Soybean Oil Bodies Research Articles

Enhancing the physicochemical stability and bioaccessibility of curcumin-loaded soybean oil bodies emulsions in the in vitro elderly model

Curcumin, a hydrophobic polyphenol, provides numerous health benefits, but its limited water solubility, stability and bioavailability hinder its applications in the food and pharmaceutical products, while its biological fate in elderly is unclear. In this study, a natural soybean oil bodies-curcumin (SOB-C) emulsion was fabricated using a pH-driven method without the use of organic solvents to minimize environmental impact. The digestive properties, curcumin bioaccessibility, free fatty acids (FFA), and microstructural changes of SOB-C were investigated using an in vitro elderly digestion model. The findings indicated that curcumin was successfully encapsulated within SOB with an efficiency of up to 90%. Compared to free curcumin, the curcumin encapsulated within SOB demonstrated a significant enhancement in the light, storage stability, and an extension of the curcumin's half-life up to 74 days. The in vitro elderly digestion findings demonstrated that SOB-C significantly improved the bioaccessibility of curcumin, increasing it from 14.30% to 38.98%, surpassing the efficacy of the two commercial curcumin. The reduced FFA release rate from SOB-C supports its potential utility in low-fat food formulations. The results indicated the SOB play a significant role in encapsulating and stabilizing hydrophobic bioactives, which are promising curcumin delivery system to be used in food products for the elderly.

Physicochemical and rheological properties of soybean oil body fermented milk: Impacts of high pressure homogenization

In the present research, the impacts of high-pressure homogenization (HPH) (20, 60, 90, 120 and 150 MPa) on the physicochemical, rheological and sensory properties of soybean oil body (SOB) fermented milks were explored. Experimental results showed that with the increase of HPH pressure, acidity and water-holding capacity (WHC) of SOB fermented milk significantly increased, while its pH, peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) significantly decreased. The SOB fermented milk was found to be pseudoplastic fluids and the SOB fermented milk at 150 MPa had the highest apparent viscosity. Meanwhile, the SOB fermented milk of 150 MPa possessed the highest sensory score. Finally, principal component analysis (PCA) and heatmap showed that SOB fermented milk had the best characteristics after HPH treatment at 150 MPa. Therefore, HPH pressure could observably improve sensory, textural and rheological properties of SOB fermented milk. These results provide theoretical reference for HPH treatment to develop high-quality fermented dairy products.

Effects of electrochemical treatment and Epigallocatechin-3-gallate on emulsification, rheological and oxidation stability of soybean oil body

In this study, the soybean oil body (SOB) was placed in the cathode chamber of an electrochemical reactor, H+ enters the cathode chamber through the proton exchange membrane to undergo reduction reaction. The complex of SOB and Epigallocatechin-3-gallate (EGCG) was prepared on the basis of electrochemical treatment (ESOB-EGCG). The effects of two treatment on the structure and thermal properties of SOB protein were analyzed, which provided a basis for the study on the emulsification, rheological and oxidation stability of SOB emulsion. The results showed that the EAI of ESOB-EGCG was 108% higher than that of SOB, and the emulsion showed greater viscosity and the largest linear viscoelastic region. Through the determination of oxidation stability and fitting of oxidation kinetic model, it was found that ESOB-EGCG sample showed the best oxidation stability, which provided support for fitting and predicting the oxidation stability of SOB.

Construction of soybean oil bodies–xanthan gum composite oleogels by emulsion-templated method: Preparation, characterization, and stability analysis

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.

Preparation and Application of Edible Film Based on Sodium Carboxymethylcellulose-Sodium Alginate Composite Soybean Oil Body

In the study, edible films were successfully prepared by incorporating soybean oil body (SOB) into sodium alginate-sodium carboxymethyl cellulose (SA-CMC) matrix. The effects of different concentrations (0–4% w/w) of SOB on the physicochemical and antioxidant activities of films were systematically evaluated based on mechanical strength, barrier properties, thermal stability, and preservation effect. Findings revealed that the oxidation resistance, water vapor barrier, and thermal stability enhanced after the addition of SOB, while the water content, water solubility, and swelling rate decreased. When 3% SOB was added, the edible film performed the best in terms of mechanical properties and thermal stability; water vapor permeability was reduced by 21.89% compared to the control group, and the fresh life of pigeon meat was extended by 5–7 days. Fourier transform infrared spectroscopy (FTIR) and scanning electron microscopy (SEM) analyses showed that the addition of SOB results in a more stable molecular structure network, which improved its physical properties. Overall, the findings indicated that SOB improved the quality of edible films as an environmentally friendly food packaging material and increased the feasibility of edible film application in the food industry.

