scholarly journals Determination of ochratoxin a in coffee by ELISA method and its relationship with the physical, physicochemical and microbiological properties

Revista Vitae ◽  
2021 ◽  
Vol 28 (2) ◽  
Author(s):  
Robinson Monsalve-Atencio ◽  
Karolay Sanchez ◽  
Jairo Camaño ◽  
Seneida Lopera-Cardona ◽  
Blanca Ortiz-Reyes
Keyword(s):  
Physicochemical Properties ◽  
Ochratoxin A ◽  
Pearson Correlation ◽  
Average Particle Size ◽  
Enzyme Linked Immunosorbent Assay ◽  
Expert Committee ◽  
Average Particle ◽  
Microbiological Analysis ◽  
Elisa Method ◽  
Microbiological Properties

BACKGROUND: Coffee is one of the most consumed beverages in the world; however, it may contain toxic compounds such as ochratoxin A (OTA). OBJECTIVES: Determine the OTA’s presence in different types of coffee, intended for beverage preparation and marketed in Colombia through the application of the enzyme-linked immunosorbent assay (ELISA) and analyze its relationship with the physical, physicochemical and microbiological properties. METHODS: 8 samples of coffee commercialized in the Colombian market were selected, in which the OTA content was determined by applying the ELISA method. Likewise, a microbiological analysis was performed, and physicochemical properties were determined, such as moisture content, aw, percentage total dissolved solids (%TDS), and extraction yield (%EY). Physical properties such as free-flow densities, compacted bulk densities (CBD), porosity, average particle size (ASP), and color. The data were treated with multivariate analysis using Principal Component Analysis (PCA) and Cluster Analysis (CA) to quantitatively investigate the relationships between the coffee samples concerning their physical, physicochemical properties, and OTA content. LSD test was applied with a significance level of 95 % and Pearson correlation test. RESULTS: All the samples had OTA content, but only 2 exceeded the limits allowed by the regulations, with a maximum value of 15.449 µg/Kg, which represents 31.449 % of the tolerable daily intake according to the parameters defined by Joint FAO/WHO Expert Committee on Food Additives (JECFA). According to the PCA and CA, the samples were grouped harmonically according to the type of coffee associated with its commercial presentation and industrial process, OTA content, and ASP. OTA content was significantly and positively correlated (p < 0.05) with %EY, %TDS, ASP, porosity, CBD, and moisture. CONCLUSIONS: The coffees marketed in Colombia showed a variable range of OTA, where soluble coffees had higher OTA contents than roasted coffees, and 25 % of the coffees analyzed do not meet the levels defined by Colombian regulations. The OTA content in coffee is related to properties that define the ability to extract solutes from coffee.

Repairing of Subchondral Defect and Articular Cartilage of Knee Joint of Rabbit by Gadolinium Containing Bio-Nanocomposites

2021 ◽  
Vol 17 (8) ◽  
pp. 1584-1597
Author(s):  
Xin Jiang ◽  
Jiang Xiu ◽  
Fuguo Shen ◽  
Song Jin ◽  
Wencai Sun
Keyword(s):  
Articular Cartilage ◽  
Composite Scaffold ◽  
Average Particle Size ◽  
Zealand White Rabbit ◽  
Gelatin Sponge ◽  
Cartilage Defects ◽  
Enzyme Linked Immunosorbent Assay ◽  
Average Particle ◽  
Rabbit Knee ◽  
Tgf Β1

