Effect of Non-Dairy Food Matrices on the Survival of Probiotic Bacteria during Storage

The Potential of Bacillus Species as Probiotics in the Food Industry: A Review

The demand for probiotics is increasing, providing opportunities for food and beverage products to incorporate and market these foods as a source of additional benefits. The most commonly used probiotics belong to the genera of Lactobacillus and Bifidobacterium, and traditionally these bacteria have been incorporated into dairy products, where they have a wider history and can readily survive. More recently, there has been a desire to incorporate probiotics into various food products, including baked goods. In recent years, interest in the use of Bacillus species as probiotics has greatly increased. The spores of various Bacillus species such as Bacillus coagulans and Bacillus subtilis, have significantly improved viability and stability under harsher conditions during heat processing. These characteristics make them very valuable as probiotics. In this review, factors that could affect the stability of Bacillus probiotics in food products are highlighted. Additionally, this review features the existing research and food products that use Bacillus probiotics, as well as future research opportunities.

Selection of a Probiotic for Its Potential for Developing a Synbiotic Peach and Grape Juice

Due to recent interest in the potential of probiotics as health promoters and the impact of health and environmental concerns on eating habits, non-dairy probiotic food products are required. This study aimed to evaluate the viability of different probiotic microorganisms in peach and grape juice (PGJ) with or without the prebiotic inulin and their antimicrobial activity against the foodborne pathogen Listeria monocytogenes and the juice spoilage microorganism Saccharomyces cerevisiae. Firstly, the viability of seven probiotic strains was studied in PGJ with an initial concentration of 107 CFU/mL for 21 days at 4 °C and for 3 days at 37 °C. In parallel, the physicochemical effect, the antimicrobial effect and the lactic acid production in PGJ were evaluated. Secondly, the probiotic with the best viability results was selected to study its antimicrobial effect against L. monocytogenes and S. cerevisiae, as well as ethanol and acetaldehyde production by the latter. L. casei showed the highest viability and grew in both refrigerated and fermentation conditions (1 log), produced the greatest lactic acid (5.12 g/L) and demonstrated in vitro anti-Listeria activity. Although the addition of the prebiotic did not improve the viability, lactic acid production or anti-Listeria activity of the probiotics, under the conditions studied, the prebiotic potential of inulin, support the design of a synbiotic juice. Finally, although none of the probiotic, fermentation products, or postbiotics showed any antimicrobial activity against L. monocytogenes or S. cerevisiae, the addition of L. casei to the PGJ significantly reduced the production of S. cerevisiae metabolite ethanol (29%) and acetaldehyde (50%). L. casei might be a suitable probiotic to deliver a safe and functional PGJ, although further research should be carried out to determine the effect of the probiotic and fermentation on the nutritional profile of PGJ.

Mathematical Modeling and Optimization of Lactobacillus Species Single and Co-Culture Fermentation Processes in Wheat and Soy Dough Mixtures

To improve food production via fermentation with co-cultures of microorganisms (e.g., multiple lactic acid bacteria-LAB strains), one must fully understand their metabolism and interaction patterns in various conditions. For example, LAB can bring added quality to bread by releasing several bioactive compounds when adding soy flour to wheat flour, thus revealing the great potential for functional food development. In the present work, the fermentation of three soy and wheat flour mixtures is studied using single cultures and co-cultures of Lactobacillus plantarum and Lactobacillus casei. Bio-chemical processes often require a significant amount of time to obtain the optimal amount of final product; creating a mathematical model can gain important information and aids in the optimization of the process. Consequently, mathematical modeling is used to optimize the fermentation process by following these LAB’s growth kinetics and viability. The present work uses both multiple regression and artificial neural networks (ANN) to obtain the necessary mathematical model, useful in both prediction and process optimization. The main objective is to find a model with optimal performances, evaluated using an ANOVA test. To validate each obtained model, the simulation results are compared with the experimental data.

Research of the survival of a consortium of Zygosaccharomyces kombuchaensis yeast and Gluconoacetobacter xylinus bacteria during frozen storage using various protective media

In the present study the survival of the consortium of yeast and bacteria using protective media was investigated. The protective medium consisting of 1 % gelatin, 5 % monosodium glutamate and 5 % sucrose provides the best preservation of living cells of the consortium and allows stabilization of cells for up to 100 days at storage temperatures from -2 °C to -10 °C. The projective medium consisting of 1 % gelatin and 10 % sucrose provides effective storage of the cells at t=-2 °C for 100 days; t=-5 °C – 80 days; t=-10 °C – 60 days. The projective medium of skimmed milk and 7.5 % glucose ensures effective storage of the cells of the consortium at t=-2 °C for 100 days; t=-5 °C – 80 days; t=-10 °C – 80 days. The information obtained is interesting for following researches of the development of technologies for the bioconversion of plant materials.

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.

