Oil Bodies Research Articles

Analysis of oil synthesis pathway in Cyperus esculentus tubers and identification of oleosin and caleosin genes

The tubers of the widely distributed Cyperus esculentus are rich in oil, and therefore, the plant is considered to have a high utilization value in the vegetable oil industry. Oleosins and caleosins are lipid-associated proteins found in oil bodies of seeds; however oleosins and caleosins genes have not been identified in C. esculentus. In this study, we performed transcriptome sequencing and lipid metabolome analysis of C. esculentus tubers at four developmental stages to obtain the information on their genetic profile, expression trends, and metabolites in oil accumulation pathways. Overall, 120,881 non-redundant unigenes and 255 lipids were detected; 18 genes belonged to the acetyl-CoA carboxylase (ACC), malonyl-CoA:ACP transacylase (MCAT), β-ketoacyl-ACP synthase (KAS), and fatty acyl-ACP thioesterase (FAT) gene families involved in fatty acid biosynthesis, and 16 genes belonged to the glycerol-3-phosphate acyltransferase (GPAT), diacylglycerol acyltransferase 3 (DGAT3), phospholipid:diacylglycerol acyltransferase (PDAT), FAD2, and lysophosphatidic acid acyltransferase (LPAAT) gene families playing important roles in triacylglycerol synthesis. We also identified 9 oleosin- and 21 caleosin-encoding genes in C. esculentus tubers. These results provide detailed information on the C. esculentus transcriptional and metabolic profiles, which can be used as reference for the development of strategies to increase oil content in C. esculentus tubers.

Oil body extraction from high-fat and high-protein soybeans by laccase cross-linked beet pectin: physicochemical and oxidation properties.

Soybean oil bodies (SOB) are droplets of natural emulsified oil. Soybean oil emulsifies well but it is easily oxidized during storage. Beet pectin is a complex anionic polysaccharide, which can be adsorbed on the surface of liposomes to improve their resistance to flocculation. Laccase can covalently cross-link ferulic acid in beet pectin, and its structure is irreversible, which can improve the stability of polysaccharides. At pH2.5, laccase cross-linked beet pectin high-oil soybean oil body (HOSOB) and high-protein soybean oil body (HPSOB) emulsions showed obvious aggregation and severe stratification, and the oxidation of the emulsions was also high. The flocculation of emulsions decreased with an increase in the pH. The effect of pH on the flocculation of emulsion was confirmed by confocal laser electron microscopy. The ζ potential, emulsification, and rheological shear force increased with increasing pH whereas the particle size and surface hydrophobicity decreased with increasing pH. This experiment indicates that the physicochemical stability of the two composite emulsions was strongly affected under acidic conditions but stable under neutral and weakly alkaline conditions. Under the same acid-base conditions, the degree of oxidation of HPSOB composite emulsion changes substantially. The results of this study can provide a basis for the design of very stable emulsions to meet the demand for natural products. © 2023 Society of Chemical Industry.

Identification of Key Lipogenesis Stages and Proteins Involved in Walnut Kernel Development.

Walnuts are abundant in oil content, especially for polyunsaturated fatty acids, but the understanding of their formation is limited. We collected walnut (Juglans regia L.) kernels at 60, 74, 88, 102, 116, 130, and 144 days after pollination (designated S1-S7). The ultrastructure and accumulation of oil bodies (OBs) were observed using transmission electron microscopy (TEM), and the oil content, fatty acid composition, and proteomic changes in walnut kernels were determined. The oil content and OB accumulation increased during the development and rose sharply from S1 to S3 stages, which are considered the key lipogenesis stage. A total of 5442 proteins were identified and determined as differentially expressed proteins (DEPs) using label-free proteomic analysis. Fatty acid desaturases (FAD) 2, FAD3, oleosin, and caleosin were essential and upregulated from the S1 to S3 stages. Furthermore, the highly expressed oleosin gene JrOLE14.7 from walnuts was cloned and overexpressed in transgenic Brassica napus. The overexpression of JrOLE14.7 increased the oil content, diameter, hundred weight of seeds and changed the fatty acid composition and OB size of Brassica napus seeds. These findings provide insights into the molecular mechanism of oil biosynthesis and the basis for the genetic improvement of walnuts.