Effect of Heat Treatment on the Digestive Characteristics of Different Soybean Oil Body Emulsions.

Soybean oil body (SOB) emulsions were prepared using OBs extracted at pH 11.0 and pH 7.0. The pH 11.0-SOB comprised oleosins, whereas pH 7.0-SOB comprised extrinsic proteins and oleosins. All SOB emulsions were heated at 60-100 °C for 15 min. Heating may lead to the release of extrinsic proteins from the surface of pH 7.0-SOB due to heat-induced denaturation. The total proportion of α-helix and β-sheets gradually decreased from 77 (unheated) to 36.2% (100 °C). During stomach digestion, the extrinsic protein hydrolysis of heated pH 7.0-SOB emulsions was fast between 60 and 80 °C, and it then slowed between 90 and 100 °C; heating inhibited the oleosin hydrolysis of pH 7.0- and 11.0-SOBs. Heat treatment promoted aggregation and coalescence, and it resulted in increased particle sizes for all emulsions. Larger aggregates were found in heated pH 7.0-SOB emulsions, and larger oil droplets were found in heated pH 11.0-SOB emulsions. After intestinal digestion, the droplets of all SOB emulsions gradually dispersed, and particle sizes decreased. Different heating temperatures had lesser effects on particle sizes and microstructures. Lipolysis was affected by the extraction pH and heating. For pH 11.0-SOB emulsions, the FFA release tendency was greatly affected by the heating temperature, and heating to 80 °C resulted in the highest FFA release (74%). However, all pH 7.0-SOB emulsions had similar total FFA releases. In addition, the droplet charges of heated pH 7.0-SOB emulsions were lower than those of unheated pH 7.0-SOB emulsions in both the intestine and stomach phases; however, the charge changes in different pH 11.0-SOB emulsions showed the opposite tendency. This study will offer guidance regarding the application of SOB emulsions in food.

Preparation and digestive characteristics of myricitrin-loaded nanoemulsion delivery systems with glycated soybean oil body and κ-carrageenan as emulsifiers

Myricitrin (MYR) exhibits anxiolytic, analgesic, anti-inflammatory, antioxidant, hypoglycemic and antiapoptotic activities, but its use in food is currently limited due to poor water solubility, low bioavailability and chemical instability. In order to improve the MYR bioavailability, the soybean oil body (SOB) and its glycated forms were firstly used as emulsifiers to prepare four MYR nanoemulsions: (1) MYR/SOB-e: MYR monolayer nanoemulsions with SOB; (2) MYR/G-SOB-e: MYR monolayer nanoemulsions with the soy soluble polysaccharide (SSPS) glycated SOB; (3) MYR/SOB/κ-Car-e: MYR bilayer nanoemulsions with SOB and κ-carrageenan (κ-Car); (4) MYR/G-SOB/κ-Car-e: MYR bilayer nanoemulsions with soybean glycated SOB and κ-Car. The sizes, zeta potentials and microstructures of MYR nanoemulsions were examined to determine hydrolysis during gastrointestinal digestion and MYR bioavailability. The results showed that the bioavailabilities of emulsions prepared from glycated SOB were generally higher than those of emulsions prepared from unglycated SOB (p < 0.05). The highest bioavailability was 19.09% for MYR/G-SOB/κ-Car-e when κ-Car was of 2 mg/mL, which was much higher than the MYR/SOB-e bioavailabilities of 10.77%. In addition, MYR/G-SOB-e and MYR/G-SOB/κ-Car-e were stable and not visually changed after 14 days of storage, suggesting that the glycated SOB effectively improved the storage stabilities of MYR nanoemulsions.

