Peanut Oil Body Composition and Stability

Investigating viscoelastic properties and structural stability mechanisms of oil bodies emulsion gels: Role of non-intrinsic protein

This research aims to investigate the mechanism of the effect of intrinsic and non-intrinsic protein content on the stability of oil bodies (OBs) emulsion gels. We employed small amplitude oscillation shear (SAOS) and large amplitude oscillation shear (LAOS) to measure the linear and nonlinear rheological properties of the OBs emulsion gels. The SAOS test indicated that an increase in non-intrinsic protein content weakened the interaction between OBs, decreasing their storage modulus (G'). The LAOS test demonstrated that the increase in non-intrinsic protein content affected the structural recombination and destruction behavior of OBs emulsion gels under large strains. Overall, the content of non-intrinsic protein during the extraction process is a crucial factor affecting the stability of OBs emulsion gels. These findings provide insights into the potential strategies for improving oil extraction efficiency and offer a foundation for further investigation into the functional properties of OBs.

Characteristic and stability changes of peanut oil body emulsion during the process of demulsification using heptanoic acid

In this paper, the changes in oil body emulsion (OBE) during heptanoic acid demulsification (HD) were investigated from the macro and microscopic points of view. Specifically, the OBE particle size increased from 3.04 to 8.41 µm, while the zeta potential absolute decreased to 2.89 mV. The interfacial tension and apparent viscosity of OBE were reduced significantly. Heptanoic acid could contribute to oil droplets aggregation. The findings indicated that high-molecular proteins, including lipoxygenase (97.58 kDa) and arachin (70.28 kDa), detached from the OBs' interface. HD caused alterations in the secondary structure of protein and the environment around proteins changed. The HD mechanism was speculated that the addition of heptanoic acid resulted in the reduction in pH and changes of environment surrounding OBE, which triggered polymerization and the phase transformation of the oil droplets. Overall, this study is vital for solving the problem of demulsification during aqueous enzymatic extraction (AEE).

Unveiling the applications of membrane proteins from oil bodies: leading the way in artificial oil body technology and other biotechnological advancements

Oil 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.

Flaxseed oleosomes: Responsiveness to physicochemical stresses, tribological shear and storage

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.

Effects of Pretreatment on Stability of Peanut Oil Bodies and Functional Characteristics of Proteins Extracted by Aqueous Enzymatic Method

Effects of dry and wet grind on peanut oil and protein yield, oil bodies (OBs) stability, fatty acid composition, protein composition and functional characteristics were systematically analyzed. Results showed that peanut oil and protein yields reached highest at dry grind 90 s (92.56% and 83.05%, respectively), while peanut oil and protein yields were 94.58% and 85.36%, respectively, at wet grind 120 s. Peanut oil and protein yields by wet grind was 2.18% and 2.78% higher than that of dry grind, respectively. Surface protein concentration (Г) and absolute value of zeta potential of OBs extracted by wet grind (WOBs) were 11.53 mg/m 2 and 18.51 mV, respectively, which were higher than OBs extracted by dry grind (DOBs), indicating stability of WOBs was higher than DOBs. Relative contents of oleic acid and linoleic acid in peanut oil, essential and hydrophobic amino acids in protein extracted by wet grind were higher than dry grind. There was little difference in protein composition between wet and dry grind, but thermal denaturation degree of protein obtained by wet grind was lower than dry grind. Solubility, oil retention, emulsion stability, foaming and foam stability of protein obtained by wet grind were better than dry grind. Results from this study provided theoretical basis for grind pretreatment selection of aqueous enzymatic method.

Effects of Roasting Temperatures on Peanut Oil and Protein Yield Extracted via Aqueous Enzymatic Extraction and Stability of the Oil Body Emulsion

Oil body emulsions (OBEs) affect the final oil yield as an intermediate in the concurrent peanut oil and protein extraction process using an aqueous enzyme extraction (AEE) method. Roasting temperature promotes peanut cell structure breakdown, affecting OBE composition and stability and improving peanut oil and protein extraction rates. Therefore, this study aimed to investigate the effects of pretreatment at different roasting temperatures on peanut oil and protein yield extracted through AEE. The results showed that peanut oil and protein extraction rates peaked at 90 °C, 92.21%, and 77.02%, respectively. The roasting temperature did not change OBE composition but affected its stability. The OBE average particle size increased significantly with increasing temperature, while at 90 °C, the zeta potential peaked, and the interfacial protein concentration hit its lowest, indicating OBE stability was the lowest. Optical microscopy and confocal laser scanning microscopy confirmed the average particle size findings. The oil quality obtained after roasting treatment at 90 °C did not differ significantly from that at 50 °C. The protein composition remained unaffected by the roasting temperature. Conclusively, the 90 °C roasting treatment effectively improved the yield of peanut oil extracted using AEE, providing a theoretical basis for choosing a suitable pretreatment roasting temperature.

