 to 31 days, increased 26% reproductive ability, and improved 12% body length of Caenorhabitis elegans. The results indicated that the use of nanocarriers could be a good strategy to improve anti-oxidative stress and anti-aging ability of NMN.

First Dark Matter Search Results from the LUX-ZEPLIN (LZ) Experiment

The LUX-ZEPLIN experiment is a dark matter detector centered on a dual-phase xenon time projection chamber operating at the Sanford Underground Research Facility in Lead, South Dakota, USA. This Letter reports results from LUX-ZEPLIN's first search for weakly interacting massive particles (WIMPs) with an exposure of 60 live days using a fiducial mass of 5.5 t. A profile-likelihood ratio analysis shows the data to be consistent with a background-only hypothesis, setting new limits on spin-independent WIMP-nucleon, spin-dependent WIMP-neutron, and spin-dependent WIMP-proton cross sections for WIMP masses above 9  GeV/c^{2}. The most stringent limit is set for spin-independent scattering at 36  GeV/c^{2}, rejecting cross sections above 9.2×10^{-48}  cm at the 90% confidence level.

Computer Vision-Based Artificial Intelligence-Mediated Encoding-Decoding for Multiplexed Microfluidic Digital Immunoassay

Digital immunoassays with multiplexed capacity, ultrahigh sensitivity, and broad affordability are urgently required in clinical diagnosis, food safety, and environmental monitoring. In this work, a multidimensional digital immunoassay has been developed through microparticle-based encoding and artificial intelligence-based decoding, enabling multiplexed detection with high sensitivity and convenient operation. The information encoded in the features of microspheres, including their size, number, and color, allows for the simultaneous identification and accurate quantification of multiple targets. Computer vision-based artificial intelligence can analyze the microscopy images for information decoding and output identification results visually. Moreover, the optical microscopy imaging can be well integrated with the microfluidic platform, allowing for encoding-decoding through the computer vision-based artificial intelligence. This microfluidic digital immunoassay can simultaneously analyze multiple inflammatory markers and antibiotics within 30 min with high sensitivity and a broad detection range from pg/mL to μg/mL, which holds great promise as an intelligent bioassay for next-generation multiplexed biosensing.

Carbon Quantum Dots from Roasted Coffee Beans: Their Degree and Mechanism of Cytotoxicity and Their Rapid Removal Using a Pulsed Electric Field

Carbon quantum dots (CQDs) from heat-treated foods show toxicity, but the mechanisms of toxicity and removal of CQDs have not been elucidated. In this study, CQDs were purified from roasted coffee beans through a process of concentration, dialysis and lyophilization. The physical properties of CQDs, the degree and mechanism of toxicity and the removal method were studied. Our results showed that the size of CQDs roasted for 5 min, 10 min and 20 min were about 5.69 ± 1.10 nm, 2.44 ± 1.08 nm and 1.58 ± 0.48 nm, respectively. The rate of apoptosis increased with increasing roasting time and concentration of CQDs. The longer the roasting time of coffee beans, the greater the toxicity of CQDs. However, the caspase inhibitor Z-VAD-FMK was not able to inhibit CQDs-induced apoptosis. Moreover, CQDs affected the pH value of lysosomes, causing the accumulation of RIPK1 and RIPK3 in lysosomes. Treatment of coffee beans with a pulsed electric field (PEF) significantly reduced the yield of CQDs. This indicates that CQDs induced lysosomal-dependent cell death and increased the rate of cell death through necroptosis. PEF is an effective way to remove CQDs from roasted coffee beans.

A bifunctional hepatocyte-mitochondrion targeting nanosystem for effective astaxanthin delivery to the liver

A bifunctional hepatocyte-mitochondrion targeting nanosystem was prepared for astaxanthin by conjugating lactobionic acid (LA) and triphenylphosphonium-modified 2-hydroxypropyl-β-cyclodextrin onto sodium alginate. Hepatocyte-targeting evaluation indicated that the fluorescence intensity of HepaRG cells treated with the bifunctional nanosystem increased 90.3%, which was greater than that (38.7%) of the LA-only targeted nanosystem. The Rcoloc was 0.81 for the bifunctional nanosystem in mitochondrion-targeting analysis, which was greater than that (0.62) of the LA-only targeted nanosystem. The reactive oxygen species (ROS) level of the astaxanthin bifunctional nanosystem treated group significantly reduced to 62.20%, lower than that of free astaxanthin (84.01%) and LA-only targeted group (73.83%). Mitochondrial membrane potential recovered 97.35% in the astaxanthin bifunctional nanosystem treated group while the LA-only targeted group recovered 77.45%. The accumulation of bifunctional nanosystem in liver increased by 31.01% compared to the control. These findings indicated that the bifunctional nanosystem was beneficial for astaxanthin delivery in the liver precision nutrition intervention.

