Food Biophysics最新文献

This study examined the effect of sonication conditions on the extraction rate of Inonotus obliquus polysaccharides (IOPs) through a single-factor experiment. Meanwhile, the Box-Behnken design was utilized to optimize the sonication-assisted extraction technology. On the basis of polysaccharide yields, the optimal IOPs extraction rate (4.13%) was achieved with ultrasonic time (31 min), ultrasonic frequency (28 kHz), ultrasonic temperature (63℃) and a solid-to-liquid ratio of 1:20 g/mL. The empirical data obtained from these reactions closely align with the theoretical values generated by the mathematical model. Antioxidant experimental results indicated that the scavenging abilities of the polysaccharides from IOPs on DPPH radicals, hydroxyl radicals, and superoxide anion radicals were positively correlated with their concentration, with maximum scavenging rates of 64.1%, 65.7%, and 34.1%, respectively, suggesting that the IOPs possess strong antioxidant activity. The structure of the IOPs was analyzed using the ultraviolet and infrared spectra. The results revealed that IOPs were pyranose cyclic polysaccharides with β-glycosidic bonds, carbonyl groups, hydroxyl groups, and other functional groups. This confirms the feasibility of ultrasonic-assisted extraction for IOPs, indicating its potential application in pharmaceutical extraction research. This study laid a foundation for further development and utilization of Inonotus obliquus.

Porang glucomannan (PGM) is widely used as a functional ingredient in food and non-food products. However, the PGM industry still faces low PGM yield, which is a significant challenge in extracting PGM from porang flour (PF) using mechanical method (milling process aided by a wind-sifter). Natural deep eutectic solvents (NADES) are promising green solvents for glucomannan extraction. This study aimed to investigate the influence of stirring speed, PF particle size, filter pore size, and solvent recycling on characteristics of PGM using NADES composed of betaine and 1,2-propanediol at a 30% (W_water/W_total) hydration level (BPG14_70%). The PGM was characterized by glucomannan content, crystallinity, gel properties, morphology, and particle size distribution. The findings showed that increasing filter pore size and stirring speed improved the purity and viscosity of PGM. The PF particle size was the primary factor in glucomannan extraction, in which a smaller PF particle size reduced crystallinity and impurities surrounding the surface of PGM, resulting in higher purity and improved gel properties (firmer and springier gel). The suggested conditions for glucomannan extraction were a stirring speed of 800 rpm, a filter pore size of 149 μm, and a PF particle size of 257 μm. These conditions resulted in 76% PGM yield with a glucomannan content of 93% and strong gel properties. Additionally, after reusing five cycles, BPG14_70% could be recovered ranged 84–78%, producing PGM with a purity above 80%. Our findings offer an extraction technology to produce a high yield of purified PGM with a low environmental load.

Contamination by toxigenic fungi presents a significant challenge in nut preservation, with unpacked nuts exhibiting a higher infection rate of 35% compared to 5% in packed nuts. This study investigates the application of chili and garlic oleoresin nanoparticle coatings as a novel method for improving nut preservation and reducing aflatoxin contamination. Oleoresins were characterized for bioactive content and oxidative stability. Nanoparticle membranes were formulated using 1.5% carboxymethyl cellulose and 4.5% Arabic gum, reinforced with maltodextrin (CF1) or alginate (CF2). The results demonstrated that chili oleoresin enhanced the tensile strength of maltodextrin-based membranes from 1.71 MPa to 13.99 MPa, while garlic oleoresin improved the mechanical robustness of alginate membranes from 6.05 MPa to 27.18 MPa. Structural analysis using SEM confirmed changes in membrane architecture due to oleoresin incorporation. Chili oleoresin nanoparticles increased the oxidative stability of nut oils, prolonging induction periods by 23.1 h for hazelnut oil and 10.4 h for almond oil compared to controls. Garlic oleoresin-loaded composite film CF2 reduced total fungal load by 78.4% and aflatoxin B₁ levels by 85.2% after 30 days of storage at 25 C. Chili oleoresin films showed a 72.1% reduction in fungal load. This study recommends the application of alginate-supported garlic oleoresin coatings as a potent biodegradable strategy for nut preservation and mycotoxin risk mitigation. Nano-emulsified chili oleoresin coatings achieved a 100% reduction in aflatoxin contamination in artificially inoculated peanut samples, whereas garlic nanoemulsion reduced aflatoxin levels by 87.97%. These findings highlight the potential of edible oleoresin-based nanoparticle coatings as an effective, sustainable strategy for nut safety enhancement.

