Immobilization technologies in probiotic food production

The Potential of Lactic Acid Bacteria and Dairy By-Products in Controlling Campylobacter jejuni in Poultry

Campylobacter jejuni (C. jejuni) is the primary Campylobacter species and a major cause of foodborne illness associated with poultry products. This review focuses on lactic acid bacteria (LAB), especially Lactobacillus species, and acid whey as a dairy by-product for C. jejuni control in poultry as a sustainable method. LAB strains L. crispatus exhibit a cecal colonization reduction of >90% by competitive exclusion and bacteriocin activity, while L. johnsonii FI9785 decrease bacterial load 4-5 log10. Acid whey, which is abundant in organic acids (e.g., lactic acid) and bioactive peptides (e.g., lactoferrin), reduces C. jejuni viability, decreasing the food product contamination on the carcass for a short time by 40%. LAB antimicrobial function becomes more effective when used with acid whey, although specific farm-related variables require additional optimization. Some of the key strategies include co-encapsulating LAB with acid whey or plant-derived antimicrobials for improving survival, conducting in vivo trials in commercial farm conditions to evaluate scalability, and adding whey into feed (1-2% inclusion) or applying it as a pre-slaughter spray. These strategies enable the antibiotic-free production and circular economy goals through repurposing low-cost acid whey. Future studies should directly compare them with standard antimicrobials to confirm their scalability for poultry safety.

Can polymeric nanofibers effectively preserve and deliver live therapeutic bacteria?

Probiotics and live therapeutic bacteria (LTB), their strictly regulated therapeutic counterpart, are increasingly important in treating and preventing biofilm-related diseases. This necessitates new approaches to (i) preserve bacterial viability during manufacturing and storage and (ii) incorporate LTB into delivery systems for enhanced therapeutic efficacy. This review explores advances in probiotic and LTB product development, focusing on preservation, protection, and improved delivery. Preservation of bacteria can be achieved by drying methods that decelerate metabolism. These methods introduce stresses affecting viability which can be mitigated with suitable excipients like polymeric or low molecular weight stabilizers. The review emphasizes the incorporation of LTB into polymer-based nanofibers via electrospinning, enabling simultaneous drying, encapsulation, and delivery system production. Optimization of bacterial survival during electrospinning and storage is discussed, as well as controlled LTB release achievable through formulation design using gel-forming, gastroprotective, mucoadhesive, and pH-responsive polymers. Evaluation of the presence of the actual therapeutic strains, bacterial viability and activity by CFU enumeration or alternative analytical techniques is presented as a key aspect of developing effective and safe formulations with LTB. This review offers insights into designing delivery systems, especially polymeric nanofibers, for preservation and delivery of LTB, guiding readers in developing innovative biotherapeutic delivery systems.

Spray drying of reconstituted skim milk fermented with Lactobacillus rhamnosus GG: control of glass transition and stickiness

The effects of glass transition and stickiness on the direct spray drying of reconstituted skim milk (RSM) fermented with Lactobacillus rhamnosus GG (LGG) were investigated. The fermented RSM did not spray dry properly due to severe wall depositions; however, it dried well (comparable to the control; RSM with resuspended LGG cells) when skim milk powder (SMP) was added. Adding SMP significantly increased the glass transition and sticky point temperatures of spray-dried powder, ranging from 18.2 to 72.4 °C and 34.5 to 78.5 °C, respectively, in a water activity range of 0-0.33. By adding SMP, droplets quickly shifted from a sticky plastic to a non-sticky glassy state during drying, resulting in reduced wall deposition. Although this spray-dried powder exhibited relatively high moisture sorption and lactose crystallization, the correlations between glass transition, stickiness, and moisture sorption suggested that its storage stability at 25 °C may be on par with the control powder.

Functional Modulation of Gut Microbiota and Blood Parameters in Diabetic Rats Following Dietary Intervention with Free or Immobilized Pediococcus acidilactici SK Cells on Pistachio Nuts

BACKGROUND/OBJECTIVES

The gut microbiota is linked to the pathogenesis of type 1 diabetes mellitus (T1DM), while supplementation with probiotics may result in positive alterations in the composition of the gut microbiome. This research aimed to map the changes in the gut microbiome and blood markers of streptozotocin-induced diabetic rats after a dietary intervention with free or immobilized cells of the presumptive probiotic Pediococcus acidilactici SK on pistachio nuts.

METHODS

Twenty-four male Wistar rats were studied and divided into four groups (healthy or diabetic) which received the free or the immobilized P. acidilactici SK cells on pistachio nuts for 4 weeks. Blood, fecal, and intestinal tissue samples were examined.

RESULTS

The diabetic rats exhibited an elevated concentration of HDL-c, while the inflammatory IL-1β levels were significantly lower in the diabetic animals that received the immobilized cells compared to the group that received the free cells. The dietary intervention with immobilized cells led to decreased counts of fecal staphylococci and enterococci in the diabetic animals, while the diet with both free and immobilized P. acidilactici SK cells rendered levels of these populations in normal values in the feces and intestinal tissue of the diabetic animals. Noticeably, the Lactobacillus and Bifidobacterium genera were elevated after the supplementation with immobilized P. acidilactici SK cells on pistachio nuts.

CONCLUSIONS

Dietary supplementation with P. acidilactici SK cells (in free or in immobilized form) beneficially affected the gut microbiota/microbiome of streptozotocin-induced diabetic rats, leading to the alleviation of dysbiosis and inflammation and control over their lipid levels.

