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1.
Int J Food Microbiol ; 422: 110814, 2024 Sep 16.
Artículo en Inglés | MEDLINE | ID: mdl-38972103

RESUMEN

Ohmic heating (OH), an emerging food processing technology employed in the food processing industry, raises potential food safety concerns due to the recovery of sublethally injured pathogens such as Staphylococcus aureus (S. aureus). In the present study, sensitivity to various stress conditions and the changes in cellular-related factors of OH-injured S. aureus during repair were investigated. The results indicated that liquid media differences (nutrient broth (NB), phosphate-buffered saline (PBS), milk, and cucumber juice) affected the recovery process of injured cells. Nutrient enrichment determines the bacterial repair rate, and the rates of repair for these media were milk > NB > cucumber juice > PBS. The sensitivity of injured cells to various stressors, including different acids, temperature, nisin, simulated gastric fluid, and bile salt, increased during the injury phase and subsequently diminished upon repair. Additionally, the intracellular ATP content, enzyme activities (Na+/K+-ATPase, Ca2+/Mg2+-ATPase, and T-ATPase) and ion concentrations (Mg2+, K+, and Ca2+) gradually increased during repair. After 5 h of repair, the intracellular substances content of cell's was significantly higher than that of the injured bacteria without repair, while some indicators (e.g., Na+/K+-ATPase, K+, and Ca2+) were not restored to the untreated level. The results of this study indicated that OH-injured S. aureus exhibited strengthened resistance post-recovery, potentially due to the restoration of cellular structures. These findings have implications for optimizing food storage conditions and advancing OH processes in the food industry.


Asunto(s)
Manipulación de Alimentos , Calor , Staphylococcus aureus , Manipulación de Alimentos/métodos , Microbiología de Alimentos , Estrés Fisiológico , Adenosina Trifosfato/metabolismo
2.
Int J Food Microbiol ; 421: 110784, 2024 Aug 16.
Artículo en Inglés | MEDLINE | ID: mdl-38897047

RESUMEN

Bacillus cereus spores pose a significant concern during food processing due to their high resistance to environmental stress. Ohmic heating (OH) is an emerging and alternative heating technology with potential for inactivating such spores. This study evaluated the inactivation effects and the biological property changes of Bacillus cereus spores during OH treatments. OH effectively inactivated spores in milk, orange juice, broth, rice soup, and buffer solution in less time than oil bath heating (OB). A decrease in NaCl content improved spore inactivation at the same temperature. Spores were more sensitive to acid at 80-85 °C with OH treatment. Furthermore, OH at 10 V/cm and 50 Hz could reduce the spore resistance and inhibit an increase in spore hydrophobicity and spore aggregation. Both heating methods resulted in significant dipicolinic acid (DPA) leakage and damage to the cortex and inner membranes of the spores. However, OH at 10 V/cm and 50 Hz had the lowest DPA leakage and inflicted the least damage to the inner membrane. The damage to the spore's inner membrane was considered the primary reason for inactivation by OB and OH treatments. Still, OH at 10 V/cm and 50 Hz might also block the germination or outgrowth of treated spores or cause damage to the spore core.


Asunto(s)
Bacillus cereus , Calor , Esporas Bacterianas , Esporas Bacterianas/crecimiento & desarrollo , Esporas Bacterianas/efectos de la radiación , Bacillus cereus/crecimiento & desarrollo , Microbiología de Alimentos , Viabilidad Microbiana , Ácidos Picolínicos/farmacología , Manipulación de Alimentos/métodos
3.
J Agric Food Chem ; 72(19): 11111-11123, 2024 May 15.
Artículo en Inglés | MEDLINE | ID: mdl-38710026

