Streptococcus Thermophilus Research Articles

The effect of Lactobacillus acidophilus,Streptococcus thermophilus, and Bifidobacterium longum probiotics on bilirubin levels of neonates with hyperbilirubinemia

Hyperbilirubinemia, a common illness in newborns that can lead to hospital readmission, has been treated with blue light phototherapy. This treatment, either on its own or in combination with probiotics, has shown fast and significant decreases in bilirubin levels in the blood, helping to speed up the fading of jaundice. This study aims to examine the effects of combining phototherapy with probiotics containing Lactobacillus acidophilus, Streptococcus thermophilus, and Bifidobacterium longum on newborns with hyperbilirubinemia. The study was conducted at Sultan Agung Islamic Hospital (RSI Sultan Agung), Semarang, using a randomized controlled trial design. It included newborns who were hospitalized between August and November 2022. The control group was administered phototherapy, whereas the treatment group received both phototherapy and probiotics for 7 days. SPSS software analysis demonstrated a statistically significant reduction in average levels of total and indirect bilirubin in the intervention group (6.50 mg/dl and 7.20 mg/dl) compared to the control group (6.70 mg/dl and 7.48 mg/dl). These findings highlight the potential effectiveness of the combined approach in controlling hyperbilirubinemia. The study proposes using probiotics as a safe additional treatment for neonatal hyperbilirubinemia, showing that it is well-tolerated and safe for the participants. Although the combination of probiotics and phototherapy did not show a significant difference compared to phototherapy alone, it did result in a faster average decrease in hyperbilirubinemia. This could reduce the necessity for hospital readmissions to manage this condition. The findings underscore the potential of probiotics as a helpful supplement to established treatment methods for newborn hyperbilirubinemia.

Microbial evaluation of cooked fufu sold in some major markets in Owo metropolis, Ondo state, Nigeria

Fufu (Cassava dough-like food) is one of Nigeria's most consumed staple foods, particularly in the southern parts of the country. This study aims to detect and quantify the microorganisms in cooked fufu sold in major Owo, Ondo State marketplaces. Freshly cooked fufu samples of about 50/gram wrapped in nylon were aseptically collected from sellers in three major Owo markets and transported to the Federal University of Technology, Akure (FUTA) Crop, Soil, and Pest Management Department lab for analysis. For bacteria, Nutrient Agar (NA) plates were incubated at 37+2ºC for 24 hours, whereas PDA plates for yeast and mould were incubated at 27+2ºC for 48 hours. Count and record the colonies generating spores (cfu/g) from viable bacterium cells and fungal spores per gram of each fufu sample after incubation. Purified cultures of each isolate were obtained through subcultures and stored at 4 ºC for biochemical testing. Cooked fufu samples found mostly lactic acid bacteria like Lactobacillus plantarum, L. fermentum, L. brevis, Leuconostoc mesenteroides, Streptococcus thermophiles, S. mutans, Pediococcus cerevisiae, Staphylococcus hominis, Bacillus pumilus, acidophilus, L. lactis, Micrococcus spp., B. subtilis, Diplococcus spp, S. epidermidis, and Bifidobacterium and two yeasts, Saccharomyces cerevisiae and Zygosaccharomyces spp. Some main markets in Owo metropolis sold cooked fufu samples with bacterial loads ranging from 0.2 to 2.3 × 107 CFU/g, and yeast loads from 1.6 to 4.55 × 107 CFU/g. Good hygiene can increase the safety and quality of cooked fufu sold at Owo main markets and lower the danger of food-borne illnesses.

Development of optimized functional clove fortified probiotic yoghurt.

