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1.
Cancers (Basel) ; 13(6)2021 Mar 23.
Artigo em Inglês | MEDLINE | ID: mdl-33806911

RESUMO

Metastatic features of breast cancer in the brain are considered a common pathology in female patients with late-stage breast cancer. Ca2+ signaling and the overexpression pattern of Ca2+ channels have been regarded as oncogenic markers of breast cancer. In other words, breast tumor development can be mediated by inhibiting Ca2+ channels. Although the therapeutic potential of inhibiting Ca2+ channels against breast cancer has been demonstrated, the relationship between breast cancer metastasis and Ca2+ channels is not yet understood. Thus, we focused on the metastatic features of breast cancer and summarized the basic mechanisms of Ca2+-related proteins and channels during the stages of metastatic breast cancer by evaluating Ca2+ signaling. In particular, we highlighted the metastasis of breast tumors to the brain. Thus, modulating Ca2+ channels with Ca2+ channel inhibitors and combined applications will advance treatment strategies for breast cancer metastasis to the brain.

2.
Foods ; 9(11)2020 Nov 22.
Artigo em Inglês | MEDLINE | ID: mdl-33266446

RESUMO

The objective of this study was to amplify vitamin D2 in white button mushrooms using ultraviolet (UV-B) irradiation and to prepare a vitamin D2-fortified superfine mushroom powder through jet milling. Mushrooms irradiated with UV-B for 30 min had a vitamin D2 concentration of 8.19 µg/g, an amount about 400 times greater than that of the control (0.02 µg/g). The vitamin D2-fortified mushrooms were then freeze-dried and conventionally ground or jet-milled to obtain coarse (Dv50 = 231 µm), fine (Dv50 = 106.3 µm), and superfine (Dv50 = 7.1 µm) powders. The vitamin D2 content was retained during the preparation of the powders. The physical characteristics were evaluated by scanning electron microscopy and hydration properties. The superfine powder of vitamin D2-amplified mushrooms was suitable for use as a functional ingredient because its roughness was significantly reduced, and it had a neutral aroma and taste as determined by descriptive analysis.

3.
Soft Robot ; 2020 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-33216700

RESUMO

Owing to their compliance, lightweight, and high force density characteristics, pneumatic actuation systems have been widely implemented in various soft robots. However, pneumatic actuation systems exhibit low efficiency, poor control performance, and high noise; these make it extremely challenging to widely employ a pneumatic actuation system in mobile robots. To overcome these limitations, many researches were conducted on recycling the compressed air within such systems. However, the proposed approaches do not consider the system efficiency and exhaust performance of pneumatic systems. Therefore, this article proposes a recirculation system using a novel soft re-air valve based on the cardiac structure of fish. In particular, the proposed recirculation system recycles the compressed air to improve the system efficiency and pressurizing performance, and the soft re-air valve simultaneously prevents a decrease in the depressurizing performance. For the validation of the proposed scheme, experiments were conducted to evaluate the system efficiency, control performance, and exhaust noise. In contrast to conventional pneumatic systems, the experimental results revealed that the proposed system increased the overall system efficiency by 47.58%, reduced the position root mean square error by 8.16%, and reduced the exhaust noise by 47.52%.

4.
Foods ; 9(11)2020 Nov 16.
Artigo em Inglês | MEDLINE | ID: mdl-33207640

RESUMO

The effects of a consecutive process of pulsed electric field (PEF) treatment, sous-vide cooking, and reheating on the properties of beef semitendinosus muscle were investigated. Fresh meats were PEF-treated with different electric field strengths of 1.0, 1.5, and 2.0 kV/cm, and then the control and PEF-pretreated beef samples were sous-vide cooked at 60 °C for up to 24 h. The PEF pretreatment resulted in tenderization of the fresh meat proportional to the increase in the electric field strength. A significant decrease in cutting force (by 35%) was observed after PEF treatment at 2.0 kV/cm. The hardness and chewiness of the meat were also significantly reduced by PEF treatment. After sous-vide cooking, the PEF-pretreated samples exhibited a significantly reduced cutting force, redness value (a*), and myoglobin content (mg/g) (p < 0.05). However, there were no significant differences in cooking loss and drip loss (p > 0.05). When the sous-vide-cooked meats were reheated in an oven (230 °C, 5 min), the reduced cutting force induced by the PEF pretreatment was retained.

