Protein Secondary Structure Research Articles

Effects of insoluble dietary fiber from mung bean skin on dough and gluten protein properties

Abstract In this study, the influences of the addition of different mung bean skin insoluble dietary fiber (MIDF) contents (0–10 wt%) on the properties of dough and gluten proteins were investigated. With the addition of MIDF, the elastic modulus, viscosity modulus, and loss factor of the dough all showed increasing trends. Additionally, the bound water content significantly increased by 15.37 % (P < 0.05), while the weakly bound water content decreased by 14.32 % (P < 0.05), indicating the migration of weakly bound water to bound water. These changes resulted in increased hardness, chewiness, and gumminess of the dough. Furthermore, the incorporation of MIDF significantly reduced the SS content in gluten by 43.01 % (P < 0.05). Concurrently, the secondary structure of gluten protein transformed from ordered structures, such as α-helices and β-sheets, to disordered structures, such as random coils and β-turns, thereby loosening the protein skeleton structure and affecting the gluten network. These results established a theoretical foundation for the development and enhancement of functional foods enriched with dietary fiber.

Insertion-deletions are depleted in protein regions with predicted secondary structure.

A fundamental goal in evolutionary biology and population genetics is to understand how selection shapes the fate of new mutations. Here we test the null hypothesis that insertion-deletion events (indels) in protein coding regions occur randomly with respect to secondary structures. We identified indels across 11,444 sequence alignments in mouse, rat, human, chimp, and dog genomes, then quantified their overlap with four different types of secondary structure - alpha helices, beta strands, protein bends, and protein turns - predicted by deep-learning methods of AlphaFold2. Indels overlapped secondary structures 54% as much as expected, and were especially under-represented over beta strands, which tend to form internal, stable regions of proteins. In contrast, indels were enriched by 155% over regions without any predicted secondary structures. These skews were stronger in the rodent lineages compared to the primate lineages, consistent with population genetic theory predicting that natural selection will be more efficient in species with larger effective population sizes. Nonsynonymous substitutions were also less common in regions of protein secondary structure, although not as strongly reduced as in indels. In a complementary analysis of thousands of human genomes, we showed that indels overlapping secondary structure segregated at significantly lower frequency than indels outside of secondary structure. Taken together, our study shows that indels are selected against if they overlap secondary structure, presumably because they disrupt the tertiary structure and function of a protein.

In vitro susceptibility of grass carp fish (Ctenopharyngodon idella) to oxidized myosin on structural change of protein secondary structure associated with reactive oxygen species (ROS) treatment

This study aimed to investigate the in vitro susceptibility of grass carp (Ctenopharyngodon idella) oxidized myosin, with the treatment of H2O2 levels being 0, 25, 50, and 100 μmol/L, respectively. The results showed that in vitro oxidation of myosin, reactive oxidative species promoted protein modifications that propagated the conformation changes on myosin secondary structure, leading to a significant increase (P < 0.05) in the protein carbonyl content in the high oxidation treatment, when compared to the low and medium treatments. The results of the Western blot analysis and sodium-polyacrylamide amide-dodecyl sulfate gel electrophoresis demonstrated that in vitro oxidation actively promoted the degradation of protein molecular weight and Desmin (53 kDa) deterioration in the sample with the highest concentration treatment of H2O2. Circular dichroism spectra showed a decrease in α-helix content from 70.1% to 29.8% and an increase in β-sheet percentage from 5.6% to 17.4%. Meanwhile, cysteine and methionine as the free amino acids were most susceptible to oxidative change due to their high sensitivity to the reaction of the sulfur group of amino acids. Protein degradation induced by oxidation resulted in significant changes to the protein secondary structure, as evidenced by the observation of oxidized myosin under different H2O2 levels.

Driving Role of Zinc Oxide Nanoparticles with Different Sizes and Hydrophobicity in Metabolic Response and Eco-Corona Formation in Sprouts (Vigna radiata).