We focused on assessing the antimicrobial effects of functional yoghurts supplemented with clove and probiotics. The formulation of aqueous clove extract (ACE) incorporated with probiotic yoghurt (Streptococcus thermophilus, Lactobacillus bulgaricus, and Lactococcus lactis) was optimised in terms of aqueous clove extract concentrations (2.5-7.5% v/v), fermentation temperature (32-42°C), and total culture concentration (1.5-4.5% v/v). pH, titratable acidity, syneresis, water holding capacity, viscosity, springiness, color difference, lactic acid bacteria viability, and the antibacterial property of 17 runs were determined as responses using Box-Behnken design. The results indicate that elevated ACE concentration leads to a significant (p < 0.05) increase in titratable acidity, antibacterial effectiveness (against K. pneumoniae and P. aeruginosa), springiness, and color profile. Conversely, an elevated fermentation temperature significantly (p < 0.05) reduces pH and L. bulgaricus viability (log CFU/mL). Additionally, there is a significant (p < 0.05) decline in S. thermophilus and L. lactis viability (log CFU/mL) as well as springiness with an increased culture concentration. The optimal conditions identified are 7.5% (v/v) ACE concentration, a fermentation temperature of 36.6°C (37°C), and a total culture concentration of 4.5% (v/v), resulting in a 79% desirability score. The spectra of components were mainly obtained at wavelength of 3258cm-1, 1636cm-1 and 1075cm-1 in Fourier transform infrared (FTIR) spectroscopy of optimized functional yoghurt. Where, 3258cm-1 corresponds to the stretching vibration of O-H (hydroxyl) groups, 1636cm-1 corresponds to the C=O (carbonyl) stretching vibration, and 1075cm-1 corresponds to the C-O (ether or alcohol) stretching vibration.

Effects of yeast screened from traditional fermented milk on commercial fermented milk as adjunct flavor culture

Two yeast strains with better overall flavor quality were isolated and screened from traditional fermented milk in western Sichuan, identified as Kluyveromyces marxianus and Saccharomyces cerevisiae, and their role as adjunct cultures in fermented milk was studied. Fermented milk (LS, LSK, LSS and LSKS) were respectively inoculated with Lactobacillus bulgaricus + Streptococcus thermophiles (LS), LS + K. marxianus, LS + S. cerevisiae, and LS + K. marxianus + S. cerevisiae. The obtained LSKS has the best overall quality with moderate ethanol and ester aroma, rich in fermentation aroma, delicate taste, and the highest acidity (87.52 ± 0.44 °T), viscosity (418.18 ± 18.73 mPa·s), and organic acid content (449.736 mg/100 g), as well as the abundant ethyl esters (ethyl ocanoate, ethyl caprate, ethyl hexanoate). Non-targeted metabolomics revealed the metabolites differences for LSKS versus LS. Sixty-five metabolites upregulated and seventy-two metabolites downregulated, which were significantly enriched in arginine biosynthesis and glycerophospholipid metabolism pathway. A large number of short peptides were upregulated, and calenduloside G methyl ester has the potential to be used as a differential biomarker. This study provides a theoretical basis for the application potential of K. marxianus SY11 and S. cerevisiae SY32 to stimulate fermentation with LS as adjunct flavor cultures in commercial fermented milk.

Orally administered Streptococcus thermophilus YIT 2001 is a vehicle for the delivery of glutathione, a reactive reduced thiol, to the intestine.

We aimed to analyze the behavior of cellular glutathione of Streptococcus thermophilus strain YIT 2001 (ST-1) in the gastrointestinal environment to understand how orally administered glutathione in ST-1 cells is delivered stably to the intestine in a reactive form, which is essential for its systemic bioavailability against lipid peroxidation. Intracellular glutathione was labeled with L-cysteine-containing stable isotopes. ST-1 cells from fresh culture or lyophilized powder were treated with simulated gastric and intestinal juices for 60 min each. The release of intracellular glutathione in digestive juices was quantified via LC-MS/MS. Most of the cellular glutathione was retained in the gastric environment and released in response to exposure to the gastrointestinal environment. During digestion, the membrane permeability of propidium iodide increased significantly, especially when cells were exposed to cholate, without change in the cell wall state. ST-1 cells act as vehicles to protect intracellular reactive components, such as glutathione, from digestive stress, and release them in the upper intestine owing to the disruption of membrane integrity induced by bile acid.

