Determination of bongkrekic acid in corn flour by direct extraction ultra-high performance liquid chromatography tandem mass spectrometry / 公共卫生与预防医学

Objective To establish a direct extraction ultra-high performance liquid chromatography tandem mass spectrometry method for the determination of bongkrekic acid in corn flour. Methods Bongkrekic acid was directly extracted with 80% methanol from corn flour samples, and the supernatant after vortex and centrifugation was determined after passing through membrane filtration. At the same time, the corn flour samples were extracted by solid phase extraction. The determination results of the two methods were compared. Results The linearity of standard series was good within the range of2-20 μg/L, and the linearity coefficient was＞0.999. The determination result of the positive sample by direct extraction method was 193.40 mg/kg (n=6). Adding the standard to the blank sample at the levels of 2, 6, and 10 μg/L, the calculated recovery rate was 75.82% - 99.33%, and the relative standard deviation was 3.54 % - 8.45%. The detection limit of the method reached 6 μg/kg. After extraction by solid phase extraction, the determination result of the positive sample was 196.84 mg/kg (n=6). The recovery rate was 77.12% -100.83%, with a relative standard deviation of 8.32% - 9.54%. Conclusion Compared with the solid phase extraction, the direct extraction method for the extraction of bongkrekic acid from corn flour has the advantages of rapidity, simplicity, and cost savings.

El enriquecimiento de la harina de maíz precocida y de la harina de trigo en Venezuela. Una gestión con éxito / Enrichment of precooked corn flour and of wheat flour in Venezuela. A successful experience

La crisis iniciada en Venezuela a mediados de 1983 provocó un manifiesto deterioro en la cantidad y calidad del consumo de alimentos por parte de los sectores de mas bajos recursos. Los porcentajes de adecuación más bajos respecto a los Requerimientos de Energía y Nutrientes de la Población Venezolana corresponden a hierro, vitamina A y en menor grado a vitaminas del complejo B. El Instituto Nacional de Nutrición inició en 1990 la factibilidad de enriquecer la harina de maíz precocida, HMP, responsable por un 40 % de las Calorías derivadas de los cereales y de un 15 - 16 % del total de calorías de la dieta, con hierro (fumarato ferroso), vitamina A, tiamina, riboflavina y niacina. En 1992 se propuso un perfil de enriquecimiento requerido para que 50 g de HMP cubriese un 25 % de los requerimientos de estos nutrientes, ya tomados en cuenta las pérdidas durante la preparación de la arepa. El conocimiento de esta medida como política oficial, causó cierta molestia en el sector privado. En Agosto 1992, por Decreto Presidencial No 2.492 se crea la Comisión para el Enriquecimiento Nutricional de los Alimentos, CENA, con el específico propósito del enriquecimiento de la HMP. Con los esfuerzos coordinados del sector oficial y de la industria privada, se pudo llegar a un consenso sobre el perfil de enriquecimiento de la HMP, el cual fue anunciado por la CENA. (por kg): vitamina A: 2.700 ER; tiamina: 3,1 mg; riboflavina: 2,5 mg; niacina: 51 mg; hierro: 50 mg. Comisión Venezolana de Normas Industriales. COVENIN. Harina de maíz precocida. (3 era. Revisión) 2135:1996. Obligatorio cumplimento. Desde febrero 1993 toda la HMP comercializada en Venezuela debe estar enriquecida. Harina de trigo. HT. En noviembre 1992, la Asociación Venezolana de Productores de Trigo, AVPT, presentó un proyecto no obligatorio de fortificación. En Marzo la CENA rechazó el carácter no obligatorio y de acuerdo con la AVPT se acordó un perfil de enriquecimiento para la HT: (por kg): tiamina: 1,5 mg; riboflavina: 2,0 mg; niacina: 20 mg; hierro: 20 mg (como fumarato ferroso). Comisión Venezolana de Normas Industriales. COVENIN. Harina de trigo (4 ta. Revisión) 217: 2001. Obligatorio cumplimiento. Desde agosto 1993 toda la HT comercializada en Venezuela debe estar enriquecida(AU)