RESUMEN

Apoptotic cells may release specific metabolites to act as messengers during the apoptotic process. This study represents the first attempt to identify potential apoptotic metabolites in postmortem muscle. Ninety potential apoptotic metabolites in beef were selected and analyzed through targeted metabolomics, with 84 of them exhibiting significant differences over the postmortem time. Following the addition of the mitochondria-targeted antiapoptotic agent mitoquinone to postmortem muscle, metabolomic analysis revealed that 73 apoptotic metabolites still underwent significant changes, even against the backdrop of altered apoptosis. Of these 73 apoptotic metabolites, 54 exhibited similar trends at various treatment times with adding mitoquinone, including lipids (6), amino acids (27), nucleosides (11), and carbohydrate and energy metabolism (10). Mitoquinone significantly reduced the levels of most apoptotic metabolites, and inhibition of apoptosis resulted in a significant decrease in the levels of numerous apoptotic metabolites. Consequently, these apoptotic metabolites are considered complementary to apoptosis in postmortem muscle, with their increased levels potentially promoting apoptosis. Noteworthy apoptotic metabolites, such as glycerol 3-phosphate, serine, AMP, ATP, GMP, and creatine, were identified as active signaling molecules that attract and recruit phagocytes during apoptosis, assisting in recognizing apoptotic cells by phagocytes. This study provides, for the first time, insights into potential apoptotic metabolites in postmortem muscle, contributing to a better understanding of meat biochemistry.


Asunto(s)
Apoptosis , Metabolómica , Músculo Esquelético , Animales , Bovinos/metabolismo , Músculo Esquelético/metabolismo , Músculo Esquelético/química , Carne Roja/análisis , Aminoácidos/metabolismo
4.
Int J Food Microbiol ; 410: 110483, 2024 Jan 30.
Artículo en Inglés | MEDLINE | ID: mdl-37995495

RESUMEN

Ohmic heating (OH), an innovative heating technology, presents potential applications in the pasteurization of liquid foods. Therefore, the study was conducted to evaluate the effect of OH at various voltage gradients (10 V/cm, 12.5 V/cm, and 15 V/cm) and water bath (WB) on microbial inactivation, physicochemical and sensory properties and microbial flora of pasteurized milk. Results indicated that OH with higher voltage could effectively inactivate microorganisms in milk, requiring less heating time and energy. Moreover, OH treatment at higher voltages could decelerate lipid oxidation and better maintain the sensory quality and essential amino acids content of milk. Additionally, all treatments significantly altered the microbial community, and during storage, the microbial community in milk treated with 10 V/cm and 12.5 V/cm OH remained relatively stable. OH treatments with voltage gradients exceeding 12.5 V/cm could effectively inactive microorganisms and maintain the quality attributes of milk.


Asunto(s)
Calefacción , Leche , Animales , Leche/química , Calor , Pasteurización/métodos , Viabilidad Microbiana
5.
Sci Total Environ ; 912: 168905, 2024 Feb 20.
Artículo en Inglés | MEDLINE | ID: mdl-38016549

RESUMEN

In traditional CRISPR-based biosensors, the cleavage-induced signal generation is insufficient because only a signals is generated at a CRISPR-induced cleavage. Herein, we developed an improved CRISPR/Cas12a-based biosensor with an enlarged signal generation which integrated the hybridization chain reaction (HCR) and low-background Förster Resonance Energy Transfer (FRET) signal output mode. The HCR with nucleic acid self-assembly capability was used as a signal carrier to load more signaling molecules. To get the best signal amplification, three different fluorescence signal output modes (fluorescence recovery, FRET and low-background FRET) generated by two fluoresceins, FAM and Cy5, were fully investigated and compared. The results indicated that the low-background FRET signal output mode with the strictest signal generation conditions yielded the highest signal-to-noise ratio (S/N) (19.17) and the most obvious fluorescence color change (from red to yellow). In optimal conditions, the proposed biosensor was successfully applied for Salmonella Typhimurium (S. Typhimurium) detection with 6 h (including 4 h for sample pre-treatment) from the initial target processing to the final detection result. The qualitative sensitivity, reliant on color changes, was 103 CFU/mL. The quantitative sensitivity, calculated by the fluorescence value, were 1.62 × 101 CFU/mL, 3.72 × 102 CFU/mL, and 8.71 × 102 CFU/mL in buffer solution, S. Typhimurium-spiked milk samples, and S.Typhimurium-spiked chicken samples, respectively. The excellent detection performance of the proposed biosensor endowed its great application potential in food and environment safety monitoring.


