Food Biophysics最新文献

High pressure processing (HPP) have the potential to be used as an alternative to commercial thermal processing of honey. Its impact on the antioxidant and antibacterial properties of honey have yet to be understood properly. This study focuses on the effects of HPP on the antioxidant and antibacterial properties of honey. Six different honey samples were subjected to HPP at 400 and 600 MPa for 10 and 15 min. The antioxidant properties were measured in terms of total phenolic content, total flavonoid content, the 2,2-diphenyl-1-picrylhydrazyl free radical scavenging assay, and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) free radical scavenging assay. The antibacterial activity was measured as the minimum bacteriocidal and minimum bacterial inhibition concentration of honey against S. aureus, P. aeruginosa and E. coli. HPP decreased the total phenolic content and increased the total flavanoid content. There was an increase in the antibacterial activity of HPP honey against S. aureus, whereas no significant changes were observed against P. aeruginosa, and E. coli. It was evident that the changes in the antioxidant and antibacterial activity of honey samples were dependent on the HPP processing parameters and the type of honey.

The use of natural antimicrobial peptides is a viable preservation alternative in the production of safe and good-quality products for consumption. Nanoliposomes containing nisin were prepared by film hydration with phosphatidylcholine (PC) and cholesterol, and coated with the polyelectrolytes (PEs) chitosan, cationic maltodextrin or poly-L-lysine (PLL), and characterized in their physical, thermal, functional and storage stability properties. As results, nisin encapsulation efficiency was around 90% for all formulations. The average diameter varied between 93.2 and 115.8 nm, with an increase in size after incorporation of PE, and the zeta potential ranged from + 11.3 to + 23.9 mV. These physical parameters showed good stability during 60 days of refrigeration (4 °C). The thermal characteristics of the liposomes were studied by thermogravimetric analysis (TGA) and differential scanning calorimetry (DSC). An improvement in the thermal stability of liposomes coated with PEs was observed. Infrared spectroscopy (FTIR) revealed predominantly PC peaks as the bulk component of the nanostructures, but representative peaks of PEs and nisin suggested their presence on the surface of liposomes. Finally, antimicrobial activity was observed against Gram-positive bacteria (L. monocytogenes, S. aureus, and B. cereus) and Gram-negative bacteria (E. coli and S. enterica), in brain heart infusion (BHI), whole, and skimmed milk agar. The formulations containing PEs and nisin maintained the physical properties and antimicrobial activity after 60 days of storage. Therefore, liposomes coated with cationic PEs have the potential to deliver antimicrobial peptides to reduce undesirable bacteria in foods.

Nanoencapsulation of essential oils exhibited promising applications in food industries, especially in controlling spoilage due to food-borne microbes. In this study, the enhanced antimicrobial efficacy of nanoencapsulated Cuminum cyminum essential oil (Ne-CEO) against food-borne molds, and aflatoxin B₁ contamination was observed in a dose-dependent manner. The GC-MS results represent 14 different volatile organic compounds of (CEO) (94.49%), where cuminaldehyde was found to be the major one. The interaction of the Cuminum cyminum essential oil (CEO) and chitosan nanoparticles (CSNPs) was confirmed with the Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR) analysis. The Ne-CEO exhibited superior antimicrobial effects compared to non-encapsulated CEO and inhibited the growth of selected mold species (0.3–0.5 µL/mL) and aflatoxin B₁ (AFB₁) secretion at 0.4 µL/mL. The probable toxicity mechanism results show membrane impairment and cellular homeostasis linked with decreased ergosterol content, increased cation leakage, impairment in antioxidant defenses, carbon metabolism, and transcriptional genes (Ver-1 and Nor-1) functioning of AFB₁ biosynthesis. Furthermore, during the six months in-situ trial, Ne-CEO (0.4 µL/mL) remarkably protected the biodeterioration of A. hypogaea seed samples against A. flavus growth and AFB₁ contamination, thus enhancing its practical application as a plant-based food preservative to enhance the shelf-life of food commodities.

This study was aimed to determine the effects of various fruit juices used as impregnation solutions on the physicochemical, textural and sensory properties of dried chicken meat cubes. The pH, color parameters, total phenolic, antioxidant activity, water holding capacity, textural (TPA) and sensorial properties of the cubes were tested. Impregnation solutions used in the treatment groups were prepared with pomegranate, black grape and black mulberry juices, and salt solution (control). Impregnation was performed in two replicates and two samples were analyzed per replicate. The cubes were immersed in the solutions and the 10 min vacuum (250 mbar absolute pressure) − 10 min atmospheric pressure cycle was repeated at 4 °C for 2 h. pH values decreased (P < 0.01) by impregnation with various anthocyanin-rich fruit juices. Total phenolic and antioxidant activity were the highest (P < 0.01) in samples impregnated with pomegranate juice and were 720.71 mg GAE/kg and 840.22 mg TE/kg, respectively. The use of anthocyanin-rich fruit juices as impregnation solution decreased a* and b* values of samples (P < 0.01; P < 0.05, respectively). The TPA results indicated that impregnation with pomegranate, black grape and black mulberry juices induced lower (P < 0.01) hardness and higher (P < 0.05) adhesiveness values compared to the control. Consequently, the impregnation with anthocyanin-rich fruit juices such as pomegranate, black grape and black mulberry has the potential to improve the quality properties of dried chicken cubes.

