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The effect of soybean oil (SO) on freeze‐thaw (F‐T)‐treated surimi was investigated and its related mechanism was revealed by molecular dynamics (MD) simulations. The results displayed that SO has a disrupting effect on the structure of fresh samples. However, in the F‐T‐treated samples, surimi gels supplemented with SO had a more uniform microstructure. Simultaneously, when SO was added from 0% to 7% in the F‐T‐treated samples, the gel strength increased from 46.66to51.86N·mm (p <.05), the physically bound water was increased from 92.90% to 94.15% (p <.05), and storage modulus was increased from 5939 to 6523 Pa. Triglycerides of SO generated hydrophobic interactions with myosin mainly in carbon chains. Computational results from MD simulations illustrated that the structure of myosin combined with triglycerides was more stable than that of myosin alone during temperature fluctuations (−20 to 4°C). During ice crystal growth, triglycerides absorbed on the myosin surface inhibited the growth of surrounding ice crystals and mitigated the ice crystal growth rate (from 7.54 to 5.99 cm/s). The addition of SO during the F‐T treatments allowed myosin to be less negatively affected by ice crystal formation and temperature fluctuations and ultimately contributed to the formation of a more uniform network gel structure. [ABSTRACT FROM AUTHOR]

Currently, it is a challenge that the yolk in salted preserved egg tends to preserved egg yolk due to extreme NaOH treatment. Therefore, NaCl, NaOH and thermal were successfully used to prepare a new translucent salted quail egg (T-SQE), which combined advantages of preserved egg white with transparent appearance and salted egg yolk with unique texture and odour. Moreover, transparency of opaque gel (Transmittance: 0.09 %) subjected to NaCl and thermal was demonstrated to be improved under the synergistic effect of NaOH (8.55 %) via empirical data and molecular simulation. The disordered and dense network in opaque T-SQE induced by NaCl and thermal tended to form an ordered, porous and transparent structure in presence of NaOH, with more immobilized water that was poorly bonded to protein, larger radius of gyration and lower hydrophobic interaction. This research provides new insight into understanding the influence of hierarchy and synergism on transparency of egg products. [Display omitted] • A new T-SQE is obtained orderly and jointly driven by NaCl, NaOH and heat treatment. • Features of SEY and transparency of PEW are simultaneously acquired in the T-SQE. • Transparency of egg white thermogel induced by NaCl and NaOH is proved by test and MD. • Transparency of egg white thermogel induced by NaOH, NaCl depends on ordered α-helice. • Transparency of egg white gel ascribes to more macropore, big Rg, low hydrophobicity. [ABSTRACT FROM AUTHOR]

The effect of distribution behaviors of rice glutelin amyloid fibril aggregates (RAFA) on the structures and digestible process of wheat starch was investigated, and the interaction was revealed by molecular dynamics simulations. Rice glutelin (RG)/RAFA enhanced the long-range ordered structure of starch, and the relative crystallinity of gelatinized RAFA-wheat starch reached 14.35 %. Moreover, the RAFA was more effective than RG in improving the short-range ordered structure of starch. Simultaneously, the RAFA exhibited higher cross-linking with starch than the RG, forming continuous and compact network structures that encapsulated the starch. After 180 min of in vitro pancreatic digestion, the residual RAFA encapsulating the starch was still observed in the chyme, hindering amylolytic enzyme action and alleviating the starch digestibility. Molecular dynamics simulations further confirmed that the RAFA, compared to the RG, bound more readily to the starch molecule and formed more stable complexing structure. And the RAFA formed hydrogen bonds with the hydroxyl groups of starch through polar amino acid residues (Gln and Asn) and nonpolar residues (Ala, Gly, and Ile) with binding free energy of −263.868 kJ/mol, while that of the RG-starch was −28.798 kJ/mol. The study enriches the theory of regulating starch digestion using food-derived protein amyloid fibril aggregates. • RAFA enhanced both long-range and short-range ordered structures of wheat starch. • Continuous and compact networks of the RAFA facilitated encapsulation of the starch. • Residual protein fibrils helped to alleviate starch in vitro digestion further. • The RAFA interacted with hydroxyl groups of the starch through hydrogen bonding. [ABSTRACT FROM AUTHOR]

The aftertaste with a prolonged duration in ampelopsis grossedentata infusion (AGTI) is easily perceived, however, its formation mechanism is unclear. Therefore, aftertaste-A and richness were confirmed as the characteristic aftertaste of AGTI through sensory evaluation and electronic tongue. Moreover, 5-KETE, theobromine, etc., metabolites were identified as the differential components between AGTI and green tea infusion. Among them, p-coumaroyl quinic acid, xanthine etc., and proline, dihydromyricetin, etc., components contributed more to the formation of aftertaste-A and richness, respectively. Further, the bonding between characteristic metabolites for aftertaste in AGTI with their receptors were shown to be more stable using molecular docking, compared to metabolites related to typical taste profiles. The aftertaste in AGTI was more easily perceived by saltiness components or in NaCl system by molecular simulation. This study offers novel insight into the interaction mechanism of aftertaste in tea infusion and will contribute to further study on aftertaste for other foods. [Display omitted] • Aftertaste of astringency and umami, and saltiness are more easily perceived in AGTI. • Maltol, EGCG, aromadendrin, etc., components contribute to the aftertaste-A of AGTI. • Richness in AGTI attributes to proline, frutose, dihydromyricetin, etc., components. • Stronger interaction of aftertaste matrix- receptors in AGTI are validated by MD. • Interaction of aftertaste matrix and receptors are promoted by saltiness using MS. [ABSTRACT FROM AUTHOR]