5.
Pharmaceutics ; 12(3)2020 Mar 02.
Artigo em Inglês | MEDLINE | ID: mdl-32131531

RESUMO

Applications of nanoparticles in various fields have been addressed. Nanomaterials serve as carriers for transporting conventional drugs or proteins through lysosomes to various cellular targets. The basic function of lysosomes is to trigger degradation of proteins and lipids. Understanding of lysosomal functions is essential for enhancing the efficacy of nanoparticles-mediated therapy and reducing the malfunctions of cellular metabolism. The lysosomal function is modulated by the movement of ions through various ion channels. Thus, in this review, we have focused on the recruited ion channels for lysosomal function, to understand the lysosomal modulation through the nanoparticles and its applications. In the future, lysosomal channels-based targets will expand the therapeutic application of nanoparticles-associated drugs.

6.
Int J Mol Sci ; 21(1)2020 Jan 04.
Artigo em Inglês | MEDLINE | ID: mdl-31947992

RESUMO

The bicarbonate ion has a fundamental role in vital systems. Impaired bicarbonate transport leads to various diseases, including immune disorders, cystic fibrosis, tumorigenesis, kidney diseases, brain dysfunction, tooth fracture, ischemic reperfusion injury, hypertension, impaired reproductive system, and systemic acidosis. Carbonic anhydrases are involved in the mechanism of bicarbonate movement and consist of complex of bicarbonate transport systems including bicarbonate transporters. This review focused on the convergent regulation of ion homeostasis through various ion transporters including bicarbonate transporters, their regulatory enzymes, such as carbonic anhydrases, pH regulatory role, and the expression pattern of ion transporters in non-secretory systems throughout the body. Understanding the correlation between these systems will be helpful in order to obtain new insights and design potential therapeutic strategies for the treatment of pH-related disorders. In this review, we have discussed the broad prospects and challenges that remain in elucidation of bicarbonate-transport-related biological and developmental systems.


Assuntos
Bicarbonatos/metabolismo , Anidrases Carbônicas/metabolismo , Bicarbonatos/química , Trato Gastrointestinal/metabolismo , Humanos , Concentração de Íons de Hidrogênio , Sistema Imunitário/metabolismo , Receptores de Inositol 1,4,5-Trifosfato/metabolismo , Transporte de Íons , Músculo Liso Vascular/metabolismo , Neoplasias/metabolismo , Neoplasias/patologia
7.
Biofouling ; 36(10): 1243-1255, 2020 11.
Artigo em Inglês | MEDLINE | ID: mdl-33401969

RESUMO

The purpose of this research was to characterize Listeria monocytogenes from several environmental and clinical sources and assess the efficacy of single and combined physico-chemical treatments in reducing biofilm on lettuce leaves. PCR analysis of L. monocytogenes isolates collected from different clinical (10 strains) and environmental sources (12 strains) was used to look for the presence of one Listeria-specific gene and five virulence genes. Biofilms of L. monocytogenes were developed on lettuce leaves over 24 h. A 5-min ultrasound and a 300-ppm sodium hypochlorite (NaOCl) wash resulted in similar reductions in cell numbers of 0.82 log CFU cm-2. For chlorine dioxide (ClO2) at 60 ppm, the cell numbers were reduced by ∼5.45 log CFU cm-2. A combined treatment of 5 min of ultrasound plus 300 ppm NaOCl or 40 ppm ClO2, provided maximal efficacy, reducing the number of L. monocytogenes on the lettuce surface to non-detectable levels. Therefore, ClO2 has the potential to replace NaOCl for the disinfection of food products in the food industry.