Improvement of ɣ-Aminobutyric Acid Production and Cell Viability of Lactiplantibacillus plantarum B7 via Whole-Cell Immobilisation in Repeated Batch Fermentation System

Whole-cell immobilisation technology involving ℽ-aminobutyric acid GABA biosynthesis using lactic acid bacteria (LAB) has been extensively studied owing to its numerous benefits over free-living bacteria, including enhanced productivity, improved cell viability, ability to prevent cell lysis and protect cells against bacteriophages and other stressful conditions. Therefore, a novel LAB biocatalyst was developed using various fruit and fruit waste, immobilising a potential probiotic strain, Lactiplantibacillus plantarum B7, via an adsorption method to improve GABA and cell viability. Apple and watermelon rind have been known to be the ideal natural supports for L. plantarum B7 owing to higher GABA and lactic acid production and improved cell viability among the other natural supports tested and selected to be used in repeated batch fermentation (RBF) to improve GABA production and cell viability. In general, immobilisation of L. plantarum B7 on natural support has better GABA and lactic acid production with improved cell viability via RBF compared to free cells. Watermelon rind-supported cells and apple-supported cells could produce nine and eight successful GABA cycles, respectively, within RBF, whereas free cells could only produce up to four cycles. When using watermelon rind-supported cells and apple-supported cells in RBF, the GABA titer may be raised by up to 6.7 (218.480 ± 0.280 g/L) and 6 (195.439 ± 0.042 g/L) times, respectively, in comparison to GABA synthesis by free cells in single batch fermentation (32.65 ± 0.029 g/L). Additionally, natural support immobilised L. plantarum B7 could retain half of its cell viability even after the 12th cycle of RBF, while no cell was observed in control.

Effects of Free or Immobilized Pediococcus acidilactici ORE5 on Corinthian Currants on Gut Microbiome of Streptozotocin-Induced Diabetic Rats

The present study aimed to investigate the effect of a dietary intervention including free or immobilized cells of the presumptive probiotic Pediococcus acidilactici ORE5 on Corinthian currants, a food with beneficial impact in the condition of Type-1 Diabetes Mellitus (T1DM), on the microbiome composition of STZ-induced diabetic rats. Twenty four male Wistar rats were divided into four groups (n = 6 per group): healthy animals, which received the free (H_FP) or the immobilized Pediococcus acidilactici ORE5 cells (H_IPC), and diabetic animals, which received the free (D_FP) or the immobilized Pediococcus acidilactici ORE5 cells(D_IPC) for 4 weeks (109 cfu/day, in all groups). At the end of the dietary intervention, the D_IPC group exerted a lower concentration of the inflammatory cytokine IL-1 beta compared to D_FP. Consumption of immobilized P. acidilactici ORE5 cells on Corinthian currants by diabetic animals led to increased loads of fecal lactobacilli and lower Enterobacteriaceae, coliforms, and Escherichia coli levels, while Actinobacteria phylum, Akkermansia, and Bifidobacterium genera abundances were increased, and fecal lactic acid was elevated. Overall, the results of the present research demonstrated that functional ingredients could ameliorate gut dysbiosis present in T1DM and could be used to design dietary patterns aiming at T1DM management. However, well-designed clinical trials are necessary, in order to confirm the beneficial effects in humans.

Encapsulated probiotic Lactiplantibacillus strains with promising applications as feed additives for broiler chickens

Lactic acid bacteria (LAB), particularly Lactobacilli strains, represent a widely studied and promising group of probiotics with numerous potential health benefits. In this study, we isolated LAB strains from fecal samples of healthy broiler chickens and characterized their probiotic properties. Out of 62 initial isolates, five strains were selected for further investigations based on their antibacterial activity against pathogenic bacteria. These selected strains were identified as Lactiplantibacillus species. They exhibited desirable probiotic traits, including non-hemolyis, non-cytotoxicity, lack of antibiotic resistance, acid tolerance, auto-aggregation, and antioxidative potential. Encapsulation of these strains in alginate beads enhanced their survival compared to free cells, in stomach (69-87 % vs. 34-47 %) and intestinal (72-100 % vs. 27-51 %) juices, after 120 min exposure. These findings suggest that encapsulated Lactiplantibacillus strains could be used as feed additives for broiler chickens. Nevertheless, further studies are needed to set on their probiotic potential in vivo.

Mechanisms of medicinal, pharmaceutical, and immunomodulatory action of probiotics bacteria and their secondary metabolites against disease management: an overview

Probiotics or bacteriotherapy is today's hot issue for public entities (Food and Agriculture Organization, and World Health Organization) as well as health and food industries since Metchnikoff and his colleagues hypothesized the correlation between probiotic consumption and human's health. They contribute to the newest and highly efficient arena of promising biotherapeutics. These are usually attractive in biomedical applications such as gut-related diseases like irritable bowel disease, diarrhea, gastrointestinal disorders, fungal infections, various allergies, parasitic and bacterial infections, viral diseases, and intestinal inflammation, and are also worth immunomodulation. The useful impact of probiotics is not limited to gut-related diseases alone. Still, these have proven benefits in various acute and chronic infectious diseases, like cancer, human immunodeficiency virus (HIV) diseases, and high serum cholesterol. Recently, different researchers have paid special attention to investigating biomedical applications of probiotics, but consolidated data regarding bacteriotherapy with a detailed mechanistically applied approach is scarce and controversial. The present article reviews the bio-interface of probiotic strains, mainly (i) why the demand for probiotics?, (ii) the current status of probiotics, (iii) an alternative to antibiotics, (iv) the potential applications towards disease management, (v) probiotics and industrialization, and (vi) futuristic approach.

Development of a functional Greek sheep yogurt incorporating a probiotic Lacticaseibacillus rhamnosus wild-type strain as adjunct starter culture

