Fernanda Arnhold Pagnussatt

Inhibition of Fusarium graminearum growth and mycotoxin production by phenolic extract from Spirulina sp.

Fusarium graminearum is a fungal species complex pathogenic occurring worldwide, mainly associated with cereal crops. The most important Fusarium mycotoxins are fumonisins, zearalenone and trichothecenes. The availability of efficient control measures that are less harmful to both the environment and the consumers is urgent. For such, phenolic acids (PAs) from natural sources are known to reduce fungal contaminations. This work aimed to identify the PAs present in a culture extract of Spirulina algae (strain LEB-18) and evaluate its effect on mycelial growth rate, glucosamine level, amylase activity and mycotoxin production by four strains of two lineages of F. graminearum. Results showed that amendment of potato dextrose media with LEB-18 extract (3% w/v), which was mainly composed by gallic acid, greatly reduced radial growth of fungal colonies compared to media containing a single PA and the control. Also, average reductions of 40% and 62% in the glucosamine levels and the amylase activity were observed. In general, the LEB-18 extract and the PAs reduced mycotoxin concentration, with an average reduction of 68% for the trichothecene mycotoxins deoxynivalenol and nivalenol.

Assessment of the encapsulation effect of phenolic compounds from Spirulina sp. LEB-18 on their antifusarium activities

This study aimed to investigate the antifungal activity of liposomal systems containing Spirulina sp. LEB-18 phenolic extract (PE) against Fusarium graminearum (Fg) isolates. The interaction between PE and phosphatidylcholine-based liposomes was monitored by HATR-FTIR, NMR, DSC, and cryo-TEM. After encapsulation, the active principle was released slower than the free PE, a fact that makes the former very promising as a natural antifungal. The PE encapsulation in the liposomes was responsible for changes in the dynamics of specific regions. These compounds affected the membrane hydration degree, ordered the lipid phosphate region and increased the disorder of the acyl chain methylenes. These physico-chemical effects may be related to the strong inhibition of four Fg isolates. Results were discussed by correlating structural similarities, as well as the membrane effects of the PE under study on antifusarium activities, and those found in the literature, thus enabling the PE mechanisms of action to be analyzed.

Technological and nutritional assessment of dry pasta with oatmeal and the microalga Spirulina platensis

Summary Wheat fl our is the most important raw material in the production of pasta. The production process consists of mixing water and fl our, kneading, extrusion and drying. Oats and the microalga Spirulina platensis play a physiological role in the growth, development and maintenance of the human organism due to their high nutritional value. The aim of this study was to assess the technological and nutritional properties of dry pasta prepared with the addition of oatmeal and Spirulina platensis. The wheat fl our was characterized and the effect of partial replacement by oatmeal and Spirulina platensis (Arthrospira platensis) was evaluated using response surface methodology (RSM). The mixtures were analysed for moisture, protein, ash, colour, particle size, falling number and alveography. The formulated pastas were dried and evaluated for moisture, colour, cooking test, acidity, proximate composition and amino acids. Generally, the addition of Spirulina platensis infl uenced the soluble solids content and colour of the pasta, while the oatmeal mainly affected the acid content. The oatmeal increased the values of crude protein and total dietary fi bre (13.06%) when compared with the commercial pasta (2.40%) and may be considered as a source of fi

α-Amylase Inhibitors from Wheat Against Development and Toxigenic Potential of Fusarium verticillioides

Fusarium verticillioides is one of the most important pathogens in maize and is a producer of fumonisin B1 (FB1). Although reports of its presence in wheat are scarce, the susceptibility of this cereal to fungus of the same genus motivates interest in investigating compounds present in the grain with inhibitory activity against this species. The aim of this study was to extract α-amylase inhibitors from wheat and apply them in vitro to evaluate its effect on the development and expression of toxigenic potential of F. verticillioides. The α-amylase inhibitors, both crude (P0) and purified (P1), were applied to in vitro culture containing a pathogen mycelium disc. Mycelial growth of the pathogen, glucosamine content, α-amylase activity, and production of FB1 were investigated. All protein extracts of wheat showed the ability to inhibit pathogen growth, especially the extract P0 from cultivar Quartzo, which resulted in a reduction of glucosamine content (66%) and α-amylase activity (84%). Furthermore, the pr...