Essential Components from Plant Source Oils: A Review on Extraction, Detection, Identification, and Quantification

Oils derived from plant sources, mainly fixed oils from seeds and essential oil from other parts of the plant, are gaining interest as they are the rich source of beneficial compounds that possess potential applications in different industries due to their preventive and therapeutic actions. The essential oils are used in food, medicine, cosmetics, and agriculture industries as they possess antimicrobial, anticarcinogenic, anti-inflammatory and immunomodulatory properties. Plant based oils contain polyphenols, phytochemicals, and bioactive compounds which show high antioxidant activity. The extractions of these oils are a crucial step in terms of the yield and quality attributes of plant oils. This review paper outlines the different modern extraction techniques used for the extraction of different seed oils, including microwave-assisted extraction (MAE), pressurized liquid extraction (PLE), cold-pressed extraction (CPE), ultrasound-assisted extraction (UAE), supercritical-fluid extraction (SFE), enzyme-assisted extraction (EAE), and pulsed electric field-assisted extraction (PEF). For the identification and quantification of essential and bioactive compounds present in seed oils, different modern techniques-such as high-performance liquid chromatography (HPLC), gas chromatography-mass spectrometry (GC-MS), Fourier transform infrared spectroscopy (FTIR), gas chromatography-infrared spectroscopy (GC-IR), atomic fluorescence spectroscopy (AFS), and electron microscopy (EM)-are highlighted in this review along with the beneficial effects of these essential components in different in vivo and in vitro studies and in different applications. The primary goal of this research article is to pique the attention of researchers towards the different sources, potential uses and applications of oils in different industries.

Demulsification of Emulsion Using Heptanoic Acid during Aqueous Enzymatic Extraction and the Characterization of Peanut Oil and Proteins Extracted

Peanut oil body emulsion occurs during the process of aqueous enzymatic extraction (AEE). The free oil is difficult to release and extract because its structure is stable and not easily destroyed. Demulsification can release free oil in an oil body emulsion, so various fatty acids were selected for the demulsification. Changes in the amount of heptanoic acid added, solid-liquid ratio, reaction temperature, and reaction time were adopted to investigate demulsification, and the technological conditions of demulsification were optimized. While the optimal conditions were the addition of 1.26% of heptanoic acid, solid-liquid ratio of 1:3.25, reaction temperature of 72.7 °C, and reaction time of 55 min, the maximum free oil yield was (95.84 ± 0.19)%. The analysis of the fatty acid composition and physicochemical characterization of peanut oils extracted using four methods were studied during the AEE process. Compared with the amount of oil extracted via other methods, the unsaturated fatty acids of oils extracted from demulsification with heptanoic acid contained 78.81%, which was significantly higher than the other three methods. The results of physicochemical characterization indicated that the oil obtained by demulsification with heptanoic acid had a higher quality. According to the analysis of the amino acid composition, the protein obtained using AEE was similar to that of commercial peanut protein powder (CPPP). However, the essential amino acid content of proteins extracted via AEE was significantly higher than that of CPPP. The capacity of water (oil) holding, emulsifying activity, and foaming properties of protein obtained via AEE were better than those for CPPP. Overall, heptanoic acid demulsification is a potential demulsification method, thus, this work provides a new idea for the industrial application of simultaneous separation of oil and proteins via AEE.

Impact of processing on the oxidative stability of oil bodies

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.

Molecular characterizations of genes in chloroplast genomes of the genus Arachis L. (Fabaceae) based on the codon usage divergence

Studies on the molecular characteristics of chloroplast genome are generally important for clarifying the evolutionary processes of plant species. The base composition, the effective number of codons, the relative synonymous codon usage, the codon bias index, and their correlation coefficients of a total of 41 genes in 21 chloroplast genomes of the genus Arachis were investigated to further perform the correspondence and clustering analyses, revealing significantly higher variations in genomes of wild species than those of the cultivated taxa. The codon usage patterns of all 41 genes in the genus Arachis were AT-rich, suggesting that the natural selection was the main factor affecting the evolutionary history of these genomes. Five genes (i.e., ndhC, petD, atpF, rpl14, and rps11) and five genes (i.e., atpE, psbD, psaB, ycf2, and rps12) showed higher and lower base usage divergences, respectively. This study provided novel insights into our understanding of the molecular evolution of chloroplast genomes in the genus Arachis.

