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1.
Sci Rep ; 7(1): 12453, 2017 09 29.
Artigo em Inglês | MEDLINE | ID: mdl-28963539

RESUMO

Adsorption plays an important role in the removal of mycotoxins from feedstuffs. The main objective of this study was to investigate the efficacy of using magnetic graphene oxide nanocomposites (MGO) as an adsorbent for the reduction of Fusarium mycotoxins in naturally contaminated palm kernel cake (PKC). Liquid chromatography-tandem mass spectrometry (LC-MS/MS) was used to assess the mycotoxins in animal feed. Target mycotoxins included the zearalenone (ZEA), the fumonisins (FB1 and FB2) and trichothecenes (deoxynivalenol (DON), HT-2 and T-2 toxin). Response surface methodology (RSM) was applied to investigate the effects of time (3-7 h), temperature (30-50 °C) and pH (3-7) on the reduction. The response surface models with (R2 = 0.94-0.99) were significantly fitted to predict mycotoxins in contaminated PKC. Furthermore, the method ensured a satisfactory adjustment of the polynomial regression models with the experimental data except for fumonisin B1 and B2, which decrease the adsorption of magnetic graphene oxide (MGO). The optimum reduction was performed at pH 6.2 for 5.2 h at of 40.6 °C. Under these optimum conditions, reduced levels of 69.57, 67.28, 57.40 and 37.17%, were achieved for DON, ZEA, HT-2, and T-2, respectively.


Assuntos
Fumonisinas/isolamento & purificação , Grafite/química , Nanopartículas de Magnetita/química , Nanocompostos/química , Tricotecenos/isolamento & purificação , Zearalenona/isolamento & purificação , Adsorção , Ração Animal/análise , Animais , Análise Fatorial , Contaminação de Alimentos/análise , Fusarium/química , Fusarium/patogenicidade , Concentração de Íons de Hidrogênio , Nanopartículas de Magnetita/ultraestrutura , Nanocompostos/ultraestrutura , Óleo de Palmeira , Óleos de Plantas/química , Temperatura
2.
Artigo em Inglês | MEDLINE | ID: mdl-24786623

RESUMO

As, Cd, Pb and Hg were analysed in commonly consumed spices and herbs in Malaysia. The range of As, Cd, Pb and Hg content was 0.24-2.54, 0.23-8.07, 1.54-8.94 and 0.06-0.52 µg g(-1), respectively. The highest concentration of Cd, Pb and Hg in spices and herbs exceeded the maximum permitted proportion, which are 1, 2 and 0.05 µg g(-1), respectively. This study suggests further monitoring of Cd, Pb and Hg on daily consumption of spices and herbs and its toxicological implication for consumers since only the amount of As was lower than the permitted concentration.


Assuntos
Metais Pesados/análise , Especiarias/análise , Arsênio/análise , Cádmio/análise , Contaminação de Alimentos/análise , Chumbo/análise , Malásia , Concentração Máxima Permitida , Mercúrio/análise , Controle de Qualidade
3.
Int J Food Sci Nutr ; 52(3): 251-61, 2001 May.
Artigo em Inglês | MEDLINE | ID: mdl-11400474

RESUMO

The characterization and fat migration of palm kernel stearin (PKS) and desiccated coconut, used as base filling centre in dark chocolate were studied. C36 and C38 triglycerides of PKS decreased by 11% and 9.6% respectively, whereas C32 and C34 increased by 97% and 48% respectively. The change in the triglycerides composition of PKS shift the melting point of PKS from 33.2 to 31.4 degrees C. Solid fat content (SFC) of PK reduced by 40% at 30 degrees C. The rate of fat migration was very slow at 18 degrees C storage compared to 30 degrees C. The rate of change of C36 in the chocolate layer was 0.1% week-1 and 1.2% week-1 at 18 and 30 degrees C respectively. Chocolate stored at 18 degrees C showed post hardening during storage period and withstood bloom during the storage period, whereas that stored at 30 degrees C became soft and bloomed faster after 3 weeks of storage.


Assuntos
Doces , Tecnologia de Alimentos , Óleos de Plantas , Cacau , Óleo de Coco , Conservação de Alimentos , Dureza , Humanos , Óleo de Palmeira , Temperatura , Triglicerídeos/química
4.
J Agric Food Chem ; 48(10): 5041-5, 2000 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-11052775

RESUMO

Latent polyphenol oxidase (LPPO), an enzyme responsible for the browning reaction of sago starches during processing and storage, was investigated. The enzyme was effectively extracted and partially purified from the pith using combinations of nonionic detergents. With Triton X-114 and a temperature-induced phase partitioning method, the enzyme showed a recovery of 70% and purification of 4. 1-fold. Native PAGE analysis of the partially purified LPPO revealed three activity bands when stained with catechol and two bands with pyrogallol. The molecular masses of the enzymes were estimated by SDS-PAGE to be 37, 45, and 53 kDa. The enzyme showed optimum pH values of 4.5 with 4-methylcatechol as a substrate and 7.5 with pyrogallol. The LPPO was highly reactive toward diphenols and triphenols. The activity of the enzyme was greatly enhanced in the presence of trypsin, SDS, ethanol, and linoleic acid.


Assuntos
Catecol Oxidase/metabolismo , Plantas/química , Catecol Oxidase/química , Eletroforese em Gel de Poliacrilamida , Ativação Enzimática , Especificidade por Substrato
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