[Display omitted] • Ultrafiltration fractions protected surimi gel from frozen deterioration. • The fractions displayed stabilizing mechanism on frozen surimi. • MD simulation visualized the binding sites between the fractions and myosin residues. • Hydrophilic and hydrophobic hotspot residues showed synergistic stabilizing action. This study investigated the cryoprotective mechanism of ultrafiltration membrane-separated fractions (>10 kDa, UF-1; 3–10 kDa, UF-2; and <3 kDa, UF-3) derived from silver carp hydrolysates on frozen surimi. The surimi gel incorporating UF-3 exhibited a compact, continuous structure with uniform pores, even after undergoing six freeze–thaw (F-T) cycle, with the minimal reduction in entrapped water (from 95.1 % to 91.1 %) and least increase in free water (from 4.5 % to 6.6 %) as revealed by SEM and LF-NMR analysis. Through molecular docking analysis, three major peptides in UF-3 were identified to form robust interactions with the myosin head pocket, facilitated by hydrogen bonds, electrostatic forces, and hydrophobic interactions. Furthermore, molecular dynamics simulations demonstrated that the three peptides effectively prevented myosin from unfolding and aggregating by tightly binding to basic amino acids (Arg, Lys) and hydrophobic amino acids (Phe, Leu, Ile, Met, and Val) residues in the myosin head pocket, primarily governed by electrostatic energies (−156.95, −321.38, and −267.53 kcal/mol, respectively) and van der Waals energies (−395.05, −347.46, and −319.16 kcal/mol, respectively). Notably, the key action site was identified as Lys599 on myosin. The hydrophilic and hydrophobic hotspot residues of the peptides worked synergistically to stabilize the myosin structure in frozen surimi. [ABSTRACT FROM AUTHOR]

In this study, intermolecular interactions and the self-assembly mechanism of rice glutelin amyloid fibril aggregates (RAFA) were studied using a combination of experimental and computer simulation methods. Based on the results of Thioflavin T fluorescence intensity, particle size measurement, and atomic force microscopy, the addition of NaCl and SDS accelerated the agglomeration of the RAFA, whereas adding urea caused the degradation of fibril clusters and the depolymerization of amyloid fibrils. The formation of the common cross β-sheet structure in the RAFA was primarily driven by hydrogen bonding, hydrophobic and electrostatic interaction were also involved. Visual molecular dynamics simulations indicated that randomly distributed peptides, hydrolyzed from rice glutelin, experienced aggregation, dispersion, structural rearrangements, and positional modifications to form the RAFA, which was compatible with the nucleation-elongation mechanism. The study supports for clarifying the self-assembly pattern of amyloid fibril aggregates derived from food protein, which is crucial for the denovo design and practical application of protein-amyloid fibril aggregates. [Display omitted] • Self-assembly pattern of food-derived protein firstly revealed by MD simulations. • Formation of transient states during self-assembly of RAFA were observed. • The intermolecular interactions of RAFA were elucidated at the molecular level. • The study provided new insights into denovo design of amyloid fibril aggregates. [ABSTRACT FROM AUTHOR]

• Ultrafiltration can be used to produce surimi cryoprotectants on a large scale. • The separated fractions abode by the antifreeze mechanism of adsorption-inhibition. • Molecular dynamics simulation visualized the inhibition effect on ice crystals. • Hydrophilic and hydrophobic amino acid residues offered synergistic effects. The membrane-separated silver carp hydrolysates (>10 k D , 3–10 k D and < 3 k D) displayed abilities to mitigate oxidation and denaturation of myofibrillar protein and cryoprotective activities for frozen surimi. However, the mechanism of the membrane-separated fractions on ice crystal growth in the system is still unknown. Therefore, the cryoprotective activities (recrystallization inhibition, RI and thermal hysteresis activity, THA) of the fractions were investigated and the mechanism was explored by molecular dynamics (MD) simulation to predict the probable binding sites and model the possible interactions between the peptides and water/ice. The fractions < 3 k D displayed remarkable RI activity, with significantly higher THA (0.60 ± 0.13 °C) and lower amount of ice nuclei (4.74 ± 0.53%) than that of fractions > 10 k D and 3–10 k D. The results of MD simulation certified that the main peptides in the fractions < 3 k D interacted firmly with water molecules and inhibited growth of ice crystals with mechanism compatible with Kelvin effect. Hydrophilic and hydrophobic amino acid residues in the membrane-separated fractions offered synergistic effects on the inhibition of ice crystals. [ABSTRACT FROM AUTHOR]

• A novel antifreeze peptide (AFP) was obtained from silver carp muscle hydrolysate. • The novel AFP (Sc-AFP) was derived from the parvalbumin. • Sc-AFP could bind to 48 water molecules and ice surface via hydrogen bonds. • An FNHK loop of Sc-AFP was a specific binding site for inhibiting ice growth. This study aimed to screen and characterize antifreeze peptides from silver carp muscle hydrolysate (SCMH). The SCMH was initially fractionated by ultrafiltration, and the resultant SCMH-IV (<10 kDa) showing 90 % of yeast survival rate was subsequently separated into four fractions using ion-exchange chromatography. The fraction with the best antifreeze activity was further analyzed by liquid chromatography-tandem mass spectrometry. A total of 514 peptides were identified, of which a novel antifreeze peptide (Sc-AFP, KAADSFNHKAFFAKVG) with a thermal hysteresis activity of 0.87 ℃ was selected. The parvalbumin-derived Sc-AFP showed an alanine-rich, α-helical and amphipathic character. Based on molecular dynamics simulations, the Sc-AFP could interact with 48 water molecules via hydrogen bonds, and could be adsorbed onto the ice surface through a total of 21 hydrogen bonds mainly linked to the lysine residues. This could account for its antifreeze properties via preventing the formation and growth of ice crystals. [ABSTRACT FROM AUTHOR]