Advanced methods to mechanically isolate stromal vascular fraction: A concise review

Adipose tissue is a highly attractive reservoir of stem cells due to its accessibility and abundance, and the SVF within it holds great promise for stem cell-based therapies. The use of mechanical methods for SVF isolation from adipose tissue is preferred over enzymatic methods, as it can be readily applied in clinical settings without additional processing steps. However, there is a lack of consensus on the optimal approach for mechanically isolating SVF. This comprehensive review aims to present and compare the latest mechanical isolation methods for SVF from adipose tissue, including centrifugation, filtration/washing, emulsification, vibration, and mincing/adiponizing. Each of these methods possesses unique advantages and limitations, and yet, no conclusive evidence has emerged demonstrating the superiority of one approach over the others, primarily due to the dearth of well-controlled prospective studies in this field.

Insight into the mechanisms of combining direct current magnetic field with phosphate in promoting emulsifying properties of myofibrillar protein

This study investigated the combined effects of direct-current magnetic field (DC-MF, 9.5 mT) and tetrasodium-pyrophosphate (TSPP, 1-5 g/L) on emulsified gel properties of porcine myofibrillar protein (MP). Results showed that MP at DC-MF and 3 g/L TSPP had decreased spectrum intensity of UV and fluorescence compared to that without DC-MF, owing to the changes of MP tertiary structure caused by DC-MF, especially tryptophan and tyrosine. The emulsion treated with DC-MF behaved better emulsifying activity and stability than that without DC-MF under such condition. And emulsion had lower creaming index and better storage stability. Gels prepared by this MP emulsion had low porosity and stable structure, accompanying with smaller size and more uniform distribution of oil droplets. Microstructure images showed that gels were covered with microporous structure, which was conducive to the good WHC of the emulsified gels (97.12%). These results showed the feasibility of DC-MF and TSPP in improving MP emulsion/emulsified gel.

Effect of vegetable oils on the thermal gel properties of PSE-like chicken breast meat protein isolate-based emulsion gels

To enhance the gel properties of PSE (pale, soft, and exudative)-like chicken meat protein isolate (PPI), the effect of peanut, corn, soybean, and sunflower oils on the gel properties of PPI emulsion gels was investigated. Vegetable oils improved emulsion stability and gel strength and enhanced viscosity and elasticity. The gel strength of the PPI-sunflower oil emulsion gel increased by 163.30 %. The thermal denaturation temperature and enthalpy values were increased. They decreased the particle size of PPI emulsion (P < 0.05) and changed the three-dimensional network structure of PPI emulsion gels from reticular to sheet with a smooth surface and pore-reduced lamellar. They elevated the content of immobile water PPI emulsion gels, decreased the α-helix and β-turn, and increased the β-sheet and random coil. Vegetable oil improved the gel properties of PPI in the following order: sunflower oil > soybean oil > corn oil ≈ peanut oil > control group.

Degradation and enhanced oil recovery potential of Alcanivorax borkumensis through production of bio-enzyme and bio-surfactant

Microbial enhanced oil recovery (EOR) has become the focus of oilfield research due to its low cost, environmental friendliness and sustainability. The degradation and EOR capacity of A. borkumensis through the production of bio-enzyme and bio-surfactant were first investigated in this study. The total protein concentration, acetylcholinesterase, esterase, lipase, alkane hydroxylase activity, surface tension, and emulsification index (EI) were determined at different culture times. The bio-surfactant was identified as glycolipid compound, and the yield was 2.6 ± 0.2 g/L. The nC12 and nC13 of crude oil were completely degraded, and more than 40.0 % of nC14-nC24 was degraded by by A. borkumensis. The results of the microscopic etching model displacement and core flooding experiments showed that emulsification was the main mechanism of EOR. A. borkumensis enhanced the recovery rate by 20.2 %. This study offers novel insights for the development of environmentally friendly and efficient oil fields.

General approaches to biopolymer-based Pickering emulsions

Pickering emulsion is a type of emulsion that uses solid particles or colloidal particles as emulsifiers rather than surfactants to adhere at oil-water interface. Pickering emulsions have gathered significant research attention recently due to their excellent stability and wide range of potential uses compared to traditional emulsions. Major advancements have been made in development of innovative Pickering emulsions using different colloidal particles by various techniques including homogenization, emulsification and ultrasonication. Use of biopolymer particles gives Pickering emulsions a more escalating possibilities. In this review paper, we seek to present a critical overview of development in food-grade particles that have been utilized to create Pickering emulsions with a focus on techniques and application of Pickering emulsions. Particularly, we have evaluated protein, lipid, polysaccharide-based particles and microalgal proteins that have emerged in recent years with respect to their potential to stabilize and add novel functionalities to Pickering emulsions. Some preparation methods of Pickering emulsions in brief, applications of Pickering emulsions are also highlighted. Encapsulation and delivery of bioactive compounds, fat substitutes, film formation and catalysis are potential applications of Pickering emulsions. Pickering double emulsions, nutraceutical and bioactive co-delivery, and preparation of porous materials are among research trends of food-grade Pickering emulsions.

Exploring the emulsification potential of chitosan modified with phenolic acids: Emulsifying properties, functional activities, and application in curcumin encapsulation

This study successfully grafted caffeic acid and 3,4-dihydroxybenzoic acid into chitosan through a coupling reaction, yielding grafting ratio of 8.93 % for caffeic acid grafted chitosan (CA-GC) and 9.15 % for 3,4-dihydroxybenzoic acid grafted chitosan (DHB-GC) at an optimal concentration of 4 mmol phenolic acids. The characterization of modified chitosans through ultraviolet visible spectrometer (UV-vis), Fourier transform infrared spectrometer (FTIR), proton nuclear magnetic resonance (1H NMR), and x-ray photoelectron spectrometer (XPS) confirmed the successful grafting of phenolic acids. In the subsequent step of emulsion preparation, confocal laser scanning microscope images confirmed the formation of O/W (oil-in-water) emulsions. The phenolic acid-grafted chitosans exhibited better emulsification properties compared to native chitosan, such as reduced droplet size, more uniform emulsion droplet distribution, increased ζ-potential, and enhanced emulsifying activity and stability. Moreover, the modified chitosans demonstrated increased antioxidant activities (evidenced by DPPH and β-carotene assays) and displayed greater antimicrobial effects against E. coli and S. aureus. Its efficacy in curcumin encapsulation was also notable, with improved encapsulation efficiency, sustained release rates, and enhanced storage and photostability. These findings hint at the potential of modified chitosans as an effective emulsifier.

Fabrication and characterization of dual-functional porous starch with both emulsification and antioxidant properties

Starchy materials with good antioxidant, emulsification and adsorption properties have potential applications in industry. To improve these properties, a Dual-functional porous starch was prepared through one-pot synthesis. In this case, octenyl succinic anhydride (OSA) and syringic acid (SA) were selected to modify the porous starch (PS) by esterification, with subsequent signals recorded by 1H NMR at 1.2 ppm and FT-IR at 1743 cm-1, indicating the formation of Dual-functional porous starch grafted by OSA and SA. N2 adsorption analysis further proved that the porous structure (2.9 m2g-1) was still maintained after modification. This was followed by measurements of droplet size distribution (34.18 ± 3.80 μm), zeta potential (-39.62 ± 1.89 mV) and emulsion index (85.10 ± 1.76 %), all of which indicated good emulsifying capacity. Meanwhile, results of radical scavenging assay proved that the Dual-functional porous starch had considerable antioxidant properties due to the introduction of SA groups. Besides, the Dual-functional porous starch also showed good resistance to digestion. These findings not only provide a novel strategy for constructing multi-functionalized starchy materials, but also open up potential applications of starch in the food and pharmaceutical industries.

Investigating the effect of catechin on the emulsification and oxidation stability of myofibrillar protein-diacylglycerol emulsions

The effects of catechin on the emulsification and oxidation stability of myofibrillar protein-diacylglycerol (MP-DAG) emulsions were investigated. Lard samples, namely, lard, unpurified glycerolytic lard (UGL), and purified glycerolytic lard (PGL), were used as oil phases. The emulsifying effects of UGL- and PGL-based emulsions were superior to those of lard-based emulsions (P < 0.05). The emulsifying properties of MP-DAG emulsions increased initially and then decreased with a rise in the catechin concentration, with 20-μmol/g catechin exhibiting optimal emulsification activity and stability (P < 0.05). The droplets were tinier and evenly distributed, and the absolute ξ-potential values and rheological characteristics reached their maximum at a catechin concentration of 20 μmol/g. The formation of thiobarbituric acid-reactive substances and carbonyls declined significantly with the growth of catechin levels (P < 0.05), which confirmed that the oxidation of MPs and lipids was reduced efficiently by catechin. This study provides an idea for improving the emulsification and oxidation stability of MP-DAG emulsions, which offers a theoretical basis for the application of MP-DAG emulsions in meat products.

