Effects of atmospheric pressure plasma jet on the physicochemical, functional, and antioxidant properties of flaxseed protein

The casein in sheep milk processed by cold plasma technology: Phosphorylation degree, functional properties, oxidation characteristics, and structure

Cold plasma is a nonthermal process used for modification of proteins. The objective of this study was to investigate the effect of cold plasma technology on the phosphorylation degree, functional and oxidation properties, and structure of casein in sheep milk. Cold plasma treatment for 3-4 min significantly increased the phosphorylation degree and enhanced functional properties, including water-holding capacity, solubility, foaming capacity and stability. Besides, plasma treatment time profoundly influenced protein oxidation, and treatment for 2 and 3 min could be the preferred conditions to minimize protein change. The protein conformation became unstable with the extension of treatment time. Particle size, polymer dispersity index, and microscopy images confirmed alterations in the protein structure following 3 min of processing. Consequently, using cold plasma treatment at 10 kHz 20 kV for 3 min could be suggested for milk protein modification, providing a basis for the application of high-quality caseins in food processing.

A comprehensive review on the recent trends in extractions, pretreatments and modifications of plant-based proteins

Plant-based proteins offer sustainable and nutritious alternatives to animal proteins with their techno-functional attributes influencing product quality and designer food development. Due to the inherent complexities of plant proteins, proper extraction and modifications are vital for their effective utilization. This review highlights the emerging sources of plant-based proteins, and the recent statistics of the techniques employed for pretreatment, extraction, and modifications. The pretreatment, extraction and modification approach to modify plant proteins have been classified, addressed, and the recent applications of such methodologies are duly indicated. Furthermore, this study furnishes novel perspectives regarding the potential impacts of emerging technologies on the intricate dynamics of plant proteins. A thorough review of 100 articles (2018-2024) shows the researchers' keen interest in investigating novel plant proteins and how they can be used; seeds being the main source for protein extraction, followed by legumes. Use of by-products as a protein source is increasing rapidly, which is noteworthy. Protein studies still lack knowledge on protein fraction, antinutrients, and pretreatments. The use of physical methods and their combination with other techniques are increasing for effective and environmentally friendly extraction and modification of plant proteins. Several studies explore the effect of protein changes on their function and nutrition, especially with a goal of replacing ingredients with plant proteins that have improved or enhanced qualities. However, the next step is to investigate the sophisticated modification methods for deeper insights into food safety and toxicity.

Insights into Cold Plasma Treatment on the Cereal and Legume Proteins Modification: Principle, Mechanism, and Application

Cereal and legume proteins, pivotal for human health, significantly influence the quality and stability of processed foods. Despite their importance, the inherent limited functional properties of these natural proteins constrain their utility across various sectors, including the food, packaging, and pharmaceutical industries. Enhancing functional attributes of cereal and legume proteins through scientific and technological interventions is essential to broadening their application. Cold plasma (CP) technology, characterized by its non-toxic, non-thermal nature, presents numerous benefits such as low operational temperatures, lack of external chemical reagents, and cost-effectiveness. It holds the promise of improving proteins' functionality while maximally retaining their nutritional content. This review delves into the pros and cons of different cold plasma generation techniques, elucidates the underlying mechanisms of protein modification via CP, and thoroughly examines research on the application of cold plasma in augmenting the functional properties of proteins. The aim is to furnish theoretical foundations for leveraging CP technology in the modification of cereal and legume proteins, thereby enhancing their practical applicability in diverse industries.

Interactions between proteins and phenolics: effects of food processing on the content and digestibility of phenolic compounds

Phenolic compounds have recently become one of the most interesting topics in different research areas, especially in food science and nutrition due to their health-promoting effects. Phenolic compounds are found together with macronutrients and micronutrients in foods and within several food systems. The coexistence of phenolics and other food components can lead to their interaction resulting in complex formation. This review article aims to cover the effects of thermal and non-thermal processing techniques on the protein-phenolic interaction especially focusing on the content and digestibility of phenolics by discussing recently published research articles. It is clear that the processing conditions and individual properties of phenolics and proteins are the most effective factors in the final content and intestinal fates of phenolic compounds. Besides, thermal and non-thermal treatments, such as high-pressure processing, pulsed electric field, cold plasma, ultrasonication, and fermentation may induce alterations  in those interactions. Still, new investigations are required for different food processing treatments by using a wide range of food products to enlighten new functional and healthier food product design, to provide the optimized processing conditions of foods for obtaining better quality, higher nutritional properties, and health benefits. © 2024 Society of Chemical Industry.

