High-pressure Homogenization Research Articles

Impact of non-thermal modifications on the physicochemical properties and functionality of litchi pomace dietary fibre

Pomace is frequently underestimated as a complex by-product. High pressure homogenisation (HPH), enzymatic hydrolysis (EH) and high hydrostatic pressure (HHP) modifications are applied to improve the functional properties of litchi pomace insoluble dietary fibre (LPDF). The relationships between physicochemical properties and structural alterations and digestibility of LPDF are studied. The results showed that HPH, EH and HHP changed the LPDF's microstructure, causing it to develop more porous structures. Meanwhile, HPH modification exhibited a remarkable effect on LPDF's water holding (15.6 g/g), water swelling (26.1 mL/g) and oil retention (5.4 g/g) capabilities, resulting in the change of the complexity of the neutral sugar side chain. Notably, the highest total phenol content (3.4 GAE mg/g) and antioxidant activities (DPPH 153.6, ABTS 188.9, FRAP 195.1 μmol Trolox/g) were also observed in LPDF modified with HPH. Moreover, the diversity of structural features and high affinity of modified LPDFs are conducive to its functional properties, i.e., inhibition of starch digestion. The remarkable potential of LPDF modified with HPH was attributed to the beneficial effects of dietary fibre on human health. As a result, litchi pomace could be a useful and effective source of functional fibres. The incorporation of litchi pomace into the human diet is still underexplored but is a promising alternative.

Impact of high-pressure homogenisation of milk on physicochemical, microbiological, and textural characteristics of sheep milk yoghurt

Yoghurt samples were produced from sheep milk that was high-pressure homogenisation (HPH) treated at 0 (control), 30, 50, 70 and 100 MPa. Depending on the acidification kinetic parameters, HPH treatment increased the acidification rate and shortened the fermentation time. HPH-treated samples had lower pH, increased water holding capacity, decreased syneresis, decreased particle size and higher acetaldehyde content than the control. At 0 and 14 days of storage, the tyrosine value of HPH-treated samples was higher than the control. Although HPH resulted in higher L∗ and a∗ values, it caused lower b∗ values in yoghurt samples. Up to 30 MPa, HPH increased firmness and consistency; however, these were decreased above 50 MPa. During storage, Streptococcus thermophilus and Lactobacillus bulgaricus counts ranged from 6.12 to 8.20 log cfu g−1 and 5.70 to 8.96 log cfu g−1, respectively. Depending on the increasing pressure, HPH caused higher S. thermophilus and L. bulgaricus counts.

Heat-treated Pediococcus acidilactici LM1013-mediated inhibition of biofilm formation by Cutibacterium acnes and its application in acne vulgaris: A single-arm clinical trial.

Acne vulgaris is a common skin disease accompanied by chronic inflammation in the pilosebaceous follicles, resulting from excessive Cutibacterium acnes. This study aimed to investigate the inhibition of biofilm formation by C. acnes ATCC 6919 using heat-treated Pediococcus acidilactici LM1013 (HT-LM1013), previously isolated from the Korean traditional fermented alcoholic beverage-makgeolli, and its application as a leave-on-type product for patients with acne vulgaris. HT-LM1013 was prepared by Lactomason and homogenized using a high-pressure homogenizer. The minimum inhibitory concentration (MIC), tricarboxylic acid (TCA) cycle, and lipase activity were evaluated for C. acnes inhibition. Inhibition of biofilm formation was demonstrated using a crystal violet solution. Damaged C. acnes was observed using field-emission scanning electron microscopy (FE-SEM). Clinical trials were performed using a leave-on-type product containing HT-LM1013. HT-LM1013 inhibited the TCA cycle (36.80%) and lipase activity using palmitate (31.89%), stearate (36.91%), and oleate (30.86%) as substrates at 1 × MIC (p < 0.01). After treatment with HT-LM1013, concave and elongated shapes of C. acnes were observed by FE-SEM. In addition, HT-LM1013 inhibited biofilm formation by 71.75% at 1 × MIC (p < 0.001) and removed 73.35% of mature biofilms (p < 0.01). In the clinical trial, the leave-on-type product decreased the number of closed comedones from 14.04 to 10.22, open comedones from 7.22 to 4.39%, and sebum content to 76.23% at week 4 (p < 0.01). The satisfaction score of the participants was recorded 3.83 on a five-point scale. HT-LM1013 is potent for the treatment of acne vulgaris.

