The Inoculation of Probiotics In Vivo Is a Challenge: Strategies to Improve Their Survival, to Avoid Unpleasant Changes, or to Enhance Their Performances in Beverages

Transcriptomic analysis reveals differential gene expression patterns of Lacticaseibacillus casei ATCC 393 in response to ultrasound stress

In recent years, there has been a growing interest in modulating the performance of probiotic, mainly Lactic Acid Bacteria (LAB), in the field of probiotic food. Attenuation, induced by sub-lethal stresses, delays the probiotic metabolism, and induces a metabolic shift as survival strategy. In this paper, RNA sequencing was used to uncover the transcriptional regulation in Lacticaseibacillus casei ATCC 393 after ultrasound-induced attenuation. Six (T) and 8 (ST) min of sonication induced a significant differential expression of 742 and 409 genes, respectively. We identified 198 up-regulated and 321 down-regulated genes in T, and similarly 321 up-regulated and 249 down-regulated in ST. These results revealed a strong defensive response at 6 min, followed by adaptation at 8 min. Ultrasound attenuation modified the expression of genes related to a series of crucial biomolecular processes including membrane transport, carbohydrate and purine metabolism, phage-related genes, and translation. Specifically, genes encoding PTS transporters and genes involved in the glycolytic pathway and pyruvate metabolism were up-regulated, indicating an increased need for energy supply, as also suggested by an increase in the transcription of purine biosynthetic genes. Instead, protein translation, a high-energy process, was inhibited with the down-regulation of ribosomal protein biosynthetic genes. Moreover, phage-related genes were down-regulated suggesting a tight transcriptional control on DNA structure. The observed phenomena highlight the cell need of ATP to cope with the multiple ultrasound stresses and the activation of processes to stabilize and preserve the DNA structure. Our work demonstrates that ultrasound has remarkable effects on the tested strain and elucidates the involvement of different pathways in its defensive stress-response and in the modification of its phenotype.

Probiotics in anthocyanin-rich fruit beverages: research and development for novel synbiotic products

Anthocyanin-rich fruit beverages are of special interest as functional products due to their antioxidant activity, antimicrobial properties against pathogens, and, more recently, evidence of prebiotic potential. The stability and bioactivity of anthocyanins, probiotics, prebiotics, and synbiotics have been extensively documented in beverage models and reviewed separately. This review summarizes the most recent works and methodologies used for the development of probiotic and synbiotic beverages based on anthocyanin-rich fruits with a synergistic perspective. Emphasis is made on key optimization factors and strategies that have allowed probiotic cultures to reach the minimum recommended doses to obtain health benefits at the end of the shelf life. The development of these beverages is limited by the high acidity and high content of phenolic compounds in anthocyanin-rich fruits. However, a proper selection of probiotic strains and strategies for their media adaptation may improve their viability in the beverages. Fermentation increases the viability of the probiotic cultures, improves the safety and stability of the product, and may increase its antioxidant capacity. Moreover, fermentation metabolites may synergistically enhance probiotic health benefits. On the other hand, the inoculation of probiotics without fermentation allows for synbiotic beverages with milder changes in terms of physicochemical and sensory attributes.

Probiotics in Functional Foods: Survival Assessment and Approaches for Improved Viability

Nowadays, food is no longer just for nutrition. Consumers are more demanding and expect to get health benefits from their daily meals. Various areas of the food industry are in great demand of functional chemicals to enhance the taste and nutritional value of their products. Probiotic bacteria have already been part of the human’s routine for good gut microbiota maintenance in terms of pharmaceutical products. Their incorporation in food however is a challenging task that offers great opportunities but has limitations as well. Specifically, the purpose of this review is to emphasize the importance of probiotics in food, to assess their survival through gastrointestinal tract, and to highlight the recent advances in approaches for their improved viability.

Selection of Lactic Acid Bacteria with In Vitro Probiotic-Related Characteristics from the Cactus Pilosocereus gounellei (A. Weber ex. K. Schum.) Bly. ex Rowl

Pilosocereus gounellei (A. Weber ex. K. Schum.) Bly. ex Rowl., popularly known as xique-xique, is a cactus from the Caatinga biome, which is rich in bioactive compounds but has not been previously studied as a source of lactic acid bacteria (LAB) with probiotic aptitudes. This study aimed to identify, characterize, and select LAB isolates with in vitro probiotic-related characteristics from xique-xique cladodes and fruit. Isolates with the most promising probiotic-related characteristics were evaluated regarding their in vitro technological properties and capability of surviving in chestnut milk, whey protein drink, and mate tea with mint during 21 days of refrigeration storage. Seventeen recovered isolates had typical characteristics of LAB. Six out of these seventeen LAB isolates passed the safety tests and were included in experiments to evaluate the in vitro probiotic-related characteristics. Based on the results of a principal component analysis, the isolates 69, 82, 98, and 108 had the best performances in experiments to evaluate the probiotic-related characteristics. In addition to showing good technological properties, the four selected LAB isolates had high viable counts (>7.3 log cfu/mL) and high sizes of physiologically active cell subpopulations in chestnut milk, whey protein drink, and mate tea during refrigeration storage. These four isolates were identified by 16S-rRNA sequencing as being Lacticaseibacillus paracasei or Lacticaseibacillus casei. The results indicate xique-xique as a source of potentially probiotic LAB isolates.