Asunto(s)
Técnicas Biosensibles , Salmonella typhimurium , Técnicas Biosensibles/métodos , Hibridación de Ácido Nucleico , Fluoresceínas , Hibridación Genética
6.
Food Res Int ; 173(Pt 1): 113204, 2023 11.
Artículo en Inglés | MEDLINE | ID: mdl-37803533

RESUMEN

As an emerging food processing technology, cold atmospheric plasma (CAP) has attracted great attention in the field of microbial inactivation. Although CAP has been proven to effectively inactivate a variety of foodborne pathogens, there is less research on the inactivation of Bacillus cereus, and the exact inactivation mechanism is still unclear. Elucidating the inactivation mechanism will help to develop and optimize this sterilization method, with the prospective application in industrialized food production. This study aims to explore the bactericidal efficacy difference between air and nitrogen CAP on B. cereus, a typical Gram-positive bacterium, and reveals the inactivation mechanism of CAP at the cellular and molecular level, by observing the change of the cell membrane, cell morphological damage, intracellular antioxidant enzyme activity and cellular biomacromolecules changes. The results showed that both air CAP and nitrogen CAP could effectively inactivate B. cereus, which was due to the reactive oxygen and nitrogen species (RONS) generated by the plasma causing bacterial death. The damage pathways of CAP on Gram-positive bacteria could be explained by disrupting the bacterial cell membrane and cell morphology, disturbing the intracellular redox homeostasis, and destroying biomacromolecules in the cells. The differences in active species generated by the plasma were the main reason for the different bactericidal efficiencies of air CAP and nitrogen CAP, where air CAP producing RONS with stronger oxidative capacity in a shorter time. This study indicates that air CAP is an effective, inexpensive and green technology for B. cereus inactivation, providing a basis for industrial application in food processing.


Asunto(s)
Bacillus cereus , Gases em Plasma , Gases em Plasma/farmacología , Nitrógeno , Antibacterianos/farmacología , Bacterias Grampositivas , Especies Reactivas de Oxígeno
7.
Crit Rev Food Sci Nutr ; : 1-24, 2023 Jul 15.
Artículo en Inglés | MEDLINE | ID: mdl-37452658

RESUMEN

Meat quality holds significant importance for both consumers and meat producers. Various factors influence meat quality, and among them, mitochondria play a crucial role. Recent studies have indicated that mitochondria can sustain their functions and viability for a certain duration in postmortem muscles. Consequently, mitochondria have an impact on oxygen consumption, energy metabolism, and apoptotic processes, which in turn affect myoglobin levels, oxidative stress, meat tenderness, fat oxidation, and protein oxidation. Ultimately, these factors influence the color, tenderness, and flavor of meat. However, there is a dearth of comprehensive summaries addressing the effects of mitochondria on postmortem muscle physiology and meat quality. Therefore, this review aims to describe the characteristics of muscle mitochondria and their potential influence on muscle. Additionally, a suitable method for isolating mitochondria is presented. Lastly, the review emphasizes the regulation of oxygen consumption, energy metabolism, and apoptosis by postmortem muscle mitochondria, and provides an overview of relevant research and recent advancements. The ultimate objective of this review is to elucidate the underlying mechanisms through which mitochondria impact meat quality.

8.
Food Res Int ; 169: 112867, 2023 07.
Artículo en Inglés | MEDLINE | ID: mdl-37254316

RESUMEN

Bacillus cereus spore is one of the most easily contaminated bacterial spores in low-water activity foods such as black pepper. Atmospheric-pressure plasma jet (APPJ) has emerged as an emerging and promising method for microbial inactivation in food processing. This study aimed to investigate the efficacy of APPJ in inactivating spores under various treatment parameters and to examine the resulting alterations in spore structures and internal membrane properties. Meanwhile, the practical application of APPJ for spore inactivation in black pepper was also evaluated. The results indicated that air-APPJ had superior spore inactivation capability compared to N2 and O2-APPJ. After 20 min of APPJ treatment (50 L/min, 800 W, and 10 cm), the reduction in spore count (>2 log CFU/g) was significantly greater than that achieved by heat treatment (80℃). The damage of inner membranes was considered as the major reason of the dried spore inactivation by APPJ treatment. Moreover, it achieved a reduction in spore count of > 1 log CFU/g on inoculated black pepper without significantly affecting its color and flavor. Although the antioxidant activity of black pepper was slightly reduced, the overall quality of the product was not considerably affected by plasma treatment. This study concluded that APPJ is an effective technique for spore inactivation, offering promising potential for application in the decontamination of low-water activity foods.