Addition of gelatin increased the spray drying performance of the Pickering emulsion stabilized by the ovalbumin – gum Arabic electrostatic complex

Gelatin was added to the perilla seed oil (PSO) Pickering emulsion stabilized by the ovalbumin (OVA) – gum Arabic (GA) electrostatic complex to increase its spray drying performance. The results indicated that the addition of gelatin to the primary PSO Pickering emulsion in mass ratio to the OVA – GA complex 1:1 before high-pressure homogenization could increase the total solid concentration of the feed to 20% and decrease the surface oil content of the resultant powder to 9.90% without compromising its total oil content (77.84%) and powder yield (76.08%) compared with that in the absence of gelatin. Characterization of the Pickering emulsions revealed that gelatin adsorbed to the surface of the primary emulsion droplets through electrostatic interaction and the subsequent high-pressure homogenization caused composition and structure rearrangement in the emulsion interface, leading to reduced particle size and viscosity of the secondary emulsion. The optimized PSO powder possessed excellent structural integrity according to scanning electron microscope observation as well as good flowability and water dispersibility. Hence, the addition of gelatin is an effective strategy to improve the economy for producing powders with ultra-high oil contents by spray drying Pickering emulsions stabilized by the OVA – GA electrostatic complex.

Formulation and Characteristics of Nanostuctured Lipid Carrier (NLC) Red Palm Oil (RPO) Prepared by High-Pressure Homogenization and Its Applications in Orange Juice

A Nanostructured lipid carrier (NLC) is an emulsion system that can encapsulate and improve stability of lipid-based bioactive compounds. This study aimed to develop an optimal RPO-NLC formula with a combination of solid and liquid lipids, lipids and surfactants, and the use of high-pressure homogenizer (HPH). RPO-NLC was made using HPH with a 400 bar and 600 bar pressure. A Completely randomized design (CRD) with three factors was used to determine interactions between factors. The RPO-NLC formula was characterized based on particle size. One of the best formulas was selected with small particle size and high RPO content then characterized based on encapsulation efficiency (EE), loading capacity (LC), storage stability, FTIR, thermal and applied to orange juice including sensory evaluation, encapsulation stability and pH. RPO-NLC yielded particle size 44.9 nm, EE 99.9±0.02%, LC 4.9±0.001%, was stable on storage. β-carotene identified in RPO-NLC lipid matrix based on FTIR analysis and has good thermal stability based on differential scanning calorimeter analysis. Sensory evaluation showed changes in sensory attributes of color, aroma, taste during storage. Encapsulation stability showed significant increase during storage and pH measurement results also increased.

Nanoemulsion Loaded with Clotrimazole Based on Rapeseed Oil for Potential Vaginal Application-Development, Initial Assessment, and Pilot Release Studies.

Vaginal candidiasis (VC) is an emerging global hardly treated health issue affecting millions of women worldwide. In this study, the nanoemulsion consisting of clotrimazole (CLT), rapeseed oil, Pluronic F-68, Span 80, PEG 200, and lactic acid was prepared using high-speed and high-pressure homogenization. Yielded formulations were characterized by an average droplet size of 52-56 nm, homogenous size distribution by volume, and a polydispersity index (PDI) < 0.2. The osmolality of nanoemulsions (NEs) fulfilled the recommendations of the WHO advisory note. NEs were stable throughout 28 weeks of storage. The stationary and dynamic (USP apparatus IV) pilot study of the changes of free CLT over time for NEs, as well as market cream and CLT suspension as references, were conducted. Test results of the changes in the amount of free CLT released from the encapsulated form were not coherent; in the stationary method, NEs yielded up to 27% of the released CLT dose within 5 h, while in the USP apparatus IV method, NEs released up to 10% of the CLT dose. NEs are promising carriers for vaginal drug delivery in the treatment of VC; however, further development of the final dosage form and harmonized release or dissolution testing protocols are needed.