Performance evaluation of rhamnolipid biosurfactant produced by Pseudomonas aeruginosa and its effect on marine oil-spill remediation

This study aimed to reveal that the effect of biosurfactant on the dispersion and degradation of crude oil. Whole genome analysis showed that Pseudomonas aeruginosa GB-3 contained abundant genes involved in biosurfactant synthesis and metabolic processes and had the potential to degrade oil. The biosurfactant produced by strain GB-3 was screened by various methods. The results showed that the surface tension reduction activity was 28.6 mN·m-1 and emulsification stability was exhibited at different pH, salinity and temperature. The biosurfactant was identified as rhamnolipid by LC-MS and FTIR. The fermentation conditions of strain GB-3 were optimized by response surface methodology, finally the optimal system (carbon source: glucose, nitrogen source: ammonium sulfate, C/N ratio:16:1, pH: 7, temperature: 30-35 °C) was determined. Compared with the initial fermentation, the yield of biosurfactant increased by 4.4 times after optimization. In addition, rhamnolipid biosurfactant as a dispersant could make the dispersion of crude oil reach 38% within seven days, which enhanced the bioavailability of crude oil. As a biostimulant, it could also improve the activity of indigenous microorganism and increase the degradation rate of crude oil by 10-15%. This study suggested that rhamnolipid biosurfactant had application prospect in bioremediation of marine oil-spill.

Diversity and enzymatic, biosurfactant and phytotoxic activities of culturable Ascomycota fungi present in marine sediments obtained near the South Shetland Islands, maritime Antarctica

We studied the culturable fungal community recovered from deep marine sediments in the maritime Antarctic, and assessed their capabilities to produce exoenzymes, emulsifiers and metabolites with phytotoxic activity. Sixty-eight Ascomycota fungal isolates were recovered and identified. The most abundant taxon recovered was the yeast Meyerozyma guilliermondii, followed by the filamentous fungi Penicillium chrysogenum, P. cf. palitans, Pseudeurotium cf. bakeri, Thelebolus balaustiformis, Antarctomyces psychrotrophicus and Cladosporium sp. Diversity indices displayed low values overall, with the highest values obtained at shallow depth, decreasing to the deepest location sampled. Only M. guilliermondii and P. cf. palitans were detected in the sediments at all depths sampled, and were the most abundant taxa at all sample sites. The most abundant enzymes detected were proteases, followed by invertases, cellulases, lipases, carrageenases, agarases, pectinases and esterases. Four isolates showed good biosurfactant activity, particularly the endemic species A. psychrotrophicus. Twenty-four isolates of P. cf. palitans displayed strong phytotoxic activities against the models Lactuca sativa and Allium schoenoprasum. The cultivable fungi recovered demonstrated good biosynthetic activity in the production of hydrolytic exoenzymes, biosurfactant molecules and metabolites with phytotoxic activity, reinforcing the importance of documenting the taxonomic, ecological and biotechnological properties of fungi present in deep oceanic sediments of the Southern Ocean.

Beef protein ingredients from fat rendering process are promising functional ingredients

The valorization of co-products may be a promising way to meet the dual challenge of increasing global food resources and sustainability of food systems. In particular, meat co-products may be nutritionally interesting protein resources, if they offer functional properties in accordance with food applications. In that aim, two bovine co-products, resulting from the fat rendering process, have been characterized, regarding the protein solubility, gelling, and emulsifying properties. The effect of protein concentration, pH variation and NaCl addition on these properties was tested. Despite an effect of the ionic strength on the protein solubility of the two ingredients, a little or no significant impact was observed on the functionalities. Similarly, the functional properties were scarcely affected by pH. In the end, the protein concentration has proven to be the only important parameter, which points to an easy utilization of these ingredients in many food conditions.

Enhance the resistance of probiotics by microencapsulation and biofilm construction based on rhamnogalacturonan I rich pectin

Microcapsules were always used as functional material carriers for targeted delivery and meanwhile offering protection. However, microcapsule wall materials with specific properties were required, which makes the choice of wall material a key factor. In our previous study, a highly branched rhamnogalacturonan I rich (RG-I-rich) pectin was extracted from citrus canning processing water, which showed good gelling properties and binding ability, indicating it could be a potential microcapsule wall material. In the present study, Lactiplantibacillus plantarum GDMCC 1.140 and Lactobacillus rhamnosus were encapsulated by RG-I-rich pectin with embedding efficiencies of about 65 %. The environmental tolerance effect was evaluated under four different environmental stresses. Positive protection results were obtained under all four conditions, especially under H2O2 stress, the survival rate of probiotics embedded in microcapsules was about double that of free probiotics. The storage test showed that the total plate count of L. rhamnosus encapsulated in RG-I-rich pectin microcapsules could still reach 6.38 Log (CFU/mL) at 25 °C for 45 days. Moreover, probiotics embedded in microcapsules with additional incubation to form a biofilm layer inside could further improve the probiotics' activities significantly in the above experiments. In conclusion, RG-I-rich pectin may be a good microcapsule wall material for probiotics protection.

Tunability of Pickering particle features of whey protein isolate via remodeling partial unfolding during ultrasonication-assisted complexation with chitosan/chitooligosaccharide

The potential of ultrasonication-driven molecular self-assembly of whey protein isolate (WPI) with chitosan (CS)/chitooligosaccharide (COS) to stabilize Pickering emulsions was examined, based on CS/COS ligands-induced partial unfolding in remodeling the Pickering particles features. Multi-spectral analysis suggested obvious changes in conformational structures of WPI due to interaction with CS/COS, with significantly higher unfolding degrees of WPI induced by COS. Non-covalent interactions were identified as the major forces for WPI-CS/COS conjugates. Ultrasonication enhanced electrostatic interaction between CS's -NH3 groups and WPI's -COO- groups which improved emulsification activity and storability of WPI-COS stabilized Pickering emulsion. This was attributed to increased surface hydrophobicity and decreased particle size compared to WPI-CS associated with differential unfolding degrees induced by different saccharide ligands. CLSM and SEM consistently observed smaller emulsion droplets in WPI-COS complexes than WPI-CS/COS particles tightly adsorbed at the oil-water interface. The electrostatic self-assembly of WPI with CS/COS greatly enhanced the encapsulation efficiency of quercetin than those stabilized by WPI alone and ultrasound further improved encapsulation efficiency. This corresponded well with the quantitative affinity parameters between quercetin and WPI-CS/COS complexes. This investigation revealed the great potential of glycan ligands-induced conformational transitions of extrinsic physical disruption in tuning Pickering particle features.

Emulsification and encapsulation properties of conjugates formed between whey protein isolate and carboxymethyl cellulose under acidic conditions

In this study, carboxymethyl cellulose (CMC) was used to interact with whey protein isolate (WPI) to prepare conjugates as emulsifiers and embedding agents, which can be used under acidic conditions. Firstly, the effects of ratios and pH values on the formation of WPI-CMC conjugates were investigated. The turbidity and particle size of WPI were reduced in the presence of CMC at pH 4.6 (near the isoelectric point). Then the characterization of physicochemical properties indicated that electrostatic interactions played a major role in the formation of WPI-CMC conjugates, thereby changing the structure and function of conjugates. CMC and WPI reached the optimal aggregation state at pH 4.6 and a ratio of 4:1. The conjugates exhibited excellent emulsifying activity and stability for the oil-in-water emulsions. WPI-CMC conjugates also could provide protection to allicin by preventing degradation under environmental stresses, while maintaining its antioxidant activity.

Emulsion template fabricated gelatin-based scaffold functionalized by dialdehyde starch complex with antibacterial antioxidant properties for accelerated wound healing

Gelatin and starch are considered as promising sustainable materials for their abundant production and good biodegradability. Efforts have been made to explore their medical application. Herein, scaffolds based on gelatin and starch with a preferred microstructure and antibacterial antioxidant property were fabricated by the emulsion template method. The dialdehyde starch was firstly combined with silver nanoparticles and curcumin to carry out the efficient hybrid antibacterial agent. Then, the gelatin microsphere of appropriate size was prepared by emulsification and gathered by the above agent to obtain gelatin-based scaffolds. The prepared scaffolds showed porous microstructures with high porosity of over 74 % and the preferred pore sizes of ∼65 μm, which is conducive to skin regeneration. Moreover, the scaffolds possessed a good swelling ability of over 640 %, good degradability of over 18 days, excellent blood compatibility, and cell compatibility. The promising antibacterial and antioxidant properties came from the hybrid antibacterial agent were affirmed. As expected, the gelatin-based scaffolds fabricated by the emulsion template method with a preferred microstructure can facilitate more adhered fibroblasts. In summary, gelatin-based scaffolds functionalized by starch-based complex expanded the application of abundant sustainable materials in the biomedical field, especially as antibacterial antioxidant wound dressings.

