3D confocal Raman imaging of oil-rich emulsion from enzyme-assisted aqueous extraction of extruded soybean powder

Stabilization of calcium-fortified soy protein emulsions by calcium chelating agent sodium tripolyphosphate

Calcium-fortified soy protein emulsions stabilized by sodium tripolyphosphate are of considerable importance for the development of calcium-fortified soymilk products. This study aimed to investigate the characteristics and stabilities of calcium-fortified soy protein emulsions stabilized by sodium tripolyphosphate. When the concentration of sodium tripolyphosphate ranged from 0 to 0.6%, the emulsion potential and emulsification activity index gradually increased to 35.5 mV and 71.7 ± 0.8%, while the particle size and flocculation index progressively decreased to 756.2 ± 41.3 nm and 16.21%, respectively. However, when the concentration exceeded 0.6%, these characterization data plateaued. Microstructural analysis revealed a uniform distribution of droplets. Raman spectroscopy showed an increase in the ordered structure of proteins in the emulsion. Additionally, the centrifugal, thermal, and storage stabilities of the emulsion were enhanced. These findings offer insights into the properties of calcium-fortified soy protein emulsions stabilized by sodium tripolyphosphate and may contribute to expanding their utilization in emulsions and soy products.

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Enhancing emulsification properties of pea protein isolate: Impact of heat treatment and soy hull polysaccharides on conformational modification and stability

In order to investigate the effect of conformational change in pea protein isolate (PPI) on its emulsification properties, soy hull polysaccharides (SHP) were added to modify the conformation following heat treatment at 70-100 °C to improve emulsification. The results of UV and fluorescence spectroscopy indicated that the heat treatment exposed the amino acid residues to a more hydrophobic environment. The mean volume diameter (d4,3) of PPI was reduced from 67.25 ± 3.31 to 45.50 ± 0.62 μm, and secondary structure of protein became more ordered. The addition of SHP enhanced the adsorption of protein at the oil-water interface and reduced the interfacial tension. Interestingly, SHP decreased the short-term (12h) thermal stability index (TSI) from 3.5 to 2.8 in PPI/SHP emulsion treated at 100 °C. These findings validated that heat treatment combined with SHP modification can improve the emulsification of PPI, which positively impacts the development of pea-based products for high temperatures applications.

Impact of trypsin on interfacial conformational evolution of soy protein isolate/soy hull polysaccharide emulsion

The impact of trypsin on the demulsification mechanism of soy protein isolate (SPI)/soy hull polysaccharide (SHP) emulsion under trypsin treatment was investigated. We analyzed the conformational evolution of the emulsion interface induced during the bulk demulsification, focusing on the oil-water interface. During the enzymatic treatment for 0-120 min, various spectral analyses including spectrum analyses of Raman, FT-IR, intrinsic fluorescence, and ultraviolet spectral analyses demonstrated gradual hydrolysis and polymerization of protein molecules within SPI/SHP, SPI, and SHP on the oil-water interface by trypsin, particularly noticeable during 30-90 min. Notably, at 90 min, an increase in β-sheet content and a red shift of the IR spectrum from 3400 to 3380 cm-1 indicated the conjugate effect of small molecules due to large interfacial tension, accompanied by hydrophobic interaction and hydrogen bonding. These alterations in SPI/SHP, SPI, and SHP conformations at the oil-water interface led to droplet demulsification and oil phase release.

Dynamic analysis of bovine bone high-temperature hydrolysate emulsion formation based on microstructure and physicochemical interactions

In the food industry, the emulsifying process alters both the stability and quality of the emulsified products prepared by bovine bone high-temperature hydrolysate (BBHH). The microstructure and interactions of BBHH emulsion were characterized by cryo-scanning electron microscopy (Cryo-SEM) and Raman spectroscopy during emulsification. Notably, BBHH emulsion exhibited the best properties under emulsifying for 120 s, attributed to its interfacial adsorption characteristics. In terms of microstructure, the droplets were small and uniform, and the cross-linking and network structure between the droplet surfaces were obvious at 120 s. Raman spectroscopy indicated that the adsorption of BBHH at the oil-water interface mainly involved an increase of the β-sheet at the expense of the α-helix region. In addition, protein adsorption and structural development at the interface were driven by hydrophobic interactions, while further rearrangement and polymerization were mediated by disulfide bonds. Furthermore, the stability and particle size distribution of the emulsion also supported the results. This study provided a theoretical basis for the behavior of BBHH emulsion formation, which expanded valuable insights into the mechanisms by which liquid food emulsification systems mediated by animal-derived proteins and how they behave under a variety of external conditions.

