Influence of atmospheric pressure plasma jet on the structural, functional and digestive properties of chickpea protein isolate

Cold argon plasma-induced aggregated and non-aggregated structural changes in casein and peptidomic insights into allergenicity

Casein (CN) is a common allergen that is challenging to avoid in modern foods. The effect of cold argon plasma (CAP) on reducing CN antigenicity was investigated, focusing on alterations in epitope structure and sequence. CAP mainly contains hydroxyl radicals (∙OH). After a 12-min CAP treatment, the result of ELISA demonstrated an 80.46 % reduction in antigenicity. Transmission electron microscopy and electrophoresis revealed that certain CN aggregated, while multispectral analysis indicated that part of CN was fragmented into smaller peptides. The predictive 3D model suggested the disruption of linear epitopes located in the α-helix region might contribute to the reduced allergenicity. The peptide sequences were compared to the linear epitopes predicted by immunoinformatics approaches, revealing some reduction or breakage of key allergic sequences. Meanwhile, amino acids with aromatic side chains and hydrophobic groups were susceptible to CAP-induced modifications. This investigation demonstrated CAP could be beneficial for processing hypoallergenic foods.

Cold plasma reengineers peanut protein isolate: Unveiling changes in functionality, rheology, and structure

This study investigates the effects of cold plasma (CP) treatment on peanut protein isolate (PPI), focusing on functionality, rheology, and structural modifications across various treatment times (0, 90, 180, 270, 360, and 450 s) and voltages (120, 140, and 160 kV). Key findings include a significant increase in solubility from 9.99 mg/mL to 15.98 mg/mL, as well as 161.07 % enhanced water-holding capacity (WHC) and 448.45 % oil-holding capacity (OHC). CP treatment also improved foaming capacity (FC) to 186.46 % and increased emulsion capacity (EC) and emulsion stability (ES) by 185.90 % at 160 kV. Rheological analysis showed shear-thinning behaviour, with viscosity decreasing as the shear rate increased-higher voltages (140 kV and 160 kV) further reduced viscosity, indicating lower resistance to flow. Additionally, CP-treated PPI exhibited viscoelasticity, with increased storage and loss moduli at higher frequencies, indicating greater stiffness. Spectroscopic studies demonstrated shifts in the protein's secondary structure, altering the balance among alpha-helix, beta-sheet, and random coil components, which highlights CP's role in reengineering PPI. FTIR-ATR spectra revealed reductions in the 3200-3400 cm-1 range, suggesting changes in protein backbone vibrations and hydrogen bonding. Particle size analysis showed significant increases, especially at higher voltages and longer treatment times, stabilizing after 270 s. Zeta potential assays indicated a gradual decrease in negative surface charge, suggesting enhanced protein aggregation. Overall, CP treatment significantly improves the functional and rheological properties of PPI while inducing structural changes, making it more suitable for applications in the food and pharmaceutical industries.

Breaking barriers: Elevating legume protein functionality in food products through non-thermal technologies

Legume proteins have recently gained significant interest in the food industry for their eco-friendliness and nutritional qualities. Research shows that the replacement of specific animal protein sources with legume proteins presents sustainability and economic benefit. Nonetheless, legume proteins frequently exhibit inferior functional properties and palatability compared to animal proteins. Various non-thermal technologies, including high hydrostatic pressure, ultrasound, cold plasma, pulsed electric field, and dynamic high-pressure microjet, had been investigated to enhance the functional properties of legume proteins without loss of nutritional and sensory properties. Although these technologies show potential, no systematic study has been conducted to summarize and compare their effects on different legume proteins. This review aims to fill this gap by addressing the most promising approaches of non-thermal technologies for the modification of functional properties of legume proteins. New insights are discussed, elaborating the effect of non-thermal technologies on the structural and functional behavior of proteins.

Functionality enhancement of pea protein isolate through cold plasma modification for 3D printing application

Pea protein isolate (PPI) is a valued sustainable protein source, but its relatively poor functional properties limit its applications. This study reports on the effects of cold argon plasma (CP) treatment of a 15 % (w/w) PPI solution on the functionality, structure, and oxidative characteristics of PPI, as well as its application in 3D-printed plant-based meat. Results indicate that hydroxyl radicals and high-energy excited-state argon atoms are the primary active substances. A decrease in free sulfhydryl content and an increase in carbonyl content were observed in treated PPI, indicating oxidative modification. Compared to the control group, the gel strength of PPI was increased by 62.5 % and the storage modulus was significantly improved after 6 min treatment, forming a more ordered and highly cross-linked 3D gel network. Additionally, CP significantly improved the water-holding capacity, oil-holding capacity, emulsifying activity, and emulsion stability of PPI. The α-helix and random coil content in PPI decreased, while the β-sheet content increased, resulting in a more ordered secondary structure after CP treatment. Compared to untreated PPI, the consistency coefficient (K) increased from 36.00 to 47.68 Pa·sn. The treated PPI exhibited higher apparent viscosity and storage modulus and demonstrated better 3D printing performance and self-supporting ability. This study demonstrates that CP can significantly enhance the functional properties of PPI, providing great potential and prospects for improving the printability of 3D printing materials and developing plant protein foods with low-allergenicity.