This study presents a comprehensive modelling framework for analyzing mass transfer and biophysical changes in kale leaves (Brassica oleracea var. acephala) during cryo-osmotic dehydration enhanced by dielectric (radio frequency, RF) heating. A custom-designed system employing precooled sucrose solutions (50–60%, 1–5 °C) enabled controlled dehydration over 3–9 h, while RF heating (27.12 MHz, 1.5 kW) promoted internal moisture migration under low-temperature conditions. Moisture loss, solute uptake, and temperature distribution were simulated using Fick’s second law of diffusion and a semi-empirical RF heating model. The effective moisture diffusivity (Dₑff) ranged from 1.8 × 10⁻⁹ to 3.6 × 10⁻⁹ m²/s, increasing significantly with sucrose concentration and temperature (p < 0.05), indicating adjustable dehydration rates that can be tailored to product sensitivity. The dielectric loss factor and RF penetration depth, modelled as functions of moisture content, identified optimal energy absorption in samples 1.5–2.5 cm thick, informing equipment design for uniform internal heating. Experimental validation showed strong agreement between model predictions and observed values for weight loss, chlorophyll retention, and firmness (R² >0.92), demonstrating the reliability of the models for quality control. By integrating cryo-osmotic dehydration with RF-assisted heating, an underutilized combination in leafy vegetable processing, this study advances mechanistic understanding of coupled heat and mass transfer during non-thermal food preservation. The modelling framework offers a scalable basis for process optimization and supports the development of energy-efficient, nutrient-retentive technologies for minimally processed vegetable products.

Clinical Trial Number Not applicable.

This study aimed to evaluate the physicochemical properties and antimicrobial efficacy of the encapsulated microcin J25 variant G12Y [MccJ25(G12Y)] using brea gum (BG) as a carrier matrix via spray-drying. The encapsulation process yielded 67% (w/w), producing a fine, homogeneous, non-agglomerated powder with a Sauter mean diameter of 12.2 ± 0.5 μm, high encapsulation efficiency, and stability for at least 120 days at 4 °C or 25 °C. The powder exhibited low moisture content (7.55 ± 0.17%) and water activity (0.27 ± 0.03), ensuring physical stability. Sorption isotherms indicated pronounced moisture uptake above 0.55 aw, consistent with the hydrophilic nature of the matrix. GAB modeling outperformed BET (R² > 0.90), supporting a thermodynamically favorable and exothermic water-sorption process. The identity and purity of the purified MccJ25(G12Y) peptide were confirmed using MALDI-TOF mass spectrometry. A monoisotopic mass of 2212 Da was experimentally determined for the first time, in full agreement with the theoretical mass increase expected from the glycine-to-tyrosine substitution at position 12 of the parental MccJ25. In vitro antimicrobial assays against foodborne Gram-negative pathogens, including Salmonella, Escherichia, Shigella, and Enterobacter spp., showed effective concentrations ranging from 0.6 to 9.4 mg/mL. Efficacy was further confirmed in a ground beef model, where the treatment with 4 mg/g of the powder reduced Escherichia coli O157 (NCTC 12900) viability by approximately 4 log CFU/g in 72 h. Encapsulated MccJ25(G12Y) in brea gum presents a promising strategy for food biopreservation, offering a stable powder with extended antimicrobial functionality and demonstrated effectiveness in food systems.

Sodium alginate (SA) is a kind of seaweed-derived bioactive polysaccharides with broad application prospect, but the poor solubility and high viscosity associated with high molecular weight astricts its biological activities, low molecularization is an effective strategy for overcoming the defects. This work depolymerized SA using ultrasound and assessed the effect of reducing molecular weight on viscosity, antioxidation and anticoagulation of SA. Results indicate that, after ultrasound treatment at 50 ℃, 450 W for 1.5 h, 2.5 h and 4 h, weight-average molecular weight (Mw) of SA significantly declined from original 118.41 kDa to 52.37 kDa, 37.54 kDa and 32.14 kDa, respectively, conforming to a second-order kinetic model, which corresponded to the continuous decrease of viscosity of degradation products, but no alteration of spectral characteristics and monosaccharide composition was observed. Differently, there was no consistent bioactive change with the viscosity. Among SA and its three low molecular weight (LMW) forms, 37.54 kDa of LMW-SA presented the highest anticoagulant property demonstrated by the values of activated partial thromboplastin time (APTT) and prothrombin time (PT), especially APTT. Interestingly, discrepant scavenging capacities of SA and the three LMW-SAs on different radicals were observed, along with Mw. decrease of SA, scavenging rates of DPPH and hydroxide radical were continuous reduction, but the ability of scavenging superoxide anion was increase and the platform value reached at the treatment for 2.5 h. These findings provide an important theoretical basis for the low-molecular-weight modification of SA, potentially improving biological properties and advancing application in biomedical and industrial fields.