Visualization and Identification of Silicone Oil Emulsification Using Dynamic Infrared Confocal Scanning Laser Ophthalmoscopy

Introduction

Silicone oil (SO) is a crucial agent used as an intraocular tamponade in the treatment of complex vitreoretinal diseases. Despite its effectiveness, SO is prone to emulsification, which can lead to significant and sometimes irreversible complications in both the anterior and posterior segments of the eye. The detection and monitoring of SO emulsification are therefore of paramount importance. Traditional imaging modalities have limitations in visualizing SO, leading to the exploration of more advanced imaging techniques. This study introduces the application of dynamic infrared confocal scanning laser ophthalmoscopy (IRcSLO) for this purpose and evaluates its effectiveness.

Case Presentation

We report on 2 patients who underwent pars plana vitrectomy with subsequent SO injection for the management of retinal detachment. Postsurgery, both patients were imaged using the Heidelberg Retina Tomography Spectralis IRcSLO. The focus was on the visualization of the SO status, including the presence and distribution of emulsified SO droplets. The IRcSLO imaging technique demonstrated its capability to effectively visualize emulsified SO droplets. Interestingly, this was also true for cases where the SO had been removed. The emulsified droplets were observed as micron-sized, spherical entities with a nonuniform distribution throughout the vitreous cavity.

Conclusion

Dynamic IRcSLO has proven to be an effective imaging modality for visualizing the emulsification of SO, offering a novel perspective into the characterization of SO droplets. It facilitates the analysis of droplet count, motility, and precise localization within the vitreous cavity. The findings from the case presentations underscore the variability of SO emulsification patterns and the sensitivity of IRcSLO in detecting even minuscule emulsified droplets. This imaging technique has significant potential for future research, particularly in understanding the timing of emulsification, the factors contributing to it, and the development of possible preventive strategies. Additionally, it allows for a more in-depth analysis of the behavior of emulsified SO droplets across different SO viscosities, which could be instrumental in optimizing patient outcomes.

Experimental investigation on the performance characteristics and emissions of a CI engine fueled with enhanced microwave-assisted Karanja seed bio-oil

The main objective of the present research work is to utilise the produced bio-oil from microwave pyrolysis of Karanja, a non-edible seed, as fuel for diesel engines by increasing some up-gradation in the quality of the fuel. The emulsification process is carried out to improve the stability of the diesel-bio-oil blend using SPAN 80 and TWEEN 80, which lasted for 28 days without any layer separation termed as EKB20. The addition of 5% DEE and 10% DEE into EKB20 is done to enhance the combustion characteristics of the diesel engine. The produced bio-oil fuels were tested in a Kirloskar make, four-stroke, single-cylinder, direct injection diesel engine of 5.2 kW rated power output. The addition of DEE reduces the peak pressure by 4 bar and increases the heat release rate due to the higher volatility of DEE. At full load conditions, the thermal brake efficiency improved by 9.31% and 14.11%, respectively, compared to EKB20. Adding 5% DEE and 10% DEE at the rated power output reduced the smoke density by 18.42% and 60.25%, respectively, compared to EKB20 and 5% and 4% compared to diesel. The addition of 5% DEE and 10% DEE shows a 39% and 51% increase in NOX concentration and a 90% reduction in CO emission at the maximum brake power output. Hence, it is concluded that the fuels EKB20 + 5% DEE and EKB20 + 10% DEE can be used as alternative fuels for diesel engines.

Encapsulation of vitamin D3 using rhamnolipids-based nanostructured lipid carriers

This work had as main objective to encapsulate vitamin D3 (VD3) into nanostructured lipid carriers (NLCs) using rhamnolipids as surfactant. Glycerol monostearate and medium chain triglycerides with 2.625 % of VD3 were used as lipid materials. The three formulations of NLCs with VD3 (NLCs + VD3) were composed by 99 % of aqueous phase, 1 % of lipid phase and 0.05 % of surfactant. The difference between them was the ratio of solid:liquid in lipid phase. The NLCs + VD3 sizes ranged between 92.1 and 108.1 nm. The most stable formulation maintaining their caracteristics for 60 days at 4 °C. The NLCs + VD3 cytotoxicity demonstrated that concentrations of 0.25 mg/mL or lower up had a good biocompatibility in vitro. During the in vitro digestion, formulations with lower sizes and higher content on solid lipid had higher lipolysis rate and consequently higher VD3 bioaccessibility. The rhamnolipids-based NLCs are a good option for the encapsulation of VD3.

Injection of l-arginine or l-lysine before freezing delays the emulsifying and gelling properties deterioration of myofibrillar proteins of frozen porcine Longissimus lumborum muscle

This study aimed to investigate the effects of injecting l-arginine and l-lysine solution before freezing and after thawing on the emulsifying and gelling properties of myofibrillar proteins (MPs) of frozen porcine longissimus dorsi. The results showed that the pre-freezing injections were more effective in alleviating the decrease in emulsifying properties of MPs compared with the post-thawing injections, as evidenced by higher emulsion creaming index, oil droplet size, interfacial absorptive protein amount, and viscoelasticity. Additionally, the pre-freezing injections could effectively mitigate the damage to the gelling properties of MPs, as evidenced by the formation of a homogeneous and compact gel network with stronger water retention, strength and chemical forces, as well as a higher proportion of non-flowing water, whereas the post-thawing injections could not. These results demonstrated that the injection of l-arginine and l-lysine solution before freezing could delay freezing-induced damage to the emulsifying and gelling properties of MPs, keeping the processing characteristics of frozen porcine.

Synthesis of micron-sized magnetic agarose beads chelated with nickel ions towards the affinity-based separation of histidine-tagged/rich proteins

Developing high-performance magnetic particles for the effective separation and purification of target proteins has become an important topic in the area of biomedical research. In this work, a simple and novel strategy was proposed for fabricating magnetic Fe3O4@agarose-iminodiacetic acid-Ni microspheres (MAIN), which can efficiently and selectively isolate histidine-tagged/rich proteins (His-proteins). Based on the thermoreversible sol-gel transition of agarose, basic magnetic agarose microspheres were prepared through the inverse emulsion method, in which the emulsion contained agarose and amine-modified Fe3O4 nanoparticles. The size of the emulsion was controlled by the emulsification of a high-speed shear machine, which improved the specific surface area of MAIN. Subsequently, the amine-modified Fe3O4 nanoparticles were covalently crosslinked with agarose through epichlorohydrin, which could avoid leakage of the magnetic source during use and increase the stability of MAIN. The microsized MAIN exhibited a clearly visible spherical core-shell structure with a diameter range from 3.4 μm to 9.8 μm, and excellent suspension ability in aqueous solution. The maximum adsorption capacity of MAIN for histidine-rich bovine hemoglobin was 1069.2 mg g-1 at 35 °C, which was higher than those of commercialized and most reported magnetic agarose microspheres/nanoparticles. The MAIN showed excellent adsorption ability and selectivity toward His-proteins in a mixture of histidine-rich bovine serum albumin (BSA) and histidine-poor lysozyme (LYZ). When the amount of LYZ was 5-fold higher than that of BSA, the recovery of BSA reached 75.0%. To prove its practicability, MAIN was successfully employed for the enrichment of histidine-tagged RSV-F0 from the cell culture medium supernatant. According to the optimized conditions, MAIN could enrich approximately 0.1 mg of RSV-F0 from 1 mL of complex biological sample. Therefore, we believe that the novel MAIN could be applicable for efficient separation and purification of His-proteins from complex biological systems.

lactis Through Emulsification Coupled with External Gelation for the Development of Synbiotic Systems

Aim of this work was the development of integrated and complex encapsulating systems that will provide more efficient protection to the probiotic strain Bifidobacterium animalis subsp. lactis (BB-12) in comparison to the conventional plain alginate beads. Within the scope of this study, the encapsulation of BB-12 through emulsification followed by external gelation was performed. For this purpose, a variety of alginate-based blends, composed of conventional and novel materials, were used. The results demonstrated that alginate beads incorporating 1% carrageenan or 2% nanocrystalline cellulose provided great protection to the viability of the probiotic bacteria during refrigerated storage (survival rates of 50.3% and 51.1%, respectively), as well as in vitro simulation of the gastrointestinal tract (survival rates of 38.7 and 42.0%, respectively). The incorporation of glycerol into the formulation of the beads improved the protective efficiency of the beads to the BB-12 cells during frozen storage, increasing significantly their viability compared to the plain alginate beads. Beads made of milk, alginate 1%, glucose 5%, and inulin 2% provided the best results in all cases. The microstructure of beads was assessed through SEM analysis and showed absence of free bacteria on the surface of the produced beads. Consequently, the encapsulation of BB-12 through emulsification in a complex encapsulating system was proved successful and effective.

