Investigation on complex coacervation between fish skin gelatin from cold-water fish and gum arabic: Phase behavior, thermodynamic, and structural properties

Effect of Microsphere Concentration on Catechin Release from Microneedle Arrays

In this work, microspheres were developed by cross-linking glutaraldehyde in an aqueous gelatin solution with a surfactant and solvent. A poly(vinyl alcohol) (PVA) solution was produced and combined with catechin-loaded microspheres. Different microsphere concentrations (0%, 5%, 10%, and 15%) were applied to the PVA microneedles. The moisture content, particle size, swelling, and drug release percentage of microneedles were studied using various microsphere concentrations. Fourier transform infrared and scanning electron microscopy (SEM) investigations validated the structure of gelatin microspheres as well as their decoration in microneedles. The SEM scans revealed that spherical microspheres with a wrinkled and folded morphology were created, with no physical holes visible on the surface. The gelatin microspheres generated had a mean particle size of 20-30 μm. Ex vivo release analysis indicated that microneedles containing 10% microspheres released the most catechin, with 42.9% at 12 h and 84.4% at 24 h.

Extracellular Matrix-Mimetic Intrinsic Versatile Coating Derived from Marine Adhesive Protein Promotes Diabetic Wound Healing through Regulating the Microenvironment

The management of diabetic wound healing remains a severe clinical challenge due to the complicated wound microenvironments, including abnormal immune regulation, excessive reactive oxygen species (ROS), and repeated bacterial infections. Herein, we report an extracellular matrix (ECM)-mimetic coating derived from scallop byssal protein (Sbp9Δ), which can be assembled in situ within 30 min under the trigger of Ca2+ driven by strong coordination interaction. The biocompatible Sbp9Δ coating and genetically programmable LL37-fused coating exhibit outstanding antioxidant, antibacterial, and immune regulatory properties in vitro. Proof-of-concept applications demonstrate that the coating can reliably promote wound healing in animal models, including diabetic mice and rabbits, ex vivo human skins, and Staphylococcus aureus-infected diabetic mice. In-depth mechanism investigation indicates that improved wound microenvironments accelerated wound repair, including alleviated bacterial infection, lessened inflammation, appearance of abundant M2-type macrophages, removal of ROS, promoted angiogenesis, and re-epithelialization. Collectively, our investigation provides an in situ, convenient, and effective approach for diabetic wound repair.

Analysis of non-covalent interaction between β-lactoglobulin and hyaluronic acid under ultrasound-assisted treatment: Conformational structures and interfacial properties

Hyaluronic acid (HA) used as a food ingredient is gaining acceptance and popularity. However, the studies available for the effect of HA concentrations on the properties of β-lactoglobulin (β-LG) were limited. In this study, we investigated that the molecular characterization and functional properties of the complex formed by the non-covalent binding of β-LG and HA, as well as the ultrasound-assisted treatment at acidic pH. The optimal pH and ratio of β-LG/HA were set as 7 and 4:1, respectively. The fluorescence spectroscopy, circular dichroism spectroscopy, and molecular docking results revealed that the addition of HA and ultrasound induced a decrease in random coil and α-helix and an increase in β-sheet contents in β-LG. By the complexation with HA, the thermal stability, freezing stability, and antioxidant properties of β-LG were all improved under ultrasound treatment. The results of the present study can be useful for the modulation of HA based biopolymer complexes and the exploitation as encapsulating or structuring agents in food industry.