Asunto(s)
Bacillus cereus , Agua , Bacillus cereus/fisiología , Recuento de Colonia Microbiana , Esporas Bacterianas , Presión Atmosférica
9.
J Food Sci ; 88(6): 2286-2300, 2023 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-37092657

RESUMEN

The purpose of this study was to prepare an essential oil nanoemulsion and apply it to meat products to achieve antimicrobial effect. The nanoemulsion of lemon essential oil was produced by high power ultrasonication. The influences of ultrasonic power, ultrasonic time, and mass ratio of sodium caseinate to essential oil on the particle size were examined. The optimal conditions for preparing nanoemulsion were ultrasonic power 327 W, ultrasonic time 18 min, and sodium caseinate to essential oil mass ratio 4.23:1. Lower temperature was more conducive to the preservation of nanoemulsion. Compared to control and essential oil group, the nanoemulsion could decrease the total volatile basic nitrogen content and total bacterial colony in pork patties. When applied to pork patties, the nanoemulsion decreased the microbial diversity and inhibited the growth of a variety of microorganisms such as Bacillus, extending the storage time of pork patties. This study developed a novel and workable nanoemulsion for inhibiting bacteria of meat products.


Asunto(s)
Microbiota , Aceites Volátiles , Carne de Cerdo , Carne Roja , Animales , Porcinos , Aceites Volátiles/farmacología , Caseínas
10.
Int J Biol Macromol ; 239: 124299, 2023 Jun 01.
Artículo en Inglés | MEDLINE | ID: mdl-37011742

RESUMEN

The effects of ethylcellulose (EC) concentration (6-12 %) and types of vegetable oil (sunflower, peanut, corn, and flaxseed oils) on the color, hardness, oil loss, lipid oxidation, and rheology property of oleogels were investigated in this study. Peanut oil (PO) oleogel was selected to replace pork fat partially in Harbin red sausage. Meanwhile, the fatty acid profile, texture, and sensory attributes of the reformulated sausages were analyzed. Oleogels formulated with higher EC concentration had higher brightness and hardness, a higher degree of lipid oxidation, and greater storage (G') and loss (G'') moduli. Oleogels formulated with PO had lower oil loss, flaxseed oil oleogel had higher hardness. Corn oil and PO oleogels had a lower level of lipid oxidation. The texture, lipid oxidation, and sensory attributes of the reformulated sausages, in which 10-30 % pork fat was replaced with PO oleogel, did not significantly differ from those without oleogel replacement. Meanwhile, the reformulated sausages had a healthier fatty acids profile and higher nutritional value.


Asunto(s)
Productos de la Carne , Aceites de Plantas , Compuestos Orgánicos , Ácidos Grasos , Productos de la Carne/análisis , Aceite de Cacahuete
11.
Food Res Int ; 165: 112536, 2023 03.
Artículo en Inglés | MEDLINE | ID: mdl-36869540

RESUMEN

Sublethally injured state has been recognized as a survival strategy for microorganisms suffering from stressful environments. Injured cells fail to grow on selective media but can normally grow on nonselective media. Numerous microorganism species can form sublethal injury in various food matrices during processing and preservation with different techniques. Injury rate was commonly used to evaluate sublethal injury, but mathematical models for the quantification and interpretation of sublethally injured microbial cells still require further study. Injured cells can repair themselves and regain viability on selective media under favorable conditions when stress is removed. Conventional culture methods might underestimate microbial counts or present a false negative result due to the presence of injured cells. Although the structural and functional components may be affected, the injured cells pose a great threat to food safety. This work comprehensively reviewed the quantification, formation, detection, resuscitation and adaption of sublethally injured microbial cells. Food processing techniques, microbial species, strains and food matrix all significantly affect the formation of sublethally injured cells. Culture-based methods, molecular biological methods, fluorescent staining and infrared spectroscopy have been developed to detect the injured cells. Cell membrane is often repaired first during resuscitation of injured cells, meanwhile, temperature, pH, media and additives remarkably influence the resuscitation. The adaption of injured cells negatively affects the microbial inactivation during food processing.


Asunto(s)
Preservación Biológica , Resucitación , Membrana Celular , Ansiedad , Manipulación de Alimentos
12.
Int J Food Microbiol ; 390: 110125, 2023 Apr 02.
Artículo en Inglés | MEDLINE | ID: mdl-36774686

RESUMEN

The inactivation effects and mechanism of ohmic heating (OH) on Bacillus cereus ATCC 11778 were investigated in this study, conventional heating (CH) was also carried out and served as control. All OH treatments (10 V/cm 50 Hz, 10 V/cm 500 Hz, 5 V/cm 50 Hz and 5 V/cm 500 Hz) could achieve a comparable inactivation effect with CH, while OH treatments significantly shortened the processing time. OH treated cells exhibited significantly higher leakage of metal ions (Mg2+ and K+) and biomacromolecules (nucleic acids and proteins) than those treated with CH when bacterial suspensions were heated to the same temperature. Moreover, OH treatment caused more damage on membrane structure, greatly decreased the cell membrane potential and endogenous enzyme activity than that of CH. The results of this study indicated that OH is more efficient in the inactivation of bacteria.