Greek yogurt is a fermented dairy product of high nutritional value that can be used as a matrix for the delivery of probiotics. The aim of this study was to develop a new probiotic Greek sheep yogurt with upgraded quality and functional characteristics. To do this, yogurt was manufactured by fermenting pasteurized milk with the commercial starter culture (Streptococcus thermophilus (ST), Lactobacillus bulgaricus (LB)) together with a probiotic Lacticaseibacillus rhamnosus (LR) wild-type strain (probiotic yogurt; PY). As a control, yogurt manufactured with only the starter culture (ST, LB) was used (conventional yogurt; CY) The survival of all three lactic acid bacteria (LAB) species (ST, LB, and LR) was monitored throughout the products' shelf life (storage at 4 °C for 25 days), and also following exposure to a static in vitro digestion model (SIVDM). The population dynamics of total aerobic plate count (APC), Enterobacteriaceae, yeasts and molds grown in both yogurts were also determined. The total antioxidant activity (AA) of yogurts was comparatively determined using in parallel two different assays, whereas the Folin-Ciocalteu assay was used to determine their total phenolic content (TPC). At each sampling day, yogurts were also evaluated for their pH, titratable acidity (TA) and main sensory characteristics. The population of probiotic LR remained stable during the shelf life (and above 108 CFU/g). Yogurt starters (ST, LB) were not detected following SIVDM, whereas LR (in PY) presented a reduction of about only one log. The AA and TPC of PY were found significantly higher than that of CY (P < 0.05). At the end of storage (25th day), neither pH nor TA differed significantly between the two yogurt types, while no fungal growth was observed in the PY. Consumer sensory analysis did not reveal important differences between the two yogurt types during their shelf life. To sum up, the novel yogurt was able to deliver to consumers a high number of probiotic cells (>108 CFU/g), presented increased antioxidant power, had an expanded shelf life, and maintained its good sensory attributes.

Prebiotic Cellulose-Pullulan Matrix as a "Vehicle" for Probiotic Biofilm Delivery to the Host Large Intestine

This study describes the development of a new combined polysaccharide-matrix-based technology for the immobilization of Lactobacillus rhamnosus GG (LGG) bacteria in biofilm form. The new composition allows for delivering the bacteria to the digestive tract in a manner that improves their robustness compared with planktonic cells and released biofilm cells. Granules consisting of a polysaccharide matrix with probiotic biofilms (PMPB) with high cell density (>9 log CFU/g) were obtained by immobilization in the optimized nutrient medium. Successful probiotic loading was confirmed by fluorescence microscopy and scanning electron microscopy. The developed prebiotic polysaccharide matrix significantly enhanced LGG viability under acidic (pH 2.0) and bile salt (0.3%) stress conditions. Enzymatic extract of feces, mimicking colon fluid in terms of cellulase activity, was used to evaluate the intestinal release of probiotics. PMPB granules showed the ability to gradually release a large number of viable LGG cells in the model colon fluid. In vivo, the oral administration of PMPB granules in rats resulted in the successful release of probiotics in the colon environment. The biofilm-forming incubation method of immobilization on a complex polysaccharide matrix tested in this study has shown high efficacy and promising potential for the development of innovative biotechnologies.

About Functional Foods: The Probiotics and Prebiotics State of Art

Poor diet, obesity and a sedentary lifestyle have a significant impact on natural microbiota disorders; specifically, the intestinal one. This in turn can lead to a multitude of organ dysfunctions. The gut microbiota contains more than 500 species of bacteria and constitutes 95% of the total number of cells in the human body, thus contributing significantly to the host's resistance to infectious diseases. Nowadays, consumers have turned to purchased foods, especially those containing probiotic bacteria or prebiotics, that constitute some of the functional food market, which is constantly expanding. Indeed, there are many products available that incorporate probiotics, such as yogurt, cheese, juices, jams, cookies, salami sausages, mayonnaise, nutritional supplements, etc. The probiotics are microorganisms that, when taken in sufficient amounts, contribute positively to the health of the host and are the focus of interest for both scientific studies and commercial companies. Thus, in the last decade, the introduction of DNA sequencing technologies with subsequent bioinformatics processing contributes to the in-depth characterization of the vast biodiversity of the gut microbiota, their composition, their connection with the physiological function-known as homeostasis-of the human organism, and their involvement in several diseases. Therefore, in this study, we highlighted the extensive investigation of current scientific research for the association of those types of functional foods containing probiotics and prebiotics in the diet and the composition of the intestinal microbiota. As a result, this study can form the foundation for a new research path based on reliable data from the literature, acting a guide in the continuous effort to monitor the rapid developments in this field.

Novel Functional Grape Juices Fortified with Free or Immobilized Lacticaseibacillus rhamnosus OLXAL-1

During the last decade, a rising interest in novel functional products containing probiotic microorganisms has been witnessed. As food processing and storage usually lead to a reduction of cell viability, freeze-dried cultures and immobilization are usually recommended in order to maintain adequate loads and deliver health benefits. In this study, freeze-dried (free and immobilized on apple pieces) Lacticaseibacillus rhamnosus OLXAL-1 cells were used to fortify grape juice. Juice storage at ambient temperature resulted in significantly higher (>7 log cfu/g) levels of immobilized L. rhamnosus cells compared to free cells after 4 days. On the other hand, refrigerated storage resulted in cell loads > 7 log cfu/g for both free and immobilized cells for up to 10 days, achieving populations > 109 cfu per share, with no spoilage noticed. The possible resistance of the novel fortified juice products to microbial spoilage (after deliberate spiking with Saccharomyces cerevisiae or Aspergillus niger) was also investigated. Significant growth limitation of both food-spoilage microorganisms was observed (both at 20 and 4 °C) when immobilized cells were contained compared to the unfortified juice. Keynote volatile compounds derived from the juice and the immobilization carrier were detected in all products by HS-SPME GC/MS analysis. PCA revealed that both the nature of the freeze-dried cells (free or immobilized), as well as storage temperature affected significantly the content of minor volatiles detected and resulted in significant differences in the total volatile concentration. Juices with freeze-dried immobilized cells were distinguished by the tasters and perceived as highly novel. Notably, all fortified juice products were accepted during the preliminary sensory evaluation.

Development of engineered probiotics with tailored functional properties and their application in food science

The potential health benefits of probiotics may not be cognized because of the substantial curtailment in their viability during food storage and passage through the gastrointestinal system. Intestinal flora composition, and resistance against pathogens are among the health benefits associated with probiotic consumption. In the gastric environment, pH 2.0, probiotics dramatically lose their viability during the transit through the gastrointestinal system. The challenge remains to maintain cell viability until it reaches the large intestine. In extreme conditions, such as a decrease in pH or an increase in temperature, encapsulation technology can enhance the viability of probiotics. Probiotic bacterial strains can be encapsulated in a variety of ways. The methods are broadly systematized into two categories, liquid and solid delivery systems. This review emphasizes the technology used in the research and commercial sectors to encapsulate probiotic cells while keeping them alive and the food matrix used to deliver these cells to consumers.

