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Cardoso Freitas Lopes de Freitas, Ana Cristina
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- Characterization of freezing effect upon stability of, probiotic loaded, calcium-alginate microparticlesPublication . Sousa, Sérgio; Gomes, Ana M.; Pintado, Maria M.; Silva, José P.; Costa, Paulo; Amaral, Maria H.; Duarte, Armando C.; Rodrigues, Dina; Rocha-Santos, Teresa A. P.; Freitas, Ana C.Microencapsulation, utilizing different techniques and polymers, has been studied with the objective of maintaining probiotic viability in food matrices, protecting the cells from their detrimental environment, storage conditions andthe passage of gastrointestinal tract (GIT). The main objective of this study was to assess the effect of freezing at−20◦C upon probiotic alginate-calcium microparticles’ integrity and functionality through parameters such as size,morphology and structure of microparticles as well as to assess cell resistance to simulated gastrointestinal tractconditions upon storage. In order to study the effect of freezing upon the stability of the microparticles, calcium-alginate microparticles, with or without probiotic cells (Lactobacillus casei-01, Lactobacillus paracasei L26, Lactobacillusacidophilus KI and Bifidobacterium animalis BB-12), were characterized at production time and after 60 days storage at−20◦C. An increase in particle size, loss of the spherical shape and porous net damages were observed after 60 daysof storage at −20◦C. In accordance, encapsulation in alginate was not able to exert protection to the encapsulatedprobiotic cells stored at −20◦C for 60 days, especially from acid and particularly bile salts. B. animalis BB-12 revealedto be the most resistant probiotic strain, to both the microencapsulation process and to GIT simulated conditions.
- Metabolic profiling of potential probiotic or synbiotic cheeses by nuclear magnetic resonance (NMR) spectroscopyPublication . Rodrigues, Dina; Santos, Claudio H.; Rocha-Santos, Teresa A. P.; Gomes, Ana M.; Goodfellow, Brian J.; Freitas, Ana C.To assess ripening of potential probiotic cheeses (containing either Lactobacillus casei-01 or Bifidobacterium lactis B94) or synbiotic cheeses with fructooligosaccharides (FOS) or a 50:50 mix of FOS/inulin, metabolic profiles have been obtained via classical biochemical analyses and by NMR spectroscopy. The addition of prebiotics to the cheeses resulted in lower proteolysis indices, especially in those synbiotic cheeses inoculated with B. lactis B94. Among synbiotic cheeses the combination of FOS and inulin resulted in an increase in lipolytic activity. The metabolic profiles of the cheeses analyzed by NMR spectroscopy, combined with multivariate statistics, allowed profiles to be distinguished by maturation time, added probiotic bacteria, or, in the case of B. lactis B94 cheese, added prebiotic. The NMR results are in agreement with the biochemical analyses and demonstrate the potential of NMR for the study of metabolic processes in probiotic/synbiotic food matrices.