Mg Kg-1 In Samples Research Articles

Assessment of aflatoxin and pesticide residue in cowpea (Vigna unguiculata L. Walp.) from North Central Nigeria

Cowpea is a major staple food crop which serves as a source of protein for many Nigerians. Its production and preservation involve the application of pesticides to ensure optimum yield and prevent storage losses. The study evaluated aflatoxin and pesticide residues present in Cowpea grains obtained from retailers in major markets in six States of North Central and the Federal Capital Territory Abuja, Nigeria. The quantitative detection of pesticide residue was conducted through the use of Gas chromatography fitted with Electron Capture Detector (GC-ECD). Aflatoxin (AfB1, AfB2, AfG1 and AfG2) analysis was conducted by the use of thin layer chromatography (TLC). Twenty-three pesticide residues including organochlorine insecticides, dichlorodiphenyltrichloroethane (DDT), dichlorodiphenyldichloroethylene (DDE), dichlorodiphenyldichloroethane (DDD), fungicide (Etridiazole, chloroneb), herbicide (Simazine, atrazine) were detected in cowpea samples. Dichlorodiphenyldichloroethylene (DDE) was present in 95% of the samples while endosulfan sulfate and endosulfan II were detected in 85% of the cowpea samples. Endrin aldehyde, DDT and DDD were the least detected. Pesticides residues in cowpea grains tested ranged from 72.67 mg kg- 1 in samples from Kogi State to 159.67 mg kg-1 in samples from Plateau State which were above the allowable limits of 20 mg kg-1. Aflatoxin was below detectable limits in all the cowpea samples analyzed. The high amount of pesticide residues in the cowpea samples poses health hazards to unsuspecting cowpea consumers.

Impact of food processing and simulated gastrointestinal digestion on gliadin immunoreactivity in rolls.

The enzymatic modification of wheat proteins during dough fermentation and its digestion as supported by peptidases of microbiological origin can result in the degradation of important peptides in the pathogenesis of coeliac disease. However, baking bread and the high temperature associated with this could change the physicochemical and immunological properties of proteins. Thermal changes in the spatial structure of proteins and their hydrolysis can lead to a masking or degrading of immunoreactive peptides. The addition of prolyl endopeptidase (PEP), comprising peptidases isolated from Lactobacillus acidophilus 5e2 (LA) or transglutaminase (TG) in the course of fermentation, decreases its immunoreactivity by 83.9%, 51.9% and 18.5%, respectively. An analysis of the fractional composition of gliadins revealed that γ- and ω-gliadins are the proteins most susceptible to enzymatic modification. Hydrolysis of wheat storage proteins with PEP and LA reduces the content of αβ-, γ- and ω-gliadins by 13.7%, 60.2% and 41.9% for PEP and by 22.1%, 43.5% and 36.9% for LA, respectively. Cross-linking of proteins with TG or their hydrolysis by PEP and LA peptidases during the process of forming wheat dough, followed by digesting bread samples with PEP and LA peptidases, decreases the immunoreactivity of bread hydrolysates from 2.4% to 0.02%. The content of peptide detected in polypeptide sequences is 263.4 ± 3.3, 30.9 ± 1.5 and 7.9 ± 0.4 mg kg-1 in samples of hydrolysates of bread digested with PEP, as produced from dough modified by TG, PEP and LA, respectively. Enzymatic pre-modification of proteins during the process of dough fermentation decreases their immunoreactive potential, such that fewer peptides recognised by R5 antibodies are released during the digestion process from the bread matrix. Immunoreactive peptides are degraded more effectively when digestive enzymes are supported by the addition of PEP. © 2017 Society of Chemical Industry.

Formation of Biogenic Amines in Chicken Meat Stored under Modified Atmosphere

The aim of the study was to investigate the effects of two modified atmospheres with a different combination of gases on selected groups of microorganisms and on concentrations of biogenic amines (BAs) in samples of poultry breast muscle. The samples were packaged under modified atmosphere A (75% O2 a 25% CO2) or B (75% N2 and 25% CO2) and stored at temperatures from +2 to +4 °C for 14 days. During the storage period, O2 concentrations in modified atmosphere A (MA A) decreased from the initial 74.8 ± 0.3% to 55.9 ± 6.6% at the end of the storage period. In all samples, counts of psychrotrophic bacteria counts, Brochothrix thermosphacta, lactic acid bacteria and coliform microorganism were determined. The tests were made on the packaging day, and then after three, nine and fourteen days of storage. At the end of the storage period, higher numbers of psychrotrophic bacteria (6.5 ± 0.7 log10 cfu g-1), Brochothrix thermosphacta (4.8 ± 0.3 log10 cfu g-1) and lactic acid bacteria (1.7 ± 0.4 log10 cfu g-1) were found on samples packaged under MA A. Samples packaged under modified atmosphere B on the other hand contained higher numbers of coliform bacteria (4.1 ± 0.6 log10 cfu g-1) at the end of the storage period. In addition to microbiological indicators, concentrations of biogenic amines (putrescine, cadaverine, histamine, tyramine, spermine, spermidine and β-phenylethylamine) were also determined. In fresh samples and after three days of storage, only spermine and spermidine were found. After 9 and 14 days, also other BAs were detected. The biogenic amine totals at the end of the storage period was 60.0 ± 13.2 mg kg-1 in samples packaged under MA A and 129.0 ± 41.3 mg kg-1 in samples packaged under MA B. The most abundantly represented biogenic amines in samples packaged under MA A were putrescine and spermine (49.7 and 24.8%, respectively, at the end of the storage period), and putrescine and cadaverine in samples packaged under MA B (47.0 and 32.9 %, respectively, at the end of the storage period).

Rendimento da cana-de-açúcar é afetado por flúor

O aquecimento de rochas e solos em indústrias de fundição, siderúrgicas, fertilizantes, vidro e cerâmica liberam compostos contendo flúor (F) na atmosfera. Em área cultivada com duas variedades de cana-de-açúcar no município de Cordeirópolis (SP), adjacente à indústria produtora de cerâmica, foram diagnosticadas queda na produtividade e sintomas de toxidez comparados ao canavial distante da fonte emissora de F. Para a variedade SP80 1816, os teores de F variaram de 56 a 3 mg kg-1 em amostras de folhas coletadas pela técnica da diagnose foliar, ao lado e a 13.000 m da cerâmica, respectivamente. Para a variedade RB83 5089 o teor de F nas folhas foi de 26 mg kg-1 a 80 m da cerâmica. Esses teores estão acima dos considerados normais, de 10 mg kg-1 (ou menor) em áreas sem influência de emissão de F. A produtividade média foi de 54 Mg ha-1 na cana planta (1.º corte) nas duas variedades e na soqueira (2.º corte) de 50 Mg ha-1 para SP80 1816 (mais sensível ao F) e 60 Mg ha-1 para a RB83 5089 (menos sensível ao F). Na área distante 13.000 m da fonte emissora de F não se observou sintomas de toxidez e a produtividade atingiu 82 Mg ha-1 na cana-planta e 100 Mg ha-1 na soqueira para a variedade SP80 1816. O F emitido por indústria de cerâmica sem uso adequado de filtro parece limitar a produtividade da cana-de-açúcar, fato revelado pela diagnose visual, foliar e queda na produção de colmos. Constatou-se, também, na cana-de-açúcar sensibilidade aos efeitos causados pelo excesso de F.