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[Display omitted] Cells store energy in lipid droplets, known as oleosomes, which have a neutral lipid core surrounded by a dilatable membrane of phospholipids and proteins. Oleosomes can be loaded with therapeutic lipophilic cargos through their permeable membrane and used as carriers. However, the cargo can also adsorb between the phospholipids and affect the membrane properties. In the present work, we investigated the effect of adsorbed curcumin on the mechanical properties of oleosome membranes using dilatational interfacial rheology (LAOD). The oleosome membrane had a weak-stretchable behavior, while the adsorption of curcumin led to stronger in-plane interactions, which were dependent on curcumin concentration and indicated a glassy-like structure. Our findings showed that adsorbed curcumin molecules can enhance the molecular interactions on the oleosome membrane. This behavior suggests that oleosomes membranes can be modulated by loaded cargo. Understanding cargo and membrane interactions can help to design oleosome-based formulations with tailored mechanical properties for applications. [ABSTRACT FROM AUTHOR]

The fruit surface is a critical first line of defense against environmental stress. Overlaying the fruit epidermis is the cuticle, comprising a matrix of cutin monomers and waxes that provides protection and mechanical support throughout development. The epidermal layer of the cucumber (Cucumis sativus L.) fruit also contains prominent lipid droplets, which have recently been recognized as dynamic organelles involved in lipid storage and metabolism, stress response, and the accumulation of specialized metabolites. Our objective was to genetically characterize natural variations for traits associated with the cuticle and lipid droplets in cucumber fruit. Phenotypic characterization and genome-wide association studies (GWAS) were performed using a resequenced cucumber core collection accounting for >96% of the allelic diversity present in the U.S. National Plant Germplasm System collection. The collection was grown in the field, and fruit were harvested at 16–20 days post-anthesis, an age when the cuticle thickness and the number and size of lipid droplets have stabilized. Fresh fruit tissue sections were prepared to measure cuticle thickness and lipid droplet size and number. The collection showed extensive variation for the measured traits. GWAS identified several QTLs corresponding with genes previously implicated in cuticle or lipid biosynthesis, including the transcription factor SHINE1/WIN1, as well as suggesting new candidate genes, including a potential lipid-transfer domain containing protein found in association with isolated lipid droplets. [ABSTRACT FROM AUTHOR]

Plant lipids are stored as emulsified lipid droplets also called lipid bodies, spherosomes, oleosomes or oil bodies. Oil bodies are found in many seeds such as cereals, legumes, or in microorganisms such as microalgae, bacteria or yeast. Oil Bodies are unique subcellular organelles with sizes ranging from 0.2 to 2.5 μm and are made of a triacylglycerols hydrophobic core that is surrounded by a unique monolayer membrane made of phospholipids and anchored proteins. Due to their unique properties, in particular their resistance to coalescence and aggregation, oil bodies have an interest in food formulations as they can constitute natural emulsified systems that does not need the addition of external emulsifier. This manuscript focuses on how extraction processes and other factors impact the oxidative stability of isolated oil bodies. The potential role of oil bodies in the oxidative stability of intact foods is also discussed. In particular, we discuss how constitutive components of oil bodies membranes are associated in a strong network that may have an antioxidant effect either by physical phenomenon or by chemical reactivities. Moreover, the importance of the selected process to extract oil bodies is discussed in terms of oxidative stability of the recovered oil bodies. [ABSTRACT FROM AUTHOR]

AbstractOil bodies (OBs) function as organelles that store lipids in plant seeds. An oil body (OB) is encased by a membrane composed of proteins (e.g., oleosins, caleosins, and steroleosins) and a phospholipid monolayer. The distinctive protein-phospholipid membrane architecture of OBs imparts exceptional stability even in extreme environments, thereby sparking increasing interest in their structure and properties. However, a comprehensive understanding of the structure-activity relationships determining the stability and properties of oil bodies requires a more profound exploration of the associated membrane proteins, an aspect that remains relatively unexplored. In this review, we aim to summarize and discuss the structural attributes, biological functions, and properties of OB membrane proteins. From a commercial perspective, an in-depth understanding of the structural and functional properties of OBs is important for the expansion of their applications by producing artificial oil bodies (AOB). Besides exploring their structural intricacies, we describe various methods that are used for purifying and isolating OB membrane proteins. These insights may provide a foundational framework for the practical utilization of OB membrane proteins in diverse applications within the realm of AOB technology, including biological and probiotic delivery, protein purification, enzyme immobilization, astringency detection, and antibody production. [ABSTRACT FROM AUTHOR]

[Display omitted] Oleosomes are natural oil droplets with a unique phospholipid/protein membrane, abundant in plant seeds, from which they can be extracted and used in emulsion-based materials, such as foods, cosmetics and pharmaceutics. The lubrication properties of such materials are essential, on one hand, due to the importance of the in-mouth creaminess for the consumed products or the importance of spreading the topical creams. Therefore, here, we will evaluate the lubrication properties of oleosomes, and how these properties are affected by the components at the oleosome membrane. Oleosomes were extracted, and their oral lubricating properties were evaluated using tribology. To understand the influence of the oil droplet membrane composition, reconstituted oleosomes were also studied, with membranes that differed in protein/lecithin ratio. Additionally, whey protein- and lecithin-stabilised emulsions were used as reference samples. Confocal laser scattering microscopy was used to study the samples visually before and after tribological analysis. Oleosomes followed a ball-bearing mechanism, which was probably related to their high physical stability due to the presence of membrane proteins. When the membrane protein concentration at the surface was reduced, the droplet stability weakened, leading to plating-out lubrication. Following our results, we elucidated the oleosome lubrication mechanism and showed their possible control by changing the membrane composition. [ABSTRACT FROM AUTHOR]

Safflower (Carthamus tinctorius) oleosomes are unique organelles that house triglycerides and fatty acids and demonstrate a natural resilience to environmental stresses. There is recent growing interest in safflower oleosomes due to their potential applications in dermatology, especially as a carrier technology to improve drug penetration through the skin. This paper explores various aspects of safflower oleosomes, including their production, safety, absorption, and applications in photoprotection and epidermal remodeling. Oleosomes have shown encouraging results in targeted drug delivery in in vitro and in vivo animal models; however, human clinical research is required to determine their efficacy and safety in dermatology. Oleosomes are comprise a novel biotechnology that has the potential to transform sustainable and natural treatments in dermatology by utilizing their unique structure. Safflower oleosomes are stable lipid molecules that can deliver small and large molecules with high efficacy. This review will examine the current research findings and prospective future applications of oleosomes. [ABSTRACT FROM AUTHOR]

In plants, the ability to produce hydrophobic substances that would provide protection from dehydration was required for the transition to land. This genome-wide investigation outlines the evolution of GDSL-type esterase/lipase (GELP) proteins in the moss Physcomitrium patens and suggests possible functions of some genes. GELP proteins play roles in the formation of hydrophobic polymers such as cutin and suberin that protect against dehydration and pathogen attack. GELP proteins are also implicated in processes such as pollen development and seed metabolism and germination. The P. patens GELP gene family comprises 48 genes and 14 pseudogenes. Phylogenetic analysis of all P. patens GELP sequences along with vascular plant GELP proteins with reported functions revealed that the P. patens genes clustered within previously identified A, B and C clades. A duplication model predicting the expansion of the GELP gene family within the P. patens lineage was constructed. Expression analysis combined with phylogenetic analysis suggested candidate genes for functions such as defence against pathogens, cutin metabolism, spore development and spore germination. The presence of relatively fewer GELP genes in P. patens may reduce the occurrence of functional redundancy that complicates the characterization of vascular plant GELP genes. Knockout lines of GELP31, which is highly expressed in sporophytes, were constructed. Gelp31 spores contained amorphous oil bodies and germinated late, suggesting (a) role(s) of GELP31 in lipid metabolism in spore development or germination. Future knockout studies of other candidate GELP genes will further elucidate the relationship between expansion of the family and the ability to withstand the harsh land environment. [ABSTRACT FROM AUTHOR]