Size-controllable food-grade nanoparticles based on sea cucumber polypeptide with good anti-oxidative capacity to prolong lifespan in tumor-bearing mice

Liver cancer, a malignancy with a rising global incidence, poses a significant challenge in achieving effective treatment outcomes. As food-derived nutrient, sea cucumber peptide (SCP) has shown promising anticancer effects. Therefore, we explored the nanodelivery systems to encapsulate SCP to enhance its stability in the gastrointestinal tract and improve absorption within the tumor microenvironment. This study aimed to develop size-controllable multifunctional nanoparticles using SCP, procyanidins (PCs), and vanillin through molecular assembly via a one-pot Mannich condensation approach. These food-grade nanoparticles demonstrated water solubility and exhibited a spherical structure with sizes ranging from 441 to 1360 nm, depending on the concentration of the reactants. In vitro cell experiments demonstrated that SCP nanoparticles modified with PCs effectively reduced the generation of reactive oxygen species from H2O2 and acrylamide while maintaining normal levels of mitochondrial membrane potential. Furthermore, in vivo nutrition intervention studies conducted on tumor-bearing mice revealed that mice treated with SCP nanoparticles exhibited a survival rate of 40 %, which was significantly higher than the 0 % and 20 % survival rates observed in the control and SCP-treated groups, respectively. These findings suggest that SCP nanoparticles, possessing antioxidative properties and controllable sizes, hold potential for precision nutrition in the field of cancer treatment.

Techno-functional attributes of oilseed proteins: influence of extraction and modification techniques

Plant-based protein isolates and concentrates are nowadays becoming popular due to their nutritional, functional as well as religious concerns. Among plant proteins, oilseeds, a vital source of valuable proteins, are continuously being explored for producing protein isolates/concentrates. This article delineates the overview of conventional as well as novel methods for the extraction of protein and their potential impact on its hydration, surface properties, and rheological characteristics. Moreover, proteins undergo several modifications using physical, chemical, and biological techniques to enhance their functionality by altering their microstructure and physical performance. The modified proteins hold a pronounced scope in novel food formulations. An overview of these protein modification approaches and their effects on the functional properties of proteins have also been presented in this review.

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

Chickpea protein (CPI) is a promising dietary protein and potential substitute for soy protein in food product development due to its high protein content and low allergenicity. However, CPI possesses denser tertiary and quaternary structures and contains certain amount of anti-nutritional factors, both of which constrain its functional properties and digestibility. The objective of this study was to assess the effectiveness of atmospheric pressure plasma jets (APPJ) as a non-thermal method for enhancing the functional characteristics and digestibility of CPI. In this study, the reactive oxygen and nitrogen species generated by the APPJ treatment led to protein oxidation and increased carbonyl and di-tyrosine contents. At the same time, the secondary, tertiary and microstructural structures of CPI were changed. The solubility, water holding capacity, fat absorption capacity, emulsifying capacity and foaming capacity of CPI were significantly improved after 30 s APPJ treatment, and a higher storage modulus in rheology was observed. Additionally, it was observed that the in vitro protein digestibility (IVPD) of APPJ-treated CPI increased significantly from 44.85 ± 0.6 % to 50.2 ± 0.59 % following in vitro simulated gastric and intestinal digestion, marking a noteworthy improvement of 11.93 %. These findings indicate that APPJ processing can enhance the functional and digestive properties of CPI through structural modification and expand its potential applications within the food industry.