TIn Venezuela a severe economic crisis beginning in 1983 provoked a progressive reduction of the quality and quantity of food consumed by the low socioecnomic strata of the population. The lowest adequacy percentages with respect to Venezuelan RDAs were for iron, vitamin A and to a lesser extent, for vitamin B complex. Being precooked corn flour, PCF, responsible for 40 % of the Calories derived from cereals and for 15 -16 % of the total calories intake in the diet, an excellent and unique vehicle for enrichment, the National Institute of Nutrition, NIN, started the investigations toward its fortification with iron (as ferrous fumarate), vitamin A, thiamin, riboflavin and niacin. In 1992 a fortification profile was developed in such a way that 50 g of PCF (amount needed for a 110 g ready-to-eat arepa) covered approximately 25 % of the RDAs for the mentioned nutrients, after taking into consideration the losses due to the cooking process. The announcement of this measure as an official policy, provoked some adverse reactions among the private sector. In August 1992, by Presidential Decree No 2.492, the Commission for the Nutritional Enrichment of Foods, CENA, was created with the specific task of reconciling efforts and carry forward the enrichment of the PCF. With the attendance of key representatives of the corn and wheat industries, the government and the media, the CENA announced the official fortification profile of the PCF (per kg) : vitamin A: 2,700 RE; thiamin: 3.1 mg; riboflavin: 2.5 mg; niacin: 51 mg; iron: 50 mg. Official Venezuelan Bureau of Standars (COVENIN), mandatory Standard No 2135-1996. Since February 1993 all the PCF sold in Venezuela must be enriched. Wheat flour. WF. The Venezuelan Wheat Producers Association, VWPA, presented in november 1992 a tentative and non compulsory fortification profile. In march the CENA voted against the non compulsory character of the fortification of WF and upon agreement with the VWPA, set in force the mandatory fortification profile as follow (per kg): thiamin: 1.5 mg; riboflavin: 2.0 mg; niacin: 20 mg; iron: 20 mg (as ferrous fumarate). COVENIN mandatory Standard No 217:2001. Since august 1993 all the WF sold in Venezuela must be enriched(AU)

Determinación de humedad en harina precocida de maíz blanco utilizando un horno de microondas doméstico / Determination of moisture in flour precooked white corn using a domestic microwave oven

El contenido de humedad es un parámetro de principal interés entre los índices que regulan la calidad de granos, cereales y sus derivados. Los métodos oficiales para determinar la humedad (AOAC 32.1.03, ISO 6540:1980, NTC 2227:86 y COVENIN 2135:96) tienen la desventaja de consumir mucho tiempo en la determinación porque  requieren la desecación de la muestra en estufa. En este trabajo se compara el método propuesto de secado de la muestra de maíz blanco en un horno doméstico de microondas contra el método rápido convencional de termobalanza infrarrojo y los métodos de referencia oficiales AOAC (32.1.03) y COVENIN (2135:96). Se determinaron las condiciones de análisis: tamaño de muestra, tipo de recipiente, distribución de la muestra, condiciones de operación usando un microondas doméstico de 700 W de potencia, así como el secado en uno o varios pasos. Entre el método propuesto y el método de referencia no se encontraron diferencias estadísticamente significativas a p<0,05; el tiempo de secado se redujo de varias horas a pocos minutos: 4 min con 90% de potencia. Como se puede  concluir que es factible la determinación de humedad por volatilización en una matriz de harina precocida de maíz blanco usando un horno de microondas doméstico.

The moisture content is a primary parameter between indices governing the quality of grains, cereals and cereal products. The official methods for determining moisture (AOAC 32.1.03, ISO 6540: 1980, NTC 2227: 86 COVENIN 2135: 96) have the disadvantage of to be time consuming that require drying oven method. The aim in this paper was compare the proposed method of drying sample of white corn with domestic microwave oven against conventional rapid method of infrared thermobalance and official reference methods AOAC 32.1.03 method and COVENIN 2135:96. Sample size, vessel kind, sample container distribution,   operations conditions using domestic 700 W microwave and also analysis employed to one or more drying steps were determined. Between the proposed and the reference method not statistically significant differences were found at P <0.05; drying time was reduced from several hours to a few minutes: 4 min at 90% power. It can be concluded that the determination of moisture by volatilization in a matrix of precooked white corn flour using a domestic microwave oven is feasible.

Efecto de un Secuestrante de Micotoxinas Sobre la Producción de Gas y Degradación Ruminal in Vitro de Harina de Maíz con Aflatoxina B1 / Effect of Mycotoxin Binder on in Vitro Gas Production and Ruminal Degradation of Maize Meal with Aflatoxin B1