NANOSUSPENSIONS: A STRATERGY TO INCREASE THE SOLUBILITY AND BIOAVAILABILITY OF POORLY WATER-SOLUBLE DRUGS

The process that occurs at the molecular level and at the nanoscale is the subject of nanotechnology. Nanotechnology includes nanosuspension. Nanosuspension is a colloidal dispersion of medication particles that are nanometer-sized and stabilized with surfactants. To manufacture and scale up nanosuspensions, conventional size reduction tools such as media mills and high-pressure homogenizers as well as formulation strategies including precipitation, emulsion-solvent evaporation, solvent diffusion, and microemulsion procedures can be successfully used. The main elements to be taken into consideration for the effective manufacture and scale-up of nanosuspensions are maintaining the stability in solution as well as in the solid form, and resuspendability without aggregation. The flexibility for surface modification and mucoadhesion for drug targeting have substantially broadened the scope of this innovative formulation method as a result of the significant improvement in bioavailability. Extensive research is now being done on the use of nanosuspensions in various drug delivery methods, including oral, ophthalmic, brain, topical, buccal, nasal, and transdermal routes. The majority of permeability limiting absorption and hepatic first-pass metabolism associated difficulties that negatively affect bioavailability can be resolved with oral drug delivery of nanosuspension with receptor mediated endocytosis, which is a promising capability. The development of enabling technologies like nanosuspension can address several formulation issues that protein- and peptide-based medicines currently encounter

Potential of redcurrant protein-enriched fractions as emulsifier in oil–water-emulsions

Berry protein, due to its functional properties, was extracted from redcurrant pomace seeds (RPS) in aqueous media to utilise side-streams and increase the sustainability of food production. Emulsions containing 1% redcurrant seed protein and 10% rapeseed oil were prepared by high pressure homogenisation. The emulsions’ structure, droplet surface charge, stability, rheological behaviour, and colour were characterised by microscopy, dynamic laser light scattering, storage tests and bulk rheology including large amplitude oscillatory shear rheology, respectively. Protein extracts of RPS proved to stabilise oil–water-interfaces by formation of a protein film having non-linear flow characteristics. While at low to medium shear, the emulsions showed pseudoplastic behaviour, limited molecular mobility at the interface induced softening at high shear. The shear stability of the interfacial protein layer decreased with increasing pH, i.e. with increasing molecular charge. Emulsions were prone to flocculation and subsequent creaming, either because of low surface charge at low pH or due to bridging by proteins and polymerised polyphenol complexes under neutral conditions. Although redcurrants only occupy a small market share in the berry sector, they are of high importance for specialised local producers and results presented here might evince possibilities for the utilisation of other pomace types.

Evaluation of cell disruption technologies on magnetosome chain length and aggregation behaviour from Magnetospirillum gryphiswaldense MSR-1.

Magnetosomes are biologically-derived magnetic nanoparticles (MNPs) naturally produced by magnetotactic bacteria (MTB). Due to their distinctive characteristics, such as narrow size distribution and high biocompatibility, magnetosomes represent an attractive alternative to existing commercially-available chemically-synthesized MNPs. However, to extract magnetosomes from the bacteria, a cell disruption step is required. In this study, a systematic comparison between three disruption techniques (enzymatic treatment, probe sonication and high-pressure homogenization) was carried out to study their effect on the chain length, integrity and aggregation state of magnetosomes isolated from Magnetospirillum gryphiswaldense MSR-1 cells. Experimental results revealed that all three methodologies show high cell disruption yields (>89%). Transmission electron microscopy (TEM), dynamic light scattering (DLS) and, for the first time, nano-flow cytometry (nFCM) were employed to characterize magnetosome preparations after purification. TEM and DLS showed that high-pressure homogenization resulted in optimal conservation of chain integrity, whereas enzymatic treatment caused higher chain cleavage. The data obtained suggest that nFCM is best suited to characterize single membrane-wrapped magnetosomes, which can be particularly useful for applications that require the use of individual magnetosomes. Magnetosomes were also successfully labelled (>90%) with the fluorescent CellMask™ Deep Red membrane stain and analysed by nFCM, demonstrating the promising capacity of this technique as a rapid analytical tool for magnetosome quality assurance. The results of this work contribute to the future development of a robust magnetosome production platform.

