Effective microencapsulation of Enterococcus faecium in biopolymeric matrices using spray drying

Stability of probiotics through encapsulation: Comparative analysis of current methods and solutions

Probiotics have awakened a great interest in the scientific community for their potential beneficial effects on health. Although only allowed by the European Food Safety Agency as a nutrition declaration associated with the improvement of lactose digestion, recent in vitro and in vivo studies have demonstrated their varied beneficial effect for the improvement of certain pathologies. However, probiotics face stability and viability challenges, which make their delivery difficult in sufficient quantities for these effects to be observed. Thus, there is a dire need for the development and implantation of innovative technological protection procedures. In this sense, encapsulation rises as a widely applied technique, offering additional advantages. In the present study, a systematic review was conducted for the evaluation of the main encapsulation technologies applied in literature, considering operating conditions, probiotics, and encapsulation efficacy. For this purpose, several conditions are evaluated: a) the characteristics, storage conditions and viability of probiotics; b) evaluation and comparison of the probiotic stabilization for the main encapsulation methods; and c) co-encapsulation with potential bioactive molecules as a new alternative for improving cell viability. This evaluation revealed the efficacy of seven encapsulation techniques on the improvement of the stability and viability of probiotics.

Advances in spray-dried probiotic microcapsules for targeted delivery: a review

Probiotics have gained significant attention owing to their roles in regulating human health. Recently, spray drying has been considered as a promising technique to produce probiotic powders due to its advantages of high efficiency, cost-saving, and good powder properties. However, the severe environmental conditions from drying and digestion can significantly reduce cell viability, resulting in poor bioaccessibility and bioavailability of live cells. Therefore, there is a need to develop effective targeted delivery systems using spray drying to protect bacteria and to maintain their physiological functions in the targeted sites. This review highlights recent studies about spray-dried targeted delivery vehicles for probiotics, focusing on key strategies to protect bacteria when encountering external stresses, the formation mechanism of particles, the targeted release and colonization mechanisms of live cells in particles with different structures. Advances in the targeted delivery of live probiotics via spray-dried vehicles are still in their early stages. To increase the possibilities for industrialization and commercialization, functional improvement of microcapsules in terms of protection, targeted release, and colonization of bacteria, as well as the effect of spray drying on bacterial physiological functions in the host, need to be further investigated.

Microencapsulation of Yarrowia lipolytica: cell viability and application in vitro ruminant diets

Microencapsulation is an alternative to increase the survival capacity of microorganisms, including Yarrowia lipolytica, a widely studied yeast that produces high-value metabolites, such as lipids, aromatic compounds, biomass, lipases, and organic acids. Thus, the present study sought to investigate the effectiveness of different wall materials and the influence of the addition of salts on the microencapsulation of Y. lipolytica, evaluating yield, relationship with cell stability, ability to survive during storage, and in vitro application of ruminant diets. The spray drying process was performed via atomization, testing 11 different compositions using maltodextrin (MD), modified starch (MS) and whey protein concentrate (WPC), Y. lipolytica (Y. lipo) cells, tripolyphosphate (TPP), and sodium erythorbate (SE). The data show a reduction in the water activity value in all treatments. The highest encapsulation yield was found in treatments using MD + TPP + Y. lipo (84.0%) and WPC + TPP + Y. lipo (81.6%). Microencapsulated particles showed a survival rate ranging from 71.61 to 99.83% after 24 h. The treatments WPC + Y. lipo, WPC + SE + Y. lipo, WPC + TPP + Y. lipo, and MD + SE + Y. lipo remained stable for up to 105 days under storage conditions. The treatment WPC + SE + Y. lipo (microencapsulated yeast) was applied in the diet of ruminants due to the greater stability of cell survival. The comparison between the WPC + SE + Y. lipo treatment, wall materials, and the non-microencapsulated yeast showed that the microencapsulated yeast obtained a higher soluble fraction, degradability potential, and release of nutrients.

Kinetics and Mechanisms of Saccharomyces boulardii Release from Optimized Whey Protein-Agavin-Alginate Beads under Simulated Gastrointestinal Conditions

Encapsulation is a process in which a base material is encapsulated in a wall material that can protect it against external factors and/or improve its bioavailability. Among the different encapsulation techniques, ionic gelation stands out as being useful for thermolabile compounds. The aim of this work was to encapsulate Saccharomyces boulardii by ionic gelation using agavins (A) and whey protein (WP) as wall materials and to evaluate the morphostructural changes that occur during in vitro gastrointestinal digestion. Encapsulations at different levels of A and WP were analyzed using microscopic, spectroscopic and thermal techniques. Encapsulation efficiency and cell viability were evaluated. S. boulardii encapsulated at 5% A: 3.75% WP (AWB6) showed 88.5% cell survival after the simulated gastrointestinal digestion; the bead showed a significantly different microstructure from the controls. The mixture of A and WP increased in the survival of S. boulardii respect to those encapsulated with alginate, A or WP alone. The binary material mixture simultaneously allowed a controlled release of S. boulardii by mostly diffusive Fickian mechanisms and swelling. The cell-release time was found to control the increment of the Damköhler number when A and WP were substrates for S. boulardii, in this way allowing greater protection against gastrointestinal conditions.

Joint protection strategies for Saccharomyces boulardii: exogenous encapsulation and endogenous biofilm structure

Biofilms are heterogeneous structures composed of microorganisms and the surrounding extracellular polymeric substances (EPS) that protect the microbial cells from harsh environments. Saccharomyces boulardii is the first yeast classified as a probiotic strain with unique properties. However, tolerance of S. boulardii biofilms to harsh environments especially during production and in the gastrointestine remains unknown. In this study, S. boulardii cells were encapsulated in alginate microcapsules and subsequently cultured to form biofilms, and their survival and tolerance were evaluated. Microencapsulation provided S. boulardii a confined space that enhanced biofilm formation. The thick alginate shell and the mature biofilm improved the ability of S. boulardii to survive under harsh conditions. The exogenous encapsulation and the endogenous biofilm structure together enhanced the gastrointestinal tolerance and thermotolerance of S. boulardii. Besides, as the alginate shell became thinner with an increase in the subsequent culture duration, the EPS of S. boulardii biofilms exerted an important protective effect in resisting high temperatures. The encapsulated biofilm of S. boulardii after 24-h culture exhibited 60 × higher thermotolerance at 60 °C (10 min), while those after 6-h and 24-h culture showed 1000 × to 550,000 × higher thermotolerance at 120 °C (1 min) compared with the planktonic cells without encapsulation. The present study's findings suggest that a combination of encapsulation and biofilm mode efficiently enhanced gastrointestinal tolerance and thermotolerance of S. boulardii. KEY POINTS: • Encapsulated S. boulardii in biofilm mode showed enhanced tolerance. • Exogenous shell and endogenous biofilm provided dual protection to S. boulardii.