Zinc oxide nanoparticles (ZnO NPs) cause biotoxicity and pose a potential ecological threat; however, their effects on plant metabolism and eco-corona evolution between NPs and organisms remain unclear. This study clarified the molecular mechanisms underlying physiological and metabolic responses induced by three different ZnO NPs with different sizes and hydrophobicity in sprouts (Vigna radiata) and explored the critical regulation of eco-corona formation in root-nano systems. Results indicated that smaller-sized ZnO inhibited root elongation by up to 37.14% and triggered oxidative burst and apoptosis. Metabolomics confirmed that physiological maintenance after n-ZnO exposure was mainly attributed to the effective stabilization of nitrogen fixation and defense systems by biotransformation of the flavonoid pathway. Larger-sized or hydrophobic group-modified ZnO exhibited low toxicity in sprouts, with 0.89-fold upregulation of citrate in central carbon metabolism. This contributed to providing energy for resistance to NP stress through amino acid and carbon/nitrogen metabolism, accompanied by changes in membrane properties. Notably, smaller-sized and hydrophobic NPs intensely stimulated the release of root metabolites, forming corona complexes with exudates. The hydrogen-bonded wrapping mechanism in protein secondary structure and hydrophobic interactions of heterogeneous functional groups drove eco-corona formation, along with the corona evolution intensity of n-ZnO > s-ZnO > b-ZnO based on higher (α-helix + 3-turn helix)/β-sheet ratios. This study provides crucial insight into metabolic and eco-corona evolution in bionano fates.

A new strategy to improve the quality of frozen chicken wings: High voltage electrostatic field combined with phosphorus-free water retaining agent

Freezing is a commonly used method for long-term storage of chicken wing products, of which disadvantages are mainly the product damage caused in the process. The aim of this study was to improve the freezing quality of chicken wings with a combination of phosphorus-free water retaining agent (WRA) and high-voltage electrostatic field (HVEF). The effect of WRA acting at different HVEF intensities (0, 1, 3, and 5 kV/cm) on the quality attributes of frozen chicken wings was investigated in 0, 7, 14, 21, 28 and 35 days of frozen storage. The results showed that WRA had functional properties of significantly improving the water holding capacity (WHC), color and texture properties, and fat stability of frozen chicken wing samples. The application of HVEF on this basis helped to promote the absorption of WRA and inhibit oxidative deterioration of chicken wing samples during frozen storage. Meanwhile, the combination of HVEF at 3 kV/cm was more prominent in terms of improvement in WHC, moisture content, color, protein secondary structure and microstructure integrity. This advantage had been consistently maintained with the extension of storage time. Overall, WRA combined with HVEF of 3 kV/cm can be used as an effective strategy to improve the freezing quality of chicken wing samples and has the potential to maintain the frozen chicken wing samples quality for a long time.

Stable Isotope Probing-nanoFTIR for Quantitation of Cellular Metabolism and Observation of Growth-Dependent Spectral Features.

This study utilizes nanoscale Fourier transform infrared spectroscopy (nanoFTIR) to perform stable isotope probing (SIP) on individual bacteria cells cultured in the presence of 13C-labelled glucose. SIP-nanoFTIR simultaneously quantifies single-cell metabolism through infrared spectroscopy and acquires cellular morphological information via atomic force microscopy. The redshift of the amide I peak corresponds to the isotopic enrichment of newly synthesized proteins. These observations of single-cell translational activity are comparable to those of conventional methods, examining bulk cell numbers. Observing cells cultured under conditions of limited carbon, SIP- nanoFTIR is used to identify environmentally-induced changes in metabolic heterogeneity and cellular morphology. Individuals outcompeting their neighboring cells will likely play a disproportionately large role in shaping population dynamics during adverse conditions or environmental fluctuations. Additionally, SIP-nanoFTIR enables the spectroscopic differentiation of specific cellular growth phases. During cellular replication, subcellular isotope distribution becomes more homogenous, which is reflected in the spectroscopic features dependent on the extent of 13C-13C mode coupling or to specific isotopic symmetries within protein secondary structures. As SIP-nanoFTIR captures single-cell metabolism, environmentally-induced cellular processes, and subcellular isotope localization, this technique offers widespread applications across a variety of disciplines including microbial ecology, biophysics, biopharmaceuticals, medicinal science, and cancer research.

Effects of electrohydrodynamics on drying characteristics and volatile profiles of goji berry (Lycium barbarum L.)

In this study, the changes in drying characteristics and volatile profiles of goji berries under different AC voltages (14, 18, 22, 26, and 30 kV) were investigated using an electrohydrodynamic (EHD) needle-plate electrode system. The results showed that increasing voltage significantly increased the drying rate, rehydration capacity, and lightness value of goji berry, decreased the drying time and browning degree (BI). The ordered structure in the secondary structure of goji berry proteins increased with increasing voltage. A total of 87 volatile compounds were identified in the dried goji berry under different drying voltages. Alcohols were the main volatile compounds. The short drying time can effectively reduce microbial contamination, resulting in the lowest content of alcohols in the dried goji berry products after drying at 30 kV. These findings reveal the drying characteristics and flavor formation mechanism of goji berries during electrohydrodynamic drying.

