A new synbiotic dairy food containing lactobionic acid and Lactobacillus casei

As well as its beneficial health properties, the incorporation of the prebiotic lactobionic acid (LBA) in fermented dairy products can provide a technological advantage due to its gelling capacities. This study aimed to develop a new functional dairy product containing LBA synthesised within the process itself by the bacterium Pseudomonas taetrolens. A probiotic Lactobacillus casei strain was introduced through a sequential fermentation system. After incubation, in the case of the most effective experimental procedure, a synbiotic fermented milk with 30 g/L of prebiotic LBA was obtained, together with an active L. casei population of 10⁹ cfu/mL and <1% lactose content.     

Adherence of probiotic bacteria to human colon epithelial cells and inhibitory effect against enteric pathogens – In vitro study

The aim of this study was to determine the anti‐adherence properties of three probiotic lactobacillus strains (Lb. rhamnosus 0900, Lb. rhamnosus 0908 and Lb. casei 0919), and their mixture against pathogens: Escherichia coli ATCC 10536, Salmonella enterica serovar Typhimurium ATCC 14028 and Candida albicans ATCC 10231 using Caco‐2 human colon adenocarcinoma cells. All strains of lactobacilli and the probiotic mixture to the greatest extent inhibited adherence of S. Typhimurium, up to 91%. Lb. rhamnosus 0900 inhibited E. coli by 75.9%, and Lb. casei 0919 decreased adherence of C. albicans by 49%. All pathogens activated the adherence of the mixture of probiotic bacteria.     

Effect of cryoprotectants,prebiotics and microencapsulation on survival of probiotic organisms in yoghurt and freeze-dried yoghurt

The survival of probiotic microorganisms including Lactobacillus acidophilus, Lactobacillus casei, Lactobacillus rhamnosus and Bifidobacterium spp. was evaluated in yoghurt and freeze-dried yoghurt after processing and storage. The effectiveness of microencapsulating probiotic organisms as well as adding cryoprotectants and prebiotics in improving their viability was also investigated. The viability of Bifidobacterium infantis 17930 and L. rhamnosus GG was reduced by 0.07 log, while that of L. casei 1520 and Bifidobacterium longum 1941 was reduced by 0.28 and 0.39 log, respectively. There was a 7% improvement in the viability of L. casei 1520 when cryoprotectant ‘Unipectine™ RS 150’ was added at 2.5% (w/v). The prebiotic ‘Raftilose^®P95’ when added at 1.5% w/v to yoghurt improved the viability of the combined selected probiotic organisms by 1.42 log during four weeks of storage at 4 °C. Microencapsulation with alginate improved viability of combined selected probiotic organisms by 0.31 log in freeze-dried yoghurt stored at 21 °C.     

Innovative production of multistrain synbiotic product using Thai-pigmented rice and rice bran oil

This study found that the isolated probiotics Lactobacillus paracasei KUKPS6201, L. acidophilus KUKPS6107, L. reuteri KUKPS6103, L. rhamnosus KUKPS6007, L. salivarius KUKPS6202, Bacillus coagulans KPSTF02 and Saccharomyces boulardii KUKPS6005 had high potential for probiotic properties. All strains had antibacterial activity and high antioxidant activity of 1.654 ± 0.017 mg Trolox mL⁻¹ probiotic extract. The selected strains could survive in a simulated gastrointestinal tract under anaerobic conditions and showed no haemolytic activity. Furthermore, the probiotic strains were strongly auto-aggregated and also showed co-aggregated ability with pathogenic bacteria. The probiotic microorganisms demonstrated high ability to adhere to Thai-pigmented rice grains. The results of analysis of these probiotics showed that Riceberry rice bran oil was an excellent prebiotic. A synbiotic product containing Thai-pigmented rice grains (cultivar Riceberry, Luem Pua and Black Jasmine) and rice bran oil was produced. After 8 weeks of storage, the viability of the probiotics in terms of multistrains was 7.36 ± 0.04 log CFU g^–1 (85.78% survival rate). Microbiological safety testing indicated that the amounts of contaminants were acceptable. This study provided the first scientific report on the feasibility of applying Thai-pigment rice, rice bran oil and mixed-culture probiotics as a novel functional synbiotic product.     