Pickering emulsions stabilized with a spirulina protein-chitosan complex for astaxanthin delivery

Astaxanthin (AXT) is a lipid-soluble carotenoid with good anti-oxidation, hepatic steatosis reduction, anti-inflammation, and intestinal microbiota regulation ability, whose poor stability and pH vulnerability limit its bioavailability. Spirulina protein (SP) derived from spirulina has good emulsifying ability with potential application in nutraceuticals, medicines, and cosmetics. In this study, Pickering emulsions were prepared using a SP-chitosan (CS) complex as an emulsifier. The particle size, zeta potential, and three-phase contact angle of the SP-CS complex with different SP to CS ratios were investigated. A mass ratio of 1 : 2.5 SP-CS complex showed a good emulsifying ability in preparing Pickering emulsion. A higher storage modulus and viscoelasticity were observed with higher SP-CS complex concentrations and oil fractions. The SP-CS Pickering emulsion significantly improved the stability of AXT in different environments. The lipid release rate and AXT bioavailability after digestion of 3 wt% SP-CS complex-stabilized Pickering emulsion reached 70.54 ± 1.59% and 36.60 ± 3.44%, respectively. The results indicated that the SP-CS complex could act as a Pickering emulsion stabilizer and had the potential to deliver protective hydrophobic AXT.

Simultaneous detection of ultraviolet irradiation and vitamin C using an all-carbon-based integrated wearable system powering by a micro-supercapacitor

Ultraviolet (UV) radiation is a harmful exogenous factor for human skin. Wearable UV photodetectors can monitor UV exposure in the surroundings, and wearable vitamin C (V_C) sensors tracking the levels in the human body present the potential ability to defend the UV radiation. Herein, we reported on the fabrication of an all-in-one wearable system with a UV photodetector and V_C sensor powered by a micro-supercapacitor. Based on direct laser writing carbonization of polyimide sheets, the patterned electrodes and interconnects of the circuit were fabricated by a facile one-step operation, obtaining an all-carbon-based integrated system. Such a system exhibited outstanding energy storage ability (56.2 μWh cm^-2 at 4.17 mW cm^-2), high areal capacitance (1.06 mF cm^-2 at 5 mV s^-1), satisfying capacitive stability, and good mechanical flexibility. The UV photodetector and the V_C sensor were powered to obtain a linear range of UV intensity from 11 to 44 μW cm^-2 (equivalent to Ultraviolet Index 4.4 to 17.6), and V_C levels of 1.0-200 μM with a low limit of detection of 0.83 μM. Furthermore, the integrated system was successfully applied to the determination of V_C in commercial beverage and human sweat samples. This work provided a simple and promising method to fabricate integrated wearable systems for on-site providing information on the UV intensity of the external environment and the V_C level of the human body simultaneously.

Hepatic-targeted delivery of astaxanthin for enhanced scavenging free radical scavenge and preventing mitochondrial depolarization

Astaxanthin (AST), as natural hydrophobic nutrition, has exhibited health-promoting benefits for its outstanding antioxidant property. However, most studies tend to enhance its stability and solubility while the targeted delivery of AST is limited. In this study, liver-targeted nanocarriers were designed and prepared by lactobionic acid-modified (2-hydroxypropyl-β-cyclodextrin) for efficient controlled delivery of AST. The minimum average size of AST nanoparticles was about 98 nm with a polydispersity index (PDI) of 0.41. The lactobionic acid-modified AST nanoparticles exhibited significant cellular uptake, and an admirable ability to scavenge free radicals for H₂O₂-induced HepaRG cells in preventing mitochondrial depolarization. Moreover, accumulation of AST nanoparticles in liver was observed due to the modification of lactobionic acid (LA) of the nanocarriers through the specific binding of LA-asialoglycoprotein receptors. The results in this study provided a new idea for liver-specific nutrition delivery of AST in developing functional food for liver disease nutrition intervention.

Engineering fucoxanthin-loaded probiotics' membrane vesicles for the dietary intervention of colitis

Extracellular vesicles (EVs) are very attractive as carriers of active components due to their good immunological and their ability to penetrate the physiological barrier that synthetic delivery carriers cannot penetrate. However, the low secretion capacity of EVs limited its widespread adoption, let alone the lower yield of EVs loaded with active components. Here, we report a large-scale engineering preparation strategy of synthetic probiotic membrane vesicles for encapsulating fucoxanthin (FX-MVs), an intervention for colitis. Compared with the EVs naturally secreted by probiotics, the engineering membrane vesicles showed a 150-fold yield and richer protein. Moreover, FX-MVs improved the gastrointestinal stability of fucoxanthin and inhibited H₂O₂-induced oxidative damage by scavenging free radicals effectively (p < 0.05). The in vivo results showed that FX-MVs could promote the polarization of macrophages to M2 type, prevent the injury and shortening of colon tissue (p < 0.05), and improve the colonic inflammatory response. Consistently, proinflammatory cytokines were effectively suppressed after FX-MVs treatment (p < 0.05). Unexpectedly, such engineering FX-MVs could also reshape the gut microbiota communities and improve the abundance of short-chain fatty acids in the colon. This study lays a foundation for developing dietary interventions using natural foods to treat intestinal-related diseases.