Cloning and Bioinformatics Analysis of FecB Gene in Improved Offspring of Suffolk Sheep

As is well known, the FecB (BMPR-IB) gene, as the earliest gene discovered by scientists that is closely related to sheep fertility, is the major gene responsible for multiple births in sheep. FecB gene shows a notable linkage with the quantity of newborn lambs. However, there has been limited research on the physicochemical properties and distribution of FecB in the improved descendants of Suffolk sheep. Therefore, this study first constructed a phylogenetic tree of the FecB (BMPR1B) protein in 30 species. The results showed that the improved descendants of Suffolk sheep are closely related to goats, water buffalo, domestic cattle, and humped cattle, indicating a strong level of conservation of BMPR-IB gene within the genus. At the same time, the physicochemical properties and structure of the FecB protein were analyzed, revealing that the FecB protein in the improved descendants of Suffolk sheep is positively charged, belongs to hydrophilic unstable alkaline proteins, contains a signal peptide, is a transmembrane protein, and has 56 phosphorylation sites. The secondary structure of the FecB protein consists of α-helices, extended chains, β-turns, and random coils, accounting for 34.86%, 13.15%, 3.39%, and 48.61%, respectively. Protein interaction analysis also showed that FecB has extensive regulatory interactions with members of the bone morphogenetic protein family. However, the examination of the BMPR-IB gene’s expression levels in nine tissues, which encompasses the heart, liver, spleen, and ovaries of the improved descendants of Suffolk sheep, showed the highest expression in the kidneys and the lowest expression in the spleen and small intestine. This study extensively explored the tissue expression profile and protein physicochemical structure of the BMPR-IB gene in the improved descendants of Suffolk sheep, aiming to lay a theoretical foundation for selecting high-yield improved descendants of Suffolk sheep.

Plasma activated water (PAW), Ozonated water (OW) and Slightly acidic electrolytic water (SAEW) treated tilapia fillets during chilled storage: A comparative study on quality changes and related mechanisms

Changes in protein degradation and lipid oxidation in tilapia fillets treated with plasma-activated water (PAW), ozonated water (OW), and slightly acidic electrolyzed water (SAEW) were investigated during refrigeration (12 d) at 4°C. Compared to the control group, PAW, OW, and SAEW effectively delayed the formation of trichloroacetic acid (TCA)-soluble peptides and free amino acids, and significantly reduced the drip loss rate by 1.52-3.60% after 12 d (P < 0.05). However, the total content of unsaturated fatty acids in all treatment groups decreased after 12 d. Compared to PAW and OW, SAEW better-maintained protein secondary and tertiary structure stability and preserved the most polyunsaturated fatty acids (27.32%). UHPLC-Q-TOF/MS analysis showed that accumulation of dipeptides/tripeptides (such as Trp-Trp-Pro, Tyr-Thr-Trp, Leu-Gln-Phe) enhanced the bioavailability and potential bioactivity of the proteins in all treatment groups. The 4-hydroxy-octanoic acid and 4-amino-pentanoic acid from fatty acid oxidation were significantly (P < 0.05) down-regulated in PAW and SAEW. Overall, PAW, OW, and SAEW may be feasible techniques for improving the quality of tilapia fillets during cold storage.

Probing Backbone Coupling within Hydrated Proteins with Two-Color 2D Infrared Spectroscopy.

The vibrational coupling between protein backbone modes and the role of water interactions are important topics in biomolecular spectroscopy. Our work reports the first study of the coupling between amide I and amide A modes within peptides and proteins with secondary structure and water contacts. We use two-color two-dimensional infrared (2D IR) spectroscopy and observe cross peaks between amide I and amide A modes. In experiments with peptides with different secondary structures and side chains, we observe that the spectra are sensitive to secondary structure. Water interactions affect the cross peaks, which may be useful as probes for the accessibility of protein sites to hydration water. Moving to two-color 2D IR spectra of proteins, the data demonstrate that the cross peaks integrate the sensitivities of both amide I and amide A spectra and that a two-color detection scheme may be a promising tool for probing secondary structures in proteins.