Con el propósito de evaluar el efecto de un secuestrante comercial de micotoxinas (SM) con base en glucomananos, sobre la producción de gas y degradación ruminal in vitro, se incubó harina de granos de maíz (Zea mayz L.) en licor ruminal con concentraciones de aflatoxina B1 (AFB1) de 4, 8 y 12 ppb, respectivamente, y proporciones de AFB1: SM de 1:75000 (SM-75), 1:150000 (SM-150) y 1:225000 (SM-225). Adicionalmente, se consideró un tratamiento sin inclusión del secuestrante de micotoxinas (SM-0). La producción de gas se registró a las 3, 6, 9, 12, 16 y 24 h, y la actividad del SM a las 3 h de incubación. La información fue analizada utilizando un diseño completamente aleatorizado con arreglo factorial 3x4. La concentración de AFB1 afectó negativamente (P<0,05) la producción de gas, con el mayor impacto a las 9 h, cuando 12 ppb [5,15 mL/g de materia seca (MS)] generaron una reducción en la producción de gas, en comparación con 4 y 8 ppb (6,57 y 6,01 mL/g MS), respectivamente. Independientemente del nivel utilizado y luego de 24 h de incubación, el uso de SM incrementó (P<0,05) la producción de gas respecto al SM-0 en 25,5% (68,5 vs. 56,6 mL/g MS, respectivamente). En todos los tratamientos, SM-75 mostró la mayor producción de gas, sin mejoras debido a aumentos adicionales en la relación SM:AFB1. La concentración de AFB1 afectó (P<0,05) negativamente la degradación de la MS de la harina de maíz, con una reducción del 39,8%, luego de 12 h de incubación. La capacidad secuestrante fue del 86,0 ± 3,34%, sin diferencias (P>0,05) debida al nivel de AFB1 o a la relación AFB1:SM. Estos resultados demuestran que el aditivo biotecnológico evaluado, reduce el impacto negativo de la AFB1 sobre la producción ruminal in vitro de gas y la degradación aparente de la MS.

To evaluate the effect of a commercial mycotoxin binder (MB) based on glucomannans, on the in vitro gas production and ruminal degradation, maize (Zea mayz L.) grain meal was incubated in ruminal liquor with aflatoxin B1 (AFB1) concentrations of 4, 8 y 12, respectively, and proportions of AFB1: MB of 1:75000 (MB-75), 1:150000 (MB-150), and 1:225000 (MB-225). Additionally, a treatment without MB was considered (MB-0). Gas production was measured at 3, 6, 9, 12, 16, and 24 h, and MB activity after 3 h of incubation. Data was analyzed using a completely randomized design with a 3x4 factorial arrangement. The results show that gas production was negatively affected by AFB1 concentration (P<0.05), with the higher impact at 9 h, when 12 ppb [5.15 mL/g of dry matter (DM)] generated a reduction, when compared to 4 and 8 ppb (6.57 and 6.01 mL/g of DM, respectively). Regardless of the level used and after 24 h of incubation, the use of MB increased (P<0.05) gas production in 25.5%, compared to SM-0 (68.5 vs. 56.6 mL/g of DM, respectively). In all treatments, MB-75 showed the highest gas production without improvements, due to further increases in the ratio MB: AFB1. The AFB1 concentration negatively affected (P <0.05) degradation of DM of maize meal, with a reduction of 39.8%, after 12 h of incubation. The binding capacity was 86.0 ± 3.34%, without differences (P<0.05) due to AFB1 concentration or AFB1: MB relation. These results demonstrate that the assessed biotechnological additive reduces the negative impact of AFB1 on the in vitro ruminal gas production and apparent DM degradation.

Detección de hongos toxigénicos en harinas de maíz precocidas distribuidas en el estado Aragua, Venezuela / Detection of toxigenic fungi in pre-cooked corn flour distributed at Aragua State, Venezuela

Con el fin de detectar la presencia de hongos y aflatoxinas, en harina de maíz precocida distribuida en el estado Aragua, Venezuela, se muestrearon cuatro presentaciones comerciales durante cinco semanas. La cuantificación de hongos se realizó por el método de contaje por incorporación en placa, utilizando agar extracto de malta e incubación durante ocho días a 27± 2 ºC. La determinación de las aflatoxinas se realizó por la prueba de ELISA. El ensayo fue conducido bajo un diseño completamente aleatorio y todos los resultados fueron sometidos a la prueba estadística no paramétrica de Kruskal-Wallis y a pruebas de medias no paramétricas. Los contajes de hongos oscilaron entre 1,79 a 4,7x10UFC de hongos/g de muestra, encontrándose por debajo del nivel establecido por la Norma Covenin 1337-90 de 10(4) UFC/g de harina. Las especies fúngicas identificadas fueron: Aspergillus spp., A. flavus, A. niger, A. terreus y Penicillium spp. Los contenidos de aflatoxinas cumplieron con el nivel de tolerancia permitido para el maíz (20 ng/g).