Assuntos
Biofilmes , Listeria monocytogenes , Contagem de Colônia Microbiana , Desinfetantes/farmacologia , Microbiologia de Alimentos , Alface , Folhas de Planta
8.
Foods ; 8(12)2019 Nov 25.
Artigo em Inglês | MEDLINE | ID: mdl-31775330

RESUMO

The use of defatted soybean flour (DSF) in food as a source of dietary fiber has been limited due to its rough texture and bitter taste. Our previous work indicates that superfine DSF prepared by jet milling could overcome these problems, as it positively affected physical and sensory properties. Therefore, differently sized DSFs were incorporated in tofu, and their impacts on physical and sensory properties were investigated in this study. Coarse DSF (Dv50 = 341.0 µm), fine DSF (Dv50 = 105.3 µm), and superfine DSF (Dv50 = 5.1 µm) were prepared by conventional sifting and jet milling. Tofu was made with a 5% addition of differently sized DSFs and without DSF (control tofu). The quality of tofu was evaluated by scanning electron microscopy, color measurement, texture profile analysis, and quantitative descriptive analysis. The tofu made with coarse and fine DSF showed negative changes in its physical and organoleptic qualities, such as reduced yields, a less pure color, a harder texture, and a rougher mouthfeel. However, the tofu made with superfine DSF showed only minimal changes in its qualities compared to the control. Therefore, superfine DSF is a promising fiber supplement that does not change the physical and sensory properties in the making of high-quality tofu.

9.
Nanomedicine (Lond) ; 14(18): 2479-2486, 2019 09.
Artigo em Inglês | MEDLINE | ID: mdl-31456482

RESUMO

Nanoparticles (NPs) have been studied as therapeutic drug-delivery agents for promising clinical trial outcomes. Nanomaterial-based drugs can transfer conventional drugs to target lesions, such as tumors, with increasing efficiency by enhancing drug-cell interaction or drug absorption. Although they are favorable as efficient drug transfer systems, NPs also exhibit cytotoxicity that affects nonpathological regions. Here, we review the basic information behind NP-induced Ca2+ signaling and its participation in channel physiology and pathology. NPs are observed to demonstrate inhibitory or active effects on Ca2+ signaling. Thus, understanding Ca2+ signaling by NPs as a key mechanism in signal transduction will progress the application of nano-drugs in various diseases without deleterious effect.


Assuntos
Sinalização do Cálcio , Cálcio/metabolismo , Portadores de Fármacos/metabolismo , Nanopartículas/metabolismo , Animais , Canais de Cálcio/metabolismo , ATPases Transportadoras de Cálcio/metabolismo , Portadores de Fármacos/toxicidade , Humanos , Nanopartículas/toxicidade , Receptores Acoplados a Proteínas-G/metabolismo , Canais de Receptores Transientes de Potencial/metabolismo
10.
Food Sci Biotechnol ; 27(5): 1531-1539, 2018 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-30319865

RESUMO

The antibacterial efficacy of UV-TiO2 photocatalysis pre-washing in a water-assisted system (UVT, 4.5 mW/cm2, 5-15 min) and high hydrostatic pressure (HHP, 300-500 MPa, 1 min at 25 °C) post-package combined treatment was evaluated against Salmonella Typhimurium inoculated onto whole cherry tomato surfaces and compared with chlorine disinfection (200 ppm). An air pump was fitted at the bottom of UVT reactor to create turbulent flow for rotation of fruits for uniform disinfection. UVT-HHP combined treatment at 500 MPa achieved bacterial reduction of more than 5 log via a synergistic effect, compared with chlorine disinfection. Lycopene and total phenolic contents and antioxidant activities were not significantly changed in tomatoes after any treatment. UVT-HHP combined treatment did not affect the surface color but caused softness in tomatoes. UVT pre-washing followed by HHP post-package treatment can be the effective intervention strategy alternative to conventional chlorine disinfection for production of ready-to-eat (RTE) fresh cherry tomatoes.

