Presence Of Bile Salts Research Articles

Impact of pasteurization on the self-assembly of human milk lipids during digestion

Human milk is critical for the survival and development of infants. This source of nutrition contains components that protect against infections while stimulating immune maturation. In cases where the mother's own milk is unavailable, pasteurized donor milk is the preferred option. Although pasteurization has been shown to have minimal impact on the lipid and FA composition before digestion, no correlation has been made between the impact of pasteurization on the FFA composition and the self-assembly of lipids during digestion, which could act as delivery mechanisms for poorly water-soluble components. Pooled nonpasteurized and pasteurized human milk from a single donor was used in this study. The evolving FFA composition during digestion was determined using GC coupled to a flame ionization detector. In vitro digestion coupled to small-angle X-ray scattering was utilized to investigate the influence of different calcium levels, fat content, and the presence of bile salts on the extent of digestion and structural behavior of human milk lipids. Almost complete digestion was achieved when bile salts were added to the systems containing high calcium to milk fat ratio, with similar structural behavior of lipids during digestion of both types of human milk being apparent. In contrast, differences in the colloidal structures were formed during digestion in the absence of bile salt because of a greater amount of FFAs being released from the nonpasteurized than pasteurized milks. This difference in FFAs released from both types of human milk could result in varying nutritional implications for infants.

The human bile salt sodium deoxycholate induces metabolic and cell envelope changes in Salmonella Typhi leading to bile resistance.

Introduction. Salmonella enterica serovar Typhi (S. Typhi) is the etiological agent of typhoid fever. To establish an infection in the human host, this pathogen must survive the presence of bile salts in the gut and gallbladder.Hypothesis. S. Typhi uses multiple genetic elements to resist the presence of human bile.Aims. To determine the genetic elements that S. Typhi utilizes to tolerate the human bile salt sodium deoxycholate.Methodology. A collection of S. Typhi mutant strains was evaluated for their ability to growth in the presence of sodium deoxycholate and ox-bile. Additionally, transcriptomic and proteomic responses elicited by sodium deoxycholate on S. Typhi cultures were also analysed.Results. Multiple transcriptional factors and some of their dependent genes involved in central metabolism, as well as in cell envelope, are required for deoxycholate resistance.Conclusion. These findings suggest that metabolic adaptation to bile is focused on enhancing energy production to sustain synthesis of cell envelope components exposed to damage by bile salts.

The role of probiotic exopolysaccharides in adhesion to mucin in different gastrointestinal conditions

The presence of exopolysaccharides (EPS), a type of biomacromolecules, on the surface of probiotics play an important role in mucoadhesion, and it can be severely influenced by environments during gastrointestinal transit. In this study, the impact of gastrointestinal factors on surface properties of two probiotics (Lactobacillus rhamnosus GG and Pediococcus pentosaceus LI05) was investigated. Probiotic suspensions had relatively high viscosities and exhibited pronounced shear-thinning behavior due to the presence of EPS. The ζ-potential of both probiotics was relatively low and was not believed to play an important role in mucoadhesion. Compared to the control, the adhesive forces tended to decrease in the presence of gastric acids but increase in the presence of bile salts, since bile salts led to a thicker more open EPS layer compared to gastric acids. Although the functional groups of EPS in both probiotics are similar according to the study by FT-IR spectroscopy, the molecular weight of purified EPS in LI05 was much higher, ranging from 10,112 Da to 477,763 Da, which may contribute to higher rupture length in LI05 group. These results suggest that probiotic-mucin interactions are governed by the compositions and changes in the EPS of the probiotics in different gastrointestinal conditions, which contribute to a better understanding of the mucoadhesive behavior of the probiotics in the GIT.

