Transcriptome sequencing and metabolome analysis reveal the molecular mechanism of Salvia miltiorrhiza in response to drought stress.

Salvia miltiorrhiza is commonly used as a Chinese herbal medicine to treat different cardiovascular and cerebrovascular illnesses due to its active ingredients. Environmental conditions, especially drought stress, can affect the yield and quality of S. miltiorrhiza. However, moderate drought stress could improve the quality of S. miltiorrhiza without significantly reducing the yield, and the mechanism of this initial drought resistance is still unclear. In our study, transcriptome and metabolome analyses of S. miltiorrhiza under different drought treatment groups (CK, A, B, and C groups) were conducted to reveal the basis for its drought tolerance. We discovered that the leaves of S. miltiorrhiza under different drought treatment groups had no obvious shrinkage, and the malondialdehyde (MDA) contents as well as superoxide dismutase (SOD) and peroxidase (POD) activities dramatically increased, indicating that our drought treatment methods were moderate, and the leaves of S. miltiorrhiza began to initiate drought resistance. The morphology of root tissue had no significant change under different drought treatment groups, and the contents of four tanshinones significantly enhanced. In all, 5213, 6611, and 5241 differentially expressed genes (DEGs) were shared in the A, B, and C groups compared with the CK group, respectively. The results of KEGG and co-expression analysis showed that the DEGs involved in plant-pathogen interactions, the MAPK signaling pathway, phenylpropanoid biosynthesis, flavonoid biosynthesis, and plant hormone signal transduction responded to drought stress and were strongly correlated with tanshinone biosynthesis. Furthermore, the results of metabolism analysis indicated that 67, 72, and 92 differentially accumulated metabolites (DAMs), including fumarate, ferulic acid, xanthohumol, and phytocassanes, which were primarily involved in phenylpropanoid biosynthesis, flavonoid biosynthesis, and diterpenoid biosynthesis pathways, were detected in these groups. These discoveries provide valuable information on the molecular mechanisms by which S. miltiorrhiza responds to drought stress and will facilitate the development of drought-resistant and high-quality S. miltiorrhiza production.

First Report of Leaf Spot Disease on Lonicera japonica Caused by Nigrospora oryzae in China.

Lonicera japonica Thunb. is a traditional Chinese medicinal plant, which widely cultivated in China, Japan and Korea. From August to October in 2021 and 2022, severe leaf spots symptoms were observed on L. japonica in medicinal botanical garden of Shandong University of Traditional Chinese Medicine (36°55'89"N, 116°79'91"E), Jinan, Shandong Province, China. The disease incidence was above 80% in the 25 acre cultivation area. Early symptoms were small brown spots on the leaves. Then the number of small spots gradually increased and spread over the entire leaves. The small brown spots seldom merge together to form larger lesions. Leaves with typical symptoms were collected from twenty individual plants, and cut into small 5×5 mm fragments in the junction of infected and healthy tissues. The fragments were sterilized in 75% ethanol for 30 s and 1% NaClO for 60 s, rinsed three times in sterile water, and then placed on potato dextrose agar (PDA). After 3 days of incubation at 25°C, fungal plugs along the edge of the colony were cut and transferred to new PDA for purification. A total number of 23 colonies with similar morphological characteristics were obtained, and three representative strains (Lj14, Lj18 and Lj20) were selected for subsequent study. The colonies grew rapidly on PDA and covered the entire petri dish in 4 days. Colonies had abundant aerial hyphae, initially white, round, later turning gray and black. Conidia were oblate or nearly spherical, single-celled, black, and measured in size from 9.6 to 13.2 µm × 7.9 to 16.1 µm in diameter (n=150) (Figure S1). The observed characteristics were close to those of Nigrospora spp. ( Wang et al. 2017). The genomic DNA was extracted, and PCR amplification of the rDNA internal transcribed spacer (ITS), ß-tubulin gene (TUB), and translation elongation factor 1-alpha gene (TEF1) were completed by primers ITS1/ITS4, Bt2a/Bt2b and EF1-728F/EF1-986R (Carbone and Kohn, 1999). Sequences were deposited in GenBank (accession nos. OR936661, OR936662, OR936671 for ITS, OR947626, OR947627, OR947628 for TUB, and OR947629, OR947630, OR947631 for TEF1 sequences, respectively). BLAST analyses of ITS (OR936661), TUB(OR947626) and TEF1 (OR947629) sequences exhibited 100% (487 bp out of 487 bp), 99.48% (380 bp out of 382 bp), and 99.6% (248 bp out of 249 bp) similarity to the sequences of N. oryzae strains KoLRI_053384 (MZ855426), LC2991 (KY019496) and LC7307 (KY019409), respectively. Lj14, Lj18 and Lj20 formed a clade with N. oryzae LC6763 and LC2991 in phylogenetic tree (Figure S2). Based on morphological and molecular evidence, the pathogen was identified as N. oryzae (Berk. &Broome) Petch. To fulfill Koch's postulates, the pathogenicity was tested in vivo experiments. Thirty non-wounded healthy leaves of ten intact plants were inoculated with 10 µl spore suspension (106 spores/ml) of three strains, respectively. As negative control, thirty leaves of ten healthy plants were inoculated with sterile water. The inoculated plants were placed at 28°C in the growth chamber with high relative humidity. The pathogenicity tests were repeated three times. Distinct symptoms similar to that of natural conditions were observed on the leaves of inoculated plants after 4 to 7 days. The strain was reisolated from the lesions and identified as N. oryzae by morphological features and ITS sequence. The pathogen has been reported to cause leaf spot disease on tobacco (Wang et al. 2022) and asiatic dayflower (Qiu et al. 2022). To our knowledge, this is the first report of leaf spot caused by N. oryzae on Lonicera japonica in China. The research will be helpful for leaf spot disease control.