11.
Food Microbiol ; 76: 526-532, 2018 Dec.
Artigo em Inglês | MEDLINE | ID: mdl-30166184

RESUMO

Surface disinfection of fresh blueberries is an important food safety challenge due to the delicate texture and short shelf life of these small fruits. A newly designed water-assisted photocatalytic reactor was developed for disinfection of fruits with a delicate texture and complex surface characteristics. Efficacy of UV-TiO2 photocatalysis was evaluated in comparison with UV alone for inactivation of Escherichia coli K12 (as a surrogate for Escherichia coli O157:H7) inoculated onto the surface of the blueberry skin, calyx, and an experimentally prepared agar matrix that was used as a model matrix. Influence of surface characteristics such as surface hydrophobicity and surface free energy on bacterial adhesion were also investigated. The initial bacterial population on all surfaces was approximately 7.0 log CFU/g. UV-TiO2 photocatalysis (4.5 mW/cm2) for 30 s achieved comparatively higher bacterial reductions of 5.3 log and 4.6 log CFU/g on blueberry skin and agar matrix surfaces, respectively, than 4.5 log and 3.4 log CFU/g reductions for UV alone (6.0 mW/cm2). Total phenolic and total anthocyanin contents of fruits were significantly increased after both UV-TiO2 and UV treatments, compared with water washed control fruits. UV-TiO2 photocatalysis technology is a non-chemical and residue-free method with reduced water usage for surface disinfection of fresh blueberries.


Assuntos
Mirtilos Azuis (Planta)/microbiologia , Escherichia coli K12/efeitos dos fármacos , Escherichia coli K12/efeitos da radiação , Conservação de Alimentos/métodos , Titânio/farmacologia , Ágar/química , Aderência Bacteriana/efeitos dos fármacos , Aderência Bacteriana/efeitos da radiação , Mirtilos Azuis (Planta)/química , Contagem de Colônia Microbiana , Escherichia coli K12/crescimento & desenvolvimento , Conservação de Alimentos/instrumentação , Frutas/química , Frutas/microbiologia , Viabilidade Microbiana/efeitos dos fármacos , Viabilidade Microbiana/efeitos da radiação , Raios Ultravioleta
12.
Front Physiol ; 9: 889, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30072910

RESUMO

Secretory glands including salivary glands by many hormonal inputs produce and secrete biological fluids determined by variety of ion transporters. Spinophilin is a multifunctional scaffolding protein, which involved in receptor signaling and regulation of anion exchangers AE2 activity. We found that spinophilin expressed in salivary glands. The role of salivary spinophilin on the modulation of chloride/bicarbonate exchange remains unknown. The spinophilin enhanced AE2 activity and associated with a STE20/SPS1-related kinase and showed an additive effect on the modulation of the activity of AE2. The cholinergic stimulation and subsequent intracellular Ca2+ increase was required for the interaction with AE2 and spinophilin and abrogated the enhanced effect of spinophilin on Cl- transporting activity. Ductal chloride/bicarbonate exchange activity was increased in pretreatment with carbachol. The CaMKII inhibitor KN-93 suppressed the chloride/bicarbonate exchange activity of ducts, suggesting that CaMKII was required for ductal chloride/bicarbonate exchange activity. Additionally, microtubule destabilization by nocodazole attenuated the interaction of AE2 and spinophilin and almost abolished the ductal chloride/bicarbonate exchange activity. The treatment of siRNA-spinophilin on the isolated salivary ducts also reduced the ductal chloride/bicarbonate exchange activity. Therefore, role of salivary spinophilin on AE2 may facilitate the Cl- influx from basolateral in salivary glands in response to cholinergic inputs.

13.
Int J Food Microbiol ; 263: 61-66, 2017 Dec 18.
Artigo em Inglês | MEDLINE | ID: mdl-29031105

RESUMO

The efficacy of microwave-combined cold plasma treatment (MCPT) for inactivating Bacillus cereus spores contaminating red pepper (Capsicum annum L.) flakes was investigated. The effects of red pepper drying method, particle size, and water activity (aw) were also evaluated at two levels of microwave power (1700 and 2500W/cm2). The inactivation effect of MCPT was higher at higher microwave power. Spore reduction was more effective with vacuum-dried red pepper than far-infrared-dried flakes. A significantly higher level of spore reduction was observed with the red pepper sample with a smaller surface to volume ratio when one surface (exterior surface) was inoculated (p<0.05). Spore reduction by MCPT at high microwave power increased from 1.7 to 2.6logspores/cm2 when the aw of flake increased from 0.4 to 0.9 (p<0.05). MCPT did not change the color of red pepper flakes. MCPT demonstrated potential as a microbial decontaminating technology for red pepper flakes.