Supercooling preservation of fruits and vegetables (FV) is critical to food freezing. Magnetic field (MF)-assisted freezing of FV promotes supercooling; but its phenomenon is yet to be uncovered. Therefore, information on the supercooling phenomenon of MF-assisted freezing and its impacts on the quality preservation of frozen FV is critical to cellular food freezing manufacturing practices. This study reported on the supercooling phenomenon of MF-assisted freezing and its impacts on the quality preservation of frozen FV. Intrinsic factors (hydrogen bonding ordering and geometry) related to product, and extrinsic factors (types of magnetic field, field intensity, and exposure time) related to process parameters, that influenced supercooling were discussed. The study revealed that the occurrence of supercooling during MF-assisted freezing depends mainly on the types of magnetic field applied, field intensity and the direction of the applied field, which affects the effective magnetic lines of force resulting to uncompensated electron spins through samples. The exhibition of electron spins increases the order of magnetic ions and water molecules contained in cellular foods. For process design, more in-depth study and accurate understanding of the supercooling phenomenon of MF-assisted freezing and its impacts on the quality preservation of frozen FV are essential. It is hoped that this study provide better insight on the supercoling phenomenon of MF-assisted freezing and its impacts on the quality preservation of frozen FV for further studies.

Practical Applications: Application of high intensity magnetic field to cellular food freezing assists supercooling phenomenon, with advantage of enhancing quality. But the development as well as market acceptance of the technology is low because the supercooling phenomenon is not well-understood. Currently, insightful studies on the supercooling phenomenon of magnetic field-assisted freezing and its impacts on quality preservation of fruits and vegetables have been unveiled. The studies revealed that the strong magnetic field assistance to freezing is possible through the exhibition of electron spins and re-ordering of magnetic ions of water molecules contained in cellular foods. However, the results outlined in this study offer comprehensive insights into the supercooling phenomenon of magnetic field-assisted freezing and its impacts on the freezing process and the quality preservation of fruits and vegetables, offering valuable guidance for future developments of strong magnetic field-assisted freezing technology.

This study investigates the metabolite diversity of twelve Japanese plum cultivars grown in South Africa to understand their differential organoleptic characteristics and nutritional properties. The goal is to differentiate or associate these plum cultivars based on their metabolic profiles. Metabolite profiling was conducted using gas chromatography-mass spectrometry (GC-MS) at different postharvest ripening stages. Different unsupervised machine learning algorithms were applied: hierarchical clustering, K-means clustering, Density-Based Spatial Applications with Noise, and principal component analysis (PCA). Results revealed that each cultivar contains a unique combination of 13 amino acids, 4 sugars (contributing to organoleptic characteristics), and numerous phenolic compounds and antioxidant activities (contributing to nutritional value). The levels of these compounds are cultivar-dependent and vary with postharvest stages. The number of clusters of plum cultivars varied with both the clustering algorithm and postharvest stages. However, certain cultivars were consistently grouped regardless of the clustering method, indicating similar characteristics and responses to storage and shelf-life conditions. Similar consistent groupings were observed after cold storage and shelf life. Our findings also showed that K-means clustering is the most effective model for plum cultivar differentiation based on the Silhouette Score and Davies-Bouldin Index. This study enhances our understanding of how metabolites evolve over different postharvest stages and provides a robust framework for differentiating plum cultivars, which can aid in sorting and grading operations. The research offers actionable insights to improve postharvest handling and storage practices, which are critical for maintaining the nutritional quality of plums, an important fruit for human health.

Black soldier fly larvae (BSFL) are gaining attention as an alternative protein source in food and feed, promoting a circular economy, particularly in their dried form. In the literature, monitoring the behavior of larvae in a humid environment has not been established under different conditions of temperature and relative humidity as well as the quality of dried larvae is not always correlated to the conditions of drying. Therefore, this study comprehensively analyses the adsorption–desorption isotherms, drying kinetics, and subsequent quality changes of dried BSFL. Sorption isotherms were assessed at 40, 50, 60, and 70 °C using the gravimetric method, followed by mathematical modelling and determination of thermodynamic variables. Thin-layer drying kinetics were studied in a forced-air oven at the same temperatures, with a subsequent proximate analysis of the dried larvae. Among eight sorption isotherm models evaluated, the Peleg model provided the best fit, revealing type II sorption isotherms with an optimal storage water activity of 0.38. The Page model accurately described the drying kinetics of BSFL across all temperatures. Moisture diffusion coefficients ranged from 6.15 × 10^–11 to 2.63 × 10^–10 m²/s, with an activation energy of 48.66 kJ/mol. The dried larvae displayed impressive protein levels, varying from 39.67 ± 0.28% to 45.29 ± 0.07%, exceeding the minimum requirements set in the global insect production industry. Higher drying temperatures significantly impacted the proximate composition, reducing larvae quality. These findings underscore the potential of BSFL as a valuable protein source and enhance the understanding of their sorption behavior and quality attributes during drying. This study contributes to the optimization of drying conditions for improving the quality of BSFL as a sustainable protein alternative.

