Search Results (108)

This study investigated the effects of Lactococcus lactis subsp. 1.2472 (L)-, Streptococcus thermophilus 1.2718 (S)-, and thermostable Lactobacillus rhamnosus HCUL 1.1901-1912 (T)-fermented rice flour with inoculum levels of 3–11% (w/w) on rice bread staling. Optimal staling resistance was achieved, as follows: 9% L-fermented rice bread (LRB), 7% T-fermented rice bread (TRB), and 5% S-fermented rice bread (SRB). Lactic acid bacteria-fermented rice flour significantly enhanced hydration properties. LF-NMR analysis revealed that T₂₁ (strongly bound water) and T₂₂ (weakly bound water) relaxation times decreased, while T₂₃ (free water) increased with prolonged storage. Fermented-rice-flour groups had significantly more strongly bound water than the control group on 7 d. The optimized formulations exhibited exceptional volumetric stability with specific volume change rates of 17.63% (LRB), 17.60% (TRB), and 19.58% (SRB), coupled with maximal porosities of 10.34%, 9.05%, and 9.41%, respectively. This study provides a theoretical foundation for improving rice bread’s anti-staling properties. Full article

The advancement of non-thermal disinfection technologies represents a critical pathway for ensuring food safety, meeting environmental sustainability requirements, and meeting consumer preferences for clean-label products. This study systematically evaluated the combined preservation effect of ultrasonic-assisted slightly acidic electrolyzed water (US+SAEW) on mirror carp fillets during refrigeration. Results demonstrated that US+SAEW exhibited superior antimicrobial efficacy compared to individual US or SAEW, achieving reductions of 0.73, 0.74, and 0.79 log CFU/g in total viable counts (TVC), Aeromonas bacteria, and lactic acid bacteria counts compared to the control, respectively. Furthermore, the combined intervention significantly suppressed microbial proliferation throughout the refrigeration period while simultaneously delaying protein and lipid degradation/oxidation induced by spoilage bacteria, thereby inhibiting the formation of alkaline nitrogenous compounds. Consequently, lower levels of pH, total volatile basic nitrogen (TVB-N), protein carbonyl, and thiobarbituric acid reactive substances (TBARS) were observed in US+SAEW compared to the other treatments. Multimodal characterization through low-field nuclear magnetic resonance (LF-NMR), texture, and color analysis confirmed that US+SAEW effectively preserved quality characteristics, extending the shelf life of mirror carp fillets by four days. This study provides a novel non-thermal preservation strategy that combines microbial safety maintenance with quality retention, offering particular advantages for thermolabile food. Full article

HPMC, regulating slurry properties, is widely used in cement-based materials. Research on the application of HPMC in gangue slurry is still in its early stages. Moreover, the interactive effects of various factors on gangue slurry performance have not been thoroughly investigated. The work examined the effects of slurry concentration (X₁), maximum gangue particle size (X₂), and HPMC dosage (X₃) on slurry performance using response surface methodology (RSM). The microstructure of the slurry was characterized via scanning electron microscopy (SEM) and polarized light microscopy (PLM), while low-field nuclear magnetic resonance (LF-NMR) was employed to analyze water distribution. Additionally, industrial field tests were conducted. The results are presented below. (1) X₁ and X₃ exhibited a negative correlation with layering degree and slump flow, while X₂ showed a positive correlation. Slurry concentration had the greatest impact on slurry performance, followed by maximum particle size and HPMC dosage. HPMC significantly improved slurry stability, imposing the minimum negative influence on fluidity. Interaction terms X₁X₂ and X₁X₃ significantly affected layering degree and slump flow, while X₂X₃ significantly affected layering degree instead of slump flow. (2) Derived from the RSM, the statistical models for layering degree and slump flow define the optimal slurry mix proportions. The gangue gradation index ranged from 0.40 to 0.428, with different gradations requiring specific slurry concentration and HPMC dosages. (3) HPMC promoted the formation of a 3D floc network structure of fine particles through adsorption-bridging effects. The spatial supporting effect of the floc network inhibited the sedimentation of coarse particles, which enhanced the stability of the slurry. Meanwhile, HPMC only converted a small amount of free water into floc water, which had a minimal impact on fluidity. HPMC addition achieved the synergistic optimization of slurry stability and fluidity. (4) Field industrial trials confirmed that HPMC-optimized gangue slurry demonstrated significant improvements in both stability and flowability. The optimized slurry achieved blockage-free pipeline transportation, with a maximum spreading radius exceeding 60 m in the goaf and a maximum single-borehole backfilling volume of 2200 m³. Full article

