The inherent characteristics of pectin often lead to insufficient adaptability. In the study, apple pectin was treated under ultra-high pressure to optimize its properties. The results demonstrated that ultra-high pressure treatment at 100-700 MPa for 15 min significantly improved the physicochemical and functional properties. Specifically, it significantly increased the degree of esterification, emulsifying activity and stability, water- and oil-holding capacities, and swelling power, while also enhancing fat/glucose adsorption and α-amylase inhibition. Treatment at 400-500 MPa for 15 min was identified as maximizing in enhancing these properties. Microstructural analysis revealed that ultra-high pressure disrupted and loosened the pectin matrix, which was closely correlated with the enhanced functionalities. These findings demonstrated that moderate ultra-high pressure treatment effectively improved pectin properties by altering its structure. It provides a theoretical basis for the application of ultra-high pressure modified pectin as the functional foods.

Fusarium head blight (FHB) caused by Fusarium graminearum leads to huge yield losses and mycotoxin contamination in wheat globally. Paenibacillus polymyxa with strong antagonistic activity was preliminarily identified. To clarify the key antifungal component, an extracellular protein was purified via ammonium sulfate precipitation, DEAE-52 anion-exchange and Sephadex G-75 gel filtration chromatography. SDS-PAGE showed a single band at 76 kDa. liquid chromatography–tandem mass spectrometry (LC-MS/MS) analysis confirmed this protein belongs to glycosyl hydrolase family with 86% sequence coverage. Biochemical characterization showed that the crude protein was stable at 40–90 °C and pH 3.0–9.0, sensitive to proteinase K, trypsin and neutral protease. The purified 76 kDa protein exhibited antifungal activity against F. graminearum. The gene encoding this protein was cloned and expressed in Escherichia coli. The renatured recombinant protein p76kd showed comparable antifungal activity to the native protein. This study purified and characterized a 76 kDa protein annotated as a glycosyl hydrolase via LC-MS/MS peptide matching; its antifungal function is presumed to originate from the conserved glycosyl hydrolase domain according to existing homologous research, which is distinct from previously reported lipopeptides or uncharacterized complexes. This protein provides a promising candidate for the biocontrol of FHB and related fungal diseases in cereal crops.

This study systematically investigated the synergistic effects of co-fermentation with Lactobacillus plantarum and Streptococcus thermophilus combined with sourdough (LSD) on dough functionality, contrasting it with sourdough-only fermentation (SD) and unfermented dough. LSD significantly enhanced dough elasticity (G') while reducing viscosity (G'') versus SD. LSD enhanced gluten network stability with an 86.73% rise in hydrogen bonds and reductions in ionic (−60.00%) and hydrophobic interactions (−26.17%) relative to unfermented dough. Degradation of high-MW glutenins reduced the gluten index to 56.64% (vs. SD 62.71%). Starch analysis showed LSD reduced amylose content by 9.71% and significantly lowered retrogradation enthalpy and setback viscosity versus SD (p < 0.05). FTIR confirmed enhanced starch molecular order (1047/1022 cm⁻¹ ratio). LAB-driven acidification and enzymatic activity optimized protein crosslinking and starch retrogradation resistance. This co-fermentation strategy improves dough extensibility, gas retention, and shelf-life stability, supporting probiotic steamed bread production.

This research investigated how alkaline pH shifting (pH 9-12) affects the structural characteristics and fermentation-induced gelation of pea protein (PP) as well as PP/casein (CS) binary systems. The results showed that as pH increased from 9 to 12, the solubility of PP and PP/CS significantly increased by 37.04%-51.09%. Meanwhile, particle size initially decreased by 12.02%-32.32% as pH increased to 10, but subsequently increased at pH 11 and 12, accompanied by reduced homogeneity. This phenomenon could be attributed to the dissociation of legumin 11S and the formation of large protein aggregates. Secondary structure analysis further indicated that alkaline pH shifting treatment increased the proportion of random coils (5.90%-28.39%) and beta-turns (18.47-49.67%). Regarding the gel properties induced by fermentation, moderate pH 10 treatment generated compact and ordered microstructures and superior elasticity in PP and PP/CS gels, as evidenced by enhanced hardness and water-holding capacity. In contrast, excessive alkaline treatment at pH 12 resulted in deteriorated gel performance and weakened structural integrity. This structural enhancement of PP and PP/CS gels triggered by pH 10 alkaline shifting was primarily attributed to strengthened hydrophobic interactions and hydrogen bonding.