A variety of gadolinium (Gd) based nanoparticles (NPs) were synthesized due to the unique magnetic properties of Gd-containing rare earth compounds and the particularity of micro/nano-materials, which were then incorporated into hydroxyapatite (HA) to obtain inorganic-organic composite materials. Then, HA/Gd NPs containing slow-release transforming growth factor (TGF-β1) were harvested. Adipose-derived stem cells (ADSCs) were extracted from the adipose tissue of a four-month-old New Zealand white rabbit. HA/Gd NPs were attached to absorbable gelatin sponge to obtain HA/Gd NPs/gelatin sponge composite scaffold. In addition, the third generation ADSCs were taken and cultured in the composite scaffold, so that ADSCs-HA/Gd bio-nanocomposites were obtained. The in vitro culture test of osteoblast MC3T3-E1 showed that Gd-containing NPs had good biocompatibility. The prepared HA/Gd NPs loaded with TGF-β1 were spherical, with an average particle size of (9.16 ± 3.16) μm. The NPs were easy to aggregate and adherent. Enzyme-linked immunosorbent assay (ELISA) test results showed that TGF-β1 in NPs was sustained and released continuously for 29 days. HA/Gd NPs/gelatin sponge composite scaffold combined with ADSCs were co-cultured for three days, and the electron microscope showed that the HA/Gd NPs were dispersed, and the cells could adhere and grow well. Then, animal models of rabbit knee articular cartilage defects were established and were rolled into three groups (ADSCs-HA/Gd nano group, HA/Gd nano scaffold group, and blank control). The repair area of the rabbit knee of ADSCs-HA/Gd nano group was smooth and flat, the scaffold was absorbed, the toluidine blue stain was positive, and the type II collagen immunohistochemical stain was positive. In general, ADSCs-HA/Gd nanomaterials were helpful for chondrogenic cell differentiation and had certain adoption prospects in the field of tissue engineering to repair cartilage defects.

scholarly journals Physicochemical properties of particulate matter (PM2.5) from the steel industry in Indonesia

2022 ◽  
Vol 951 (1) ◽  
pp. 012032
Author(s):  
R Ermawati ◽  
I Setiawati ◽  
Irwinanita ◽  
A Ariani
Keyword(s):  
Particle Size ◽  
Particulate Matter ◽  
Physicochemical Properties ◽  
Steel Industry ◽  
Inductively Coupled Plasma ◽  
Fine Particles ◽  
Average Particle Size ◽  
Sampling Period ◽  
Hot Strip Mill ◽  
Average Particle

Abstract Particulate matter (PM) as one of the pollutants in the atmosphere needs to be studied. PM has physical and chemical characteristics and is called physicochemical properties. These properties vary depending on the source of the PM. PM samplers are used for air sampling to characterize some fine particles (PM2.5). The PM2.5 samples have collected from four sampling sites in the steel industry in Cilegon, Indonesia. The sampling sites are the main gate, the hot strip mill, the billet post, and the hot blast plant. The sampling period was four months. The physicochemical properties analysed are morphology, elements content, heavy metals, and particle size. The instruments used to analyse were Scanning Electron Microscopy (SEM) and Energy Dispersive Spectrometry (EDS), Inductively Coupled Plasma Atomic Emission Spectroscopy (ICP-AES), and Particle Size Analyzer (PSA). The morphology of PM2.5 detected varied, but the elements and the most elements found were F and C particles. The metals concentration was below the Indonesia Regulation. While the average particle size analysed was below 2,500 nm. The physicochemical properties of PM2.5 are affected by the type of production process in the industry.

Determination of ochratoxin A in serum and urine of pigs

2012 ◽  
Vol 5 (4) ◽  
pp. 351-356 ◽  
Author(s):  
N. Perši ◽  
J. Pleadin ◽  
A. Vulić ◽  
I. Kmetić ◽  
B. Šimić
Keyword(s):  
Ochratoxin A ◽  
Method Validation ◽  
Screening Method ◽  
Enzyme Linked Immunosorbent Assay ◽  
Elisa Method ◽  
Relative Standard ◽  
Experimental Group ◽  
Simple Screening ◽  
Serum And Urine

The objective of the study was to determine ochratoxin A (OTA) concentrations in serum and urine of pigs during 30-day OTA treatment. OTA was administered orally to the experimental group (n=5) at a dose of 0.78 mg per animal per day, whereas control animals (n=5) were left untreated. OTA concentrations were determined using a validated enzyme-linked immunosorbent assay (ELISA). Method validation resulted in mean recoveries of 93-101% for serum and 98-106% for urine, with acceptable mean inter- and intraday relative standard deviations (<8% for urine and <7% for serum). The ELISA method can be effectively used as a simple screening method to determine OTA exposure in pigs during fattening. The maximum mean OTA concentration in serum was recorded on day 22 (8.75±2.93 ng/ml) and in urine on day 20 (43.56±35.76 ng/ml), indicating significant differences in OTA concentrations between these two matrices.