Lipidomics reveals temporal changes in pecan kernel lipids during storage with or without sodium erythorbate treatment

Pecan nuts are rich in lipids that often degrade during storage; however, the progressive transformation of lipids in this process is still unclear. Therefore, high-throughput lipidomics was carried out based on ultrahigh-performance liquid chromatography coupled with a Q Exactive mass spectrometer (UPLC-Q Exactive MS). A total of 1451 lipid species from 5 classes and 24 subclasses were identified. Oxidized (Ox) phospholipids, fatty acid ester of hydroxy fatty acids, and N-oleoyl leucine were identified in pecan for the first time. The intensities of all diacylglycerols, phosphatidic acids (PAs), fatty acids, and fatty acid ester of hydroxy fatty acids increased obviously with pecan storage. Lipid hydrolysis was prevalent in both the control group and the treatment group during storage. Oxidation mainly did not occur on glycerolipids and glycerophospholipids in pecan. Lipids might be hydrolyzed first and released free fatty acids, which were then oxidized. Sodium erythorbate treatment could effectively delay the increase in peroxide value and the degradation of triacylglycerols. Differentially abundant lipids (DALs) were selected and could be used as markers for evaluating the deterioration of pecan during storage. Possible mechanisms of lipid degradation in pecan oil bodies during storage were also proposed.

Characterization of Oil Body and Starch Granule Dynamics in Developing Seeds of Brassica napus.

Brassica napus is the most important oilseed crop in the world, and the lipid was stored in the oil body (OB) in the form of triacylglycerol. At present, most of studies on the relationship between oil body morphology and seed oil content in B. napus was focused on mature seeds. In the present study, the OBs in different developing seeds of B. napus with relatively high oil content (HOC) of about 50% and low oil content (LOC) of about 39% were analyzed. It was revealed that the size of OBs was first increased and then decreased in both materials. And in late seed developmental stages, the average OB size of rapeseed with HOC was higher than that of LOC, while it was reversed in the early seed developmental stages. No significant difference was observed on starch granule (SG) size in HOC and LOC rapeseed. Further results indicated that the expression of genes that involved in malonyl-CoA metabolism, fatty acid carbon chain extension, lipid metabolism, and starch synthesis in the rapeseed with HOC was higher than that of rapeseed with LOC. These results give some new insight for understanding the dynamics of OBs and SGs in embryos of B. napus.

Effects of FeII, tannic acid, and pH on the physicochemical stability of oil body emulsions

This study examined the effects of solution pH (3.0, 5.0, and 7.0), FeII, and tannic acid (TA) on oil body (OB) emulsions and monitored changes in emulsion particle size, zeta potential, appearance, microstructure, and oxidation stability over 14 days of storage at 37 °C. The chelation efficiency, zeta potential, and fourier-transform infrared spectroscopy results showed that the ability of TA to chelate FeII and the absolute charge of TA-Fe complexes increased with the pH. In addition, the distribution of these complexes in the emulsions was influenced by their electrostatic and hydrogen bonding interactions with the OB. At pH 3.0 and 5.0, the TA-Fe and OB emulsion particles attracted each other, resulting in droplet flocculation. At pH 7.0, the TA-Fe and OB emulsion particles carried the same (negative) charge, and had little effect on physical stability of OB emulsions. TA generally inhibited the oxidation of OB emulsions but promoted the concentration of the primary and secondary oxidation products (61.48 mmol/kg and 50.5 μmol/kg, respectively) of FeII-containing emulsions at pH 3.0. The obtained results provide new insights into the efficacy of TA as a natural antioxidant for emulsified foods and thus pave the way to increasing their quality and shelf life.

