Functional proteomics within the genus Lactobacillus

Producing Powders Containing Active Dry Probiotics With the Aid of Spray Drying

Probiotics are microorganisms capable of conferring health benefits to humans and animals when ingested. Probiotic products that prevail in food market usually contain viable bacteria from Lactobacillus and Bifidobacterium genera. Bacterial strains in these genera often have complex nutrient requirements and tend to be fragile under environmental stresses. How to incorporate the cells into food matrix without causing undesired viability loss is a key issue for developing products of viable probiotics. Spray drying offers a rapid way to produce powders encapsulating probiotics in a matrix of protectant(s), which may extend the term of viability preservation and expand the application of probiotic products. In spray drying, feed solution that contains probiotic cells and dissolved or suspended protectant solids are atomized into droplets, which are quickly converted into particles by drying in a hot airflow. The harsh conditions and interplaying stresses make the maintenance of cell viability a challenging task. To enhance cell survival in dried powders, various approaches have been attempted, including the enhancement of the intrinsic stress tolerance of cells, adjustment of protectant composition, and optimization of the production process and dryer settings. This chapter discusses important factors influencing probiotic viability during spray drying from aspects of microbiology, food chemistry, and drying process. The mechanisms underlying the influences at the droplet and cellular levels and strategies taken to protect cell viability at the process level are discussed.

pH-controlled fermentation in mild alkaline conditions enhances bioactive compounds and functional features of lentil to ameliorate metabolic disturbances

Lentil fermentation has a promising potential as a strategy for development of multifunctional ingredients targeting metabolic syndrome (MetS). Response surface methodology was applied to optimize lentil fermentation and study its effects on generation of peptides, soluble phenolics and bioactivities. Fermentation using Lactobacillus plantarum and Savinase® 16 L was carried out at different pH (6.5-8.5) and times (5.5-30 h). Analysis of variance was performed to evaluate linear, quadratic and interaction effects between fermentation parameters. pH positively affected peptides, soluble phenolic compounds and antioxidant activity whereas a negative impact on lipase inhibitory activity was observed (p < .0001). Time showed positive effect on proteolysis and negatively affected angiotensin I-converting enzyme inhibitory activity of fermented lentil (p < .0001). Multivariate optimization led to high levels of peptides, soluble phenolics and bioactivity of fermented lentil at pH 8.5 and 11.6 h. In conclusion, this study might contribute to the development of functional ingredients from lentil for MetS management.

Dietary Fibers and Protective Lactobacilli Drive Burrata Cheese Microbiome

This study was aimed at improving the functional attributes and shelf life of burrata cheese by using protective lactobacilli (Lactobacillus plantarum LPAL and Lactobacillus rhamnosus LRB), fructooligosaccharides, and inulin. Six burrata cheeses were made using (i) the traditional protocol (control), (ii) the addition of 0.5% fructooligosaccharides and inulin (DF cheese), (iii) protective lactobacilli in milk alone (PL cheese), (iv) protective lactobacilli in milk and governing liquid (2PL cheese), (v) protective lactobacilli in milk and dietary fibers (DF_PL cheese), and (vi) protective lactobacilli in milk and governing liquid and dietary fibers (DF_2PL cheese). As expected, DF, DF_PL, and DF_2PL cheeses showed 1.5% of total fibers. Burrata cheeses produced by adding protective lactobacilli only in milk (PL and DF_PL cheeses) showed the lowest acidification during cheese making and storage. Lactic and acetic acids and ethanol were found at the lowest concentrations in these samples. Analyses of cultivable microbiota and the microbiome showed that protective lactobacilli reduced the house microbiota components (e.g., Streptococcus thermophilus, Lactococcus lactis, and Leuconostoc lactis) during cheese making and storage. Protective lactobacilli slowed the growth of staphylococci, coliforms, and Pseudomonas spp., especially in early storage. According to the different microbiome assemblies, burrata samples differed in peptide profiles and the levels of free amino acids. As shown by a sensory analysis, the addition of protective lactobacilli in milk improved the flavor and increased the shelf life of burrata cheese. In comparison to cheeses made using protective cultures only in milk, the shelf lives of those containing cultures also in the governing liquid were not further prolonged and they received lower acceptability scores by the panelists.IMPORTANCE This study provides more in-depth knowledge of the microbiome of burrata cheese and the set-up for a novel biotechnology using prebiotic dietary fibers and protective probiotic Lactobacillus plantarum LPAL and Lactobacillus rhamnosus LRB in milk. The biotechnology proposed in this study should be considered a useful tool to improve the functional value of burrata cheese. The use of protective lactobacilli in milk enhanced the flavor formation and shelf life of burrata cheese.