scholarly journals Mycotoxins in maize: Annual variations and the impact of climate change

2017 ◽  
pp. 63-70 ◽  
Author(s):  
Jovana Kos ◽  
Elizabet Janic-Hajnal ◽  
Anamarija Mandic ◽  
Olivera Djuragic ◽  
Pavle Jovanov ◽  
...  
Keyword(s):  
Climate Change ◽  
Ochratoxin A ◽  
Immunosorbent Assay ◽  
Weather Conditions ◽  
Enzyme Linked Immunosorbent Assay ◽  
Elisa Method ◽  
Annual Variations ◽  
Growing Seasons ◽  
The Republic ◽  
The Impact

The presence of aflatoxins (AFs), ochratoxin A (OTA), zearalenone (ZEA), deoxynivalenol (DON), and fumonisins (FUMs) was examined in maize samples from the Republic of Serbia. The maize samples were collected during the period 2012-2016, and analyzed every year after harvest using validated Enzyme Linked Immunosorbent Assay (ELISA) method. The obtained results were considered regarding the weather conditions parameters recorded during the investigated maize growing seasons. Significant differences in weather-related parameters recorded in the five-year period resulted in different mycotoxin profiles between the investigated years. Obtained results indicate that the presence of ZEA and DON in maize is characteristic of years with abundant precipitation, while AFs and OTA mainly occur in maize during hot and dry years. Furthermore, FUMs were detected with different contamination frequency in maize samples from every year. Based on the findings obtained in this study, as well as on noted changes in weather conditions in the recent years it could be assumed that maize from Serbia may become susceptible to problems concerning mycotoxins. Therefore, there is a necessity for monitoring and research related to the mycotoxins occurrence in maize from Serbia.

Synthesis and Characterization of Bimetallic Fe/Co Nanocatalyst on CNTs for Fischer-Tropsch Reaction

2012 ◽  
Vol 16 ◽  
pp. 9-14 ◽  
Author(s):  
Sardar Ali ◽  
Noor Asmawati Mohd Zabidi ◽  
Duvvuri Subbarao
Keyword(s):  
Particle Size ◽  
Physicochemical Properties ◽  
Average Particle Size ◽  
Xrd Analysis ◽  
Synthesis And Characterization ◽  
Average Particle ◽  
Impregnation Method ◽  
Fischer Tropsch ◽  
Temperature Programmed

Cobalt and iron are common catalysts used in the Fischer-Tropsch (FT) reaction. This paper presents the synthesis and characterization of monometallic and bimetallic cobalt and iron nanoparticles supported on carbon nanotubes (CNTs). The CNTs-supported nanocatalysts were synthesized by a wet impregnation method at various ratios of Fe:Co. The physicochemical properties of the samples were analyzed by H2-temperature programmed reduction (TPR), CO and H2-chemisorption analyses, transmission electron microscopy (TEM) and X-ray diffraction (XRD) analysis. The effects of incorporation of Fe into Co on the physicochemical properties of Co/CNTs in terms of degree of reduction, CO and H2 chemisorptions and morphologies were investigated. TEM showed that metal nanoparticles were well dispersed on the external surface and inside the CNTs. For monometallic Co/CNTs and Fe/CNTs, the average metal particle size was 5±1 nm and 6±1 nm, respectively. For the bimetallic 70Co30Fe/CNTs nanocatalysts, the average particle size was found to be 4±1 nm. Metal particles attached to the outer walls were bigger than the ones inside the CNTs. H2-TPR analysis of Co/CNTs indicated two temperature regions at 330°C (low temperature) and 491°C (high temperature). The incorporation of iron into cobalt nanocatalysts of up to 30 % of the total metal loading enhanced the catalyst’s H2 and CO chemisorptions capacities and reducibility.