This study investigated quality changes in seaweed–yak patties before and after freeze–thaw by varying seaweed addition levels (10–70%). Macroscopically, the effects on water-holding capacity, textural properties, and oxidative indices of restructured yak patties were evaluated. Microscopically, the impact of seaweed-derived bioactive ingredients on patty microstructure and myofibrillar protein characteristics was examined. LF-NMR and MRI showed that 40% seaweed addition most effectively restricted water migration, reduced thawing loss, and preserved immobilized water content. Texture profile analysis (TPA) revealed that moderate seaweed levels (30–40%) enhanced springiness and minimized post-thaw hardness increases. SEM confirmed that algal polysaccharides formed a denser protective network around the muscle fibers. Lipid oxidation (MDA), free-radical measurements, and non-targeted metabolomics revealed a significant reduction in oxidative damage at 40% seaweed addition, correlating with increased total phenolic content. Protein analyses (particle size, zeta potential, hydrophobicity, and SDS-PAGE) demonstrated a cryoprotective effect of seaweed on myofibrillar proteins, reducing aggregation and denaturation. These findings suggest that approximately 40% seaweed addition can improve the physicochemical stability and antioxidant capacity of frozen seaweed–yak meat products. This work thus identifies the optimal seaweed addition level for enhancing freeze–thaw stability and functional quality, offering practical guidance for the development of healthier, high-value restructured meat products. Full article

Amid growing global concerns about environmental sustainability and food security, plant-based meat substitutes have emerged as a promising alternative to conventional meat. However, current formulations, especially those based on soy protein isolate (SPI) often fail to replicate the desired texture and structural integrity. To address this limitation, this study aimed to evaluate the use of whole yeast powder (WYP) combined with SPI for producing plant-based meat analogues via high-moisture extrusion. Seven groups were designed: a control group with 0% WYP, five treatment groups with 5%, 10%, 20%, 30%, and 40% WYP, and one reference group containing 20% yeast protein powder (YPP). Although lower in protein content than yeast protein powder (YPP), whole yeast powder exhibits superior water-binding capacity and network-forming ability owing to its complex matrix and fiber content. At a 20% inclusion level, whole yeast powder demonstrated a higher fibrous degree (1.84 ± 0.02 vs. 1.81 ± 0.04), greater hardness (574.93 ± 5.84 N vs. 531.18 ± 17.34 N), and increased disulfide bonding (95.33 ± 0.92 mg/mL vs. 78.41 ± 0.78 mg/mL) compared to 20% YPP. Scanning electron microscopy (SEM) and low-field nuclear magnetic resonance (LF-NMR) revealed that whole yeast powder facilitated the formation of aligned fibrous networks and enhanced water binding. Fourier transform infrared spectroscopy (FTIR) confirmed an increase in β-sheet content (0.267 ± 0.003 vs. 0.260 ± 0.003), which contributed to improved protein aggregation. Increasing the WYP content to 30–40% led to a decline in these parameters, including a reduced fibrous degree (1.69 ± 0.06 at 40% WYP) and weakened molecular interactions (p < 0.05). The findings highlight 20% WYP as the optimal substitution level, offering superior textural enhancement and fibrous structure formation compared to YPP. These results suggest that WYP is not only a cost-effective and processing-friendly alternative to YPP but also holds great promise for scalable industrial application in the plant-based meat sector. Its compatibility with extrusion processes and ability to improve sensory and structural attributes supports its relevance for sustainable meat analogue production. Full article

The gel performance of giant squid is weak. Researchers have confirmed that adding some substances could improve the texture. However, the flavor has not been taken into account. In a previous study, we proved that mixed inoculation with Lacticaseibacillus casei and Staphylococcus carnosus with several seasonings adding could improve the texture of squid. Whether the addition of seasonings could affect the quality of samples or not and how fermentation affects the texture and flavor were not clear. In present study, we prepared fermented squid without seasonings. The results showed that compared with fermented samples with added seasonings, samples without seasonings might be safer, with fewer types and lower concentrations of biogenic amines. In samples without seasonings, non-inoculation had a higher pH and higher levels of biogenic amines. Meanwhile, mixed inoculation with L. casei and S. carnosus could ensure safety, improve texture and rheological properties. The water state of the fermented sample was also changed. The microstructure indicated that good network was formed in the fermented sample. After fermentation, the contents of several organic acids, free amino acids and volatile flavor compounds increased, and the results of the electronic nose test were also changed. In addition, starters were dominant during fermentation. These results indicated that mixed inoculation without seasonings might be a safer method than that with seasonings. In addition, mixed inoculation without seasonings could improve the texture and flavor of the squid. These results lay the foundation for improving fermented squid quality in further studies. Full article

