Effective encapsulation of reuterin-producing Limosilactobacillus reuteri in alginate beads prepared with different mucilages/gums.

The mainly aim of this study was to use mucilaginous solutions obtained from tamarind, mutamba, cassia tora, psyllium and konjac powdered to encapsulate reuterin-producing Limosilactobacillus reuteri in alginate beads by extrusion technique. In the particles were determined the bacterial encapsulation efficiency, cell viability during storage and survival under simulated gastric and intestinal conditions. Moreover, the reuterin production, its entrapment into the beads and the influence on viability of encapsulated microorganism were evaluated. Scanning electron microscopy and Fourier Transform Infrared spectroscopy were employed to characterize the produced particles. The beads showed a relatively spherical shape with homogenous distribution of L. reuteri. The use of gums and mucilages combined with alginate improved the encapsulation efficiency (from 93.2 to 97.4%), the viability of encapsulated bacteria during refrigerated storage (especially in prolonged storage of 20, 30 and 60 days) and the survival after exposure to gastric and enteric environments (from 67.7 to 76.6%). The L. reuteri was able to produce reuterin via bioconversion of glycerol in the film-forming solutions, and the entrapment of the metabolite was improved using konjac, mutamba and tamarind mucilaginous solutions in the encapsulation process (45, 44.57 and 41.25%, respectively). Thus, our findings confirm the great potential of these hydrocolloids to different further purposes, enabling its application as support material for delivery of chemical or biological compounds.

Reuterin-producing Limosilactobacillus reuteri: Optimization of in situ reuterin production in alginate-based filmogenic solutions.

Limosilactobacillus reuteri produces reuterin via glycerol anaerobic fermentation. This compound has antimicrobial properties and is used for food preservation purposes. Filmogenic solutions constituted of polysaccharides and glycerol are also employed, however, reuterin synthesis in filmogenic solutions has not yet been reported. Thus, the aim of this study was to optimize the in situ reuterin production by L. reuteri in alginate- and glycerol based-filmogenic solution, evaluating the survival of reuterin-producing bacteria during fermentation. The study consisted of a completely randomized design employing two L. reuteri strains (DSM 20016 and DSM 17938). The filmogenic solutions were obtained using sodium alginate (20 g/L) and two independent variables were studied: glycerol (0-300 mmol/L) and initial biomass of L. reuteri (≅6, 7, and 8 log CFU/mL). The samples were analyzed every 24 h for 72 h of anaerobic fermentation (37 °C). Both L. reuteri strains confirmed the potential for reuterin production and were susceptible to the metabolite produced. The highest reuterin production was achieved using L. reuteri DSM 20016. The initial microbial biomass of 8 log CFU/mL and 100 mmol/L of glycerol increased the reuterin production. However, higher conversion yields from glycerol to reuterin were obtained using 50 mmol/L of substrate.

Encapsulation of Bifidobacterium BB12® in alginate-jaboticaba peel blend increases encapsulation efficiency and bacterial survival under adverse conditions.

Most foods with probiotics claims are associated to dairy products, whose consumption is restricted to part of the population, creating a favorable scenario for the development of probiotic foods in alternative matrices. However, the development of probiotic foods in non-dairy matrices is still a technological challenge, since the foods intrinsic parameters can cause injuries to microorganisms. An alternative to protect the microbial cells in adverse environments involves encapsulation. Therefore, the objective of this study was to evaluate the influence of alginate-jaboticaba peel blend in the improvement of encapsulation efficiency, viability maintenance, and cell survival of Bifidobacterium BB12® under simulated gastrointestinal digestion and after incorporating in traditional jaboticaba jam. The particles were obtained by ion gelling technique using alginate with or without powdered jaboticaba peel. The addition of jaboticaba peel in particles improved encapsulation efficiency (> 90%) and resulted in higher cell survival in simulated gastrointestinal digestion. During storage in jam, the loss in cell viability was approximately constant: c.a. 0.5 log CFU/g/day for encapsulated cells and c.a. 1.0 log CFU/g/day for free cells. These results suggest that use of alginate and powdered jaboticaba peel blend is a promising approach to protect Bifidobacterium BB12® against adverse environments, such as non-dairy food matrices. KEY POINTS: • Powdered jaboticaba peel increased the encapsulation efficiency in alginate particles. • Encapsulation improved cell survival under adverse conditions. • Useful approach for the development of non-conventional probiotic products. Graphical abstract.

Encapsulated probiotic cells: Relevant techniques, natural sources as encapsulating materials and food applications - A narrative review.

The administration of probiotic microorganisms in adequate amounts is constantly related to health benefits. To promote beneficial effects, these microorganisms must not be affected by exposure to environmental factors and must be able to adhere and colonize the human gastrointestinal tract. Several encapsulation techniques and encapsulating materials are available to produce probiotic particles, however, it is essential that the process must not be aggressive, reducing or preventing injuries and cell losses, besides, the particle properties obtained must be adequate for the proposed purpose. At the same time, the global market for supplements and probiotic foods has been growing significantly, and cell encapsulation appears as an alternative to incorporate probiotics into different food matrices. This review discusses and updates the main techniques, and the traditional and emerging polysaccharides for encapsulation of probiotic cells, as well as the advantages and possibilities of incorporating produced particles into food matrices. Currently, various scientific studies report the use of different encapsulation techniques, such as extrusion, emulsion, spray drying, spray chilling and fluidized bed to encapsulate probiotics properly. The alginate is still widely used to produce probiotic particles, however, there has been a growing interest in its total or partial substitution with others polysaccharides, such as gums, mucilages, prebiotic compounds and microbial exopolysaccharides, which improve the protection and survival of encapsulated cells and allow their incorporation into dairy and non-dairy food products.

[Molecular characterisation of a kindred with MEN2A and clinical implications]. / Caracterização molecular de uma família com nem2a e suas implicações clínicas.

INTRODUCTION: MEN2A is an autossomal dominant cancer syndrome characterised by the presence of medullary thyroid cancer, pheochromocytoma and primary hyperparathyroidism. Germline mutations of the RET protooncogene constitute the molecular defect and can be identified in affected individuals. Genetic screening of family members at risk allows early diagnosis and preventive measures before the appearance of the disease. We present a family with several members affected with MEN2A, their molecular characterisation and the clinical implications of genetic testing. POPULATION AND METHODS: We studied 18 members distributed among three generations of a family of which four members were clinically affected with MEN2A and cutaneous lichen amyloidosis. RET gene mutations were screened for in affected individuals and their offspring by PCR-RFLP techniques. RESULTS: Genetic testing revealed a point mutation at codon 634 (TGC>TGG), in the heterozygous state, in all affected individuals. The same mutation was also found in a five years old asymptomatic child which after total thyroidectomy showed to have multifocal medullary thyroid carcinoma. DISCUSSION: Genetic screening is the most suitable method for pre-symptomatic diagnosis of MEN2A allowing an efficient and early identification of individuals who will later develop the disease. These can be monitored more closely and be submitted to a prophylactic thyroidectomy before the appearance of medullary thyroid carcinoma. The ideal moment for this intervention is still under discussion although the results of this study suggest that it should be undertaken before the age of five.