Interaction mechanisms of peanut protein isolate and high methoxyl pectin with ultrasound treatment: The effect of ultrasound parameters, biopolymer ratio, and pH

Ultrasound could effectively change molecular structure of proteins, polysaccharides, and their interactions, and was used to treat the peanut protein isolate-high methoxy pectin (PPI-HMP) complexes in this study. Effects of different ultrasound parameters, PPI-HMP mixing ratio (40:1-5:2), and pH (2.0-8.0) on the PPI-HMP interactions were investigated. Turbidity, solution appearance, and Zeta-potential analysis revealed an electrostatic interaction between PPI and HMP from pH 2.0 to pH 6.0. Ultrasound changed the tertiary structure conformation of PPI according to the surface hydrophobicity analysis. Increased ultrasound power density and pH broke the hydrogen bonds between the complexes according to Fourier transform infrared spectroscopy analysis. Apparent viscosity and confocal laser scanning microscopy analysis showed that appropriate ultrasound treatment (5.43 W/cm3, 25 min, 25 °C) reduced the viscosity of the complexes, and enhanced the electrostatic and hydrophobic interactions between PPI and HMP. These findings will contribute to the application of PPI-HMP complexes in the food industry.

pH-induced complex coacervation of fish gelatin and carboxylated chitosan: phase behavior and structural properties

The aim of this study was to investigate the phase behavior and structural properties of fish gelatin complex coacervation with carboxylated chitosan as a function of pH by varying the amount of carboxylated chitosan added (0-0.25%, w/v) while keeping the fish gelatin concentration constant at 0.667% (w/v). Zeta potential indicated that electrostatic interaction drove the complex coalescence of fish gelatin and carboxylated chitosan to form soluble or insoluble complexes. The turbidity of the fish gelatin-carboxylated chitosan complex system was greatest at a carboxylated chitosan concentration of 0.2%. UV and fluorescence spectroscopy indicated that the carboxylated chitosan changed the tertiary conformation of fish gelatin. Circular dichroism showed that complexation of fish gelatin with carboxylated chitosan resulted in a shift from the α-helix to the β-sheet structure of fish gelatin. In particular, at pH 5, the fish gelatin complexed with carboxylated chitosan had a disordered structure. X-ray diffraction and scanning electron microscopy of the composite coacervates both investigated that electrostatic interaction between the two replaced molecular interaction within the carboxylated chitosan to form a new lamellar porous structure. These findings may in future enable the use of fish gelatin-carboxylated chitosan complex systems in the design of new food matrices.

Application of Poultry Gelatin to Enhance the Physicochemical, Mechanical, and Rheological Properties of Fish Gelatin as Alternative Mammalian Gelatin Films for Food Packaging

This study aimed to describe the properties of cold water fish gelatin (FG) blended with poultry gelatin (PG) for a production of a sachet containing olive oil. To find a desirable film, the different ratio of FG-PG-based films were characterized in terms of mechanical properties. As the proportion of PG in PG-FG-based increased, the tensile strength and Young's modulus were increased, and the elongation at break and heat seal strength of the films were decreased. The 50-50 film had favorable characteristics to use as a sachet. The amount of acid index and peroxide of the oil stored in the sachets after 14 days showed that there is a significant difference (p < 0.05) between the films. The barrier properties of the films including the water vapor permeability and oxygen permeability of films were increased from 1.21 to 4.95 × 10^-11 g m^-1 Pa^-1 s^-1 and 48 to 97 cm³ mµ/m² d kPa, respectively. Dark, red, yellow, and opaque films were realized with increasing PG. Fourier transform infrared (FTIR) spectra approved a wide peak of approximately 2500 cm^-1. The rheological analysis indicated that, by adding PG, viscosity, elastic modulus (G') and loss modulus (G'') were increased significantly (p < 0.05) about 9.5, 9.32 and 18 times, respectively. Therefore, an easy modification of FG with PG will make it suitable for oil sachet packaging applications for the food industry.