Improving emulsion stability: The role of flaxseed gum in stabilizing bovine bone protein hydrolysates emulsions

The use of natural proteins as emulsifiers in stable emulsion systems has gained attention due to the increasing demand for healthy food products. However, the limited thermal stability and ionic tolerance of BBPH restrict its application in emulsions. This study explores the effects of FG on enhancing the stability of BBPH-based emulsions. FTIR and SEM confirmed that BBPH and FG form complexes through hydrophobic and electrostatic interactions, with increasing FG concentrations leading to higher turbidity and particle size. At 0.4 % FG, emulsions showed the smallest particle size (9.12 μm) and the highest zeta potential (-28.73 mV), indicating optimal interaction. Raman spectroscopy further supported these findings, showing enhanced oil-complex interactions and favorable rheological properties. The emulsions exhibited excellent stability during storage, with a creaming index of 1.786 % after 7 days. Oxidation tests showed low POV (0.596 mg/L) and TBARS (6.24 mg/L) after 15 days. FG also improved resistance to environmental stress, providing theoretical support for the broader use of BBPH in the food industry and highlighting FG's potential in stabilizing protein-based emulsions.

Determination of the effects of novel paraprobiotic supplement of Lactobacillus plantarum on soy dairy-free beverage by physicochemical, antioxidant, sensory analyses, and Raman spectroscopy technique

Paraprobiotics are inactivated microbial cells that improve the health status of consumers when taken in adequate doses. They can be used instead of probiotics to eliminate disadvantages such as instability in production and storage difficulties. They can also be an alternative nutritional supplement for individuals sensitive to fermented products. In this study, a paraprobiotic supplement obtained from Lactobacillus plantarum was added to a soy dairy-free beverage at two concentrations of 108 and 109 CFU/mL. Then, total soluble solids, pH, color, titratable acidity, antioxidant activity, and total phenolic content of the beverage were measured, and sensory analysis was also performed. The results indicate that paraprobiotic addition significantly increased (p < 0.05) the antioxidant activity (75.44 ± 0.23 µmol TE/g sample), total phenolic content (834.32 ± 6.69 mg GAE/g), protein (3.28 ± 0.18%), fat (2.35 ± 0.06), and ash content (0.57 ± 0.08). These results were also validated using the Raman spectroscopy technique. The paraprobiotic-supplemented soy dairy-free beverage had the highest taste and overall impression values. Since the parabiotic addition did not affect the physicochemical properties of the beverage, manufacturers can develop commercial products containing paraprobiotics without altering the production process. PRACTICAL APPLICATION: Paraprobiotics provide an alternative for individuals sensitive to fermented products but still desire the health benefits of probiotics. They additionally provide practical and technological advantages, including a longer shelf life without a need for a cold chain to preserve the viability and stability of microorganisms. The results of this study can be a reference for the industry to develop food products containing paraprobiotics with increased antioxidative and nutritional properties.

Ultrasonic-assisted green extraction and incorporation of Spirulina platensis bioactive components into turmeric essential oil-in-water nanoemulsion for enhanced antioxidant and antimicrobial activities

The utilization of essential oils as natural antioxidants and preservatives is limited by high volatility, poor water solubility, and long-term instability. To address this, a novel ultrasonic-assisted method was used to prepare and stabilize a nanoemulsion of turmeric essential oil-in-water, incorporating bioactive components extracted from Spirulina platensis. Ultrasonic treatment enhanced the extraction efficacy and nanoemulsion stability. Algal biomass subjected to ultrasonic treatment (30 min at 80% amplitude) yielded a dry extract of 73.66 ± 3.05%, with the highest protein, phenolic, phycocyanin, and allophycocyanin content, as well as maximum emulsifying activity. The resulting nanoemulsion (5% oil, 0.3% extract, 10 min ultrasonic treatment) showed reduced particle size (173.31 ± 2.24 nm), zeta potential (-36.33 ± 1.10 mV), low polydispersity index, and enhanced antioxidant and antibacterial properties. Rheology analysis indicated shear-thinning behavior, while microscopy and spectroscopy confirmed structural changes induced by ultrasonic treatment and extract concentration. This initiative developed a novel ultrasonic-assisted algal-based nanoemulsion with antioxidant and antibacterial properties.

Effect of a collagen peptide-fish oil high internal phase emulsion on the printability and gelation of 3D-printed surimi gel inks

The effect of a high internal phase emulsion (HIPE) on three-dimensional-printed surimi gel inks was studied. Increasing the concentration of collagen peptide decreased the particle size of HIPE droplets and improved the viscoelasticity and stability. For example, when the collagen peptide concentration was 5 wt%, the viscoelasticity of the HIPE was high, as indicated by the presence of small and uniform particles, which formed a monolayer in the outer layer of the oil droplets to form stable a HIPE. A HIPE was used as the filling material to fill the surimi gel network, which reduced the porosity of the network. Surimi protein and peptides have dual emulsifying effects on the stabilization of oil. After adding the emulsion, the texture, gel properties and rheological properties of the surimi were reduced, and its printing adaptability was improved. This study provides new ideas for the production of surimi and its application in 3D printing.