The effect of sodium alginate on the nanomechanical properties and interaction between oil body droplets studied using atomic force microscopy

This study investigates the nanomechanical properties of different oil bodies (OBs), including soybean, peanut, sesame, and rapeseed, coated with sodium alginate (ALG), and the interaction between ALG-coated OBs using atomic force microscopy (AFM). Hooke's law, Reissner theory, and the Membrane model were respectively applied to analyze the nanomechanical properties of the linear and non-linear mechanics of the ALG-coated OBs. It was found that stiffness Kb and modulus ER from the linear deformation of ALG-coated OBs increased with the increase of the ALG layer thickness, while modulus Em from the non-linear deformation was larger than ER and correlated with the compression degree of the ALG layer. The interaction between pure OBs depended on the OB type. Electrostatic interaction which is related to the surface ζ-potential of the OBs occurs at a relatively long interaction distance, while at a relatively short distance, interfacial deformation of OBs occurs and the interaction force is affected by the structure and mechanics of OB interfacial membrane. After coating by ALGs, the electrostatic repulsion occurred from a longer distance than that between pure OBs, and both electrostatic repulsion and steric hindrance exist for a long interaction distance as the ALG-coated OBs continued to approach each other. ALG coating can also weaken the electrostatic screening effect of salt ions, avoiding aggregation of OBs and thus improving their stability. The present work demonstrates the feasibility of using AFM to study the mechanical properties and interaction of OB droplets at the molecular level, and reveals the mechanism of the influence of polysaccharide macromolecules on the stability of OB emulsions from the microscopic scale.

Study on oil body emulsion gels stabilized by composited polysaccharides through microgel particles compaction and natural gelation

Oil bodies (OBs), oil storage organelles of oilseeds, are natural, green, and sustainable products that have received much attention in recent years. Different ratios (4:0, 3:1, 2:2, 1:3, 0:4, w/w) of gelatinous polysaccharide κ-carrageenan (κ-Car) mixed with non-gelatinous polysaccharide xanthan (Xan) were used to stabilize OB emulsion gels by microgel particles (MPs) compaction or natural gelation with a total polysaccharide concentration of 0.5 wt%, respectively. Effects of two different treatments of polysaccharides on OB emulsion gels were compared by Fourier transform infrared spectroscopy (FTIR), rheology, and varied microscopy techniques, respectively. For natural gelation, the texture of OB emulsion gels was too rough to be employed in the food system. After compounding κ-Car with Xan, κ-Car and Xan were cross-linked to form a tighter network structure which improved the stability of OB emulsion gels by restricting the movement of OBs and water. Besides, the texture of OB emulsion gels became homogeneous. In addition, MPs compacted closely as micro-units to form a different type of network could benefit to homogeneous texture. The surface area of gels was expanded after microgel treatment, and the hydrogen bond strength enhanced. Unfortunately, the water seepage was more severe after microgel treatment. However, with the increase of Xan proportion before microgel treatment, the instability of OB emulsion gels stabilized by MPs could be improved significantly. This study allowed us to gain a better understanding of tailoring the texture of OB emulsion gels and broadening the application of OBs to low-fat food systems. • The stability of oil body emulsion gels can be advanced by mixing polysaccharides. • Microgel particles facilitated uniform texture of oil body emulsion gels. • Dense network structure was beneficial to the stability of oil body emulsion gels.

Transcriptomic comparison of seeds and silique walls from two rapeseed genotypes with contrasting seed oil content.