Influence of the Freeze-drying Conditions on the Physicochemical Properties and Grinding Characteristics of Kiwi

2020 ◽  
Vol 16 (1-2) ◽  
Author(s):  
Marek Domin ◽  
Dariusz Dziki ◽  
Sybilla Kłapsia ◽  
Agata Blicharz-Kania ◽  
Beata Biernacka ◽  
...  
Keyword(s):  
Physicochemical Properties ◽  
Freeze Drying ◽  
Average Particle Size ◽  
Antioxidant Properties ◽  
Average Particle ◽  
Freeze Dried ◽  
Energy Indices ◽  
Dried Fruit ◽  
Phenolics Content ◽  
Drying Conditions

AbstractThe aim of this work was to study the influence of freeze-drying conditions of kiwi (Actinidia deliciosa) on physicochemical properties and grinding characteristics of dried fruits. Whole kiwi fruits were freeze-dried with the different pressure: 12, 20, 42, 63, 85, and 103 Pa. Dried fruit properties that underwent evaluation included color, texture, rehydration, total phenolics content, antioxidant properties and sensory analysis. Moreover, the grinding energy indices of dried kiwi were determined. The results showed that an increase in the pressure caused decreased lightness, but increased yellowness and greenness of freeze-dried kiwi. The force of kiwi penetration increased and the rehydration ability decreased with the increase in the pressure. The specific grinding energy of dried kiwi ranged from 10.1 to 13.6 kJ⋅kg−1, whereas the average particle size of kiwi powder changed from 0.331 to 0.337 mm. The highest values of these parameters were obtained for kiwi freeze-dried with the highest pressure.

scholarly journals Data analytics approach to predict the hardness of copper matrix composites

10.30544/567 ◽  
2020 ◽  
Vol 26 (4) ◽  
pp. 357-364
Author(s):  
Somesh Kr. Bhattacharya ◽  
Ryoji Sahara ◽  
Dušan Božić ◽  
Jovana Ruzic
Keyword(s):  
Machine Learning ◽  
Composite Materials ◽  
Matrix Composite ◽  
Predictive Accuracy ◽  
Pearson Correlation ◽  
Average Particle Size ◽  
Copper Matrix ◽  
Average Particle ◽  
Matrix Composites ◽  
Copper Matrix Composite

Copper matrix composite materials have exhibited a high potential in applications where excellent conductivity and mechanical properties are required. In this study, the machine learning models have been applied to predict the hardness of the copper matrix composite materials (CuMCs) produced via the powder metallurgy technique. Six different machine learning regression models were employed. The observed CuMCs were reinforced with two different volume fractions (2 vol.% and 7vol.%) of ZrB2 particles. Based on experimental work, we extracted the independent variables (features) like the milling time (MT, Hours), dislocation density (DD, m-2), average particle size (PS, μm), density (ρ, g/cm3), and yield stress (σ, MPa) while the Vickers hardness (MPa) was used as the dependent variable. Feature selection was performed by calculation the Pearson correlation coefficient (PCC) between the independent and dependent variables. The predictive accuracy higher than 80% was achieved for Cu-7vol.% ZrB2 and lower for the Cu-2vol.% ZrB2.

Enhanced catalytic activity of low-Pt content nanocatalysts supported on hollow carbon spheres for the ORR in alkaline media

MRS Advances ◽  
2020 ◽  
Vol 5 (57-58) ◽  
pp. 2961-2972
Author(s):  
P.C. Meléndez-González ◽  
E. Garza-Duran ◽  
J.C. Martínez-Loyola ◽  
P. Quintana-Owen ◽  
I.L. Alonso-Lemus ◽  
...  
Keyword(s):  
Catalytic Activity ◽  
Anion Exchange ◽  
Average Particle Size ◽  
Synthesis Method ◽  
Alkaline Media ◽  
High Catalytic Activity ◽  
Average Particle ◽  
Carbon Spheres ◽  
Hollow Carbon ◽  
Hollow Carbon Spheres