To address the poor barrier performance of ginger starch films, this study used alkali-modified citrus fiber to develop a biodegradable composite film with enhanced functional properties. Alkali treatment (pH 8.5-11.5) restructured the fiber by removing amorphous pectin (decreasing from 20.46% to 8.54%) and enriching cellulose content (increasing from 22.34% to 38.09%). These compositional shifts promoted intermolecular hydrogen bonding and enhanced crystallinity, thereby improving the fiber's compatibility with the starch matrix and increasing the resulting film's compactness. Structural characterization via Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), low-field nuclear magnetic resonance (LF-NMR), and scanning electron microscopy (SEM) confirmed these modifications. Molecular docking and quantum chemical calculations further elucidated that hesperidin and cellulose of citrus fiber interacted strongly with starch via hydrogen bonds (binding energies from -5.490 to -8.116 kcal/mol) and van der Waals forces, thus promoting the formation of a denser film network. The optimized composite film exhibited superior water vapor barrier (WVP: 1.19 & times; 10- 10 g m- 1 & sdot;s- 1 & sdot;Pa- 1), mechanical strength (11.44 MPa), and UV blocking (92.04%). Applied to cherry preservation, the film significantly reduced spoilage by maintaining higher phenolic content and titratable acidity. This work provides a molecular-level understanding of fiber-starch interactions for developing high-performance biodegradable packaging.

Dried distillers grains are rich in dietary fiber and protein. Dried distillers grains was added to wheat flour to improve the nutrition and sensory quality of wheat flour staple food. The effects of Dried distillers grains on the thermomechanical properties and rheological properties of wheat flour dough were studied. After the addition of Dried distillers grains, the water absorption and protein weakening degree of the dough increased significantly. Simultaneously, the stability time and formation time decreased significantly. These changes indicate that Dried distillers grains has a substantial influence on the network structure of protein in wheat flour dough and on the gluten strength of the dough. Interestingly, the increase in the elastic modulus (G ') and viscous modulus (G '') indicates enhanced stability in the dough structure, resulting in reduced fluidity and viscosity. Texture analysis revealed that Dried distillers grains could significantly reduce bread hardness within the 2-8 % range, while also increasing the specific volume of the bread. The sensory score reached its highest point with an 8 % substitution of Dried distillers grains. These results demonstrate that the addition of 2-8 % Dried distillers grains improves the quality of the bread.

This study aimed to investigate the impact of introducing varying percentages (10-50 %) of milk protein concentrate (MPC) on the physicochemical characteristics and in vitro digestibility of fermentation-induced mung bean protein (MBP) gels. The results indicated that the storage modulus (G'), hardness, and chewiness of the MBP/MPC hybrid yogurt gel initially increased and then reduced with rising MPC levels. The MBP/MPC gel with a composition of 30 % MPC and 70 % MBP exhibited the highest G' and water-holding capacity (WHC) as well as the most uniform and dense network structure. This enhancement is primarily attributed to the MPC promoting hydrophobic interactions and hydrogen bonding among protein molecules. In contrast, when the MPC substitution exceeded 40 %, the gel quality deteriorated, characterized by delayed gel acidification, reduced storage modulus (G'), decreased WHC, and a looser network structure. Furthermore, MBP/MPC gel exhibited higher soluble protein content and peptide content compared to MBP gel. The gastrointestinal digestibility of MBP/MPC gel was higher than MBP gel. These findings would serve as a theoretical reference for the application of MBP and MPC in the development of hybrid protein gel-based yogurt.