A comparative study on the encapsulation of black carrot extract in potato protein-pectin complexes

This manuscript reveals the effect of the emulsification step on the black carrot extract (BCE) stabilization by potato protein isolate (PPI)-citrus pectin (CP) coacervates. The effect of core-to-wall ratio and concentration of wall material were also investigated. This was the first attempt to compare the characteristics of emulsified core particles (ECP) and non-emulsified core particles (NECP) coated with complex coacervates. Potato protein was used as an encapsulating agent by complex coacervation for the first time, and it showed excellent characteristics for the encapsulation. Non-hygroscopic particles were produced with emulsification while most of NECPs were slightly hygroscopic. The mean particle diameter of powders ranged from 65.05 to 152.47 μm which is suitable with SEM micrographs. ECPs showed lower particle size values with increased wall concentration at the constant core-to-wall ratio. Encapsulation efficiency (EE) increased, and anthocyanin retention (AR) decreased when emulsification was included. EE of NECP and ECP was between 69.26-82.84% and 85.48-90.15% while AR was between 79.08-102.16% and 53.90-83.37%, respectively. FT-IR and ζ-potential values proved the complexation between PPI and CP in ECPs as well as the interaction of PP, CP, and BCE in NECPs. DSC thermograms proved the success of the encapsulation procedure and thermo-stability of the BCE-loaded particles.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-023-05787-z.

Experimental and numerical analysis of the emulsification of oil droplets in water with high frequency focused ultrasound

Focused high frequency ultrasound emulsification provides significant benefits such as enhanced stability, finer droplets, elevated focal pressure, lowered power usage, minimal surfactant usage and improved dispersion. Hence, in this study, the high frequency focused ultrasound emulsification of oil droplets in water was investigated through experiments and numerical modeling. The effect of transducer power (74-400 W), frequency (1.1 and 3.3 MHz), oil viscosity (10.6-512 mPas), interfacial tension (25-250 mN/m) and initial droplet radius (10-750 µm) on the emulsification process was assessed. In addition, the mechanism of droplet break-up was examined. The experiments showed that the acoustic pressure increased from 9.01 MPa to 26.24 MPa as the power was raised from 74 W to 400 W. At 74 W, the Weber number (We) at the surface and focal zone are 0.5 and 939.8, respectively. However, at 400 W, the We at the transducer surface and focal region reached 2.7 and 6451.8, respectively. Thus, bulb-like and weak catastrophic break up dominates the emulsification at 74 W. The catastrophic break up at 400 W is more vigorous because the ultrasound disruptive stress and We are higher. The time for the catastrophic dispersion of a single droplet at We = 939.8 and We = 6451.8 are 1.01 ms and 0.45 ms, respectively. The numerical model gives reasonable prediction of the trend and magnitude of the experimental acoustic pressure data. The surface and focal pressure amplitudes were estimated with errors of ∼ 6.5% and ∼ 10%, respectively. The predicted Reynolds number (Re) between 74 and 400 W were 8442 and 21364, respectively. The acoustic pressure at the focal region were ∼ 26 MPa and ∼ 69 MPa at frequencies of 1.1 MHz and 3.3 MHz, respectively. Moreover, the acoustic velocities were ∼ 16 m/s and ∼ 42 m/s at 1.1 MHz and 3.3 MHz, respectively. Hence, smaller droplets could be attained at higher frequency excitation under intense catastrophic modes. The Ohnesorge number (Oh) increased from 0.062 to 3.12 with the viscosity between 10.6 mPas and 530 mPas. However, the We remained constant at 856.14 for the studied range. Generally, higher critical We is required for the different breakup stages as the viscosity ratio is elevated. Moreover, the We increased from 25.68 to 1284.22 as the droplet radius was elevated from 15 to 750 µm. Larger droplets allow for higher possibility and intensity of breakup due to diminished viscous and interfacial resistance.

Characterization of trehalolipid biosurfactant produced by the novel marine strain Rhodococcus sp. SP1d and its potential for environmental applications

BACKGROUND

Biosurfactants are surface-active compounds with environmental and industrial applications. These molecules show higher biocompatibility, stability and efficiency compared to synthetic surfactants. On the other hand, biosurfactants are not cost-competitive to their chemical counterparts. Cost effective technology such as the use of low-cost substrates is a promising approach aimed at reducing the production cost. This study aimed to evaluate the biosurfactant production and activity by the novel strain Rhodococcus sp. SP1d by using different growth substrates. Therefore, to exploit the biosurfactant synthesized by SP1d for environmental applications, the effect of this compound on the bacteria biofilm formation was evaluated. Eventually, for a possible bioremediation application, the biosurfactant properties and its chemical characteristics were investigated using diesel as source of carbon.

RESULTS

Rhodococcus sp. SP1d evidence the highest similarity to Rhodococcus globerulus DSM 43954^T and the ability to biosynthesize surfactants using a wide range of substrates such as exhausted vegetable oil, mineral oil, butter, n-hexadecane, and diesel. The maximum production of crude biosurfactant after 10 days of incubation was reached on n-hexadecane and diesel with a final yield of 2.38 ± 0.51 and 1.86 ± 0.31 g L^- 1 respectively. Biosurfactants produced by SP1d enhanced the biofilm production of P. protegens MP12. Moreover, the results showed the ability of SP1d to produce biosurfactants on diesel even when grown at 10 and 18 °C. The biosurfactant activity was maintained over a wide range of NaCl concentration, pH, and temperature. A concentration of 1000 mg L^- 1 of the crude biosurfactant showed an emulsification activity of 55% towards both xylene and olive oil and a reduction of 25.0 mN m^- 1 of surface tension of water. Eventually, nuclear magnetic resonance spectroscopy indicated that the biosurfactant is formed by trehalolipids.

CONCLUSIONS

The use of low-cost substrates such as exhausted oils and waste butter reduce both the costs of biosurfactant synthesis and the environmental pollution due to the inappropriate disposal of these residues. High production yields, stability and emulsification properties using diesel and n-hexadecane as substrates, make the biosurfactant produced by SP1d a sustainable biocompound for bioremediation purpose. Eventually, the purified biosurfactant improved the biofilm formation of the fungal antagonistic strain P. protegens MP12, and thus seem to be exploitable to increase the adherence and colonization of plant surfaces by this antagonistic strain and possibly enhance antifungal activity.

Regulation mechanism of curcumin-loaded oil on the emulsification and gelation properties of myofibrillar protein: Emphasizing the dose-response of curcumin

The regulation mechanism of curcumin (CUR) in the oil phase on the emulsification and gelation properties of myofibrillar protein (MP) was investigated. CUR enhanced the emulsifying activity index (EAI) of MP but decreased its turbiscan stability index (TSI) and surface hydrophobicity, which exacerbated oil droplet aggregation. Medium amounts (200 mg/L) of CUR changed the 3D network architectures of emulsion gels from lamellar to reticular, improving the gels' water-holding capacity (WHC), storage modulus, springiness, and cohesiveness. Besides, the LF-NMR revealed that CUR had limited effects on the mobility of immobilized and free water. The α-helix of MP in gels with medium amounts of CUR decreased from 51% to 45%, but the β-sheet increased from 23% to 27% compared to those without CUR. Overall, CUR has the potential to become a novel structural modifier in emulsified meat products due to its dose-response.