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

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

Recovery of proteins from soybean oil-body wastewater at various pH levels and their structural and functional characterization

Soybean oil-body extraction produces large amounts of protein-containing wastewater, which wastes proteins and pollutes the environment. Herein, we investigated protein recovery from the wastewater generated during soybean oil-body production using the alkaline-extraction–isoelectric-point-precipitation method at various alkaline pH levels. We also investigated the effects of varying alkaline-extraction pH on the basic composition and physicochemical, rheological, and thermal properties of the recovered proteins. The basic composition showed that protein recovery increased with increasing pH, with a 58.88% recovery at pH 11, and that protein purity decreased above pH 10. Structural analysis using FT-IR spectroscopy showed that the α-helix predominance decreased with increasing pH, while β-sheet predominance exhibited the opposite trend. Proteins recovered at pH 8 and 9 were more soluble than those recovered at pH 10 and 11. Proteins recovered at pH 9 exhibited the highest emulsification (p < 0.05) while those recovered at pH 11 afforded the best gelation. The extraction pH has an essential effect on the structural and functional properties of proteins; maximizing value and minimizing waste during soybean processing by recovering functional proteins from wastewater are industrially applicable.

Effect of maltodextrin on the oxidative stability of ultrasonically induced soybean oil bodies microcapsules.

Encapsulation of soybean oil bodies (OBs) using maltodextrin (MD) can improve their stability in different environmental stresses and enhance the transport and storage performance of OBs. In this study, the effects of different MD addition ratios [OBs: MD = 1:0, 1:0.5, 1:1, 1:1.5, and 1:2 (v/v)] on the physicochemical properties and oxidative stability of freeze-dried soybean OBs microcapsules were investigated. The effect of ultrasonic power (150-250 W) on the encapsulation effect and structural properties of oil body-maltodextrin (OB-MD) microcapsules were studied. The addition of MD to OBs decreased the surface oil content and improved the encapsulation efficiency and oxidative stability of OBs. Scanning electron microscopy images revealed that the sonication promoted the adsorption of MD on the surface of OBs, forming a rugged spherical structure. The oil-body-maltodextrin (OB-MD) microcapsules showed a narrower particle size distribution and a lower-potential absolute value at an MD addition ratio of 1:1.5 and ultrasonic power of 250 W (32.1 mV). At this time, MD-encapsulated OBs particles had the highest encapsulation efficiency of 85.3%. Ultrasonic treatment improved encapsulation efficiency of OBs and increased wettability and emulsifying properties of MD. The encapsulation of OBs by MD was improved, and its oxidative stability was enhanced by ultrasound treatment, showing a lower hydrogen peroxide value (3.35 meq peroxide/kg) and thiobarbituric acid value (1.65 μmol/kg). This study showed that the encapsulation of soybean OBs by MD improved the stability of OBs microcapsules and decreased the degree of lipid oxidation during storage. Ultrasonic pretreatment further improved the encapsulation efficiency of MD on soybean OBs, and significantly enhanced its physicochemical properties and oxidative stability.

Stabilization of soybean and peanut oil bodies using apple pectin under acidic conditions

Soybean and peanut oil bodies (OBs) receive considerable interest in the food, cosmetic, and pharmaceutical industries. However, they aggregate easily because of their low ζ-potentials and weak electrostatic repulsion. Therefore, this study aimed to improve their stabilities using apple pectin (AP) under acidic conditions (pH 3.0, 5.0, and 7.0). The combined influences of pH and AP concentration on the interfacial proteins and rheological and physical properties were assessed. An AP concentration of 0.05% significantly reduced the storage stability of OBs at pH 3.0 (P < 0.05). The storage and oxidative stabilities of the emulsions with AP concentration ≥ 0.15% were improved by increasing the ζ-potential and apparent viscosity and decreasing the mean particle diameter. When the AP concentration was between 0.3% and 0.5%, the influence of AP on the stability of emulsion was steady. AP decreased the content of extrinsic proteins and increased the apparent viscosity. The emulsion showed superior stability at pH 5.0. Our findings indicate that AP exhibits potential as an OB stabilizer and may be used in yogurt-like foods and acidic dressings.