Manuka Honey/2-Hydroxyethyl Methacrylate/Gelatin Hybrid Hydrogel Scaffolds for Potential Tissue Regeneration

Scaffolding biomaterials are gaining great importance due to their beneficial properties for medical purposes. Targeted biomaterial engineering strategies through the synergy of different material types can be applied to design hybrid scaffolding biomaterials with advantageous properties for biomedical applications. In our research, a novel combination of the bioactive agent Manuka honey (MHo) with 2-hydroxyethyl methacrylate/gelatin (HG) hydrogel scaffolds was created as an efficient bioactive platform for biomedical applications. The effects of Manuka honey content on structural characteristics, porosity, swelling performance, in vitro degradation, and in vitro biocompatibility (fibroblast and keratinocyte cell lines) of hybrid hydrogel scaffolds were studied using Fourier transform infrared spectroscopy, the gravimetric method, and in vitro MTT biocompatibility assays. The engineered hybrid hydrogel scaffolds show advantageous properties, including porosity in the range of 71.25% to 90.09%, specific pH- and temperature-dependent swelling performance, and convenient absorption capacity. In vitro degradation studies showed scaffold degradability ranging from 6.27% to 27.18% for four weeks. In vitro biocompatibility assays on healthy human fibroblast (MRC5 cells) and keratinocyte (HaCaT cells) cell lines by MTT tests showed that cell viability depends on the Manuka honey content loaded in the HG hydrogel scaffolds. A sample containing the highest Manuka honey content (30%) exhibited the best biocompatible properties. The obtained results reveal that the synergy of the bioactive agent, Manuka honey, with 2-hydroxyethyl methacrylate/gelatin as hybrid hydrogel scaffolds has potential for biomedical purposes. By tuning the Manuka honey content in HG hydrogel scaffolds advantageous properties of hybrid scaffolds can be achieved for biomedical applications.

An ameliorated anti-hTNF-α therapy for arthritis via carrier-free macromolecular nanoparticles consisted of infliximab

Infliximab (INF) is intravenously used for the clinical treatment of rheumatoid arthritis. However, it can cause serious side effects, which are mainly associated with systemic exposure and high doses. Here, we developed a modified hydrophobic ion-pairing complexes (INF HIPC) through the sequential introduction of bovine lactoferrin (BLF) and hyaluronic acid (HA) with opposite charges into the INF solution. INF and BLF were found to be not only integrally responsible for the structural integrity of HIPC but also were determined to have respective biological activities by binding human tumor necrosis factor-alpha (hTNF-α) or promoting the proliferation of osteoblasts. The INF HIPC had good stability, high drug-loading efficiency, and long-term retention effects. Whether via knee joint injection or intravenous injection, INF HIPC resulted in lower hTNF-α levels and less cartilage destruction than INFs in the transgenic mouse model. At the same time, INF HIPC could reduce toxicity based on body weight changes in transgenic mice. Our findings provide a simple and promising avenue to develop advanced delivery systems for other antibodies and macromolecules.

Coacervation as a Novel Method of Microencapsulation of Essential Oils-A Review

These days, consumers are increasingly "nutritionally aware". The trend of "clean label" is gaining momentum. Synthetic additives and preservatives, as well as natural ones, bearing the E symbol are more often perceived negatively. For this reason, substances of natural origin are sought tfor replacing them. Essential oils can be such substances. However, the wider use of essential oils in the food industry is severely limited. This is because these substances are highly sensitive to light, oxygen, and temperature. This creates problems with their processing and storage. In addition, they have a strong smell and taste, which makes them unacceptable when added to the product. The solution to this situation seems to be microencapsulation through complex coacervation. To reduce the loss of essential oils and the undesirable chemical changes that may occur during their spray drying-the most commonly used method-complex coacervation seems to be an interesting alternative. This article collects information on the limitations of the use of essential oils in food and proposes a solution through complex coacervation with plant proteins and chia mucilage.