Apple (Malus domestica) polyphenols possess functional properties; however, their human body absorption is impeded. To enhance their absorption, apple polyphenols were fermented using Lacticaseibacillus rhamnosus zrx01. Gastrointestinal digestion and metabolomics analyses were conducted. The results showed that the polyphenol content decreased significantly to 1.12 mg/mL (p < 0.05) in fermentation group and increased to 2.01 mg/mL in non-fermentation group; 6 differential metabolites such as ferulic acid (log₂ FC = -3.28) and p-hydroxybenzoic acid (log2 FC = -2.80) were identified by metabolomics, among which epicatechin (VIP = 2.54) and chlorogenic acid (VIP = 2.40) were significantly increased. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway analysis showed that differential metabolites were significantly enriched in 10 metabolic pathways, including phosphatidylinositol 3 kinase-protein kinase signaling pathway (p = 0.00029), fluid shear stress, and atherosclerosis pathway (p = 0.00327). The research shows fermentation converts macromolecular polyphenols into small molecules via deglycosylation, altering postdigestive metabolite profiles and providing evidence for bioavailability mechanisms and functional development of apple polyphenols.

Bacterial keratitis is one of the most common causes of visual impairment and blindness worldwide, and suffers the risk of drug-resistant infections due to the abuse of antibiotics. Despite its ability to counteract antibiotic resistance by inducing ferroptosis, the application of Fe2+ is limited by oxidative instability and a solution pH often incompatible with ophthalmic use. Thus, this study designed and synthesized an ascorbate-ferrous iron complex (SA-Fe(II)) using ferrous lactate and sodium ascorbate, followed by comprehensive structural characterization. Results confirmed the formation of coordination bonds between Fe2+ and sodium ascorbate. The molecular ion peak and characteristic decarboxylated fragment, along with broad and diffuse diffraction peaks in X-ray diffraction patterns, verified the formation of an amorphous metal chelate structure stabilized by dynamic coordination bonds. The SA-Fe(II) complex exhibited potent antibacterial activity, achieving more than 99.99 % killing of Staphylococcus aureus (S. aureus) and methicillin-resistant Staphylococcus aureus (MRSA) at 100 μM within 3 h. When incorporated into a sodium hyaluronate eye-drop matrix (SA-Fe(II)-SH), the formulation exhibited excellent ocular biocompatibility, as evidenced by hemolysis rates less than 5 %, more than 95 % viability of human corneal epithelial cells (HCE-T) corneal epithelial cells over 3 days, and no observable tissue inflammation in vivo. Importantly, in a mice model of MRSA keratitis, SA-Fe(II)-SH significantly reduced bacterial load, suppressed the production of inflammatory cytokines (IL-1β, IL-6, TNF-α), promoted corneal repair, and prevented systemic dissemination. This non-antibiotic strategy integrates antibacterial, anti-inflammatory, and pro-healing functions, offering a safe and effective therapeutic approach for the treatment of drug-resistant bacterial keratitis.

This study aimed to explore the impact of ultrasound-assisted pH-shifting on the physicochemical characteristics of a mung bean protein/milk protein concentrate (MBP/MPC) hybrid protein system and assess its applicability in hybrid yogurt gels. The results indicated that ultrasound and pH-shifting synergistically improved the physicochemical properties of hybrid protein system, increasing solubility (86.92 %-91.98 %), enhancing emulsification (4.08 %-53.65 %), and reducing particle size (8.02 %-87.87 %). Additionally, ultrasound-assisted pH-shifting significantly decreased α-helix and β-turn contents while increasing random coils content, without altering the protein's primary structure. In hybrid yogurt gel applications, ultrasound-assisted pH-shifting markedly improved gel texture, water-holding capacity, and elasticity. However, when the MBP/MPC ratio exceeded 60:40, the hybrid gels exhibited inferior properties compared to mung bean protein single yogurt gels, even after treatment. The best gel quality was attained at an 80:20 MBP/MPC ratio, where hydrophobic interactions were identified as the dominant factor in gel network formation. These findings suggested that the quality of hybrid protein yogurt gels strongly depends on the MBP/MPC mixing ratio. This study provides a theoretical basis for applying ultrasound-assisted pH-shifting in MBP/MPC hybrid protein yogurt gel systems.