Lipid droplets, also known as oil bodies or lipid bodies, are plant organelles that compartmentalize neutral lipids as a hydrophobic matrix covered by proteins embedded in a phospholipid monolayer. Some of these proteins have been known for decades, such as oleosins, caleosins, and steroleosins, whereas a host of others have been discovered more recently with various levels of abundance on lipid droplets, depending on the tissue and developmental stage. In addition to a growing inventory of lipid droplet proteins, the subcellular machinery that contributes to the biogenesis and degradation of lipid droplets is being identified and attention is turning to more mechanistic questions regarding lipid droplet dynamics. While lipid droplets are mostly regarded as storage deposits for carbon and energy in lipid-rich plant tissues such as seeds, these organelles are present in essentially all plant cells, where they display additional functions in signaling, membrane remodeling, and the compartmentalization of a variety of hydrophobic components. Remarkable metabolic engineering efforts have demonstrated the plasticity of vegetative tissues such as leaves to synthesize and package large amounts of storage lipids, which enable future applications in bioenergy and the engineering of high-value lipophilic compounds. Here, we review the growing body of knowledge about lipid droplets in plant cells, describe the evolutionary similarity and divergence in their associated subcellular machinery, and point to gaps that deserve future attention. [ABSTRACT FROM AUTHOR]

Understanding the diffusion process of hydrophobic molecules through natural phospholipid (half-)membranes is of great importance, as it occurs within organisms and therefore, offers potential applications in encapsulation in natural carriers. One illustrative case involves oleosomes, lipid droplets found in eukaryotic cells, which possess a phospholipid-protein monolayer facilitating the incorporation of lipophilic compounds into their inner core. Our approach entailed the development of a mathematical model to elucidate the diffusion of a lipophilic molecule, specifically curcumin, into oleosomes. In this model, oleosomes were represented as multilayer spheres with position-dependent diffusion and partition coefficients. We derived the model parameters through experimental techniques and stablished empirical equations. The model showed that 80% of curcumin reached the oil core while 20% stayed within the membrane (phospholipid heads and tails). Beyond its application to oleosomes and curcumin, the model presented herein holds broad application for describing the encapsulation of various lipophilic molecules into carriers featuring phospholipid (half-)membranes. [Display omitted] • A dynamic 1D model is used to study the mass transfer of curcumin in oleosomes. • The model is experimentally validated at equilibrium. • 80% of curcumin penetrated the oleosome core, while 20% at the interface. • The oil core contained the highest encapsulated mass. [ABSTRACT FROM AUTHOR]

Flaxseed oil bodies (FOBs) are being explored as natural plant-based delivery systems for the encapsulation and delivery of nutrients. However, there is currently a relatively poor understanding of their interfacial interaction and how this impacts delivery systems. In this study, β-carotene and lutein with far different molecular polarity were used to provide insights into their impacts on properties of FOB. In addition to the carotenoids (>93%) embedded and dissolved in the lipid core, they also interacted with the interfacial membrane components to impact the FOB properties. Raman showed the proportion of random coil and β-sheet in FOB-L (hydrophilic domain of interfacial protein) increased by 8% and 5% respectively, but remained almost unchanged in FOB-β, indicating lutein could interact with the polar exterior of interfacial membranes. Consistently, molecular dynamic simulations and spectroscopy analysis showed that lutein containing hydroxyl in β, ε-ionone ring was more likely to approach the outer hydrophilic regions of interfacial protein, while fatty soluble β-carotene interacted with hydrophobic region of inner membrane protein and phospholipid alkyl chain (close to oil). This difference in interfacial interactions induced significant discrepancies in the lipid oxidation, rheological behavior of carotenoid-FOB assemblies. Lutein was located at the outer edge where oxidation begins, making it more effective than β-carotene in improving the lipid oxidation stability of the FOB. Moreover, lutein therefore modulated interactions between oil droplets and altered the rheological properties of the FOB, whereas β-carotene had little effect. This study may facilitate the design of oil bodies-based delivery systems that have improved functional properties. [Display omitted] • Carotenoids encapsulated in natural Flaxseed oil body with mild sonication treatment. • Carotenoids with various molecular polarities had different location on OB interface. • β-carotene interacts with hydrophobic region of inner membrane (close to oil). • Lutein located at the outer edge can improve oxidation stability more effectively. • Lutein modulated OB-OB interactions and altered the rheological properties of the OB. [ABSTRACT FROM AUTHOR]

Liverworts are known for their large chemical diversity. Much of this diversity is synthesized and enclosed within oil bodies (OBs), a synapomorphy of the lineage. OBs contain the enzymes to biosynthesize and store large quantities of sesquiterpenoids and other compounds while limiting their cytotoxicity. Recent important biochemical and molecular discoveries related to OB formation, diversity, and biochemistry allow comparison with other secretory structures of land plants from an evo-devo perspective. This review addresses and discusses the most recent advances in OB origin, development, and function towards understanding the importance of these organelles in liverwort physiology and adaptation to changing environments. Our mapping of OB types and chemical compounds to the current liverwort phylogeny suggests that OBs were present in the most recent common ancestor of liverworts, supporting that OBs evolved as the first secretory structures in land plants. Yet, we require better sampling to define the macroevolutionary pattern governing the ancestral type of OB. We conclude that current efforts to find molecular mechanisms responsible for the morphological and chemical diversity of secretory structures will help understand the evolution of each major group of land plants, and open new avenues in biochemical research on bioactive compounds in bryophytes and vascular plants. [ABSTRACT FROM AUTHOR]

Oil bodies (OBs) are natural pre‐emulsion systems and an ideal green food additive. However, their proclivity to oxidation limits the applications of OBs. In this study, the effect of pasteurization (85 and 125 °C; 1 min) on membrane proteins and the oxidative stability of various OBs (soybean, sunflower, peanut, sesame, and walnut) were investigated. The membrane proteins are extracted from the OBs. The ultrahigh‐temperature pasteurization (125 °C, 1 min) eliminated lipoxygenase of soybean and peanut OBs. Furthermore, oleosin exhibited a higher denaturation temperature (approximately 100 °C) than extrinsic proteins (approximately 50 °C). Pasteurization induced the conversion of the α‐helix structure to a disordered structure by rearranging the hydrogen bonds. The pasteurized soybean and peanut OBs exhibited a high oxidative stability owing to their stable membrane structures and decreased lipoxygenase activity, while sunflower, sesame, and walnut OBs did not exhibit good oxidative stability because of their vulnerable membranes, a large number of unsaturated fatty acids, and severe aggregation of droplets. Simulated milk based on pasteurized soybean and peanut OBs (125 °C, 1 min) maintained outstanding storage stability. These results confirmed that pasteurized soybean and peanut OBs have the potential as a skim milk additive for the benefit of the consumer. [ABSTRACT FROM AUTHOR]

BACKGROUND: Soybean oil bodies (SOB) are naturally pre‐emulsified lipid droplets recovered directly from soybean seeds. Almost all food emulsions contain salts. However, it was not clear how the incorporation of salts affected the physicochemical stability of SOB. RESULTS: This study investigated the effect of NaCl (0–1.2%) on the physical and oxidative stability of SOB emulsions under neutral (pH 7) and acidic (pH 3) conditions. In the presence of NaCl, the SOB emulsion (pH 7) showed strong flocculation during storage due to electrostatic screening. The NaCl‐induced flocculation of SOB was attenuated at pH 3, which may be due to the difference in conformation or interaction of the protein interfaces covering SOB at different pH values. The increase in ionic strength or acid conditioning treatment resulted in a remarkable increase in the stability of SOB emulsions against coalescence. The confocal laser scanning microscopy images also confirmed the NaCl‐induced changes in the flocculation/coalescence properties of SOB. The oxidative behavior tests indicated that SOB emulsions containing NaCl were more susceptible to lipid oxidation but protein oxidation was inhibited due to electrostatic screening, which reduced pro‐oxidant accessibility of unadsorbed proteins in the emulsion. This oxidative behavior was attenuated at pH 3. CONCLUSION: The incorporation of NaCl significantly reduced the physical and oxidative stability of the SOB emulsion, and acidic pH mitigated NaCl‐induced flocculation and lipid oxidation of SOB. © 2021 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

