87 research outputs found

    Detection and Reduction of Aflatoxin and Orchratoxin A in Black and White Pepper

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    Despite the serious side effects of aflatoxins (AFs) and ochratoxin A (OTA) on human health, there is no published method for the reduction of AFs and OTA in black and white peppers. In light of this, this thesis describes methods that can be used to reduce AFs and OTA in black and white peppers. The separation and quantification of OTA by high performance liquid chromatography (HPLC) in black and white peppers was optimized. The influence of three variables: type of solvent, solvent-volume-to-sample-size (v/w), and amount of sodium chloride (NaCl) (g) on recovery of OTA was evaluated. The response surface methodology (RSM) was applied to determine the optimum amount of NaCl and solventvolume-to-sample-size on the extraction of OTA from black and white peppers. This optimized method proved to be reliable with recovery values ranging from 94.3 to 102.0%. In order to assess occurrence of AFs and OTA in pepper commercialized in Malaysia, samples of black and white pepper were randomly collected from supermarkets and wholesales located in Peninsular Malaysia. Results showed that 58.3 and 67.5% of samples were contaminated with AFs and OTA, with concentrations ranging from 0.1- 25.8 and 0.30-33.0 ng/g, respectively. In order to reduce AFs and OTA in black and white pepper, a method was established by using gamma ray at doses within the range 5 to 30 kGy at 12 and 18% p pper moisture contents. Results showed that the method could not completely reduce OTA and AFs even at dose of 30 kGy and 18% moisture content. The second method proposed applied chemical compounds including acids, alkalis, salts and oxidizing agents for reduction of AFs and OTA. The highest reduction (41.9 – 57.3%) was obtained by using alkaline compounds. This study also optimized a method for reducing AFs and OTA in white pepper. The RSM was used to evaluate the effect of four variables, i.e., time (20-60 min), temperature (30-70 ºC), calcium hydroxide (0-1%) and hydrogen peroxide (1-3%), on reducing AFs and OTA during soaking. A treatment time of 57.8 min, temperature of 62 ºC, calcium hydroxide concentration of 0.6% (w/v), and hydrogen peroxide concentration of 2.8% (v/v) were found to be the optimum conditions for achieving the highest value of mycotoxin reduction and the best value for color. Maximum reduction at the optimum conditions ranged from 70.7 for AFB2 to 100% for AFG1, respectively. Since hydrogen peroxide caused damage to the surfaces of black pepper, this method was not applicable for black pepper. Therefore, the effect of sodium hydrosulfite at different concentrations (0.25, 0.5, 1, 1.5 and 2%) during boiling and sterilization was investigated. The boiling was done at 100 °C and atmospheric pressure for 30 min while sterilization was done under high pressure (1.5 bar) and 121 ºC for 15 min. The maximum reductions were obtained by applying sterilization at 2% of Na2S2O4 and corresponded to 96.0, 96.1, 77.7, 100% and 100% for OTA, AFB1, AFB2, AFG1 and AFG2, respectively. By applying these methods to black and white peppers,more than 95% reduction of OTA and the aflatoxins B1, and G1, which are the most dangerous mycotoxins, was obtained

    Natural Occurrence of Aflatoxins Contamination in Commercial Spices in Iran

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    A total of 80 sample of spices (red pepper, black pepper, turmeric and cinnamon), commercialized in Iran, was analyzed for aflatoxins B1, B2, G1 and G2 content using high-performance liquid chromatography (HPLC) with a fluorescence detector (FD). A mixture of acetonitrile–methanol–water (17:29:54; v/v) was used as the mobile phase and an immunoaffinity column (IAC) applied as a cleanup method. All kinds of spice samples were spiked with aflatoxins B1, B2, G1 and G2 at levels of 1, 10, and 30 ng/g and recovery values were determined. Results showed recoveries ranged from 76.4±5.6 to 98.3±3.2 for AFG1 in cinnamon (spiked at 1ng/g) and AFB2 in turmeric (spiked at 10ng/g) respectively. Thirty-two out of 80 (40%) samples were contaminated with aflatoxins ranged from 0.85±0.10 to 24.60±0.12. Aflatoxin B1 was detected in all of the contaminated samples at the highest concentration as compared with other aflatoxins. Red pepper was significantly (p≤0.05) more contaminated than other spices

    Optimization and validation of a method for extraction and quantification of ochratoxin A in black pepper