With the purpose of detecting presence of fungi and aflatoxins in pre-cooked corn flour in Aragua State, Venezuela, we sampled four commercial presentations during five weeks. Quantification of fungi was done by the plate incorporation counting method, using malt extract agar and incubation during 8 days at 27 ± 3ºC. Aflatoxin determination was done by the ELISA test. The assay was conducted under a completely random design and all results were submitted to the Kruskal-Wallis non parametric statistical test, as well as to non parametric means tests. Fungi counts varied between 1.79 and 4.7 x 10 CFU of fungi/g of sample, indicating that they were under the level established by the COVENIN Guideline 1337-90 of 10(4) CFU/g of flour. The fungal species identified were Aspergillus spp., A. flavus, A. niger, A. terreus, and Penicillium spp. The aflatoxin content complied with the tolerance level allowed for corn (20 ng/g).

Gamma-irradiation effect on fumonisin B1 inactivation in corn flour and on aflatoxin M1 in fluid and powdered milk / Influência da irradiação gama na destruição de fumonisina B1 em farinha de milho e de aflatoxina M1 em leite fluido e em pó

Fumonisin B1 is a mycotoxin produced by Fusarium verticillioides and Fusarium proliferatum, and it is found chiefly in corn and corn-based products. Since its discovery fumonisin B1 has been associated with diseases in animals, such as leukoencephalomalacia in horses, and pulmonary edema in swine. On humans, the ingestion of foods with fumonisin B1 is associated with esophageal cancer. Aflatoxin M1 is the principal hydroxylated metabolite occurring in milk from animals which have consumed aflatoxin B1-contaminated feeds. It is also present in milk from nursing mothers who consumed foodstuffs with aflatoxin B1. In this study the effect of gamma-irradiation (60Co) was verified, in doses ranged from 0 to 20 kGy, in order to inactivate fumonisin B1 in corn flour and aflatoxin M1 in fluid and powdered milk. Fumonisin B1 was extracted from the samples with methanol:water (3:1). The extract was purified through immunoaffinity column followed by separation and quantification by means of high-performance liquid chromatography (HPLC) with o-phthaldialdehyde (OPA). For determining aflatoxin M1 the purification was done through immunoaffinity column followed by separation and quantification by means of HPLC with fluorescence detector. Gamma irradiation (60Co) at doses from 3 to 20 kGy reduced the fumonisin B1 content in a range of 11.2 % to 55.5 %. Gamma irradiation (60Co) at 20 kGy dose r

Fumonisina B1 é a micotoxina produzida por Fusarium verticillioides e Fusarium proliferatum e é encontrada principalmente em milho e produtos a base de milho. Desde sua descoberta a fumonisina B1 tem sido associada a doenças em animais, como leucoencefalomalácia em cavalos e edema pulmonar em suínos. Em humanos, o consumo de alimentos com fumonisina B1 tem sido associado com câncer esofágico. A aflatoxina M1 é o principal metabólito hidroxilado encontrado no leite de animais que consumiram rações contaminadas com aflatoxina B1, bem como no leite de lactantes que consumiram alimentos com esta substância. Neste estudo foi verificado o efeito da irradiação gama (60Co), em doses que variaram de 0 a 20 kGy, quanto à capacidade de inativar fumonisina B1 em farinha de milho e aflatoxina M1 em leite fluido e em pó. A fumonisina B1 foi extraída das amostras com metanol:água (8:2). O extrato foi purificado em coluna de imunoafinidade, seguido de separação e quantificação por meio de cromatografia líquida de alta eficiência (CLAE) com detector de fluorescência, após derivatização com ortoftaldialdeído. Para efetuar a determinação da aflatoxina M1, a amostra foi purificada em coluna de imunoafinidade e a separação e a quantificação por meio de CLAE com detector de fluorescência. Foi observada uma redução da concentração da fumonisina B1 na faixa de 11,2 % a 55,5% em doses de 3 a 20 kGy de

Production of High Ethanol Concentration from Raw Corn Flour Using Rhizopus sp. and Saccharomyces cerevisiae / 微生物学通报

A novel raw-starch-digesting glucoamylase producer,Rhizopus sp.W-08,was used in a novel fermentation system of solid-state followed by submerged,and high enzyme activity of 72 IU/mL was obtained.In the following simultaneous saccharification and fermentation process, Saccharomyces cerevisiae Z-06 directly converted raw corn flour to ethanol with the concentration of 21 % (V/V) at 30℃ after 48h.The conversion efficiency of raw corn flour to ethanol was 94.5 % of the theoretical ethanol yield.