Bioactive Interpenetrating Hydrogel Networks Based on 2-Hydroxyethyl Methacrylate and Gelatin Intertwined with Alginate and Dopped with Apatite as Scaffolding Biomaterials

Our goal was to create bioimitated scaffolding materials for biomedical purposes. The guiding idea was that we used an interpenetrating structural hierarchy of natural extracellular matrix as a “pattern” to design hydrogel scaffolds that show favorable properties for tissue regeneration. Polymeric hydrogel scaffolds are made in a simple, environmentally friendly way without additional functionalization. Gelatin and 2-hydroxyethyl methacrylate were selected to prepare interpenetrating polymeric networks and linear alginate chains were added as an interpenetrant to study their influence on the scaffold’s functionalities. Cryogelation and porogenation methods were used to obtain the designed scaffolding biomaterials. The scaffold’s structural, morphological, and mechanical properties, in vitro degradation, and cell viability properties were assessed to study the effects of the preparation method and alginate loading. Apatite as an inorganic agent was incorporated into cryogelated scaffolds to perform an extensive biological assay. Cryogelated scaffolds possess superior functionalities essential for tissue regeneration: fully hydrophilicity, degradability and mechanical features (2.08–9.75 MPa), and an optimal LDH activity. Furthermore, cryogelated scaffolds loaded with apatite showed good cell adhesion capacity, biocompatibility, and non-toxic behavior. All scaffolds performed equally in terms of metabolic activity and osteoconductivity. Cryogelated scaffolds with/without HAp could represent a new advance to promote osteoconductivity and enhance hard tissue repair. The obtained series of scaffolding biomaterials described here can provide a wide range of potential applications in the area of biomedical engineering.

Complexation of fish skin gelatin with glutentin and its effect on the properties of wheat dough and bread

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A complex of fishskin gelatin and glutenin was formed in dough.

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Gelatin enhanced the strength and gas-retention capacity of dough.

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Gelatin improved the porosity and cell size of crumb and the specific volume of bread.

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Gelatin retarded the firming rate of crumb and starch retrogradation.

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Gelatin inhibited water diffusion from marginal crumb to crust.

This study aimed to investigate the effect of fish skin gelatin (Gadus morhua, 0.5%, or 1.0%, flour basis) on the properties of wheat (Triticum aestivum) dough and bread. Compared with the control group, the addition of 1.0% gelatin increased the storage modulus and the maximum resistance of dough, resulting in a longer rupture time and a larger final gas-retention volume of the dough. Bread characteristics showed that the specific loaf volume and crumb cell size both increased. Molecular dynamics simulation indicated that gelatin and glutenin segments formed a complex, where a large amount of hydroxyl groups on the surface retarded water mobility in bread. Gelatin-glutentin complexes with the high water-holding capacity inhibited water diffusion from marginal crumb to crust, and decreased starch retrogradation enthalpy and firming rate of crumb. Thus, fish skin gelatin might be a good improver of wheat dough and bread.

Production, Processing, and Protection of Microalgal n-3 PUFA-Rich Oil

Microalgae have been increasingly considered as a sustainable “biofactory” with huge potentials to fill up the current and future shortages of food and nutrition. They have become an economically and technologically viable solution to produce a great diversity of high-value bioactive compounds, including n-3 polyunsaturated fatty acids (PUFA). The n-3 PUFA, especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), possess an array of biological activities and positively affect a number of diseases, including cardiovascular and neurodegenerative disorders. As such, the global market of n-3 PUFA has been increasing at a fast pace in the past two decades. Nowadays, the supply of n-3 PUFA is facing serious challenges as a result of global warming and maximal/over marine fisheries catches. Although increasing rapidly in recent years, aquaculture as an alternative source of n-3 PUFA appears insufficient to meet the fast increase in consumption and market demand. Therefore, the cultivation of microalgae stands out as a potential solution to meet the shortages of the n-3 PUFA market and provides unique fatty acids for the special groups of the population. This review focuses on the biosynthesis pathways and recombinant engineering approaches that can be used to enhance the production of n-3 PUFA, the impact of environmental conditions in heterotrophic cultivation on n-3 PUFA production, and the technologies that have been applied in the food industry to extract and purify oil in microalgae and protect n-3 PUFA from oxidation.