Plant volatile organic compounds are an abundant resource that can be used to explore natural gaseous fungicides. Recently, we found that (E)-2-heptenal, a green leaf volatile, could effectively inhibit the growth of Aspergillus flavus, showing promise for application as a biofumigant to prevent grain spoilage by A. flavus. In this study, the inhibitory effects of (E)-2-heptenal on A. flavus spore germination and mechanisms underlying these effects were investigated through morphological, biochemical, and transcriptomic analyses. The minimum inhibitory concentration and minimum fungicidal concentration of (E)-2-heptenal for spore germination of A. flavus were 4.0 and 6.0 µL/mL, respectively. (E)-2-heptenal treatment resulted in irregularly deformed, collapsed, and ruptured surface morphology of A. flavus spores, as well as destroyed cell wall integrity and reduced ergosterol content in A. flavus spores. Transcriptomic analysis revealed 4,312 differentially expressed genes in A. flavus spores exposed to (E)-2-heptenal, including 1,913 upregulated and 2,399 downregulated genes; these genes were mainly involved in ribosome biogenesis, cell cycle, linoleic acid metabolism, MAPK signaling, nucleoplasmic transport, meiosis, lipoic acid metabolism, DNA replication, and pyruvate metabolism pathways. (E)-2-heptenal can induce reactive oxygen species accumulation and mitochondrial dysfunction in A. flavus spores in a dose-dependent manner. Besides, DNA damage and autophagy was observed in (E)-2-heptenal-treated A. flavus spores with 4′,6-diamidino-2-phenylindole and monodansylcadaverine fluorescence staining. The findings of the present study provide insights into the underlying inhibitory mechanisms of (E)-2-heptenal on A. flavus spore germination.

Enzymatic browning induced by polyphenol oxidase (PPO) plays a significant role to quality reduction in fruit and vegetables. PPO inhibitors derived from natural products are gaining attention for their strong inhibitory abilities and low toxicity. This study aims to identify the component of phenolic-rich extract from Pueraria lobata root and evaluate their inhibitory capacity on PPO. The results showed that nine phenolics were identified by UPLC-QE-Orbitrap-MS method as PPO effective inhibitors based on their IC₅₀ values, in which kaempferol showed the strongest inhibitory effect. Among the inhibitors, kaempferol, daidzein, phloretin and luteolin with different inhibitory abilities were selected as representative flavonols, isoflavones, chalcones and flavonoids compounds to investigate the kinetics analysis and molecular interaction. Kaempferol and daidzein exhibited competitive inhibition on PPO, while phloretin and luteolin showed mixed-type and non-competitive inhibition, respectively. According to the fluorescence spectra results, these inhibitors were bound to PPO and quenching fluorescence, among which kaempferol showed the highest K_b value and accompanied by the blueshift. Molecular docking results indicated that the inhibitors interact with PPO primarily through hydrophobic interactions, van der Waals forces and hydrogen bonds, in which kaempferol showed the strongest binding ability with the lowest binding energy. This research provides a theoretical basis for the practical application of Pueraria lobata root extracts as natural PPO inhibitors in the food industry.

Printing foods in the desired shape with minimal additives and their stability after printing are the most important points for 3D food technology. In this study, the effects of water (5%, 10%, 15%, and 20%) and salt (0.5%, 1%, 1.5%, and 2%) on the printability of meat paste were evaluated to achieve improved textural and rheological properties. The printing parameters were examined at every stage, starting from the line thickness of the printed product, until the final 3D printed product was obtained. Accordingly, meat printability determined using different ingredient flow speed (3, 3.5, 4, 4.5, and 5), fill factor (1.2%, 1.3%, 1.4%, 1.5%, and 1.6%) and distance between layers (1.2, 1.4, and 1.6 mm). Salt addition increased the firmness and consistency of the samples, while the viscosity, storage modulus, and loss modulus decreased with the addition of water. Considering the line thickness and outer length, the most appropriate shape was obtained with 10% water and 1.5% salt. The optimal ingredient flow speed, fill factor, and distance between layers at a constant printing speed (2500 mm/min) were 3, 1.2%, and 1.4 mm, respectively. Four-layer-infilled 3D-printed samples maintained their initial shape after cooking, regardless of the cooking method. However, only baked products maintained their initial shapes among full-infilled samples. Although water and salt have different functions in meat, the use of the appropriate ratio is necessary for 3D-printed meat-based products to provide printability and post-production stability. To sum up optimum parameters and road map for printing meat and meat products including leftover meats and low-value by-products were revealed.