Colorimetric aptasensor for Listeria monocytogenes detection using dual functional Fe3O4@MIL-100(Fe) with magnetic separation and oxidase-like activities in food samples.

A novel colorimetric aptasensor assay based on the excellent magnetic responsiveness and oxidase-like activity of Fe3O4@MIL-100(Fe) was developed. Fe3O4@MIL-100(Fe) absorbed with aptamer and blocked by BSA served as capture probe for selective isolation and enrichment of Listeria monocytogenes one of the most common and dangerous foodborne pathogenic bacteria. The aptamer absorbed on Fe3O4@MIL-100(Fe) was further used as signal probe that specifically binds with target bacteria conjugation of capture probe for colorimetric detection of Listeria monocytogenes, taking advantages of its oxidase-like activity. The linear range of the detection of Listeria monocytogenes was from 102 to 107 CFU mL-1, with the limit of detection as low as 14 CFU mL-1. The approach also showed good feasibility for detection of Listeria monocytogenes in milk and meat samples. The spiked recoveries were in the range 81-114% with relative standard deviations ranging from 1.28 to 5.19%. Thus, this work provides an efficient, convenient, and practical tool for selective isolation and colorimetric detection of Listeria monocytogenes in food.

Effect of deacetylated konjac glucomannan on the 3D printing properties of minced pork.

BACKGROUND: The influences of deacetylated konjac glucomannan (DKGM) at different condition levels (0.0%, 0.5%, 1.0%, 1.5%, 2.0%) on the 3D printing feasibility, printing properties, and the final gel characteristics of minced pork were investigated. RESULTS: As the DKGM content increased, the printing accuracy and stability initially increased and then declined, and the printing stability and accuracy increased to their highest levels (98.16% and 98.85%) with a 1.5% addition of DKGM. Furthermore, the addition of DKGM significantly enhanced the texture of 3D-printed meat after heat treatments. When the DKGM content reached 1.5%, the hardness and springiness were 1.19 and 1.06 times higher than those of the control group. The results of low-field nuclear magnetic resonance and Raman spectra revealed that DKGM enhanced the amount of bound water in 3D-printed meat and encouraged changes in protein structure. After the addition of DKGM at 1.5%, the contents of bound water and ß-sheets were 7.67% and 12.89% higher than those of the control group, respectively, facilitating the development of a better gel network of minced meat during heating. CONCLUSION: The results indicate that a concentration of 1.5% DKGM is the ideal setting for obtaining the desired rheological properties and textural characteristics (printability) of 3D-printed minced meat products compared to other samples. In addition, the results showed that the addition of DKGM at 1.5% promotes the transition from α-helix to ß-folding of proteins during heating, which facilitates the formation of gels. The results of the study contribute to the application potential of minced meat in the field of 3D food printing. © 2024 Society of Chemical Industry.