Alicyclobacillus acidoterrestris causes pasteurized acidic juices spoilage, resulting in a significant decline in juice quality and causing economic losses. Exploration of A. acidoterrestris in response to acid stress could help control contamination caused by the bacteria. In this study, the mechanism of A. acidoterrestris in response to acid stress was studied by quantitative phosphoproteomics technique. Results showed that the phosphorylation of 40 proteins in A. acidoterrestris was closely related to the regulation of acid stress. The KEGG pathway enrichment analysis showed that the quorum sensing pathway, which might be involved in the perception of A. acidoterrestris, was mainly enriched. We found that the upregulation of Spo0A and YidC phosphorylationmay resist acid stress by forming spores. The phosphorylation level of pyruvate kinase increased, which may improve bacterial acid stress resistance through the formation of energy supply. The phosphorylation level of ABC transporter permease was significantly upregulated, which may be part of the cell adaptation adjustment and contribute to the survival of A. acidoterrestris under acid stress. In summary, the molecular mechanism of acid stress regulation of A. acidoterrestris was proposed via quantitative phosphoproteomics, which provided a theoretical and experimental basis for further investigation of the acid resistance mechanism of A. acidoterrestris. KEY POINTS: • Spo0 A, Yidc proteins may be the key regulatory proteins for acid stress response. • ABC transporters are beneficial to the survival of the bacteria under acidic stress. • A. acidoterrestris may sense and transmit pH signal through quorum sensing pathway.

The emergence of multidrug-resistant bacteria, particularly methicillin-resistant Staphylococcus aureus (MRSA), poses a significant threat to public health, necessitating new antimicrobial strategies. Here, we demonstrate that low doses of copper sulfate (CuSO4) exhibit potent bactericidal effects against both S. aureus and MRSA by inducing ferroptosis. CuSO4 treatment causes bacterial cell membrane perforation, increases intracellular free copper (Cu+) and ferrous ions (Fe2+), elevates reactive oxygen species (ROS) production and lipid peroxidation, and triggers the intracellular Fenton reaction. The use of ROS scavengers, copper chelators, iron chelators, and iron oxidase inhibitors attenuated ROS levels and lipid peroxidation, reducing Cu2+-mediated cell death, confirming the role of ferroptosis. Proteomic analysis revealed that Cu2+ enhances the expression of Fur protein, mediates iron release from intracellular stores, and inhibits glutathione biosynthesis. Furthermore, we developed a sodium alginate hydrogel loaded with CuSO4 (Cu-SA), which significantly improved wound healing and reduced inflammation and organ damage in an MRSA-infected mouse skin model. Our findings suggest that Cu2+-induced ferroptosis offers a promising alternative to traditional antibiotics for treating MRSA infections, providing a novel strategy to combat antibiotic resistance in S. aureus.

This study investigated the bioactive substance contents within extracts derived from different parts of Lonicera japonica Thunb.and assessed their bacterial inhibitory activities against 12 test strains.Initially,the concentrations of total phenols,total flavonoids,and chlorogenic acid were determined in Lonicera japonica leaves,Lonicerae japonica Flos,and Lonicera japonica caulis.Subsequently,the bacterial inhibition profiles of their extracts against 12 test strains were analyzed.Building upon this analysis,the effects of Lonicerae japonica Flos and Lonicera japonica leaves extracts on minimum inhibitory concentration(MIC),minimum bactericidal concentration(MBC),growth curve,biofilm formation,and cell morphology of Alicyclobacillus acidoterrestris were further investigated.Results revealed that the concentrations of total phenols,total flavonoids,and chlorogenic acid in L.japonica leaves and L.japonica Flos were significantly higher than those from L.japonica caulis(P-＜0.05).Moreover,the total flavonoids content in L.japonica leaves was notably higher than that in L.japonica Flos(P＜0.05).Three extracts exhibited varying degrees of bacteriostatic effects against A.acidoterrestris,Staphylococcus aureus,Streptococcus agalactiae,Listeria monocytogenes,Bacillus subtilis,Escherichia coli and Salmonella.Notably,extracts of L.japonica leaves and L.japonica Flos displayed superior bacteriostatic effects compared to L.japonica caulis.Extracts of L.japonica leaves and L.japonica Flos exhibited the most significant bacteriostatic effects against A.acidoterrestris,with MIC of 3.91 mg/mL and MBC of 31.25 mg/mL.Furthermore,extracts from L.japonica leaves and L.japonica Flos effectively inhibited the growth and biofilm formation of A.acidoterrestris,causing disruptions to their organism morphology.Notably,the inhibitory effects were augmented with the increase of extract concentrations.This study lays a robust foundation for understanding the mechanisms behind L.japonica inhibition of A.acidoterrestris and offers insights for developing safe and efficient new food bacteriostatic agents.