Plant oil bodies and their membrane components: new natural materials for food applications

Plants store triacylglycerols in the form of oil bodies (OBs) as an energy source for germination and subsequent seedling growth. The interfacial biomaterials from these OBs are called OB membrane materials (OBMMs) and have several applications in foods, e.g., as emulsifiers. OBMMs are preferred, compared with their synthetic counterparts, in food applications as emulsifiers because they are natural, i.e., suitable for clean label, and may stabilize bioactive components during storage. This review focuses mainly on the extraction technologies for plant OBMMs, the functionality of these materials, and the interaction of OB membranes with other food components. Different sources of OBs are evaluated and the challenges during the extraction and use of these OBMMs for food applications are addressed.

Application of NIR spectroscopy for rapid quantification of acid and peroxide in crude peanut oil coupled multivariate analysis

Two key parameters (acidity and peroxide content) for evaluation of the oxidation level in crude peanut oil have been studied. The titrimetric analysis was carried out for reference data collection. Then, near-infrared spectroscopy in combination with chemometric algorithms such as partial least square (PLS); bootstrapping soft shrinkage-PLS (BOSS-PLS); uninformative variable elimination-PLS (UVE-PLS), and competitive-adaptive reweighted sampling-PLS (CARS-PLS) were attempted and assessed. The correlation coefficients of prediction (Rp), root mean square error of prediction (RMSEP) and residual predictive deviation (RPD) were used to individually evaluate the performance of the models. Optimum results were noticed with CARS-PLS, 0.9517 ≤ Rc ≤ 0.9670, 0.9503 ≤ Rp ≤ 0.9637, 0.0874 ≤ RMSEP ≤ 0.5650, and 3.14 ≤ RPD ≤ 3.64. Therefore, this affirmed that the near-infrared spectroscopy coupled with CARS-PLS could be used as a simple, fast, and non-invasive technique for quantifying acid value and peroxide value in crude peanut oil.

Influences of microwave exposure to flaxseed on the physicochemical stability of oil bodies: Implication of interface remodeling

This study aimed to investigate the influences of microwave (MV) exposure to flaxseed on the physicochemical stability of oil bodies (OBs) focused on the interface remodeling. The results showed that the intracellular OBs subjected to absolute rupture and then partial dispersion by protein bodies visualized by TEM following MV exposure (1-5 min; 700 W). After aqueous extraction, native flax OBs manifested excellent spherical particles with completely intact surface and wide particle size distribution (0.5-3.0 μm) examined by cryo-SEM. Upon 1-5 min of MV exposure, the defective interface integrity and beaded morphology were successively observed for flax OBs, accompanied by the impaired physical stability and rheological behavior due to the newly assembled phospholipid/protein interface. Notably, the profitable migration of phenolic compounds effectively suppressed the lipid peroxidation and protein carbonylation in flax OBs. Thus, MV exposure (1-5 min; 700 W) was unfavorable for improving the physical stability of flax OBs.

Digestibility and oxidative stability of plant lipid assemblies: An underexplored source of potentially bioactive surfactants?

Most lipids in our diet come under the form of triacylglycerols that are often redispersed and stabilized by surfactants in processed foods. In plant however, lipid assemblies constitute interesting sources of natural bioactive and functional ingredients. In most photosynthetic sources, polar lipids rich in ω3 fatty acids are concentrated. The objective of this review is to summarize all the knowledge about the physico-chemical composition, digestive behavior and oxidative stability of plant polar lipid assemblies to emphasize their potential as functional ingredients in human diet and their potentialities to substitute artificial surfactants/antioxidants. The specific composition of plant membrane assemblies is detailed, including plasma membranes, oil bodies, and chloroplast; emphasizing its concentration in phospholipids, galactolipids, peculiar proteins, and phenolic compounds. These molecular species are hydrolyzed by specific digestive enzymes in the human gastrointestinal tract and reduced the hydrolysis of triacylglycerols and their subsequent absorption. Galactolipids specifically can activate ileal break and intrinsically present an antioxidant (AO) activity and metal chelating activity. In addition, their natural association with phenolic compounds and their physical state (Lα state of digalactosyldiacylglycerols) in membrane assemblies can enhance their stability to oxidation. All these elements make plant membrane molecules and assemblies very promising components with a wide range of potential applications to vectorize ω3 polyunsaturated fatty acids, and equilibrate human diet.

