Formulation and stabilization of high internal phase emulsions: Stabilization by cellulose nanocrystals and gelatinized soluble starch

Sustained-release mechanism of β-Cyclodextrin/cationic cellulose-stabilized Pickering emulsions loaded with citrus essential oil

Citrus oil (CO) is a commonly used natural flavor with high volatility, which is not conducive to sustained release under food environmental stress. This study constructed novel β-cyclodextrin/cationic cellulose nanocrystal (β-CD/C-CNC) complexes via noncovalent interaction, which were used to stabilize CO-loaded Pickering emulsions (PEβ-CD/C-CNC). The C-CNC greatly improved the physical stability, droplet dispersion and viscoelasticity of PEβ-CD/C-CNC by forming a tight network structure, as verified by rheological behavior. Moreover, C-CNC improved the wettability of β-CD/C-CNC complexes and enhanced the interaction between adjacent β-CD/C-CNC complexes. C-CNC also contributed to the interfacial viscoelasticity, hydrated mass, and layer thickness via the interfacial dilational modulus and QCM-D. β-CD/C-CNC complexes adsorbed on the oil-water interface gave rise to a dense filling layer as a physical barrier, enhancing the sustained-release performance of PEβ-CD/C-CNC by limiting diffusion of citrus essential oil into the headspace. This study provides new technical approaches for aroma retention in the food industry.

Characterization of Alginate-Crystalline Nanocellulose Composite Hydrogel as Polyphenol Encapsulation Agent

Alginate hydrogel is broadly known for its potential as an encapsulation agent due to its compatibility and versatility. Despite its predominance, alginate hydrogel naturally has macropores and a less rigid structure, which leads to syneresis and uncontrolled diffusion of bioactive compounds from the gel network. Combining alginate with other biopolymers has been considered to improve its properties as an encapsulation agent. This research aimed to evaluate the effect of Crystalline Nanocellulose (CNC) to the physical properties and the diffusion of gallic acid (GA), as a water-soluble polyphenol model, through the alginate-CNC composite hydrogels performed as an encapsulation agent. The hydrogel mixtures were made from 1:0, 1:1, 2:0, 2:1, 2:2, and 2:3 solid-basis ratio of sodium alginate:crystalline nanocellulose and evaluated for syneresis, gel strength and stiffness, rehydration properties and gel porosity. Alginate-CNC and GA interaction was observed through zeta-potential analysis and Fourier Transform Infrared (FTIR) spectroscopy. Results showed that composite hydrogel with the highest proportion of CNC increased the gel rehydration capacity (87.33 %), gel strength and stiffness as well as reduced the gel syneresis (14.72 %) and dried gel porosity (0.62). GA pre-loaded gel with 2:2 and 2:3 S-C ratios reduced the diffusion of gallic acid by 92.07-92.27 %. FTIR showed hydrogen bonding between GA and the alginate-CNC hydrogel. Alginate-CNC hydrogel had a fibrous and compact structure as shown in the cryo-SEM and confocal microscope images.

Enhancing cellulose-stabilized multiphase/Pickering emulsions systems: A molecular dynamics perspective

Cellulose stabilized multiphase systems (CSMS) have garnered significant attention due to their ultra-stabilization mechanism and vast potential across different fields. CSMS have found valuable applications in scientific disciplines, including Food Science, Pharmaceutical Science, Material Science, and related fields, owing to their beneficial attributes such as sustainability, safety, renewability, and non-toxicity. Furthermore, MPS exhibit novel characteristics that enable multiple mechanisms to produce HIPEs, aerogels, and oleogels revealing undiscovered information. Therefore, to explore the undiscovered phenomena of MPS, molecular level insights using advanced simulation/computational approaches are essential. The molecular dynamics simulation (MDS), play a valuable role in analyzing the interactions of ternary interphase. The MDS have successfully quantified the interactions of MPS by generating, visualizing, and analyzing trajectories. Through MDS, researchers have explored CSMS at the molecular level and advanced their applications in 3D printing, packaging, preparation, drug delivery, encapsulation, biosensors, electronic devices, biomaterials, and energy conservation. This review highlights the remarkable advancements in CSMS over the past five years, along with contributions of MDS in evaluating the relationships that dictate the functionality and properties of CSMS. By integrating experimental and computational methods, we underscore the potential to innovate and optimize these multiphase systems for groundbreaking applications.