Graphical abstract

Immobilization of Lactobacillus plantarum NCIMB 8826 ameliorates Citrobacter rodentium induced lesions and enhances the gut inflammatory response in C57BL/6 weanling mice

Infectious diarrhea is a major cause of infant mortality in most developing countries. In this research, we evaluated the potential of immobilized Lactobacillus plantarum NCIMB 8826 on weanimix infant cereal and its effectiveness in reducing the severity of Citrobacter rodentium-induced diarrhea in weanling mice. Thirty-six C57BL/6 weanling mice were placed into four groups (n = 9 each; negative, positive, prevention and cure). Mice received either L. plantarum (109 CFU/g) immobilized on weanimix infant cereal 3 days before C. rodentium (109 CFU/ ml) infection (Prevention) or 3 days after C. rodentium infection (Cure). A positive control group was infected with C. rodentium only, while a negative control group received neither L. plantarum nor C. rodentium. Positive control mice showed colonic mucosal and submucosal inflammation, erosion, and mucosal epithelia hyperplasia with the C. rodentium infection. Mice in the prevention and cure groups had less severe histologic alterations in the colon. Some beneficial effect of L. plantarum was observed in cecal short-chain fatty acid concentrations, which stimulates water and electrolytes absorption to reduce diarrhea. Our findings demonstrated that L. plantarum NCIMB 8826 could be immobilized on weanimix infant cereal to help reduce diarrhea during weaning.

Graphical Abstract

Lacticaseibacillus paracasei KC39 Immobilized on Prebiotic Wheat Bran to Manufacture Functional Soft White Cheese

In the current study, probiotic Lacticaseibacillus paracasei KC39 was immobilized on wheat bran as a carrier. The immobilized synbiotic biocatalyst was freeze-dried and used as an adjunct during the production of functional soft white cheese. Free freeze-dried Lc. paracasei cells as an adjunct and a control cheese with a commercial starter were used for comparison. In addition to a fiber content of 1.12%, the functional cheese made using the synbiotic biocatalyst showed higher cell viabilities in the gastric and intestinal phases as well as an enhanced microstructure and favorable sensory characteristics. The presented immobilization method could be applied to the production of soft cheese and other functional food products for the stabilized delivery of both probiotics and dietary fibers.

Screening of Antibacterial Efficacy of Chitosan Encapsulated Probiotics (Lactococcus lactis and Lactobacillus curvattus) against Clinical Bacterial Pathogens

Probiotics frontier in depressing the clinical bacterial pathogens to avoid multidrug resistance phenomenon. The present study aimed to determine the antibacterial efficiency of chitosan encapsulated probiotics isolated from buffalo milk samples against clinical bacterial pathogens. The Agar well method was used for antibacterial activity. Lactococcus lactis (A) and Lactobacillus curvattus (B) were isolated from fresh buffalo milk samples, identified via culturing media, Gram's staining, biochemical tests, and antibiogram analysis. Encapsulation of probiotics was carried out using chitosan and was characterized via a scanning electron microscope. Antibiogram analysis elicit that L. lactis culture (A1) was highly sensitive to chloramphenicol (17.66±0.47 mm), tobramycin (15.33±0.47 mm), and ciprofloxacin (12.33±0.47 mm) and resistant against tetracycline, Penicillin G, Erythromycin, Amoxycillin, Ceftriaxone, Cephalothin, and Cephradine, while L. curvattus culture (B1) was affected by Ceftriaxone (18.67±0.47 mm), Amoxycillin (14.33±0.94 mm), Cephalothin (13.67±0.47 mm), Erythromycin (13.33±0.47 mm), Penicillin G (12.67±0.47 mm), Cephradine (10.33±0.47 mm), and Chloramphenicol (9.67±0.47 mm) and resistant against tetracycline, Tobramycin, and Ciprofloxacin. Antibacterial efficacy of non-encapsulated probiotic cultures was significant and maximum inhibition of bacterial were recorded compared to their cellular components. SEM of encapsulated probiotics revealed that they were successfully covered with a chitosan protective layer and could be effective as bio-preservatives due to being slowly released at the target site. The current study concluded that L. lactis, L. curvattus, and their cellular components have a significant bactericidal effect against infectious pathogens and could be used as a potential therapeutic drug against infectious diseases.

A novel technique for the preparation of curd (Dahi) by PVDF membrane-based strip

Preparation of curd at home is quite challenging as it requires skills like addition of proper amount of starter culture, maintenance and storage of inoculum for the preparation of good and consistent quality curd. The present work utilized bacterial attachment property of PVDF (Polyvinylidene fluoride) membrane to prepare a strip which can be dipped into milk for the preparation of consistent quality curd. Shelf-life of the strip is around 100 days. The strip prepared curd was well comparable with the curd prepared by the commercial inoculum based on their pH, % lactic acid, % syneresis and bacterial load. Strip of size 5 × 5 cm2 was enough for preparation of 500 mL curd. It was proved by different analytical techniques like AFM, SEM and FTIR that PVDF was not having any leaching property during curd preparation. It can also be used in repeated contact with food products, as it is FDA (Food and Drug Administration) compliant and non-toxic. The curd strip has significant industrial relevance as it is a cost-effective alternative of any commercial inoculum (very expensive) and also meets the demand of consumers with the rising health awareness and busy lifestyles. Further, it is spillage proof, portable, ready-to-use.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-021-05339-3.