High-pressure homogenization treatment of red seaweed Bangia fusco-purpurea affects the physicochemical, functional properties and enhances in vitro anti-glycation activity of its dietary fibers

In this study, high-pressure homogenization (HPH) technique was applied for the pretreatment of Bangia fusco-purpurea, and the effect of HPH on the composition, physiochemical and functional properties, and in vitro anti-glycation activity of dietary fiber from this seaweed (B. fusco-purpurea dietary fiber, BDF) was studied. Results showed that HPH significantly increased water-soluble dietary fiber (SDF) content in BDF. Water-holding capacity, oil-holding capacity, and glucose delay dialysis index of BDF were significantly enhanced after HPH treatment. Additionally, HPH significantly improved the in vitro anti-glycation activity of BDF by inhibiting the formation of advanced glycation end products (AGEs) and mitigating damage induced by AGEs on intestinal cells. These improvements could be attributed to the formation of the coarse and porous structure and greater exposure of hydroxyl groups of BDF caused by HPH treatment. These results implied the potential of HPH in seaweed processing and provided a scientific basis for the in-depth, comprehensive utilization of B. fusco-purpurea. Industrial relevanceHPH is an emerging non-thermal food processing technique with promising application potential in food industry. In this study, we found that HPH technique could significantly change the composition, improve physiochemical and functional properties and enhance anti-glycation activity of dietary fiber from seaweed B. fusco-purpurea. Our results validated the efficiency of HPH on dietary fiber modification, implying the potential of HPH in food industry and healthy industry.

Innovative system based on natural polyelectrolyte complex and cellulose micro/nanofibers to improve drainability and properties of recycled paper

In this work, the efficiency of a polyelectrolyte complex (PEC) to retain different cellulose micro/nanofibers (CMNFs) during paper formation and to improve the physical properties of recycled unbleached fiber paper was analyzed. CMNFs were obtained from a commercial bleached eucalyptus pulp (BEP) using a PFI refiner followed by a chemical treatment with oxalic acid at two different concentrations. Finally, the pulp was fibrillated using a high-pressure homogenizer at three different intensities. The PEC was formed by addition of the xylan (Xyl) solution on chitosan (CH) solution with a Xyl/CH mass ratio of 80/20. The required dosages of PEC solution to neutralize the charges of different nanocellulose fractions were determined by ζ-potential measurements, and the CMNF retentions on recycled unbleached fibers were evaluated in a Britt Dynamic Drainage Jar. The results showed that the maximum retention was obtained when the neutral PEC-CMNF system was added to pulp. Besides, a significant decrease on °SR was observed when PEC and PEC-CMNF systems were added to the untreated pulp, limiting the negative effects of nanocellulose addition on pulp drainability. The incorporation of PEC-CMNF systems to the handsheets increased the tensile index (up to 28%), Mullen index (up to 40%) and internal bonding (up to 255%). Finally, the compressive strength of the handsheets, namely SCT and CMT, increased up to 30 and 70%, respectively. These simultaneous improvement on drainability and mechanical properties makes the proposed PEC-CMNF system a promising solution for the production of packaging paper.

Nano-Emulsion Based Gel for Topical Delivery of an Anti-Inflammatory Drug: In vitro and in vivo Evaluation.