Asunto(s)
Bacillus cereus , Calefacción , Calor , Temperatura
13.
Meat Sci ; 198: 109092, 2023 Apr.
Artículo en Inglés | MEDLINE | ID: mdl-36603399

RESUMEN

This study was conducted to study muscle fiber characteristics and apoptotic factor differences within 24 h postmortem of bovine longissimus lumborum (LL) and psoas major (PM). Compared to LL, PM had a higher proportion of type I fibers and lower proportion of type II fibers. PM also had higher ROS levels. For bcl-2 family proteins, anti-apoptotic BCL-2 level was lower and pro-apoptotic BAX level was higher in PM. For caspases, at 1 h postmortem, gene and protein expression level of caspase-3 and caspase-9 was higher in PM than that of LL. The levels of DNA damage apoptotic factors ABL1, AIF and ENDOG was higher in PM than in LL. The results suggested that apoptotic gene and protein expression were different in muscles with different fiber type composition. These findings provided insights into muscle fiber and apoptotic factor differences during early postmortem in bovine PM and LL.


Asunto(s)
Músculo Esquelético , Carne Roja , Bovinos , Animales , Músculo Esquelético/metabolismo , Carne Roja/análisis , Fibras Musculares Esqueléticas , Músculos Psoas , Color , Proteínas Proto-Oncogénicas c-bcl-2/metabolismo
14.
Meat Sci ; 195: 109013, 2023 Jan.
Artículo en Inglés | MEDLINE | ID: mdl-36334513

RESUMEN

This study investigated changes in mitochondrial lipid molecules and their potential associations with Longissimus lumborum (LL) and Psoas major (PM) quality during storage. A total of 1610 lipid species that matched with 36 lipid classes were identified from isolated mitochondria. PM had more key lipid molecules at storage d-1 including diacylglycerol and triacylglycerol (may play roles in membrane stability), phosphatidylethanolamine, acyl carnitine and cardiolipin (involved in energy metabolism), and cardiolipin and phosphatidylserine (important factors in apoptosis). Correspondingly, with extended storage time, mitochondrial structure, cytochrome c and reactive oxygen species (ROS) were changed, and muscle oxidation intensified. These changes have close associations with shear force and water holding capacity (WHC). Compared with LL, PM had higher content of lipid classes, more mitochondrial ROS, greater muscle oxidation, and lower shear force and WHC. These findings provided new insights into the effects of lipidome on mitochondrial structure, ROS and cytochrome c, and their potential associations with beef quality.


Asunto(s)
Citocromos c , Músculo Esquelético , Animales , Bovinos , Citocromos c/análisis , Especies Reactivas de Oxígeno/metabolismo , Músculo Esquelético/química , Color , Cardiolipinas/análisis , Cardiolipinas/metabolismo , Mitocondrias/metabolismo , Músculos Psoas/metabolismo
15.
Biosens Bioelectron ; 219: 114823, 2023 Jan 01.
Artículo en Inglés | MEDLINE | ID: mdl-36308834

RESUMEN

CRISPR/Cas-based biosensors were typically used for nucleic-acid targets detection and complex DNA extraction and amplification procedures were usually inevitable. Here, we report a CRISPR/Cas12a-mediated, DNA extraction and amplification-free, highly direct and rapid biosensor (abbreviated as "CATCHER") for Salmonella Typhimurium (S. Typhimurium) with a simple (3 steps) and fast (∼2 h) sensing workflow. Magnetic nanoparticle immobilized anti-S. Typhimurium antibody was worked as capture probe to capture the target and provide movable reaction interface. Colloidal gold labeled with anti-S. Typhimurium antibody and DNase I was used as detection probe to bridge the input target and output signal. First, in the presence of S. Typhimurium, an immuno-sandwich structure was formed. Second, DNase I in sandwich structure degraded the valid, complete activator DNA to invalid DNA fragments which can't trigger the trans-cleavage activity of Cas12a. Finally, the integrity of reporter DNA was preserved presenting a low fluorescence signal. Conversely, in the absence of S. Typhimurium, strong fluorescence recovery appeared owing to the cutting of reporter by activated Cas12a. Significantly, the proposed "CATCHER" showed satisfactory detection performance for S. Typhimurium with the limit of detection (LOD) of 7.9 × 101 CFU/mL in 0.01 M PBS and 6.31 × 103 CFU/mL in spiked chicken samples, providing a general platform for non-nucleic acid targets.