Walnuts are renowned for their rich oil content and nutritional value, imparting significant health benefits. Walnut oleosomes, naturally present in a pre-emulsified state, can be effectively extracted through aqueous methods. Mechanical processes, such as twin-crew pressing or blending, are commonly employed to disrupt cell walls and extract oleosomes. Our study focused on investigating these two methods under varying soaking pH for walnut oleosomes extraction to develop an efficient extraction process for large-scale production or specific applications. Results showed that the oil content of extracted oleosomes ranged from 84.5% to 89.5%, with no substantial differences noted. Twin-screw pressing significantly achieved higher extraction yields (53.3–57.8%) compared to blending (35.7–36.4%), while blending produced walnut oleosomes with higher zeta potential, viscosity, storage modulus, and smaller particle size, improving physical stability compared to blended samples. The soaking pH levels minimally impacted extraction efficiency and physicochemical attributes of the oleosomes. Overall, blending offered oleosomes with relatively better physical stability, while twin-screw pressing was more advantageous for higher yields, making it more commercially viable for large-scale production. This study underscored the efficiency of sustainable approach in harnessing walnut oleosomes for various industrial applications. [Display omitted] • Type of mechanical treatments significantly impacted extraction yield of oleosomes. • Walnut oleosomes presented differing physical stability despite similar oil content. • Soaking pH of 7 or 9 had minimal effects on yield and stability of oleosomes. • The extraction pathways of oleosomes can be tailored based on target applications. [ABSTRACT FROM AUTHOR]

Cellulase is commonly used for the better release of phytonutrients due to its destructive coordinate effect on plant cell walls. In this study, cellulase hydrolysis showed a new feature: it significantly increased the physicochemical stability of flaxseed-based plant milk (FPM) due to interfacial modification of the oil bodies. Multispectroscopy and rheological measurement were performed to evaluate the stability of FPM, while the mechanical and oxidation stability of flaxseed oil bodies (FOBs) were characterized by rheological and induction period analysis, respectively. Additionally, Cryo-SEM, FTIR, and XRD analysis were used to provide structural information of FOBs' interface. Results revealed that cellulase treatment reduced the particle size and TSI of FPM, and significantly increased the adsorption of total polysaccharides at the FOBs' interface, with an increase of 20.25 ± 3.77% (P < 0.05). Furthermore, FOBs with enzyme treatment (EN-FOBs) possessed higher elastic modulus (G′) and viscous modulus (G″) at 90 °C than untreated ones. Meanwhile, the induction period of the EN-FOBs was prolonged by 10.47 ± 2.10% (P < 0.05). These findings indicated that cellulase promoted steady-state reconstruction of FPM by contributing to formation of complex interfaces with high mechanical strength. These results offer insight into innovation in plant-based milk processing technology towards green, clean labeling, and high-quality. [Display omitted] • Cellulase treatment enhanced the thermal stability and storage stability of FPM. • Cellulase promoted the adsorption of low-molecular-weight polysaccharide at FOBs. • Cellulase made FOBs with high G′ and G″ at 90 °C, representing strong mechanical strength. • Complex-adsorbed interfaces caused by cellulase treatment enhanced the stability of FOBs. [ABSTRACT FROM AUTHOR]

Oil bodies (OBs) are organelles for storing lipids, and they are composed of lipid cores and monolayer phospholipid protein membranes. During storage, membrane proteins anchored in the lipid core are often damaged by lipid oxidation products, leading to oxidative damage and a decreased quality of emulsified foods. Here, three natural antioxidants (gallic acid (GA), epigallocatechin gallate (EGCG), and tannic acid (TA)) were added to OB emulsions to study the effects of polyphenols on protein interfacial properties during oxidation and the lipid-protein co-oxidation behavior. Compared to GA, EGCG and TA with higher molecular weights and hydroxyl substitution showed better antioxidant activity, metal chelating activity, iron reduction ability, and affinity for OB. The polyphenols significantly reduced the contents of free amino and sulfhydryl groups in OB. Infrared spectroscopy analysis indicate that hydrogen bonding and hydrophobic interactions may exist between the polyphenols and OB. During storage, polyphenols inhibited >23% of the primary and secondary lipid oxidation products in the emulsions, whereas the formation of carbonyl groups and disappearance of sulfhydryl groups were only inhibited by 10.7% and 7.4%, respectively, indicating that polyphenols preferentially inhibited lipid oxidation over protein oxidation. Electrophoresis results showed that moderate oxidation (3 days of storage) disrupted the disulfide bonds of proteins. Note that moderate oxidation enhanced the interfacial properties of OB proteins, whereas excessive oxidation led to protein aggregation. This study offers new perspectives on using polyphenols to regulate the lipid-protein co-oxidation in OB, as well as the different properties of OB proteins after oxidation. [Display omitted] • Three polyphenols increase the stability of oil body (OB) emulsions. • Tannic acid with a high hydroxyl content has the best affinity for OB. • Hydrogen bonding and hydrophobic interactions occur between the polyphenols and OB. • Polyphenols are more likely to inhibit lipid oxidation than protein oxidation. • Moderate oxidation enhances the interfacial properties of proteins. [ABSTRACT FROM AUTHOR]

GDSL-type esterase/lipase protein (GELP) genes are crucial in the specialized lipid metabolism, in the responses to abiotic stresses, and in the regulation of plant homeostasis. R. communis is an important oilseed crop species that can sustain growth and productivity when exposed to harsh environmental conditions. Herein, we raised the question of whether the GELP gene family could be involved in the acquisition of R. communis tolerance to abiotic stresses during seed germination and seedling establishment. Thus, we used bioinformatics and transcriptomics to characterize the R. communis GELP gene family. R. communis genome possesses 96 GELP genes that were characterized by extensive bioinformatics, including phylogenetic analysis, subcellular localization, exon-intron distribution, the analysis of regulatory cis-elements, tandem duplication, and physicochemical properties. Transcriptomics indicated that numerous RcGELP genes are readily responsive to high-temperature and salt stresses and might be potential candidates for genome editing techniques to develop abiotic stress-tolerant crops. • R. communis GELP gene family was characterized by bioinformatics and transcriptomics. • R. communis genome possesses 96 GELP genes (GDSL-like Lipase/Acylhydrolase domain). • The majority of RcGELP genes are responsive to high-temperature and/or salt stress. • GELP genes are potential candidates to address stress-related agronomic crop issues. • Introduction. [ABSTRACT FROM AUTHOR]

Oleosomes are highly conserved organelles that store oil and can be utilized as a natural oil-in-water emulsion for food products when isolated intact. Although soybeans are a rich source of oleosomes, their potential has not been fully realized due to significant aggregation within the emulsion, which limits their applications. This study investigates the effect of homogenization as a strategy to prevent oleosome aggregation and coalescence. Our results indicate that homogenization at pressures of 10–30 MPa effectively prevents phase separation and preserves the initial particle size of oleosomes. However, at pressures of 40–50 MPa, oleosome particles are disrupted, leading to the formation of smaller particles that stabilize the emulsion against coalescence. We found that extracting oleosomes at a pH of 9 consistently produces stable emulsions, suggesting this method as a viable approach to enhance the stability of these emulsions. Furthermore, extraction at a pH of 7 followed by homogenization enhances the physical stability of the mixtures. Additionally, our findings demonstrate that performing extractions at pH 9 helps in preserving oleosome membrane-associated proteins, thereby further improving the stability and extending the storage potential of soybean oleosomes to up to 20 days. [Display omitted] • High-pressure homogenization can make stable soybean oleosome emulsions. • Oleosome extracted at pH 9 is more stable compared to the oleosome extracted at pH 7. • A homogenization pressure at 30 MPa or below can break the oleosome aggregates. • A homogenization pressure of 40 and 50 MPa leads to decrease the primary oleosome size. [ABSTRACT FROM AUTHOR]

[Display omitted] Hypothesis: Plant seeds store lipids in oleosomes, which are storage organelles with a triacylglycerol (TAG) core surrounded by a phospholipid monolayer and proteins. Due to their membrane components, oleosomes have an affinity for the air/oil–water interface. Therefore, it is expected that oleosomes can stabilise interfaces, and also compete with proteins for the air–water interface. Experiments: We mixed rapeseed oleosomes with whey protein isolate (WPI), and evaluated their air–water interfacial properties by interfacial rheology and microstructure imaging. To understand the contribution of the oleosome components to the interfacial properties, oleosome membrane components (phospholipids and membrane proteins) or rapeseed lecithin (phospholipids) were also mixed with WPI. Findings : Oleosomes were found to disrupt after adsorption, and formed TAG/phospholipid-rich regions with membrane fragments at the interface, forming a weak and mobile interfacial layer. Mixing oleosomes with WPI resulted in an interface with TAG/phospholipid-rich regions surrounded by whey protein clusters. Membrane components or lecithin mixed with proteins also resulted in an interface where WPI molecules aggregated into small WPI domains, surrounded by a continuous phase of membrane components or phospholipids. We also observed an increase in stiffness of the interfacial layer, due to the presence of oleosome membrane proteins at the interface. [ABSTRACT FROM AUTHOR]