Unveiling the hidden potential of nisin-permeabilized Streptococcus thermophilus as proteolysis accelerant during cheese ripening

Proteolysis is the most significant primary ripening process in cheese, as it produces amino acids that serve as precursors for various flavor compounds. Therefore, the degree of proteolysis is an important indicator of cheese ripening. Here, the potential of nisin-permeabilized lactic acid bacteria as proteolysis accelerant during cheese ripening was explored. Both nisin-permeabilized Lactococcus lactis and Streptococcus thermophilus cells could hydrolyze peptidase substrates lysyl–p-nitroanilide (Lys–pNA) and glycyl–pro–pNA [Gly–Pro–pNA] efficiently. The overall proteolytic capacity of permeabilized cells depended on nisin concentration, strain used, temperature, and pH. The best candidate, S. thermophilus ST057-1, could hydrolyze 80% Lys–pNA and 94% Gly–Pro–pNA at 30 °C and pH 7 when treated with 5 μg/mL nisin. Permeabilized ST057-1 cells, when used as a starter adjunct, led to a significant increase in free amino acid content in model cheeses, up to 1.5 times that of the reference cheese, within 80 days of cheese ripening. This study highlights the potential of utilizing nisin-permeabilized S. thermophilus cells as an adjunct to accelerate proteolysis during cheese ripening.

Production of high-antioxidant yoghurt using phycocyanin from microalgae Spirulina sp

Yoghurt is a functional food product widely used to improve the digestive system in the body. Yoghurt fermentation usually uses lactic acid bacteria from the Lactobacillus bulgaricus, Streptococcus thermophilus, and Lactobacillus casei. Phycocyanin has been used as a natural dye for food, cosmetics, and medicine. Phycocyanin is a complex protein that can be an anticancer, antioxidant, and immunity booster. In this study, the effect of the number of additions of phycocyanin, storage time, and time of addition of phycocyanin to the antioxidant activity, protein, and organoleptic properties of the yoghurt produced. In this study, cow milk was pasteurized and fermented to become a yoghurt. Afterwards, phycocyanine was added to the yoghurt before being stored and analyzed. Spectrophotometric analysis was utilized to determine the antioxidant activity and protein content. An organoleptic test using a Likert scale was conducted to determine the product's suitability to consumer tastes. Increased phycocyanin concentrations were added (0, 0.25, 0.5, and 0.75 wt. %), resulting in a decrease in IC50 value of 8855.53, 5843.371, and 4147.548 ppm, which shows an increase in antioxidant activity. At the level of consumer preference in terms of taste, the most preferred is a concentration of 0.5 wt. %, while in terms of colour and aroma, at a concentration of 0.25 wt. %. While the longer the storage time (1, 3, and 5 days), the increase in IC50 value of 2777.111, 5179.547, and 5916.884 ppm, and there was a decrease in protein content in the sample. For the level of consumer preferences in terms of taste and aroma, the most preferred is variable with a storage time of 1 day, and in terms of colour, the most preferred at five days storage. The IC50 value in the variable with the addition of phycocyanin after fermentation is less than the addition after fermentation, which is 5351.865 ± 1606 and 3897.162 ± 1678 ppm. The protein content is higher when adding phycocyanin before fermentation. While yoghurt with the addition phycocyanin before fermentation showed higer consumer preference in terms of taste and aroma. In contrast, the addition of phycocyanin after fermentation is preferred in terms of colour.