Mesoporous carbon hollow spheres encapsulated phase change material for efficient emulsification of high-viscosity oil

Low fluidity of high-viscosity oil usually hinders its emulsification. Facing this dilemma, we proposed a novel functional composite phase change material (PCM) with in situ heating feature coupled with emulsification capability. This composite PCM consisting of mesoporous carbon hollow spheres (MCHS) and polyethylene glycol (PEG) shows excellent photothermal conversion ability, thermal conductivity and Pickering emulsification. Compared with the currently reported composite PCMs, the unique hollow cavity structure of MCHS not only enables excellent encapsulation of PCM, but also protects the PCM from leaking and direct contact with oil phase. Importantly, the thermal conductivity of 80% PEG@MCHS-4 was determined to be 1.372 W/m·K, which was 2.887 times superior to that of pure PEG. MCHS endows the composite PCM with excellent light absorption capacity and photothermal conversion efficiency. The viscosity of high-viscosity oil can be facilely reduced in situ once it comes into contact with the heat-storing PEG@MCHS, thus the emulsification is greatly enhanced. In view of the in situ heating feature and emulsification capability of PEG@MCHS, this work puts forward a novel solution to address the problem of emulsification of high-viscosity oil through the integration of MCHS and PCM.

Surface and bulk mechanisms in repeating treatment of solid surfaces by purified water

To decrease the negative impact of surfactants, the idea of using purified water in washing has been proposed. Previous studies showed that purified water facilitates the roll-up mechanism by promoting electrostatic interactions between the surface and the soil. However, washing mechanisms can be dependent on the amount of remaining soil. In this work we studied the removal of thin Vaseline films and thicker oil films from hydrophilic surfaces using multiple washing cycles at different temperatures. The Quartz Crystal Microbalance with Dissipation monitoring (QCM-D) and gravimetric analysis were used for thin and thick films respectively. In QCM-D experiments most of the thin film was removed during the first two cycles, while following cycles did not substantially affect washing efficiency; increased temperature facilitated the washing process. Gravimetric analysis showed that the washing of thicker films can be divided into two regimes. During the first, exponential, regime the amount of oil on the surface is high and surface mechanisms, such as roll-up, dominate. Oil droplets are kinetically stabilized in purified water by electrostatic interactions. As the amount of oil on the surface decreases, the second, linear, regime is introduced. The removal of oil occurs by equilibrium bulk mechanisms, where electrostatic interactions are less important.

Effects of multi-frequency ultrasound on sodium caseinate/pectin complex: Emulsifying properties, interaction force, structure and correlation

This study aimed to improve the emulsification properties of the sodium caseinate (Cas) and pectin (Pec) complex using multi-frequency power ultrasound to regulate the complexation of Cas and Pec. The results revealed that optimal ultrasonic treatment (Frequency 60 kHz, power density 50 W/L, and time 25 min) led to a 33.12 % increase in emulsifying activity (EAI) and a 7.27 % increase in emulsifying stability index (ESI) of the Cas-Pec complex. Our results demonstrated that electrostatic interactions and hydrogen bonds were the main driving forces for complex formation, and these were reinforced by ultrasound treatment. Moreover, it was observed that ultrasonic treatment improved the surface hydrophobicity, thermal stability, and secondary structure of the complex. Scanning electron microscopy and atomic force microscopy analyses revealed that the ultrasonically prepared Cas-Pec complex had a dense, uniform spherical structure with reduced surface roughness. It was further confirmed that the complex's emulsification properties were highly correlated with its physicochemical and structural properties. Multi-frequency ultrasound changes the interaction by regulating protein structure and ultimately acting on the interfacial adsorption behavior of the complex. This work contributes to expanding the role of multi-frequency ultrasound in modifying the emulsification properties of the complex.

Synthesis of octenyl succinic anhydride-modified levan and investigation of its microstructural, physicochemical, and emulsifying properties

In this study, levan from Bacillus licheniformis NS032 was modified in an aqueous medium by octenyl succinic anhydride (OSA), and the properties of the obtained derivatives were studied. The maximum efficiency in the synthesis reaction was achieved at 40 °C and a polysaccharide slurry concentration of 30 %. Increasing the reagent concentration (2-10 %) led to an increase in the degree of substitution (0.016-0.048). Structures of derivatives were confirmed by FTIR and NMR. Scanning electronic microscopy, thermogravimetry, and dynamic light scattering analyses showed that the derivatives with degrees of substitution of 0.025 and 0.036 retained levan's porous structure and thermostability and showed better colloidal stability than the native polysaccharide. The intrinsic viscosity of derivatives increased upon modification, while the surface tension of the 1 % solution was lowered to 61 mN/m. Oil-in-water emulsions prepared with sunflower oil (10 % and 20 %) by mechanical homogenization and 2 and 10 % derivatives in the continuous phase showed mean oil droplet sizes of 106-195 μm, while the distribution curves exhibited bimodal character. The studied derivatives have a good capacity to stabilize emulsions, as they have a creaming index ranging from 73 % to 94 %. The OSA-modified levans could have potential applications in new formulations of emulsion-based systems.

Identification of emulsification proteins released from the cells by inhibiting the synthesis of GPI-anchor or β-1,3-glucan in Candida albicans

INTRODUCTION

A previous study demonstrated a strong emulsification ability of the culture supernatant obtained by cultivation of Candida albicans in a medium containing a β-1,3-glucan synthesis inhibitor and proposed a novel screening method using emulsification as an indicator for β-1,3-glucan synthesis inhibition (Nerome et al., 2021. Evaluating β-1,3-glucan synthesis inhibition using emulsion formation as an indicator. J Microbiol Methods. 190:106327). The emulsification was presumed to be caused by the proteins released from the cells; however, which proteins have a strong emulsification ability was unclear. Furthermore, as many cell wall proteins are connected to β-1,3-glucan via the carbohydrate moiety of the glycosylphosphatidylinositol (GPI)-anchor, which remains when detached from the cell membrane, emulsification might be detected by inhibiting GPI-anchor synthesis.

OBJECTIVE

This study aimed to confirm whether emulsification could be detected by inhibiting GPI-anchor synthesis and identifying emulsification proteins released by inhibiting the synthesis of GPI-anchor or β-1,3-glucan.

METHODS

C. albicans was cultured in a medium containing a GPI-anchor synthesis inhibitor, and the emulsification by the culture supernatant was evaluated. We identified cell wall proteins released from the cells upon inhibition of β-1,3-glucan or GPI-anchor synthesis by mass spectrometry, their recombinant proteins were prepared, and their emulsification efficacy was evaluated.

RESULTS

In GPI-anchor synthesis inhibition, a weak emulsification phenomenon was observed compared to the β-1,3-glucan synthesis inhibition. Phr2 protein was released from the cells upon GPI-anchor synthesis inhibition, and recombinant Phr2 showed a strong emulsification activity. Phr2 and Fba1 proteins were released upon β-1,3-glucan synthesis inhibition, and recombinant Fba1 showed a strong emulsification activity.

CONCLUSIONS

We concluded that the emulsion phenomenon could be used to screen β-1,3-glucan and GPI-anchor synthesis inhibitors. Also, the two kinds of inhibitors could be distinguished by differences in the growth recovery by osmotic support and strength of emulsification. In addition, we identified the proteins involved in emulsification.

Emulsions containing composite (clove, oregano, and cinnamon) essential oils: Phase inversion preparation, physicochemical properties and antibacterial mechanism

Natural essential oils (EOs), especially those combining different individual EOs (also termed composite EOs) with enhanced performance, are becoming healthy, market-sought food preservatives/additives. This study aims to provide insights into the challenge regarding EOs processing due to their low solubility and the elusive mechanism under the enhanced bio-reactivity of composite EOs. A unique oil/water interacting network was created by phase-inversion processing, which enhances EO solubilization and emulsification to form composite EO formulations (EOFs) containing ordinary cinnamon, oregano and clove EOs. These EOFs mainly contained cinnamaldehyde, carvacrol and eugenol and exhibited excellent post-storage stability. The 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging ability of EOFs (at 15.880 μL/mL) was > 88%, and the Ferric reducing antioxidant power (FRAP) was 1.8 mM FeSO₄·7H₂O. The minimum inhibitory concentration (MIC) of EOFs against E. coli and S. aureus was ∼7.940 μL/mL. The EOFs could cause quick deterioration of bacterial structures, demonstrating high efficacy in bacteria-killing and anti-biofilm formation.

Emulsification mechanism in an ultrasonic microreactor: Influence of surface roughness and ultrasound frequency

An ultrasonic microreactor with rough microchannels is presented in this study for oil-in-water (O/W) emulsion generation. Previous accounts have shown that surface pits or imperfections localize and enhance cavitation activity. In this study cavitation bubbles are localized on the rough microchannels of a borosilicate glass microreactor. The cavitation bubbles in the microchannel are primarily responsible for emulsification in the ultrasonic microreactor. We investigate the emulsification mechanism in the rough microchannels employing high-speed imaging to reveal the different emulsification modes influenced by the size and oscillation intensity of the cavitation bubbles. The effect of emulsification modes on the O/W emulsion droplet size distribution for different surface roughness and frequency is demonstrated. The positive effect of the frequency on minimizing the droplet size utilizing a reactor with large pits is presented. We also demonstrate microreactor systems for a successful generation of miniemulsions with high dispersed phase volume fractions up to 20%. The observed emulsification mechanism in the rough microchannel offers new insights into the utility and scale-up of ultrasonic microreactors for emulsification.

