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This study aimed to explore the effect of ultrasound-assisted pH shift on the structural and functional properties of soybean lipophilic proteins (SLP). SLP were modified under ultrasound (240 W, 20 min) and extreme pH (pH 1 or 12) conditions. The primary, secondary and tertiary structures of native and modified SLP were characterized by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE), free sulfhydryl content, Fourier transform infrared (FTIR) spectroscopy, and fluorescence spectroscopy, and their functional properties were analyzed. The results showed that ultrasound-assisted alkaline pH shift resulted in the greatest changes in the structural and functional properties of SLP. The average particle size of SLP decreased from 5 245.33 to 447.13 nm, the ζ-potential value decreased from − 5.95 to − 18.53 mV, the free sulfhydryl content decreased, the α-helix content increased, and the fluorescence spectrum exhibited a blue shift and a decrease in fluorescence intensity. In addition, the solubility increased from 9.84% to 92.04%, and the emulsifying and foaming properties increased. Therefore, ultrasound and pH shift treatments have a synergistic effect on the structural and functional properties of SLP, and they are closely correlated with each other.

The purpose of this study was to understand the stability of natural emulsions formed from soybean oil bodies (SOB) extracted at alkaline pH (8.0–11.0) and their digestive properties in the gastrointestinal tract. The stability of SOB was evaluated in terms of its basic composition, particle size, zeta potential and rheology, and the digestive properties were evaluated in terms of fatty acid release from SOB and the microstructure of SOB. The results showed that with an increase in extraction pH, the water and protein contents of SOB decreased and the particle size decreased from (471.57 ± 8.53) nm to (424.77 ± 12.21) nm, while the lipid content increased. In addition, the oxidative stability of SOB showed a similar trend. Specifically, the peroxide value (POV) decreased with increasing extraction pH and the thiobarbituric acid reactive substances (TBARS) value increased with an increase in storage time. The apparent viscosity decreased with increasing shear rate. SOB emulsions showed shear thinning behavior with G’ being greater than G” for all samples, and the release percentage of free fatty acids from SOB significantly increased with increasing extraction pH (P < 0.05). This study provides theoretical support for the wide application of highly stable natural SOB.

Intraseasonal variabilities (ISVs) of the western boundary currents (WBCs) east of Luzon Island were explored using acoustic Doppler current profiler (ADCP) measurements from three moorings at 18°N during 2018–2020. Besides the traditionally known surface‐intensified ISV, subsurface‐intensified ISV with a typical period of approximately 60 days was also detected in the currents, and the strongest signal appeared between 400 and 800 m. Further analysis indicates that they are highly associated with subsurface eddies. Based on their lifespan, subsurface eddies are classified into two categories: short‐lived and medium‐to long‐lived eddies. The short‐lived eddies are primarily generated locally near the eastern coast of Luzon Island, whereas the medium‐to long‐lived eddies are mainly generated away from the western boundary, in the region west of 135°E. Additional energy diagnosis suggests that baroclinic instability induced by the velocity shear of the North Equatorial Current (NEC)/subtropical countercurrent (STCC) system dominates the generation of medium‐to long‐lived subsurface eddies in the interior ocean, while barotropic instability and baroclinic instability play a comparable role in the generation of short‐lived eddies near the eastern coast of Luzon Island. Plain Language Summary: The Kuroshio and Luzon Undercurrent (LUC) have a far‐reaching impact on regional climate change as a crucial part of the western boundary current (WBC) system. In situ measurements east of Luzon Island have revealed that the currents exhibit significant intraseasonal variabilities (ISVs). However, the vertical difference of the ISVs is unclear, and we still do not know if subsurface ISVs exist in this region. In this work, we found the currents east of Luzon Island are characterized by two types of ISVs with a period of approximately 60 days: surface‐intensified and subsurface‐intensified. The two types of ISVs are linked to the surface and subsurface mesoscale eddies, respectively. Previous studies have revealed that baroclinic instability associated with the vertical shear of velocity in the North Equatorial Current/subtropical countercurrent (NEC/STCC) system is the primary generation mechanism of surface eddies. This study suggests that baroclinic instability of the NEC/STCC system also dominates the generation of subsurface eddies in the interior ocean, while barotropic instability associated with the horizontal shear of currents near the Luzon coast is non‐negligible in the generation of coastal subsurface eddies. These results significantly deepen our understanding of the ISVs of the currents in this region. Key Points: Quasi‐60‐day intraseasonal variability in the currents east of Luzon Island exhibits surface‐ and subsurface‐intensified vertical featuresSubsurface‐intensified eddies are revealed appearing east of Luzon Island and modulating the western boundary currentsBaroclinic instability dominates the generation of subsurface eddies east of Luzon while coastal barotropic instability is non‐negligible [ABSTRACT FROM AUTHOR]

In this study, soybean oil bodies were used as raw materials and emulsifiers to prepare soybean oil body complex emulsions by ultrasonication, to optimise the ultrasonication conditions and to use the oil body complex emulsions for the transport of fat-soluble bioactives. The mechanism of ultrasonic treatment to enhance the stability of oil-body complex emulsions was revealed through the study of the physicochemical properties of the emulsions. The effect of oil-body complex emulsions on the transport of β-carotene was also examined. As a result, soybean oil body complex emulsion was successfully prepared by ultrasonication, and the oxidative and storage stability of the emulsion was best at a power of 450 W (10 min). At this time, the average particle size of emulsion was 1537 nm, and the shape of droplets was round and evenly distributed. The results of Fourier transform infrared spectroscopy indicated that the ultrasound-induced cavitation effect increased the physical forces, such as turbulence and shear forces. This caused partial unfolding of the protein polypeptide chains in oil bodies, leading to the rearrangement of hydrogen bond networks within the proteins. Consequently, the protein secondary structure changed: The relative content of α-helix structures decreased and the relative content of β-sheet structures increased. The electrophoresis results showed that there were no significant changes in the composition of protein subunits. But with the ultrasound intensity increased, the adsorption of extrinsic proteins at the droplet interface was enhanced. The results of storage stability showed that ultrasonic treatment (450 W) could inhibit the generation of oxidation products and improved the oxidation stability of emulsions. The soybean oil body-β-carotene emulsions could be successfully prepared by ultrasonic treatment, and the encapsulation rate of β-carotene was the highest (94.9%) at 450 W, and the retention rate was 81.8% after 11 days of room temperature storage. This study provides insights into the application of soybean oil bodies as emulsifiers for the delivery of fat-soluble bioactive substances. [ABSTRACT FROM AUTHOR]

In this study, we developed an approach by coating silica nanospheres with polydopamine and metal precursor, followed by carbonization to create interfacial engineered MoO2. The presence of numerous crystal interfaces and metal–carbon interactions resulted in a remarkable enhancement of C–N coupling activity and stability of catalyst compared to one obtained by air calcination. [ABSTRACT FROM AUTHOR]