Microbial screening of animal skin bags used in traditional cheesemaking

Bouhezza is a traditional Algerian cheese produced and ripened in goatskin bags called Djeld. The aim of this study was to characterize the microbial ecosystem from Djeld (fresh and dried Djeld for making Bouhezza cheese) and the changes introduced by Lben microflora during its preparation and to identify its role in cheesemaking and its safety. Two replicates of fresh and dried skin bags (FS and DS) were sampled and analyzed before and after contact with Lben. The microbiological results showed no pathogens. Skins observed before the addition of Lben were less populated 2.86 and 3.20 log CFU cm−2 than skins examined after the addition of Lben (approximately 6.0 log CFU cm−2), suggesting a potential role of Lben in releasing some microorganisms into the skin during its time in the Djeld. However, an increase in mesophilic lactic acid bacteria and yeasts was observed in Lben after different periods of interaction with the skin. PCR-TTGE revealed the predominance of lactic acid bacteria (Lactiplantibacillus plantarum, Limosilactobacillus fermentum, Staphylococcus equorum subsp. linens, Lactococcus cremoris, Streptococcus thermophilus) and a few high-GC-content bacteria (Lacticaseibacillus paracasei, Brevibacterium casei). Transfer of several microbial species was observed between the goatskin bag biofilm and Lben during the overnight interaction. Bands corresponding to Lacticaseibacillus paracasei, Brevibacterium casei, and Lactobacillus delbrueckii subsp. lactis were detected in the fresh skin profile and in Lben after contact with the fresh skin. Lacticaseibacillus paracasei was found in dried skin and Lben after contact with dry skin. Lactobacillus helveticus and Enterococcus faecalis appeared in the Lben profile and persisted in Lben and the biofilm-covered dry skin after interaction. These results demonstrate an exchange of specific microbial populations between goatskin bag biofilm and Lben during the traditional preparation method, suggesting that the diversity of goatskin biofilm contributes to the microbial diversity of Lben used in the production of Bouhezza cheese.

Microbial interactions shape cheese flavour formation

Cheese fermentation and flavour formation are the result of complex biochemical reactions driven by the activity of multiple microorganisms. Here, we studied the roles of microbial interactions in flavour formation in a year-long Cheddar cheese making process, using a commercial starter culture containing Streptococcus thermophilus and Lactococcus strains. By using an experimental strategy whereby certain strains were left out from the starter culture, we show that S. thermophilus has a crucial role in boosting Lactococcus growth and shaping flavour compound profile. Controlled milk fermentations with systematic exclusion of single Lactococcus strains, combined with genomics, genome-scale metabolic modelling, and metatranscriptomics, indicated that S. thermophilus proteolytic activity relieves nitrogen limitation for Lactococcus and boosts de novo nucleotide biosynthesis. While S. thermophilus had large contribution to the flavour profile, Lactococcus cremoris also played a role by limiting diacetyl and acetoin formation, which otherwise results in an off-flavour when in excess. This off-flavour control could be attributed to the metabolic re-routing of citrate by L. cremoris from diacetyl and acetoin towards α-ketoglutarate. Further, closely related Lactococcus lactis strains exhibited different interaction patterns with S. thermophilus, highlighting the significance of strain specificity in cheese making. Our results highlight the crucial roles of competitive and cooperative microbial interactions in shaping cheese flavour profile.

UNIQUE MICROBIOME SIGNATURES RELATED TO CANCER SURVIVORSHIP AND COGNITIVE DECLINE IN OLDER ADULTS

Abstract Significant scientific advancements have resulted in new and effective therapies for patients with cancer. Although this leads to an increased cancer survivor population, there are several long-term side effects of cancer treatments, including a high risk of developing dementia. Emerging evidence shows that the gut microbiota significantly contributes to brain health and dementia pathology; however, its role in cancer treatment-related side effects, specifically in older adults, is not well known. Here, we used 110 participants from our MiaGB (Microbiome in aging Gut and Brain) consortium aged 60 years and older and analyzed their gut microbiome (using whole genome sequencing) with cognitive function (using Montreal Cognitive Assessment (MoCA) and MiniCog). We observed an 8% increase in cognitive impairment (CI) in cancer survivors compared to non-cancer participants (46% vs 38%, respectively). When only comparing cognitively healthy versus CI, the abundance of Escherichia coli was significantly higher in the CI group, while Streptococcus thermophilus was higher in the cognitively healthy group. Additionally, the abundances of Dorea sp. CAG 317, Ruminococcus gnavus, Roseburia faecis, and Eggerthella lenta were significantly increased in the gut of cancer survivors compared to non-cancer participants. Specifically, the abundance of Dorea sp. CAG 317 was increased in cancer survivors with CI. These findings suggest that unique microbiome signatures induced by cancer treatments may impair cognitive function. Furthermore, understanding the associations between the microbiota and cognitive function in cancer survivors will aid the development of therapeutics to combat cancer treatment-related side effects, which are a growing public health concern.

