Dataset Information

Different Ultrasound Exposure Times Influence the Physicochemical and Microbial Quality Properties in Probiotic Goat Milk Yogurt.

ABSTRACT: Despite goat milk having health benefits over cow milk, goat milk yogurt (GY) presents low consistency and viscosity, which reduces its overall acceptability by the consumer. Thus, new innovative methods can be an alternative to improve the quality of GY. Hence, this study aimed to investigate the effect of ultrasound (US) treatment with different sonication times on quality parameters of probiotic GY during refrigerated storage. US treatment was conducted at 20 KHz for 3, 6, and 9 min in yogurt. Lactobacillus bulgaricus and Lactobacillus acidophilus LA-5 were sensitive to US treatment, presenting a decrease in the yogurts stocked. This loss of viability led to reduced post-acidification due to smaller lactose metabolization in yogurt samples submitted to the US. Among tested treatments, the application of 6 min enhanced the apparent viscosity and consistency index of GY yogurts. In addition, this time also reduced tyramine and total biogenic amine (BAs) content. These findings suggest that 6 min of sonication is a promising way to improve the rheological properties and reduce the acidity and BAs content in GY. Further studies should be performed to optimize the US setting conditions to preserve the probiotic culture viability in yogurts.

SUBMITTER: Delgado K

PROVIDER: S-EPMC7587201 | biostudies-literature | 2020 Oct

REPOSITORIES: biostudies-literature

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Different Ultrasound Exposure Times Influence the Physicochemical and Microbial Quality Properties in Probiotic Goat Milk Yogurt.

Delgado Karina K Vieira Carla C Dammak Ilyes I Frasão Beatriz B Brígida Ana A Costa Marion M Conte-Junior Carlos C

Molecules (Basel, Switzerland) 20201012 20

Despite goat milk having health benefits over cow milk, goat milk yogurt (GY) presents low consistency and viscosity, which reduces its overall acceptability by the consumer. Thus, new innovative methods can be an alternative to improve the quality of GY. Hence, this study aimed to investigate the effect of ultrasound (US) treatment with different sonication times on quality parameters of probiotic GY during refrigerated storage. US treatment was conducted at 20 KHz for 3, 6, and 9 min in yogurt ...[more]

PMID: 33053748

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Project description:Probiotics are considered effective microbial dietary supplements that provide beneficial effects to consumers, usually by restoring or improving gut microflora. Goat milk is one of the rich sources of probiotics as well as nutrients. Therefore, the primary aim of this research was to isolate and evaluate the potential of novel indigenous probiotic strains present in goat milk. Six different raw goat milk samples were collected from different areas of Multan, Pakistan. For bacterial characterization, samples were cultured and isolated on MRS agar plates for different morphological and biochemical tests. The probiotic potential of the six isolates, all of which were gram positive (G1, G2, G3, G4, G5, and G6) and five of which were catalase negative (all except G1), were assessed via a milk coagulation assay and antimicrobial activity, pH tolerance, phenol tolerance, and sodium chloride (NaCl) tolerance tests, which revealed that all the isolates coagulated in milk and showed protease and lipase activity, except G3. All six isolates showed tolerance against 0.2% phenol and 2-4% NaCl and were able to survive in both alkaline and acidic conditions. Only five isolates showed antimicrobial activity against indicator strain Aspergillus niger strain STA9, validating their probiotic nature. The most potent bile-tolerant and bacteriocin-producing isolate, G1, also showed γ-hemolytic activity and resistance to penicillin but showed susceptibility to other antibiotics. The lactic acid-producing (0.60% titratable acidity) G1 isolate was identified as a novel strain of Mammaliicoccus sciuri based on 16S rDNA sequencing. The above findings suggest that the potent M. sciuri GMN01 strain can serve as a potential probiotic strain. A potent probiotic strain isolated from raw goat milk could be utilized as a dietary supplement, and goat milk could become an alternative to other sources of milk, particularly cow milk. However, safety aspects of this strain require further investigation because the present safety tests are insufficient to conclude that the GMN01 isolate is safe.