Effect of single and dual modifications with cross-linking and octenylsuccinylation on physicochemical, in-vitro digestibility, and emulsifying properties of cassava starch

Native cassava starch (NCS) was chemically modified by cross-linking (CL), octenylsuccinylation (OS), CL followed by OS, and OS followed by CL. The modified cassava starches (MCS) were determined for physicochemical, in-vitro digestibility, and emulsifying properties. For the dual modifications, the functional groups introduced in the first modification were partially replaced by the ones that introduced in the second modification. The X-ray diffraction pattern and relative crystallinity of cassava starch did not change by both modifications, indicating that both reactions occurred predominantly in amorphous regions as well as on the surface of starch granules and did not alter the crystalline pattern in the granules. The physicochemical and emulsifying properties of the dual MCS were predominantly affected by the functional groups introduced in the second modification. For the in-vitro digestibility, the dual MCS exhibited the highest resistant starch content of 19.48-22.00% in comparison with the NCS (6.05%) and the single MCS (10.76-14.49%), possibly due to a synergistic effect of the functional groups introduced in the first and second modifications.

Biomolecules from Serratia sp. CS1 indigenous to Ethiopian natural alkaline lakes: biosurfactant characteristics and assessment of compatibility in a laundry detergent

In this study, the biosurfactants (Bio-SFs) producing bacteria are screened from the selected alkaline lake of Ethiopia, and the potential bacterial strain and their produced Bio-SFs are further characterized. In an initial screening, 25 bacterial isolates were isolated, and among those, the bacterial isolate assigned as CS1 was identified as the most potent producer of Bio-SFs using a subsequent characterization process. The CS1 strain was identified as Serratia sp. via biochemical and molecular methods. An emulsion index (E₂₄) of 69.06 ± 0.11% was obtained for CS1 after 5 days of incubation time at 30 °C. The CS1-extracted Bio-SFs were characterized by Fourier transform infrared (FTIR), and it indicated that the type of biosurfactant produced was a glycolipid. The stability of the crude Bio-SFs was characterized, and the optimal conditions were found to be 80 °C, pH 8, and 3% NaCl, respectively. The extracted Bio-SFs were compatible with tested commercial detergents, and its efficiency increased from 12.2 ± 0.1% to 67.1 ± 0.17% and 70.43 ± 0.11% when combined with commercially available detergent brands in Ethiopia such as Taza and Largo, respectively. This study suggests that the isolated S. marcescens CS1 strain has the potential to produce Bio-SFs that are viable competence to replace the use of synthetic chemicals in the production of commercial detergents.

Cost-effective rhamnolipid production by Burkholderia thailandensis E264 using agro-industrial residues

The agro-industrial by-products corn steep liquor (CSL) and olive mill wastewater (OMW) were evaluated as low-cost substrates for rhamnolipid production by Burkholderia thailandensis E264. In a culture medium containing CSL (7.5% (v/v)) as sole substrate, B. thailandensis E264 produced 175 mg rhamnolipid/L, which is about 1.3 times the amount produced in the standard medium, which contains glycerol, peptone, and meat extract. When the CSL medium was supplemented with OMW (10% (v/v)), rhamnolipid production further increased up to 253 mg/L in flasks and 269 mg/L in a bioreactor. Rhamnolipids produced in CSL + OMW medium reduced the surface tension up to 27.1 mN/m, with a critical micelle concentration of 51 mg/L, better than the values obtained with the standard medium (28.9 mN/m and 58 mg/L, respectively). However, rhamnolipids produced in CSL + OMW medium displayed a weak emulsifying activity when compared to those produced in the other media. Whereas di-rhamnolipid congeners represented between 90 and 95% of rhamnolipids produced by B. thailandensis E264 in CSL and the standard medium, the relative abundance of mono-rhamnolipids increased up to 55% in the culture medium containing OMW. The difference in the rhamnolipid congeners produced in each medium explains their different surface-active properties. To the best of our knowledge, this is the first report of rhamnolipid production by B. thailandensis using a culture medium containing agro-industrial by-products as sole ingredients. Furthermore, rhamnolipids produced in the different media recovered around 60% of crude oil from contaminated sand, demonstrating its potential application in the petroleum industry and bioremediation. KEY POINTS: • B. thailandensis produced RL using agro-industrial by-products as sole substrates • Purified RL displayed excellent surface activity (minimum surface tension 27mN/m) • Crude RL (cell-free supernatant) recovered 60% of crude oil from contaminated sand.

Influences of specific surfactant structures on biohydrogen production from oily wastewater in batch and continuous anaerobic dark fermentation

Residual oil in palm oil mill effluent (POME) poses difficulties in its treatment chain. Non-ionic surfactants containing different hydrophobic tail structures and their optimal concentrations were evaluated for effectiveness in biohydrogen production. By adding the surfactants at their critical micelle concentration in synthetic oily wastewater, the maximal H₂ yield was increased by 2.2 and 3.5 times for Triton X-100 and Tergitol 15-S-9, respectively, compared to the control. Using real POME, the supplemental Tergitol 15-S-9 resulted in a 56.4 % improvement in H₂ production. For continuous digestion studies, pure POME and Tergitol 15-S-9 supplemented POME (sPOME) were fed to thermophilic anaerobic sequencing batch reactors (ASBRs) under hydraulic retention time (HRT) of 32-12.5 days. Optimally at HRT 19 days, H₂ content in the biogas from sPOME-fed ASBR was noticeably higher, which gave a superior yield of 203.4 mLH₂/gCOD_removed (+15 %).

Development and application of hydrophilic-hydrophobic dual-protein Pickering emulsifiers: EGCG-modified caseinate-zein complexes

Zein nanoparticles are commonly used as colloidal emulsifiers to form and stabilize Pickering emulsions. However, the strong surface hydrophobicity of zein nanoparticles limits their widespread application. In this study, composite colloidal emulsifiers were fabricated from zein, sodium caseinate (NaCas), and epigallocatechin gallate (EGCG). Initially, NaCas-EGCG conjugates were formed using either an alkaline or enzymatic method. The enzymatic method led to conjugates containing more EGCG and with a higher thermal stability and surface hydrophilicity. Colloidal emulsifiers were prepared using an antisolvent precipitation method that involved titrating an ethanolic zein solution into an aqueous NaCas-EGCG conjugate solution. The potential application of these emulsifiers for forming and stabilizing high internal phase emulsions (HIPEs) was then explored. The emulsification properties of the zein nanoparticles were improved after they were complexed with NaCas-EGCG conjugates. Pickering HIPEs containing closely packed polygon oil droplets were formed from the colloidal emulsifiers, even at low particle concentrations (0.3% w/v). Overall, our results show that the functional performance of zein nanoparticles can be improved by complexing them with NaCas-EGCG conjugates. The novel colloidal emulsifiers developed in this study may therefore have useful applications in the food and other industries.

Emulsifying and emulsion stabilizing properties of hydrolysates of high-density lipoprotein from egg yolk

High-density lipoprotein (HDL) was extracted from hen eggs and enzymatic hydrolysates were formed by neutral protease, trypsin and alkaline protease, which were named as EHN, EHT and EHA, respectively. The solubility of hydrolysates was significantly higher than that of HDL, especially that of EHA significantly increased from 7.69% to 27.54% when it was hydrolyzed for 1.5 h. The emulsifying properties of EHT, EHA and EHN exhibited an increase trend as a function of hydrolysis time and reached the peak values at 3.5, 1.5 and 3.5 h, respectively. This improvement was attributed to the generation of soluble peptides fragments and the exposure of ionizable residues. At different pH, temperatures and ionic strengths, the stability of emulsions stabilized by hydrolysates was higher than that of HDL, especially for emulsions prepared by EHT. These findings might indicate feasible guidance to broaden the application of HDL and enzymatic hydrolysates in emulsions.