The involvement of ATPase activity in the acid tolerance of Lactobacillus rhamnosus strain GG

This study examined the survival and acid stress response of nine lactic acid bacteria (LAB) including Lactobacillus rhamnosus strain GG in commercially available yoghurt products (low pH environment) during the long‐term storage. Under the storage conditions investigated (52 weeks period at 5 °C), there was a loss of the viability of Lactobacillus acidophilus, Lactobacillus casei and Bifidobacterium sp. within 35 weeks. However, L. rhamnosus strain GG, one of starter strains in a commercially available yoghurt product, exhibited excellent survival throughout the whole storage period. Our results indicate that the viability of L. rhamnosus strain GG was increased by modulating the stress‐related factors as well as the activity of ATPase with exposure to the low pH conditions.     

Antimicrobial and antidiabetic potential of synbiotic fermented milk: A functional dairy product

The current study was based on evaluation of the therapeutic potential (antimicrobial and antidiabetic) of a synbiotic fermented milk product developed by optimising levels of the prebiotic ingredients (fructooligosaccharide and isomaltooligosaccharide). The maximum growth rate (0.27 ± 0.21a cfu/mL) of Lactobacillus acidophilus ATCC^® 4357? was observed with 2.345–2.445% of fructooligosaccharide and 2.53–2.62% of isomaltooligosaccharide. Significant antimicrobial potential of the synbiotic fermented milk was observed against Escherichia coli and Staphylococcus aureus due to the addition of prebiotics. Similarly, the final product also showed 62.9%, 71.5% and 57.0% reduction in blood glucose, urea and creatinine levels, respectively, of diabetic rabbits, when supplemented with 6% of the synbiotic fermented milk. A synbiotic fermented milk product with significant therapeutic potential could be developed using fructooligosaccharide and isomaltooligosaccharide as prebiotic ingredients.     

Production of functional probiotic, prebiotic, and synbiotic ice creams

In this work, 3 types of ice cream were produced: a probiotic ice cream produced by adding potentially probiotic microorganisms such as Lactobacillus casei and Lactobacillus rhamnosus; a prebiotic ice cream produced by adding inulin, a prebiotic substrate; and a synbiotic ice cream produced by adding probiotic microorganisms and inulin in combination. In addition to microbial counts, pH, acidity, and physical and functional properties of the ice creams were evaluated. The experimental ice creams preserved the probiotic bacteria and had counts of viable lactic acid bacteria after frozen storage that met the minimum required to achieve probiotic effects. Moreover, most of the ice creams showed good nutritional and sensory properties, with the best results obtained with Lb. casei and 2.5% inulin.     

AN IMMUNOLOGICAL STUDY OF SOME LACTOBACILLI WHICH CAUSE BEER SPOILAGE

Antisera have been prepared using Lactobacillus brevis, L. casei var. alactosus and L. casei var. rhamnosus. The interaction between these and the acid-soluble antigens of a range of Lactobacillus strains, most of which were isolated from beer, has been studied using a gel diffusion precipitin test; the fluorescent antibody staining technique was used to observe the reaction between whole cells and the antisera. Gel diffusion demonstrated the presence of specific, group and non-specific antibodies. Thus, each antiserum contained (i) a specific antibody towards the organism used to produce the antiserum and towards others in the same taxonomic unit and (ii) a non-specific antibody reacting with antigens from each of the strains of Lactobacillus and also with cells of Pediococcus cerevisiae and Saccharomyces cerevisiae. Additionally (iii) a serum prepared against L. casei var. rhamnosus contained a group antibody which reacted with an antigen present in Streptobacteria but not in Betabacteria, whilst an antiserum made using L. brevis contained group antibodies reacting with L. brevis and L. plantarum. Fluorescent antibody staining confirmed these distinctions and, using adsorbed sera, allowed the rapid identification of lactobacilli which cause beer spoilage.     

Identification of Lactobacillus spp. in probiotic products by real-time PCR and melting curve analysis

A rapid and reliable technique for identifying the strains of lactic acid bacteria (LAB) was developed in this study, and the 16S ribosomal RNA gene (16S rRNA gene) was used as the target. Several species-specific primer pairs were designed based on the variability of 16S rRNA sequence(s) for differentiating 5 strains of lactobacilli which were added into probiotic products in Taiwan. It was simple to identify Lactobacillus acidophilus and L. delbrueckii by species-specific primers, but it could not be used to distinguish L. casei, L. paracasei and L. rhamnosus. Another PCR approach was developed with hybridization probes which were designed according to the difference among the 16S rRNA genes of L. casei, L. paracasei and L. rhamnosus, and melting curve analysis of the hybridization probe was used to distinguish them. It was found that this approach could identify L. paracasei and L. rhamnosus correctly but not separate L. paracasei from L. casei, the result was due to both of them had the same 16S rRNA sequence. These results suggest that melting curve analysis of PCR approach in this study is a rapid, simple and accurate method in distinguishing the closely related strains of lactobacilli.     