Oil bodies (OBs), a special tissue that stores oil in plant cells, are rich in polyunsaturated fatty acid, vitamin E, phytosterols, and other functional components. In this study, different concentrations of xanthan gum (XG)-stabilized OBs were prepared using the electrostatic deposition technique, and oleogels were prepared via freeze-drying and shearing effects. The relationships between the properties of OB emulsions (OBEs), intermediate products (freeze-dried samples), and end products (oleogels) were explored. The XG addition significantly enhanced the stability of OBs. Particularly, when it achieved 1.5%, the average particle size of OBEs was the least at 892.03 nm, the ζ-potential absolute value was greater than 30 mV, and the porosity was a minimum of approximately 3.68%. Freeze-dried samples with XG had less oil on their surfaces, and their hardness and springiness were significantly and positively correlated with XG addition. The excellent stability of the OBEs and freeze-dried samples resulted in the formation of a dense and stable three-dimensional network structure to hold the oil. The oil holding capacity, rheological properties (including higher yield stress, stronger elastic, and thixotropy behavior), and thermal stability of the oleogels improved with increasing XG addition. Moreover, the compact networks and excellent oil holding capacity of the OB-based oleogels with XG effectively hindered high-temperature destruction and oil oxidation. The correlation analysis and the scheme model indicated that the oleogel properties could be traced back to the interaction effects among the OB components. These results provide guidance for the design and quality control of OB-based oleogels. [Display omitted] • Oleogels were formed using natural oil body (OB) emulsions as the template. • OB-based oleogels were successfully prepared by electrostatic deposition. • Xanthan gum increased the thermal and oxidative stability of OB-based oleogels. • The oleogel properties correlated with emulsions and freeze-dried samples. [ABSTRACT FROM AUTHOR]

Organisms have evolved intracellular micron-sized lipid droplets to carry and protect lipids and hydrophobic minor compounds in the hydrophilic environment of cells. These droplets can be utilized as carriers of hydrophobic therapeutics by taking advantage of their biological functions. Here, we focus on the potential of plant-derived lipid droplets, known as oleosomes, as carriers for hydrophobic therapeutics, such as curcumin. By spectroscopy and confocal microscopy, we demonstrate that the oleosome membrane is permeable to hydrophobic curcumin molecules. Fluorescence recovery after photobleaching shows rapid curcumin diffusion towards oleosomes, with a diffusion time in the range of seconds. Following this, quenching probes and dilatational rheology reveal that part of the loaded curcumin molecules can accumulate at the oleosome interface, and the rest settle in the inner core. Our findings shed light on the loading mechanism of the plant-derived lipid droplets and underscore the significance of molecular localization for understanding the mechanism. This work not only enhances the understanding of the loading process but also shows potential for oleosomes use as lipid carriers. [Display omitted] • Oleosome membrane is permeable for hydrophobic molecules • Curcumin was spontaneously diffused in oleosomes • Curcumin diffusion towards oleosomes was regulated by hydrophobic forces [ABSTRACT FROM AUTHOR]

Plants offer a vast variety of protein extracts, typically containing multiple species of proteins that can serve as building blocks of soft materials, like emulsions. However, the role of each protein species concerning the formation of emulsions and interfaces with diverse rheological properties is still unknown. Therefore, deciphering the role of the individual proteins in an extract is highly relevant, since it determines the optimal level of purification, and hence the sustainability aspects of the extract. Here, we will show that when oil/water emulsions were prepared with a rapeseed protein extract containing napins and cruciferins (in a mass ratio of 1:1), only napins adsorbed at the interface exhibiting a soft solid-like rheological behavior. The dominance of napins at the interface was ascribed to their small size (radius r = 1.7 nm) and its unique Janus-like structure, as 45% of the amino acids are hydrophobic and primarily located at one side of the protein. Cruciferins with a bigger size (r = 4.4 nm) and a more homogeneous distribution of the hydrophobic domains couldn't reach the interface, but they appear to just weakly interact with the adsorbed layer of napins. [ABSTRACT FROM AUTHOR]

Oil bodies (OBs) are lipid-storing organelles of plant seeds; they provide energy for seed germination and seedling growth by oxidative degradation as substrate. Soybean OBs are assumed to be involved in the enzymatic oxidation reaction of volatile flavor formation of soymilk. In order to establish a soymilk model system with soybean OBs as the enzymatic oxidation substrate to study the formation mechanism of soymilk flavor, the effects of extraction times and extraction pH on the composition, particle size and volatile flavor of soybean OBs extracted from raw soymilk were studied. The results showed that most of the extrinsic proteins on the surface of the OBs were removed with increasing extraction times. When the extraction pH increased from 7.0 to 11.0, the relative content of neutral lipids in OBs increased by 6.22%, and the relative content of protein and phospholipids in OBs decreased by 3.23% and 2.88%, respectively. The particle sizes of the OBs gradually decreased from 424 nm to 334 nm. The concentrations of volatile flavor components also gradually decreased from 129.29 μg/L to 52.75 μg/L. The integrity and stability of the OBs were compromised when the extraction pH was ≥12.0. The pH 11.0-OBs were the appropriate substrate for the soymilk model system because of their high purity and stability, better emulsion dispersion stability, and weaker flavor. These results are of great significance for exploring the formation mechanism of soymilk flavor in soymilk model systems to further improve the flavor of soymilk. [ABSTRACT FROM AUTHOR]

The spindle tree (Euonymus europaeus L.) is a much-branched deciduous shrub or small tree. Its fruit capsules contain seeds with remarkably high content of oil interesting for industry, especially the 3-acetyl-1,2-diacyl-sn-glycerols (AcDAG) synthesized by a specific acetyl-CoA diacylglycerol acetyltransferase. The distribution and amount of individual triacylglycerols (TAG) and especially acetyl-triacylglycerols (AcDAG) in Euonymus fruit have previously been assigned to specific tissues. Using anatomical and microscopical observations, we studied the fruit morphology, and for the first time, we identified a more detailed allocation of oil bodies in individual tissue structures. Thin layer chromatography separation of extracts from immature and mature fruits confirmed TAG and AcDAG as the most abundant lipid classes in both endosperm and embryo, followed by fatty acids and polar lipids. The abundance of fatty acids was further studied in the TAG and AcDAG fractions using gas chromatography. Data revealed particular FAs in both fractions allocated in tissue-specific manner and/or as indicators of maturation of E. europaeus seeds. While the abundance of cis-vaccenic-, linoleic as well as α-linolenic acids in the AcDAG structures generally drop with maturation in both embryo and endosperm, content of oleic acid increases. Abundance of cis-vaccenic acid in TAG was recorded in immature endosperm. For embryo, the abundance of stearic acid in AcDAG and oleic acid in TAG fraction was distinctive. Deeper understanding of underlying metabolic processes will be essential for targeted metabolic engineering and/or application for oilseed crops. [ABSTRACT FROM AUTHOR]

Induction of broad Th1 cellular immune responses and cytokines is crucial characteristics for vaccines against intracellular infections such as hepatitis C virus (HCV). Plants (especially oilseed tissues) and plant‐immunomodulators (like oil bodies) offer cost‐effective and scalable possibilities for the production of immunologically relevant and safe vaccine antigens and adjuvants, respectively. Herein, we provide data of the murine immunization by transgenic canola oilseed‐derived HCV core protein (HCVcp) soluble extract (TSE) and Escherichia coli‐ derived rHCVcp in combination with Canola oil bodies (oil) compared to that of the Freund's (FA) adjuvant. Mice immunized by TSE+ oil developed both strong humeral (IgG) and Th1‐biased cellular responses, manifested by high levels of IFN‐γ and lower IgG1/IgG2a ratio and IL‐4 secretion. Results of the intracellular cytokine staining indicated that TSE+ oil immunization in mice triggered both CD4+ and CD8+ T cells to release IFN‐γ, while CD4+ cells were mostly triggered when FA was used. Analyses by qRT‐PCR indicated that a combination of rHCVcp/TSE with oil body induced high levels of IL‐10 cytokines compared to that of the FA adjuvant. These characteristics are important properties for the design of an HCV vaccine candidate and indicate the potential of Canola‐derived antigen and oil bodies in addressing these concerns. [ABSTRACT FROM AUTHOR]