Raman Spectroscopy of Emulsions and Emulsion Chemistry

Emulsions are dispersed systems widely used in various industries. In recent years, Raman spectroscopy (RS), as a spectroscopic technique, has gained much attention for measuring and monitoring emulsions. In this review, we explore the use of RS on emulsion structures and emulsification, important reactions that use emulsions such as emulsion polymerization, catalysis and cascading reactions, as well as various applications of emulsions. We explore how RS is used in emulsions, reactions and applications. RS is a powerful and versatile tool for studying emulsions, but there are also challenges in using RS to monitor emulsion processes, especially if they are rapid or volatile. We also explore these challenges and difficulties, as well as possible designs that can be used to overcome them.

Disposable face masks release micro particles to the aqueous environment after simulating sunlight aging: Microplastics or non-microplastics?

This study focuses on characterizing microplastics and non-microplastics released from surgical masks (SMs), N95 masks (N95), KN95 masks (KN95), and children's masks (CMs) after simulating sunlight aging. Based on micro-Raman spectrum analysis, it was found that the dominant particles released from masks were non-microplastics (66.76-98.85%). Unfortunately, CMs released the most microplastics, which is 8.92 times more than SMs. The predominant size range of microplastics was 30-500 µm, and the main polymer types were PP and PET. Compared with the whole SMs, the microplastic particles released from the cutting-SMs increased conspicuously, which is 12.15 times that of the whole SMs. The main components of non-microplastics include β-carotene, microcrystalline cellulose 102, and eight types of minerals. Furthermore, non-microplastics were mainly fibrous and fragmented in appearance, similar to the morphology of microplastics. After 15 days of UVA-aging, the fibers of the face layers had cracks to varying degrees. It was estimated that these four types of masks can release at least 31.5 trillion microplastics annually in China. Overall, this study demonstrated that the masks could release a large quantity of microplastics and non-microplastics to the environment after sunlight aging, deserving urgent attention in the future study.

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

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

High-Sensitivity and Environmentally Friendly Humidity Sensors Deposited with Recyclable Green Microspheres for Wireless Monitoring

The reliable, high-sensitive, wireless, and affordable requirements for humidity sensors are needed in high-precision measurement fields. Quartz crystal microbalance (QCM) based on the piezoelectric effect can accurately detect the mass changes at the nanogram level. However, water-capture materials deposited on the surface of QCM generally show disadvantages in either cost, sensitivity, or recyclability. Herein, novel QCM-based humidity sensors (NQHSs) are developed by uniformly depositing green microspheres (GMs) of natural polymers prepared by the chemical synthesis of the emulsification/inner gel method on QCM as humidity-sensitive materials. The NQHSs demonstrate high accuracy and sensitivity (27.1 Hz/% RH) owing to the various hydrophilic groups and porous nano-3D deposition structure. Compared with the devices deposited with a smooth film, the frequency of the NQHSs shows almost no changes during the cyclic test and exhibits long-term stability. The NQHSs have been successfully applied to non-contact sensing human activities and remote real-time humidity monitoring via Bluetooth transmission. In addition, the deposited humidity-sensitive GMs and QCM substrate are fully recycled and reused (72% of the original value). This work has provided an innovative idea to construct environmental-friendly, high-sensitivity, and wireless humidity sensors.

Image of the distribution profile of targets in skin by Raman spectroscopy-based multivariate analysis

Raman spectroscopic imaging is a label-free spectral technology to investigate the distribution of transdermal targets in skin. However, it is difficult to analyze low content of analytes in skin by direct imaging analysis. Combining Raman mapping technology with multiple linear regression algorithms, concentration contribution factor of targets in ex vivo human skin tissue at every point has been calculated. The distribution profiles are visualized as heat maps demonstrating the targets levels in different skin layers. This method has been successfully employed to investigate the vibrational imaging of distribution of hyaluronic acid and lidocaine in skin. Moreover, three dimensional (3D) images of the penetration profiles of hyaluronic acid with different molecular weight have been obtained. The results from 3D images were in good agreement with these from two-dimensional images, indicating that this method was a reliable way for monitoring the distribution of targets in skin.