Berry By-Products in Combination with Antimicrobial Lactic Acid Bacteria Strains for the Sustainable Formulation of Chewing Candies

The purpose of this research was to develop formulations of chewing candies (CCs) in a sustainable manner by using berry by-products in combination with antimicrobial lactic acid bacteria (LAB) strains. To implement this aim, the optimal quantities of by-products from lyophilised raspberry (Rasp) and blackcurrant (Bcur) from the juice production industry were selected. Prior to use, Lactiplantibacillus plantarum LUHS135, Liquorilactobacillusuvarum LUHS245, Lacticaseibacillusparacasei LUHS244, and Pediococcus acidilactici LUHS29 strains were multiplied in a dairy industry by-product-milk permeate (MP). The antimicrobial activity of the selected ingredients (berry by-products and LAB) was evaluated. Two texture-forming agents were tested for the CC formulations: gelatin (Gl) and agar (Ag). In addition, sugar was replaced with xylitol. The most appropriate formulation of the developed CCs according to the product's texture, colour, total phenolic compound (TPC) content, antioxidant activity, viable LAB count during storage, overall acceptability (OA), and emotions (EMs) induced in consumers was selected. It was established that the tested LAB inhibited three pathogens out of the 11 tested, while the blackcurrant by-products inhibited all 11 tested pathogens. The highest OA was shown for the CC prepared with gelatin in addition to 5 g of Rasp and 5 g of Bcur by-products. The Rasp and LUHS135 formulation showed the highest TPC content (147.16 mg 100 g^-1 d.m.), antioxidant activity (88.2%), and LAB count after 24 days of storage (6.79 log₁₀ CFU g^-1). Finally, it was concluded that Gl, Rasp and Bcur by-products, and L. plantarum LUHS135 multiplied in MP are promising ingredients for preparing CCs in a sustainable manner; the best CC formula consisted of Gl, Rasp by-products, and LUHS135 and showed the highest OA (score 9.52) and induced the highest intensity of the EM 'happy' (0.231).

Encapsulation of probiotics: past, present and future

Background

Probiotics are live microbial supplements known for its health benefits. Consumption of probiotics reported to improve several health benefits including intestinal flora composition, resistance against pathogens. In the recent years, there is an increasing trend of probiotic-based food products in the market.

Main body

Probiotics cells are targeted to reach the large intestine, and the probiotics must survive through the acidic conditions of the gastric environment. It is recommended to formulate the probiotic bacteria in the range of 108–109 cfu/g for consumption and maintain the therapeutic efficacy of 106–107 cfu/g in the large intestine. During the gastrointestinal transit, the probiotics will drastically lose its viability in the gastric environment (pH 2). Maintaining cell viability until it reaches the large intestine remains challenging task. Encapsulating the probiotics cells with suitable wall material helps to sustain the survival of probiotics during industrial processing and in gastrointestinal transit. In the encapsulation process, cells are completely enclosed in the wall material, through different techniques including spray drying, freeze drying, extrusion, spray freeze drying, emulsification, etc. However, spray-drying and freeze-drying techniques are successfully used for the commercial formulation; thus, we limited to review those encapsulation techniques.

Short conclusions

The survival rate of spray-dried probiotics during simulated digestion mainly depends on the inlet air temperature, wall material and exposure in the GI condition. And fermentation, pH and freeze-drying time are the important process parameters for maintaining the viability of bacterial cells in the gastric condition. Improving the viability of probiotic cells during industrial processing and extending the cell viability during storage and digestion will be the main concern for successful commercialization.

Graphical abstract

Evaluation of inhibitory and probiotic properties of lactic acid bacteria isolated from vaginal microflora

Lactic acid bacteria (LABs) are known to secrete species-specific secondary metabolites that could be utilized as novel therapeutics against multi-drug resistant pathogens. This study aimed to investigate the antagonistic and probiotic properties of LABs isolated from the vaginal ecosystem of healthy women and to assess the stability of their antagonistic metabolites. Among 43 strains isolated from healthy women, eight LAB strains exhibited detectable BLISs (bacteriocin-like substances) producing ability against E. faecalis (JH-86), S. aureus (JH-68), Streptococcus sp. (JH-80), and E. coli (JH-101), with zone of inhibition (ZI) ranging from 9.00 to 20.33 mm and minimum inhibitory concentrations (MICs) from 62.5 to 500 μL/mL, respectively. The partially purified compounds extracted from cell free supernatant (CFS) displayed an increase in antagonistic activity based on ZI, 9.67-30.17 mm and MICs, 3.91-15.63 mg/mL, respectively. In a time-kill study, both crude and partially purified compounds of Limosilactobacillus reuteri (MT180537), Pediococcus pentosaceus (MT176555), Limosilactobacillus pontis (MW362838), and Levilactobacillus brevis (MW362790) exhibited significant bactericidal action against E. faecalis (MW051601), the most frequent etiological agent of aerobic vaginitis (AV). The active secondary metabolites from L. reuteri (MT180537), P. pentosaceus (MT176555), and L. pontis (MW362838) were protein in nature and remained stable under different physicochemical conditions. Regarding probiotic properties, the strains presented probiotic characteristics, i.e., good acid, bile salt tolerance, aggregation properties, and biofilm formation. The strains were susceptible to most of the commonly used antibiotics and had no hemolytic activity. In conclusion, antagonistic compounds or BLIS produced by L. reuteri (MT180537) could be investigated further for preparation of ointments to treat AV.

Advancements in the Use of Fermented Fruit Juices by Lactic Acid Bacteria as Functional Foods: Prospects and Challenges of Lactiplantibacillus (Lpb.) plantarum subsp. plantarum Application

Lactic acid fermentation of fresh fruit juices is a low-cost and sustainable process, that aims to preserve and even enhance the organoleptic and nutritional features of the raw matrices and extend their shelf life. Selected Lactic Acid Bacteria (LAB) were evaluated in the fermentation of various fruit juices, leading in some cases to fruit beverages, with enhanced nutritional and sensorial characteristics. Among LAB, Lactiplantibacillus (Lpb.) plantarum subsp. plantarum strains are quite interesting, regarding their application in the fermentation of a broad range of plant-derived substrates, such as vegetables and fruit juices, since they have genome plasticity and high versatility and flexibility. L. plantarum exhibits a remarkable portfolio of enzymes that make it very important and multi-functional in fruit juice fermentations. Therefore, L. plantarum has the potential for the production of various bioactive compounds, which enhance the nutritional value and the shelf life of the final product. In addition, L. plantarum can positively modify the flavor of fruit juices, leading to higher content of desirable volatile compounds. All these features are sought in the frame of this review, aiming at the potential and challenges of L. plantarum applications in the fermentation of fruit juices.