Natural oil bodies (OBs) from plant organs represent an important category of functional ingredients and materials in a variety of industrial sectors. Their applications are closely related to the membrane mechanical properties on a single droplet level, which remain difficult to determine. In this research, the mechanical properties of the membranes of OBs from soybean, sesame, and peanut were investigated in-situ by atomic force microscopy (AFM). Different regions of the force-deformation curves obtained during compression were analyzed to extract the stiffness K b or Young's modulus of the OB membranes using Hooke's law, Reissner theory, and the elastic membrane theory. At higher strains (ε = 0.15–0.20), the elastic membrane theory breaks down. We propose an extension of the theory that includes a contribution to the force from interfacial tension based on the Gibbs energy, allowing effective determination of Young's modulus and interfacial tension of the OB membranes in the water environment simultaneously. The mechanical properties of the OBs of different sizes and species, as well as a comparison with other phospholipid membrane materials, are discussed and related to their membrane compositions and structures. It was found that the natural OBs are soft droplets but do not rupture and can fully recover following compressive strains as large as 0.3. The OBs with higher protein/oil ratio, have smaller size and stronger mechanical properties, and thus are more stable. The low interfacial tension due to the existence of phospholipid-protein membrane also contributes to the stability of the OBs. This is the first report measuring the mechanical properties of OB membranes in - situ directly. [ABSTRACT FROM AUTHOR]

Oleosomes (or oil-bodies) are the oil storage structures of plant seeds. We typically extract oil by disrupting the oleosomes through mechanical-pressing of dry seeds and by using organic solvents. Nevertheless, it is possible to extract whole oleosomes, by breaking presoaked seeds. A key point to avoid oleosome damage seem s to be the soaking step. Hence the aim of this work was to understand the effect of soaking time on the mechanical properties of rapeseed and its effect on oleosome extraction. The results showed that the diffusion of water through the seeds was negatively associated to the mechanical strength of the seeds. This effect occurs in 3 stages and reaches a plateau at 8 h. The extraction of oleosomes and proteins kept constant for all different treatm ents. However, the duration of the soaking step influences oleosome integrity, as oleosomes extracted after shorter soaking times (<8 h) yielded bigger oleosomes with extraneous proteins bounded to them . After 8 h soaking time, the mechanical properties of the seeds kept constant and oleosomes of native size and with oleosome endogenous proteins were recovered. Therefore, a minimum soaking time of 8 h is required to achieve the extraction of intact oleosomes. [ABSTRACT FROM AUTHOR]

Physicochemical properties and emulsion stabilities of two types of oil bodies—crude oil bodies (COB) and purified oil bodies (OB)—recovered from high oleic peanuts via an aqueous enzymatic extraction process are investigated. RGB color analysis and flavor volatiles identification reveal that both COB and OB present desirable color and acceptable flavor. OB tends to have stronger antioxidant capacity and higher nutritional value compared to COB according to results from fatty acids, amino acids, and tocopherol analyses. The emulsification of oil bodies shows a slightly lower level than lecithin, but excellent thermal stability and storage stability (especially for OB), which relates greatly to small particle size, high zeta‐potential, and high content of hydrophobic amino acids. The freeze–thaw stability of OB is poorer than that of COB, which may relate to the presence of impurities in oil bodies. Thus, the peanut oil bodies, especially purified oil bodies, are proven to be advantageous emulsifying agents and additional valuable sources of antioxidants. Practical Applications: The results in this work clarify the differences in physiochemical composition and the fundamental emulsifying properties between COB and OB, and demonstrate the possibility of replacing traditional emulsifiers by natural green emulsifiers (e.g., oil bodies) in the food industry. Moreover, oil bodies extracted from high oleic peanuts, which contain plenty of unsaturated fatty acids and tocopherols, are a potential source for food supplements. In the long term, this work will increase the industrial conversion rate of oil bodies, enhance the processing and utilization level of high oleic peanuts, and promote the development of new foods based on peanut resources. [ABSTRACT FROM AUTHOR]

• Proteins exhibiting molecular weights of 3.5–152.8 kDa can stabilise 6 wt% oil. • Flaxseed oleosomes had a near zero zeta-potential at the pI (∼pH 3.0). • Electrostatics dominated stability with oleosomes aggregating in presence of Ca2+. • Oleosome droplets were stable for 6 weeks storage period. • Coalesced oleosomes in tribological contact resembled the profile of flaxseed oil. This study aimed to extract oleosomes (OLs) from flaxseeds and assess their response to environmental conditions during storage (pH and ionic strengths), shear and tribological stresses. Our hypothesis was that a shear-induced instability will enable OLs to exhibit favourable lubrication performance. During storage, OLs exhibited resistance to droplet aggregation for up to 6 weeks owing to the proteins (3.5–152.8 kDa molecular weights) stabilizing the OL droplets. However, presence of divalent (Ca2+) ions induced destabilization with marked increase in droplet size (p < 0.05). OLs demonstrated shear thinning behaviour, displaying an order of magnitude higher viscosity than flaxseed oil (FSO) at low shear rates (<10 s−1). Strikingly, OLs mirrored the frictional profile of FSO regardless of entrainment speeds, due to droplet coalescence, validating the hypothesis. Such kinetic stability with shear-induced coalescing feature of OLs hold strong potential for future plant-based food development, particularly in achieving desired mouthfeel characteristics. [ABSTRACT FROM AUTHOR]

Abstract The effect of the maize germ oil bodies in the form of a highly stable emulsion as a substitute for cow milk fat globules was investigated on the textural, physicochemical and sensory properties of a yoghurt-like product using a commercial yoghurt culture. The natural emulsion gave a satisfactory acidification kinetics pattern and an acid gel with a liquid-like structure. Gel formation was enhanced by skim milk incorporation, even more effectively when compared with cow milk with equal total solid content (16%, w/v), as determined by acidity, water holding capacity, syneresis, rheological and texture profile analysis. Studies on microbiological, physical and oxidative stability of the fortified yoghurt-like product reflect its quality assurance upon refrigerated storage. Different classes of endogenous bioactive constituents (mono- and polyunsaturated fatty acids, tocopherols) and volatile compounds derived from maize germ contribute to its high quality. Highlights • Maize germ (MG) oil bodies were incorporated in yogurt-like product. • Oil bodies from MG and milk protein network interaction improved gel formation. • High counts of starter culture ensured microbiological stability. • MG bioactive constituents and volatiles in the product improved its quality. [ABSTRACT FROM AUTHOR]

Highlights • Raw and roasted peanut milks were subject to HPH and thermal treatment. • High pressure homogenization reduce oil bodies size of both samples. • High pressure homogenization didn't enhance the stability of raw peanut milk. • Roasting improve the physical stability of peanut milk. • Protein profile of roasted peanut milk oil bodies has been changed. Abstract The effect of roasting, high-pressure homogenization HPH and thermal treatment on peanut milk and its oil bodies OBs was evaluated. Full-fat peanut milk samples were obtained using aqueous extraction method followed by HPH 150 or 300 MPs and pasteurization or sterilization. Roasting has a pronounced effect on the appearance, functional properties and the OBs protein membrane of peanut milk. The HPH significantly affected the microstructure, particle size, rheology and the color of raw and roasted peanut milk. Where, the size was significantly reduced, consistency index (k) decreased and the flow behavior index (n) increased with the increase in homogenization pressure. However, the raw peanut milk samples became more sensitive to sterilization. On the other hand, the roasted peanut milk samples subjected to homogenization were particularly stable to sterilization. Further, a combination of roasting, HPH and thermal treatment can provide a stable product with better flavor and without additives. [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Coconut oil bodies have polydisperse size distribution in the kernel cells. • The structure of coconut oil bodies is similar to those in oil seeds. • The oleosins stabilizing the coconut oil bodies are show disulfide bonding. Abstract This study investigated the structural characteristics of oil bodies from mature coconut (Cocos nucifera L.) fruit. The ultrastructure and the distribution of oil bodies in coconut endosperm were investigated using cryo-scanning electron microscopy. The interfacial characteristics of the oil bodies in suspensions isolated using two different protocols were studied using confocal laser scanning microscopy (CLSM), and the oleosins stabilizing the oil bodies were characterized using sodium dodecyl sulfate polyacrylamide electrophoresis. The oil bodies were found to be preferentially accumulated in endosperm tissues away from the inner endosperm and had a polydisperse size distribution, both intracellularly and in suspensions. The CLSM of oil bodies revealed uniform distribution of proteins and phospholipids at the interface along with glycolipids. Six different proteins were found to be associated with oil bodies some of which were disulfide-linked. This work provides new insights into the structure of coconut oil bodies and mechanisms for their stabilization. [ABSTRACT FROM AUTHOR]