Digestive characteristics of oil body extracted from soybean aqueous extract at different pHs

Soybean oil bodies (SOBs), a natural source of pre-emulsified oil, have important potential applications in food industry. In this study, SOBs were extracted from raw soybean milk at pH 5.0, 7.0, 8.0, 9.0 and 11.0. The pH 5.0-, 7.0- and 8.0-SOB contained extrinsic proteins (mainly 7S, 11S and γ-conglycinin) and oleosins (24 kDa, 18 kDa and 16 kDa), and pH 9.0-, 11.0-SOB only had oleosins. Extrinsic protein contents decreased from 83.9% at pH 5.0-SOB to 58.2% at pH 8.0-SOB, zeta potentials increased gradually from –21.7 mV to –14.67 mV and particle sizes decreased from 924 nm to 359 nm with increasing extraction pHs. In stomach digestion, oleosins of pH 5.0-, 7.0-, 8.0-SOB were hydrolyzed more rapidly than extrinsic proteins. All 24 kDa oleosins were hydrolyzed during 5 min, and 18 kDa oleosins were completely hydrolyzed at 30 min for all SOBs. Oleosins were hydrolyzed and produced <15 kDa pepsin-resistant peptides. In addition, some 7S and 11S of pH 5.0-, 7.0-, 8.0-SOB resisted pepsin hydrolysis. For all SOB emulsions, zeta potentials decreased and the droplets sizes increased significantly (P < 0.05) with the extension of gastric digestive time. The oil droplets of all SOB emulsions aggregated, and the coalescence of oil droplets more easily occurred in pH 9.0- and 11.0-SOB emulsions. During the intestinal phase, zeta potentials and diameters of the droplets decreased gradually, and the droplets of SOB emulsions dispersed according to the CLSM. FFA release rates of pH 5.0-, 7.0-, 8.0-SOB emulsions increased rapidly and then increased slowly, however, the release tendency of pH 9.0-, 11.0-SOB emulsions were opposite. Total FFA releases of pH 5.0-, 7.0-, 8.0-, 9.0-, 11.0-SOB emulsions were respectively 52.5%, 70.5%, 59%, 48.8%, 43.3% at 180 min. Therefore, the digestive behaviors of SOB emulsions extracted at different pHs were different. This study will provide guidance for SOB products.

Soybean-Oil-Body-Substituted Low-Fat Ice Cream with Different Homogenization Pressure, Pasteurization Condition, and Process Sequence: Physicochemical Properties, Texture, and Storage Stability.

The purpose of this research was to explore the impacts of different homogenization pressures, pasteurization conditions, and process sequence on the physical and chemical properties of soybean oil body (SOB)-substituted low-fat ice cream as well as the storage stability of SOB-substituted ice cream under these process parameters. With the increase of homogenization pressure (10–30 MPa), the increase of pasteurization temperature (65 °C for 30 min–85 °C for 15 min), and the addition of SOB before homogenization, the overrun and apparent viscosity of ice cream increased significantly, and the particle size, hardness, and melting rate decreased significantly. Thus, frozen dairy products of desired quality and condition could be obtained by optimizing process parameters. In addition, the SOB ice cream showed better storage stability, which was reflected in lower melting rate and hardness and more stable microstructure compared with the full-milk-fat ice cream. This study opened up new ideas for the application of SOB and the development of nutritious and healthy ice cream. Meanwhile, this research supplied a conceptual basis for the processing and quality optimization of SOB ice cream.

Low-cholesterol-low-fat mayonnaise prepared from soybean oil body as a substitute for egg yolk: The effect of substitution ratio on physicochemical properties and sensory evaluation