Effect of cavitation jets on the physicochemical properties and structural characteristics of the okara protein

The structural andphysicochemical properties of okara protein (OP) subjected to different cavitation jet (CJ) treatment times (0-15 min) were analyzed. In this study, the microstructure and apparent morphology of OP were analyzed by Raman spectrum, fluorescence spectrum, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and atomic force microscopy (AFM). Physicochemical properties, such as emulsion ability (EA), emulsion stability index (ESI), foaming characteristics (FC), foaming stability (FS), and solubility analysis of the OPs, were characterized. Raman spectrum analysis showed that CJ treatment caused increases in the ordered structure of OPs (α-helix, β-sheet, and β-turn), and the disulfide bond g-g-g and g-g-t modes, while it caused a decrease in the t-g-t mode. However, the tertiary structure of OP unfolded and mostly degraded into small subunits because of higher cavitation, shear and temperature effects. AFM observation indicated that CJ resulted in a more uniform distribution of OP. Moreover, changes in the structure of OP significantly affected its functional properties. The results showed that when CJ treatment time was 10 min, the solubility of OP was up to (28.72 ± 1.26)%, the soluble protein content of okara was up to (10.44 ± 0.03) g/100 g, and interface properties were better. In summary, OP has great potential for application in the food area, especially in emulsifying agent and foam system. PRACTICAL APPLICATION: The cavitation jet technology improves the structure and physical and chemical properties of the protein extracted from soybean residue (okara) and provides new ideas for the further development and utilization of soybean residue protein, which may lead to the production of high-value-added functional ingredients from the processing of soybean byproducts.

Latest advances in imaging techniques for characterizing soft, multiphasic food materials

Over the last two decades, the development and production of innovative, customer-tailored food products with enhanced health benefits have seen major advances. However, the manufacture of edible materials with tuned physical and organoleptic properties requires a good knowledge of food microstructure and its relationship to the macroscopic properties of the final food product. Food products are complex materials, often consisting of multiple phases. Furthermore, each phase usually contains a variety of biological macromolecules, such as carbohydrates, proteins and lipids, as well as water droplets and gas bubbles. Micronutrients, such as vitamins and minerals, might also play an important role in determining and engineering food microstructure. Considering this complexity, highly advanced physio-chemical techniques are required for characterizing the microstructure of food systems prior to, during and after processing. Fast, in situ techniques are also essential for industrial applications. Due to the wide variety of instruments and methods, the scope of this paper is focused only on the latest advances of selected food characterization techniques, with emphasis on soft, multi-phasic food materials.

Imaging Analysis Enables Differentiation of the Distribution of Pharmaceutical Ingredients in Tacrolimus Ointments

We demonstrated the difference in the distribution state of pharmaceutical ingredients between tacrolimus (TCR) original ointment and six kinds of generic medicines. Two-dimensional imaging and depth analysis using attenuated total reflection Fourier transform infrared (ATR FT-IR) spectroscopy and confocal Raman microscopy were used, in addition to the evaluation of pharmaceutical properties, including spreading properties, rheological properties, and amount of solvent. The solvents, such as propylene carbonate and triacetin, in TCR ointments formed liquid droplets and dispersed in hydrocarbon oils. Waxes, white beeswax and beeswax, formed other domains. Confocal Raman microscopy could detect liquid droplet size without coalescence of that on germanium or glass surfaces. The combination of ATR FT-IR and confocal Raman imaging would be a powerful tool to reveal the size and shape of liquid droplets of pharmaceutical ingredients in semisolid formulations.

Combination of thermal pretreatment and alcohol-assisted aqueous processing for rapeseed oil extraction

BACKGROUND

The alcohol-assisted aqueous extraction processing (AAEP) of oil has many advantages such as no need for demulsification and relative low cost compared with enzymatic aqueous extraction processing (EAEP). Three kinds of thermal pretreatments including dry-heating, wet-heating and soak-heating followed by the AAEP of rapeseed oil were investigated.

RESULTS

Both soak-heating and wet-heating had a higher contribution rate to oil yield than dry-heating due to the enhancement of heat transfer rate owing to the high moisture content in the rapeseed cells. However, oil from soak-heated rapeseeds showed a much lower level on peroxide value (0.41 mmol kg^-1 ) than that of wet-heated rapeseeds (5.23 mmol kg^-1 ). In addition, transmission electron microscopy images illustrated that promoting effects of soak-heating and wet-heating on oil release were attributed to the coalescence of oil bodies. A relative low concentration of alcohol solution as an extraction medium, the highest oil recovery of 92.77% was achieved when ground rapeseeds (mean particle size: 21.23 µm) were treated with 45% (v/v) alcohol for 2 h at 70 °C and pH 9.0. Both the acid value and the peroxide value are lower than the commercial oil produced by extrusion and hexane extraction. Furthermore, the oil produced from AAEP also had higher content of tocopherols and lower content of trans-fatty acids than the commercial oil.

CONCLUSION

AAEP of oil from soak-heated rapeseeds is a promising alternative to conventional oil extraction methods. © 2019 Society of Chemical Industry.