Arthritic disorder is a common disease in elderly patients and the most common cause of joint dysfunction. This study aims to design Piroxicam-loaded nanoemulsion (PXM-NE) formulations to enhance the analgesic and anti-inflammatory activity of the drug for topical use. The nanoemulsion preparations were designed based on a high-pressure homogenization technique and were characterized for particle size (PS), poly dispersity index (Pi), zeta potential (ZP), drug content, and the selected formula was investigated for its topical analgesic activity and pharmacokinetic parameters. The characterizations showed that the PS was 310.20±19.84 nm, Pi was 0.15±0.02, and ZP was -15.74±1.6 mV for the selected formula. A morphology study showed that the PXM-NE droplets were spherical with a uniform size distribution. The in vitro release study showed a biphasic release pattern with a rapid release within the first 2 hours followed by a sustained release pattern. The analgesic activity for optimal formula was 1.66 times higher than the commercial gel with a double duration of analgesic activity. The Cmax was 45.73±9.95 and 28.48±6.44 ng/mL for the gel form of the selected formula and the commercial gel respectively. The relevant bioavailability of the selected formula was 2.41 higher than the commercial gel. The results showed good physicochemical properties, higher bioavailability, and a longer analgesic effect of PXM from nanoemulsion gel, as compared to the commercial product.

Formation and characterization of oleogels derived from emulsions: Evaluation of polysaccharide ratio and emulsification method

In the present work, highly oil-binding oleogels were fabricated by two polysaccharides (insoluble soybean fiber (ISF) and hydroxypropyl methylcellulose (HPMC)) using an emulsion-templated method. The polysaccharide-based network was developed by oven-drying ISF and HPMC co-stabilized emulsions to obtain the oleogels and two emulsification methods were compared. The aqueous polysaccharide mixtures displayed an increased hydrodynamic diameter but decreased viscosity with increasing proportions of ISF, leading to a reduced interfacial tension. Increased HPMC reduced the droplet size of emulsions while it improved the apparent viscosity and loss modulus. Emulsions prepared by high-pressure homogenization displayed a smaller droplet size and lower viscosity while the oleogels exhibited abundant liquid oil. By contrast, emulsions prepared by high-speed shearing presented a larger droplet size while the oleogels exhibited well-structured semi-solid oil. The oleogels were endowed with stronger gel strength (increased to 184 g and 461 g, respectively) and hardness from increased HPMC, resulting in a decreased oil loss. Increasing the HPMC content contributed to a more compact structure of the oleogels and emulsions whereby emulsions with a too small droplet size were difficult to be fully converted into gel-like semi-solid oil. Results indicate that ISF and HPMC can be applied in structuring oleogels as substitutes for solid fats.

Food Emulsion Gels from Plant-Based Ingredients: Formulation, Processing, and Potential Applications.

Recent advances in the understanding of formulations and processing techniques have allowed for greater freedom in plant-based emulsion gel design to better recreate conventional animal-based foods. The roles of plant-based proteins, polysaccharides, and lipids in the formulation of emulsion gels and relevant processing techniques such as high-pressure homogenization (HPH), ultrasound (UH), and microfluidization (MF), were discussed in correlation with the effects of varying HPH, UH, and MF processing parameters on emulsion gel properties. The characterization methods for plant-based emulsion gels to quantify their rheological, thermal, and textural properties, as well as gel microstructure, were presented with a focus on how they can be applied for food purposes. Finally, the potential applications of plant-based emulsion gels, such as dairy and meat alternatives, condiments, baked goods, and functional foods, were discussed with a focus on sensory properties and consumer acceptance. This study found that the implementation of plant-based emulsion gel in food is promising to date despite persisting challenges. This review will provide valuable insights for researchers and industry professionals looking to understand and utilize plant-based food emulsion gels.

