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- Interrelationships among microbiological, physicochemical, and biochemical properties of Terrincho cheese, with emphasis on biogenic aminesPublication . Pinho, Olivia; Pintado, Ana I. E.; Gomes, Ana M. P.; Pintado, M. E.; Malcata, F. Xavier; Ferreira, Isabel M. P. L. V. O.Changes in the microbiological, physicochemical, and biochemical characteristics of Terrincho cheese as represented by native microflora, pH, water activity, soluble nitrogen fractions, free amino acids, and biogenic amines (e.g., ethylamine, dimethylamine, tryptamine, phenylethylamine, putrescine, cadaverine, histamine, tyramine, cystamine, and spermine) during ripening were monitored. Terrincho is a traditional Portuguese cheese manufactured from raw ewe's milk. The main groups of microorganisms (lactococci, lactobacilli, enterococci, pseudomonads, staphylococci, coliforms, yeasts, and molds) were determined following conventional microbiological procedures. Free amino acids and biogenic amines were determined by reverse-phase high-performance liquid chromatography, following extraction from the cheese matrix and derivatization with dabsyl chloride. The total content of free amino acids ranged from 1,730 mg/kg of dry matter at the beginning of the ripening stage to 5,180 mg/kg of dry matter by day 60 of ripening; such an increase was highly correlated with the increase of watersoluble nitrogen in total nitrogen, 12% trichloroacetic acid–soluble nitrogen in total nitrogen, and 5% phosphotungstic acid– soluble nitrogen in total nitrogen throughout ripening. Histamine was consistently present at very low levels, whereas putrescine, cadaverine, and tryptamine were the dominant biogenic amines and increased in concentration during ripening. Ethylamine, tryptamine, phenylethylamine, and cystamine reached maxima by 30 days of ripening and decreased thereafter. Significant correlations between amino acid precursors and corresponding biogenic amines, as well as between biogenic amines and microbial viable numbers, were observed.
- Consumer acceptance and sensory profiling of reengineered kitoza productsPublication . Pintado, Ana I. E.; Monteiro, Maria João; Talon, Régine; Leroy, Sabine; Scislowski, Valérie; Fliedel, Geneviève; Rakoto, Danielle; Maraval, Isabelle; Costa, Ana I. A.; Silva, Ana P.; Pallet, Dominique; Tomlins, Keith; Pintado, M. E.Kitoza refers to a traditional way of preparing beef and pork in Madagascar. However, in order to improve some drawbacks previous identified, the product was submitted to a reengineering process. The acceptance and sensory profiling of improved Kitoza products among Portuguese consumers was investigated. A local smoked loin sausage was selected as basis for comparison. Firstly, a Focus Group study was performed to identify sensory descriptors for Kitoza products and explore product perception. Subsequently, a Flash Profile and a consumer sensory acceptance study were conducted. Flash Profile's results showed that beef- and pork-based Kitoza products investigated differed considerably in all sensory dimensions. The Portuguese sausage was characterized as having a more intense and lasting after taste, as well as displaying a higher degree of (meat) doneness. The acceptance study yielded higher overall liking ratings for pork- than for beef-based Kitoza, although the Portuguese sausage remained the most appreciated product.
- Acidifying and aromatic properties of enterococcus strains in ovine and bovine milksPublication . Pimentel, L. L.; Soares, J. C.; Pintado, M. E.; Pintado, Ana I. E.; Gomes, Ana M. P.; Ferreira, A. C.; Malcata, F. X.
- Production of polysaccharide by Rahnella aquatilis with whey feedstockPublication . Pintado, M. E.; Pintado, Ana I. E.; Malcata, F. X.The rates were monitored on biomass increase, polysaccharide production and viscosity development of whey broth and a control synthetic broth during fermentation by Rahnella aquatilis and organic acids, lactose, peptides and free amino acids were measured. Growth curves were similar and characterized by maximum specific growth rates of 0.61 h−1 for whey and 0.63 h−1 for synthetic medium. The yields of polysaccharide were 0.59 g/glactose for the synthetic medium and 0.56 for whey. Small peptides (<4,000 Da) and most free amino acids in both fermentation media were consumed within 24h.