Enhancement effect of carvacrol on yeast inactivation by mild pressure carbon dioxide.

Saccharomyces cerevisiae is one of the common spoilage microorganisms in fruit juices. This paper investigated the influences of carvacrol on S. cerevisiae inactivation by mild pressure carbon dioxide (MPCO2). The results demonstrated that carvacrol synergistically enhanced the antifungal activity against S. cerevisiae of MPCO2. With the increase of carvacrol concentration (20-160 µg/mL), CO2 pressure (1.5-3.5 MPa), process temperature (20-40 °C), and treatment time (15-60 min), the inactivation effect of carvacrol combined with MPCO2 on S. cerevisiae was gradually increased and significantly stronger than either single treatment. In the presence of carvacrol, MPCO2 severely disordered the plasma membrane of S. cerevisiae, including the increase of membrane permeability, and the loss of membrane potential and integrity. MPCO2 and carvacrol in combination also aggravated the mitochondrial depolarization of S. cerevisiae and reduced intracellular ATP and protein content. This study suggests the potential of carvacrol and pressurized CO2 as an alternative technology for food pasteurization.

Feasibility of atmospheric cold plasma for the elimination of food hazards: Recent advances and future trends.

In recent decades, food safety has emerged as a worldwide public health issue with economic and political implications. Pesticide residues, mycotoxins, allergens, and antinutritional factors are the primary concerns associated with food products due to their potential adverse health effects. Although various conventional processing methods (such as washing, peeling, and cooking) have been used to reduce or eliminate these hazards from agricultural food materials, the results obtained are not quite satisfactory. Recently, atmospheric cold plasma (ACP), an emerging low -temperature and green processing technology, has shown great potential for mitigating food hazards. However, detailed descriptions of the effects of ACP treatment on food hazards are still not available. Thus, the current review aims to highlight recent studies on the efficacy and application of ACP in the reduction or elimination of pesticide residues, mycotoxins, allergens, and antinutritional factors in various food products. The possible working mechanisms of ACP and its effect on food quality, and the toxicity of degradation products are emphatically discussed. In addition, multiple factors affecting the efficacy of ACP are summarized in detail. At the same time, the major technical challenges for practical application and future development prospects of this emerging technology are also highlighted.

Effect of konjac oligo-glucomannan on emulsifying properties of myofibrillar protein.

BACKGROUND: The high viscosity of konjac glumannan (KGM) limits its application in meat processing. In this work, the effects of konjac oligo-glucomannan (KOG), as a derivative of KGM, on the emulsifying properties of myofibrillar protein (MP) and the related mechanism were investigated. RESULTS: It was found that the addition of KOG had no significant effect on the secondary structure of MP, but altered the tertiary conformation of MP, resulting in exposure of tyrosine residues to polar microenvironments and decreased intrinsic fluorescence intensity. In addition, the addition of KOG increased the emulsifying activity of MP, resulting in decreased particle size and improved physical stability of the emulsion. The emulsifying activity of MP reached the maximum value when 1.0 wt% KOG was added. Moreover, the interfacial tension and interfacially adsorbed protein content of MP/KOG emulsions decreased with the increase in KOG concentration. CONCLUSION: These findings demonstrated that KOG mainly interacted with MP and changed the amphipathy of the KOG-MP at the oil-water interface, forming a stable interface film to improve the emulsifying properties of MP. © 2023 Society of Chemical Industry.

A review on recent advances in plasma-activated water for food safety: current applications and future trends.

Plasma-activated water (PAW), the water or solutions treated with atmospheric cold plasma, is an eco-friendly technique with minimal changes in food products, making it a befitting alternative to traditional disinfection methods. Due to its potential microbicidal properties, PAW has been receiving increasing attention for applications in the food, agricultural, and biomedical fields. In this article, we aimed at presenting an overview of recent studies on the generation methods, physicochemical properties, and antimicrobial activity of PAW, as well as its application in the food industry. Specific areas were well discussed including microbial decontamination of food products, reduction of pesticide residues, meat curing, sprouts production, and disinfection of food contact materials. In addition, the factors influencing PAW efficiency were also well illustrated in detail, such as discharge parameters, types and amounts of microorganisms, characteristics of the liquid solution and food products, and treatment time. Moreover, the strategies to improve the efficacy of PAW were also presented in combination with other technologies. Furthermore, the salient drawbacks of this technology were discussed and the important areas for future research were also highlighted. Overall, the present review provides important insights for the application of PAW in the food industry.