Silique walls play pivotal roles in contributing photoassimilates and nutrients to fuel seed growth. However, the interaction between seeds and silique walls impacting oil biosynthesis is not clear during silique development. Changes in sugar, fatty acid and gene expression during Brassica napus silique development of L192 with high oil content and A260 with low oil content were investigated to identify key factors affecting difference of their seed oil content. During the silique development, silique walls contained more hexose and less sucrose than seeds, and glucose and fructose contents in seeds and silique walls of L192 were higher than that of A260 at 15 DAF, and sucrose content in the silique walls of L192 were lower than that of A260 at three time points. Genes related to fatty acid biosynthesis were activated over time, and differences on fatty acid content between the two genotypes occurred after 25 DAF. Genes related to photosynthesis expressed more highly in silique walls than in contemporaneous seeds, and were inhibited over time. Gene set enrichment analysis suggested photosynthesis were activated in L192 at 25 and 35 DAF in silique walls and at both 15 and 35 DAF in the seed. Expressions of sugar transporter genes in L192 was higher than that in A260, especially at 35 DAF. Expressions of genes related to fatty acid biosynthesis, such as BCCP2s, bZIP67 and LEC1s were higher in L192 than in A260, especially at 35 DAF. Meanwhile, genes related to oil body proteins were expressed at much lower levels in L192 than in A260. According to the WGCNA results, hub modules, such as ME.turquoise relative to photosynthesis, ME.green relative to embryo development and ME.yellow relative to lipid biosynthesis, were identified and synergistically regulated seed development and oil accumulation. Our results are helpful for understanding the mechanism of oil accumulation of seeds in oilseed rape for seed oil content improvement.

Impact of interfacial layer number and Schiff base cross-linking on the microstructure, rheological properties and digestive lipolysis of plant-derived oil bodies-based oleogels

This study aims at development of plant-derived oil bodies (OBs) based oleogels via electrostatic layer-by-layer deposition technique that contained OB droplets coated by κ-carrageenan and chitosan, and then Schiff base cross-linked by vanillin. The effects of interfacial characteristics and Schiff bases on the formation and properties of OBs-based oleogels were investigated by analyzing microstructure, thermal stability, rheology, texture, protein degradation and lipid digestibility. Flowable to self-standing oleogels were obtained by alternating deposition of biopolymer coatings on OB droplets confirmed from macro-micro structure properties. The results from CLSM and cryo-SEM micrographs showed that OB droplets coated by the compact biopolymer layers were able to retain their structural integrity with uniform morphology and superior oil holding capacity (>99.7%), while vanillin addition fabricated micro-network structures that tightly packed the droplets. The creep-recovery rheology indicated that with an increase in vanillin concentration, oleogels changed from a viscoelastic bilayer interface to strong elastic oleogels due to Schiff bases formation. The resulting oleogels were thermally stable with high G′ (>3.5 × 104 Pa), yield stress (>1000 Pa), hardness (15.03 N), cohesiveness (0.60), and springiness (0.81) values, indicating that compact coating layers and vanillin-induced networks synergistically developed the solid oleogel structures. Furthermore, interfacial characteristics interfered with lipolysis as the FFA release rates of oleogels were considerably reduced with an increasing number of layers around OB droplets. Also, CLSM and SDS-PAGE results suggested that bilayer interface along with vanillin-induced interconnected structures exerted a strong protective effect during gastric process, being able to retain a part of undigested oleogels.

Extraction of structurally intact and well-stabilized rice bran oil bodies as natural pre-emulsified O/W emulsions and investigation of their rheological properties and components interaction

The isolated plant oil bodies (OBs) have shown promising applications as natural pre-emulsified O/W emulsions. Rice bran OBs can be used as a new type plant-based resource with superior fatty acids composition and abundant γ-oryzanol. This paper investigated the method of extracting structurally intact and stable rice bran OBs. Due to the adequate steric hindrance and electrostatic repulsion effects, rice bran OBs extracted by NaHCO3 medium had smaller particle size, better physical stability, and natural structure. The protein profile of NaHCO3-extracted rice bran OBs showed oleosin-L and oleosin-H, while exogenous proteins in PBS and enzyme-assisted- extracted rice bran OBs could interact with interfacial proteins through hydrophobic forces to aggregate adjacent OBs, further remodeling the OBs interface. It was also found that the small-sized rice bran OBs could adsorb on the interface of the larger-sized rice bran OBs like Pickering stabilizers. Rice bran OBs exhibited pseudoplastic fluids characteristic, but underwent a transition from solid-like to liquid-like behavior depending on the extraction method. The disorder of NaHCO3-extracted rice bran OBs protein molecules increased their surface hydrophobicity. The random coil structure favored more proteins adsorption at the interface of rice bran OBs extracted by PBS. Enzyme-assisted extraction of rice bran OBs had the highest content of β-sheet structure, which facilitated the stretching and aggregation of protein spatial structure. It was also confirmed the hydrogen bonding and hydrophobic interaction between the triacylglycerol or phospholipid and proteins molecules, and the membrane compositions of rice bran OBs differed between extraction methods.

