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Cardoso Freitas Lopes de Freitas, Ana Cristina
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- Nanoprobiotics: when technology meets gut healthPublication . Machado, Daniela; Almeida, Diana; Seabra, Catarina Leal; Andrade, José Carlos; Gomes, Ana Maria; Freitas, Ana CristinaNanotechnology is a fast-rising industry not defined by a single field of research, but as the convergence of disciplines, such as chemistry, biology, physics, mathematics, and engineering, which exploits the benefits of nanoscale dimensions and characteristics for application in the macroworld. Current applications vary widely from nanorobotic industry to simple household items. However, the combination of such phenomena with probiotic science, another emerging and potentially promising area for the prevention and treatment of several human gastrointestinal and extraintestinal disorders using beneficial microorganisms, gives birth to “nanoprobiotics,” a field that focuses on the application of nanoscience into the probiotic-related world. In this chapter, we will navigate through the basic nanotech and probiotic knowledge and the current technologies employed with success for probiotic delivery and, ultimately, discuss what possibilities lie ahead in the nanoprobiotic future.
- Encapsulation of probiotic strains in plain or cysteine-supplemented alginate improves viability at storage below freezing temperaturesPublication . Sousa, Sérgio; Gomes, Ana M.; Pintado, Maria M.; Malcata, Francisco X.; Silva, José P.; Sousa, José M.; Costa, Paulo; Amaral, Maria H.; Rodrigues, Dina; Rocha-Santos, Teresa A. P.; Freitas, Ana C.Four probiotic bacteria (Lactobacillus paracasei L26, L. casei-01, L. acidophilus Ki, and Bifidobacterium animalis BB-12 R ) were encapsulated in plain alginate or alginate supplemented with L-cysteine·HCl, and resulting microcapsules were stored at different temperatures, namely 21, 4, −20, or −80◦C for a period of up to6months. The results showed that the encapsulation in calcium alginate microcapsules was only effective in promoting protection at freezing temperatures, independently of the sensitivity of the strain. Storage of calcium alginate microcapsules at −80◦C indicated a protective effect upon viability of all four probiotic strains and the presence of L-cysteine·HCl in the alginate matrix improved protection upon cell viability of B. animalis BB-12 R . An increase in storage temperature of encapsulated bacteria caused an increase in rate of loss in their viability that was strain dependent. This study suggests that microencapsulation of probiotic cells in calcium alginate can be suitable for sustaining the viability of probiotics in food products that require storage below freezing temperatures, even in the absence of cryoprotectors, contributing to an increased shelf life.
- 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.
- Storage Stability of Lactobacillus paracasei as Free Cells or Encapsulated in Alginate-Based Microcapsules in Low pH Fruit JuicesPublication . Rodrigues, Dina; Sousa, Sérgio; Gomes, Ana M.; Pintado, Maria M.; Silva, José P.; Costa, Paulo; Amaral, Maria H.; Rocha-Santos, Teresa; Freitas, Ana C.The main objective of this research effort was to study whether microencapsulation could be a viable alternative to obtain probiotic orange or peach juices. In order to be considered probiotic food, probiotic bacteria must be present in sufficient viable numbers to promote a benefit to the host. The survival and viability of Lactobacillus paracasei L26 in juices over 50 days of storage at 5°C was assessed, evaluating the potential use of encapsulated cells in alginate microcapsules. L. paracasei L26 demonstrated good viability in both orange and peach juices despite the low pH values of both juices. Microencapsulation in alginate, with or without double coating, revealed to be suitable to protect L. paracasei L26 since viable cells were approximately 9 log cfu/g after 50 days of storage at 5°C. In general, the probiotic fruit juices showed a decrease in pH during storage. Glucose and fructose contents as well as citric acid contents decreased during storage, whereas an increase in formic acid was observed. The outcome of this study points to L. paracasei L26 as having promising potential, especially in an encapsulated form, as functional supplements in fruit juices without dairy ingredients due to their tolerance in an acidic environment over 50 days of storage at 5°C. Further studies are warranted to prove the functionality of juices with encapsulated probiotic strains.