Effect of atmospheric pin-to-plate cold plasma on oat protein: Structural, chemical, and foaming characteristics

The impact of novel pin-to-plate atmospheric cold plasma was investigated with input voltage (170 V, 230 V) and exposure time (15 & 30 min) on oat protein by studying structural (FTIR, circular dichroism (CD), UV-vis, Fluorescence), morphological (particle size analysis, SEM, turbidity), chemical (pH, redox potential (ORP), ζ potential, carbonyl, sulfhydryl, surface hydrophobicity), and foaming characteristics. The plasma treatment reduced the pH while increasing the ORP of the dispersions. These ionic environment changes affected the ζ potential and particle size leading to the formation of larger aggregates (170-15; 230-15) and distorted smaller ones (170-30; 230-30) as confirmed by SEM. The FTIR spectra showed reduced intensity at specific amide bands (1600-1700 cm^-1) and also an increase in carbonyl stretching (1743 cm^-1) representing oxidative carbonylation (increase in carbonyl content). Thus, the partial exposure of hydrophobic amino acids increases surface hydrophobicity. The altered secondary structure (rise in α-helix, decrement in β-sheets and turns), and tertiary structures were observed in circular dichroism (CD) and UV absorbance and fluorescence characteristics of proteins respectively. Furthermore, the increase in free sulfhydryl content and disulfide content was highly affected by the plasma treatments due to observed protein unfolding and aggregations. Besides, the increased solubility and reduced surface tension contributed to the improved foaming characteristics. Thus, plasma processing influences protein structure affecting their characteristics and other functionalities.

Protein Fractions from Flaxseed: The Effect of Subsequent Extractions on Composition and Antioxidant Capacity

Flaxseed proteins exhibit functionalities interesting for the food industry, including antioxidant capacity. Antioxidant activity depends on the protein composition and the presence of phenolic compounds extracted with them from the matrix. The research focused on the effect of subsequent protein extractions (water, salt and alkaline) of flaxseed meals (of three cultivars) on the protein fraction composition and its relations to antioxidant capacity. The protein and phenolic profiles and antioxidant functionalities (in antiradical ORAC and emulsion assays) were analysed. Spectroscopic characteristics of the fractions (fluorometric and FT-IR analysis) were also included. Our study has shown the effect of fractionation on the share of proteins at MW from 56-38 kDa (globulin-like) and <15 kDa (albumin-like) in the protein profiles. The highest globulin share was in the alkaline-extracted fractions (AEF) and albumin in the salt-extracted (SEF) ones. SDG (secoisolariciresinol diglucosides) and phenolic acids (p-coumaric and ferulic) were extracted with flaxseed proteins. Their contents were fraction-dependent and the highest in AEF. The concentration of phenolics in AEF corresponded with the highest antiradical capacity (ORAC) compared with the other fractions. However, the SEF showed a higher ability to inhibit oxidation in emulsions than AEF, which could be associated with the higher content of the low MW proteins.

An omics approach to delineating the molecular mechanisms that underlie the biological effects of physical plasma

The use of physical plasma to treat cancer is an emerging field, and interest in its applications in oncology is increasing rapidly. Physical plasma can be used directly by aiming the plasma jet onto cells or tissue, or indirectly, where a plasma-treated solution is applied. A key scientific question is the mechanism by which physical plasma achieves selective killing of cancer over normal cells. Many studies have focused on specific pathways and mechanisms, such as apoptosis and oxidative stress, and the role of redox biology. However, over the past two decades, there has been a rise in omics, the systematic analysis of entire collections of molecules in a biological entity, enabling the discovery of the so-called "unknown unknowns." For example, transcriptomics, epigenomics, proteomics, and metabolomics have helped to uncover molecular mechanisms behind the action of physical plasma, revealing critical pathways beyond those traditionally associated with cancer treatments. This review showcases a selection of omics and then summarizes the insights gained from these studies toward understanding the biological pathways and molecular mechanisms implicated in physical plasma treatment. Omics studies have revealed how reactive species generated by plasma treatment preferentially affect several critical cellular pathways in cancer cells, resulting in epigenetic, transcriptional, and post-translational changes that promote cell death. Finally, this review considers the outlook for omics in uncovering both synergies and antagonisms with other common cancer therapies, as well as in overcoming challenges in the clinical translation of physical plasma.