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    The extraction method for the determination of ochratoxin A (OTA) in black pepper was optimized. The influence of three variables, i.e., type of solvent, solvent-volume-to-sample-size ratio (v/w) and amount of sodium chloride (NaCl) (g), on OTA recovery was evaluated. Analysis of variance was used to compare recovery values obtained from different solvents, and response surface methodology (RSM) was used to determine the optimum amount of NaCl and the solvent-volume-to-sample-size ratio. The concentration of OTA was determined by high-performance liquid chromatography with fluorescence detection. The highest recovery (95.2 %) was obtained when methanol/water (80:20, v/v) was used as the solvent. The RSM results showed that the experimental data could be adequately fitted to a second-order polynomial model with multiple regression coefficients (R2) of 0.962. The optimum amount of NaCl was determined to be 3 g, whereas the optimum solvent-volume-to-sample-size ratio (v/w) was found to be 4. The proposed method was applied to 20 samples, and the presence of OTA was found in 8 (40%) samples ranging from 0.11 to 3.16 ng g-1

    A review of aflatoxin M1 in liquid milk

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    Mycotoxins continue to pose a health concern via human exposure to contaminated food. Aflatoxin M1 (AFM1), the hydroxylated metabolite of aflatoxin B1 (AFB1), may be found in the milk of dairy cattle and other mammals. In humans, AFM1 is excreted through the feces, urine, and in the case of lactating mothers, also in breast milk after consumption of aflatoxin contaminated food. Concentration of AFM1 in milk is a function of several factors, namely: animal type, milking day, milk yield, season, feeding regime, geographic, and climatic conditions. A linear relationship has been established between the amount of AFM1 in milk and the amount of AFB1 in feed consumed by animals, emphasized at first on the reduction or removal of AFB1 from feedstuffs and then elimination of AFM1 from milk. This review aims to bring up to date the current global status of AFM1 contamination of liquid milk destined for human consumption and the effects of processing and reduction methods on the elimination of aflatoxins from liquid milk

    Comparison of Bacterial Cellulose Production among Different Strains and Fermented Media

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    The effect of different carbon sources on bacterial cellulose production by Gluconacetobacter xylinus (PTCC 1734) and two newly isolated strains (from vinegar) under static culture conditions was studied. The production of bacterial cellulose was examined in modified Hestrin-Shramm medium by replacing D-glucose with other carbon sources. The results showed that the yield and characteristics of bacterial cellulose were influenced by the type of carbon source. Glycerol gave the highest yield in all of the studied strains (6%, 9.7% and 3.8% for S, A2 strain and Gluconacetobacter xylinus (PTCC 1734), respectively). The maximum dry bacterial cellulose weight in the glycerol containing medium is due to A2 strain (1.9 g l-1) in comparison to Gluconacetobacter xylinus as reference strain (0.76 g l-1). Although all of the studied strains were in Gluconacetobacter family, each used different sugars for maximum production after glycerol (mannitol and fructose for two newly isolated strains and glucose for Gluconacetobacter xylinus). The maximum moisture content was observed when sucrose and food-grade sucrose were used as carbon source. Contrary to expectations, while the maximum thickness of bacterial cellulose membrane was attained when glycerol was used, bacterial cellulose from glycerol had less moisture content than the others. The oxidized cellulose showed antibacterial activities, which makes it as a good candidate for food-preservatives

    A Review on Aflatoxins Reduction in Food

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    Aflatoxins (AFs) are cancerous secondary metabolites produced primarily by Aspergillus flavus and Aspergillus parasiticus in agricultural foodstuff such as peanuts, maize grains, cereals, and animal feeds. Food and Agricultural organization (FAO) estimated that as much as 25% of the world’s agricultural commodities are contaminated with mycotoxins, leading to significant economic losses. Moreover, AFs are highly toxic, mutagenic, teratogenic and carcinogenic. Therefore AFs reduction in food and feedstuffs is a major global concern. This review aims to bring up to date the detoxification methods applied for reduction of aflatoxins by physical (cleaning, heating, irradiation, adsorption), chemical (chemical compound, ozonization) and biological (applying bacteria, yeast and nontoxigenic Aspergillus strains) methods in different foods from 2000 to 2015. Papers related to aflatoxin reduction by managing aflatoxins risks, using resistant crops varieties, and good agricultural practices and papers related to other aflatoxins (M1, M2) were excluded

    Optimization and validation of a method for extraction and quantification of ochratoxin A in black pepper