Abstract Composite films based on sodium caseinate, plasticized with glycerol and incorporating oil bodies recovered by applying ultrafiltration on maize germ aqueous extract were stored at 25 °C and relevant humidity 53% and the changes in their physicochemical and mechanical properties were monitored over a storage period of 2 months. The rearrangement of the protein matrix molecules, oil droplet reorganization and movement during ageing was revealed through the generalized 2D correlation FTIR spectra analysis. Both the control and the oil bodies-containing caseinate films showed marked alterations of their mechanical and optical characteristics upon storage, mainly due to water uptake and glycerol or oil bodies movement, as the application of 2D correlation of the FTIR spectra time series revealed. The fact that the films become less transparent and, in addition, lose and then regain their mechanical strength during ageing for 70 days is essential information for the development of edible films and their commercial applications in the food industry. Graphical abstract Unlabelled Image Highlights • Composite sodium caseinate-oil bodies edible films were monitored during storage. • Sodium caseinates were found at the oil body surface along with endogenous proteins. • Control and composite films became opaquer through storage time. • Control tensile changes were due to water uptake and glycerol migration. • Oil bodies creaming was responsible for composite film tensile properties changes. [ABSTRACT FROM AUTHOR]

Oil seeds contain 10-20 wt% proteins and up to 50 wt% oil, organised in micron-sized oil droplets, named oleosomes. During oil extraction, which takes place using mechanical pressing or organic solvents or a combination of them, oleosomes are ruptured, and the oil is obtained. The oil extraction process might lead to the degradation of both the contained oil and proteins, therefore, as an effort to have a minimum impact on the quality of both, an aqueous extraction has been suggested, where oleosomes and proteins are simultaneously extracted. Oleosomes, being oil droplets themselves, can be used in emulsion-like food products, however, their extraction and purification from proteins is energy intensive. For a better understanding of the extraction and separation of oleosomes and proteins from sunflower seeds, we here explore the mass balance of oleosomes and proteins during each extraction step. Additionally, we investigate the effect of the process steps on oleosome physical stability. At the initial extract, oleosomes and proteins were at a 3:1 ratio, with an oleosome diameter of up to 10 μm. Three centrifugation steps were needed to separate proteins since the cream obtained had an oleosome/protein ratio close to 20:1. However, the removal of proteins had a significant effect on droplet coalescence, since oleosomes with a diameter up to 40–50 μm were observed. After a homogenisation step though, the oil droplets regained their initial size. Besides the effect on the physical stability of the sunflower oleosomes, the oleosome purification affected the obtaining yield, as from 87 wt% after the first extraction step, dropped to 66 wt%. By providing the mass balances during the oleosome/protein extraction from sunflower seeds, we highlight the effect of the sunflower oleosome purification steps on the obtaining yield and the role of the co-extracted storage proteins on their physical stability. Unlikely oleosomes from other sources, those derived from sunflower seeds, are prompt to coalescence when storage proteins are not present. With this insight, we provide tools for targeted sunflower oleosome and protein extraction depending on the potential applications and yield needed. [Display omitted] • The extraction of sunflower oleosomes can be tuned to obtain different oleosome/protein ratios. • Sunflower oleosomes can be purified at the cost of high water consumption. • Pure sunflower oleosomes are prompt to partial coalescence. • Coalesced sunflower oleosomes can return to their initial size through homogenisation. [ABSTRACT FROM AUTHOR]

[Display omitted] • Oil bodies (OBs) successfully loaded with curcumin (Cur) via ultrasonic and pH-driven. • Ultrasonic treatment was beneficial for the encapsulation and load of Cur. • Ultrasonic treatment improved the emulsion stability of Cur-loaded OBs. • Cur-loaded OB emulsions had the best stability and bioaccessibility at 200 W. In this study, oil bodies (OBs) loaded with curcumin (Cur) were successfully prepared via an ultrasonic and pH-driven method. Ultrasonic treatment significantly improved the encapsulation efficiency (EE) and loading capacity (LC) of Cur, producing OB particles with small size, uniform distribution, and high ζ-potential absolute values. When the ultrasonic power was 200 W, the EE, LC, and ζ-potential absolute value were the greatest (88.27 %, 0.044 %, and −25.71 mV, respectively), and the OBs possessed the highest yellowness, representing the best treatment result. The confocal laser scanning microscopy (CLSM) and cryo-scanning electron microscopy (cryo-SEM) results was also intuitionally shown that. Moreover, circular dichroism (CD) proved that ultrasonic treatment could unfold the surface protein structure, further enhancing the stability. Therefore, the cream index (CI), peroxide value (POV), and thiobarbituric acid reactive substances (TBARS) were the lowest when the ultrasonic power was 200 W. In this case, the Cur loaded in OBs was well protected against hostile conditions, evidenced by the highest Cur retention rate and the lowest degradation rate constant. Finally, the in vitro gastrointestinal digestion simulation results showed that the ultrasonic treatment effectively increased the release of FFA, bioaccessibility, and stability of Cur, especially when the ultrasonic power was 200 W. This research offers a new OB-based delivery system to stabilize, deliver, and protect Cur for food processing. [ABSTRACT FROM AUTHOR]

As a natural plant-derived oil-in-water emulsion, oil bodies (OBs) with fine membrane structure have a great potential to be a typical green entrapping system. The dense membrane of OBs protects the interior readily oxidizable substance, but also severely blocks the passage of biologically active substances. Given full considerations of both the mobility and rigidity of the OBs membrane, in this work, tepidity-ultrasonic (TU) method was firstly applied to incorporate β-carotene within flaxseed oil bodies (FOB). Laser Scanning Confocal Microscopy (LSCM), Atomic force microscopy (AFM) and Cryo-Scanning Electron Microscope (Cryo-SEM) measurements demonstrated that TU could induce the transformation of FOB membrane and greatly promoted β-carotene encapsulation into FOB interior. In consistent with rheology, the infrared, ultraviolet and fluorescence spectra of the membrane protein, as well as force-deformation curves confirmed that the inserted β-carotene weaken the interaction of components in the membrane to a sharp reduction in membrane stiffness. The subsequent ultrasonic triggered interfacial membrane remodeling and particle size reduction, causing a significant improvement of interfacial membrane stiffness nearly back its original state and ultimately improving the stability of the system. The optimal encapsulation rate of β-carotene (96.88%) could be obtained at optimized ultrasonic condition. After 30-day storage, the relative encapsulation efficiency of β-carotene in FOB-β-TU remained at 84.06%. Thus, this paper reveals that the synergistic effect of tepidity-stirring and ultrasonic provides the possibility for solvent-free assisted encapsulation of hydrophobic bioactive substances in natural OBs. This easily applicable method is also conducive to fulfill its application in multiple food processing. [Display omitted] • β-carotene incorporation and tepidity treatment changed the interaction between membrane protein and phospholipids • The translocation of interfacial protein may provide a pathway for β-carotene accessing. • Tepidity-ultrasonic successful promoted the entrapment of β-carotene into natural plant-derived FOB. • Interfacial membrane stiffness showed a significant tendency to return to the original state after ultrasound. • Ultrasound triggered interfacial membrane remodeling and ultimately improving the system stability. [ABSTRACT FROM AUTHOR]

[Display omitted] • Physical stability of flaxseed milk was slightly weakened upon microwave on flaxseed. • Microwave raised fluidity of flaxseed milk by stripped of gel structure in bulk phase. • Microwave favored embedding of storage protein-gum polysaccharide on oil body surface. • Microwave accelerated oil body collapse and lipolysis upon digestion of flaxseed milk. • Synergistic α-linolenic acid delivery was achieved for flaxseed milk upon microwave. The current study was to investigate how microwave on flaxseed affected the physicochemical stability and gastrointestinal digestion of oil bodies (OBs) in flaxseed milk. Flaxseed was subjected to moisture adjustment (30-35 wt%, 24 h), and microwave exposure (0–5 min, 700 W). Microwave treatment slightly weakened the physical stability of flaxseed milk indicated by Turbiscan Stability Index, but there were no visual phase separation during 21 days of storage at 4 °C. Upon microwave treatment, OBs experienced the layer-by-layer encapsulation into loose interface embedding by storage protein-gum polysaccharide complex from bulk phase, resulting in lower viscoelasticity of flaxseed milk. The OBs underwent earlier interface collapse and lipolysis during gastrointestinal digestion, followed by synergistic micellar absorption, faster chylomicrons transport within enterocytes of rats fed flaxseed milk. The accumulation of α-linolenic acid and synergistic conversion into docosapentaenoic and docosahexanoic acids in jejunum tissue were achieved accompanied by the interface remodeling of OBs in flaxseed milk. [ABSTRACT FROM AUTHOR]