Gene editing and genetic engineering approaches for advanced probiotics: A review

The applications of probiotics are significant and thus resulted in need of genome analysis of probiotic strains. Various omics methods and systems biology approaches enables us to understand and optimize the metabolic processes. These techniques have increased the researcher's attention towards gut microbiome and provided a new source for the revelation of uncharacterized biosynthetic pathways which enables novel metabolic engineering approaches. In recent years, the broad and quantitative analysis of modified strains relies on systems biology tools such as in silico design which are commonly used methods for improving strain performance. The genetic manipulation of probiotic microorganisms is crucial for defining their role in intestinal microbiota and exploring their beneficial properties. This review describes an overview of gene editing and systems biology approaches, highlighting the advent of omics methods which allows the study of new routes for studying probiotic bacteria. We have also summarized gene editing tools like TALEN, ZFNs and CRISPR-Cas that edits or cleave the specific target DNA. Furthermore, in this review an overview of proposed design of advanced customized probiotic is also hypothesized to improvise the probiotics.

Beneficial effects on host energy metabolism of short-chain fatty acids and vitamins produced by commensal and probiotic bacteria

The aim of this review is to summarize the effect in host energy metabolism of the production of B group vitamins and short chain fatty acids (SCFA) by commensal, food-grade and probiotic bacteria, which are also actors of the mammalian nutrition. The mechanisms of how these microbial end products, produced by these bacterial strains, act on energy metabolism will be discussed. We will show that these vitamins and SCFA producing bacteria could be used as tools to recover energy intakes by either optimizing ATP production from foods or by the fermentation of certain fibers in the gastrointestinal tract (GIT). Original data are also presented in this work where SCFA (acetate, butyrate and propionate) and B group vitamins (riboflavin, folate and thiamine) production was determined for selected probiotic bacteria.

Fermentation of Dietetic Fiber from Green Bean and Prickly Pear Shell by Pure and Mixture Culture of Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum 450B

The aim of this study was to evaluate the fermentation of dietary fiber from green bean (Phaseolus vulgaris) and prickly pear shell (Opuntia ficus-indica) by Lactobacillus acidophilus LA-5 and Bifidobacterium bifidum 450B growing as mono-culture and co-culture, the fermentation products, and proteins expressed during this process. The analysis of the fermentation profile showed a major growth of bacteria in the culture media of each dietary fiber supplemented with glucose, and particularly B. bifidum 450B at 48 h showed the highest growth. In the case of the co-culture, the growth was lower indicating the possible negative interaction between L. acidophilus LA-5 and B. bifidum 450B and may be due to the less amount of carbohydrates and the high content of non-soluble fiber that affected the nutrients availability for the bacterial strains. The pH changes indicated the presence of short-chain fatty acids (SCFAs), being acetate (46-100%) the main SCFA. Changes in the proteome concerned proteins that are involved in carbohydrate and other carbohydrate pathways. The characterization of the bacteria according to the growth, metabolites, and proteins expressed allows understanding the response to the change of environmental conditions and could be useful to understand L. acidophilus LA-5 and B. bifidum 450B strains' adaptation to specific applications.