Metagenomic Insights into the Taxonomic and Functional Features of Traditional Fermented Milk Products from Russia.

Fermented milk products (FMPs) contain probiotics that are live bacteria considered to be beneficial to human health due to the production of various bioactive molecules. In this study, nine artisanal FMPs (kefir, ayran, khurunga, shubat, two cottage cheeses, bryndza, khuruud and suluguni-like cheese) from different regions of Russia were characterized using metagenomics. A metagenomic sequencing of ayran, khurunga, shubat, khuruud and suluguni-like cheese was performed for the first time. The taxonomic profiling of metagenomic reads revealed that Lactococcus species, such as Lc. lactis and Lc. cremoris prevailed in khuruud, bryndza, one sample of cottage cheese and khurunga. The latter one together with suluguni-like cheese microbiome was dominated by bacteria, affiliated to Lactobacillus helveticus (32-35%). In addition, a high proportion of sequences belonging to the genera Lactobacillus, Lactococcus and Streptococcus but not classified at the species level were found in the suluguni-like cheese. Lactobacillus delbrueckii, as well as Streptococcus thermophilus constituted the majority in another cottage cheese, kefir and ayran metagenomes. The microbiome of shubat, produced from camel's milk, was significantly distinctive, and Lentilactobacillus kefiri, Lactobacillus kefiranofaciens and Bifidobacterium mongoliense represented the dominant components (42, 7.4 and 5.6%, respectively). In total, 78 metagenome-assembled genomes with a completeness ≥ 50.2% and a contamination ≤ 8.5% were recovered: 61 genomes were assigned to the Enterococcaceae, Lactobacillaceae and Streptococcaceae families (the Lactobacillales order within Firmicutes), 4 to Bifidobacteriaceae (the Actinobacteriota phylum) and 2 to Acetobacteraceae (the Proteobacteria phylum). A metagenomic analysis revealed numerous genes, from 161 to 1301 in different products, encoding glycoside hydrolases and glycosyltransferases predicted to participate in lactose, alpha-glucans and peptidoglycan hydrolysis as well as exopolysaccharides synthesis. A large number of secondary metabolite biosynthetic gene clusters, such as lanthipeptides, unclassified bacteriocins, nonribosomal peptides and polyketide synthases were also detected. Finally, the genes involved in the synthesis of bioactive compounds like β-lactones, terpenes and furans, nontypical for fermented milk products, were also found. The metagenomes of kefir, ayran and shubat was shown to contain either no or a very low count of antibiotic resistance genes. Altogether, our results show that traditional indigenous fermented products are a promising source of novel probiotic bacteria with beneficial properties for medical and food industries.

Metabolic Evaluation of Lupin-Enriched Yogurt by Nuclear Magnetic Resonance Metabolomics.

Untargeted nuclear magnetic resonance (NMR) metabolomics was used to evaluate compositional changes during yogurt fermentation upon lupin enrichment compared to traditional conditions. Lupin significantly changed the sample metabolic profile and its time course dynamics, seemingly delaying microbial action. The levels of organic and amino acids were significantly altered, along with those of some sugars, nucleotides, and choline compounds. Lupin seemed to favor acetate and formate synthesis, compared to that of citrate and fumarate; a higher formate levels may suggest increased levels of Streptococcus thermophilus action, compared toLactobacillus bulgaricus. Lupin-yogurt was poorer in hippurate, lactose (and hence lactate), galactose, glucose-1-phosphate, and galactose-1-phosphate, containing higher orotate levels (possibly related to increased uridine derivatives), among other differences. Trigonelline was confirmed as a lupin marker, possibly together with glutamate and histidine. Other metabolite trajectories remained unchanged upon lupin addition, unveiling unaffected underlying processes. These results demonstrate the usefulness of untargeted NMR metabolomics to understand/develop new foodstuffs and their production processes, highlighting the identity of a variety of bioactive metabolites with importance for human health.