Comparative Composition Structure and Selected Techno-Functional Elucidation of Flaxseed Protein Fractions

This study aimed to comparatively elucidate the composition structure and techno-functionality of flaxseed protein isolate (FPI), globulin (FG), and albumin (FA) fractions. The results showed that FA possessed smaller particle dimensions and superior protein solubility compared to that of FG (p < 0.05) due to the lower molecular weight and hydrophobicity. FA and FG manifested lamellar structure and nearly spherical morphology, respectively, whereas FPI exhibited small lamellar strip structure packed by the blurring spheres. The Far-UV CD, FTIR spectrum, and intrinsic fluorescence confirmed more flexible conformation of FA than that of FG, followed by FPI. The preferential retention of free phenolic acids was observed for FA, leading to excellent antioxidant activities compared with that of FG in FPI (p < 0.05). FA contributed to the foaming properties of FPI, relying on the earlier interfacial adsorption and higher viscoelastic properties. FA displayed favorable emulsifying capacity but inferior stability due to the limited interfacial adsorption and deformation, as well as loose/porous interface. By comparison, an interlayer anchoring but no direct interface coating was observed for lipid droplets constructed by FG, thereby leading to preferable emulsion stability. However, FPI produced lipid droplets with dense interface owing to the effective migration of FA and FG from bulk phase, concomitant with the easy flocculation and coalescence. Thus, the techno-functionality of flaxseed protein could be tailed by modulating the retention of albumin fraction and specific phenolic acids.

Comparative structural and techno-functional elucidation of full-fat and defatted flaxseed extracts: implication of atmospheric pressure plasma jet

BACKGROUND

The relatively inferior techno-functionality of flaxseed protein/polysaccharide complexes, especially regarding emulsifying and antioxidant activities, has partially limited their implication in the health food system. The present study aimed to investigate the effects of an atmospheric pressure plasma jet (APPJ) on the physicochemical, structural and selected techno-functional properties of flaxseed extracts.

RESULTS

The results obtained showed that the full-fat and defatted flaxseed extract solutions (5 mg mL^-1 ) displayed a sustainable decline in pH (-54.06%, -48.80%, P < 0.05) and zeta potential values (-29.42%, -44.28%, P < 0.05), but a gradual increase in particle sizes, as visualised by an optical microscope, during 0-120 s of APPJ treatment. Moreover, the APPJ led to initial decrease but subsequent increase in protein carbonyls and secondary lipid oxidation products, and concurrently changed the spatial conformation and microstructure of flaxseed extracts, as indicated by endogenous fluorescence properties and scanning electron microscopy (SEM). Additionally, the protein subunit remodeling and gum polysaccharides depolymerization were different for full-fat and defatted flaxseed extracts after 30 s of APPJ exposure. Importantly, the emulsifying and antioxidant activities of defatted flaxseed extract were particularly improved, as assessed by cyro-SEM and 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity following 15-30 s of APPJ treatment, as a result of the changing interactions between protein and gum polysaccharides, as well as the release of specific phenolic compounds.

CONCLUSION

APPJ could serve as a promising strategy for tailoring the specific techno-functionality of flaxseed extracts based on mild structural modification. © 2021 Society of Chemical Industry.

Influences of microwave exposure to flaxseed on the physicochemical stability of oil bodies: Implication of interface remodeling

This study aimed to investigate the influences of microwave (MV) exposure to flaxseed on the physicochemical stability of oil bodies (OBs) focused on the interface remodeling. The results showed that the intracellular OBs subjected to absolute rupture and then partial dispersion by protein bodies visualized by TEM following MV exposure (1-5 min; 700 W). After aqueous extraction, native flax OBs manifested excellent spherical particles with completely intact surface and wide particle size distribution (0.5-3.0 μm) examined by cryo-SEM. Upon 1-5 min of MV exposure, the defective interface integrity and beaded morphology were successively observed for flax OBs, accompanied by the impaired physical stability and rheological behavior due to the newly assembled phospholipid/protein interface. Notably, the profitable migration of phenolic compounds effectively suppressed the lipid peroxidation and protein carbonylation in flax OBs. Thus, MV exposure (1-5 min; 700 W) was unfavorable for improving the physical stability of flax OBs.