Growth stimulation of Clostridium butyricum in the presence of Lactobacillus brevis JL16 and Lactobacillus parabuchneri MH44

Certain strains of Clostridium butyricum exhibit characteristics of probiotics that are now sold in eastern Asian countries such as Korea and Japan. Integral improvement in C. butyricum functions can be achieved in the presence of Lactobacillus spp. through the process of attentive selection. This study aimed to select specific strains of lactic acid bacteria that could synergistically enhance the probiotic functions of C. butyricum. The supernatants of 249 lactic acid bacteria were examined, and we observed that 24 strains did not inhibit the growth of C. butyricum. Additionally, 4 of these 24 strains induced over 2-fold promotion in C. butyricum growth rates during co-culture with this bacterial strain. This growth promotion was verified using qPCR. In particular, Lactobacillus brevis JL16 and Lactobacillus parabuchneri MH44 stimulated C. butyricum more effectively than did other strains. We determined the level of buk (butyrate kinase) expression, the survival rate in the presence of bile salt, the ability of auto-aggregation, and the survival rate after freeze-drying.

Impact of Swelling of Spray Dried Dispersions in Dissolution Media on their Dissolution: An Investigation Based on UV Imaging

Impact of SDD-dissolution medium interactions on the swelling and dissolution of spray dried dispersions (SDDs) was investigated using UV imaging by monitoring SDD swelling in situ, along with correlating of the swelling with the micro-dissolution and intrinsic dissolution of SDDs. SDDs of ketoconazole or indomethacin with three polymers: polyvinylpyrrolidone (PVP), hydroxypropyl cellulose (HPC), and hydroxypropyl methylcellulose acetate succinate (HPMC-AS) were prepared for the study. Dissolution media employed for assessing swelling and dissolution include water, acetate buffer, phosphate buffer, fasted state simulated intestinal fluid (FaSSIF), and fed state simulated intestinal fluid (FeSSIF), in which influence of polymers and drugs together with the physical-chemical properties of dissolution media (pH, and the presence of sodium taurocholate and lecithin) on SDD swelling and dissolution was evaluated. It appears that hydrophilic and hydrophobic properties of polymers can significantly impact SDD swelling and thus the dissolution. Furthermore, properties of dissolution media such as pH as well as presence of bile salts and lecithin seems to affect SDD swelling and dissolution as well. Throughout the text, thermodynamic swelling of polymers was used to interpret SDD dissolution behavior. Finally, practical implication of polymer swelling on dissolution was discussed.

Advancements in the Pharmaceutical Applications of Probiotics: Dosage Forms and Formulation Technology.

Probiotics have demonstrated their high potential to treat and/or prevent various diseases including neurodegenerative disorders, cancers, cardiovascular diseases, and inflammatory diseases. Probiotics are also effective against multidrug-resistant pathogens and help maintain a balanced gut microbiota ecosystem. Accordingly, the global market of probiotics is growing rapidly, and research efforts to develop probiotics into therapeutic adjuvants are gaining momentum. However, because probiotics are living microorganisms, many biological and biopharmaceutical barriers limit their clinical application. Probiotics may lose their activity in the harsh gastric conditions of the stomach or in the presence of bile salts. Moreover, they easily lose their viability under thermal or oxidative stress during their preparation and storage. Therefore, stable formulations of probiotics are required to overcome the various physicochemical, biopharmaceutical, and biological barriers and to maximize their therapeutic effectiveness and clinical applicability. This review provides an overview of the pharmaceutical applications of probiotics and covers recent formulation approaches to optimize the delivery of probiotics with particular emphasis on various dosage forms and formulation technologies.

Investigation of Escherichia coli O157:H7 Survival and Interaction with Meal Components during Gastrointestinal Digestion.