Impact of cultivation strategy, freeze-drying process, and storage conditions on survival, membrane integrity, and inactivation kinetics of Bifidobacterium longum

Bifidobacterium longum, one of the main microorganisms in the human gut, is used as an adjunct to lactic acid starter cultures or sold as a probiotic product. Therefore, Bifidobacterium longum cell suspensions get freeze-dried with protective additives to prevent activity losses. To date, investigations covering growth and inactivation kinetics of Bifidobacterium longum during the whole process (cultivation, drying, and storage) have been lacking. In this study, the effect of cultivation conditions and shelf temperature as well as the influence of protectants (maltodextrin, glucitol, trehalose) at various concentrations on cell survival during freeze-drying was assessed. Drying was followed by a storage at + 4 °C and + 20 °C for 70 days to evaluate inactivation kinetics. The impact of the different factors was assessed by measuring surival rate and residual moisture content at various points of time over the whole process. In parallel cell membrane integrity and glass transition were determined to reveal inactivation effects. Cultivation strategy had a strong influence on survival with a huge potential for process improvement. A pH of 6.0 at the growth optimum of the strain provides better conditions regarding cell survival after drying than free acidification (non-regulated pH conditions). During the drying step, membrane leakage due to the removal of water is the main reason for the inactivation in this process step. In this study, the highest survival of 49% was obtained with cells dried at + 35 °C shelf temperature with an addition of maltodextrin (75% bacterial dry matter, w/w). The results show that Bifidobacterium longum cells are mostly inactivated during drying, whereas storage conditions at + 4 °C with an addition of 75% BDM maltodextrin relative to bacterial dry mass prevent cell loss completely.

Technological variables influencing the growth and stability of a silage inoculant based on spray-dried lactic acid bacteria

AIMS

To investigate the influence of different culture media and fermentation conditions on growth performance and viability of three lactic acid bacteria (LAB) strains with potential as silage inoculants, and to optimize spray-drying in order to enhance survival to dehydration and storage stability.

METHODS AND RESULTS

In house-formulated MRS was a suitable low-cost culture medium for Lactobacillus plantarum Hv75, Pediococcus acidilactici 3903 and L. buchneri B463. Uncontrolled pH biomass production conferred enhanced stability during storage at 4°C after spray-drying. The use of whey protein concentrate 35 (WPC)-maltodextrin (M) as matrix, inlet temperature of 145-150°C and air flow rate of 601 l h^-1 was adequate for the production of dehydrated LAB. According to the desirability function, at this optimized condition, moisture content, yield and solubility were predicted to be 3·96, 73·68 and 90·36% respectively. Those conditions also showed a decrease of 0·855 log CFU per gram after drying, no loss in viability at 4°C for 6 months and 1 log CFU per gram reduction at 25°C.

CONCLUSIONS

Stable and economically feasible dehydrated LAB cultures were obtained using alternative culture media, fermentation under uncontrolled pH and optimizing spray-drying process conditions through the desirability function method.

SIGNIFICANCE AND IMPACT OF THE STUDY

Our results can be utilized for efficient production and commercialization of several dry LAB.

Viability assessment of Bifidobacterium longum ATCC 15707 on non-dairy foods using quantitative fluorescence microscopy

This study demonstrates an effective technique for separating and purifying viable bacteria from samples that interfere with viability staining. The viability of Bifidobacterium longum ATCC 15707 was assessed using Percoll Buoyant Density Gradient Centrifugation (PBDC) to separate bacteria from complex non-dairy food matrices and Quantitative Fluorescence Microscopy (QFM) to determine individual cells using LIVE/DEAD BacLight bacterial viability staining. Water agar (3%) was used to retain cells of B. longum and offered a lower fluorescence background with BacLight viability staining, compared with fixation on polycarbonate (PC) black membrane. The effect of drying temperatures and non-dairy foods on viability of B. longum was assessed. B. longum coated on oat, peanut or raisin was separated by filtration, low- and high-speed centrifugation, flotation and sedimentation buoyant density centrifugation. Purified cells were subsequently deposited on water agar for rehydration followed by LIVE/DEAD BacLight viability staining and enumeration. Conventional plate counting was also conducted to compare viability results. Finally, this method was applied to assess cell membrane damages of B. longum incorporated onto non-dairy foods during 24 h drying. Furthermore, viability assessment of B. longum coated onto oat, peanut, or raisin was much lower by plate counting compared to viability staining. Drying appeared to have a greater impact when viability was assessed by plate counting compared to viability staining. IMPORTANCE: Enumeration of viable beneficial bacteria from function foods presents a significant bottleneck for product development and quality control. Interference with microscopic and/or fluorescent techniques by ingredients, time required to incubate plated microbes, and the transient nature of the colony forming unit make rapid assessment of viable bacteria difficult. Viability assessment of Bifidobacterium longum ATCC 15707 by Percoll Buoyant Density Gradient Centrifugation with LIVE/DEAD BacLight viability staining on water agar (3%) was in agreement with serial dilution enumeration. Without the need for incubation viability assessment by staining provided a more rapid means to assess the impact of drying on the viability of B. longum coated onto oat, peanut or raisin.

