Phytase production through response surface methodology and molecular characterization of Aspergillus fumigatus NF191.

Phytase play an important role in phytic acid catalysis that act as a food inhibitor in cereals. Here, we isolated high phytase producing isolates NF191 closely related to Aspergillus fumigatus sp. from piggery soil. DNA was isolated from the fungal culture and amplified the ITS region using ITS1 and ITS4 primer using PCR. The 400-900 bp amplicon was gel eluted and subjected to sequencing. The sequencing results were assembled and compared with NCBI data base which showed the 99% identity of Aspergilllus fumigatus. Different carbon sources viz., fructose, galactose, lactose, dextrose, sucrose, maltose and different nitrogen sources (organic & inorganic) NH4Cl, NH4NO3, (NH4)2SO4, KNO3, NaNO3, urea, yeast extract, peptone, beef extract were tested for optimal production. The 0.3% dextrose, 0.5% NH4NO3 and 96 h incubation time showed the best production and enzyme activity at 45 ºC incubation temperature. The selected parameters, dextrose, ammonium sulphate and incubation time, when employed with statistical optimization approach involving response surface optimization using Box Behnken Design, gave a 1.3 fold increase in phytase production compared to unoptimized condition.

Fósforo fítico y actividad de fitasa en fórmulas infantiles basadas en cereales

El ácido fítico es un ácido orgánico presente en granos de cereales. El fósforo contenido en su molécula (PFi) no es absorbible por una baja solubilidad, aunque su biodisponibilidad puede incrementarse por la actividad de enzimas fitasas (AFi). Con el objetivo de cuantificar el contenido de PFi y AFi en suplementos elaborados a partir de cereales y destinados a infantes lactantes, se seleccionaron cinco fórmulas de amplia distribución en mercados locales,identificadas de acuerdo a los cereales base de su composición como: A (arroz), T (trigo), ATS (arroz, trigo y aislado de soya), ATM (arroz, trigo y maíz) y ATMS (arroz, trigo, maíz y aislado de soya). Se tomaron cinco muestras por fórmula, cada una correspondiente a un envase (400 a 500 g) elaborado en lotes diferentes y con fecha de vencimiento posterior al muestreo. La proteína cruda varió de 16,8 a 7,2%, con el mayor valor para ATS, y los menores para T y ATM (P< 0,01). El extracto etéreo mostró un rango de 0,31 a 0,75%, mientras la relación calcio:fósforo entre 1,6 en ATM y 1,1 para el resto. El PFi representó el 61,5% del fósforo total en T, con diferencias (P< 0,01) respecto al resto (39,9 ± 6,8%). Sólo se detectó AFi en ATM, T y ATS (570, 300 y 152 U/kg, respectivamente). Se concluye que la composición química se ajustó a lo reportado por los fabricantes, con un elevado contenido de PFi y una AFi fundamentalmente asociados a la presencia de trigo en las fórmulas.

Phytic phosphorus and phytase activity in cerealbased infant formulas. Phytic acid is an organic acid present in cereal grains. The phosphorus inside its molecule (PPhy) is not available because of its low solubility, though the bioavailability could be increased by the activity of phytase enzymes (PhyA). With the purpose of quantifying the PPhy and PhyA in supplements manufactured from cereals and intended for lactating infants, five formulas of wide distribution in local markets were selected and identified depending on the main vegetable ingredients as A (rice), T (wheat), ATS (rice, wheat and soy isolate), ATM (rice, wheat and maize) and ATMS (rice, wheat, maize and soy isolate). Five samples were taken from each formula, each one corresponded to a commercial brand (400 to 500 g), coming from different batches and before their expiration date. The crude protein ranged from 7.2 to 16.8%, with de highest value for ATS and the lowest for T and ATM (P< 0.01). Ether extract varied from 0.31 to 0.75%, while the calcium: phosphorus ratio from 1.6 for ATM, to 1.1 for the rest. The PPhy was 61.5% of the total phosphorus in T, with differences (P<0.01) compared to the other formulas (39.9 ± 6.8%).PhyA was only detected in ATS, T and ATM (152,300 and 570 U/kg, respectively). The chemical composition complied with the manufacturer report, with a high content of PPhy and PhyA associated to the wheat presence in the formula.

Acido fítico: aspectos nutricionales e implicaciones analíticas / Phytic acid: nutritional aspects and analytical implications

This review provides a current summary of the literature concerning various aspects of phytic acid. These include data relative to its chemical structure and physicochemical properties, its occurrence in numerous cereals and legumes, and its role in plants. In addition, the nutritional significance of phytate with regard to its protein and mineral binding abilities, its health benefits and the methods commonly used for the analysis of phytate are discussed.