Oil Bodies from Chia (Salvia hispanica L.) and Camelina (Camelina sativa L.) Seeds for Innovative Food Applications: Microstructure, Composition and Physical Stability

Exploring and deciphering the biodiversity of oil bodies (OBs) recovered from oilseeds are of growing interest in the preparation of sustainable, natural and healthy plant-based food products. This study focused on chia (Salvia hispanica L.) and camelina (Camelina sativa L.) seed OBs. A green refinery process including ultrasound to remove mucilage, aqueous extraction by grinding and centrifugation to recover OBs from the seeds was used. The microstructure, composition and physical stability of the OBs were examined. Confocal laser scanning microscopy images showed that chia and camelina seed OBs are spherical assemblies coated by a layer of phospholipids and proteins, which have been identified by gel electrophoresis. The mean diameters determined by laser light scattering measurements were 2.3 and 1.6 µm for chia and camelina seed OBs, respectively. The chia and camelina seed OBs were rich in lipids and other bioactive components with, respectively, 64% and 30% α-linolenic acid representing 70% and 53% of the total fatty acids in the sn-2 position of the triacylglycerols, 0.23% and 0.26% phospholipids, 3069 and 2674 mg/kg oil of β-sitosterol, and lipophilic antioxidants: 400 and 670 mg/kg oil of γ-tocopherol. Phenolic compounds were recovered from the aqueous extracts, such as rutin from camelina and caffeic acid from chia. Zeta-potential measurements showed changes from about -40 mV (pH 9) to values that were positive below the isoelectric points of pH 5.1 and 3.6 for chia and camelina seed OBs, respectively. Below pH 6.5, physical instability of the natural oil-in-water emulsions with aggregation and phase separation was found. This study will contribute to the development of innovative and sustainable food products based on natural oil-in-water emulsions containing chia and camelina seed OBs for their nutritional and health benefits.

A computational study on the structure–function relationships of plant caleosins

Plant cells store energy in oil bodies constructed by structural proteins such as oleosins and caleosins. Although oil bodies usually accumulate in the seed and pollen of plants, caleosins are present in various organs and organelles. This issue, coupled with the diverse activities of caleosins, complicates the description of these oleo-proteins. Therefore, the current article proposes a new classification based on the bioinformatics analysis of the transmembrane topology of caleosins. Accordingly, the non-membrane class are the most abundant and diverse caleosins, especially in lower plants. Comparing the results with other reports suggests a stress response capacity for these caleosins. However, other classes play a more specific role in germination and pollination. A phylogenetic study also revealed two main clades that were significantly different in terms of caleosin type, expression profile, molecular weight, and isoelectric point (P < 0.01). In addition to the biochemical significance of the findings, predicting the structure of caleosins is necessary for constructing oil bodies used in the food and pharmaceutical industries.

Oil body extraction from oleo-proteaginous seeds and conservation of valuable native compounds

Oil bodies, also called oleosomes have been the object of an increased interest since the last decade. Different processes of extraction and purification involve an aqueous crushing with methods to soften the cell membranes. An integrated process was used on different oilseeds to compare the different oil-body dispersions obtained. Once extracted with an aqueous crushing, oil bodies are dispersed in a creamy phase containing also an important protein content. Their stability depends on membranous proteins but also surrounding, extraneous ones. To eliminate these non-membranous proteins, the emulsion can be washed with different compounds allowing a good protein solubilization. If the fatty acid, phytosterol, tocopherol contents and distribution are compared between seeds and dispersions of oil bodies, there appears to be little significant change. These valuable compounds are hence preserved in the oil bodies. However, aqueous crushing releases phospholipase partly explaining the lower phospholipid content and the higher relative concentration of phosphatidic acid. To preserve these emulsions, it is possible to dry them either through freeze-drying or spray-drying. Spray-drying allows a better recovery of the physical structure of the emulsion after rehydration but cryo-protectants as Tris or Glycerol can limit emulsion degradation provoked by hard mechanical constraints of a freeze-drying process.