Development of potentially synbiotic fresh-cut apple slices

The aim of this study was, to develop potentially synbiotic fresh-cut apple wedges by applying probiotic bacteria (Lactobacillus rhamnosus GG) and prebiotics in the form of oligofructose and inulin. An assessment of the quality, sensory, polyphenol and volatile attributes of synbiotic and probiotic samples was also undertaken. Fructan analysis showed that all prebiotics remained stable over the 14 days storage period and an intake of 100 g of apple supplies 2–3 g of prebiotics. All samples sets contained ca. 10⁸ cfu/g over the test period, which is sufficient for a probiotic effect, and is comparable to counts of probiotic bacteria in commercially available dairy products. Browning index, firmness, acidity and dry matter remained stable throughout the 14 days compared to the control while applying prebiotic coatings resulted in an increase in soluble solids. Sensory assessment indicated acceptable quality of probiotic and synbiotic apple wedges. HPLC analysis showed levels of decrease in polyphenolic compounds. No difference was found between O₂ and CO₂ headspace concentration and volatile production of synbiotic samples and samples only treated with probiotics.     

Survival and activity of 5 probiotic lactobacilli strains in 2 types of flavored fermented milk

The viability of 5 probiotic lactobacilli strains (Lactobacillus acidophilus LA-5, Lactobacillus casei L01, Lactobacillus casei LAFTI L26, Lactobacillus paracasei Lcp37, and Lactobacillus rhamnosus HN001) was assessed in 2 types of probiotic flavored drink based on fermented milk during 21 days of refrigerated storage (5°C). Also, changes in biochemical parameters (pH, titrable acidity, and redox potential) during fermentation as well as the sensory attributes of final product were determined. Among the probiotic strains, L. casei LAFTI L26 exhibited the highest retention of viability during refrigerated storage period, while L. acidophilus LA-5 showed the highest loss of viability during this period. The decline in cell count of probiotic bacteria in strawberry fermented milk was significantly greater compared to peach fermented milk. In an overall approach, peach fermented milk containing L. casei LAFTI L26 was selected as the optimal treatment in this study in both aspects of viability and sensory accpeptibility.     

Effects of a Lactobacillus casei synbiotic on serum lipoprotein, intestinal microflora, and organic acids in rats

The main aim of this study was to evaluate the effectiveness of 3 synbiotic diets: 1) containing Lactobacillus casei ASCC 292 and fructooligosaccharides (LF diet); 2) containing L. casei ASCC 292 and maltodextrin (LM diet); and 3) containing L. casei ASCC 292, fructooligosaccharide, and maltodextrin (LFM diet) to reduce serum cholesterol in male Wistar rats. The effect of the synbiotic diets on intestinal microflora, concentration of organic acids, and the possibility of translocation of lactobacilli were also investigated. The LFM diet lowered serum total cholesterol and triglyceride levels, whereas the LM diet increased serum high-density lipoprotein cholesterol level. However, synbiotic diets did not contribute to a change in low-density lipoprotein cholesterol level compared with the control diet. There was a decrease in the population of staphylococci, bacteroides, Escherichia coli, and total coliforms in most bowel regions with the LFM diet compared with the control (which did not contain any synbiotic). In general, the LFM diet contributed to a higher concentration of lactic acid that may have contributed to the decrease in the population of pathogenic microorganisms compared with the control. Fructooligosaccharide was the preferred substrate for production of acetic acid. Results from this study showed that the synbiotic diet that contained L. casei ASCC 292, fructooligosaccharide, and maltodextrin beneficially altered cholesterol levels and produced a healthier bowel microbial population without translocation of lactobacilli to other organs.     

High-intensity ultrasound processed acerola juice containing oligosaccharides and dextran promotes Lacticaseibacillus casei NRRL B-442 growth

In the present study, a prebiotic acerola juice containing gluco-oligosaccharides and dextran was produced and processed by high-intensity ultrasound (HIUS). After a simulated in vitro digestion, the gluco-oligosaccharides and dextran maintained 90% and 80% of their initial concentration in all prebiotic’s juices. At the same time, Vitamin C and phenolic compounds concentration increased significantly by 19% and 7% (P < 0.05). After the in vitro digestion, the prebiotic juice HIUS processed by 10 min showed the highest increase in gluco-oligosaccharides and bioactive compound concentrations. The HIUS processing imparted some dextran hydrolysis and improved its fermentability by Lacticaseibacillus casei. Gluco-oligosaccharides were extensively consumed as substrate in simulated intestinal conditions, promoting the L. casei NRRL B-442 growth and production of organic acids and short-chain organic acids. The prebiotic juice HIUS processed for 6 min showed the best responses regarding the metabolism of L. casei NRRL B-442. The results showed high-intensity ultrasound processed acerola juices containing gluco-oligosaccharides and dextran as a prebiotic food.     