Maillard-Type Protein-Polysaccharide Conjugates and Electrostatic Protein-Polysaccharide Complexes as Delivery Vehicles for Food Bioactive Ingredients: Formation, Types, and Applications

Due to their combination of featured properties, protein and polysaccharide-based carriers show promising potential in food bioactive ingredient encapsulation, protection, and delivery. The formation of protein–polysaccharide complexes and conjugates involves non-covalent interactions and covalent interaction, respectively. The common types of protein–polysaccharide complex/conjugate-based bioactive ingredient delivery systems include emulsion (conventional emulsion, nanoemulsion, multiple emulsion, multilayered emulsion, and Pickering emulsion), microcapsule, hydrogel, and nanoparticle-based delivery systems. This review highlights the applications of protein–polysaccharide-based delivery vehicles in common bioactive ingredients including polyphenols, food proteins, bioactive peptides, carotenoids, vitamins, and minerals. The loaded food bioactive ingredients exhibited enhanced physicochemical stability, bioaccessibility, and sustained release in simulated gastrointestinal digestion. However, limited research has been conducted in determining the in vivo oral bioavailability of encapsulated bioactive compounds. An in vitro simulated gastrointestinal digestion model incorporating gut microbiota and a mucus layer is suggested for future studies.

The viability of complex coacervate encapsulated probiotics during simulated sequential gastrointestinal digestion affected by wall materials and drying methods

The objective of this study was to investigate the impact of protein type (sodium caseinate and pea protein isolate) and protein to sugar beet pectin mixing ratio (5 : 1 and 2 : 1) on complex coacervate formation, as well as the impact of the finishing technology (freeze-drying and spray-drying) for improving the viability of encapsulated Lactobacillus rhamnosus GG (LGG) in complex coacervates during simulated sequential gastrointestinal (GI) digestion. The physicochemical properties of LGG encapsulated microcapsules in liquid and powder form were evaluated. The state diagram and ζ-potential results indicated that pH 3.0 was the optimum pH for coacervate formation in the current systems. Confocal laser scanning microscopy (CLSM), viscoelastic analysis, and Fourier transform infrared spectroscopy (FTIR) confirmed that the gel-like network structure of the complex coacervates was successfully formed between the protein and SBP at pH 3.0 through electrostatic interaction. In terms of physiochemical properties and viability of LGG encapsulated in the microcapsule powder, the drying method played a crucial role on particle size, microstructure and death rate of encapsulated LGG during simulated sequential GI digestion compared to protein type and biopolymer mixing ratio. For example, the microstructure of spray-dried microcapsules exhibited smaller spherical particles with some cavities, whereas the larger particle size of freeze-dried samples showed a porous sponge network structure with larger particle sizes. As a result, spray-dried LGG microcapsules generally had a lower death rate during simulated sequential gastrointestinal digestion compared to their freeze-dried counterparts. Among all samples, spray-dried PPI-SBP microcapsules demonstrated superior performance against cell loss and maintained more than 7.5 log CFU per g viable cells after digestion.

Preparation and Characterization of Microcapsules Containing Antioxidant Fish Protein Hydrolysates: a New Use of Bycatch in Brazil

In this study, we evaluated the effect of complexation and microencapsulation with pea protein on the antioxidant activity of protein hydrolysates from bycatch in Brazil. The zeta potential values of complexes changed from negative to positive with the increase of pea protein as a result of positively charged complexes formation. The increase in the ratio of pea protein/hydrolysates also resulted in increased turbidity in all samples. Particle size measurements indicated that the complexes tended to form larger aggregates (ranged from 61.5 ± 1.7 μm to 183 ± 2.8 μm). The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity of the pea protein/fish protein hydrolysate complexes was higher than that of the protein hydrolysates alone. Moreover, increasing levels of pea protein did not affect the antioxidant activity of fish protein hydrolysates. The complexes of the Paralonchurus brasiliensis were chosen for the microencapsulation process by spray-drying. The results revealed that spray-drying did not have a significant effect (P > 0.05) on the protein hydrolysate antioxidant activity when they were complexed with pea protein. Thus, this work suggests that the complexation with pea protein and subsequent microencapsulation by spray-drying is an efficient way to protect the biological activity of protein hydrolysates obtained from bycatch. This study provides evidence for the potential use of bycatch from shrimp fisheries as functional ingredients or nutraceuticals.