Dynamics of composition, structure, and metabolism of three energy substances in flaxseed (Linum usitatissimum L.) during germination

The composition and structure changes of three energy substances (protein, lipid, and sugar) and minerals during flaxseed germination were investigated. Na, Ca, Fe, and total free amino acids fluctuating increased and peaked at 7 d. Oil and ɑ-linolenic acid contents increased initially and reached the maximal increment by 14.8 % and 1.4 % (p < 0.05) at 2 d, after which it declined. Soluble sugar mainly consisted of sucrose (50.47 %–72.77 %), glucose, and fructose during germination. Semi-cylindrical depression was enhanced on flaxseed granule surface, and oil bodies distribution from relatively uniform toward cell wall during 0–2 d. Protein order and stability were varied firstly, then grew steadily at 4–7 d and peaked at 7 d. Metabolic sequence (sugar, protein, and lipid) and related tricarboxylic acid pathway were proposed. Conclusively, germinated flaxseed at 2 and 4 d had higher physicochemical and structural properties, which could serve as high-quality resources for lipid and protein processing respectively.

Formation, digestion properties, and physicochemical stability of the rice bran oil body carrier system

Rice bran is a major by-product of rice processing with abundant nutrient content. Oil bodies (OBs), which are fat particles with unique physicochemical stability, are specialized organelles for the storage of oils and fats in plant tissues. In this study, we extracted OBs from rice bran, to evaluate the function of hydrophobic nutrients efficiently delivered by OBs. The carrier system was prepared by sonicating curcumin with medium chain triglycerides (MCT) into rice bran oil bodies (RBOBs). Emulsions comprising different RBOB mass fractions were characterized. The results showed that the highest encapsulation efficiency (EE, 87.67%), optimal particle size (190 nm), and best storage stability were achieved with the 1.5 wt% RBOBs. Based on activity evaluation data, the carrier system can achieve sustained oil release in the intestine and shows high bioaccessibility (61.04%; IC50 in Caco-2 cells was 77.21 μg/mL), which is important for promoting grain by-product utilization.

Improve stability and application of rice oil bodies via surface modification with ferulic acid, (-)-epicatechin, and phytic acid

Rice bran oil bodies (RBOBs) are one of the most exploited functional components from rice bran by-products and are predominantly based on oleosin stabilization. In this study, we explored the effects of different concentrations of added (-)-epicatechin, ferulic acid, and phytic acid on the RBOBs stability. The results revealed that the incorporation of all three natural phytoconstituents could reduce the RBOBs particle size and increase emulsifying properties, demonstrating increasing surface hydrophobicity (p < 0.05), and a good antioxidant effect, which was especially obvious with (-)-epicatechin incorporation. Fourier transform infrared (FT-IR) spectroscopy data demonstrated that these three small molecule substance classes can modify with oleosin on RBOBs surface by covalent and noncovalent effects. Raman spectroscopic analysis illustrated that the vibrational modes of disulphide bonds in oleosin were modified by these three plant natural ingredients. The interactions between the three phytoconstituents and the model protein were investigated by molecular docking experiments.