This study systematically investigates the effects of shell ash (SA) content (0–10%) on early moisture evolution, pore structure, and hydration kinetics in cement paste using LF-NMR and NG-I-D hydration kinetic models. Key findings include the following: (1) Increased SA content significantly alters moisture phase distribution. Low contents (≤8%) consume free water through rapid CaO hydration, promoting C-S-H gel densification. However, 10% SA causes reduced moisture in 0.16–0.4 μm gel micropores (due to hindered ion diffusion) and abrupt increases in 0.63–2.5 μm pores. (2) Porosity first decreases then increases with SA content, reaching minimum values at 3–5% and 8%, respectively. The 10% content induces abnormal porosity growth from localized over-densification following polynomial fitting (R² = 0.966). (3) Krstulovic–Dabic model analysis reveals three consecutive hydration stages: nucleation–growth (NG), phase boundary reaction (I), and diffusion control (D). The NG stage shows the most intense reactions, while the D stage dominates (>60% contribution), with high model fitting accuracy (R² > 0.9). (4) SA delays nucleation/crystal growth, inducing needle-like crystals at 3% content. Mechanical properties exhibit quadratic relationships with SA content, achieving peak compressive strength (18.6% increase vs. control) at 5% SA. This research elucidates SA content thresholds governing hydration kinetics and microstructure evolution, providing theoretical support for low-carbon cementitious material design. Full article

The large-scale reuse of shield tunneling muck remains a major challenge in urban construction. This study proposes a geopolymeric-controlled low-strength material (GC-CLSM) utilizing shield tunneling muck as the primary raw material and a novel alkali-activated binder composed of ground granulated blast-furnace slag (GGBFS) and carbide slag (CS). Emphasis is placed on early-age strength development and its underlying mechanisms, which were often overlooked in previous CLSM studies. Among the tested mixtures, a GGBFS:CS ratio of 80:20 yielded the best balance between early and long-term strength. Its 1-day UCS reached 1.18–1.75 MPa, representing a 6.3–23.6-fold increase over the low-CS reference (90:10), which achieved only 0.05–0.31 MPa. However, excessive CS content (e.g., 60:40) led to a significant reduction in the 28-day strength—up to nearly 50% compared with the 90:10 mix—due to impaired microstructural densification. Microstructural analyses (pore-solution pH, SEM, EDS, XRD, FTIR, LF-NMR) confirmed that higher CS levels enhanced early C–A–S–H gel formation by increasing OH⁻ and Ca²⁺ availability while compromising long-term structure. Additionally, the GC-CLSM system reduced carbon emissions by 68.6–70.3% per ton of treated shield tunneling muck compared with conventional cement-based CLSM. Overall, this study offers a sustainable and performance-driven approach for the valorization of shield tunneling muck, enabling the development of early-strength controllable, low-carbon CLSM for infrastructure applications. Full article

Rice-field eel (Monopterus albus) slices, an important aquatic product in Southeast Asia, are prone to spoilage and deterioration during cold chain storage. In this study, the effects of a composite preservative (ε-polylysine, Vitamin C (Vc), epigallocatechin gallate (EGCG), and phloretin) on the muscle quality (color, texture, water holding capacity (WHC)) of rice-field eel slices during refrigeration storage at 4 °C for up to 7 days was investigated, and the underlying mechanism was elucidated by the integrated microbiome and metabolomics, in addition to Elisa and Low-Field Nuclear Magnetic Resonance (LF-NMR). After 7 days of storage, the WHC, shear force, and a* decreased by 11.39%, 34.37%, and 49.20% in treated samples, and by 19.18%, 38.38%, and 54.87% in control samples, respectively. The addition of the composite preservative significantly increased Hexokinase, Pyruvate kinase, and Creatine kinase, while it decreased the total viable count (TVC), total volatile basic nitrogen (TVB-N), thiobarbituric acid reactive substance (TBARS), and Lactic acid. Preservative treatment maintained the moisture content of the eel slices during storage and prevented bright red oxymyoglobin from transforming into brown metmyoglobin. Microbiota composition (especially Pseudomonas) and metabolic pathways (including amino acid and its metabolites, nucleotide and its metabolite, and organic acid and its derivatives, etc.) were obviously altered by the preservative treatment. Pseudomonas, tryptophan-aspartic acid (Trp-Asp), D-Glucose 6-phosphate, Succinic Acid, Biliverdin 1, 5-Diaminopentane, and Tyramine, etc., are potential biomarkers for the quality changes of eel slices during refrigeration. These findings provide an in-depth understanding of the improvement of the eel slice quality during refrigeration storage by the composite preservative. Full article