The effects of assisted extraction with high voltage pulsed electric field (PEF) of phosvitin (Pv) from black carp roe on extraction rate, protein structure, physicochemical properties, antioxidant activity, degree of enzymatic hydrolysis, and antioxidant activity were investigated. The number of pulses and the electric field intensity were varied. Compared to the untreated sample, when the pulse number was 12 and the electric field intensity was 20 kV/cm, the extraction rate of Pv was increased by 1.10%, and the emulsification activity and emulsion stability increased to 22.15 m²/g and 54.02%, which was 2.95 m²/g and 4.84%, respectively. The denaturation temperature of Pv decreased from 118.33 to 103.78 ℃, and the 2,2-diphenyl-1-picrylhydrazyl radical scavenging ability and Fe²⁺ ion chelating ability increased to 45.38% and 74.30%, which were 2.02% and 7.64% higher, respectively. Meanwhile, the molecular weight and the number of subunits of Pv were unchanged, and the secondary structure changed from β-sheet to random coil and β-turn. Scanning electron microscopic analysis showed that the application of PEF did not damage the Pv surface. After assisted extraction with PEF, Pv was hydrolyzed by alkaline protease and trypsin to obtain phosphopeptides (PP), with a degree of hydrolysis of 39.03 ± 0.28%, total antioxidant capacity of 263.16 ± 17.19 µmol/100 mg, Fe²⁺ chelating ability of 86.86 ± 1.66%, and the surface hydrophobicity was enhanced. All these values were significantly higher than the untreated group, facilitating the chelation of PP with metal ions to produce metal ion bio-supplements. The relationship between the structural changes and functions of Pv after assisted extraction with PEF was elucidated.

This study focused on the inhibition of melanosis formation, shelf-life extension, and the correlation between quality indices under different treatment conditions during the storage of Pacific white shrimp at 0 °C. The treatment groups included: a control sample, samples treated with 0.5% benzaldehyde solution, samples treated with 2% chitosan solution, and samples treated with a combination of 0.5% benzaldehyde and 2% chitosan. Sensory, chemical, and microbiological evaluation methods were applied using quality indicators such as melanosis score, TVB-N, TMA-N, hypoxanthine, and TVC. TVC results demonstrated that the antibacterial and antioxidant properties of benzaldehyde and chitosan extended the shelf life to 12 days (benzaldehyde), 11 days (chitosan), and 15 days (benzaldehyde/chitosan), compared to 8 days for the control. The formation of a Schiff base from the reaction between benzaldehyde and tyrosine was shown to inhibit tyrosinase activity, thereby reducing melanosis. The benzaldehyde and benzaldehyde/chitosan samples maintained acceptable melanosis scores (≤ 6) up to days 12 and 15, respectively, compared to days 8 and 11 for the control and chitosan samples. Changes in TVB-N and TMA-N were analyzed across two stages, autolysis and decomposition, allowing for the development of linear regression equations with high correlation coefficients (R² ≈ 0.99). Similar linear trends were observed for melanosis and hypoxanthine. The study established strong linear correlations between melanosis score, TVB-N, TMA-N, and hypoxanthine across all treatment groups, providing a foundation for predictive modelling of shrimp quality under different preservation conditions.

The application of blue laser irradiation at 405 nm has attracted significant attention for its potential in microbial control for food safety and food processing. This study investigates the effects of low-level laser irradiation (LLLI) on Saccharomyces cerevisiae, a key microorganism of industrial food fermentation. Using 100 mW and 300 mW power outputs, the impact of varying laser exposure times (10–40 min) on the yeast cells was assessed through growth kinetics, cell viability assays, protein analysis, and morphological studies. Results revealed that 100 mW irradiation did not significantly affect cell viability or growth, aligning with the principles of the Arndt-Schultz law. Conversely, 300 mW irradiation induced a bio-inhibition response, with cell viability dropping to 65% after 40 min. SDS-PAGE analysis indicated significant alterations in protein profiles, including lighter bands at higher molecular weights, suggesting protein aggregation or degradation due to reactive oxygen species (ROS) production. Morphological analysis highlighted disrupted cell cycle progression and reduced cell size under 300 mW irradiation, particularly affecting the S and G2 phases. These findings demonstrate the potential of blue laser irradiation as a non-invasive tool strategy for microbial control in food safety optimization.

To address the issue that the exudate from fish accelerates the spoilage process, a sustained-release absorbent pad (BC-F/AP) was developed. This pad consisted of a chitosan/sodium alginate (CS/SA) sheet containing a basil essential oil inclusion complex (BEO-IC) combined with an absorbent pad (AP). The effects of BC-F/AP on quality maintenance and myofibrillar protein (MP) stability in large yellow croaker (Larimichthys crocea) were investigated in comparison with the control (CK), commercial pad (AP), pure BEO, and BEO-IC. The findings showed that the BC-F/AP group suppressed the proliferation of psychrophilic bacteria in fish fillets and minimized cooking loss. On day 10, the microbial count of BC-F/AP group (9.45 log CFU/g) was lower than the CK group (10.47 log CFU/g), and the cooking loss was reduced by 3.08%. At the same time, it significantly suppressed protein deterioration: TCA-soluble peptide content decreased by 1.39 µmol tyrosine/g, MFI by 46.82, surface hydrophobicity by 7.33 µg BPB/mg protein, and turbidity by 0.59. In vitro experiments by incubating exudate with MPs confirmed that the exudate accelerated the degradation and oxidation of MPs in decreasing protein content and intrinsic fluorescence intensity, and increasing surface hydrophobicity and particle size. In conclusion, the BC-F/AP group maintained the quality of the large yellow croaker and the integrity of MPs by absorbing exudate and sustained-releasing antibacterial and antioxidant activity.