Diterpenes of Coffea seeds show antifungal and anti-insect activities and are transferred from the endosperm to the seedling after germination

Species of the genus Coffea accumulate diterpenes of the ent-kaurane family in the endosperm of their seeds, of which cafestol and kahweol are the most abundant. The diterpenes are mainly stored in esterified form with fatty acids, mostly palmitate. In contrast to the numerous studies on their effects on human health and therapeutic applications, nothing was previously known about their biological and ecological role in planta. The antifungal and anti-insect activities of cafestol and cafestol palmitate were thus investigated in this study. Cafestol significantly affected the mycelial growth of five of the six phytopathogenic fungi tested. It also greatly reduced the percentage of pupation of larvae and the pupae and adult masses of one of the two fruit flies tested. By contrast, cafestol palmitate had no significant effect against any of the fungi and insects studied. Using confocal imaging and oil body isolation and analysis, we showed that diterpenes are localized in endosperm oil bodies, suggesting that esterification with fatty acids enables the accumulation of large amounts of diterpenes in a non-toxic form. Diterpene measurements in all organs of seedlings recovered from whole seed germination or embryos isolated from the endosperm showed that diterpenes are transferred from the endosperm to the cotyledons during seedling growth and then distributed to all organs, including the hypocotyl and the root. Collectively, our findings show that coffee diterpenes are broad-spectrum defence compounds that protect not only the seed on the mother plant and in the soil, but also the seedling after germination.

Silver nanoparticles modified hFGF2-linking camelina oil bodies accelerate infected wound healing

Bacterial infection wounds are common in life. At present, although various wound materials have shown antibacterial activity, there is a lack of overall strategy to promote wound healing. Therefore, it is necessary to develop multifunctional wound materials. In this study, silver nanoparticles (Ag NPs) modified camelina oil bodies (OB) which surface covalently bonded human fibroblast growth factor 2 (Ag NPs-hFGF2-OB) were designed for the treatment of bacterial infection wounds. The prepared Ag NPs-hFGF2-OB not only act as an antibacterial agent to realize sterilization, but also act as a tissue repair agent that effectively promotes wound healing. Ag+ was reduced in situ to Ag NPs by ascorbic acid, and the activity of hFGF2 protein was not affected after hFGF2-OB was modified by Ag NPs, which displaying broad apectrum antibacterial ability for both S. aureus and E. coli, with an antibacterial rate of more than 70 % (the concentration of Ag NPs was 20 μg/mL, the hFGF2 protein concentration was 20 µg/mL). Ag NPs-hFGF2-OB can effectively promote the migration of NIH/3T3 cells, showing good biocompatibility. The mouse bacterial infection wound model experiments proved that the wound healing rate of Ag NPs-hFGF2-OB group (the concentration of Ag NPs was 20 μg/mL, the hFGF2 protein concentration was 20 µg/mL) was much higher than other treatment groups, especially on the 7th day after treatment, the wound healing rate reached 71.71 ± 2.38 %, while the healing rate of other treatment groups were only 34.54 ± 1.10 %, 37.08 ± 2.85 % and 47.99 ± 2.01 %. Therefore, Ag NPs-hFGF2-OB, which can inhibit bacterial growth, promotes collagen deposition, granulation tissue regeneration and angiogenesis without any significant toxicity, shows good potential for application in the repair of bacterial infection wounds.

Interfacial characteristics of artificial oil body emulsions (O / W) prepared using extrinsic and intrinsic proteins: Inspired by natural oil body

In order to explore the stabilization mechanisms of intrinsic protein (IP) and extrinsic protein (EP) in natural oil-bodies, the effects of adding EP and IP in different relative proportions on the stability, interfacial characteristics, and digestibility of artificial oil body (AOB) emulsions were studied. The stability test results showed that the AOB emulsion prepared using 40% EP/60% IP exhibited the highest ζ-potential (−36.3 mV) and storage stability. According to the results of interface properties, competitive adsorption occurred at the interface in the emulsions prepared using IPs and EPs. Furthermore, by measuring the bioavailability of free fatty acids and curcumin during the digestion process, it was elucidated that 40% EP/60% IP developed a stable interfacial membrane, which facilitated the targeted release of curcumin in the intestine and yielded higher bioavailability. These results lay the foundation for clarifying the stabilization mechanism of natural oil body emulsions from an interfacial perspective.