Encapsulation, characterization and in vitro releasing of xylanase and glucose oxidase (GOD) into cellulose nanocrystals stabilized three-layer microcapsules

The xylanase and glucose oxidase (GOD) are easily inactivated, restricting their applicaiton in food and agriculture fields. In this work, xylanase and glucose oxidase (GOD) were encapsulated into cellulose nanocrystals (CNC) stabilized three-layer microcapsules via ionic gelation technique to improve their bioavailability and targeted delivery. Encapsulation efficiency (EE), physicochemical properties, and in vitro releasing of xylanase and GOD encapsulated in microcapsules were investigated. EE of xylanase and GOD reached the highest values (73.34 % and 67.16 %, respectively) at an enzyme concentration of 35 mg/mL. In vitro experiments revealed that cumulative release of both enzymes encapsulated in microcapsules was greater than that of controls in simulated gastric tract (SGT) and simulated intestinal tract (SIT). The release of xylanase increased from 41.62 % (gastric tract) to 77.13 % (intestine tract), and release of GOD increased from 42.63 % to 72.11 %, respectively. Novel hydrogel carriers as enzymes encapsulation system could effectively improve the survival rate of enzymes in harsh environments and could be widely employed in food, feed and other industries.

Physicochemical and antimicrobial properties of soy protein isolate films incorporating high internal phase emulsion loaded with thymol

Oil-in-water (O/W) high internal phase (HIP) emulsion was prepared to investigate its effects on the physicochemical properties and antimicrobial properties of soy protein isolate (SPI)-based films. The particle size and migration degree of oil droplets in the SPI film-forming solution with HIP emulsion and the films were lower than those with conventional O/W emulsion or oil. The SPI-based emulsion films with HIP emulsion containing 30 % oil had the lowest water vapor permeability (1.15 × 10-10 g·m-1·s-1·Pa-1), glass transition temperature (40.93 °C) and tensile strength (4.47 MPa), and the highest transparency value (12.87) and elongation at break (160.83 %). The antimicrobial test of the SPI-based emulsion films loaded with thymol showed that the thymol encapsulation efficiency, sustained release effect, and growth inhibition effect on microbes were higher for the films with HIP emulsion than those for the films with O/W emulsion or oil.

Pea protein/carboxymethyl cellulose complexes prepared using a pH cycle strategy as stabilizers of high internal phase emulsions for 3D printing

The development of food-grade high internal phase emulsions (HIPEs) for 3D printing and the replacement of animal fats have attracted considerable attention. In this study, in order to improve the rheological properties and stability of pea protein to prepare HIPE, pea protein/carboxymethyl cellulose (pH-PP/CMC) was prepared and subjected to pH cycle treatment to produce HIPEs. The results showed that pH cycle treatment and CMC significantly reduced the droplet size of HIPEs (from 143.33 to 12.10 μm). At higher CMC concentrations, the interfacial tension of the PP solution decreased from 12.84 to 11.71 mN/m without pH cycle treatment and to 10.79 mN/m with pH cycle treatment. The HIPEs with higher CMC concentrations subjected to pH cycle treatment showed shear thinning behavior and higher viscoelasticity and recovered their solid-like properties after being subjected to 50 % strain, indicating that they could be used for 3D printing. The 3D printing results showed that the pH-PP/CMC HIPE with 0.3 % CMC had the finest structure. Our work provides new insights into developing food-grade HIPEs and facilitating their use in 3D printing inks as nutrient delivery systems and animal fat substitutes.