Regulating the bioactivity of non-glycosylated recombinant human bone morphogenetic protein-2 to enhance bone regeneration

Recombinant human bone morphogenetic protein-2 (rhBMP-2) is the predominant growth factor that effectively induces osteogenic differentiation in orthopedic procedures. However, the bioactivity and stability of rhBMP-2 are intrinsically associated with its sequence, structure, and storage conditions. In this study, we successfully determined the amino acid sequence and protein secondary structure model of non-glycosylated rhBMP-2 expressed by an E. coli expression system through X-ray crystal structure analysis. Furthermore, we observed that acidic storage conditions enhanced the proliferative and osteoinductive activity of rhBMP-2. Although the osteogenic activity of non-glycosylated rhBMP-2 is relatively weaker compared to glycosylated rhBMP-2; however, this discrepancy can be mitigated by incorporating exogenous chaperone molecules. Overall, such information is crucial for rationalizing the design of stabilization methods and enhancing the bioactivity of rhBMP-2, which may also be applicable to other growth factors.

Effect of prolonged cooking at low temperatures on the eating quality of Tibetan pork: meat quality, water distribution, and microstructure

Abstract Tibetan pigs inhabit the plateau regions and engage in extensive exercise. Their meat is firm and less palatable, and appropriate cooking conditions can improve the flavor of the meat. This study aimed to explore the impact of cooking temperatures and times on the cooking loss rate, moisture content, tenderness, and color of Tibetan pork to elucidate their effects on the eating quality of this meat. The results indicated a negative correlation between temperature and moisture content, which decreased from 72% to 65% as the temperature increased. Meanwhile, the oxidation of myofibrillar proteins substantially increased with cooking temperature and time, resulting in a gradual augmentation of the cooking loss and shear force of the pork. The migration of bound water and the release of free water from the pork were faster after treatment at 80 °C compared with 50 °C. The results of infrared spectroscopy suggested that prolonged cooking led to the conversion of α-helix into β-sheet in the secondary structure of myofibrillar proteins. The microstructures observed through scanning electron microscopy exhibited a gradual degradation of connective tissues in the muscles at high temperatures, and the fiber structure of the muscles became more condensed and granular, blurring the textural appearance of the muscles. These results indicated that prolonged cooking time at a low temperature (steaming for 6 h at 50°C ) was conducive to the optimal tenderness of Tibetan pork. This study provides a theoretical basis for improving the meat quality of Tibetan pork products and developing more rational processing methods.

Effect of partial substitution of complex phosphates with sodium bicarbonate on aggregation, conformation and gel properties of beef-pork-chicken complex myofibrillar proteins.

Complex phosphates (CP) can improve the physicochemical properties and gelation properties of myofibrillar fibrous protein (MP) in mixed meat products, but excessive intake of phosphates over a long period of time is harmful to health. This study investigated the effects of partial or complete substitution of CP with sodium bicarbonate (SB) on the physicochemical properties and gel properties of beef-pork-chicken mixed myofibrillar protein (BPC-MP), to evaluate the feasibility of this method in reducing the amount of phosphate in mixed meat products. Under the optimal substitution conditions, the turbidity of BPC-MP was reduced by 37.8%, the net negative potential was increased by 28.9%, and the modulus of elasticity (G') was increased. The tertiary structure indexes of protein (including fluorescence intensity, surface hydrophobicity and active thiol content) were significantly changed, while the α-helix and β-turn angle contents in the secondary structure of protein were significantly increased. In addition, the water retention ability and strength of gel were also improved, which were increased by 20.7% and 42.6%, respectively. The results of scanning electron microscopy (SEM) showed that the SB substitution group had a more compact and ordered microstructure. The results showed that partial substitution of CP with SB reduced the amount of phosphate added to BPC-MP and had a positive effect on the physicochemical and gel properties of BPC-MP. This article is protected by copyright. All rights reserved.

Effect of Ba2+ on the biomineralization of Ca2+ and Mg2+ ions induced by Bacillus licheniformis.

The effect of barium ions on the biomineralization of calcium and magnesium ions is often overlooked when utilizing microbial-induced carbonate precipitation technology for removing barium, calcium, and magnesium ions from oilfield wastewater. In this study, Bacillus licheniformis was used to bio-precipitate calcium, magnesium, and barium ions. The effects of barium ions on the physiological and biochemical characteristics of bacteria, as well as the components of extracellular polymers and mineral characteristics, were also studied in systems containing coexisting barium, calcium, and magnesium ions. The results show that the increasing concentrations of barium ions decreased pH, carbonic anhydrase activity, and concentrations of bicarbonate and carbonate ions, while it increased the contents of humic acids, proteins, polysaccharides, and DNA in extracellular polymers in the systems containing all three types of ions. With increasing concentrations of barium ions, the content of magnesium within magnesium-rich calcite and the size of minerals precipitated decreased, while the full width at half maximum of magnesium-rich calcite, the content of O-C=O and N-C=O, and the diversity of protein secondary structures in the minerals increased in systems containing all three coexisting ions. Barium ions does inhibit the precipitation of calcium and magnesium ions, but the immobilized bacteria can mitigate the inhibitory effect. The precipitation ratios of calcium, magnesium, and barium ions reached 81-94%, 68-82%, and 90-97%. This research provides insights into the formation of barium-enriched carbonate minerals and offers improvements for treating oilfield wastewater.