Ecological diversity and associated volatilome of typical mountain Caciotta cheese from Italy

Traditional products are particularly appreciated by consumers and among these products, cheese is a major contributor to the Italian mountainous area economics. In this study, shotgun metagenomics and volatilomics were used to understand the biotic and abiotic factors contributing to mountain Caciotta cheese typicity and diversity. Results showed that the origin of cheese played a significant role; however, curd cooking temperature, pH, salt concentration and water activity also had an impact. Viral communities exhibited higher biodiversity and discriminated cheese origins in terms of production farms. Among the most dominant bacteria, Streptococcus thermophilus showed higher intraspecific diversity and closer relationship to production farm when compared to Lactobacillus delbrueckii. However, despite a few cases in which the starter culture was phylogenetically separated from the most dominant strains sequenced in the cheese, starter cultures and dominant cheese strains clustered together suggesting substantial starter colonization in mountain Caciotta cheese. The Caciotta cheese volatilome contained prominent levels of alcohols and ketones, accompanied by lower proportions of terpenes. Volatile profile not only demonstrated a noticeable association with production farm but also significant differences in the relative abundances of enzymes connected to flavor development. Moreover, correlations of different non-homologous isofunctional enzymes highlighted specific contributions to the typical flavor of mountain Caciotta cheese. Overall, this study provides a deeper understanding of the factors shaping typical mountain Caciotta cheese, and the potential of metagenomics for characterizing and potentially authenticating food products.

Exopolysaccharides from Enterococcus faecium and Streptococcus thermophilus: Bioactivities, gut microbiome effects, and fermented milk rheology

Exopolysaccharides (EPSs) are carbohydrate polymers that can be produced from probiotic bacteria. This study characterized the EPSs from Enterococcus faecium (EPS-LB13) and Streptococcus thermophilus (EPS-MLB10) and evaluated their biological and technological potential. The EPSs had high molecular weight and different monosaccharide compositions. The EPSs exhibited various biological activities at 250 mg/L, such as scavenging free radicals (10 % to 88.8 %), enhancing antioxidant capacity (714 to 2848 µg/mL), inhibiting pathogens (53 % to 74 %), and suppressing enzymes and cancer cells (2 % to 83 %), etc. The EPSs supported the growth of beneficial gut bacteria from Proteobacteria, Bacteroidetes, Firmicutes, and Acinetobacter in fecal fermentation with total Short-chain fatty acids production from 5548 to 6023 PPM. Moreover, the EPSs reduced the gelation time of fermented skimmed bovine milk by more than half. These results suggest that the EPSs from LB13 and MLB10 have promising applications in the dairy and pharmaceutical industries.

Safety assessment, whole genome sequence, and metabolome analysis of Streptococcus thermophilus CICC 20372 for bone cement fermentation.