Engineering probiotics-derived membrane vesicles for encapsulating fucoxanthin: evaluation of stability, bioavailability, and biosafety

Due to the multiplex absorption barrier in the gastrointestinal tract, the low oral bioavailability of many lipophilic chemicals limits their range of applications. Biomimetic nanovesicles offered unique advantages in overcoming multiple barriers to oral absorption and improving the oral bioavailability of encapsulated water-insoluble compounds. Here, we report an engineering preparation strategy of synthetic probiotic membrane vesicles for encapsulating fucoxanthin. Fucoxanthin-loaded synthetic membrane vesicles (FX-MVs) were spherical with a particle size of 412 nm. Fourier transform infrared spectroscopy and ultraviolet-visible absorption spectroscopy results revealed that fucoxanthin was successfully doped into the membrane vesicles. Moreover, FX-MVs improved the stability of fucoxanthin under heating and UV irradiation conditions. In vitro experiments indicated that FX-MVs could effectively promote the cell uptake, and the mechanism mainly involved endocytosis. Simultaneously, ex vivo experiments confirmed that FX-MVs enhanced intestinal retention. Finally, the oral biosafety of FX-MVs was evaluated. The mice fed FX-MVs did not show toxicity signs and adverse effects, based on the results of clinical observation, body weight, hematology, clinical biochemistry, and organ pathology. Altogether, these results suggest that synthetic probiotic membrane vesicles can be used as safe delivery carriers to improve the stability and bioavailability of hydrophobic food bioactive ingredients.

Nanostructured steady-state nanocarriers for nutrients preservation and delivery

Food bioactives possess specific physiological benefits of preventing certain diet-related chronic diseases or maintain human health. However, the limitations of the bioactives are their poor stability, lower water solubility and unacceptable bioaccessibility. Structure damage or degradation is often found for the bioactives under certain environmental conditions like high temperature, strong light, extreme pH or high oxygen concentration during food processing, packaging, storage and absorption. Nanostructured steady-state nanocarriers have shown great potential in overcoming the drawbacks for food bioactives. Various delivery systems including solid form delivery system, liquid form delivery system and encapsulation technology have been developed. The embedded food nutrients can largely decrease the loss and degradation during food processing, packaging and storage. The design and application of stimulus and targeted delivery systems can improve the stability, bioavailability and efficacy of the food bioactives upon oral consumption due to enzymatic degradation in the gastrointestinal tract. The food nutrients encapsulated in the smart delivery system can be well protected against degradation during oral administration, thus improving the bioavailability and releazing controlled or targeted release for food nutrients. The encapsulated food bioactives show great potential in nutrition therapy for sub-health status and disease. Much effort is required to design and prepare more biocompatible nanostructured steady-state nanocarriers using food-grade protein or polysaccharides as wall materials, which can be used in food industry and maintain the human health.

Pickering emulsions stabilized by Chlorella pyrenoidosa protein-chitosan complex for lutein encapsulation

Lutein has many physiological functions like antioxidation, anti-cancer, and anti-inflammation, which presents good potential in the development of functional food for eye protection. However, the hydrophobicity and harsh environment factors during digestive absorption process will greatly reduce lutein bioavailability. In this study, Chlorella pyrenoidosa protein-chitosan complex stabilized Pickering emulsions were prepared, and lutein was encapsulated into corn oil droplets to increase its stability and bioavailability in gastrointestinal digestion. The interaction between Chlorella pyrenoidosa protein (CP) and chitosan (CS), and the effect of chitosan concentration on the emulsifying ability of the complex and emulsion stability were studied. With the increase of CS concentration from 0% to 0.8%, the emulsion droplet size obviously decreased, and the emulsion stability and viscosity increased significantly. In particular, when the concentration was 0.8%, the emulsion system was stable at 80 °C and 400 mM sodium chloride. After ultraviolet irradiation for 48 h, the retention rate of lutein encapsulated in Pickering emulsions was 54.33%, which was significantly higher than that (30.67%) of lutein dissolved in corn oil. The retention rate of lutein in Pickering emulsions stabilized by CP-CS complex was significantly higher than that in Pickering emulsions stabilized by CP only and corn oil after heating at 90 °C for 8 h. The results of simulated gastrointestinal digestion showed that the bioavailability of lutein encapsulated in Pickering emulsions stabilized by CP-CS complex reached 44.83%. These results explored the high-value utilization of Chlorella pyrenoidosa and provided new insights into the preparation of Pickering emulsions and the protection for lutein.