Co-Encapsulated Synbiotics and Immobilized Probiotics in Human Health and Gut Microbiota Modulation

Growing interest in the development of innovative functional products as ideal carriers for synbiotics, e.g., nutrient bars, yogurt, chocolate, juice, ice cream, and cheese, to ensure the daily intake of probiotics and prebiotics, which are needed to maintain a healthy gut microbiota and overall well-being, is undeniable and inevitable. This review focuses on the modern approaches that are currently being developed to modulate the gut microbiota, with an emphasis on the health benefits mediated by co-encapsulated synbiotics and immobilized probiotics. The impact of processing, storage, and simulated gastrointestinal conditions on the viability and bioactivity of probiotics together with prebiotics such as omega-3 polyunsaturated fatty acids, phytochemicals, and dietary fibers using various delivery systems are considered. Despite the proven biological properties of synbiotics, research in this area needs to be focused on the proper selection of probiotic strains, their prebiotic counterparts, and delivery systems to avoid suppression of their synergistic or complementary effect on human health. Future directions should lead to the development of functional food products containing stable synbiotics tailored for different age groups or specifically designed to fulfill the needs of adjuvant therapy.

Perspective on Constructing Cellulose-Hydrogel-Based Gut-Like Bioreactors for Growth and Delivery of Multiple-Strain Probiotic Bacteria

The current perspective presents an outlook on developing gut-like bioreactors with immobilized probiotic bacteria using cellulose hydrogels. The innovative concept of using hydrogels to simulate the human gut environment by generating and maintaining pH and oxygen gradients in the gut-like bioreactors is discussed. Fundamentally, this approach presents novel methods of production as well as delivery of multiple strains of probiotics using bioreactors. The relevant existing synthesis methods of cellulose hydrogels are discussed for producing porous hydrogels. Harvesting methods of multiple strains are discussed in the context of encapsulation of probiotic bacteria immobilized on cellulose hydrogels. Furthermore, we also discuss recent advances in using cellulose hydrogels for encapsulation of probiotic bacteria. This perspective also highlights the mechanism of probiotic protection by cellulose hydrogels. Such novel gut-like hydrogel bioreactors will have the potential to simulate the human gut ecosystem in the laboratory and stimulate new research on gut microbiota.

Role of probiotics in prevention and treatment of enteric infections: a comprehensive review

Microorganisms that inhabits human digestive tract affect global health and enteric disorders. Previous studies have documented the effectiveness and mode of action of probiotics and classified as human-friendly biota and a competitor to enteric pathogens. Statistical studies reported more than 1.5 billion cases of gastrointestinal infections caused by enteric pathogens and their long-term exposure can lead to mental retardation, temporary or permanent physical weakness, and leaving the patient susceptible for opportunistic pathogens, which can cause fatality. We reviewed previous literature providing evidence about therapeutic approaches regarding probiotics to cure enteric infections efficiently by producing inhibitory substances, immune system modulation, improved barrier function. The therapeutic effects of probiotics have shown success against many foodborne pathogens and their therapeutic effectiveness has been exponentially increased using genetically engineered probiotics. The bioengineered probiotic strains are expected to provide a better and alternative approach than traditional antibiotic therapy against enteric pathogens, but the novelty of these strains also raise doubts about the possible untapped side effects, for which there is a need for further studies to eliminate the concerns relating to the use and safety of probiotics. Many such developments and optimization of the classical techniques will revolutionize the treatments for enteric infections.

Ale beer containing free and immobilized Lactobacillus brevis, a potential delivery system for probiotics

Abstract

Probiotics in ale beer may be attractive to health-conscious consumers. However, beer conditions may decrease probiotic viability. Powder produced from durian (Durio zibethinus) rind, a by-product that is currently unutilized, can be used for the immobilization of probiotics. MRS medium was incubated with Lactobacillus brevis and periodically sampled to obtain the growth curve. Ale beer with free L. brevis and cells immobilized in durian rind powder was produced and separately assessed during storage at 21 °C for 24 days. The physico-chemical parameters of both beers did not differ significantly. Durian rind powder conferred protection up to 12 days of storage with the immobilized cells in the beer having a significantly higher count than the free cells, which can be due to the acid detergent fiber content (19.67%). Free and immobilized cells remained viable with counts of 4.89 and 5.00 log CFU/mL of beer, respectively, at the end of the storage period. Both treatments had approximate counts of 5 log CFU/mL after 120 min in simulated gastric and intestinal fluids. The predominant bacterial species present at the end of storage were L. brevis and L. farciminis. This study suggests that ale beer could be a potential delivery system for free and immobilized probiotic bacteria. This is one of the few studies demonstrating the use of probiotic lactic acid bacteria in beer brewing.

Graphical abstract

Probiotic fermented oat dairy beverage: viability of Lactobacillus casei, fatty acid profile, phenolic compound content and acceptability

The combination of oats such as water-soluble oat extract (SOE) and probiotic microorganisms can add nutritional value to the food and benefits to the consumer's health. The SOE contains soluble fiber, whose major soluble fraction is composed of β-glucan contains soluble antioxidants such as ferulic acid, avenanthramides and other phenolic acids. The purpose of this study was to develop a fermented dairy beverage containing SOE, evaluating the viability of the probiotic culture, the fatty acid profile, phenolic compounds content and sensory characteristics during the storage. It was verified that Lactobacillus casei remained viable during the 21 days of storage (count above 7 Log CFU.mL^-1) and that the addition of SOE does not affect the viability of probiotic bacteria. The levels of bioactive compounds soluble in aqueous medium, increased between the beginning of the experiment and the end, being influenced by the addition of SOE. Seven fatty acids were found in all formulations with a prevalence of C16:0 followed by C18:1. The addition of SOE in the formulation contributes to a significant increase in linoleic acid (C18:2n6). The sensory evaluation of the fermented oat dairy beverage with L. casei (BAC) was positive: the product was highly appreciated by consumers, with acceptance rate of 84.4%. The combination of SOE, with L. casei in the production of novel probiotic fermented dairy beverage, was technologically feasible, improving the functional properties of the product and offering health benefits to the consumer. More studies should be made to evaluate the composition and functional properties of SOE.