Isolation of cellulose microfibers and nanofibers by mechanical fibrillation in a water-free solvent

Cellulose from vegetable sources is the most abundant biopolymer on earth. In plants, cellulose is a reinforcement element that conforms to a hierarchical structure. Cellulose micro-/nanofibers can be isolated from the cell wall by top-down strategies involving mechanical processes to be used in applications as a reinforcing material. Nonetheless, its use has been limited as its extraction in an aqueous medium is unfavorable when employed in low-hydrophilic matrices. Therefore, this work proposes a novel homogenization route in which cellulose micro-/nanofibers are directly obtained and dispersed in propylene glycol (PG), which generates more possibilities for these (nano) structures in applications that require water-free environments. Moreover, the influence on the cycle numbers in the morphological, chemical, thermal, and rheological properties was researched. Thus, the obtained micro-/nanofibers presented TEM diameters even below 20 nm. XRD analysis evidenced crystalline planes located at 1overline{1 }0, 110, and 200, and crystallinity degree values up to 80%. Also, FTIR spectra bands in 3340 cm−1, 2890 cm−1, 1314 cm−1, and in the fingerprint region corresponded to native cellulose Iβ. FTIR and TGA confirmed no influence of mechanical cycles on cellulose fibers’ chemical and thermal properties. Furthermore, the increase in the cycle number evidenced a shear-thinning rheological behavior of the suspensions. Considering the above results, it was concluded that the proposed high-pressure homogenization within PG is an approach for vegetable nanocellulose homogenization while maintaining high crystallinity, thermal, and chemical features with huge importance for subsequent processes in the development of nanocomposites with hydrophilic matrices for industrial applications.Graphical abstract

Nanotechnology Applied to Cellulosic Materials.

In recent years, nanocellulosic materials have attracted special attention because of their performance in different advanced applications, biodegradability, availability, and biocompatibility. Nanocellulosic materials can assume three distinct morphologies, including cellulose nanocrystals (CNC), cellulose nanofibers (CNF), and bacterial cellulose (BC). This review consists of two main parts related to obtaining and applying nanocelluloses in advanced materials. In the first part, the mechanical, chemical, and enzymatic treatments necessary for the production of nanocelluloses are discussed. Among chemical pretreatments, the most common approaches are described, such as acid- and alkali-catalyzed organosolvation, 2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO)-mediated oxidation, ammonium persulfate (APS) and sodium persulfate (SPS) oxidative treatments, ozone, extraction with ionic liquids, and acid hydrolysis. As for mechanical/physical treatments, methods reviewed include refining, high-pressure homogenization, microfluidization, grinding, cryogenic crushing, steam blasting, ultrasound, extrusion, aqueous counter collision, and electrospinning. The application of nanocellulose focused, in particular, on triboelectric nanogenerators (TENGs) with CNC, CNF, and BC. With the development of TENGs, an unparalleled revolution is expected; there will be self-powered sensors, wearable and implantable electronic components, and a series of other innovative applications. In the future new era of TENGs, nanocellulose will certainly be a promising material in their constitution.

Impact of bacterial cellulose on the physical properties and printing quality of fine papers

Bacterial nanocellulose (BNC), due to its inherent nanometric scale and strength properties, can be considered as a good candidate to be used in papermaking. This work explored the possibility of using it in the production of fine paper as a wet-end component and for the paper coating. Filler-containing handsheet production was performed with and without the presence of common additives typically used in the furnish of office papers. It was found that, under optimized conditions, BNC mechanically treated by high-pressure homogenization could improve all the evaluated paper properties (mechanical, optical and structural) without impairing the filler retention. However, paper strength was improved only to a small extent (increase in the tensile index of 8 % for a filler content of ca. 27.5 %). On the other hand, when used at the paper surface, remarkable improvements in the gamut area of >25 % in comparison to the base paper and of >40 % in comparison to starch-only coated papers were achieved for a formulation having 50 % BNC and 50 % of carboxymethylcellulose. Overall, the present results highlight the possibility of using BNC as a paper component, particularly when applied at the paper substrate as a coating agent aiming at improving printing quality.