The spatiotemporal heterogeneity of moisture distribution causes the coal pillar dams in underground water reservoirs to undergo long-term dry–wet cycles (DWCs) under varying moisture content increments (MCIs). Accurately measuring the pore damage and fractal dimensions (D_f) of coal rock by different MCIs under DWCs is a prerequisite for in-depth disclosure of the strength deterioration mechanism of underground reservoir coal pillar dams. This study employed low-field nuclear magnetic resonance (LF-NMR) to quantitatively characterize the pore structural evolution and fractal dimension with different MCI variations (Δw = 4%, 6%, 8%) after one to five DWCs. The results indicate that increasing MCIs at constant DWC numbers (N_DWC) induces significant increases in pore spectrum area, adsorption pore area, and seepage pore area. MRI visualization demonstrates a progressive migration of NMR signals from sample peripheries to internal regions, reflecting enhanced moisture infiltration with higher MCIs. Total porosity increases monotonically with MCIs across all tested cycles. Permeability, T₂ cutoff (T_2C), and D_f of free pores exhibit distinct response patterns. A porosity-based damage model further reveals that the promoting effect of cycle numbers on pore development and expansion outweighs that of MCIs at N_DWC = 5. This pore-scale analysis provides essential insights into the strength degradation mechanisms of coal pillar dams under hydro-mechanical coupling conditions. Full article

Microbial transglutaminase (mTG) is most frequently utilized in order to increase the gelling properties of soybean protein isolate (SPI), but there are still some limitations of mTG-based hydrogel fabrication technology. Therefore, we aimed to develop a dual modification technique based on enzyme plus organic acid treatment to fabricate SPI hydrogels with high gel strength and stability. Our results showed that mTG plus glucose-δ-lactone (GDL), lactobionic acid (LBA) or maltobionic acid (MBA) treatment could significantly improve the gel strength, textural properties, and water-holding capacity of SPI hydrogels. Also, the addition of these organic acids remarkably reduced the surface hydrophobicity (H₀) and intrinsic fluorescence as well as increased the storage modulus (G′), loss modulus (G″) values, average particle size, and the absolute value of zeta potential of samples. GDL, LBA, or MBA greatly increased the β-sheet level and decreased the α-helix level in hydrogels, as well as dissociated 11S subunits of SPI into 7S subunits. Notably, covalent interactions, hydrogen bonding, and hydrophobic interactions of three organic acids with SPI, as well as the effects of organic acids on the interactions among the intramolecular and intermolecular forces of SPI molecules, contributed to their promoting effects on the formation of hydrogels. The LF-NMR and SEM analyses confirmed the effects of GDL, LBA, and MBA on converting the free water into immobilized and bound water as well as forming a dense stacked aggregate structure. Therefore, GDL, LBA, and MBA are promising agents to be combined with mTG in the fabrication of SPI hydrogels with high gel strength and stability. Full article

The aging of asphalt mixtures has a significant impact on the service life of asphalt pavements. Currently, the commonly employed method for assessing aging involves the extraction of asphalt from asphalt mixtures using the Abson method. However, this method is known to be detrimental to the extracted asphalt samples, time-consuming, and environmentally unfriendly. This study explored a novel non-destructive method for assessing asphalt aging, known as low-field nuclear magnetic resonance (LF-NMR). It primarily investigated the influence of asphalt content in asphalt mixtures on the patterns of LF-NMR spectra. Specifically, it examined the effect of asphalt content on LF-NMR spectra in asphalt mixtures with varying particle sizes and aging levels at the same detection temperature. Additionally, machine learning was used to establish predictive models linking NMR spectral features to asphalt mixture aging levels, enhancing interpretation accuracy. The research results revealed the following: (1) Spectral parameters such as peak height, normalized peak area, and normalized total peak area had a significant impact on the first principal component of LF-NMR spectra. (2) Asphalt content in the mixture increased as particle size decreased, leading to corresponding changes in the LF-NMR spectra. (3) There was a strong correlation between the aging degree of asphalt and asphalt mixtures and the normalized total peak area of their LF-NMR spectra. The study provides a non-destructive method to assess asphalt mixture aging, enabling timely maintenance decisions and improving pavement durability. Full article