Novel Hydrogel Scaffolds Based on Alginate, Gelatin, 2-Hydroxyethyl Methacrylate, and Hydroxyapatite

Hydrogel scaffolding biomaterials are one of the most attractive polymeric biomaterials for regenerative engineering and can be engineered into tissue mimetic scaffolds to support cell growth due to their similarity to the native extracellular matrix. The novel, versatile hydrogel scaffolds based on alginate, gelatin, 2-hydroxyethyl methacrylate, and inorganic agent hydroxyapatite were prepared by modified cryogelation. The chemical composition, morphology, porosity, mechanical properties, effects on cell viability, in vitro degradation, in vitro and in vivo biocompatibility were tested to correlate the material’s composition with the corresponding properties. Scaffolds showed an interconnected porous microstructure, satisfactory mechanical strength, favorable hydrophilicity, degradation, and suitable in vitro and in vivo biocompatible behavior. Materials showed good biocompatibility with healthy human fibroblast in cell culture, as well as in vivo with zebrafish assay, suggesting newly synthesized hydrogel scaffolds as a potential new generation of hydrogel scaffolding biomaterials with tunable properties for versatile biomedical applications and tissue regeneration.

Enhanced oral absorption and anti-inflammatory activity of ellagic acid via a novel type of case in nanosheets constructed by simple coacervation

As a nature component, ellagic acid (EA) shows a broad array of pharmacological activities but is lost in clinical translation partly due to poor aqueous solubility. In an effort to enhance its oral absorption, novel EA-loaded casein nanosheets (EA@CAS-NSs) was constructed by simple coacervation and investigated for in vitro characterization and in vivo evaluation. The influences of factors including pH, EA concentration, and mass ratio of CAS and EA on properties of EA@CAS-NSs were also studied. The low pH value and high matrix and drug ratio were harmful to small particle size of EA@CAS-NSs. Meanwhile, the low and high concentration of EA went against the 8 h short-term stability of EA@CAS-NSs. Interestingly, EA@CAS-NSs showed a typical disk-like structure with a diameter of 100-400 nm and good long-term storage stability for 24 months. The molecular structure of EA in NSs remained unchanged, but the EA in NSs had lower crystallinity and better thermal stability than in raw state. No chemical interaction occurred between CAS and EA, although the intermolecular distance of them was less than 10 nm. In simulated intestinal fluid, the solubility of EA in NSs was nearly three times that of raw EA, and the dissolution of EA@CAS-NSs was 12 folds of raw EA at 120 min. With oral administration, EA@CAS-NSs demonstrated an improved oral absorption in rats, as evidenced by an AUC_0-24 value 2.34 times higher than raw EA. Also, the EA@CAS-NSs showed a better anti-inflammatory activity than EA. Generally, EA@CAS-NSs could be a potential strategy for the further clinic use of EA.

Preparation and Evaluation of Microcapsules Encapsulating Royal Jelly Sieve Residue: Flavor and Release Profile

This study aimed to improve the flavor of royal jelly residue via microencapsulation technology using Arabic gum and gelatin as wall materials. This microencapsulation technology showed a good encapsulation yield of 85.71 ± 2.84% and encapsulation efficiency of 92.34 ± 3.17%. The intact structures of the microcapsules were observed using optical and scanning electron microscopes. The results of the simulated gastrointestinal digestion proved that the microcapsules were well-tolerated in the gastric environment (a release rate of 32.95 ± 2.34%). Both electronic nose and electronic tongue evaluations showed that microencapsulation improved the sensory index of the royal jelly sieve residue. After microencapsulation, the astringency, bitterness, and irritant odors of the royal jelly residue were reduced. Simultaneously, the release rate in the intestine was 98.77 ± 1.91%, which demonstrated that microencapsulation would not prevent the human body from absorbing the royal jelly. The results from this study are expected to facilitate the development of mild flavor products made from royal jelly.