Escherichia coli O157:H7 is responsible for foodborne poisoning, incriminating contaminated animal food and especially beef meat. This species can survive in the digestive tract, but, up to now, very few studies have considered its survival during the gastrointestinal digestion of meat. The present study aimed to investigate the survival of the pathogenic strain E. coli O157:H7 CM454 during the gastrointestinal digestion of ground beef meat and its interactions with meal components using a semidynamic digestive model. The CM454 strain in meat survived throughout digestion despite acidic pH (pH 2) and the presence of bile salts. The addition of nitrite and ascorbate in the digestion medium led to a decrease in strain survival. During digestion, a release of free iron was observed, which was accentuated in the presence of the CM454 strain. In addition, the strain modified the Fe2+/Fe3+ ratio, in favor of Fe2+ compared to the noninoculated meat sample. In the presence of nitrite, nitroso compounds such as nitrosamines, nitrosothiols, and nitrosylheme were formed. E. coli O157:H7 CM454 had no impact on N-nitrosation but seemed to decrease S-nitrosation and nitrosylation.

Ricotta whey supplemented with gelatin and collagen for the encapsulation of probiotic lactic acid bacteria

The aim of the present study was to evaluate the viability of probiotic bacteria Lactobacillus acidophilus (LA-5)® and Bifidobacterium lactis (BB-12)® encapsulation using spray drying (SD) with ricotta whey supplemented with gelatin and hydrolyzed collagen as encapsulating material. Following previous experiments, these gelatin:collagen ratios were defined: 7:3 (gelatin:collagen) for L. acidophilus LA-5 and 9:1 for B. lactis BB-12, which had reduced bacterial counts of 0.46 and 1.26 log Colony-Forming Units (CFU)/g, respectively. There was a viability loss of 0.70 log CFU/g and 0.34 log CFU/g for LA-5 and BB-12, respectively, throughout storage (30 days, 25 ºC). When exposed to the simulated gastric juice, encapsulated LA-5 and BB-12 had higher survival rates (89.91 and 95.83%, respectively) than non-encapsulated microorganisms under the same conditions (54.78 and 57.27%, respectively). In the presence of bile salts, encapsulated LA-5 and BB-12 had survival of 77.44% and 51.05%, respectively, while free cells showed rates of over 99%. After 30 days, these rates decreased to 71.07 and 50.60%, for encapsulated LA-5 and BB-12, respectively. Therefore, ricotta whey associated to gelatin and hydrolyzed collagen can be considered a potential encapsulating agent for the SD of probiotic dairy bacteria.

Bile Salts Regulate Zinc Uptake and Capsule Synthesis in a Mastitis-Associated Extraintestinal Pathogenic Escherichia coli Strain.

Extraintestinal pathogenic Escherichia coli (ExPEC) strains are major causes of urinary and bloodstream infections. ExPEC reservoirs are not completely understood. Some mastitis-associated E. coli (MAEC) strains carry genes associated with ExPEC virulence, including metal scavenging, immune avoidance, and host attachment functions. In this study, we investigated the role of the high-affinity zinc uptake (znuABC) system in the MAEC strain M12. Elimination of znuABC moderately decreased fitness during mouse mammary gland infections. The ΔznuABC mutant strain exhibited an unexpected growth delay in the presence of bile salts, which was alleviated by the addition of excess zinc. We isolated suppressor mutants with improved growth in bile salts, several of which no longer produced the K96 capsule made by strain M12. The addition of bile salts also reduced capsule production by strain M12 and ExPEC strain CP9, suggesting that capsule synthesis may be detrimental when bile salts are present. To better understand the role of the capsule, we compared the virulence of mastitis strain M12 with that of its unencapsulated ΔkpsCS mutant in two models of ExPEC disease. The wild-type strain successfully colonized mouse bladders and kidneys and was highly virulent in intraperitoneal infections. Conversely, the ΔkpsCS mutant was unable to colonize kidneys and was unable to cause sepsis. These results demonstrate that some MAEC strains may be capable of causing human ExPEC illness. The virulence of strain M12 in these infections is dependent on its capsule. However, capsule may interfere with zinc homeostasis in the presence of bile salts while in the digestive tract.

The Effects of Food on Cannabidiol Bioaccessibility.