Hydrophobic microporous extraction on polyurethane sponges for convenient and sensitive analysis of organic molecules in water.

RATIONALE: Various solvent supports have been developed to overcome solvent instability during liquid-phase microextraction. The hydrophobic polyurethane sponge (PS) possesses numerous cross-linked internal microchannels and terminal micropores that can facilitate steady solvent storage capacity, high extraction efficiency, extractant loading, and recycling convenience. METHODS: In this study, an easy, convenient, and efficient PS-supported liquid-phase microextraction (PS-LPME) coupled with gas chromatography-mass spectrometry (GC-MS) method was developed for the trace analysis of different organic compounds in aqueous solutions. Different extraction solvents, PS dosages, stirring speeds, and extraction times were first investigated by extracting eight polycyclic aromatic hydrocarbons (PAHs: naphthalene, acenaphthylene, acenaphthene, fluorene, phenanthrene, anthracene, fluoranthene, and pyrene), and then applied for the analysis of triazines, amides, chloroacetamides, and organophosphorus compounds. RESULTS: High enrichment factors (approximately 208-439) were observed for the monitored PAHs. Good linearities, with determination coefficients (r2 ) greater than 0.9992, were achieved in the concentration range of 0.01-50 µg L-1 . Low limits of detection and quantification were found in the ranges of 0.3-3 ng L-1 and 1-10 ng L-1 , respectively. At three spiked concentrations (0.1, 1, and 10 µg L-1 ), good recoveries were obtained in the range of 91.6-118.5% with intra- and inter-day relative standard deviations of less than 6.4% and 11.7%, respectively. CONCLUSIONS: The developed PS-LPME method coupled with GC-MS was successfully applied in the analysis of different organic compounds in aqueous solutions and has shown great convenience and satisfactory enrichment performance in microextraction analysis.

Solvothermal synthesis of α-Fe2O3 polyhedrons and its application in an immunochromatographic strip test for the detection of foodborne pathogen Listeria monocytogenes.

The immunochromatographic strip test (ICST) is a powerful on-site detection technology due to its unique advantages of simplicity, rapidity, and readability by the naked eye. Here we illustrate the potential of α-Fe2O3 polyhedrons as a novel visual label, which exhibit advantages of high stability and economy, for the detection of Listeria monocytogenes (L. monocytogenes) as a model foodborne pathogen. A low-cost and simple one-step solvothermal approach was developed for the synthesis of α-Fe2O3 polyhedrons; the average diameter of the α-Fe2O3 polyhedrons is about 200 nm. The crystal structure and morphology of α-Fe2O3 polyhedrons were characterized by x-ray diffraction and transmission electron microscope. α-Fe2O3 polyhedrons were immunized with anti-L. monocytogenes antibody to prepare an antibody-colloidal α-Fe2O3 polyhedron ICST. Visual detection can be obtained directly by the naked eye within 10 min. The detection limit of L. monocytogenes by α-Fe2O3 polyhedron ICST assay was 3.8 × 106 and 5.6 × 106 CFU/ml of pure culture and artificially spiked orange juice drink sample, respectively. Results indicated that the antibody-colloidal α-Fe2O3 polyhedron ICST is a rapid, simple, and low-cost assay. This approach showed great potential in the application of foodborne pathogen detection concerning food safety.

Wi-CAS: A Contactless Method for Continuous Indoor Human Activity Sensing Using Wi-Fi Devices.

With the new coronavirus raging around the world, home isolation has become an effective way to interrupt the spread of the virus. Effective monitoring of people in home isolation has also become a pressing issue. However, the large number of isolated people and the privatized isolated spaces pose challenges for traditional sensing techniques. Ubiquitous Wi-Fi offers new ideas for sensing people indoors. Advantages such as low cost, wide deployment, and high privacy make indoor human activity sensing technology based on Wi-Fi signals increasingly used. Therefore, this paper proposes a contactless indoor person continuous activity sensing method based on Wi-Fi signal Wi-CAS. The method allows for the sensing of continuous movements of home isolated persons. Wi-CAS designs an ensemble classification method based on Hierarchical Clustering (HEC) for the classification of different actions, which effectively improves the action classification accuracy while reducing the processing time. We have conducted extensive experimental evaluations in real home environments. By recording the activities of different people throughout the day, Wi-CAS is very sensitive to unusual activities of people and also has a combined activity recognition rate of 94.3%. The experimental results show that our proposed method provides a low-cost and highly robust solution for supervising the activities of home isolates.