Recent progress in oil-in-water-in-oil (O/W/O) double emulsions

Oil-in-water-in-oil (O/W/O) double emulsions are recognized as an advanced design route for oil structuring that shows promising applications in the pharmaceutical, cosmetic, and food fields. This review summarizes the main research advances of O/W/O double emulsions over the past two decades. It mainly focuses on understanding the preparation strategies, stabilization mechanism, and potential applications of O/W/O double emulsions. Several emulsification strategies are discussed, including traditional two-step emulsification method, phase-inversion approach, membrane emulsification, and microfluidic emulsification. Further, the role of interfacial stabilizers and viscosity in the stability of O/W/O double emulsions will be discussed with a focus on synthetic emulsifiers, natural biopolymer sand solid particles for achieving this purpose. Additionally, analytical methods for evaluating the stability of O/W/O double emulsions, such as advanced microscopy, rheology, and labeling assay are reviewed taking into account potential limitations of these characterization techniques. Moreover, possible innovative food applications are highlighted, such as simulating fat substitutes to decrease the trans- or saturated fatty acid content and developing novel delivery and encapsulation systems. This review paves a solid way for the exploration of O/W/O double emulsions toward large-scale implementation within the food industry.

A biogenic microbial biosurfactin that degrades difenoconazole fungicide with potential antimicrobial and oil displacement properties

Surfactin is a bacterial lipopeptide and an influential biosurfactant mainly known for excellent surfactant ability. The amphiphilic nature of surfactin helps it to sustain under hydrophobic and hydrophilic conditions. In this investigation, a bacterium strain (BTKU3) that produces biosurfactant were isolated from oil-contaminated soil. Based on the blue agar plate (Bap) assay, the BTKU3 strain was found to be promising for biosurfactant production. This strain was later identified as a Lysinibacillus sp. by 16S rRNA sequencing. The characteristics of extracted bacterial surfactin were evidenced by FTIR with the presence of amine, C-H, CO, CC, esters, thiocarbonyl and asymmetric aliphatic C-H stretch molecular structural groups. Further, the extracted bacterial biosurfactant material was subjected to Liquid Chromatography-Mass Spectroscopy (LCMS), and it was identified and confirmed as surfactin with an elution time of 3.1 min and m/z value of 1034. The emulsification and oil displacement tests further proved the surfactin ability with 83% of coconut oil emulsion index and 80 % oil displacement ability with diesel, respectively. Lysinibacillus sp. BTKU3 strain also proved its efficacy in the degradation of difenoconazole by utilizing a capacity of 9.1 μg ml^-1. Thus, it is inferred that the Lysinibacillus sp. BTKU3 strain plays a significant role in the production of surfactin, which positively acts as an antimicrobial agent and reduces contaminants in polluted sites.

Optimization of heavy metal (lead) remedial activities of fungi Aspergillus penicillioides (F12) through extra cellular polymeric substances

Wastewater imposes a great threat to any ecosystem across the world, especially the aquatic one because of the different anthropogenic activities of human beings. The present study emphasizes the optimization of ecological parameters [pH, time (h) and temperature (°C)] employing Box-Behnken design (BBD) to achieve better bio-adsorption of a selected heavy metal [lead (Pb II)] from the wastewater through an extracellular polymeric substance (EPS) of a benthic fungus, Aspergillus penicillioides (F12) (MN210327). The relevant statistical analysis (ANOVA) has enabled to record of the optimized bio-adsorption (73.14 %) of lead (Pb II) by fungal EPS at pH (8.85) and temperature (32 °C) for a duration of 5.74 h. Besides that, at the concentration of 0.5 mg/L of EPS, the flocculating rate was noted to be highest (88.4 %) in kaolin clay and the 50 % emulsifying activity. This investigation has also opened up new vistas on the possibility of the development of an alternative method of eco-sustainable bioremediation of heavy metals by fungal EPS on an industrial scale.

The pH dependence of emulsifying properties for glutathione disulfide at oil-water interfaces

Although peptides were widely used in many fields, their interface behaviors as surfactants have not been explored. The results of the surface tension experiments by an automatic surface tension meter indicate that the stability and emulsifying ability of glutathione disulfide (GSSG) under alkaline conditions were stronger than those under acidic conditions. With encoding the different oxygen and nitrogen atoms in GSSG, as well as the different hydrogen atoms bonded with oxygen and nitrogen atoms. The pH Dependence of the number of hydrogen bonds, affected by the protonation and deprotonation of the functional groups in GSSG, is calculated by LAMMPS software. The results demonstrate that GSSG forms twice as many hydrogen bonds under alkaline conditions as under acidic conditions, resulting in a better surface-interface activity in alkaline conditions. The interface properties of the GSSG surfactant can be regulated by pH. Therefore, GSSG is a potential pH-responsive surfactant.

Characterization and cytotoxicity assessment of biosurfactant derived from Lactobacillus pentosus NCIM 2912

Noteworthy properties of biosurfactant (BS) are fascinating scientific fraternity to explore them for food, medicinal, cosmetic, or pharmaceutical etc. applications. Newer products intended for pharmaceutical purposes are mandatory to go through pragmatic evaluation protocols. BS, being less cytotoxic, offers an ideal candidature for widespread applications in the healthcare sector. The goal of the current study was the isolation, physico-chemical characterization, and safety assessment of cell-associated biosurfactant (CABS) from Lactobacillus pentosus NCIM 2912. The culture was grown in a 3-L fermentor to produce CABS from the cell pellets through procedures like centrifugation, filtration, dialysis, column chromatography, and freeze-drying. Further, physical properties like surface tension (ST), critical micelle concentration (CMC), contact angle (CA), emulsification activity, stability of emulsion (height of emulsion, the extent of coalescence, and appearance), and ionic character of CABS were evaluated. Analytical characterization through TLC, FTIR, NMR, and GC-MS was carried out. The physico-chemical characterization revealed CABS as an anionic, multicomponent glycolipopeptide having a hydrophobic chain comprising butanoic acid (C4), decanoic acid (C10), undecanoic acid (C11), tridecanoic acid (C13), hexadecenoic acid (C16), and octadecanoic acid (C18). The oil-in-water (O/W) emulsions formed by CABS with various oils (olive, sesame, soybean, coconut) were stabilized up to the 7th day of storage and were analogous with polysorbate 80 (emulsifier/defoamer used in food industries). The O/W emulsions are quite stable at room temperature with no evidence of coalescence of droplets around 1 week. The cytotoxicity of CABS was evaluated through MTT (3-(4,5-dimethylthiazole-2-yl)-2,5-diphenyltetrazolium bromide) assay. Cytotoxicity study performed on the human embryonic kidney (HEK 293), mouse fibroblast ATCC L929 and human epithelial type (HEP-2) cell lines recorded viability of 90.3 ± 0.1%, 99.2 ± 0.43, and 94.3 ± 0.2% respectively. The toxicity of the BS was comparable to that of the commercially used rhamnolipid sample. Thus, CABS derived from L. pentosus NCIM 2912 pose promising applications in the pharmaceutical, food industries acquiescently. The multifunctional potential of the incredibly versatile microbial product like BS from lactic acid bacteria (LAB) certainly contributes to wider avenues for varied industries.

Assessment of Rheological Behaviour of Water-in-Oil Emulsions Mediated by Glycolipid Biosurfactant Produced by Bacillus megaterium SPSW1001

A screening programme using mineral salt medium supplemented with n-hexadecane resulted in isolating a Bacillus megaterium SPSW1001 which was capable of producing surface active molecules lowering culture medium surface tension to 27.43 ± 0.029 mN/m and interfacial tension to 0.38 ± 0.03 mN/m at 72 h and an emulsification index (E₂₄) (85.63%). The biosurfactant product was further used to assess its effects on the rheological characteristics of water-in-oil emulsion prepared with engine oil. Structural characterization of the biosurfactant product by FTIR revealed a C-O-C stretch in sugar moiety and ester carbonyl linkage group between sugar and fatty acids, respectively, while mass spectral analysis revealed its glycolipid nature, with an m/z value of 662.44. The fluid behaviour of water-in-oil emulsion showed a non-Newtonian viscoelastic dilatant flow after yielding exemplified appropriately by Herschel-Bulkley model with 100% confidence of fit. The present study is significant in formulation and handling, processing, and transport of emulsion and in understanding flocculation characteristics.