Cannabidiol (CBD) is a hydrophobic non-psychoactive compound with therapeutic characteristics. Animal and human studies have shown its poor oral bioavailability in vivo, and the impact of consuming lipid-soluble CBD with and without food on gut bioaccessibility has not been explored. The purpose of this research was to study the bioaccessibility of CBD after a three-phase upper digestion experiment with and without food, and to test lipase activity with different substrate concentrations. Our results showed that lipase enzyme activity and fatty acid absorption increased in the presence of bile salts, which may also contribute to an increase in CBD bioaccessibility. The food matrix used was a mixture of olive oil and baby food. Overall, the fed-state digestion revealed significantly higher micellarization efficiency for CBD (14.15 ± 0.6% for 10 mg and 22.67 ± 2.1% for 100 mg CBD ingested) than the fasted state digestion of CBD (0.65 ± 0.7% for 10 mg and 0.14 ± 0.1% for 100 mg CBD ingested). The increase in bioaccessibility of CBD with food could be explained by the fact that micelle formation from hydrolyzed lipids aid in bioaccessibility of hydrophobic molecules. In conclusion, the bioaccessibility of CBD depends on the food matrix and the presence of lipase and bile salts.

Perspectives of Bacillus coagulans MTCC 5856 in the production of fermented dairy products

Probiotic bacteria protect against gastroenteritis, promote toxin reduction, cholesterol reduction, improved digestion and good function, mineral bioavailability enhancement. Bacterial strains, including Lactobacillus and Bifidobacterium, are generally used in probiotic food production. However, they are weakly resistant to the stomach's aggressive environment and high temperature, which can result in significant loss of viable probiotic microorganisms. Application of spore-forming bacteria Bacillus coagulans MTCC 5856 allows developing an innovative natural dairy fermented product with high probiotic microorganism viability (p < 0.05) during the technological process, storage period, at different pH values, and in the presence of bile salts when examining in vitro. Due to the low caseolytic activity of Bacillus coagulans, the proper ratio and fermentation temperature with the use of auxiliary starter culture Streptococcus thermophilus were established. The addition of milk protein improves the rheological characteristics of the product. Bacillus coagulans and Streptococcus thermophilus maintained more than 8 Log10 CFU/g of viable microorganisms during the product storage within 60 days. The use of Bacillus coagulans allows increasing the fermented product's antioxidant activity versus the antioxidant activity of the product when Streptococcus thermophilus is used alone. The results showed that the fermented dairy product itself to be an excellent carrier of Bacillus coagulans.

Physiological and Genomic Analysis of Bacillus pumilus UAMX Isolated from the Gastrointestinal Tract of Overweight Individuals.

The study aimed to evaluate the metabolism and resistance to the gastrointestinal tract conditions of Bacillus pumilus UAMX (BP-UAMX) isolated from overweight individuals using genomic tools. Specifically, we assessed its ability to metabolize various carbon sources, its resistance to low pH exposure, and its growth in the presence of bile salts. The genomic and bioinformatic analyses included the prediction of gene and protein metabolic functions, a pan-genome and phylogenomic analysis. BP-UAMX survived at pH 3, while bile salts (0.2–0.3% w/v) increased its growth rate. Moreover, it showed the ability to metabolize simple and complex carbon sources (glucose, starch, carboxymethyl-cellulose, inulin, and tributyrin), showing a differentiated electrophoretic profile. Genome was assembled into a single contig, with a high percentage of genes and proteins associated with the metabolism of amino acids, carbohydrates, and lipids. Antibiotic resistance genes were detected, but only one beta-Lactam resistance protein related to the inhibition of peptidoglycan biosynthesis was identified. The pan-genome of BP-UAMX is still open with phylogenetic similarities with other Bacillus of human origin. Therefore, BP-UAMX seems to be adapted to the intestinal environment, with physiological and genomic analyses demonstrating the ability to metabolize complex carbon sources, the strain has an open pan-genome with continuous evolution and adaptation.