Aqueous enzymatic extraction of peanut oil body and protein and evaluation of its physicochemical and functional properties

Aqueous enzymatic extraction (AEE) is a new technology for extracting vegetable oil body which has the advantages of low energy consumption, product safety, mild reaction conditions, and simultaneous separation of oil and protein. Among the enzymes tested in the present work, Viscozyme L (compound plant hydrolase) exhibited the highest extraction activity during peanut oil extraction. Extraction was optimized using response surface methodology, and optimal conditions were enzymatic temperature 51.5 °C, material-to-liquid ratio 1:3.5, enzymatic concentration 1.5%, and enzymatic time 90 min, yielding total oil body and protein of 93.67 ± 0.59% and 76.84 ± 0.68%, respectively. The fatty acid composition and content, and various quality indicators were not significantly different from those of cold-pressed oil, hence peanut oil produced by AEE met the same standards as cold-pressed first-grade peanut oil. Additionally, the functional properties of peanut protein produced by AEE were superior to those of commercially available peanut protein.

Effects of pH on the Composition and Physical Stability of Peanut Oil Bodies from Aqueous Enzymatic Extraction

Peanut oil body (POB), which is rich in unsaturated fatty acids and bioactive substances, is widely used in cosmetics, food, and medicine. Compared with synthetic emulsifiers, peanut oil bodies have health advantages as natural emulsions. The physicochemical properties of oil bodies affect their food processing applications. To improve peanut oil body yield, cell-wall-breaking enzymes were screened for aqueous enzymatic extraction. The optimum conditions were as follows: enzymatic hydrolysis time, 2 h; material-to-liquid ratio, 1 : 5 ( $m/v$ ); enzyme concentration, 2% ( $v/m$ ); and temperature, 50°C. Oil body stability was closely related to pH. With increasing pH, the average particle size and zeta-potential of the oil bodies increased, indicating aggregation, as confirmed by microstructure analysis. At pH 11, exogenous proteins at the oil body interface were eluted, leaving endogenous proteins, which led to a decreased interfacial protein content and oil body aggregation. Therefore, oil body stability decreased under alkaline pH conditions, but no demulsification occurred.

Composition and Rheological Properties of Peanut Oil Bodies from Aqueous Enzymatic Extraction

In this study, the relationship between the composition and rheological properties of peanut oil bodies from aqueous enzymatic extraction was evaluated. Aqueous enzymatic extraction using a combination of cellulase and pectinase at a 1:1 ratio effectively destroyed the structure of the cell wall and resulted in the maximum oil body yield of 90.7%. The microstructure and interfacial membrane composition of the peanut oil bodies were observed by confocal laser scanning microscopy. The oil bodies contained three inherent proteins (oleosin, caleosin, and steroleosin) along with two adsorbed foreign proteins (arachin and lipoxygenase). Five phospholipids were detected using ³¹P nuclear magnetic resonance spectroscopy. Among them, phosphatidylcholine, which plays a major role in the stability of oil bodies, was the most abundant. The measured rheological properties indicated that the oil bodies were a typical elastic system. Elevated temperature and high-speed shear destroyed the binding between proteins and phospholipids, reducing the oil body stability. The findings will facilitate the commercial application of peanut oil bodies by improving the extraction rate of peanut oil bodies and clarifying their stabilization mechanism.Practical Application: This paper studies the enzymatic extraction, composition and rheological properties of peanut oil bodies. It provides a theoretical basis for the large-scale application of peanut oil bodies in the food and cosmetic industries. It is beneficial to improve the application value of peanut resources.

Combination of Alcalase 2.4 L and CaCl2 for aqueous extraction of peanut oil

The combined application of CaCl₂ and Alcalase 2.4 L to the aqueous extraction process of peanuts was evaluated as a method to destabilize the oil body (OB) emulsion and improve the oil yield. After adding 5 mM CaCl₂ , the oil yield was reached to 92.0% which was similar with that obtained using Alcalase 2.4 L alone, and the required enzyme loading was decreased by approximately 60 times. In addition, the demulsification mechanism during aqueous extraction process was also investigated. Particle size and zeta-potential measurements indicated that the stability of the peanut OB emulsion dramatically decreased when CaCl₂ was added. Under these conditions, the demulsification of Alcalase 2.4 L performed was more efficiently. SDS-PAGE results showed that adding CaCl₂ changed the subunit structure of the peanut OB interface proteins and promoted the cross-linking among the arachin Ara h3 isoforms, resulting in unstable emulsions.