Structural and gel property changes in chicken myofibrillar protein induced by argon cold plasma-activated water: With a molecular docking perspective

This study investigated the effects of plasma-activated water (PAW) generated with argon at discharge times of 0, 4, 8, 12, and 16 min on the gel properties and structures of chicken myofibrillar protein (MP). Under treatments of 8, 12, and 16 min, both the gel strength and water retention capacity of MP significantly improved, with the gel strength (0.53 N) peaking at 16 min and the lowest cooking loss（30.38 %）. As the treatment time increased from 0 to 16 min, the storage modulus also gradually increased. Results from low-field nuclear magnetic resonance indicated a slowing of water proton mobility, with the proportion of bound water rising from 0.26 % (0 min) to 0.52 % at 16 min. Fourier transform infrared spectroscopy, endogenous fluorescence spectroscopy and scanning electron microscopy confirmed PAW's alteration of MP's secondary and tertiary structures and gel microstructure. Additionally, this study explored the influence of argon PAW's primary active species on MP from a molecular docking perspective·H2O2 could form hydrogen bonds with MP, while O3 and NO2‾could interact via both hydrogen bonds and electrostatic interactions. Thus, PAW can alter protein structure and enhance MP's functional properties, providing insights for applying cold plasma in processing chicken gel products.

Freeze-thaw stability of high-internal-phase emulsion stabilized by chickpea protein microgel particles and its application in surimi

BACKGROUND

Future applications of high-internal-phase emulsions (HIPEs) are highly regarded, but poor freeze-thaw stability limits their utilization in frozen products. This study aimed to characterize the structure of chickpea protein microgel particles (HCPI) induced by NaCl and to assess its impact on the freeze-thaw stability of HIPEs.

RESULTS

The results showed that NaCl induction (0-400 mmol L-1) increased the surface hydrophobicity (175.9-278.9) and interfacial adsorbed protein content (84.9%-91.3%) of HCPI. HIPEs prepared with HCPI induced by high concentration of NaCl exhibited superior flocculation index and centrifugal stability, and their freeze-thaw stability was better than that of natural chickpea protein. The increase in NaCl concentration reduced the droplet aggregation and coalescence index of the freeze-thaw emulsions, diminishing the precipitation of oil from the emulsion. Linear and nonlinear rheology showed that the strengthened gel structure (higher G' values) restricted water flow and counteracted the damage to the interfacial film by ice crystals at 100-400 mmol L-1 NaCl, thus improving the viscoelasticity of the freeze-thaw emulsions. Finally, the thawing loss of surimi gel with HCPI-200 HIPE was reduced by 2.04% compared to directly adding oil.

CONCLUSION

This study provided a promising strategy to improve the freeze-thaw stability of HIPEs and reduce the thawing loss of frozen products. © 2024 Society of Chemical Industry.

Effect of exogenous selenium on physicochemical, structural, functional, thermal, and gel rheological properties of mung bean (Vigna radiate L.) protein

Selenium (Se) biofortification during the growth process of mung bean is an effective method to improve the Se content and quality. However, the effect of Se biofortification on the physicochemical properties of mung bean protein is unclear. The objective of this study was to clarify the changes in the composition, Se forms, particle structure, functional properties, thermal stability, and gel properties of mung bean protein at four Se application levels. The results showed that the Se content of mung bean protein increased in a dose-dependent manner, with 7.96-fold (P1) and 8.52-fold (P2) enhancement at the highest concentration. Exogenous Se application promotes the conversion of inorganic Se to organic Se. Among them, selenomethionine (SeMet) and methyl selenocysteine (MeSeCys) replaced Met and Cys through the S metabolic pathway and became the dominant organic Se forms in Se-enriched mung bean protein, accounting for more than 80 % of the total Se content. Exogenous Se at 30 g/hm2 significantly up-regulated protein content and promoted the synthesis of sulfur-containing protein components and hydrophobic amino acids in the presence of increased levels of SeMet and MeSeCys. Meanwhile, Cys and Met substitution altered the sulfhydryl groups (SH), β-sheets, and β-turns of protein. The particle size and microstructural characteristics depend on the protein itself and were not affected by exogenous Se. The Se-induced increase in the content of hydrophobic amino acids and β-sheets synergistically increases the thermal stability of the protein. Moderate Se application altered the functional properties of mung bean protein, which was mainly reflected in the significant increase in oil holding capacity (OHC) and foaming capacity (FC). In addition, the increase in SH and β-sheets induced by exogenous Se could alter the protein intermolecular network, contributing to the increase in storage modulus (G') and loss modulus (G″), which resulted in the formation of more highly elastic gels. This study further promotes the application of mung bean protein in the field of food processing and provides a theoretical basis for the extensive development of Se-enriched mung bean protein.

Study on the structural characteristics and emulsifying properties of chickpea protein isolate-citrus pectin conjugates prepared by Maillard reaction

Chickpea protein isolate (CPI) typically exhibits limited emulsifying properties under various food processing conditions, including pH variations, different salt concentrations, and elevated temperatures, which limits its applications in the food industry. In this study, CPI-citrus pectin (CP) conjugates were prepared through the Maillard reaction to investigate the influence of various CP concentrations on the structural and emulsifying properties of CPI. With the CPI/CP ratio of 1:2, the degree of graft reached 35.54 %, indicating the successful covalent binding between CPI and CP. FT-IR and intrinsic fluorescence spectroscopy analyses revealed alterations in the secondary and tertiary structures of CPI after glycosylation modification. The solubility of CPI increased from 81.39 % to 89.59 % after glycosylation. Moreover, freshly prepared CPI emulsions showed an increase in interfacial protein adsorption (70.33 % to 92.71 %), a reduction in particle size (5.33 μm to 1.49 μm), and a decrease in zeta-potential (-34.9 mV to -52.5 mV). Simultaneously, the long-term stability of the emulsions was assessed by employing a LUMiSizer stability analyzer. Furthermore, emulsions prepared with CPI:CP 1:2 exhibited excellent stability under various environmental stressors. In conclusion, the results of this study demonstrate that the glycosylation is a valuable approach to improve the emulsifying properties of CPI.