Asunto(s)
Técnicas Biosensibles , Ácidos Nucleicos , Salmonella typhimurium/genética , Sistemas CRISPR-Cas/genética , Anticuerpos , Desoxirribonucleasa I
16.
Food Res Int ; 162(Pt A): 111934, 2022 12.
Artículo en Inglés | MEDLINE | ID: mdl-36461192

RESUMEN

Cold atmospheric plasma, featured as a non-thermal food processing technology has gained prominent attention for its practical application. The demand for chilled chicken has increased rapidly due to its nutritious value. However, chilled chicken often suffers from a short shelf life due to its susceptibility to spoilage. In this study, air- and nitrogen plasma were applied to investigate microbial inactivation effects and shelf-life extension of chilled chicken. Meanwhile, the microbial diversity of chicken breasts after air and nitrogen-CAP treatment and at the end of shelf-life was analyzed. Results illustrated that the inactivation effects of air plasma were more potent than that of nitrogen plasma, while nitrogen plasma could better maintain the sensory properties. Also, further investigation illustrated that air- and nitrogen-CAP could change the microbial community significantly. Both treatment time and working gases were essential experimental parameters that affected the microbial community composition.


Asunto(s)
Gases em Plasma , Animales , Pollos , Empleo , Gases , Nitrógeno
17.
Food Res Int ; 160: 111720, 2022 10.
Artículo en Inglés | MEDLINE | ID: mdl-36076413

RESUMEN

As a novel microbe inactivation strategy, cold atmospheric plasma (CAP) technology has attracted great attractions in the past two decades. This study demonstrated that the CAP treatment was a robust inactivation approach for P. aeruginosa. Air and nitrogen-CAP achieved 100 % inactivation efficiency in 5 and 9 min, respectively. Furthermore, the inactivation mechanisms were explained by measuring several physicochemical indexes, including the characteristics of bacterial suspension, cell membrane integrity, cell viability, and the concentration of intracellular substances. The possible inactivation mechanisms might be that the RONS generated by air and nitrogen attacked the cell envelope, resulted in the leakage of intracellular substances; meanwhile, RONS also destroyed the intracellular anti-oxidative system, accelerated the oxidative stress and disrupted the intracellular redox homeostasis, subsequently the death of the cells. Moreover, the inactivation application in chicken breasts proved CAP could be a novel sanitizing process in practical industries.


Asunto(s)
Gases em Plasma , Animales , Pollos , Viabilidad Microbiana , Nitrógeno , Gases em Plasma/farmacología , Pseudomonas aeruginosa
18.
Foods ; 11(14)2022 Jul 17.
Artículo en Inglés | MEDLINE | ID: mdl-35885362

RESUMEN

This study evaluated the effects of three polysaccharides, xanthan gum (XG), kappa-carrageenan (CA), and guar gum (GG), on the foaming and emulsifying properties of egg white liquid (EWL) and explored the intermolecular interactions and aggregation states in the initial polysaccharide−EWL complex. The results showed that the addition of XG and GG significantly improved the foaming stability of EWL on the one hand, from 66% to 78% and 69%, respectively (p < 0.05). On the other hand, the addition of XG and GG significantly improved the foam uniformity and density, and the average foam area decreased from 0.127 to 0.052 and 0.022 mm2, respectively (p < 0.05). The addition of XG and CA significantly improved the emulsification activity index (from 13.32 to 14.58 and 14.36 m2/mg, respectively, p < 0.05) and the emulsion stability index (from 50.89 to 53.62 and 52.18 min, respectively, p < 0.05), as well as the interfacial protein adsorption at the oil−water interface; it also reduced the creaming index. However, GG negatively affected these indicators. Furthermore, the electrostatic and hydrophobic interactions among molecules in EWL due to XG and the electrostatic, hydrogen bonding, and hydrophobic interactions among molecules in EWL due to CA ultimately led to the irregular aggregation of egg white proteins. Hydrophobic interactions and disulfide bonds between molecules in EWL−containing GG formed filamentous aggregations of egg white proteins. This work reveals that molecules in the polysaccharide−egg white complexes aggregate by interaction forces, which in turn have different effects on the foaming and emulsifying properties of egg white proteins.