Optimization of Production Parameters for Probiotic Lactobacillus Strains as Feed Additive

In animal nutrition, probiotics are considered as desirable alternatives to antibiotic growth promoters. The beneficial effects of probiotics primarily depend on their viability in feed, which demands technical optimization of biomass production, since processing and storage capacities are often strain-specific. In this study, we optimized the production parameters for two broiler-derived probiotic lactobacilli (L. salivarius and L. agilis). Carbohydrate utilization of both strains was determined and preferred substrates that boosted biomass production in lab-scale fermentations were selected. The strains showed good aerobic tolerance, which resulted in easier scale-up production. For the freeze-drying process, the response surface methodology was applied to optimize the composition of cryoprotective media. A quadratic polynomial model was built to study three protective factors (skim milk, sucrose, and trehalose) and to predict the optimal working conditions for maximum viability. The optimal combination of protectants was 0.14g/mL skim milk/ 0.08 g/mL sucrose/ 0.09 g/mL trehalose (L. salivarius) and 0.15g/mL skim milk/ 0.08 g/mL sucrose/ 0.07 g/mL (L. agilis), respectively. Furthermore, the in-feed stabilities of the probiotic strains were evaluated under different conditions. Our results indicate that the chosen protectants exerted an extensive protection on strains during the storage. Although only storage of the strains at 4 °C retained the maximum stability of both Lactobacillus strains, the employed protectant matrix showed promising results at room temperature.

Cocoa Pulp as Alternative Food Matrix for Probiotic Delivery

BACKGROUND

For screening probiotic strains with viability and stability in non-dairy foods for health benefits, we revised all patents relating to probiotics in food.

OBJECTIVE

Screening of potential probiotics from Brazilian Minas artisanal cheese and verify their survival in frozen Brazilian cocoa pulp.

METHODS

Isolation and identification of the strains. The potential probiotic characterization involved gastric juice and bile resistance, antibiotic and antimicrobial activity, hydrophobicity, autoaggregation, coaggregation and adhesion assay in HT-29 cells. Organoleptic, viability and stability of probiotic strain in frozen cocoa pulp were evaluated.

RESULTS

Fourteen strains of Lactobacillus plantarum (9), Weissella paramesenteroides (3), Lactobacillus fermentum (1), and Leuconostoc mesenteroides (1) were obtained. Most of the strains were resistant to simulated gastric acidity and bile salts. Almost all strains were sensitive to the antibiotics tested, except to ciprofloxacin and vancomycin. About 47% of the strains are potential producers of bacteriocins. High hydrophobicity was observed for four strains. Autoaggregation ranged from 8.3-72.6% and the coaggregation capacity from 5.2-60.2%. All of the assessed strains presented more than 90% of adhesion to HT-29 intestinal cells. The percentage of Salmonella inhibition in HT-29 cells ranged from 4.7-31.1%. No changes in color, aroma, and pH were observed in cocoa pulps after storage at -20 °C for 90 days.

CONCLUSION

Wild strains of acid lactic bacteria from cheese proved to be viable and stable in frozen Brazilian cocoa pulp. This work showed a promising application of L. plantarum isolated strains to be used with frozen cocoa pulp matrix in probiotics food industry.

Evaluation of probiotic Bacillus coagulans MTCC 5856 viability after tea and coffee brewing and its growth in GIT hostile environment

In recent years, probiotic functional foods have gained quite a popularity and become a preferred choice among consumers, due to their positive effects on the gut microbiota and overall health. However, it is imperative for a probiotic strain to remain live and active at the time of consumption in high enough population density, in order to provide such health benefits. Thus, this study aimed to investigate the Bacillus coagulans MTCC 5856 spore stability after tea and coffee brewing and its subsequent growth in gastrointestinal tract (GIT) hostile environment. B. coagulans MTCC 5856 showed remarkable survival (94.94% and 99.76% in unroasted green coffee and tea, respectively) after brewing conditions and was able to grow in GIT hostile conditions using tea and coffee as a sole nutritional source. B. coagulans MTCC 5856 inclusion in tea and coffee after brewing did not significantly (P > .05) alter the sensory profile when compared to that without the probiotic inclusion. Moreover, B. coagulans MTCC 5856 growth was significantly (P < .05) higher when water soluble fibers were added during brewing, suggesting a synergistic property. It showed over 99% viability (P > .05) in tea and coffee powder at room temperature up to 24 months of storage. This study demonstrated the stability of the tested probiotic strain B. coagulans MTCC 5856 after tea and coffee brewing and its growth in GIT hostile environment, thereby suggesting functional probiotic use in tea and coffee.