Effect of κ‐carrageenan on the physicochemical and structural characteristics of ready‐to‐eat Antarctic Krill surimi gel

SummaryThe impact of κ‐carrageenan on the physicochemical structural characteristics of ready‐to‐eat (RTE) Antarctic krill surimi gel (AKSG) was investigated. The modifications in chemical bonding, protein secondary structure, protein composition and microscopic morphology were compared in both gels with and without κ‐carrageenan. According to the findings, adding 4% (w/w) κ‐carrageenan could reduce the cooking loss of AKSG significantly (P &lt; 0.05), enhance the WHC and textural quality of AKSG and RTE AKSG and increase the amount of hydrophobic and disulfide bonds so that the secondary structure of Antarctic krill proteins could be shifted to the β‐sheet. However, there was little impact on the composition of the protein molecules according to the SDS‐PAGE. In addition, the usage of κ‐carrageenan significantly alleviated the disruption of the protein gel network caused by high‐temperature and high‐pressure treatments (P &lt; 0.05). Therefore, applying κ‐carrageenan could effectively enhance the gel quality of RTE AKSG.

Oxidation-flocculation conditioning to improve the performance and mechanism of municipal sludge dewatering

In this study, ferrous iron (Fe2+)-catalyzed sodium percarbonate (2Na2CO3·3H2O2) was used for conditioning (referred to as F-N conditioning) municipal sludge. On this basis, Fe2+-catalyzed 2Na2CO3·3H2O2 was coupled with polymerized ferrous sulfate (PFS) conditioning (referred to as F-N-P conditioning) as well as coupled with the compounding of PFS and cationic polyacrylamide (CPAM) conditioning were explored (referred to as F-N-P-C conditioning) for municipal sludge. The results showed that the optimal dosages of Fe2+, 2Na2CO3·3H2O2, PFS and CPAM were 15, 40, 200 and 0.3 mg/g of absolutely dry sludge (DS), respectively, in which the specific resistance of the sludge (SRF) and the water content of the filtered sludge cake (WC) dropped from 2.1 × 1013 m/kg and 90.5 % to 2.9 × 1011 m/kg and 75.3 %, respectively. The mechanism study showed that the hydroxyl radicals (•OH) generated by F-N-P-C effectively cleaved the extracellular polymer (EPS) and remodeled the protein secondary structure by affecting the ratio of α-sheet and β-helix in the proteins secondary structure. PFS and CPAM neutralized the negative charge on the surface of municipal sludge flocs, and adsorbed-bridged with sludge flocs to improve the settling performance of sludge. Finally, the results of the plate and frame filter press dewatering tests verified that the F-N-P-C conditioning mode was the best formulation of sludge conditioning and determined the optimal working conditions: sludge feeding time, pressing time and pressing pressure were 5400 s, 5400 s and 1.2 MPa, respectively. The chemical cost of F-N-P-C conditioning was preliminarily estimated as 58.55 USD$/ton DS. Therefore, The F-N-P-C process had certain practical value and promotion significance.

A Critical Review on Some Recent Developments in Comparison of Biological Sequences

The present review highlights some of the very important contributions to non-alignment ways of comparing biological sequences, which may be genome sequences of nucleotides, protein sequences of amino acids, or sequences of protein secondary structures. The discussion centers around specific methods applicable to the comparison of three types of sequences. The methods of comparison of genome sequences are based on three pairs of biological groups of nucleotides; the same for protein sequences are based on either physio-chemical property values of amino acids or on classified groups of amino acids of different cardinalities obtained from the physio-chemical properties; the same for sequences of secondary structures of proteins are based on their sequential expressions of structure elements of cardinality three and four. Comparison is made in the time domain and also in the frequency domain. Different taxa of known phylogeny are considered for comparison. It tries to find out the specific method of comparison, which can show the exact phylogeny of the taxa. If a new sequence appears in the database, it becomes essential to know its phylogeny. For this purpose, a phylogenetic tree is drawn on the sequences of the known taxa together with this new sequence using the best possible method. If the species having this new sequence belongs to the old taxa, there is nothing to worry about. Otherwise, the species with the new sequence has to be studied separately. This is the general reason for the construction of a phylogenetic tree in any form of biological sequence comparison.