Assuntos
Bacillus cereus/crescimento & desenvolvimento , Capsicum/microbiologia , Descontaminação/métodos , Gases em Plasma/farmacologia , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/efeitos da radiação , Bacillus cereus/efeitos dos fármacos , Bacillus cereus/efeitos da radiação , Micro-Ondas , Esporos Bacterianos/crescimento & desenvolvimento
14.
Korean J Food Sci Anim Resour ; 37(6): 840-846, 2017.
Artigo em Inglês | MEDLINE | ID: mdl-29725205

RESUMO

We investigated the physicochemical and sensorial properties of hamburger patties made with three different defatted soybean flour (DSF) preparations which differed in particle size. Coarse (Dv50=259.3±0.6 µm), fine (Dv50=91.5±0.5 µm), and superfine (Dv50=3.7±0.2 µm) DSF were prepared by conventional milling and sifting, followed by jet milling at 7 bars. Hamburger patties containing 5% of each DSF were prepared for a property analysis. The hamburger patties made with 5% superfine DSF showed the lowest cooking loss among the treatment groups (p<0.05). The patties with superfine DSF also retained the texture profile values of the control patties in terms of hardness, gumminess, springiness, and chewiness, while the addition of coarse and fine DSF increased the hardness and chewiness significantly (p<0.05). The sensorial results of quantitative descriptive analysis (QDA) indicate that the patties containing superfine DSF were softer and tenderer than the controls (p<0.05). Although the overall acceptability of the patties made with coarse and fine DSF was poor, the overall acceptability of the superfine DSF patty was the same as that of the control patty. These results suggest that superfine DSF is an excellent food material that can supply dietary fiber, while maintaining the physical characteristics and texture of hamburger patty.

15.
Int J Food Microbiol ; 238: 256-264, 2016 Dec 05.
Artigo em Inglês | MEDLINE | ID: mdl-27705845

RESUMO

Human norovirus (HuNoV) is the primary cause of viral gastroenteritis worldwide. Fresh blueberries are among high risk foods associated with norovirus related outbreaks. Therefore, it is important to assess intervention strategies to reduce the risk of foodborne illness. The disinfection efficiency of decontamination methods is difficult to evaluate for fruits and vegetables due to an inconsistent degree of contamination and irregular surface characteristics. The inactivation efficiency and mechanism of murine norovirus 1 (MNV-1, a surrogate for HuNoV) was studied on an experimentally prepared solidified agar matrix (SAM) to simulate blueberries using different wavelengths (A, B, C) of UV light both with and without TiO2 photocatalysis (TP). MNV-1 was inoculated on exterior and interior of SAM and inactivation efficiencies of different treatments were investigated using a number of assays. Initial inoculum levels of MNV-1 on the SAM surface and interior were 5.2logPFU/mL. UVC with TiO2 (UVC-TP) achieved the highest level of viral reduction for both externally inoculated and internalized MNV-1. Externally inoculated MNV-1 was reduced to non-detectable levels after UVC-TP treatment for 5min while there was still a 0.9 log viral titer after UVC alone. For internalized MNV-1, 3.2 log and 2.7 log reductions were obtained with UVC-TP and UVC alone treatments for 10min, respectively. The Weibull model was applied to describe the inactivation behavior of MNV-1, and the model showed a good fit to the data. An excellent correlation between the steady-state concentration of OH radicals ([OH]ss) and viral inactivation was quantified using a para-chlorobenzoic acid (pCBA) probe compound, suggesting that OH radicals produced in the UV-TP reaction were the major species for MNV-1 inactivation. Transmission electron microscopy images showed that the structure of viral particles was completely disrupted with UVC-TP and UVC alone. SDS-PAGE analysis showed that the major capsid protein VP1 was degraded after UVC-TP and UVC alone. Real-time RT-qPCR analysis showed that UVC-TP and UVC alone caused a reduction in the level of viral genomic RNA. Propidium monoazide (PMA) pretreatment RT-qPCR analysis showed that UVC-TP caused damage to the viral capsid protein in addition to viral genomic RNA. UVC both with and without TiO2 was more effective for MNV-1 inactivation than UVB and UVA. Thus, UVC-TP disinfection aimed to reduce levels of food-borne viruses can inactivate viruses present on the surface and internalized in the interior of blueberries.