Alginate- and Gelatin-Coated Apple Pieces as Carriers for Bifidobacterium animalis subsp. lactis DSM 10140

Fruit and vegetables are considered good natural supports for microorganisms; however, probiotics could cause negative changes on some organoleptic and sensory traits. Thus, the main topic of this paper was the design of coated apple chips as carriers for probiotics with a high level of sensory traits. The research was divided into two steps. First, four functional strains (Limosilactobacillus reuteri DSM 20016, Bifidobacterium animalis subsp. lactis DSM 10140, and Lactiplantibacillus plantarum c16 and c19) were immobilized on apple pieces through dipping of fruit chips in probiotic suspensions for different contact times (from 15 to 30 min) and stored at 4°C for 12 days. Periodically, the viable count was assessed. As a result of this step, a contact time of 15 min was chosen because it assured an optimal deposition of microorganisms. In the second step, apple pieces inoculated with B. animalis subsp. lactis DSM 10140 were coated with alginate and gelatin and stored at 4 and 8°C for 10 days; pH, microbiological counts, color (browning index), and sensory scores were evaluated. Bifidobacterium animalis DSM 10140 exerted a negative effect on apple chips and cause a significant browning; however, the use of coating counteracted this phenomenon. In fact, coated chips showed higher sensory scores and lower browning index. In addition, gelatin showed better performances in terms of probiotic viability, because at 8°C, a significant viability loss of B. animalis DSM 10140 (1.2 log cfu/g) was found on alginate-coated chips. Gelatin-coated apple pieces with B. animalis subsp. lactis DSM 10140 could be an attractive functional food for a wide audience, although further investigations are required on in vivo effects of this product after consumption.

Physicochemical properties of soy protein hydrolysate and its formulation and stability with encapsulated probiotic under in vitro gastrointestinal environment

The objective of this study was to prepare protein isolate from defatted soybean and identify an optimal hydrolysis protocol to create improved hydrolysates and ascertain the optimum encapsulation technique for probiotics. Soy protein isolate (SPI) was prepared using an alkaline extraction procedure for solubility within a neutral, beverage-specific pH range. The soy protein hydrolysate (SPH) was prepared from aqueous extracted SPI using pepsin. The physicochemical properties of the SPH were investigated by solubility, degree of hydrolysis (DH), surface hydrophobicity, and electrophoresis. Hydrolysates from 2, 2.5, and 3 hr of hydrolysis time achieved the suitable DH between 2.5% to 5.0%. The 2.5 to 3 hr hydrolysates were also significantly more soluble than SPI at all pH levels from 85% to 95% solubility. Surface hydrophobicity of the hydrolysates ranged from 15 to 20 S0 values. Alginate (1%), resistant starch (2%), and probiotic culture (0.1%) were used as an encapsulation agent to protect probiotics. Alginate microcapsules were observed to be 1 mm in size using environmental scanning electron microscopy. The dried SPH and encapsulated probiotics with alginate in a dry powder formulation were tested for its gastrointestinal resistance and probiotic viability under in vitro simulated digestion. Approximately 1-log decrease was observed for all experimental groups after simulated digestion (final log colony forming units [CFU]/mL range: 6.55 to 6.19) with free probiotics having the lowest log CFU/mL (6.10 ± 0.10) value. No significant difference was observed among experimental groups for probiotic viability (P = 0.445). The findings of this research will provide an understanding of formulation for easily digestible protein and encapsulated probiotics. PRACTICAL APPLICATION: The findings of this research provide an understanding of improved formulation for more suitable soy protein hydrolysate and viability of encapsulated probiotics in gastrointestinal environment. Probiotics with the prebiotics in an encapsulated environment provide a technology for the enhancement of probiotics viability and for applications in suitable products for health and wellness.

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

The inoculation of probiotics in beverages (probiotication) requires special technologies, as probiotic microorganisms can experience stress during food processing (acid, cold, drying, starvation, oxidative, and osmotic stresses) and gastrointestinal transit. Survival to harsh conditions is an essential prerequisite for probiotic bacteria before reaching the target site where they can exert their health promoting effects, but several probiotics show a poor resistance to technological processes, limiting their use to a restricted number of food products. Therefore, this paper offers a short overview of the ways to improve bacterial resistance: by inducing a phenotypic modification (adaptation) or by surrounding bacteria through a physical protection (microencapsulation). A second topic briefly addressed is genetic manipulation, while the last section addresses the control of metabolism by attenuation through physical treatments to design new kinds of food.

A new delivery system based on apple pomace-pectin gels to encourage the viability of antimicrobial strains

This work was aimed to investigate the concept of the valorization of apple processing by-products to produce a new preservation system based on apple pomace gels to encourage the viability of antimicrobial Lactobacillus strains. A high frequency (850 kHz) low power (1.3 W/cm²) ultrasound-stimulated cavitation was used for the structure modulating of gels under low-temperature (50 ℃) conditions. Medium esterified apple pectin was added to apple pomace to improve its texture properties and stability. The monitoring of the process of gelation was performed by using acoustic technique and method, based on the measurement of the distance (parameter h, mm) traveled by a free-falling module. The obtained data were then compared to gel texture measurements. The results suggest that low power ultrasound leads to a reduced jelly mass stickiness and increased gel hardness, compared to the thermally treated sample. The immobilization of probiotic cells in low pectin apple pomace gels did not sufficiently protect the microorganisms. The higher viability of immobilized Lactobacillus paracasei (54-77%) compared to L. plantarum (43-59%) was recorded after incubation at acidic conditions (pH 2.0). The most suitable system for preserving bacterial cells during storage can be the apple pomace-pectin gel containing up to 53% pectin as a stabilizer retaining 84% of viable cells after one-month storage at 4 ℃. The apple pomace-pectin hydrogels with gelation rate (dh/dt) of 0.03-0.05 mm/s can be used for the preservation of bacterial cells as a suitable functional ingredient for food.

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.