19.
J Agric Food Chem ; 70(26): 8064-8074, 2022 Jul 06.
Artículo en Inglés | MEDLINE | ID: mdl-35709527

RESUMEN

Lipid molecules are important participants in mitochondria-mediated apoptosis. This study explored the effect of mitochondrial lipids on mitochondria-mediated apoptosis, mitochondrial reactive oxygen species (ROS) production, and muscle oxidation of beef longissimus lumborum (LL, n = 6) and psoas major (PM, n = 6) during 24 h postmortem. A total of 432 lipid species matched with 21 lipid classes were identified. Remarkably, at 12 h postmortem, the levels of cardiolipin and phosphatidylserine in PM and ceramide, cardiolipin, phosphatidylserine, and sphingosine in LL increased significantly compared with 1 h postmortem, indicating that mitochondria-mediated apoptosis in beef muscle was accelerated during early postmortem. Moreover, PM had higher levels of cardiolipin and phosphatidylserine than LL, also suggesting a higher degree of apoptosis in PM during postmortem. Lipid molecules may assist the production of mitochondrial ROS and decrease the mitochondrial membrane potential (MMP) during postmortem apoptosis, resulting in muscle oxidation and the damage of antioxidant system. Notably, compared with LL, PM had higher abundance of apoptosis-related lipid molecules, a higher amount of ROS, faster diminishment in MMP, and then a higher degree of apoptosis. These findings provided new insights into the apoptosis and muscle biochemistry in beef during early postmortem.


Asunto(s)
Cardiolipinas , Lipidómica , Animales , Apoptosis , Cardiolipinas/análisis , Cardiolipinas/metabolismo , Bovinos , Humanos , Mitocondrias , Músculo Esquelético/metabolismo , Fosfatidilserinas/metabolismo , Especies Reactivas de Oxígeno/metabolismo
20.
J Photochem Photobiol B ; 231: 112450, 2022 Jun.
Artículo en Inglés | MEDLINE | ID: mdl-35500384

RESUMEN

Plasmonic nanomaterials of gold and silver have been reported to have antibacterial effect. In this study, three gold nanomaterials (NMs) of different aspect rations (Gold nanospheres (AuNSs, aspect ratio 1), and two gold nanorods (AuNRs636, aspect ratio 2.79; AuNRs772, aspect ratio 3.42)) and silver nanoparticles (AgNPs) were synthesized, characterized and the effect of incandescent light on their antibacterial properties were examined. Bacterial inactivation during photoinactivation of nanomaterials and antibacterial mechanisms (biotic ROS, membrane potential, membrane damage) were investigated using Escherichia coli ATCC 25922, Staphylococcus aureus ATCC 25923, Salmonella enterica serovar Typhimurium, and methicillin-resistant S. aureus. The results indicated that AuNSs had no antibacterial activity in the tested concentration (0.49-250 µg/mL), while AuNR636 and AuNRs772 showed significant bactericidal effect on all tested bacteria. Notably, AuNRs636 presented higher antibacterial effect than AuNRs772, which could result from higher surface reactivity of AuNRs636 owing to higher dangling bonds. Further studies showed that AuNRs but not AuNSs generated hydroxyl radicals (·OH) (photodynamic effect) and photothermal effect when exposed to incandescent light. The combined photodynamic and photothermal effect resulted in bacterial inactivation through cell membrane damage, lowering of cell membrane potential and DNA degradation. In summary, this investigation showed that Au NRs but not Au NSs exhibit photodynamic and photothermal effects suggesting the potential of fabricating material surfaces with Au NRs for photoactivated bacterial inactivation.


Asunto(s)
Nanopartículas del Metal , Staphylococcus aureus Resistente a Meticilina , Nanosferas , Nanotubos , Antibacterianos/química , Antibacterianos/farmacología , Bacterias , Escherichia coli , Nanopartículas del Metal/química , Nanopartículas del Metal/toxicidad , Nanotubos/química , Plata/química
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