Application of carboxymethylcellulose in combination with essential oils nano-emulsions edible coating for the preservation of kiwifruit

The present research investigates the effectiveness of nano-emulsified coatings (C-1, C-2, and C-3) in preserving the kiwifruit at a temperature of 10 ± 2 °C with 90-95 % relative humidity (RH) for 30 days. The nano-emulsions were prepared from varied carboxymethyl cellulose (CMC) concentrations with different combinations of essential oils such as thyme, clove, and cardamom. Dynamic light scattering investigation with Zeta Sizer revealed that C-1, C-2, and C-3 nano-emulsions have nano sizes of 81.3 ± 2.3, 115.3 ± 4.2, and 63.2 ± 3.2 nm, respectively. The scanning electron microscopy images showed that the nanoemulsion of C-1 had homogenous spherical globules, C-2 had voids, and C-3 showed a non-porous structure with uniform dispersion. The X-ray diffraction analysis indicated that C-1, C-2, and C-3 nano-emulsion exhibited distinct crystallinity and peaks. The nano-emulsion C-1 had reduced crystallinity, while C-2 had lower intensity peaks, and C-3 had increased crystallinity. The results documented that compared to control kiwifruit samples, the samples coated with C-3 nano-emulsion have decreased weight loss, decay incidence, soluble solids, maturity index activity, ethylene production, total bacterial count, and increased titratable acid, and firmness attributes. The results of current research are promising and would be applicable in utilization in industrial applications.

Analysis of instability of starch-based Pickering emulsion under acidic condition of pH < 4 and improvement of emulsion stability

Starch-based Pickering emulsions exhibit high interfacial stability in a certain range of mild pH environments. On the contrary, many studies have reported that when the pH value is <4, it often leads to different degrees of emulsion instability. In this paper, the microscopic state of starch granules in the emulsion and its effect on the stability of the emulsion were observed and analyzed by atomic force microscope (AFM) in tapping mode. At the same time, Pickering emulsions in acidic environment were prepared by using the gel properties of methyl cellulose (MC) in synergy with esterified high amylose maize starch (M-HAMS) granules. The results show that in the emulsion with pH 3, the excessive H + ion inhibits the swelling of M-HAMS granules and prevents it from forming a stable gel structure, which is the main cause of emulsion instability. The polarity of MC with water contact angle (WCA) of 81.8° is similar to that of M-HAMS granules with WCA of 80.1°, and a uniform and ordered micro-nanostructure is formed in the aqueous phase. The prepared acidic (pH 3-4) emulsion has good stability during the observation period of 30 days.

Fabrication of jamun seed starch/tamarind kernel xyloglucan bio-nanocomposite films incorporated with chitosan nanoparticles and their application on sapota (Manilkara zapota) fruits

The present work develops bio-nanocomposite packaging films by valorizing agricultural byproducts jamun seed starch (JaSS) and tamarind kernel xyloglucan (XG), and adding varying concentrations of chitosan nanoparticles (ChNPs). The blending of JaSS and XG promotes a dense polymer network in the composite films with enhanced packaging attributes. However, ChNPs incorporation significantly reduced the viscosity and dynamic moduli of the JaSS/XG film-forming solutions. The FTIR and XRD results reveal improved intermolecular interactions and crystallinity. The DSC and TGA thermograms showed improved thermal stability in the ChNP-loaded JaSS/XG films. The addition of 3 % w/w ChNPs significantly enhanced the tensile strength (20.42 MPa), elastic modulus (0.8 GPa), and contact angle (89°), along with reduced water vapor transmission rate (13.26 g/h.m2) of the JaSS/XG films. The films exhibited strong antimicrobial activity against Bacillus cereus and Escherichia coli. More interestingly, the JaSS/XG/ChNPs coating on the sapota fruits retarded the weight loss and color change up to 12 days of storage. Overall, the JaSS/XG/ChNP bio-nanocomposites are promising packaging materials.