Wide World of Beverage Research: Reviews of Current Topics

In 2015, the journal Beverages (ISSN 2306-5710) was launched to provide insight into the beverage industry [...]

Synthetic reconstruction of extreme high hydrostatic pressure resistance in Escherichia coli

Although high hydrostatic pressure (HHP) is an interesting parameter to be applied in bioprocessing, its potential is currently limited by the lack of bacterial chassis capable of surviving and maintaining homeostasis under pressure. While several efforts have been made to genetically engineer microorganisms able to grow at sublethal pressures, there is little information for designing backgrounds that survive more extreme pressures. In this investigation, we analyzed the genome of an extreme HHP-resistant mutant of E. coli MG1655 (designated as DVL1), from which we identified four mutations (in the cra, cyaA, aceA and rpoD loci) causally linked to increased HHP resistance. Analysing the functional effect of these mutations we found that the coupled effect of downregulation of cAMP/CRP, Cra and the glyoxylate shunt activity, together with the upregulation of RpoH and RpoS activity, could mechanistically explain the increased HHP resistance of the mutant. Using combinations of three mutations, we could synthetically engineer E. coli strains able to comfortably survive pressures of 600-800 MPa, which could serve as genetic backgrounds for HHP-based biotechnological applications.

Probiotic and Antioxidant Potential of Lactobacillus reuteriLR12 and Lactobacillus lactisLL10 Isolated from Pineapple Puree and Quality Analysis of Pineapple-Flavored Goat Milk Yoghurt during Storage

In recent years, studies have focused on the therapeutic properties of probiotics to eliminate pathogenic microorganisms associated with various diseases. Lactobacilli are important probiotics groups that have been found to possess many health-promoting activities. This study was carried out to isolate LactobacillusreuteriLR12 and L. lactisLL10 from pineapple puree. The invitro analysis to evaluate probiotic characteristics of the isolated bacteria included survival in bile and acid tolerance. The cell-free supernatant of L. reuteri LR12 was effective against various pathogenic bacteria and fungi compared with L. lactisLL10. These two bacterial strains have strong anti-biofilm activity (100%) against Enterococcus faecalis, Staphylococcus aureus, and Bacillus cereus. The bacterial strains exhibited adhesion properties to HT-29 cells (human colorectal adenocarcinoma). These bacteria showed DPPH- (2,2-diphenyl-1-picryl-hydrazyl-hydrate) free radical scavenging activity, scavenging of hydroxyl radical activity, superoxide radical scavenging activity, and reducing power activity in the range of 72% ± 3%to 89.3% ± 1.7%, 64% ± 2.7%to 66.8% ± 1.5%, 59.8% ± 4.1% to 63.8% ± 2.1%, and 60.4% ± 1.8%to 66.1% ± 3.3%, respectively. Pineapple puree was used as the starter culture with milk for 2 days for yogurt preparation. Pineapple puree increased flavor and showed the physicochemical properties of yogurt. The finding of the sensory evaluation revealed no significant change compared with the control, except the appearance of yogurt. These findings show that Lactobacilli and pineapple puree have potential use in various probiotic preparations for the fermentation industry.

Ultrasound-Attenuated Microorganisms Inoculated in Vegetable Beverages: Effect of Strains, Temperature, Ultrasound and Storage Conditions on the Performances of the Treatment

Four microorganisms (Lactobacillus acidophilus LA5, Bifidobacterium animalis subsp. lactis DSM 10140 and Lactiplantibacillus plantarum c16 and c19) were attenuated through ultrasound (US) treatments (40% of power for 2, 4 and 6 min; and 60% for 2 min; pulses were set at 2 s) inoculated in rice–oats–almond–soy-based beverages and stored at 4 °C for eight days. All strains were able to survive throughout the storage independently by the food matrix. Concerning the effect on acidification, the results were analyzed through multifactorial analysis of variance (MANOVA) and the key-findings of this were: (i) The treatment with 40% of power for 6 min was the most efficient at delaying acidification; (ii) Lb. acidophilus LA5 showed the best capacity to delay acidification; (iii) in the soy-based beverage a lower acidification was found. In a second step, L. plantarum c16 and c19 were attenuated, inoculated in rice beverage, stored under a thermal abuse (for 4 and 24 h) and then at 4, 15 and 20 °C. The results showed that only when US were combined with refrigeration temperatures were they efficient at delaying acidification. Thus, a perspective for attenuation could be the optimization of the treatment to design an effective way to counteract acidification also under a thermal abuse.