Purification and characterization of mycoferritin from Aspergillusflavus MTCC 873.

The fungus Aspergillus flavus MTCC 873, a non-toxigenic isolate demonstrated its capability to synthesize mycoferritin (MF) upon induction with iron in yeast extract sucrose (YES) medium. The molecular mass, yield, iron and carbohydrate contents of the MF were 440 kDa, 0.015 mg/g of wet mycelia, 0.8 and 30.4%, respectively. Native gel-electrophoresis revealed a band corresponding to dimeric form of equine spleen ferritin (ESF). Subunit analysis by SDS-PAGE revealed a single protein band with an apparent molecular mass of 24 kDa, suggesting similar sized subunits in the structure of apoferritin shell. Immunological cross-reactivity was observed with the anti-fish liver ferritin. Transmission electron microscopy (TEM) revealed an apparent particle size of 100 Å. N-terminal amino acid sequence of MF revealed a sequence of SLPLQDYA, which showed identities with other eukaryotic ferritin sequences. The spectral characteristics (UV/VIS, fluorescence and circular dichroic spectra) were similar to ESF. The fungus, unlike A. parasiticus 255 (non-toxigenic) was incapable of producing aflatoxins, when grown in YES media.

Nutritional changes in powdered red pepper upon in vitro infection of Aspergillus flavus / Alterações nutricionais em pimenta vermelha em pó após infecção in vitro com Aspergillus flavus

Quantitative losses in various biochemical constituents like capsaicin, carotenes, ascorbic acid, polyphenols,mineral matter, sugars (soluble and insoluble), protein and fat were estimated after the successful growth ofAspergillus flavus for 30 days on powdered red pepper. The fungal biomass was measured by ergosterolcontent and Aflatoxin B1 by HPLC. Amongst the various nutritional constituents evaluated for nutritionallosses and changes the highest nutritional loss was reported in total carotenoids (88.55%) followed by totalsugars (85.5%). The protein content of the infected sample increased from 18.01% to 23%. The nutritional profile of chilli powder (Capsicum annum var. sannam L.) shows highest share of total soluble sugars (32.89%) and fiber content (21.05%), followed by protein (18.01%) and fat (13.32%) making it an ideal solid - substrate for mould growth. At the end of incubation the fungal biomass was 192. 25 mg / 100 gram powder, total plate count 17.5 X 10 4 CFU/g and Aflatoxin B1 content was 30.06 μg / kg.

Foram avaliadas as perdas de vários constituintes bioquímicos como capsaicina, carotenos, acido ascórbico,polifenóis, matéria orgânica, açucares (solúveis e insolúveis), proteína e gordura em pimenta vermelha em pó após a multiplicação de Aspergillus flavus por 30 dias. A biomassa fúngica foi mensurada pelo conteúdo de ergosterol e aflatoxina por HPLC. Entre os vários constituintes avaliados, a maiorperda foi a de carotenóides totais (88,55%), seguido de açucares totais (85,5%). O conteúdo protéico da amostra infectada aumentou de 18,01% para 23%. O perfil nutricional da pimenta em pó (Capsicum annum var. sannam L.) indica alto teor de açucares totais (32,89%) e fibras (21,05%), seguido de proteína (18,01%) e gordura (13,32%), tornando-a umsubstrato ideal para crescimento de fungos. Ao final dos 30 dias, a biomassa fúngica foi 192,25 mg/100g, a contagem total em placas foi 17,5 x 104 CFU/g e o conteúdo de aflatoxina B1foi 30,06 μg/kg.