Isolation and Characterization of Probiotic Bacillus subtilis MKHJ 1-1 Possessing L-Asparaginase Activity

The purpose of this study was to isolate functional Bacillus strains from Korean fermented soybeans and to evaluate their potential as probiotics. The L-asparaginase activity of MKHJ 1-1 was the highest among 162 Bacillus strains. This strain showed nonhemolysis and did not produce β-glucuronidase. Among the nine target bacteria, MKHJ 1-1 inhibited the growth of Escherichia coli, Pseudomonas aeruginosa, Shigella sonnei, Shigella flexneri, Klebsiella pneumoniae, Staphylococcus aureus, and Bacillus cereus. 16S rRNA gene sequence analysis resulted in MKHJ 1-1 identified as Bacillus subtilis subsp. stercoris D7XPN1. As a result of measuring the survival rate in 0.1% pepsin solution (pH 2.5) and 0.3% bile salt solution for 3 h, MKHJ 1-1 exhibited high acid resistance and was able to grow in the presence of bile salt. MKHJ 1-1 showed outstanding autoaggregation ability after 24 h. In addition, its coaggregation with pathogens was strong. Therefore, MKHJ 1-1 is a potential probiotic with L-asparaginase activity and without L-glutaminase activity, suggesting that it could be a new resource for use in the food and pharmaceutical industry.

TolCV1 Has Multifaceted Roles During Vibrio vulnificus Infection.

RtxA1 is a major cytotoxin of Vibrio vulnificus (V. vulnificus) causing fatal septicemia and necrotic wound infections. Our previous work has shown that RpoS regulates the expression and secretion of V. vulnificus RtxA1 toxin. This study was conducted to further investigate the potential mechanisms of RpoS on RtxA1 secretion. First, V. vulnificus TolCV1 and TolCV2 proteins, two Escherichia coli TolC homologs, were measured at various time points by Western blotting. The expression of TolCV1 was increased time-dependently, whereas that of TolCV2 was decreased. Expression of both TolCV1 and TolCV2 was significantly downregulated in an rpoS deletion mutation. Subsequently, we explored the roles of TolCV1 and TolCV2 in V. vulnificus pathogenesis. Western blot analysis showed that RtxA1 toxin was exported by TolCV1, not TolCV2, which was consistent with the cytotoxicity results. Furthermore, the expression of TolCV1 and TolCV2 was increased after treatment of the host signal bile salt and the growth of tolCV1 mutant was totally abolished in the presence of bile salt. A tolCV1 mutation resulted in significant reduction of V. vulnificus induced-virulence in mice. Taken together, TolCV1 plays key roles in RtxA1 secretion, bile salt resistance, and mice lethality of V. vulnificus, suggesting that TolCV1 could be an attractive target for the design of new medicines to treat V. vulnificus infections.

Probiotic and safety assessment of Lactobacillus strains isolated from Lebanese Baladi goat milk

Microbiological and physicochemical parameters of Lebanese Baladi goat milk from six farms were evaluated and 28 Lactobacillus strains were isolated and examined in vitro for their probiotic potential. Goat milk showed a balanced physicochemical composition while variable LAB counts were observed among samples. All isolates were identified as Lactobacillus rhamnosus. They exhibited diverse susceptibility to commonly used antibiotics, none was haemolytic and showed variable antimicrobial activity towards a range of spoilage and pathogenic bacteria. All strains remained unaffected at pH 3 and in the presence of bile salts (0.5%, w/v) for 3 h exhibiting also a partial bile salt hydrolase activity. Selected strains showed low adhesion to HT-29 and Caco-2 cells. Decrease in COX2 mRNA levels and a tendency to an increase in IL10 expression in human monocytes were noticed. This is the first report about probiotic and safety features of Lb. rhamnosus strains isolated from Lebanese Baladi goat milk.