Project description:In the current study, we screened 46 isolates of lactic acid bacteria (LAB) derived from goat milk for bacteriocin producers that can inhibit common foodborne pathogens (Staphylococcus aureus, Listeria monocytogenes, and Bacillus cereus). The following three strains that showed antimicrobial activity against all indicators were identified: Enterococcus faecalis DH9003 and DH9012, and Lactococcus lactis DH9011. Their antimicrobial products exhibited typical bacteriocin characteristics, such as heat stability and proteinase nature. The bacteriostatic activity of concentrated bacteriocins produced by these LAB was observed at low concentrations (half-minimum inhibitory concentration [MIC50] and 4MIC50), whereas complete inhibition activity against Listeria monocytogenes was detected at high concentrations (16MIC50) of the two Enterococcus faecalis strains (DH9003 and DH9012). Furthermore, the probiotic potentials of the three strains were investigated and described. The results revealed that none of the strains had hemolytic activity, whereas all: were sensitive to ampicillin (50 mg/mL) and streptomycin sulfate (100 mg/mL); were resistant to bile, artificial simulated intestinal tract, and gastric juice at different pH levels (2.5, 3.0, 3.5); and had β-galactosidase activity. Furthermore, all strains exhibited an auto-aggregating phenotype, with self-aggregation ranging from 30% to 55%. DH9003 and DH9012 co-aggregated well with Listeria monocytogenes and Escherichia coli (52.6% and 63.2%, 68.5% and 57.6%, respectively), whereas DH9011 co-aggregated poorly with Listeria monocytogenes (15.6%) and did not co-aggregate with Escherichia coli. Furthermore, our results showed that all three isolates exhibited strong antibacterial activity, tolerance to bile and simulated gastrointestinal environments, adhesion capability, and safety. Finally, DH9003 was selected and used for gavage in rats. By observing the pathological characteristics of rat intestinal and liver tissue sections, DH9003 showed no harmful effects on the intestine and liver of rats, but rather resulted in a denser and longer intestinal mucosa, as well as improving the intestinal mucosa of rats. Considering their substantial prospective applications, we concluded that these three isolates are potential probiotic candidates.

Project description:Introduction: Following a school milk feeding program in Southwest Uganda, we initiated a probiotic yogurt school feeding program in the same region in 2018. In order to investigate the potential health benefits from probiotic yogurt we conducted an observational study, where we compared the effect of the consumption of locally produced probiotic yogurt containing Lactobacillus rhamnosus yoba 2012 to milk in pre-primary schoolchildren from different schools on the occurrence of respiratory tract infections (common cold) and skin infections (e.g., tinea capitis). Method: A comparative interrupted time series over a period of 3 weeks of baseline followed by 9 weeks of 100 ml of probiotic yogurt or milk consumption for 5 days per week. In total 584 children attending five different schools were followed during consumption of probiotic yogurt and 532 children attending five other schools during consumption of milk. Incidences of respiratory tract infection symptoms and skin infection symptoms, changes in anthropometric indicators and absenteeism were recorded. Results: Over the course of the study period the incidence rate for common cold symptoms decreased faster in the yogurt group than in the milk group (p = 0.09) resulting in a final RR of 0.85 (95% CI: 0.5-1.4) at the end of the observational period. The incidence rate of skin infection related symptoms also reduced faster in the yogurt group compared to the milk group (p < 0.0001) resulting in a relative risk factor (RR) of 0.6 (CI: 0.4-0.9) at the end of the observational period. Anthropometric indicators and level of absenteeism did not show significant differences between yogurt and milk. Conclusion: Notwithstanding the observed positive trend and effect of probiotic yogurt on the incidences of common cold and skin infections, respectively, we consider the results of this comparative interrupted time series inconclusive due to differences in the recorded health parameters between the probiotic yogurt and milk control groups at base line, and fluctuations over the course of the intervention period. An improved study design, with more uniform study groups, a longer intervention period and a third control group without yogurt or milk is required to draw definitive conclusions.

Dataset Information

Different Ultrasound Exposure Times Influence the Physicochemical and Microbial Quality Properties in Probiotic Goat Milk Yogurt.

Publications

Different Ultrasound Exposure Times Influence the Physicochemical and Microbial Quality Properties in Probiotic Goat Milk Yogurt.

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