Effect of sodium chloride on the thermodynamic, rheological, and microstructural properties of field pea protein isolate/chitosan complex coacervates

The effect of increasing sodium chloride concentration (c_NaCl, 0-0.4 M) on the formation and rheological and microstructural properties of field pea protein isolate (FPPI)/chitosan (Ch) complex coacervates was investigated. The maximum turbidity and zeta potential of FPPI/Ch mixtures consistently decreased with the increasing c_NaCl. The tertiary conformation of FPPI was altered to facilitate the aggregation of FPPI/Ch complexes via hydrophobic interactions. Changes in thermodynamic parameters during the titration of FPPI with Ch confirmed the addition of NaCl could cause the inhibition of electrostatic complexation and the induction of non-Coulombic interactions. FPPI/Ch complex coacervates exhibited first enhanced and then weakened viscoelastic properties and an initially tightened and then a loosened microstructure as the c_NaCl increased. In summary, appropriate c_NaCl favors the formation of FPPI/Ch complex coacervates with improved functionalities via the coordination of promoted hydrophobic interactions and inhibited electrostatic attractions, facilitating the application of this protein ingredient in food development.

Microencapsulation of Vanilla Oleoresin (V. planifolia Andrews) by Complex Coacervation and Spray Drying: Physicochemical and Microstructural Characterization

Vanilla is one of the most popular species in the world. Its main compound, vanillin, is responsible for its characteristic aroma and flavor and its antioxidant and biological properties. Vanillin is very unstable in the presence of oxygen, light, and humidity, which complicates its use and preservation. Therefore, to solve this problem, this study aimed to develop vanilla oleoresin microcapsules. Vanilla oleoresin was obtained with supercritical carbon dioxide and microencapsulated by complex coacervation and subsequent spray drying (100 °C/60 °C inlet/outlet temperature). The optimal conditions for the complex coacervation process were 0.34% chitosan, 1.7% gum Arabic, 5.29 pH, and an oleoresin:wall material ratio of 1:2.5. Fourier Transform Infrared Spectroscopy (FT-IR) analysis of the coacervates before and after spray drying revealed the presence of the functional group C=N (associated with carbonyl groups of vanillin and amino groups of chitosan), indicating that microencapsulation by complex coacervation-spray drying was successful. The retention and encapsulation efficiencies were 84.89 ± 1.94% and 69.20 ± 1.79%. The microcapsules obtained from vanilla oleoresin had high vanillin concentration and the presence of other volatile compounds and essential fatty acids. All this improves the aroma and flavor of the product, increasing its consumption and application in various food matrices.

Scaled-up production of gelatin-cellulose nanocrystal bionanocomposite films by continuous casting

In this study, continuous casting is proposed as a suitable approach to scale up the production of gelatin-cellulose nanocrystals (CNCs) bionanocomposites. The processing conditions and bionanocomposite properties were established based on the ζ-potential and gelatin content, and CNCs concentration, respectively. Gelatin film-forming solution at 20 wt% was required for proper continuous casting processing, leading to a productivity of 0.20 m² film/min, which was at least 1000-fold higher than that of the classical bench casting. The gelatin-CNCs bionanocomposites displayed transparency, flexibility, and improved UV-barrier and thermal properties. Adding only 0.5 wt% of CNCs resulted in an increase of 77 % and 48 % in the tensile strength and Young's modulus of gelatin, respectively. Comparison with previous nanocellulose-based nanocomposites pointed out the relatively superior performance of the gelatin-CNCs bionanocomposites obtained by continuous casting for various applications, including flexible food packaging.

