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- Manufacturing of fermented goat milk with a mixed starter culture of Bifidobacterium animalis and Lactobacillus acidophilus in a controlled bioreactorPublication . Kongo, J. M.; Gomes, Ana M. P.; Malcata, F. XavierAims: This work was undertaken to study the feasibility and the characteristics of a fermented product made of goat milk, using a mixed starter culture of Bifidobacterium animalis and Lactobacillus acidophilus under controlled conditions, and to determine their survival in the fermented milk during refrigerated storage. Methods and Results: Goat milk was inoculated with Lact. acidophilus and Bif. animalis mixed starter, fermented in a glass bioreactor with controlled temperature (37 C) and anaerobiosis, and monitored for growth and acidification. The fermented milk was then stored for 10 days under refrigeration, and monitored daily for starter microflora survival and pH changes. Lact. acidophilus viable counts reached a maximum of 7Æ1 · 108 colony-forming units (CFU) ml)1, and Bif. animalis a maximum of 6Æ3 · 107 CFU ml)1 by 20 h of fermentation. During refrigerated storage, both strains exhibited a good survival, with viable numbers remaining essentially constant throughout the experiment, whereas the pH of the fermented milk dropped slightly. Conclusions: Mixed cultures of Bif. animalis and Lact. acidophilus may be used to produce fermented goat milk with high counts of both probiotic strains. Significance and Impact of the Study: Goat milk fermented with Bif. animalis and Lact. acidophilus can be manufactured as an alternative probiotic dairy product.
- Volatile and quality changes in fresh-cut cantaloupe and honeydew melons stored in modified atmosphere packagingPublication . Amaro, Ana L.; Beaulieu, John C.; Almeida, Domingos P. F.; Malcata, F. X.
- Separation of neutral lipid classes by high-performance liquid chromatography using light-scattering detection: analysis of vegetable oils and maize flourPublication . Rocha, João M.; Kalo, Paavo J.; Ollilainen, Velimatti; Malcata, F. Xavier
- Microbiological profile in sourdough: evolution during refrigerated storage.Publication . Rocha, João M.; Malcata, F. Xavier
- Antimicrobial Susceptibility of Enterococci Isolated from Terrincho CheesePublication . Pimentel, L. L.; Novais, C.; Pintado, M. E.; Gomes, Ana M. P.; Coque, T.; Sousa, J. C; Malcata, F. Xavier; Peixe, L.
- Microstructural, physicochemical and sensorial effects of pears (cv. Rocha) stored under controlled atmosphere conditionsPublication . Galvis-Sánchez, Andrea C.; Teixeira, Claudia; Fonseca, Susana C.; Malcata, F. Xavier
- Effects of addition of sucrose and salt, and of starvation upon thermotolerance and survival during storage of freeze-dried Lactobacillus delbrueckii ssp bulgaricusPublication . Carvalho, A. S.; Silva, J.; Ho, P.; Teixeira, P.; Malcata, F. X.; Gibbs, P.Increased survival of freeze-dried cells of Lactobacillus bulgaricus was observed when the drying medium was supplemented with sucrose; however, the magnitude of such protection was dependent on the growth medium used. Supplementing the growth medium with NaCl markedly increased survival of dried cells, and only a small effect was exerted by the composition of the drying medium or prior to starvation of cells. The D57 values of Lactobacillus bulgaricus cells grown in MRS were about half of those of cells grown in MRS supplemented with sucrose, with sucrose plus NaCl, or with NaCl.
- Review: Steam distilled spirits from fermented grape pomace Revision: Bebidas destiladas obtenidas de la fermentación del orujo de uvaPublication . Silva, M. L.; Macedo, A. C.; Malcata, F. X.Grape pomace is the solid residue left after juice extraction from grapes, and represents in Mediterra nean countries the most important by-product of the winemaking industry. Steam distillation of fer mented grape pomace will eventually produce a spirit, designated as bagaceira in Portugal, orujo in Spain and grappa in Italy. This paper comprehensively reviews fundamental and applied aspects of the manufacture of these spirits, encompassing their composition as well as metabolic reactions and microbial ecology that determine such composition during fermentation. These spirits adhere to maxi mum levels of methanol (potential toxic compound) and 2-butanol (potential flavor defect) fixed by EC regulations. Available studies pertaining to bagaceira, orujo and grappa have indicated that the final quality of these spirits depends strongly on the quality of the fresh grapes, the storage condi tions, and the distillation equipment and procedure employed.
- Determination of antioxidant capacity using the biological system bacteriophage P22/bacterium salmonella typhimuriumPublication . Gião, Maria S.; Borges, André B.; Guedes, Catarina J.; Hogg, Tim; Pintado, Manuela E.; Malcata, F. XavierBacteriophage/bacterium systems have been employed in the past in assays for virucidal activity. A novel application of one such system is proposed here for the in vivo determination of antioxidant capacity. It was shown that an antioxidant such as gallic acid can effectively protect against oxidative damage brought about by H2O2sbut only within a narrow range of concentrations (i.e., from 250 to 500 mg L-1); ascorbic acid, on the other hand, did not exhibit any protective effect against H2O2. Finally, neither ascorbic nor gallic acid demonstrated a virucidal effect. The P22/Salmonella typhimurium model system thus proved to be useful in the assessment of antioxidant capacity in vivo, at least using those two alternative model antioxidants.
- Hydrolysis of whey proteins by proteases extracted from Cynara cardunculus and immobilized onto highly activated supportsPublication . Lamasa, Estela M.; Barrosa, Rui M.; Balcão, Victor M.; Malcata, F. XavierBlends of cardosins A and B, enzymes present in aqueous extracts of the flowers of the thistle (Cynara cardunculus L.), have for long been used as rennets by the cheesemaking industry in the Iberian Peninsula. These dimeric proteases are present in the stigmæ and stylets of said flowers, and are thought to play a role in sexual reproduction of the plant. In the present research effort, production of cardosin derivatives (starting from a crude extract), encompassing full stabilization of their dimeric structure, has been attempted via covalent, multi-subunit immobilization onto highly activated agarose-glutaraldehyde supports. Boiling such enzyme derivatives in the presence of sodium dodecyl sulfate and β-mercaptoethanol did not lead to leaching of enzyme, thus proving the effectiveness of the attachment procedure. Furthermore, derivatives prepared under optimal conditions presented ca. half the specific activity of the enzyme in soluble form, and were successfully employed at lab-scale trials to perform (selective) hydrolysis of α-lactalbumin, one of the major proteins in bovine whey.