Bone is a kind of meat processing by-product with high nutritional value but low in calorie, which is a typical food in China and parts of East Asian countries. Microbial fermentation by lactic acid bacteria showed remarkable advantages to increase the absorption of nutrients from bone cement by human body. Streptococcus thermophilus CICC 20372 is proven to be a good starter for bone cement fermentation. No genes encoding virulence traits or virulence factors were found in the genome of S. thermophilus CICC 20372 by a thorough genomic analysis. Its notable absence of antibiotic resistance further solidifies the safety. Furthermore, the genomic analysis identified four types of gene clusters responsible for the synthesis of antimicrobial metabolites. A comparative metabolomic analysis was performed by cultivating the strain in bone cement at 37°C for 72h, with the culture in de Man, Rogosa, and Sharpe (MRS) medium as control. Metabolome analysis results highlighted the upregulation of pathways involved in 2-oxocarboxylic acid metabolism, ATP-binding cassette (ABC) transporters, amino acid synthesis, and nucleotide metabolism during bone cement fermentation. S. thermophilus CICC 20372 produces several metabolites with health-promoting function during bone cement fermentation, including indole-3-lactic acid, which is demonstrated ameliorative effects on intestinal inflammation, tumor growth, and gut dysbiosis. In addition, lots of nucleotide and organic acids were accumulated at higher levels, which enriched the fermented bone cement with a variety of nutrients. Collectively, these features endow S. thermophilus CICC 20372 a great potential strain for bone food processing.

Impact of ultrasonicated Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Lactiplantibacillus plantarum AF1 on the safety and bioactive properties of stirred yoghurt during storage

In this study, the effects of ultrasonicated Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus and Lactiplantibacillus plantarum AF1 (100 W, 30 kHz, 3 min) on the safety and bioactive properties of stirred yoghurt during storage (4 °C for 21 days) were investigated. The results showed that sonicated cultures were more effective in reducing pathogens than untreated ones. The highest antioxidant activity (DPPH and ABTS), α-glucosidase and α-amylase inhibition capacity were found in yoghurt containing sonicated probiotic + sonicated yoghurt starter cultures (P + Y + ). The highest amount of peptides (12.4 mg/g) was found in P + Y + yoghurts at the end of the storage time. There were not significant differences between the exopolysaccharide content of P + Y+ (17.30 mg/L) and P + Y- (17.20 mg/L) yoghurts, although it was significantly (P ≤ 0.05) higher than the other samples. The use of ultrasonicated cultures could enhance the safety of stirred yoghurt and improve its functional and bioactive properties.

Soybean hull polysaccharides affect the physicochemical properties and lactic acid bacteria proliferation in plant‐based yogurt

AbstractAs a by‐product of soybean processing, soybean hulls contain soybean hull polysaccharides (SHPS). This study aims to develop a plant‐based yogurt with SHPS addition and assess the consequences of SHPS on the physicochemical properties and growth of lactic acid bacteria (LAB) in yogurts. The study investigated the water holding capacity (WHC), microstructure, rheological properties, texture, pH, organoleptic attributes, volatile compounds, flavor profile, and LAB population. The findings reveal that the addition of SHPS significantly impacted these properties. SHPS improved the physicochemical properties, increased the level of flavor compounds, and improved the organoleptic properties of yogurt. Yogurt with 0.6% SHPS demonstrated superior WHC, texture, rheological properties, and the highest organoleptic evaluation scores. However, when SHPS additions exceeded 0.6%, WHC, texture, and rheological properties of the yogurts decreased. Furthermore, SHPS‐added yogurts contained more LAB compared to yogurt without SHPS. LAB grew better in media with SHPS than in media without glucose. Streptococcus thermophilus grew best among the LAB strains. This study highlights the potential of SHPS in yogurt production and its promising applications in fermented food products.

Investigating the impact of exopolysaccharides on yogurt network mechanics and syneresis through quantitative microstructural analysis