Hypothesis Oleosomes are stabilized by a complex outer phospholipid-protein-layer. To improve understanding of its structure and stabilization mechanism, this shell has to be studied in extracellular native conditions. This should be possible by SANS using contrast variation. Oleosomes are expected to be highly temperature stable, with molecular changes occurring first in the protein shell. Direct measurements of changes in the shell structure are also important for processing methods, e.g. encapsulation. Experiments Extracted soybean oleosomes were studied directly and after encapsulation with pectin by SANS using contrast variation. In order to determine structure and size, a shell model of oleosomes was developed. The method was tested against a simple phospholipid-stabilized emulsion. The oleosomes’ temperature stability was investigated by performing SANS at elevated temperatures. Findings Size ( R g  = 1380 Å) and shell thickness of native and encapsulated oleosomes have been determined. This is the first report measuring the shell thickness of oleosomes directly. For native oleosomes, a shell of 9 nm thickness surrounds the oil core, corresponding to a layer of phospholipids and proteins. Up to 90 °C, no structural change was observed, confirming the oleosomes’ high temperature stability. Successful coavervation of oleosomes was shown by an increase in shell thickness of 10 nm after electrostatic deposition of pectin. [ABSTRACT FROM AUTHOR]

Peroxisomes are eukaryotic organelles critical for plant and human development because they house essential metabolic functions, such as fatty acid ß-oxidation. The interacting ATPases PEX1 and PEX6 contribute to peroxisome function by recycling PEX5, a cytosolic receptor needed to import proteins targeted to the peroxisomal matrix. Arabidopsis pex6 mutants exhibit low PEX5 levels and defects in peroxisomal matrix protein import, oil body utilization, peroxisomal metabolism, and seedling growth. These defects are hypothesized to stem from impaired PEX5 retrotranslocation leading to PEX5 polyubiquitination and consequent degradation of PEX5 via the proteasome or of the entire organelle via autophagy. We recovered a pex1 missense mutation in a screen for second-site suppressors that restore growth to the pex6-1 mutant. Surprisingly, this pex1-1 mutation ameliorated the metabolic and physiological defects of pex6-1 without restoring PEX5 levels. Similarly, preventing autophagy by introducing an atg7-null allele partially rescued pex6-1 physiological defects without restoring PEX5 levels. atg7 synergistically improved matrix protein import in pex1-1 pex6-1, implying that pex1-1 improves peroxisome function in pex6-1 without impeding autophagy of peroxisomes (i.e., pexophagy). pex1-1 differentially improved peroxisome function in various pex6 alleles but worsened the physiological and molecular defects of a pex26 mutant, which is defective in the tether anchoring the PEX1-PEX6 hexamer to the peroxisome. Our results support the hypothesis that, beyond PEX5 recycling, PEX1 and PEX6 have additional functions in peroxisome homeostasis and perhaps in oil body utilization. [ABSTRACT FROM AUTHOR]

An aqueous process for the recovery of oil bodies from rapeseed using sodium bicarbonate-based soaking and grinding media (pH 9.5) was investigated. The effect of the ratio between seed and mass of media during grinding and molarity of the medium used on oil body integrity, purity and storage stability have been studied. The grinding of seeds in solution at a ratio of 1:7 (w/w) significantly improved the quality of oil body suspension to a size more in-line with that seen in vivo (average D 4,3 of 1.19 µm). The purity and the composition of the recovered oil bodies depends on the molarity of medium used; the use of a sodium bicarbonate solution (pH 9.5, 0.1 M) in the grinding and washing steps produced oil body preparations with the same purity as that resulting from washing a crude preparation with 9 M urea. The resultant emulsion had improved physical stability over a storage period of one month. [ABSTRACT FROM AUTHOR]

Oleosomes are natural oil droplets, present in all organisms and abundant in oilseeds. After their aqueous extraction from oilseeds, they can be directly utilized as oil droplets in food, cosmetics and all types of oil-in-water emulsion systems. However, to expand the potential uses of oleosomes as green ingredients and to valorize oilseeds as efficient as possible, we explored their emulsifying ability. Oleosomes were extracted from rapeseeds, and 10.0 wt% oil-in-water emulsions were created after homogenization with 0.5–6.0 wt% oleosomes, and the droplet size of the emulsions and their structure was measured by laser diffraction and confocal laser scanning microscopy (CLSM), respectively. The emulsion with an oleosome concentration lower than 1.0 wt% gave unstable emulsions with visible free oil. At oleosome concentrations at 1.5 wt% or higher, we obtained stable emulsions with droplet sizes between 2.0 and 12.0 µm. To investigate the role of the oleosome interfacial molecules in stabilizing emulsions we also studied their emulsifying and interfacial properties (using drop tensiometry) after isolating them from the oleosome structure. Both oleosomes and their isolated interfacial molecules exhibited a similar behavior on the oil-water interfaces, forming predominantly elastic interfacial films, and also showed a similar emulsifying ability. Our results show that oleosomes are not stabilizing the oil-in-water emulsions as intact particles, but they provide their interfacial molecules, which are enough to stabilize an oil-water surface up to about 2 times bigger than the initial oleosome surface. The understanding of the behavior of oleosomes as emulsifiers, opens many possibilities to use oleosomes as alternative to synthetic emulsifiers in food and pharma applications. [Display omitted] • Rapeseed oleosomes are natural droplets with a phospholipid-protein membrane. • An oleosome conc. of 1.5 wt% is enough to provide stable 10 wt% O/W emulsions. • The oleosome interfacial molecules stabilize the newly formed emulsion droplets. • Oleosomes have a potential as natural emulsifiers. [ABSTRACT FROM AUTHOR]

The seeds of many legume species including soybean, Pongamia pinnata and the model legume Medicago truncatula store considerable oil, apart from protein, in their cotyledons. However, as a group, legume storage strategies are quite variable and provide opportunities for better understanding of carbon partitioning into different storage products. Legumes with their ability to fix nitrogen can also increase the sustainability of agricultural systems. This review integrates the cell biology, biochemistry and molecular biology of oil body biogenesis before considering biotechnology strategies to enhance oil body biosynthesis. Cellular aspects of packaging triacylglycerol (TAG) into oil bodies are emphasized. Enhancing seed oil content has successfully focused on the up-regulation of the TAG biosynthesis pathways using overexpression of enzymes such as diacylglycerol acyltransferase1 and transcription factors such as WRINKLE1 and LEAFY COTYLEDON1. While these strategies are central, decreasing carbon flow into other storage products and maximizing the packaging of oil bodies into the cytoplasm are other strategies that need further examination. Overall there is much potential for integrating carbon partitioning, up-regulation of fatty acid and TAG synthesis and oil body packaging, for enhancing oil levels. In addition to the potential for integrated strategies to improving oil yields, the capacity to modify fatty acid composition and use of oil bodies as platforms for the production of recombinant proteins in seed of transgenic legumes provide other opportunities for legume biotechnology. [ABSTRACT FROM AUTHOR]