In vitro comparison of probiotic properties of Lactobacillus casei Zhang, a potential new probiotic, with selected probiotic strains

Since 2004, our research group has isolated 240 Lactobacillus strains from Koumiss, a traditional fermented alcoholic beverage prepared from mare's milk in Inner Mongolia, Xinjiang of China and Mongolia. Among these Lactobacillus strains a novel strain with potential probiotic properties, Lactobacillus casei Zhang, was screened out and studied extensively for its probiotic properties, health-promoting effects and fermentation characteristics. In vitro tests indicated that L. casei Zhang had high tolerance to simulated gastric, intestine juices and bile salts, similar to commercial probiotic strains such as Lactobacillus acidophilus NCFM, Lactobacillus rhamnosus GG, L. casei Shirota and Bifidobacterium animalis Bb12. Higher acid-production activity and proteolytic activity was observed in the fermented milk inoculated with L. casei Zhang during the refrigerated storage than in the samples inoculated with the selected commercial probiotics. The yogurt samples fermented with L. casei Zhang exhibited similarer viable count (1.0 × 10⁹ cfu/mL) as the other samples after 28 d of refrigerated storage. The results suggested that L. casei Zhang showed good potential for application in functional foods and health-related products.     

Assessing the acid tolerance and the technological robustness of probiotic cultures for fortification in fruit juices

The suitability of probiotic cultures as fruit juice supplements was examined by assessing their acid tolerance and technological robustness. Survival of Lactobacillus and Bifidobacterium strains in orange juice (OJ), pineapple juice (PJ) and cranberry juice (CJ) was monitored. Results revealed that extensive differences exist among probiotic strains regarding their acid resistance. All of the strains screened survived for longer in OJ and PJ compared to CJ. L. casei DN-114 001, L. rhamnosus GG and L. paracasei NFBC43338 displayed the greatest robustness surviving at levels above 10⁷ cfu ml^− 1 in OJ and above 10⁶ cfu ml^− 1 in PJ for at least 12 weeks. Probiotic tolerance to thermal and non-thermal processing was studied to determine the feasibility of their addition to OJ prior to pasteurisation. OJ fortified with probiotic cultures was subjected thermal pasteurisation at 76 °C for 30 s and 90 °C for 1 min in addition to a high pressure treatment of 400 MPa for 5 min. Results indicated no strain was capable of withstanding treatments necessary to achieve a stable juice at levels > 10⁶ cfu ml^− 1. The outcome of the overall study points to L. rhamnosus GG, L. casei DN-114 001 and L. paracasei NFBC43338 as having promising potential for exploitation as functional supplements in fruit juices due to their impressive tolerance in acidic environments; however, fortification post processing is recommended.Industrial relevanceThe ability of health-promoting cultures to survive for at least 12 weeks in orange juice and pineapple juice at commercially critical levels renders them suitable strains for exploitation. Their inclusion may enhance the market potential of these already successful beverages.     

Yacon (Smallanthus sonchifolius) and Lactobacillus acidophilus CRL 1014 reduce the early phases of colon carcinogenesis in male Wistar rats

The modifying effects of aqueous yacon extract (AYE) and Lactobacillus acidophilus CRL 1014 against colon carcinogenesis induced by 1,2-dimethylhydrazine (DMH) in male Wistar rats were investigated. Animals were allocated into five groups: G1: untreated group; G2: DMH-treated group; G3: DMH + L. acidophilus-treated group; G4: DMH + AYE-treated group; G5: DMH + L. acidophilus and AYE-treated group. A significant reduction (p < 0.05) in leukocyte DNA damage and in colonic cell proliferation was observed after the first DMH administration in G3 (probiotic), G4 (prebiotic) and G5 (synbiotic) groups. In this moment, a significant increase (p < 0.05) in colonic apoptosis was also observed in G3 (probiotic) and G5 (synbiotic) groups. In special, at five months after DMH administrations, a significant reduction (p < 0.05) in ACF development was observed in G3 (probiotic), G4 (prebiotic) and G5 (synbiotic) groups. Incidence of colon tumors was lower at five months in G4 (prebiotic) and G5 (synbiotic) groups but not in eight months after DMH administrations. In conclusion, the findings suggest that the oral treatments have potential effects as a chemopreventive agent against colon carcinogenesis on an early stage of tumor development.     