Exopolysaccharides produced by lactic acid bacteria are widely used to improve the sensory properties of yogurt. The relation between the physical properties of the microbial exopolysaccharides and the structural and rheological properties of the yogurt are incompletely understood to date. To address this knowledge gap, we studied how two distinct exopolysaccharides influence the microstructure, rheological properties, and syneresis of yogurt. The effect of a negatively charged, capsular exopolysaccharide produced by Streptococcus thermophilus and a neutral, non-capsular exopolysaccharide produced by Lactococcus lactis were investigated. Using quantitative microstructural analysis, we examined yogurt samples prepared with either the capsular or the non-capsular exopolysaccharide, and with mixtures of the two. Confocal laser scanning microscopy and stimulated emission depletion microscopy were employed to visualize the microstructures, revealing differences in pore size distribution, protein domain size, and casein interconnectivity that were not apparent through visual inspection alone. Additionally, variations in rheological properties were observed among the different yogurt types. In the yogurt fermented with both bacterial strains, we observed a combined impact of the two exopolysaccharide types on relevant microstructural and rheological properties. The negatively charged capsular exopolysaccharide enhanced casein interconnectivity and gel stiffness, while the neutral non-capsular exopolysaccharide led to thicker protein domains, an abundance of small pores, and a lower loss tangent. These factors collectively hindered syneresis, resulting in improved structural integrity. Our study not only provides valuable insights into the influence of different exopolysaccharides on yogurt properties, but also presents the first demonstration and quantification of the effect of multiple types of exopolysaccharides on casein interconnectivity. These findings offer guidance for the production of yogurts with customized microstructure, rheological properties, and resistance to syneresis.

The synbiotic combination of probiotics and inulin improves NAFLD though modulating gut microbiota

Prebiotics can promote the growth of probiotics, cocombine of these is called synbiotics, and synbiotics is powerful regulators of gut microbiota. Intestinal microbiota plays an important role in nonalcoholic fatty liver disease (NAFLD), so synbiotics could be a therapeutic alternative. This study aims to investigate the effect of synbiotics combination of probiotics (Streptococcus Bifidobacterium and Streptococcus thermophilus) and prebiotics (Inulin) in vivo model of early NAFLD using yogurt as carrier. The results demonstrate that the yogurt with synbiotics combination group (HS) improves the biochemical indicators related to total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL-C), high-density lipoprotein cholesterol (HDL-C), and insulin resistance (IR) in mice (P< .01). HS improves the development of lipid metabolism and inflammation by activating the AMPK and NFκB signaling pathway. In addition, HS restores the intestinal barrier dysfunction and inflammation caused by a high-fat diet. The 16S rRNA demonstrates that the gut microbiota composition of mice treated with HS is significantly altered specifically, the Firmicutes/Bacteroidetes ratio is significantly lower than in HFD-fed mice (P< .01). Our findings suggest the applicability of HS in preventing obesity-related NAFLD via its antioxidant, anti-inflammatory, and improved lipid metabolism by the gut-liver axis and provide a solid theoretical foundation for developing prebiotics for the prevention of NAFLD.

Utilization of pomegranate and black grape seed by-products in yogurt production: Effects on phenolic compounds and antioxidant activity.

The present study investigated the potential utilization of pomegranate and black grape seed by-products of the food industry in yogurt production. Specifically, we examined the effect of polyphenols on antioxidants in yogurts produced using two different starter cultures: classical yogurt culture (Lactobacillus delbrueckii subsp. bulgaricus + Streptococcus thermophilus) and yogurt culture supplemented with L. casei. Various parameters, including pH, acidity, viscosity, fat content, protein content, dry matter content, color, microbiological properties, and sensory attributes, were analyzed in the yogurt products. The present findings indicate that incorporating pomegranate and grape seed powder and using different starter cultures significantly affected the yogurt's phenolic content and antioxidant activity. Furthermore, we observed decreased phenolic content and antioxidant activity during the 21-day storage period. Interestingly, yogurts produced with pomegranate seed powder and L. casei culture exhibited higher antioxidant activity than the other samples. Importantly, none of the yogurts containing pomegranate and grape seed powders had microbial counts below 107 cfu/g for L. delbrueckii subsp. bulgaricus, S. thermophilus, and L. casei, indicating no adverse effects on probiotic properties. Sensory evaluation revealed that the yogurt product prepared with grape seed powder and a combination of yogurt culture (L. delbrueckii subsp. bulgaricus + Streptococcus thermophilus) and L. casei was particularly well-received. In conclusion, the functional properties of grape seed powder and pomegranate seed powder make them suitable natural ingredients for enhancing the antioxidant activity of yogurt. The study highlights the potential of utilizing these by-products to develop yogurt products with added health benefits.