Effect of chickpea (Cicer arietinum L.) protein isolate on the heat-induced gelation properties of pork myofibrillar protein.

BACKGROUND: Heat-induced composite gels were prepared with 30 mg mL-1 pork myofibrillar protein (MP) and chickpea protein isolate (CPI) (0, 3, 6, 9, 12, and 15 g kg-1 ) in 0.6 mol L-1 NaCl, at pH 7.0. The gel strength, water-holding capacity, rheological properties, and microstructure of MP-CPI composite gels were investigated. RESULTS: Chickpea protein isolate improved (P < 0.05) gel strength and water-holding capacity of the MP composite gels. The rheological properties of MP-CPI composite gels were improved significantly by the addition of CPI. Meanwhile, the effects of CPI on the storage modulus of composite gels were positively correlated with the increased addition of CPI. Furthermore, according to low-field nuclear magnetic resonance (LF-NMR) results, the addition of CPI reduced the relaxation time of the composite gels and the relaxation peak area of free water, indicating that CPI could improve the water-holding capacity of MP-CPI composite gels. The microstructure of MP-CPI composite gels presented smaller and more uniform pores, which means that more water could be retained. CONCLUSION: The addition of chickpea protein isolate improved the gel strength, water-holding capacity, rheological properties, and microstructure of MP gels, indicating that CPI could be a potential protein additive to improve the microstructure, texture, and functional quality of meat products. © 2020 Society of Chemical Industry.

Effect of bamboo shoot dietary fiber on gel properties, microstructure and water distribution of pork meat batters.

OBJECTIVE: To develop healthier comminuted meat products to meet consumer demand, the gel properties, rheological properties, microstructure and water distribution of pork meat batters formulated with various amounts of bamboo shoot dietary fiber (BSDF) were investigated. METHODS: Different levels of BSDF (0% to 4%) were added to pork batters, and the pH, color, water-holding capacity, texture and rheological properties of pork batters were determined. Then, pork batters were analyzed for their microstructure and water distribution using scanning electron microscopy (SEM) and low-field nuclear magnetic resonance (LF-NMR). RESULTS: Compared with the control, BSDF addition into meat batters showed a significant reduction in L*-value and a significant increase in b*-value (p<0.05). BSDF addition of up to 4% reduced the pH value of pork batters by approximately 0.15 units; however, the cooking loss and expressible water loss decreased significantly (p<0.05) with the increased addition of BSDF. The hardness and gel strength were noticeably enhanced (p<0.05) as the content of BSDF increased. The rheological results showed that BSDF added into pork batters produced higher storage modulus (G') and loss modulus (G″) values. The SEM images suggested that the addition of BSDF could promote pork batters to form a more uniform and compact microstructure. The proportion of immobilized water increased significantly (p<0.05), while the population of free water was decreased (p<0.05), indicating that BSDF improved the water-holding capability of pork batters by decreasing the fraction of free water. CONCLUSION: BSDF could improve the gel properties, rheological properties and water distribution of pork meat batters and decrease the proportion of free water, suggesting that BSDF has great potential as an effective binder in comminuted meat products.

Preparation and characterization of Ca(II) cross-linking modified pectin microspheres for Pb(II) adsorption.

A novel adsorbent, composed of cross-linked de-esterified pectin microspheres, was prepared via cross-linking with Ca(II) and modification by de-esterified pectin, low-methoxyl pectin (LMP) and pectic acid (PA). Fourier transform infrared (FTIR), energy dispersive spectrometry (EDS), scanning electron microscopy (SEM) and atomic absorption spectroscopy (AAS) were applied too, exhibiting a successful fabrication, good adsorption ability, and well-defined surface microstructure beneficial to Pb(II) adsorption. The adsorption ability of pectin microspheres (PMs), low-methoxyl pectin microspheres (LMPMs) and pectic acid microspheres (PAMs) for Pb(II) in aqueous solution were explored. The maximum adsorption capacity of PMs, LMPMs and PAMs was 127 mg·g-1, 292 mg·g-1 and 325 mg·g-1 at pH 5.0 respectively, indicating a great improvement of LMPMs and PAMs in the adsorption ability for Pb(II) compared with PMs. Furthermore, the adsorption mechanism was proposed. The experimental data were well fitted with pseudo-second-order kinetic and Langmuir isotherm models. Five-cycle reusability tests demonstrated that microspheres could be used repeatedly. All the results confirmed that LMPMs and PAMs, which presented outstanding adsorption capability and reusability, could be a good candidate for wastewater purification.