In vitro Characterization of Enterococcus faecium strain LCM08 as a probiotic

Background: Under the present situations, where health improvement has become the major concern, food supplements, augmenting health is a matter of interest. Presently, the concept of "functional foods" possessing medicinal attributes has been reborn as probiotics. Acid-tolerant and Gram-positive Lactic acid bacteria (LAB), being the major class of probiotics, possess health-promoting characteristics, provide better health with a robust immune system, and treat various digestive and neurological disorders. Hence, the aim of the present study was the isolation and identification of LAB.&#x0D; Methodology: The LAB were isolated from various sources, including food products and clinical samples. Enterococcus faecium LCM08 being the most potent isolate tested for probiotic traits, including viability under acidic conditions, biological concentrations of bile salts and enzymes.&#x0D; Results: A total of fifty-four strains were isolated, of which 7.2% showed broad-spectrum inhibition against the tested pathogens. Amongst them, Enterococcus faecium LCM08 owing to its broad-spectrum antagonism, when tested for its ability to withstand acidic conditions, displayed 63.58% viability and 72.19% survivability in the presence of bile salts. Moreover, strain sustained in the presence of digestive enzymes including protease (94.65%), trypsin (93.57%) and pancreatin (75.0%) as well as exhibited growth at temperatures ranging between 25˚C and 30˚C where the maximum viable counts recorded as 95% and 96.4%. The strain also produced antimicrobial metabolites at neutral pH. However, elevated temperatures (45˚C-50˚C) inhibited the production of bacteriocin-like inhibitory substances.&#x0D; Conclusion: The preliminary investigations revealed that Enterococcus faecium LCM08 possesses the key attributes pre-requisite for a probiotic candidate.

Evaluation of Cholesterol Lowering Efficacy and Antibacterial Potential of Probiotics: An In vitro Study

Background and Objectives: Probiotics are nonpathogenic and beneficial viable microorganisms that exhibit potential health welfare for human beings. Probiotics are found in various food products. They also occur as natural microflora in the intestine of mammals. Main goal of this study was to isolate probiotics conferring antibacterial activity and cholesterol lowering ability from different fruits. Materials and Method: Present research reveals the usefulness of probiotics, in which twenty one bacterial cultures were isolated from different fruit samples including figs, coconut water and grapes. These strains were explored for their antibacterial and cholesterol reduction ability by conducting in vitro experiments. Results and Discussion: Among twenty one isolates, nine probiotic cultures FgC2, FgC7, FgC14, G2C5, G1C, GrC18 and StCW showed maximum antibacterial activity against different human clinical pathogens. This suggests that these microbes produce inhibitory metabolites which are extracellular and diffusible. For cholesterol assimilation assay, six strains FgC2, FgC7, FgC12, FgC13, GrC7 and GrC18 presented remarkable cholesterol lowering efficacy (up to 98%) when grown in the presence of bile salts. Only potential probiotic cultures were identified and characterized as lactic acid bacteria (LAB), on the basis of Bergey’s Manual of Determinative Bacteriology. Conclusion: Thus, this study is helpful to exploit the bioactive and therapeutic potential of beneficial microorganisms so that they can be utilized in the generation of functional food and other health promoting products.

Identification and characterisation of the lactic acid bacteria associated with the traditional fermentation of dairy fermented product.