Assuntos
Mirtilos Azuis (Planta)/virologia , Desinfecção/métodos , Doenças Transmitidas por Alimentos/prevenção & controle , Frutas/virologia , Norovirus/efeitos da radiação , Raios Ultravioleta , Inativação de Vírus/efeitos dos fármacos , Inativação de Vírus/efeitos da radiação , Ágar , Animais , Azidas , Proteínas do Capsídeo/metabolismo , Clorobenzoatos/química , Eletroforese em Gel de Poliacrilamida , Doenças Transmitidas por Alimentos/virologia , Gastroenterite/prevenção & controle , Gastroenterite/virologia , Humanos , Camundongos , Microscopia Eletrônica de Transmissão , Norovirus/fisiologia , Propídio/análogos & derivados , Reação em Cadeia da Polimerase em Tempo Real/métodos , Titânio/química
16.
J Food Prot ; 78(6): 1098-105, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-26038898

RESUMO

Nonpasteurized orange juice is manufactured by squeezing juice from fruit without peel removal. Fruit surfaces may carry pathogenic microorganisms that can contaminate squeezed juice. Titanium dioxide-UVC photocatalysis (TUVP), a nonthermal technique capable of microbial inactivation via generation of hydroxyl radicals, was used to decontaminate orange surfaces. Levels of spot-inoculated Escherichia coli O157:H7 (initial level of 7.0 log CFU/cm(2)) on oranges (12 cm(2)) were reduced by 4.3 log CFU/ml when treated with TUVP (17.2 mW/cm(2)). Reductions of 1.5, 3.9, and 3.6 log CFU/ml were achieved using tap water, chlorine (200 ppm), and UVC alone (23.7 mW/cm(2)), respectively. E. coli O157:H7 in juice from TUVP (17.2 mW/cm(2))-treated oranges was reduced by 1.7 log CFU/ml. After orange juice was treated with high hydrostatic pressure (HHP) at 400 MPa for 1 min without any prior fruit surface disinfection, the level of E. coli O157:H7 was reduced by 2.4 log CFU/ml. However, the E. coli O157:H7 level in juice was reduced by 4.7 log CFU/ml (to lower than the detection limit) when TUVP treatment of oranges was followed by HHP treatment of juice, indicating a synergistic inactivation effect. The inactivation kinetics of E. coli O157:H7 on orange surfaces followed a biphasic model. HHP treatment did not affect the pH, °Brix, or color of juice. However, the ascorbic acid concentration and pectinmethylesterase activity were reduced by 35.1 and 34.7%, respectively.


Assuntos
Bebidas/microbiologia , Citrus sinensis/microbiologia , Escherichia coli O157 , Microbiologia de Alimentos , Frutas/microbiologia , Viabilidade Microbiana , Cloro , Contagem de Colônia Microbiana , Desinfecção/métodos , Manipulação de Alimentos/métodos , Humanos , Pressão Hidrostática , Fotoquímica , Titânio , Raios Ultravioleta
17.
Food Chem ; 187: 106-11, 2015 Nov 15.
Artigo em Inglês | MEDLINE | ID: mdl-25977004

RESUMO

The effects of jet-milling on the physicochemical and sensorial properties of defatted soybean flour (DSF) were investigated. Superfine DSF powder (DSF-JM; D50 = 4.3 ± 0.1 µm) was prepared from DSF powder (DSF-150; D50 = 257.0 ± 1.7 µm) via conventional sifting followed by jet-milling. The jet-milled DSF showed significant increases in hydration properties, with increases in the water-holding capacity, water-solubility index, and swelling capacity of 24%, 39%, and 32%, respectively. Soluble dietary fibre and fat-binding capacity of DSF-JM also increased significantly (p < 0.05). A quantitative descriptive analysis by trained panelists indicated that the sensorial properties of DSF were also modified by jet milling. The DSF-JM showed significant reductions in bitterness and roughness, but sweetness increased, and the colour of DSF-JM changed to a brighter achromatic colour. These results indicate that superfine DSF could be an ingredient used to modify physical and sensorial properties of food.