Due to the higher fat and cholesterol content in egg yolks, it is urgent to explore egg yolk substitutes in mayonnaise. Soybean oil body (SOB) has the potential to be a substitute for egg yolk due to its stable natural emulsifying properties. Therefore, this study investigated the effects of different ratios of SOB (10%–50%) substitution for egg yolk on the physicochemical, texture, flavor, sensory and digestive properties of mayonnaise. It was found that when SOB substituted for 50% of egg yolk, the cholesterol content per 100 g of mayonnaise sample was decreased from (124.10 ± 3.81) mg to (48.25 ± 1.44) mg, and the fat content decreased from (53.15 ± 0.24)% to (44.09 ± 0.38)%. Although, the higher moisture content in SOB resulted in a decrease in apparent viscosity and stability of the mayonnaise samples, the sensory score of mayonnaise with SOB substituted for 20% of egg yolk was not significantly different from that of the mayonnaise without SOB substitution (p > 0.05). Furthermore, SOB-substituted mayonnaise has health benefits by releasing more antioxidant active components during digestion, compared to whole egg yolk mayonnaise. Therefore, SOB has potential as an egg yolk substitute for the development of functional low-fat mayonnaise.

Physicochemical Properties, Stability and Texture of Soybean-Oil-Body-Substituted Low-Fat Mayonnaise: Effects of Thickeners and Storage Temperatures.

With the increasing consumer demand for low-fat and low-cholesterol foods, low-fat mayonnaise prepared from soybean oil body (SOB) substitute for egg yolk has great consumption potential. However, based on previous studies, it was found that the stability and sensory properties of mayonnaise substituted with SOB were affected due to there being less lecithin and SOB containing more water. Therefore, this study investigated the effects of different ratios of xanthan gum, pectin and modified starch as stabilizers on the apparent viscosity, stability, texture and microstructure of SOB-substituted mayonnaise. It was found that the apparent viscosity and stability of SOB-substituted mayonnaise increased significantly when xanthan gum, pectin and modified starch were added in a ratio of 2:1:1. Meanwhile, the emulsified oil droplets of SOB-substituted mayonnaise were similar in size and uniformly dispersed in the emulsion system with different thickener formulations. In addition, the storage stability of SOB-substituted mayonnaise was explored. Compared with full egg yolk mayonnaise, SOB-substituted mayonnaise had better oxidative stability and bacteriostatic, which is important for the storage of mayonnaise. This study provided a theoretical basis for the food industry application of SOB. Meanwhile, this study provided new ideas for the development and storage of low-fat mayonnaise.

Soybean Oil Bodies as a Milk Fat Substitute Improves Quality, Antioxidant and Digestive Properties of Yogurt.

In this experiment, the effect of replacing milk fat with soybean fat body (25%, 50%, 75%, 100%) on the quality, antioxidant capacity and in vitro digestive characteristics of yogurt was investigated while maintaining the total fat content of the yogurt unchanged. The results showed that increasing the substitution amount of soy fat body for milk fat had little effect on the pH and acidity of yogurt during the storage period, while the physicochemical properties, degree of protein gel network crosslinking, saturated fatty acid content, PV value and TBARS value of the yogurt significantly decreased (p < 0.05). Meanwhile, protein content, solids content, unsaturated fatty acid content, tocopherol content and water holding capacity significantly increased (p < 0.05). Flavor analysis revealed that yogurts with soybean oil bodies were significantly different when compared to those without soybean oil bodies (p < 0.05), and yogurt with 25% substitution had the highest sensory score. After in vitro digestion, the free fatty acid release, antioxidant capacity and protein digestibility of soybean oil body yogurt were significantly higher (p < 0.05). The SDS-PAGE results showed that the protein hydrolysis of the soybean oil body yogurt was faster. Therefore, the use of an appropriate amount of soybean oil bodies to replace milk fat is able to enhance the taste of yogurt and improve the quality of the yogurt.

Effects of Soybean Oil Body as a Milk Fat Substitute on Ice Cream: Physicochemical, Sensory and Digestive Properties.

Soybean oil body (SOB) has potential as a milk fat substitute due to its ideal emulsification, stability and potential biological activity. In this study, SOB was used as a milk fat substitute to prepare ice cream, expecting to reduce the content of saturated fatty acid and improve the quality defects of ice cream products caused by the poor stability of milk fat at low temperatures. This study investigated the effect of SOB as a milk fat substitute (the substitution amount was 10–50%) on ice cream through apparent viscosity, particle size, overrun, melting, texture, sensory and digestive properties. The results show SOB substitution for milk fat significantly increased the apparent viscosity and droplet uniformity and decreased the particle size of the ice cream mixes, indicating that there were lots of intermolecular interactions to improve ice cream stability. In addition, ice cream with 30% to 50% SOB substitution had better melting properties and texture characteristics. The ice cream with 40% SOB substitution had the highest overall acceptability. Furthermore, SOB substitution for milk fat increased unsaturated fatty acid content in ice cream and fatty acid release during digestion, which had potential health benefits for consumers. Therefore, SOB as a milk fat substitute may be an effective way to improve the nutritional value and quality characteristics of dairy products.