Comparative study of thermal gelation properties and molecular forces of actomyosin extracted from normal and pale, soft and exudative-like chicken breast meat.

OBJECTIVE: The objectives of this study were to investigate the thermal gelation properties and molecular forces of actomyosin extracted from two classes of chicken breast meat qualities (normal and pale, soft and exudative [PSE]-like) during heating process to further improve the understanding of the variations of functional properties between normal and PSE-like chicken breast meat. METHODS: Actomyosin was extracted from normal and PSE-like chicken breast meat and the gel strength, water-holding capacity (WHC), protein loss, particle size and distribution, dynamic rheology and protein thermal stability were determined, then turbidity, active sulfhydryl group contents, hydrophobicity and molecular forces during thermal-induced gelling formation were comparatively studied. RESULTS: Sodium dodecyl sulphate-polyacrylamide gel electrophoresis showed that protein profiles of actomyosin extracted from normal and PSE-like meat were not significantly different (p>0.05). Compared with normal actomyosin, PSE-like actomyosin had lower gel strength, WHC, particle size, less protein content involved in thermal gelation forming (p<0.05), and reduced onset temperature (To), thermal transition temperature (Td), storage modulus (G') and loss modulus (G″). The turbidity, reactive sulfhydryl group of PSE-like actomyosin were higher when heated from 40°C to 60°C. Further heating to 80°C had lower transition from reactive sulfhydryl group into a disulfide bond and surface hydrophobicity. Molecular forces showed that hydrophobic interaction was the main force for heat-induced gel formation while both ionic and hydrogen bonds were different significantly between normal and PSE-like actomyosin (p<0.05). CONCLUSION: These changes in chemical groups and inter-molecular bonds affected protein-protein interaction and protein-water interaction and contributed to the inferior thermal gelation properties of PSE-like meat.

Inactivation of Pseudomonas deceptionensis CM2 on chicken breasts using plasma-activated water.

The aim of this study was to examine the effectiveness of plasma-activated water (PAW) for inactivating Pseudomonas deceptionensis CM2 on chicken breasts. Sterile distilled water (SDW) was activated by gliding arc discharge plasma for 60 s, which was defined as PAW60. The chicken breast samples inoculated P. deceptionensis CM2 were dipped in PAW60 or SDW for the indicated time intervals, respectively. After the treatment of PAW60 for 12 min, the population of P. deceptionensis CM2 on chicken breast was significantly reduced by 1.05 log10 CFU/g (p < 0.05), which was higher than that of SDW-treated samples for the same time intervals (p < 0.05). The L* value of chicken breasts were increased whereas a* and b* values were decreased following PAW60 treatment, while there was no significant differences in the values of a* and b* between PAW60- and SDW-treated samples for the same time intervals (p > 0.05). As compared with SDW, PAW60 caused no significant changes in the texture characteristics (e.g. hardness, springiness, cohesiveness and gumminess) and sensory properties (e.g. appearance, color, odor, texture, acceptability). Thus, PAW can be very effective to improve microbiological safety of chicken breasts with resulting slight changes to the sensory qualities. This synergistic treatment of PAW with other non-thermal technologies should be well investigated in order to improve inactivation efficacy of PAW.

Influences of cold atmospheric plasma on microbial safety, physicochemical and sensorial qualities of meat products.

Meat and meat products can be contaminated with pathogenic microorganisms, which cause serious health problems and economic loss. Recently, numerous novel non-thermal technologies have been developed to respond to growing consumer demand for high quality and safe meat products. Cold atmospheric plasma (CAP) is a novel and emerging non-thermal technology, showing great potential for applications in the food industry. This review presents recent advances on the developments and applications of CAP in meat products, including generation and microbial inactivation effects of CAP as well as its influences on physicochemical qualities and sensory attributes of meat products. Furthermore, the safety assessment of CAP-treated meat products and challenges in industrial application of CAP are also discussed.

