Elaine Biondo is graduated in biology from Federal University of Santa Maria (RS, Brazil) and completed his PhD in Botany from Federal University of Rio Grande do Sul. She has published more than 30 papers dealing with on biodiversity and non-conventional edible plants. in reputed journals. Currently, also she has worked at State University of Rio Grande do Sul food microbiology for food and agrochemical applications.
The objective of the present work is to evaluate the antimicrobial activity of aqueous extract from solid waste of Araucaria angustifolia seed (pinhao) and its synergism with heat treatment against Listeria monocytogenes. A broad spectrum of bacteria and fungi were confronted with pinhão coat extract at concentration of 10 g/L and for the synergism test L. monocytogenes was exposed to temperatures of 55ºC, 60ºC or 70ºC for up to 10 min in the presence of the extract water. Results showed that pinhão coat extract inhibited Staphylococcus aureus, Bacillus cereus, L. monocytogenes, L. innocua and Aeromonas hydrophila growth, but did not inhibit the fungi evaluated. Kinetic modeling showed that L. monocytogenes inactivation followed the first order model. Results showed that the inactivation rate constant increased 105% when L. monocytogenes was treated at 55ºC in the presence of pinhão coat extract. Meanwhile, there was an increase of 58% and 42% at 60ºC and 70ºC, respectively, indicating clear a synergism of the heat treatment with the aqueous extract obtained from the food residue. Thus, pinhão coat extract present antibacterial activity against important foodborne bacteria and its combination with heat processing implies in reduction of the thermal stability of L. monocytogenes, indicating that the combination of both techniques can be an interesting tool to be used in food preservation.
The consumption of artisanal beers has increased in Brazil in recent years, which has led to production of a large amount of solid waste and its reutilization has been little explored. In this sense, the objective of the present work is to evaluate the concentration of polyphenols, compounds with antioxidant activity and with antibacterial activity of dried bagasse from a brewery process. In this sense, samples of bagasse obtained from the artisanal production of Pilsen beer were dried at 60ºC, crushed and passed through 1 mm opening sieves. Dried samples of 1 g were subjected to alcoholic extraction (50 mL of ethanol 50:50 v/v) for 30 minutes at 60ºC for spectrophotometric analysis of total polyphenols, flavonols, tartaric esters and the ability to scavenge ABTS and DPPH radicals. For the antibacterial activity evaluation, samples of 1 g of dried residue was kept in 10 mL of boiling water for 15 minutes, and the extract was tested against pathogenic bacteria. The results showed that the aqueous extract obtained had the ability to inhibit the growth of Listeria monocytogenes and Staphylococcus aureus, with inhibition halo of 12±2 mm and 10±1 mm. The extract was not effective to prevent the growth of Bacillus cereus, Salmonella Enteritidis and Escherichia coli. The concentrations of total polyphenols, flavonols and tartaric esters found in the residue were 377.30±24.10 mg of gallic acid equivalent, 38.31±17.10 mg of equivalent routine and 16.57±0.49 mg of acid coffee equivalent per gram of dry bagasse, respectively. The alcoholic extract had the capacity to scavenge 79.53±5.41% of ABTS radicals and 55.12±2.01% of DPPH radicals. Thus, these features indicate that the brewery bagasse has great potential to be used as a functional ingredient, since it presents interesting concentrations of polyphenols and compounds with antioxidant activity besides compounds with the capacity to inhibit the growth of important pathogenic bacteria.
Lisangela Bagatini completed her course in Nutrition from University of Vale do Rio dos Sinos; completed her specialization in Food Quality Management from State Univeristy of Rio Grande do Sul (Brazil) respectively. Currently she is a Master’s Degree student enrolled in the Environmental and Sustaintability Program from the same university and studies the processing and utilization of residues form brewery industries for industrial applications.