Assuntos
Farinha , Soja/química , Microscopia Eletrônica de Varredura , Tamanho da Partícula , Pós , Solubilidade , Paladar , Água/química
18.
Korean J Food Sci Anim Resour ; 35(6): 800-6, 2015.
Artigo em Inglês | MEDLINE | ID: mdl-26877640

RESUMO

We investigated the effects of a pulsed electric field (PEF) treatment on microbial inactivation and the physical properties of low-fat milk. Milk inoculated with Escherichia coli, Saccharomyces cerevisiae, or Lactobacillus brevis was supplied to a pilot-scale PEF treatment system at a flow rate of 30 L/h. Pulses with an electric field strength of 10 kV/cm and a pulse width of 30 µs were applied to the milk with total pulse energies of 50-250 kJ/L achieved by varying the pulse frequency. The inactivation curves of the test microorganisms were biphasic with an initial lag phase (or shoulder) followed by a phase of rapid inactivation. PEF treatments with a total pulse energy of 200 kJ/L resulted in a 4.5-log reduction in E. coli, a 4.4-log reduction in L. brevis, and a 6.0-log reduction in S. cerevisiae. Total pulse energies of 200 and 250 kJ/L resulted in greater than 5-log reductions in microbial counts in stored PEF-treated milk, and the growth of surviving microorganisms was slow during storage for 15 d at 4℃. PEF treatment did not change milk physical properties such as pH, color, or particle-size distribution (p<0.05). These results indicate that a relatively low electric-field strength of 10 kV/cm can be used to pasteurize low-fat milk.

19.
Food Microbiol ; 38: 128-36, 2014 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-24290635

RESUMO

Effects of the microwave-powered cold plasma treatments (CPTs) on the inhibition of microorganisms in red pepper powder, including Aspergillus flavus and Bacillus cereus spores, were investigated. Combinations of heat treatment with CPT were investigated for the inhibition of B. cereus spores on the powder. The number of A. flavus was reduced by 2.5 ± 0.3 log spores/g by the CPT with nitrogen at 900 W and 667 Pa for 20 min. CPT at 900 W and 667 Pa for 20 min inhibited naturally occurring total aerobic bacteria in the red pepper powder by approximately 1 log CFU/g. B. cereus spores were inhibited (3.4 ± 0.7 log spores/g reduction) only when heat treatment at 90 °C for 30 min was integrated with the CPT using a helium-oxygen gas mixture at 900 W. Fermi's model and Weibull model adequately described the inhibition of A. flavus on the red pepper powder by the CPT. The changes in treatment temperature and water activity were less than 5.0 °C (initial temperature: 23.8 °C) and 0.22, respectively, and were affected by both treatment power and time (P < 0.05). The CPTs have demonstrated the potential to reduce the microbial counts of red pepper powder and other powder products.


Assuntos
Aspergillus flavus/efeitos dos fármacos , Bacillus cereus/efeitos dos fármacos , Capsicum/microbiologia , Descontaminação/métodos , Conservação de Alimentos/métodos , Gases em Plasma/farmacologia , Aspergillus flavus/crescimento & desenvolvimento , Bacillus cereus/crescimento & desenvolvimento , Capsicum/química , Pós/química , Esporos Bacterianos/efeitos dos fármacos , Esporos Bacterianos/crescimento & desenvolvimento , Esporos Fúngicos/efeitos dos fármacos , Esporos Fúngicos/crescimento & desenvolvimento
20.
Sci Rep ; 3: 2431, 2013.
Artigo em Inglês | MEDLINE | ID: mdl-23942256

RESUMO

Graphene supported Pt nanostructures have great potential to be used as catalysts in electrochemical energy conversion and storage technologies; however the simultaneous control of Pt morphology and dispersion, along with ideally tailoring the physical properties of the catalyst support properties has proven very challenging. Using sulfur doped graphene (SG) as a support material, the heterogeneous dopant atoms could serve as nucleation sites allowing for the preparation of SG supported Pt nanowire arrays with ultra-thin diameters (2-5 nm) and dense surface coverage. Detailed investigation of the preparation technique reveals that the structure of the resulting composite could be readily controlled by fine tuning the Pt nanowire nucleation and growth reaction kinetics and the Pt-support interactions, whereby a mechanistic platinum nanowire array growth model is proposed. Electrochemical characterization demonstrates that the composite materials have 2-3 times higher catalytic activities toward the oxygen reduction and methanol oxidation reaction compared with commercial Pt/C catalyst.

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