Modifying the plant proteins techno-functionalities by novel physical processing technologies: a review

Plant proteins have recently gained market demand and momentum due to their environmentally friendly origins and health advantages over their animal-derived counterparts. However, their lower techno-functionalities, digestibility, bioactivities, and anti-nutritional compounds have limited their application in foods. Increased demand for physically modified proteins with better techno-functionalities resulted in the application of different thermal and non-thermal treatments to modify plant proteins. Novel physical processing technologies (NPPT) considered 'emerging high-potential treatments for tomorrow' are required to alter protein functionality, enhance bioactive peptide formations, reduce anti-nutritional, reduce loss of nutrients, prevention of damage to heat liable proteins and clean label. NPPT can be promising substitutes for the lower energy-efficient and aggressive thermal treatments in plant protein modification. These facts captivated the interest of the scientific community in designing novel functional food systems. However, these improvements are not verifiable for all the plant proteins and depend immensely on the protein type and concentration, other environmental parameters (pH, ionic strength, temperature, and co-solutes), and NPPT conditions. This review addresses the most promising approaches of NPPT for the modification of techno-functionalities of plant proteins. New insights elaborating the effect of NPPTs on proteins' structural and functional behavior in relation to other food components are discussed. The combined application of NPPTs in the field of plant-based bioactive functionalities is also explored.

The quality and antioxidant elucidation of germinated flaxseed treated with acidic electrolyzed water

The endogenous fortification of antioxidant lipid concomitants in flaxseed was imperative to improve the oxidative stability of α-linolenic acid (ALA) in flaxseed and flaxseed oil upon processing, storage and gastrointestinal digestion. The comparative effects of acidic electrolyzed water (ACEW) and tap water (TW) on the triglyceride configuration, typical lipid concomitants, and antioxidant properties of flaxseed were conducted during 0-5 days of germination. The results showed that ACEW enhanced the germination rate of flaxseed by 18.25% and simultaneously suppressed the dynamic depletion of ALA by 5.32% when compared with TW (p < .05). The total phenolic acids, lignans, and flavonoids were effectively accumulated in flaxseed following ACEW-mediated germination with the further increase by 4.82%, 15.48%, and 8.22% in comparison with those induced by TW (p < .05). The total contents of cyclolinopeptides in flaxseed progressively dropped following either ACEW or TW treatment, a slighter decrease by 5.59% for flaxseed treated by ACEW than that by TW. Notably, the maximum accumulation of tocopherols and phytosterols had been early obtained for flaxseed treated with ACEW for 2-3 days due to the de novo synthesis or intermolecular conformational transition (p < .05). Most importantly, ACEW-mediated germination led to higher increment of the thermal oxidative stability and antioxidant properties of flaxseed and flaxseed oil in comparison to TW. In brief, the initial oxidation temperature increased by 7.09% and 3.06% (p < .05), and the antioxidant activities as evaluated by DPPH, ABTS, and FRAP values raised by 3.86%-28.07% and 4.21%-9.18% (p < .05), respectively. These findings clarify that the germination especailly mediated by ACEW could be an effective method to further optimize the nutritional and functional properties of flaxseed through reconstructing the endogenous antioxidant system.

The Effect of Roasting on the Protein Profile and Antiradical Capacity of Flaxseed Meal

Roasting is more and more often used as a pre-treatment of flaxseeds. However, the process can influence flaxseed proteins that may be crucial for their properties. The aim of this research was to study changes in the electrophoretic protein profile (SDS-PAGE) and the antiradical capacity of flaxseed meals after roasting. The roasting temperature (160, 180, and 200 °C) and flaxseed cultivars (golden and brown seed) were factors including in the study. The free (F-MRP) and bound-to-protein (B-MRP) Maillard reaction products were also analyzed. The most significant changes in the SDS-PAGE protein profiles of roasted seeds of each of the tested flax cultivars were observed for the 13 kDa protein fraction (decrease) and for the 19 kDa and 17 kDa fractions (increase). The research revealed a significant correlation between the roasting temperature and B-MRP content, and changes in the percentage share of those three protein fractions. The antiradical capacity of roasted flaxseeds decreased, as compared with untreated seeds. After roasting at 200 °C the antiradical capacity of flaxseeds improved slightly, probably due to the MRP formation, but it was still significantly lower than that of the raw seeds. The research provides novel information about key protein fractions that seem to be important changing during heat treatment.