The aim of this research was to identify the key lactic acid bacteria associated with the fermentation of dairy traditional fermented products for developing starter cultures for controlled fermentation. A total of 100 lactic acid bacteria (LAB) were isolated from dairy traditional fermented products. Samples were obtained from eight producers in the South East of Nigeria. Isolates were identified by phenotypic and genotypic techniques including rep-PCR genotyping and sequencing of the 16S rRNA, pheS and rpoA genes. Isolates were characterised for antimicrobial activity against foodborne pathogens, exopolysaccharide (EPS) production and survival at low pH and in the presence of bile salts. All isolates clustered into 11 distinct rep-PCR groups and were identified as Lactobacillus fermentum (40%), Lactobacillus delbrueckii (23%), Streptococcus thermophilus (22%), Streptococcus infantarius (10%), Lactobacillus senioris (2%), Leuconostoc pseudomesenteriodes (2%) and Enterococcus thailandicus (1%). Lactobacillus fermentum showed a broad spectrum antimicrobial activity and survival at low pH, while Lactobacillus delbrueckii was able to tolerate low pH and produce EPS. All isolates survived in vitro exposure to 1% (w/v) bile salts over a 3-h period. L. fermentum, L. delbrueckii and S. thermophilus could be used to simulate the fermentation of dairy traditional fermented products.

Bactérias do ácido lático potencialmente probióticas isoladas de leite não pasteurizado

Algumas Bactérias do Ácido Lático (BAL), quando ingeridas em quantidades adequadas, são capazes de impactar positivamente o hospedeiro, sendo consideradas probióticas. Para serem utilizadas, essas bactérias devem ter sua identidade conhecida e apresentar características específicas. Nesse estudo, BAL foram isoladas a partir de amostras de leite não pasteurizado e caracterizadas in vitro quanto ao potencial probiótico. Após isolamento, as colônias foram analisadas por coloração de Gram e teste de catalase; DNA total foi extraído e o rDNA 16S foi amplificado e sequenciado. Análise filogenética foi realizada para reconstrução da história evolutiva dos isolados. Os isolados foram avaliados quanto à resistência ao pH ácido e à presença de sais biliares. A atividade antagonista das bactérias isoladas foi avaliada utilizando teste de sobrecamada e o perfil de suscetibilidade a antimicrobianos foi realizado pelo método de disco difusão. Do total de 13 bactérias isoladas, três foram caracterizadas como bastonetes Gram-positivos e catalase negativos, apresentando 99% de identidade com Lactobacillus casei, Lactobacillus paracasei e Weisella paramesenteroides. Os isolados apresentaram resistência in vitro ao estresse ácido e à presença de sais biliares; mostraram perfil de resistência semelhante aos antimicrobianos e capacidade de inibir o crescimento de bactérias potencialmente patogênicas, como Staphylococcus saprophitycus, Escherichia coli, Staphylococcus aureus, Enterococcus faecalis e Enterococcus faecium. Diante das características comprovadas, as bactérias láticas isoladas neste trabalho apresentam potencial probiótico.

Characterization of wild yeasts isolated from artisan dairies in the Marche region, Italy, for selection of promising functional starters

Ninety-two yeasts isolated from cheeses and different dairies in the Marche region (Italy) were identified and characterized as potential functional co-starter cultures. The prevalent isolates were Debaryomyces hansenii (58%), Candida zeylanoides (25%) and Yarrowia lipolytica (5.5%), while other species belonging to the Candida, Kluyveromyces, Moniliella and Yamadazyma genera were minorities. The yeasts identified were subjected to typing analysis with the purpose of clustering the biotypes to detect the strain specificity for each dairy. Furthermore, the occurrence of some functional and/or probiotic properties was evaluated. D. hansenii, C. zeylanoides and Y. lipolytica showed 16, 4 and 2 different biotypes, respectively. Y. lipolytica biotype II and Candida parapsilosis biotype I exhibited high antioxidant activities. The unique Kluyveromyces lactis biotype showed a minimal ability to grow in the presence of bile salts at 37 °C and pH 2.5, but it exhibited high antioxidant activity. Most of the D. hansenii and C. zeylanoides biotypes showed relevant preliminary probiotic and technological traits. Thus, considering these preliminary evaluations, selected strains of C. zeylanoides, Y. lipolytica and K. lactis could be proposed in association with lactic acid bacteria as innovative co-starters that are able to develop functional cheeses characterized by a distinctive aroma.