Inosine could potentially become a novel antibacterial agent against Alicyclobacillus acidoterrestris as low doses of inosine can prevent its contamination. However, until now the antibacterial mechanism of inosine targeting A. acidoterrestris is still unknown. In this study, to unravel the mechanism of inosine against A. acidoterrestris puzzle, the effects of inosine on bacterial surface hydrophobicity, intracellular protein content, cell membrane damage extent, and permeability of the A. acidoterrestris were investigated. The results showed that inosine can effectively inhibit the growth and reproduction of A. acidoterrestris by destroying the integrity of cell membrane and increasing its permeability, causing the leakage of intracellular nutrients. Furthermore, the interaction networks of inosine target proteins were analyzed. The interaction networks further revealed that damage to bacterial cell membranes might be relevant to inosine's effect on bacterial DNA replication and cell energy metabolism through regulating nucleotide synthesis and metabolism and the activity of translation initiation factors. Finally, the antibacterial mechanism of inosine against A. acidoterrestris was proposed.

The study aimed to evaluate the gel properties of mung bean protein (MP)/sodium caseinate (NaCas) hybrid yogurt at various mixing ratios, such as rheology, texture, water holding capacity, microstructure, and formation mechanism. The gel hardness, storage modulus (G') and water holding capacity of MP/NaCas yogurt increased and subsequently decreased as the NaCas level increased, maximum at a MP/NaCas ratio of 70:30. Meanwhile, as the MP/NaCas ratio was 70:30, the hybrid yogurt gel formed tighter and finer network structure. Moreover, the MP/NaCas hybrid yogurt slowed down the acidification rate with increasing NaCas ratio. Especially when NaCas was added at 50 %, the blend sample presented the longest fermentation time (280 min). Results showed that the optimal physicochemical characteristics of the yogurt gel were obtained when MP/NaCas ratio was mixed at 70:30. The results of the intermolecular forces indicated that hydrophobic interactions were the main factor causing yogurt gel formation.

Alicyclobacillus acidoterrestris (A. acidoterrestris) causes the spoilage of pasteurized acidic fruit juice due to its unique thermoacidophilic properties, which caused economic losses to fruit juice industry. To reveal the molecular regulatory mechanism of how A. acidoterrestris responded to acid stress is the key to hazard control of this microbe. Herein, acid-responsive proteome expression profiles of A. acidoterrestris were analyzed using label-free quantitative mass spectrometry to investigate its acid resistance mechanism at sublethal pH. Totally, 325 differential expression proteins were identified during acid stress (pH 2.5, 15 min duration), of which the expressions of 83 proteins were up-regulated and the other 242 protein expressions were down-regulated. The identified differentially expressed proteins were mainly involved in small molecule metabolism, organic nitrogen compounds metabolism, organic acid metabolism, and signal transduction. Overall, they were mapped into 97 metabolic pathways. Combination of KEGG pathway analysis and protein functional analysis suggested that the pH homeostasis system variation and relevant changes in metabolic pathways, cell membrane permeability and DNA repair are the main acid resistance mechanisms of A. acidoterrestris. Our finding implied that A. acidoterrestris might sense and transmit pH signals from the external environment through NhaB protein which holds histidine-dependent acid resistance system, initiating a series of acid tolerance reactions. Taken together, our study demonstrated global physiological response of A. acidoterrestris to sublethal pH, which provided a better understanding of acid adaption mechanism of A. acidoterrestris.

The aim of the research was to obtain a high healthcare honeysuckle beverage with strong antioxidant activity. Honeysuckle (Lonicera japonica Thunb) was used as the raw material in this experiment. The effects of fermentation temperature, fermentation time, lactic acid bacteria inoculation amount, and sugar addition amount on the sensory quality of honeysuckle beverage were investigated by single factor test and orthogonal test, and the best process was obtained. The physicochemical indexes and antioxidant activity of honeysuckle beverages fermented with lactic acid bacteria were studied. The results showed that the fermentation temperature of the beverage was 37 °C, the fermentation time was 24 h, the inoculation amount of Lactiplantibacillus plantarum and Lactobacillus acidophilus mixed starter (1:1) was 3%, and 8% white granulated sugar was added. The highest sensory score was 87.30 ± 0.17, which was the optimal process. The honeysuckle liquid mixed inoculation with Lactiplantibacillus plantarum and Lactobacillus acidophilus was fermented for 24 h. The number of viable bacteria reached 9.84 ± 0.02 lg cfu/mL, the pH value was 3.10 ± 0.01, and the total polyphenol content was 7.53 ± 0.03 mg GAE/g. The number of lactic acid bacteria, pH, total polyphenol content, and free radical scavenging rate were significantly increased (p < 0.05) compared with the non-inoculated and single-inoculated lactic acid bacteria. To sum up, it was concluded that a better quality beverage could be obtained by fermenting a solution of honeysuckle with Lactiplantibacillus plantarum and Lactobacillus acidophilus mixed fermentation agent, providing a new approach and new ideas for the development of deep processing and fermented beverages using honeysuckle.