Effect of Sugar Content on Quality Characteristics and Shelf-Life of Probiotic Dry-Fermented Sausages Produced by Free or Immobilized Lactobacillus casei ATCC 393

The aim of the present study was to investigate the effect of sugar content (0, 0.30, and 0.60%) on quality attributes and shelf-life of dry-fermented sausages stored for 66 days containing free or immobilized Lactobacillus casei ATCC 393 on wheat. For comparison, dry-fermented sausages with no starter culture were also produced. Physicochemical characteristics ranged within the levels usually observed in fermented sausages, while a drastic decrease was recorded in numbers of enterobacteria, staphylococci, and pseudomonads during ripening in all cases. Noticeably, sugar addition and the probiotic culture resulted in significant increase of shelf-life, whereas levels of L. casei ATCC 393 after 66 days of ripening persisted above 6 log cfu/g. Sugar addition had a positive effect on sensory attributes; although all products were of high quality, the immobilized cells provided a distinctive characteristic aroma and a fine taste.

Probiotics and Their Potential Preventive and Therapeutic Role for Cancer, High Serum Cholesterol, and Allergic and HIV Diseases

The potential health benefits of probiotics have long been elucidated since Metchnikoff and his coworkers postulated the association of probiotic consumption on human's health and longevity. Since then, many scientific findings and research have further established the correlation of probiotic and gut-associated diseases such as irritable bowel disease and chronic and antibiotic-associated diarrhea. However, the beneficial impact of probiotic is not limited to the gut-associated diseases alone, but also in different acute and chronic infectious diseases. This is due to the fact that probiotics are able to modify the intestinal microbial ecosystem, enhance the gut barrier function, provide competitive adherence to the mucosa and epithelium, produce antimicrobial substances, and modulate the immune activity by enhancing the innate and adaptive immune response. Nevertheless, the current literature with respect to the association of probiotic and cancer, high serum cholesterol, and allergic and HIV diseases are still scarce and controversial. Therefore, in the present work, we reviewed the potential preventive and therapeutic role of probiotics for cancer, high serum cholesterol, and allergic and HIV diseases as well as providing its possible mechanism of actions.

Dark Chocolate: Opportunity for an Alliance between Medical Science and the Food Industry?

Dark chocolate (DC) was originally introduced in human nutrition as a medicinal product consumable in a liquid form. Century-long efforts of food industry transformed this hardly appealing product into a valuable modern culinary delight with clear predominance of confectionery brands of DC on the market. However, current epidemiological data as well as multiple experimental and clinical observations reveal that DC consumption may have a profound effect on cardiovascular, central nervous systems, hemostasis, and lipid metabolism. However, despite of growing body of modern scientific evidence revealing medicinal properties of cocoa-based products, DC remains more gourmet culinary item than medicinal food product. Even today there are no clear dietary recommendations on consumption of cocoa flavonoids (flavanols) for health purpose. Clinical trials with DC rarely include monitoring of plasma flavanol concentration in volunteers. Moreover, there is no standardized assay or any quantitative requirements for flavanol content in the commercial brands of DC. High flavanol content is often sacrificed during manufacturing for a better taste of DC due to bitterness of cocoa flavonoids. All these problems including subsequently arising ethical issues need to be addressed by joint efforts of food industry and medical science. Moreover, application of microencapsulation technology in DC manufacturing, as well as molecular selection of best flavanol producers may drastically change bioavailability of DC bioactive ingredients and DC production technology. Nevertheless, only strict causative approach, linking possible health effect of DC to its bioactive ingredients considered as nutraceuticals, may change the current landscape in nutritional research related to cocoa-based products and create a trustworthy path for their medicinal use.

Importance of the gastrointestinal life cycle of Bacillus for probiotic functionality

Bacillus spp. are widely used in animal production for their probiotic properties. In many animal species, feed supplementation with specific Bacillus strains can provide numerous benefits including improvement in digestibility, the gut microbiota and immune modulation, and growth performance. Bacilli are fed to animals as spores that can sustain the harsh feed processing and long storage. However, the spores are metabolically quiescent and it is widely accepted that probiotics should be in a metabolically active state to perform certain probiotic functions like secretion of antimicrobial compounds and enzymes, synthesis of short chain fatty acids, and competition for essential nutrients. These functions should become active in the host gastrointestinal tract (GIT) soon after digestion of spores in order to contribute to microbiota and host metabolism. Considering that bacterial spores are metabolically dormant and many health benefits are provided by vegetative cells, it is of particular interest to discuss the life cycle of Bacillus in animal GIT. This review aims to capture the main characteristics of spores and vegetative cells and to discuss the latest knowledge in the life cycle of beneficial Bacillus in various intestinal environments. Furthermore, we review how the life cycle may influence probiotic functions of Bacillus and their benefits for human and animal health.

Saccharomyces cerevisiae from Brazilian kefir-fermented milk: An in vitro evaluation of probiotic properties

The therapeutic use of probiotics for supporting the antibiotic action against gastrointestinal disorders is a current trend and emerging applications have gained popularity because of their support for various microbiological activities in digestive processes. Microorganisms isolated from kefir with great probiotic properties, in addition to high resistance to harsh environmental conditions, have been widely researched. Administration of probiotic yeasts offers a number of advantages, when compared to bacteria, because of particular characteristics as their larger cell size. In the present study, 28 strains of Saccharomyces cerevisiae were isolated, after in vitro digestion of kefir-fermented milk, and identified by molecular based approaches. A screening was performed to determine important quality requirements for probiotics including: antagonistic and antioxidant activities, β-galactosidase synthesis, autoaggregation, surface hydrophobicity and adhesion to epithelial cells. The results showed strains: with antagonistic activity against microbial pathogens such as Klebsiella pneumoniae, Pseudomonas aeruginosa, Staphylococcus aureus, Bacillus subtilis; able to produce β-galactosidase; with antioxidant activity levels higher than 90%; with hydrophobicity activity and autoaggregation ability (evaluated by adhesion test, where all the strains presented adhesion to mice ileal epithelial cells). These findings are relevant and the strains are recommended for further in vivo studies as well as for potential therapeutic applications.