Dados do Trabalho

Título

EFFECTS OF THE APPLICATION OF COLD PLASMA ON THE MICROBIOTA OF BREAD

Introdução

Bread is a product that has intrinsic characteristics that favor fungal contamination. As it is a widely consumed product, losses due to this type of contamination, which reach 10% in tropical countries, represent great economic losses for nations. One option, which is currently much questioned by the clean label movement, to inhibit the growth of filamentous fungi in this food matrix, is the use of chemical preservatives. This led to the emergence of emerging technologies, such as cold plasma, that could act on this issue. Cold plasma is formed by the ionization of gas after an electrical discharge, generating reactive species, UV radiation, electrons, ions, atoms, and ozone.

Material e Métodos

In the present study, we evaluated the influence of cold plasma of power and frequency 125W and 5.00KHz, respectively, by applying it to sliced bread for 10 min on each side of the slice, and evaluating the microbiota of the product after incubation for 1, 3, 5 and 7 days, comparing with bread with 0.5% calcium propionate and 0.01% sorbic acid (standard) and control bread, without preservatives and plasma application.

Resultados e Discussão

During the first 3 days of storage, there was no visible growth in any of the treatments. On the fourth day, the control showed fungal growth, exceeding the limit of 4 log CFU/g allowed by law. The plasma showed growth only on the seventh day and reduced the microbial population by 2 log CFU/g compared to the control, demonstrating that the technology used had a fungistatic nature, that is, delaying, but not preventing the formation of molds. The two fungal species that grew in both treatments were fungi that naturally contaminate ambient air: Penicillium expansum and Cladosporium cladosporoides. In the plasma mechanism of action, the species formed penetrate the microorganism's cell membrane, and inside the cell, they collapse the organelles and dimerize the DNA.

Conclusão

Standard bread did not show microbial growth during the period evaluated, demonstrating that preservatives are a very consolidated option. Cold plasma is an alternative that needs to be better studied, but which is already showing promising results for the food industry.