Electronic Control of Polyproline II Helix Stability via the Identity of Acyl Capping Groups: the Pivaloyl Group Particularly Promotes PPII.

The type II polyproline helix (PPII) is a fundamental secondary structure of proteins. PPII is stabilized in part by n®p* interactions between consecutive carbonyls, via electron delocalization between an electron-donor carbonyl lone pair (n) and an electron-acceptor carbonyl (p*) on the subsequent residue. We previously demonstrated that changes to the electronic properties of the acyl donor can predictably modulate the strength of n®p* interactions, with data from model compounds, in solution in chloroform, in the solid state, and computationally. Herein, we examined whether the electronic properties of acyl capping groups could modulate the stability of PPII in peptides in water. In X-PPGY-NH2 peptides (X = 10 acyl capping groups), the effect of acyl group identity on PPII was quantified by circular dichroism and NMR spectroscopy. Electron-rich acyl groups promoted PPII relative to the standard acetyl (Ac-) group, with the pivaloyl and iso-butyryl groups most significantly increasing PPII. In contrast, acyl derivatives with electron-withdrawing substituents and the formyl group relatively disfavored PPII. Similar results, though lesser in magnitude, were also observed in X-APPGY-NH2 peptides, indicating that the capping group can impact PPII conformation at both proline and non-proline residues. The pivaloyl group was particularly favorable in promoting PPII.

Investigating the Interactions of the Cucumber Mosaic Virus 2b Protein with the Viral 1a Replicase Component and the Cellular RNA Silencing Factor Argonaute 1

The cucumber mosaic virus (CMV) 2b protein is a suppressor of plant defenses and a pathogenicity determinant. Amongst the 2b protein’s host targets is the RNA silencing factor Argonaute 1 (AGO1), which it binds to and inhibits. In Arabidopsis thaliana, if 2b-induced inhibition of AGO1 is too efficient, it induces reinforcement of antiviral silencing by AGO2 and triggers increased resistance against aphids, CMV’s insect vectors. These effects would be deleterious to CMV replication and transmission, respectively, but are moderated by the CMV 1a protein, which sequesters sufficient 2b protein molecules into P-bodies to prevent excessive inhibition of AGO1. Mutant 2b protein variants were generated, and red and green fluorescent protein fusions were used to investigate subcellular colocalization with AGO1 and the 1a protein. The effects of mutations on complex formation with the 1a protein and AGO1 were investigated using bimolecular fluorescence complementation and co-immunoprecipitation assays. Although we found that residues 56–60 influenced the 2b protein’s interactions with the 1a protein and AGO1, it appears unlikely that any single residue or sequence domain is solely responsible. In silico predictions of intrinsic disorder within the 2b protein secondary structure were supported by circular dichroism (CD) but not by nuclear magnetic resonance (NMR) spectroscopy. Intrinsic disorder provides a plausible model to explain the 2b protein’s ability to interact with AGO1, the 1a protein, and other factors. However, the reasons for the conflicting conclusions provided by CD and NMR must first be resolved.

Effects of ultrasound on the structural, physicochemical, and emulsifying properties of aquafaba extracted from various legumes

This study investigated the effect of ultrasound (20–60 min, 40 kHz, 280 W) on the structural, physicochemical, and emulsifying properties of aquafaba extracted from various legumes (chickpea [CH], yellow soybean [YSB], black soybean [BSB], small black bean [SBB]). The hydrophobic amino acids and protein secondary structures (α-helix, random coil) significantly increased with sonication time (p < 0.05). The particle size of aquafaba was reduced by ultrasound (p < 0.05). A total of 27 volatile compounds were identified. Most volatiles increased with sonication time, and beany flavor was lowest in CH and SBB. The EAI, ESI, adsorbed proteins, and zeta-potential increased, while emulsion droplet size decreased in all legumes by ultrasound. The overall emulsifying properties were the highest in SBB sonicated for 40 min. This study discusses the applicability of ultrasound to aquafaba and provides insights into the functional properties and potential of aquafaba as a plant-based natural emulsifier