In this work, low-Pt content nanocatalysts (≈ 5 wt. %) supported on Hollow Carbon Spheres (HCS) were synthesized by two routes: i) colloidal conventional polyol, and ii) surfactant-free Bromide Anion Exchange (BAE). The nanocatalysts were labelled as Pt/HCS-P and Pt/HCS-B for polyol and BAE, respectively. The physicochemical characterization of the nanocatalysts showed that by following both methods, a good control of chemical composition was achieved, obtaining in addition well dispersed nanoparticles of less than 3 nm TEM average particle size (d) on the HCS. Pt/HCS-B contained more Pt0 species than Pt/HCS-P, an effect of the synthesis method. In addition, the structure of the HCS remains more ordered after BAE synthesis, compared to polyol. Regarding the catalytic activity for the Oxygen Reduction Reaction (ORR) in 0.5 M KOH, Pt/HCS-P and Pt/HCS-B showed a similar performance in terms of current density (j) at 0.9 V vs. RHE than the benchmark commercial 20 wt. % Pt/C. However, Pt/HCS-P and Pt/HCS-B demonstrated a 6 and 5-fold increase in mass catalytic activity compared to Pt/C, respectively. A positive effect of the high specific surface area of the HCS and its interactions with metal nanoparticles and electrolyte, which promoted the mass transfer, increased the performance of Pt/HCS-P and Pt/HCS-B. The high catalytic activity showed by Pt/HCS-B and Pt/HCS-P for the ORR, even with a low-Pt content, make them promising cathode nanocatalysts for Anion Exchange Membrane Fuel Cells (AEMFC).

A New Method for Direct Determination of the Recoilless Fraction with Application to Magnetic Nanoparticles

2002 ◽  
Vol 721 ◽  
Author(s):  
Monica Sorescu
Keyword(s):  
Room Temperature ◽  
Average Particle Size ◽  
Direct Determination ◽  
Average Particle ◽  
Lattice Method ◽  
Recoilless Fraction ◽  
Single Room ◽  
Magnetite Particles ◽  
Physical Mixtures

AbstractWe propose a two-lattice method for direct determination of the recoilless fraction using a single room-temperature transmission Mössbauer measurement. The method is first demonstrated for the case of iron and metallic glass two-foil system and is next generalized for the case of physical mixtures of two powders. We further apply this method to determine the recoilless fraction of hematite and magnetite particles. Finally, we provide direct measurement of the recoilless fraction in nanohematite and nanomagnetite with an average particle size of 19 nm.

Determination of grinding parameters of fenugreek seed

1970 ◽  
Vol 26 (1) ◽  
pp. 16 ◽  
Author(s):  
S Balasubramanian ◽  
Rajkumar Rajkumar ◽  
K K Singh
Keyword(s):  
Particle Size ◽  
Energy Consumption ◽  
Moisture Content ◽  
Specific Energy ◽  
Feed Rate ◽  
Average Particle Size ◽  
Specific Energy Consumption ◽  
Average Particle ◽  
Fenugreek Seeds ◽  
Fenugreek Seed

Experiment to identify ambient grinding conditions and energy consumed was conducted for fenugreek. Fenugreek seeds at three moisture content (5.1%, 11.5% and 17.3%, d.b.) were ground using a micro pulverizer hammer mill with different grinding screen openings (0.5, 1.0 and 1.5 mm) and feed rate (8, 16 and 24 kg h-1) at 3000 rpm. Physical properties of fenugreek seeds were also determined. Specific energy consumptions were found to decrease from 204.67 to 23.09 kJ kg-1 for increasing levels of feed rate and grinder screen openings. On the other hand specific energy consumption increased with increasing moisture content. The highest specific energy consumption was recorded for 17.3% moisture content and 8 kg h-1 feed rate with 0.5 mm screen opening. Average particle size decreased from 1.06 to 0.39 mm with increase of moisture content and grinder screen opening. It has been observed that the average particle size was minimum at 0.5 mm screen opening and 8 kg h-1 feed rate at lower moisture content. Bond’s work index and Kick’s constant were found to increase from 8.97 to 950.92 kWh kg-1 and 0.932 to 78.851 kWh kg-1 with the increase of moisture content, feed rate and grinder screen opening, respectively. Size reduction ratio and grinding effectiveness of fenugreek seed were found to decrease from 4.11 to 1.61 and 0.0118 to 0.0018 with the increase of moisture content, feed rate and grinder screen opening, respectively. The loose and compact bulk densities varied from 219.2 to 719.4 kg m-3 and 137.3 to 736.2 kg m-3, respectively.  

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