Extraction and characterization of an exopolysaccharide from a marine bacterium

The marine bacterial exopolysaccharides (EPS) have transfigured the biotech sector with their myriad applications and prospects. This work was carried out to characterize and analyze the functional and biochemical properties of an EPS (EPS-DR3A) produced by a marine bacterium, Pseudoalteromonas sp. YU16-DR3A. The bacterium was cultured in Zobell marine broth for the production of EPS. The extracted EPS designated as EPS-DR3A was composed of 69% carbohydrates and 7.6% proteins with a molecular weight of 20 kDa. FT-IR spectra showed the presence of different functional groups. The monosaccharide analysis performed using GC-MS showed the presence of fucose, erythrotetrose, ribose, and glucose as monomers. EPS-DR3A showed excellent emulsifying activity against the tested hydrocarbons and food oils with stable emulsions. Rheological analysis of EPS-DR3A revealed the pseudoplastic behavior. The EPS-DR3A displayed good thermal stability with a degradation temperature of 249 °C and a melting point at 322 °C. Further, it had the ability to scavenge DPPH and nitric oxide free radicals with good total antioxidant activity. The in vitro biocompatibility study of EPS-DR3A showed high degree of biocompatibility with human dermal fibroblast cells at the tested concentrations. Taken together, the findings such as thermostability, emulsifying activity, pseudoplasticity, antioxidant activity, and biocompatibility of EPS-DR3A make this biomolecule an important candidate for a wide range of biomedical applications.

Quality by design enabled the development of stable and effective oil-in-water emulsions at compounding pharmacy: the case of a sunscreen formulation

It is widely accepted that the use of topical sunscreens has medical importance with potential to prevent skin damage by protecting from solar ultraviolet radiation (UVR) effects. Pharmaceutical emulsions require an optimal qualitative and quantitative combination of emollients, emulsifiers and others compounds such as softening agents and, for sunscreens, a combination of chemical and physical UV filters. Herein, we applied the quality by design (QbD) concept to achieve stable and effective compounded sunscreen emulsions. By using the statistical tool of design of experiments, it was possible to identify the influence of emulsifier type (with low and high Hydrophile-Lipophile Balance) and concentrations of emollient and softening agent on the achievement of formulations with suitable organoleptic and physicochemical features. Compounded emulsions with pleasant macroscopic aspects were obtained. Three formulations with physicochemical properties in targeted ranges were selected, namely pH ∼6.0, conductivity > 0.0 µS/cm², spreadability factor ∼1-1.5 g/mm², viscosity ∼12000 mPa.s and sunscreen protection factor ∼30. Freeze-thaw cycle and accelerated stability study under different storage conditions allowed selecting a stable emulsion that ensured photoprotection in biological assays. The QbD approach was essential to select the best, low-cost compounded sunscreen emulsion, with targeted physicochemical parameters.

Evaluating β-1,3-glucan synthesis inhibition using emulsion formation as an indicator

INTRODUCTION

The cell wall β-1,3-glucan of fungal pathogen Candida albicans is an attractive antifungal target. β-1,3-Glucan is the skeletal structure in the cell wall and the major scaffold for cell wall proteins. In previous studies using Saccharomyces cerevisiae, strong emulsification was detected by mixing cell wall proteins with oil. To date, there have been no reports of applying an emulsification phenomenon to assessing β-1,3-glucan synthesis inhibition.

OBJECTIVE

The aim of this study was to clarify that emulsification is useful as an indicator for evaluating β-1,3-glucan synthesis inhibition in C. albicans.

METHODS

At first, whether cell wall proteins released from cells by β-1,3-glucanase treatment worked as an effective emulsifier in C. albicans was examined. Next, whether emulsification occurred even in the culture supernatant brought about by treating with bioactive compounds, including β-1,3-glucan synthesis inhibitors, under osmotic protection was investigated. In addition, the release of cell wall proteins into the culture medium by treating with those compounds was examined. Finally, a simpler evaluation method using emulsion formation was examined for application to screening of inhibitors.

RESULTS

Emulsification occurred by cell wall proteins obtained by treating with β-1,3-glucanase in C. albicans. In addition, cell wall proteins were released into the culture medium by treating with β-1,3-glucan synthesis inhibitors, resulting in emulsification. However, such phenomena were not observed in the case of other bioactive compounds. Furthermore, emulsification could be detected in the culture broth obtained by static culture on a small scale.

CONCLUSIONS

The obtained results strongly implied that emulsification results from decreased β-1,3-glucan levels in the cell wall. As emulsification can be simply evaluated by mixing the culture broth with oil, in the future application to the initial assessment and screening of β-1,3-glucan synthesis inhibitors is expected.

Investigation of the flowability, thermal stability and emulsification properties of two milk protein concentrates having different levels of native whey proteins

Milk protein concentrate-85 (MPC85) is a dairy ingredient which has a diverse range of applications in food products. The technofunctional properties of two MPC85 samples having similar gross composition but different levels of native whey protein (WP), i.e., MPC85S1 and MPC85S2 with 16.6 and 6.0 g native WP/100 g protein, respectively, were compared. Rheometeric analysis showed that under an applied normal stress of 1.0-15.0 kPa, the compressibility, the air permeability and the cohesiveness of MPC85S2 was higher compared to MPC85S1. Differential scanning calorimetry showed that protein denaturation in MPC85S1 began at 63 °C while for MPC85S2 it began at 70 °C. The heat coagulation time (HCT at 140 °C) for 4.2% (w/v, on a protein basis) reconstituted MPC85S1 and MPC85S2 was 2.2 and 2.7 min, respectively. While a higher lightness for MPC85S1 was evidenced using colourimeter analysis, the colour stability on oven drying at 95 °C for MPC85S2 was higher than MPC85S1. The emulsion produced with MPC85S1 flocculated after 1 d and phase separation occurred after 14 d. In the case of MPC85S2, flocculation began after 4 d while phase separation was observed at 33 d. The viscosity of MPC85S2 (4.2% (w/v) protein) was higher than MPC85S1. This study showed differences between the flowability, viscosity, colour properties, thermal stability (in powder and in reconstituted format), emulsification and buffering capacity for MPC samples having two different levels of WP denaturation. The results demonstrated that the MPCs studied having two different levels of WP denaturation could be targeted for different functional applications. The minimal/maximum level of denaturation required to induce technofunctional property differences requires further study.

A novel n-3 glyceride mixture enhances enrichment of EPA and DHA after single dosing in healthy older adults: results from a double-blind crossover trial

A glyceride mixture of monoglyceride, diglyceride and TAG increases solubilisation and enhances emulsification of n-3 fatty acid (FA)-containing lipids in the stomach. This allows for better access of digestive enzymes, pivotal for the release of bioactive n-3 FA. The objective was to compare the effect of a glyceride formulation and an ethyl ester formulation of EPA + DHA on concentrations of EPA and DHA in plasma following single dosing. We conducted a double-blind crossover trial in which twenty healthy adults aged 50-70 years consumed a single dose (2·8 g EPA + DHA) of each EPA + DHA formulation without a meal in random order separated by a 2-week washout period. EPA and DHA were measured in plasma total lipid over the following 12 h. EPA and DHA in plasma total lipid increased over 12 h with both formulations. A 10-fold greater Δ concentration of EPA, 3-fold greater Δ concentration of DHA and 5-fold greater Δ concentration of EPA + DHA were seen with the glyceride-EPA + DHA. The time at which the maximal concentrations of n-3 FA occurred was 4 h earlier for EPA, 1 h earlier for DHA and 2 h earlier for EPA + DHA when consuming glyceride-EPA + DHA. A mixture of monoglyceride, diglyceride and TAG results in greater and faster incorporation of EPA and DHA into blood plasma lipid in the absence of a fatty meal. This may provide benefit to individuals on a low-fat diet or with digestive impairments and could result in greater efficacy in clinical trials using n-3 FA.

l-Theanine improves emulsification stability and antioxidant capacity of diacylglycerol by hydrophobic binding β-lactoglobulin as emulsion surface stabilizer

Diacylglycerol (DAG) is commonly used as fat substitute in food manufacture due to its functional properties, but DAG has poor emulsification and oxidation stability, which limits its wide application in food industry. In this work, fluorescence quenching data and thermodynamic parameters were analyzed to investigate the interaction mechanism between l-theanine (L-Th) and β-lactoglobulin (β-LG). DAG emulsion was prepared by using β-lactoglobulin-theanine (β-LG-Th) as surface stabilizer, and its emulsification and oxidation stability were evaluated. The results showed that the hydrophobic interaction played an important role on the conjugate of β-LG and L-Th due to the negative values for ΔG, positive values for ΔH and ΔS at pH 4.0, pH 6.0 and pH 8.0. The DAG has been better embedded by using β-LG-Th as surface stabilizer, and the droplet size was about 0.2 µm to 1.5 µm when the pH was 6.0, the ratio of L-Th to β-LG was 1:1. β-LG-Th as surface stabilizer for DAG can increase the ζ-potential and emulsion index, make the emulsion droplet size distribution more uniform. The l-theanine was better to be used to improve the emulsification stability and antioxidant capacity of DAG by binding β-LG as surface stabilizer.