The impact of apple destructuring and thermal treatment on bioactive compounds: the fate of dietary fibre and polyphenols in puree and homogenate

SummaryThe present study aimed at understanding the response of dietary fibres and phenolic compounds to apple matrix disintegration and thermal treatment. Apple was processed by mimicking industrial operations of blanching, destructuring by high‐speed homogenisation (HSH) or high‐pressure homogenisation (HPH), and pasteurisation. A viscous puree (0.73 Pa × s), made of juice embedding intact cells and large cell clusters, was obtained by HSH. Conversely, HPH completely disrupted apple tissue leading to a fluid homogenate (0.27 Pa × s) in which the fibrous matrix was suspended. Despite these differences, apple puree and homogenate presented similar content of total and soluble dietary fibre, with no significant differences in the chemical structure of apple pectin, as demonstrated by FT‐IR and NMR analyses. Apple puree and homogenate retained more than 80% of the phenolic content originally present in apple pulp (about 2125 mg/gdw) without detriment to radical scavenging activity. This minor phenolic depletion, regardless of the different extent of mechanical disintegration, was mainly due to the decrease of thermolabile flavanols upon application of analogous heat treatments.

Astaxanthin encapsulation in nanocapsule by high-pressure homogenization technology: a study on stability, antioxidant activity and in vitro release

The astaxanthin nanocapsules (ASX-LNC) was prepared by high-pressure homogenization technology, the microstructure, stability, antioxidant activity, and in vitro release characteristics of ASX-LNC were characterized and evaluated. The ASX-LNC comprised a core material and wall materials. The core material was composed of astaxanthin oil, and the wall materials were composed of β-cyclodextrin, decapolyglycerol monooleate, soybean lecithin (PC60), glycerol, and deionized water. The mean particle size of the ASX-LNC was 206.9 ± 2.8 nm, and the polydispersity index (PdI) value was 0.218 ± 0.026. The zeta potential of ASX-LNC was −26.16 ± 0.87 mV. The loading amount of ASX-LNC was 0.546%±0.032%, and the encapsulation efficiency was 99.65%±0.13%, indicating that the preparation process was feasible. The stability of ASX-LNC was determined under different conditions, indicating good stability of the ASX-LNC. In antioxidant research, the inhibition rate of free radicals of ASX-LNC was 91.03 ± 0.87% under 250 μg/mL for 30 min, and the inhibition rate of free radicals of astaxanthin ethanol solution was 90.83 ± 1.37%. The antioxidant capacity of astaxanthin was not affected by the encapsulation, which demonstrated the effect of prolonging the release of active ingredients due to the protection of the biological activity of astaxanthin by encapsulation. Compared with the astaxanthin ethanol solution, the ASX-LNC had a slow-release effect and could prolong the action time of active substances. Overall, ASX-LNC is a potential carrier for application in food and health products, which can control the release of active substances.

Characterization and antivibrio activity of chitosan-citral Schiff base calcium complex for a calcium citrate sustained release antibacterial agent

Vibrio parahemolyticus is the “Number one killer” of seafood products. Anti-vibrio agents having low cost and high-safety are urgently needed to supplement the application needs. This work attempted to prepare CS-CT-CCa complex with citral (CT), chitosan (CS) and calcium citrate (CCa) as raw material by microwave-assisted high-pressure homogenization. Additionally the coordination structure and morphology of Bridge-CS-CT-Schiff base/OH-CCa were verified. The prepared CS-CT-CCa had a well-dispersed property (the size: 3.55~9.33 μm and the zeta potential: +38.7~+67.5 mV) and an excellent sustained released ability (sustained release up to 180 min). MIC, Glucose assay, MDA assay, biofilm formation inhibition assay, SEM, swimming and swarming motility assay demonstrated that CS-CT-CCa had strong (MIC of 128 μg/mL) and sustained (more than 12 h) inhibitory effects against V. parahaemolyticus. Meanwhile, CS-CT-CCa could increase the membrane permeability of V. parahaemolyticus and inhibit their biofilm-forming ability in a dose-dependent manner. It could be inferred that the antibacterial activities against V. parahaemolyticus caused inhibition of biofilm formation, swimming and swarming motilities. This study provided necessary data for the further design and development of chitosan antibacterial agents, food and feed additives.