Catabolism of fatty acids stored in oil bodies is essential for seed germination and seedling development in Arabidopsis. This fatty acid breakdown occurs in peroxisomes, organelles that sequester oxidative reactions. Import of peroxisomal enzymes is facilitated by peroxins including PEX5, a receptor that delivers cargo proteins from the cytosol to the peroxisomal matrix. After cargo delivery, a complex of the PEX1 and PEX6 ATPases and the PEX26 tail-anchored membrane protein removes ubiquitinated PEX5 from the peroxisomal membrane. We identified Arabidopsis pex6 and pex26 mutants by screening for inefficient seedling β-oxidation phenotypes. The mutants displayed distinct defects in growth, response to a peroxisomally metabolized auxin precursor, and peroxisomal protein import. The low PEX5 levels in these mutants were increased by treatment with a proteasome inhibitor or by combining pex26 with peroxisome-associated ubiquitination machinery mutants, suggesting that ubiquitinated PEX5 is degraded by the proteasome when the function of PEX6 or PEX26 is reduced. Combining pex26 with mutations that increase PEX5 levels either worsened or improved pex26 physiological and molecular defects, depending on the introduced lesion. Moreover, elevating PEX5 levels via a 35S: PEX5 transgene exacerbated pex26 defects and ameliorated the defects of only a subset of pex6 alleles, implying that decreased PEX5 is not the sole molecular deficiency in these mutants. We found peroxisomes clustered around persisting oil bodies in pex6 and pex26 seedlings, suggesting a role for peroxisomal retrotranslocation machinery in oil body utilization. The disparate phenotypes of these pex alleles may reflect unanticipated functions of the peroxisomal ATPase complex. [ABSTRACT FROM AUTHOR]

Vegetable 'milk' obtained by aqueous extraction of oil bodies from maize germ, hazelnut, or sesame seed, followed by concentration of the extracts by ultrafiltration were subjected to thermal treatment to ensure their microbial quality and safety. Thermal treatment did not induce any important variations on the volatile profile of the hazelnut and sesame seed 'milk' products, while the aroma character of maize germ 'milk' was appreciably affected. The physical stability of both the maize germ and hazelnut 'milk' was not adversely influenced by the thermal treatment as they exhibited satisfactory stability against droplet aggregation/coalescence during storage. On the contrary, the heated sesame seed 'milk' was destabilized through the development of droplet aggregates. Studies on the oxidative stability of the 'milk' products revealed a positive effect of heating while no losses in different classes of endogenous bioactive constituents (tocopherols and lignans) were observed. The potential industrial applications are discussed. Practical applications: The consumption of food products with enhanced health benefits such as vegetable 'milk' is gaining ground due to the change of the dietary habits of the consumers towards non-dairy products. The stability of 'milk' products based on concentrated (i.e., by ultrafiltration) aqueous oil body extracts of maize germ, hazelnut, and sesame seed has never been examined before. The investigation of the impact of thermal treatment on the microbiological, physical, and oxidative stability of such product is of scientific interest as well as of practical application since it reflects the quality assurance and the higher economic sustainability of such products in the market. The hazelnut and maize germ 'milks' are promising novel products while sesame seed 'milk' can be used as raw material for other applications. [ABSTRACT FROM AUTHOR]

Background: Lobosphaera incisa (L. incisa) is an oleaginous microalga that stores triacylglycerol (TAG) rich in arachidonic acid in lipid bodies (LBs). This organelle is gaining attention in algal research, since evidence is accumulating that proteins attached to its surface fulfill important functions in TAG storage and metabolism. Results: Here, the composition of the LB proteome in L incisa was investigated by comparing different cell fractions in a semiquantitative proteomics approach. After applying stringent filters to the proteomics data in order to remove contaminating proteins from the list of possible LB proteins (LBPs), heterologous expression of candidate proteins in tobacco pollen tubes, allowed us to confirm 3 true LBPs: A member of the algal Major Lipid Droplet Protein family, a small protein of unknown function and a putative lipase. In addition, a TAG lipase that belongs to the SUGAR DEPENDENT 1 family of TAG lipases known from oilseed plants was identified. Its activity was verified by functional complementation of an Arabidopsis thaliana mutant lacking the major seed TAG lipases. Conclusions: Here we describe 3 LBPs as well as a TAG lipase from the oleaginous microalga L. incisa and discuss their possible involvement in LB metabolism. This study highlights the importance of filtering LB proteome datasets and verifying the subcellular localization one by one, so that contaminating proteins can be recognized as such. Our dataset can serve as a valuable resource in the identification of additional LBPs, shedding more light on the intriguing roles of LBs in microalgae. [ABSTRACT FROM AUTHOR]

Soybeans contain oil bodies (OBs) that encapsulate triacylglycerols (TAGs) with a phospholipid monolayer carrying scattered proteins. In nature, soybean OBs can form natural emulsions in aqueous media and may serve as natural, minimally processed, stable, and pre-emulsified oil for addition into appropriate food systems. In this study, OBs were obtained by aqueous extraction from the mature seeds of 2 soybean crop cultivars, high-fat soybean and low-fat soybeans. The compositions of the extracted OBs were analyzed during storage at room temperature up to 14 d (pH = 7). The oxidative stability of these OBs, stored at 60 °C, was evaluated by measuring the presence of primary (lipid hydroperoxides) and secondary lipid oxidation products (malondialdehyde) by determining the standard peroxide value (PV) and thiobarbituric acid-reactive substances (TBARS) value. During storage, the contents of unsaturated fatty acids, phospholipids, and tocopherols declined in both OBs, while their mean particle diameters ( d32) and ζ-potentials increased. The changes in PV and TBARS values exhibited a similar trend for both OBs, but the OBs from low-fat soybeans had significantly lower PV and higher TBARS values than the OBs from high-fat soybean cultivars ( P < 0.05). Overall, the OBs from both soybean cultivars had good stability during storage. [ABSTRACT FROM AUTHOR]

Structures present in Nature have evolved over millions of years to achieve optimized functionalities. In the recent past, characterization techniques have been developed progressively allowing to better access and understand complex bio-architectures and structure–function relationships. Since in Nature energy is limited, weak interactions play a fundamental role for building supramolecular hierarchical structures. Self-assembly formation is a crucial process for building those complex architectures. In this article we will describe what types of structures are formed in Nature using the self-assembly concepts, and how those can be utilized to generate new benefits in food products. Our description will concentrate on examples where both self-assembled structure formation and functionality in food products are conceived and enhanced on inspiration by Nature. Our major interest here concerns the following architectures: 1) cell membranes formed mainly by phospholipids, 2) the phospholipid/protein membrane of oil bodies and 3) self-assemblies formed during lipid digestion. We will then explain how these self-assemblies are used both in Nature and food material science to obtain compartmentalization and structures for improved product performance regarding controlled release of aromas and nutrients, bioavailability, Maillard-type chemical reactions and chemical and physical stability. Such self-assemblies are present in many food products but could be much better used to create new benefits for the consumer. [ABSTRACT FROM AUTHOR]

• Oil bodies from rice bran were used as carriers for curcumin. • Carrier systems were prepared by sonicating curcumin into rice bran oil bodies. • The small particle size and the good stability of carrier systems were obtained. • The digestion behavior and uptake were analysed by in vitro activity evaluation. 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%; IC 50 in Caco-2 cells was 77.21 μg/mL), which is important for promoting grain by-product utilization. [ABSTRACT FROM AUTHOR]

Oleosins are unique proteins that are crucial for the stabilization of the oil droplets, that nature designed to store and protect triacylgycerols in seeds. To better understand and possibly replicate the role of oleosins in the stability of oil droplets, an efficient extraction for oleosins is necessary, which has not been achieved yet. Oleosins consist of a long central hydrophobic hairpin that is attached to two hydrophilic arms. This high amphiphilicity makes their extraction a challenging task. The aim of the present work was to develop a scalable method to extract oleosins from rapeseed oleosomes using washing steps with methanol, hexane, and ethanol (MHE). Following this method, we obtained oleosins with a recovery of 94 ± 1.4 wt% and a purity of 87.1 ± 1.9 wt%. The recovery was significantly higher (p < 0.005) compared to the commonly applied Folch extraction (recovery of 57.2 ± 5.5 wt%). Oleosins formed micro- and nanosized aggregates when dispersed in aqueous solutions, because of their long hydrophobic moiety. The fraction of nanosized aggregates was 6-fold higher for the oleosins obtained with the MHE method in comparison to those obtained using the Folch method. Due to the smaller aggregates, oleosins obtained using the MHE method were more efficient in reducing the oil-water interfacial pressure and formed a stronger interfacial film in comparison to those obtained with the Folch method. The highly efficient and scalable oleosin extraction, paves the way for elucidating the stabilizing role of oleosins and the way towards industrial oleosin extraction. [Display omitted] • A new scalable method to extract oleosins was developed. • This method recovers ∼95% of oleosins from oleosomes with a purity of 87%. • Oleosins formed micro- and nanosized aggregates in aqueous solutions. • Oleosins form solid-like layer at oil-water interface. [ABSTRACT FROM AUTHOR]