The effect of mixed fermentation with sourdough and lactic acid bacteria (Lactobacillus plantarum and Streptococcus thermophilus), the physicochemical indexes, storage characteristics of dough and bun were investigated. Compared with sourdough-only dough and bun, the mixed fermentation significantly increase the total phenol, flavonoid and hydrolyzed amino acid content of the dough, the specific volume and height-diameter ratio of mixed fermentation bun increased significantly by 18.3 % and 7.9 %, respectively (P < 0.05), along with a significant improvement in sensory quality (P < 0.05), and exhibited enhanced skin whiteness (by 2.0 %), with an increase in stomatal density and porosity by 2.6 % and 16.5 %, respectively. During a nine-day storage period, the moisture content near the skin and bun core of steamed bun decreased by 3.9 %, and 1.6 %, respectively, and the aging enthalpy values of mixed fermentation bun were significantly lower than sourdough-only bun (P < 0.05). Mixed fermentation providing a theoretical basis for the development of novel steamed bun starters.

Heavy metal exposure is closely associated with gut microbe function and tolerance. However, intestinal microbe responses in children to different copper ion (Cu2+) concentrations have not yet been clarified. Here, in vitro cultivation systems were established for fecal microbe control and Cu2+-treated groups in healthy children. 16S rDNA high-throughput sequencing, meta-transcriptomics and metabolomics were used here to identify toxicity resistance mechanisms at microbiome levels. The results showed that Lactobacillus sp. and Lactococcus sp. exerted protective effects against Cu2+ toxicity, but these effects were limited by Cu2+ concentration. When the Cu2+ concentration was ≥4mg/L, the abundance of Lactobacillus sp. and Lactococcus sp. significantly decreased, and the pathways of antioxidant activity and detoxification processes were enriched at 2mg/L Cu2+, and beneficial metabolites accumulated. However, at high concentrations of Cu2+ (≥4mg/L), the abundance of potential pathogen increased, and was accompanied by a downregulation of genes in metabolism and detoxification pathways, which meant that the balance of gut microbiota was disrupted and toxicity resistance decreased. From these observations, we identified some probiotics that are tolerant to heavy metal Cu2+, and warn that only when the concentration limit of Cu2+ in food is 2mg/L, then a balanced gut microbiota can be guaranteed in children, thereby providing protection for their health.

Acid-responsive proteome expression profiles of Alicyclobacillus acidoterrestris ( A. acidoterrestris ) were analysed using label-free quantitative mass spectrometry to investigate its acid resistance mechanism at sublethal pH. Totally, 325 differential expression proteins were identified during acid stress at pH2.5 condition for 15 min, of which the expressions of 83 proteins were up-regulated and the other 242 proteins expressions were down-regulated. Differentially expressed proteins were mainly involved in organic nitrogen compounds metabolism, small molecule metabolism, organic acid metabolism and signal transduction. Overall, they were mapped into 97 metabolic pathways. Combination of KEGG pathway analysis and protein functional analysis suggested that the pH homeostasis system, changes in metabolic pathways, cell membrane permeability and DNA repair are the main acid resistance mechanisms of A. acidoterrestris at sublethal pH conditions. It is speculated that A. acidoterrestris may sense and transmit pH signals from the external environment through the nhaB protein which holds histidine-dependent acid resistance system, initiating a series of acid tolerance reactions. Our study demonstrated global physiological response of A. acidoterrestris to sublethal pH, which provided a better understanding of acid adaption mechanism of A. acidoterrestris .### Competing Interest StatementThe authors have declared no competing interest.