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    Abstract The extraction method for the determination of ochratoxin A (OTA) in black pepper was optimized. The influence of three variables, i.e., type of solvent, solvent-volume-to-samplesize ratio (v/w) and amount of sodium chloride (NaCl) (g), on OTA recovery was evaluated. Analysis of variance was used to compare recovery values obtained from different solvents, and response surface methodology (RSM) was used to determine the optimum amount of NaCl and the solvent-volume-to-sample-size ratio. The concentration of OTA was determined by high-performance liquid chromatography with fluorescence detection. The highest recovery (95.2 %) was obtained when methanol/water (80:20, v/v) was used as the solvent. The RSM results showed that the experimental data could be adequately fitted to a second-order polynomial model with multiple regression coefficients (R 2 ) of 0.962. The optimum amount of NaCl was determined to be 3 g, whereas the optimum solvent-volume-to-sample-size ratio (v/w) was found to be 4. The proposed method was applied to 20 samples, and the presence of OTA was found in 8 (40%) samples ranging from 0.11 to 3.16 ng g -1

    Plasma Therapy for Medication-Related Osteonecrosis of the Jaws- A Case Report

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    Medication-related osteonecrosis of the jaw (MRONJ) is a side effect of anti-bone resorption medications. Nowadays antiresorptive medications like bisphosphonate and monoclonal antibodies like denosumab that have been prescribed for bone disorders and metastatic cancer are becoming increasingly common. Although these medications are quite efficient at reducing bone resorption, they can develop osteomyelitis and jaw necrosis as a side effect. A 65-year-old woman was referred to the Oral Medicine Department of Semnan University of Medical Sciences with diffuse bilateral mandibular osteonecrosis, with a history of osteopetrosis and under-treatment of bisphosphonate. This complication started after tooth extraction and without any healing 5 years ago. After 3 sessions of plasma therapy, obvious improvement was seen. A proper medical history and a routine oral examination before treating with any invasive dental treatment are necessary to avoid any medication-related osteonecrosis of the jaw or mucosal abnormalities

    Comparison of Propolis and Calcium Hydroxide in terms of Mineralization and Cytotoxicity Using Dental Pulp Stem Cells

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    Objectives: This study aimed to compare the in vitro cytotoxic activity of propolis, a bioactive material made by the honeybee, and calcium hydroxide (CH) and their effect on formation of mineralized nodules by human dental pulp stem cells (HDPSCs).Methods: In this in vitro study, HDPSCs were obtained from the Cellular and Molecular Oral Biology Laboratory of School of Dentistry, Shahid Beheshti University of Medical Sciences. In order to evaluate the proliferative effect of propolis and CH, HDPSCs were incubated with different concentrations of propolis (0-32mg/mL) and CH (0-4.8 mg/mL). Twenty-four and 48 hours later, the methylthiazolyl diphenyl-tetrazolium bromide (MTT) assay was carried out to evaluate the proliferation potential and viability of HDPSCs treated with propolis and CH. The effect of propolis and CH on mineralization of HDPSCs was assessed by alizarin red staining.Results: The MTT assay revealed that propolis at its highest concentration caused the greatest proliferation after 24 and 48 hours. Alizarin test showed that the lowest concentrations of CH and propolis at 14 days induced the formation of calcium nodules but at 21 days, propolis was deposited on the cells and calcification was not well recognizable.Conclusion: Propolis led to higher cell vitality at all concentrations in comparison to CH. However, due to its deposition on the cells, its effects on mineralization at 48 hours could not be determined

    Production and Characterization of Biosurfactants Using Bacteria Isolated from Acidic Hot Springs

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      Background and objective: Biosurfactants are increasingly used by food industries due to their low toxicities and unique structures. In this study, biosurfactants were produced and characterized for the first time using acidic bacteria isolated from acidic hot springs in Bushehr Province, Iran. Material and methods: Screening and identification of the most efficient species for biosurfactant production were carried out on 12 bacterial species using several experiments such as hemolysis, surface tension, emulsification index and diameter of clear zone. In addition to biosurfactant production, kinetics, stability and structural and thermal analysis were carried out for the bacterial strains using thin layer chromatography, Fourier Transform Infrared, nuclear magnetic resonance and differential scanning calorimetry. Results and conclusion: The biosurfactant from the selected bacteria (0.1 g l-1) was thermally stable at 120°C for 30 min. Stability at temperatures up to 140°C was confirmed using differential scanning calorimetry. The most significant novelty included the fact that the surface property was preserved until an osmolarity of 4% w v-1. Decreased surface tension and the emulsification potential were only reported at concentrations higher the highlighted concentration. Biological assay showed that Staphylococcus aureus was susceptible to produced biosurfactants, while no susceptibility was seen in Escherichia coli. Degeneration of SW480 cell line exposed to 0.601 µg µl-1 of the biosurfactant was detected after 24 h. The structural analysis showed that the biosurfactant was similar to surfactin as a food bioemulsifier. Conflict of interest: The authors declare that they have no conflict of interest
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