Protein-stabilized Pickering emulsion interacting with inulin, xanthan gum and chitosan: Rheological behavior and 3D printing

Physical stability and lipid digestion of protein-stabilized Pickering emulsions interacting with polysaccharides have been emphasized in our previous investigation. However, the polysaccharide coating and micelle protection of protein-based stable Pickering emulsion and its three-dimensional (3D) printing properties have not been thoroughly studied. The rheological properties and 3D printing properties of gelatin-catechin nanoparticles (GCNPs) stabilized Pickering emulsion were studied by using different charged polysaccharides, such as inulin (neutral), Xanthan gum (XG, anion), and chitosan (cation) as stable materials. The microstructure analysis of polysaccharide-stabilized Pickering emulsion (PSPE) showed that the order of pore wall thickness was GC-Chitosan > GC-XG > GC-Inulin. The network structure of GC-Chitosan was thickened, allowing the 3D printed product to have a good surface texture and adequate support. Rheological analysis showed that PSPEs in extrusion (shear thinning), self-support (rigid structure), and recovery (the outstanding thixotropy) of the three stages exhibited good potential of 3D printing. 3D printing results also showed that GC-Chitosan had the best printing performance. Therefore, polysaccharide-stabilized Pickering emulsions can provide a basis for the development of 3D printed food products.

Extraction of cellulose nanocrystalline from Camellia oleifera Abel waste shell: Study of critical processes, properties and enhanced emulsion performance

Cellulose nanocrystals (CNCs) extracted from the waste shell of Camellia oleifera Abel (C. oleifera) are gaining attention as valuable materials. In this study, CNCs were extracted from the agricultural waste shell of C. oleifera through phosphoric acid and sulfuric acid hydrolysis, respectively. Firstly, we optimized the alkaline treatment process for cellulose isolation by using response surface methodology. Furthermore, the properties of CNCs were investigated by neutralizing them with NaOH and NH3·H2O, and by dialysis in water. In addition, the characterization methods including FT-IR, TGA, AFM and TEM were used to analysis the properties of the synthesized CNCs. Finally, CNCs were studied for their application in essential oil-based Pickering emulsions. CNCs obtained from sulfuric acid showed the smallest particle size and good dispersibility. Moreover, the release profiles of essential oils in the emulsions were followed by Peppa's kinetic release model. The antibacterial activity of the emulsions against E. coli and S. aureus showed that CNCs-stabilized emulsions enhanced the antibacterial activity of essential oils. Therefore, neutralization treatments may enhance the properties of CNCs, and CNCs stabilized Pickering emulsions can enhance antibacterial activity of essential oil. This study provides insight into the potential application of CNCs derived from C. oleifera waste shells.

Stabilization of oil-in-water high internal phase emulsions with octenyl succinic acid starch and beeswax oleogel

High internal phase emulsions (HIPEs) based on beeswax (BW) oleogels and octenyl succinic acid starch (OSA starch) were prepared by a facile one-step method. Effects of the oleogelation of internal phase on the formation, stability and functionality of the HIPEs were investigated. OSA starch absorbed at the interface allowed high surface charge (|ζ| > 25 mV) of the droplets, and small droplet size (d ≈ 5 m). Microstructural observation suggested that the HIPEs were of O/W type with droplets packed tightly. With the increase in BW content (0-4 %), the particle size (4-7 μm) and ζ-potential (-25 ~ -30 mV) of the HIPEs were first decreased and then increased. Stability analysis revealed that the addition of BW effectively improved emulsion stability against centrifugation, freeze-thawing, changes in pH and ionic strength, and the HIPE with 2 % BW presented the best stability. Rheological tests indicated that the HIPEs with higher content of BW exhibited higher storage modulus, solid-like properties, and shear thinning behaviors. Creep-recovery results implied that the oleogelation enhanced the structure of HIPEs and improved the deformation resistance of the systems. When subjected to light and heat, oleogel-in-water HIPEs showed advantages in protecting β-carotene from degradation, and β-carotene in the HIPEs with 2 % BW had the lowest degradation rate. These findings suggested that gelation of oil phase could improve the stability of HIPEs and the encapsulation capability, which would be meaningful for the development of novel healthy food.