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In this study, rice protein was used as raw material to explore the effects of γ-irradiation treatment doses (0, 0.5, 1, 2, 3, 5 kGy) on the physicochemical properties of rice protein (particle size, zeta potential, secondary structure, scanning electron microscope microstructure), surface hydrophobicity (H 0 ), thermal stability), functional properties (solubility, water and oil retention, emulsification) and sensory quality. The results show that when the γ-irradiation dose is 2 kGy, the average particle size of rice protein is the smallest, the absolute value of the potential is the highest 33.58 mV, the content of β-sheets in the secondary structure is at least 31.16 ± 0.16, and the content of random curl is at most 14.56 ± 0.06, the surface of the microstructure is rough and the degree of pore depression is the deepest, the highest H 0 is 160.45 ± 2.98, the minimum denaturation temperature (T d ) and enthalpy (△H) are 70.49 ± 0.05 °C and 1.30 ± 0.01 J/g, which shows that γ-irradiation treatment can be significant affect the physicochemical properties of rice protein. When the irradiation dose is 2 kGy, the highest solubility of rice protein is 69.18 ± 1.07%, and the highest water and oil holding capacity are 5.89 ± 0.08 g/g and 3.45 ± 0.04 g/g, respectively. The highest emulsification activity and emulsification stability are 45.65 ± 1.26 m 2 /g and 208.33 ± 4.79 min, which shows that γ-irradiation treatment can improve the functional properties of protein. When the irradiation dose was less than 5 kGy, the sensory quality of rice protein was not significantly affected. The research results provide a theoretical basis for the deep processing and value-added utilization of rice protein by γ-irradiation technology.

Summary The objective of this study was to investigate the effects of cavitation jets on the structural, emulsifying and rheological properties of soybean protein oxidation aggregates. The results showed that oxidation might induce the formation of larger particle sizes and molecular weight protein aggregates and the decrease of emulsifying properties. The cavitation jet at a short treatment time (<6 min) broke down the disulphide bonds and protein skeleton structures, which reduced the aggregate sizes and molecular weights and increased the emulsion activities, emulsion stabilities, apparent viscosity and elastic modulus. The cavitation jet at a long treatment time (>6 min) supported disulphide bond formation among molecules by intermolecular interactions to form protein aggregates. In addition, the skeleton structure showed cross‐linking aggregation. This increased the particle sizes and molecular weights and reduced the emulsion properties, consistency index K and elastic modulus. The findings showed that a cavitation jet at 6 min on oxidised aggregates of soybean protein might enhance the structural, emulsifying and rheological characteristics for the industry.

A cavitation jet can enhance food proteins’ functionalities by regulating solvable oxidized soybean protein accumulates (SOSPI). We investigated the impacts of cavitation jet treatment on the emulsifying, structural and interfacial features of soluble soybean protein oxidation accumulate. Findings have shown that radicals in an oxidative environment not only induce proteins to form insoluble oxidative aggregates with a large particle size and high molecular weight, but also attack the protein side chains to form soluble small molecular weight protein aggregates. Emulsion prepared by SOSPI shows worse interface properties than OSPI. A cavitation jet at a short treating time (<6 min) has been shown to break the core aggregation skeleton of soybean protein insoluble aggregates, and insoluble aggregates into soluble aggregates resulting in an increase of emulsion activity (EAI) and constancy (ESI), and a decrease of interfacial tension from 25.15 to 20.19 mN/m. However, a cavitation jet at a long treating time (>6 min) would cause soluble oxidized aggregates to reaggregate through an anti-parallel intermolecular β-sheet, which resulted in lower EAI and ESI, and a higher interfacial tension (22.44 mN/m). The results showed that suitable cavitation jet treatment could adjust the structural and functional features of SOSPI by targeted regulated transformation between the soluble and insoluble components.

In this study, pea residue reserve insoluble diet fiber (hereinafter referred to as pea fiber) was used as a raw material. The effects of γ-irradiation doses (0, 0.5, 1, 2, 3, and 5 kGy) on the structural properties (main composition, particle size and specific surface area, scanning electron microscope (SEM) microstructure, Fourier transform infrared spectroscopy, and X-ray diffraction) and functional properties (oil-holding capacity, swelling and water-holding capacity, and adsorption properties) of pea fiber were explored. The results show that, when the γ-irradiation dose was 2 kGy, compared with the untreated sample, the contents of cellulose, hemicellulose and lignin in pea fiber decreased by 1.34 ± 0.42%, 2.56 ± 0.03% and 2.02 ± 0.05%, respectively, and the volume particle size of pea fiber decreased by 17.43 ± 2.35 μm. The specific surface area increased by 23.70 ± 2.24 m2/kg and the crystallinity decreased by 7.65%. Pore and irregular particles appeared on the microstructure surface of the pea fiber treated with γ-irradiation. The results of the infrared spectrum showed that the hemicellulose and lignin in pea fiber were destroyed by γ-irradiation. These results indicate that γ-irradiation can significantly affect the structural properties of pea fiber. When the γ-irradiation dose was 2 kGy, the highest oil-holding capacity, swelling capacity and water-holding capacity of pea fiber were 8.12 ± 0.12 g/g, 19.75 ± 0.37 mL/g and 8.35 ± 0.18 g/g, respectively, and the adsorption capacities of sodium nitre, cholesterol and glucose were also the strongest. These results indicate that the functional properties of pea fiber are improved by γ-irradiation. In this study, γ-irradiation technology was used as pretreatment to provide a theoretical basis for the application of pea fiber in food processing.

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Native soy protein isolate (N-SPI) has a low denaturation point and low solubility, limiting its industrial application. The influence of different industrial modification methods (heat (H), alkaline (A), glycosylation (G), and oxidation (O)) on the structure of SPI, the properties of the gel, and the gel properties of soy protein isolate (SPI) in myofibril protein (MP) was evaluated. The study found that four industrial modifications did not influence the subunit composition of SPI. However, the four industrial modifications altered SPI’s secondary structure and disulfide bond conformation content. A-SPI exhibits the highest surface hydrophobicity and I850/830 ratio but the lowest thermal stability. G-SPI exhibits the highest disulfide bond content and the best gel properties. Compared with MP gel, the addition of H-SPI, A-SPI, G-SPI, and O-SPI components significantly improved the properties of the gel. Additionally, MP-ASPI gel exhibits the best properties and microstructure. Overall, the four industrial modification effects may impact SPI’s structure and gel properties in different ways. A-SPI could be a potential functionality-enhanced soy protein ingredient in comminuted meat products. The present study results will provide a theoretical basis for the industrialized production of SPI.

The effects of different structural parameters on the sealing performance of self-tightening metal U-shaped seal rings were studied. A two-dimensional axisymmetric model of a self-tightening U-shaped seal ring was established using finite element software. The influence of structural parameters such as side wall thickness, bottom wall thickness and boss radius on the sealing performance of the seal ring was analyzed by the control variable method. The results show that as the thickness of the side wall increases, the stress shows a downward parabolic trend, which is the smallest at 0.55 to 0.65 mm; as the bottom wall thickness increases, the stress first increases steadily, and then decreases slowly after 0.8 to 0.9 mm; When the inclination angle is from 0 to 9 °, the sealing ring can obtain better sealing performance. The results have guiding significance for the design, optimization and application of subsequent seal ring structures.