The pore structure of reservoir rocks was a crucial factor affecting hydrocarbon production. Accurately characterized the micropore structure of different types of rock reservoirs was of great significance for unconventional natural gas exploration. In this study, multiple observation methods (field emission scanning electron microscope (FESEM) and low-field nuclear magnetic resonance (LFNMR)) and physical tests (mercury injection capillary pressure (MICP)) were employed, and double logarithmic plots for fractal fitting were illustrated. The fractal dimension of 15 samples was calculated using fractal theory to systematically investigate the pore–fracture structure and fractal characteristics of hydrocarbon source rock (limestone, mudstone, and sandstone) samples from the Late Carboniferous Taiyuan Formation in the Huainan coalfield. MICP experiments revealed that sandstone reservoirs had larger and more uniformly distributed pore throats compared to mudstone and limestone, exhibiting superior connectivity and permeability. The T₂ spectrum characteristic maps obtained using LFNMR were also consistent with the pore distribution patterns derived from MICP experiments, particularly showed that sandstone types exhibited excellent signal intensity across different relaxation time periods and had a broader T₂ spectrum width, which fully indicated that sandstone types possess superior pore structures and higher connectivity. FESEM experiments demonstrated that sandstone pores were highly developed and uniform, with sandstone fractures dominated by large fractures above the micrometer scale. Meanwhile, the FESEM fractal dimension results indicated that sandstone exhibits good fractal characteristics, validating its certain oil storage capacity. Furthermore, the FESEM fractal dimension exhibited a good correlation with the porosity and permeability of the hydrocarbon source rock reservoirs, suggesting that the FESEM fractal dimension can serve as an important parameter for evaluating the physical properties of hydrocarbon source rock reservoirs. This study enriched the basic geological theories for unconventional natural gas exploration in deep coal-bearing strata in the Huainan coalfield. Full article

The ionic soil stabilizer (ISS) can synergistically enhance the mechanical properties and improve the engineering characteristics of iron tailings soil in conjunction with cementitious materials such as cement. In this paper, the influence of ISS on the cement hydration process and the charge repulsion between iron tailings soil particles was studied. By means of Isothermal calorimetry, X-ray diffraction (XRD), Scanning electron microscope (SEM), and Low-field nuclear magnetic resonance microscopic analysis methods such as (LF-NMR), X-ray photoelectron spectroscopy (XPS), Non-evaporable water content and Zeta potential were used to clarify the mechanism of ISS-enhanced cement stabilization of the mechanical properties of iron tailings soil. The results show that in the cement system, ISS weakens the mechanical properties of cement mortar. When ISS content is 1.67%, the 7 d compressive strength of cement mortar decreases by 59.8% compared with the reference group. This retardation arises due to carboxyl in ISS forming complexes with Ca²⁺, creating a barrier on cement particle surfaces, hindering the hydration reaction of the cement. In the cement-stabilized iron tailings soil system, ISS has a positive modification effect. At 0.33% ISS, compared with the reference group, the maximum dry density of the samples increased by 6.5%, the 7 d unconfined compressive strength increased by 35.3%, and the porosity decreased from 13.58% to 11.85%. This is because ISS reduces the double electric layer structure on the surface of iron tailings soil particles, reduces the electrostatic repulsion between particles, and increases the compactness of cement-stabilized iron tailings soil. In addition, the contact area between cement particles increases, the reaction energy barrier height decreases, the formation of Ca(COOH)₂ reduces, and the retarding effect on hydration weakens. Consequently, ISS exerts a beneficial effect on augmenting the mechanical performance of cement-stabilized iron tailings soil. Full article

The reliability of the “last mile” of cold-chain logistics is crucial for food safety. This study investigated the effect of different packaging treatments on the quality of anhydrously preserved live Ruditapes philippinarum (R. philippinarum) in “last mile” cold chain disruption. The temperature profiles of three packaging treatments at ambient temperature (25 °C) were monitored. Quality assessment was conducted based on sensory scoring, survival rate, total viable count (TVC), water-holding capacity (WHC), pH, total volatile basic nitrogen (TVB-N), thiobarbituric acid-reactive substances (TBA), color, and texture. Low-frequency nuclear magnetic resonance (LF-NMR) and magnetic resonance imaging (MRI) were utilized to characterize the water state profile. The findings demonstrated a progressive increase in internal package temperature throughout the “last mile”, with packages containing additional ice packs more effectively maintaining lower temperature and restricting the migration of “hot spots” towards the center. Specifically, the package with three ice packs maintained a markedly lower temperature, which effectively inhibited microbial activity, lipid oxidation, and the production of alkaline substances, resulting in higher survival rates, water-holding capacity, texture, sensory acceptability, and immobilized water fraction. Furthermore, LF-NMR relaxation parameters showed strong correlations with various physicochemical indices, suggesting a potential approach for real-time quality monitoring. This study provides insights for maintaining live R. philippinarum quality during the “last mile”. Full article