Isolation and identification of zinc-chelating peptides from sea cucumber (Stichopus japonicus) protein hydrolysate

BACKGROUND

Zinc is known to play an essential role in the biological activities in the human body. In this study, a zinc-chelating peptide (ZCP) produced by Alcalase-assisted hydrolysis of the body wall of sea cucumber was isolated and identified. The ZCP was purified stepwise by ultrafiltration, anion-exchange chromatography, and gel filtration chromatography, in conjunction with ultraviolet-visual (UV-visual) spectrophotometry, which was used to analyze each purified fraction.

RESULTS

Analysis of the purified ZCP revealed that its zinc-chelating ability was 33.31%. Analysis of isothermal titration calorimetry suggested that the binding of ZCP and zinc (N ≈ 2) was endothermic, with weak binding affinity. Fourier transform infrared spectroscopy spectra (FTIR) indicated that carboxylic and amide groups in ZCP were the primary binding sites of Zn. Sequencing the result by ultra-performance liquid chromatography-quadrupole/time of flight mass spectrometry (UPLC-Q-TOF-MS/MS) showed that a representative ZCP had the sequence WLTPTYPE with a molecular weight of 1005.5 Da.

CONCLUSION

These results provide a promising foundation for the production of zinc supplements from sea-cucumber-derived ZCPs. © 2019 Society of Chemical Industry.

Formation of Nanocomplexes between Carboxymethyl Inulin and Bovine Serum Albumin via pH-Induced Electrostatic Interaction

As a functional polysaccharide, inulin was carboxymethylated and it formed nanocomplexes with bovine serum albumin (BSA). The success of obtaining carboxymethyl inulin (CMI) was confirmed by a combination of Fourier transform Infrared (FT-IR), Raman spectroscopy, gel permeation chromatography (GPC), and titration. The effects of pH and ionic strength on the formation of CMI/BSA nanocomplexes were investigated. Our results showed that the formation of complex coacervate (pHφ1) and dissolution of CMI/BSA insoluble complexes (pHφ2) appeared in pH near 4.85 and 2.00 respectively. FT-IR and Raman data confirmed the existence of electrostatic interaction and hydrogen bonding between CMI and BSA. The isothermal titration calorimetry (ITC) results suggested that the process of complex formation was spontaneous and exothermic. The complexation was dominated by enthalpy changes (∆Η < 0, ∆S < 0) at pH 4.00, while it was contributed by enthalpic and entropic changes (∆Η < 0, ∆S > 0) at pH 2.60. Irregularly shaped insoluble complexes and globular soluble nanocomplexes (about 150 nm) were observed in CMI/BSA complexes at pH 4.00 and 2.60 while using optical microscopy and atomic force microscopy, respectively. The sodium chloride suppression effect on CMI/BSA complexes was confirmed by the decrease of incipient pH for soluble complex formation (or pHc) and pHφ1 under different sodium chloride concentrations. This research presents a new functional system with the potential for delivering bioactive food ingredients.

Development of alginate hydrogel/gum Arabic/gelatin based composite capsules and their application as oral delivery carriers for antioxidant

We have designed microcapsules-immobilized composite capsules and evaluated the oral delivery efficacy. The composite capsules were developed by encapsulating Perinereis aibuhitensis extract (PaE), a model substance possessing antioxidant activity, loaded gum Arabic/gelatin microcapsules in calcium alginate (CA) hydrogel (PaE:CA/GA/GE-CCs). In vitro antioxidant assay showed the obtained composite capsules were able to protect PaE from gastric acid, since O₂^- scavenging rate of encapsulated PaE was about 1.8 folds as that of free PaE after 5 h incubation in simulated gastrointestinal fluid. Moreover, in vivo study showed that after the treatment of oral administration for 30 days, the mice of PaE:CA/GA/GE-CCs group suffered significantly lower oxidative stress level than those of other groups, illustrated as higher SOD and catalase activity, as well as lower malondialdehyde content in liver cells. The results demonstrated the composite capsules could concentrate PaE in small intestine, and enhance the absorption efficiency and in vivo efficacy.