Functionality of freeze-dried L. casei cells immobilized on wheat grains

Lactobacillus casei cells were immobilized on wheat grains and the effect of nine cryoprotectants during freeze-drying was investigated. Survival and fermentative activity of the freeze-dried immobilized biocatalysts was studied by monitoring pH, lactic acid and lactose content in successive fermentations batches of both synthetic lactose medium and milk. Freeze-dried L. casei cells immobilized on wheat grains without using cryoprotectants resulted in high cell survival and metabolic activity. The same biocatalysts were stored at room temperature for 9 months and at 4 °C and −18 °C for 12 months. Reactivation of the stored biocatalysts was carried out in synthetic lactose medium. Storage at room and low temperatures (4 °C and −18 °C) resulted in about 5.11, 4.9 and 4.3 final pH respectively during fermentations, indicating the suitability of the immobilized biocatalysts for the production of mild and low pH dairy products. The immobilization of a probiotic microorganism, such as L. casei, on boiled wheat which contains prebiotic compounds might provide a potential synbiotic preparation.     

Microencapsulation of Lactobacillus acidophilus ATCC 43121 with prebiotic substrates using a hybridisation system

The objective of this study was to evaluate the effects of prebiotic substrates on the growth of Lactobacillus acidophilus ATCC 43121 and to investigate the utilisation of these prebiotic substrates as coating materials for microencapsulation. The cell growth of L. acidophilus ATCC 43121 was significantly increased in the presence of fructooligosaccharide, lactulose and raffinose. The microencapsulation of L. acidophilus ATCC 43121 cells was carried out by dry surface reforming process (hybridisation) using the selected prebiotic substrates and the enteric coating material, Sureteric^TMsans. Scanning and transmission electron microscopy revealed that the double‐microencapsulated bacteria exhibited smooth, rounded external surfaces, with a thick external coating composed of the prebiotic substrates and the Sureteric. The acid (artificial gastric juice) or heat tolerance (55 °C) of the double‐microencapsulated preparations (prebiotic and enteric coating) was significantly higher than that of the uncoated and single‐coated (enteric coating) preparation at prolonged acid (5 h) or heat exposure (3 h). On the contrary, no significant differences were found in salt tolerance. During the storage up to 20 days at 25 and 37 °C, the stability of L. acidophilus ATCC 43121 was significantly improved by double‐microencapsulation.     

Influence of probiotic strains added to cottage cheese on generation of potentially antioxidant peptides,anti-listerial activity,and survival of probiotic microorganisms in simulated gastrointestinal conditions

Our objective was to evaluate the viability of probiotic microorganisms added to cottage cheese under simulated gastrointestinal conditions, the release of potentially-antioxidant peptides, and their antimicrobial effect on Listeria monocytogenes. Cottage cheeses were prepared in triplicate, incorporating Lactobacillus casei, Lactobacillus rhamnosus GG, the commercial mix YO-MIX™ 205, or a control without probiotic addition. The probiotic population remained at >10⁶ cfu g⁻¹ during 28 days of storage at 8 °C. Cheeses made with added probiotics showed an increased metabolic activity with higher levels of lactic and acetic acids. Higher numbers of potentially bioactive peptides were observed in cheeses added with probiotics. L. monocytogenes population was reduced by about one log cycle after 20 days of storage, in cheeses with probiotics added. Our results indicate that cottage cheese is a good vehicle for probiotic bacteria.     

Discrimination of dairy industry isolates of the Lactobacillus casei group

Lactobacilli are a major part of the microflora of the gut and of many fermented dairy products, and are found in a variety of environments. Lactobacillus casei, Lactobacillus paracasei, Lactobacillus rhamnosus, and Lactobacillus zeae form a closely related taxonomic group within the facultatively heterofermentative lactobacilli. The classification and nomenclature of these bacteria are controversial. In this study, relationships between these species were investigated using type strains and dairy industry isolates examined with DNA-based techniques and conventional carbohydrate use tests. Carbohydrate use patterns gave poor discrimination of some species, but DNA PCR using specific primers targeted to sequences of the 16S rRNA gene discriminated 4 types consistent with the currently recognized species. Pulsed-field agarose gel electrophoresis of chromosomal NotI restriction fragments identified 18 different band patterns from 21 independent Lactobacillus isolates and confirmed the identity of L. casei strains from 2 culture collections (CSCC 5203 and ASCC 290), both representing the type strain of L. casei. Some isolates were reclassified as L. rhamnosus, suggesting that the prevalence of L. rhamnosus as a natural component of the microflora of dairy foods and dairy environments has previously been underestimated. These methods can provide a practical basis for discrimination of the species and identification of individual industrial strains.