Oil bodies extracted from high-oil soybeans (Glycine max) exhibited higher oxidative and physical stability than oil bodies from high-protein soybeans.

Reports concerning the characteristics of soybean oil bodies (SOBs) isolated from high protein genotypes and high oil genotypes of soybeans available in the literature are insufficient and limiting. In this study, fatty acid compositions, total phenol and tocopherol contents, antioxidant capacity, and physicochemical stability of SOB emulsions recovered from three high-protein and three high-oil genotype soybeans were comparatively investigated. Principal component analysis showed that all six SOB samples could be easily discriminated based on the cultivar characteristics. Overall, the SOBs derived from the high-protein soybeans exhibited higher polyunsaturated fatty acid (PUFA) contents, while the SOBs derived from the high-oil soybeans had higher extraction yields and tocopherol contents; the tocopherol content was also positively correlated with the antioxidant capacity of the lipophilic fraction, but the difference in the total phenolic content between the two genotypes was not significant. The SOBs derived from the high-protein soybeans were more easily oxidized during storage, with 1.38- and 4-fold higher accumulation rates of lipid hydroperoxides (LPO) and thiobarbituric acid reactive substances (TBARS), respectively, in the high-protein-derived SOBs than in the high-oil-derived SOBs. In addition, the SOBs from the high-protein soybeans exhibited pronounced coalescence during storage, which was corroborated by focused confocal microscopy. These results confirmed that SOBs obtained from high-oil soybean genotypes are more suitable to manufacture OB-based products due to their superior physicochemical stability.

NaCl induces flocculation and lipid oxidation of soybean oil body emulsions recovered by neutral aqueous extraction.

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. This study investigated the effect of NaCl (0-1.2%) on the physical and oxidative stability of SOB emulsions under neutral (pH7) and acidic (pH3) conditions. In the presence of NaCl, the SOB emulsion (pH7) showed strong flocculation during storage due to electrostatic screening. The NaCl-induced flocculation of SOB was attenuated at pH3, 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 pH3. 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.

Oil Body Emulsion after Soybean Seed Germination Study on Stability

Soybean was used as raw material, and the oil emulsion of soybean seeds after germination was taken as the research object. Measurement of emulsion stability, peroxide value, thiobarbituric acid value (TBARS value) and acid value, the stability of oil emulsion of soybean seeds at different germination times was compared, and the effects of different treatment conditions (NaCl concentration, pH and storage temperature) on the stability of oil emulsion of soybean seeds after germination were studied. The experimental results showed that the oil bodies extraction rate of soybean seeds decreased gradually after germination, There was no significant difference in the extraction rate between 20 h (12.36%±0.21%) and 27 h (10.89%±0.28%) (P>0.05), and the extraction rate decreased significantly after 27 h (P 0.05). The emulsifying stability showed a downward trend when NaCl concentration was 0~150 mmol/L, and no significant change when NaCl concentration was higher than 150 mmol/L. The emulsifying stability was (4.75±0.12) min and (4.74±0.14) min when NaCl concentration was 150 and 200 mmol/L, respectively. However, the peroxide value increased significantly during 0~6 d of storage (P<0.05).The higher the pH was, the smaller the ζ-potential and emulsifying activity of the emulsion were. When the pH was 4, the emulsifying activity was (19.13±0.23) m2/g, and the peroxide value and TBARS value changed significantly (P<0.05). The emulsion stability of soybean seed oil body at different germination time was different, and soybean oil body after 27 h germination was more stable than other germination time. NaCl concentration and pH had great effect on the stability of germinated soybean oil emulsion, and storage temperature had little effect on it. It could provide theoretical basis for the application of germinated soybean oil bodies in the future.