The Effects of Assisted Freezing with Different Ultrasound Power Rates on the Quality and Flavor of Braised Beef.

This study investigated the effects of ultrasound-assisted immersion freezing (UIF) at different power rates (0, 200, 400, and 600 W) on the changes in beef quality and flavor after braising. The results demonstrated that UIF treatment at 400 W significantly reduced the juice loss (cooking loss decreased from 49.04% to 39.74%) and fat oxidation (TBARS value decreased from 0.32 mg/kg to 0.20 mg/kg) of braised beef. In addition, the tenderness (hardness value decreased from 5601.50 g to 2849.46 g) and color stability of braised beef were improved after UIF treatment. The flavor characteristics of braised beef were characterized using an electronic nose and an electronic tongue. The PCA analysis data showed that the cumulative contribution rates of the first and second principal components were 85% and 93.2%, respectively, with the first principal component accounting for a higher proportion. The UIF-400 W group had the highest concentration for the first principal component, and the differentiation was not significant compared to the control group. The total amino acid values of different power UIF treatment groups were improved compared to the AF treatment group, indicating that UIF can effectively reduce the losses caused by freezing. The results demonstrate that ultrasound-assisted freezing treatment is beneficial in enhancing the tenderness and flavor attributes of beef after braising, providing new insights into the processing of meat products with desirable quality characteristics.

Properties of Myofibrillar Protein in Frozen Pork Improved through pH-Shifting Treatments: The Impact of Magnetic Field.

The present study demonstrates the effects of pH-shifting treatments and magnetic field-assisted pH-shifting treatments on the properties of myofibrillar protein (MP) in frozen meat. The solubility results indicate that the pH-shifting treatments increased the solubility of MP from 16.8% to a maximum of 21.0% (pH 9). The values of surface hydrophobicity and protein particle size distribution indicate that the pH-shifting treatment effectively inhibited protein aggregation through electrostatic interactions. However, under higher pH conditions (pH 10, 11), the treatments assisted by the magnetic field increased the degree of aggregation. The total thiol content and SDS-PAGE results further suggest that the magnetic field-assisted pH-shifting treatment accelerated the formation of covalent bonds among MPs under the alkaline environment. The results of the Differential Scanning Calorimetry (DSC) and protein secondary structure analysis indicate that the magnetic field promoted the unfolding of protein structures in an alkaline environment, markedly reducing the effective pH levels of pH-shifting. Electron paramagnetic resonance (EPR) data indicate that the phenomenon might be associated with the increased concentration of free radicals caused by the magnetic field treatment. In summary, the application of magnetic field-assisted pH-shifting treatments could emerge as a potent and promising strategy to improve the protein properties in frozen meat.

Europium functionalized porphyrin-based metal-organic framework heterostructure and hydrogel for visual ratiometric fluorescence sensing of sulfonamides in foods.

Protecting human health and ensuring food security require the swift and accurate detection of sulfonamides (SAs) residues in foods. Herein, we proposed an Eu-postfunctionalized bimetallic porphyrin metal-organic framework (PCN-221(Zr/Ce)@Eu-DPA-H4btec) synthesized solvothermally for fluorescence sensing. The PCN-221(Zr/Ce)@Eu-DPA-H4btec fluorescent sensor demonstrated excellent stability and high selectivity to SAs, and the detection limits of sulfamethazine (SM2), sulfamerazine (SMR), and sulfamethoxydiazine (SMD) were as low as 56 nmol/L, 45 nmol/L, and 56 nmol/L, respectively. The PCN-221(Zr/Ce)@Eu-DPA-H4btec fluorescent sensor was successfully applied for the detection of SM2, SMR, and SMD in real pork and milk samples, with satisfactory recoveries (81.2-118.3%) and high precisions (RSDs <8.2, n = 3). Combining the optical properties of the nanohybrids, PCN-221(Zr/Ce)@Eu-DPA-H4btec integrated fluorescent hydrogels were innovatively prepared for visual sensing of SM2, SMR, and SMD. This study provides an uncomplicated and sensitive method for SAs detection in food matrices.