- Probiotic Properties of Enterococci – Survival in simulated gastric juice and with bile saltsPublication . Pimentel, Lígia L.; Pintado, M. E.; Pintado, Ana I. E.; Gomes, Ana M. P.; Malcata, F. Xavier
- Microbiological, biochemical and biogenic amine profiles of Terrincho cheese manufactured in several dairy farmsPublication . Pintado, Ana I. E.; Pinho, Olívia; Ferreira, Isabel M. P. L. V. O.; Pintado, M. E.; Gomes, Ana M. P.Terrincho is a Portuguese traditional cheese, bearing a protected denomination of origin (PDO) status, which is manufactured from raw ewes’ milk and ripened for a minimum period of 30 d. The objectives of this research effort were to characterize the microbiological and biochemical profiles of this cheese, manufactured in several dairy farms during the winter cheesemaking season (December through March), and establish tentative correlations between these profiles and formation of biogenic amines. For this goal, 29 cheeses from five batches, manufactured in as many dairy farms located throughout the PDO region, were analysed. The viable numbers of the total (mesophilic) microflora, enterococci, lactococci, lactobacilli, enterobacteria, staphylococci, pseudomonads, yeasts and moulds were determined by 30 d, following classical plate counting on specific media. Free amino acid and biogenic amine contents were determined by reverse-phase high-pressure liquid chromatography. The concentration of biogenic amines correlated well with microbial viable numbers, in both qualitative and quantitative terms; significant correlations were observed between enterococci and phenylethylamine (r ¼ 0.868, po0.0001), and between lactococci and cadaverine (r = 0.646, p <0.002) and tyramine (r = 0.868, p<0.0001). On the other hand, 220 g of Terrincho cheese would have to be consumed at a given time if the threshold of worst case risk was to be attained, which appears unrealistic for a typically single-doses meal ingredient. This study has contributed to deepen the knowledge on the microbiological and biochemical features of a unique Portuguese cheese throughout ripening, and to rationalize its safe consumption in terms of biogenic amines.
- Rheological characterization under shear of a fraction of polymer produced via fermentation of whey-related media by Rahnella aquatilisPublication . Pintado, M. E.; Silva, J. A. Lopes da; Pintado, Ana I. E.; Malcata, F. XavierProduction of lactan, a polysaccharide composed of mannose, galactose and galacturonic acid (at the ratio of 5:3:2), starting from a semidefined medium containing lactose via fermentation with Rahnella aquatilis was described previously. In this communication, such polysaccharide was produced from five alternative fermentation media: (1) a synthetic (defined) medium, plain whey (under (2) aerobic and (3) anaerobic conditions), (4) whey permeate and (5) whey with 2% NaCl (w/v). The effect of the concentration of polysaccharide, pH and ionic strength at harvest on the rheological properties of the polysaccharide was studied using lactan-enriched fractions recovered from each medium and analysed in solution under steady shear flow. Lactan solutions showed a shear-thinning behaviour in all cases, and increases in viscosity were observed at increasing concentrations of polysaccharide, as expected. The polysaccharide fraction produced from whey with 2% (w/v) NaCl and plain whey under anaerobic conditions exhibited lower viscosity than that produced from the other media, an observation that is associated with the lower concentration of polysaccharide. Post-harvest addition of salts (KCl or CaCl2) and changes in pH (3–11) affected slightly the viscosity of the polysaccharide solutions. q1998
- Recuperación y revalorización del lactosuero para la producción de nuevos produtos con propriedades funcionalesPublication . Madureira, A. R.; Pintado, Ana I. E.; Gomes, Ana M. P.; Malcata, F. X.; Pintado, M. E.En los últimos años han surgido gran cantidad de alimentos funcionales a los que se les atribuyen diversas propiedades beneficiosas. Entre estos alimentos se encuentran aquellos que contienen proteínas del lactosuero así como aquellos que incorporan bacterias probióticas en su composición. En la actualidad existen matrices de proteínas de suero que contienen bacterias probióticas que se mantienen viables durante 28 días a temperaturas de refrigeración. Además, también se han realizado diferentes estudios relacionados con la actividad metabólica, las propiedades antimicrobianas y la resistencia a las enzimas del tracto gastrointestinal. Por último, se ha evaluado el uso de cepas de bacterias del ácido láctico con propiedades probióticas en la producción de exopolisacáridos en lactosuero.