Browsing by Author "Mateus, Tânia"
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- Production of split table olives of the Cobrancosa cultivar: a kinetic study of the fermentation profilePublication . PRATA, JESSICA; Barros, Tânia; Mateus, Tânia; Quintas, Célia; Pires-Cabral, PaulaThe aim of this study was to evaluate the effect of the Cobrancosa cultivar olive ripeness on the physicochemical parameters and model their progression profile throughout the fermentation period. Green and turning color olives undertook fermentation due to fruit and environmental microbiota resulting in final brines with the required acidity values and absence of coliforms, Escherichia coli, Salmonella and Listeria monocytogenes. The Monod model was used to explain the changes of a(W), total acidity and total phenolic content in the brines, and the same kinetic with inhibition was fitted to the changes of reducing sugar concentration in the brines. The inverse power model was adjusted to salt content in brines, a(W), total acidity, reducing sugars and total phenolic content in the olives. The Naperian logarithmic function was fitted to the changes of the surface color parameter (-a/b) of the fruits. For both olives, the models adjusted to the experimental data were the same, showing a similar trend in the physicochemical profiles, probably due to the previously fruit splitting, which promotes nutrients diffusing into the brines and the influx of salt into the olives during fermentation. However, different model parameters were estimated, depending on the ripeness degree, namely for total acidity, reducing sugars and total phenolic content of the brines, showing lower nutrients diffusion rates from the unripe olive pulp, through the skin into the brine, due to the hardness of the cell wall structures in this maturation stage.
- The effect of NaCl reduction in the microbiological quality of cracked green table olives of the Macanilha Algarvia cultivarPublication . Mateus, Tânia; Santo, David; Saúde, Cíntia; Pires-Cabral, Paula; Quintas, CéliaThe present work aimed at studying the effect of the partial replacement of NaCl with KCl and CaCl2 of the fermenting brines on the microbiological quality of natural cracked green Macanilha Algarvia table olives. Olives were fermented in different salt combinations (Brine 1-8% NaCl, Brine 2-4% NaCl 4% KCl, Brine 3-4% NaCl 4% CaCl2, Brine 4-4% KCl 4% CaCl2, and Brine 5-2.7% NaCl 2.7% KCl 2.7% CaCl2) and the abundance of yeasts and enterobacteria was determined. At the end of fermentation, the main microbial safety parameters were evaluated. Samples were analyzed according to standard methodologies and using Chromocult Agar (coliforms and Escherichia colt). The yeasts collected were grouped by restriction analysis of the ITS-5.8S rRNA gene and identified by partial sequencing of the 26S rRNA. Throughout the study, a decrease of the enterobacteria population was observed in all the fermentations, which was greater and faster in brines containing potassium and calcium. The main yeasts identified were Pichia membranaefaciens, Candida boidinii, Zygosaccharomyces mrakii, Priceomyces carsonii, Saccharomyces cerevisiae, Wickerhamomyces anomalus and the yeast-like fungus Galactomyces geotrichum. The highest yeast diversity was found in olives produced in Brines 1, 2 and 3 and the lowest in Brines 4 and 5, where only the species P. membranaefaciens, C boidinii and G. geotrichum were identified. No Pseudomonas, E. coli, Salmonella, Staphylococcus aureus and Listeria monocytogenes were found in the table olives produced. (C) 2015 Elsevier B.V. All rights reserved.
- The effect of seasoning with herbs on the nutritional, safety and sensory properties of reduced-sodium fermented Cobrançosa cv. table olivesPublication . Pires-Cabral, Paula; Barros, Tânia; Mateus, Tânia; Prata, Jessica; Quintas, CéliaThis study aimed at evaluating the effectiveness of seasoning Cobrancosa table olives in a brine with aromatic ingredients, in order to mask the bitter taste given by KCl when added to reduced-sodium fermentation brines. Olives were fermented in two different salt combinations: Brine A, containing 8% NaCl and, Brine B, a reduced-sodium brine, containing 4% NaCl + 4% KCl. After the fermentation the olives were immersed in seasoning brines with NaCl (2%) and the aromatic herbs (thyme, oregano and calamintha), garlic and lemon. At the end of the fermentation and two weeks after seasoning, the physicochemical, nutritional, organoleptic, and microbiological parameters, were determined. The olives fermented in the reduced-sodium brines had half the sodium concentration, higher potassium and calcium content, a lower caloric level, but were considered, by a sensorial panel, more bitter than olives fermented in NaCl brine. Seasoned table olives, previously fermented in Brine A and Brine B, had no significant differences in the amounts of protein (1.23% or 1.11%), carbohydrates (1.0% or 0.66%), fat (20.0% or 20.5%) and dietary fiber (3.4% or 3.6%). Regarding mineral contents, the sodium-reduced fermented olives, presented one third of sodium, seven times more potassium and three times more calcium than the traditional olives fermented in 8% NaCl. Additionally, according to the panelists' evaluation, seasoning the olives fermented in 4% NaCl + 4% KCl, resulted in a decrease in bitterness and an improvement in the overall evaluation and flavor. Escherichia coli and Salmonella were not found in the olives produced.