Microbial diversity and health-promoting properties of the traditional Bulgarian yogurt

Carbonate and silicate dissolving bacteria isolated from home-made yogurt samples

In the current study, twenty-eight bacterial strains were isolated from home-made yogurt samples from Ağrı Province, Turkey. The bacterial strains were identified by conventional and molecular techniques. Among the twenty- eight isolates, seventeen isolates were identified according to the 16 S rDNA region and determined to belong to five different genus including Sphingomonas (8 isolates), Burkholderia (5 isolates), Lactobacillus (2 isolates), Lactococcus (1 isolate), Staphylococcus (1 isolate). In this study, the presence of Burkholderia in home-made yogurt samples were reported for the first time, whereas Sphingomonas was detected for the second time. We also investigated the carbonate (CaCO3 and MgCO3) and silicate (‎CaSiO3 and MgSiO3) dissolving potential of seventeen bacterial isolates. Among these seventeen bacterial isolates, fifteen bacterial isolates have CaCO3-dissolving and 10 bacterial isolates have MgCO3-dissolving potential. The silicates dissolution ability was relatively less than that of carbonates dissolving. We observed that six bacterial isolates have CaSiO3 and only two bacterial isolates have MgSiO3 dissolution abilities. In conclusion, this work clearly shows the diversity of bacteria existing in fermented cow milk samples in Ağrı Province, Turkey, which could be considered as valuable sources for lactic acid bacteria (LAB) isolation and further probiotic potential.

Bioactive Compounds Produced by the Accompanying Microflora in Bulgarian Yoghurt

Bulgarian yoghurt is associated with health benefits and longevity of consumers. The specific microflora producing bioactive metabolites is responsible for this effect. The present study examines the biodiversity in four homemade yoghurts from regions containing endemic microflora. Metagenome sequencing indicated Lactobacillus delbrueckii subsp. bulgaricus and Streptococcus thermophilus were predominant in all samples. In addition, yoghurts contained accompanying lactic acid bacteria (LAB) including Lacticaseibacillus paracasei, Lb. helveticus, Limosilactobacillus fermentum, Lb. rhamnosus, Lactococcus lactis, Pediococcus acidilactici, Leuconostoc mesenteroides, and Leuc. pseudomesenteroides. A negligible amount of pollutant strains was found. Twenty-four LAB strains were isolated from the yoghurts and identified. Lb. delbrueckii subsp. bulgaricus strains were genotyped by randomly amplified polymorphic DNA–PCR (RAPD), multi-locus sequence typing (MLST), and pulse field gel electrophoresis (PFGE), which demonstrated their uniqueness and non-commercial origin. To estimate the bioactive metabolites produced by the accompanying microflora, yoghurts fermented by single LAB strains were analyzed using liquid chromatography and mass spectrometry (LC-MS). The fermented samples contained large amounts of free essential amino acids (arginine, citrulline, tryptophan, lysine, and histidine), the neuroprotector indole-3-propionic acid (IPA), and significant quantities of the cyclic antimicrobial peptides cyclo(phenylalanyl-prolyl) and cyclo(leucyloprolyl). The disclosure of these special qualities draws attention to the accompanying microflora as a source of potential probiotic strains that can fortify the yoghurts’ content with bioactive compounds.

Lactic Acid Fermentation of Cereals and Pseudocereals: Ancient Nutritional Biotechnologies with Modern Applications

Grains are a substantial source of macronutrients and energy for humans. Lactic acid (LA) fermentation is the oldest and most popular way to improve the functionality, nutritional value, taste, appearance and safety of cereal foods and reduce the energy required for cooking. This literature review discusses lactic acid fermentation of the most commonly used cereals and pseudocereals by examination of the microbiological and biochemical fundamentals of the process. The study provides a critical overview of the indispensable participation of lactic acid bacteria (LAB) in the production of many traditional, ethnic, ancient and modern fermented cereals and beverages, as the analysed literature covers 40 years. The results reveal that the functional aspects of LAB fermented foods are due to significant molecular changes in macronutrients during LA fermentation. Through the action of a vast microbial enzymatic pool, LAB form a broad spectrum of volatile compounds, bioactive peptides and oligosaccharides with prebiotic potential. Modern applications of this ancient bioprocess include the industrial production of probiotic sourdough, fortified pasta, cereal beverages and "boutique" pseudocereal bread. These goods are very promising in broadening the daily menu of consumers with special nutritional needs.

The impact of raw fermented milk products on perceived health and mood among Dutch adults

Purpose

The purpose of this paper was to evaluate health conditions prior to and at least two months after the start of consuming raw fermented milk (RFM) products.

Design/methodology/approach

One-Item health score, 1-item immunity score, immune status (ISQ), mood, bowel and skin conditions were rated for the period prior and post switching to RFM products. A linear mixed model was used to evaluate the post to prior RFM health and mood scores, taking into account gender, location of living and health group. Data from 390 participants (mean age of 54 years old) were included for the analysis, of which 277 (45 per cent) were allocated to the poor health group. Participants were allocated to the poor health group if they reported being immune depressed or suffering from a chronic disease prior to RFM; otherwise, they were allocated to the normal health group.

Findings

The highest intake of RFM was from RF kefir. Post RFM, people consumed around 1 glass (200 ml) of RF kefir per day. After switching to RFM, significant improvements on health and mood scores were reported. The strongest improvements after switching to RFM consumption were seen in subjects from the poor health group. With the exception of skin score, all measured health items significantly improved (p < 0.001). Health, immunity, bowel and mood scores increased with around 20 per cent in the poor health group and around 8 per cent in the normal health group. Women had more health complaints prior to RFM and had stronger health improvement post RFM compared to men. Bowel and mood scores were overall lower in women than in men. Living location had no significant impact on RFM-related health changes. This consumer survey suggests that positive health and mood changes are associated with the consumption of RFM products.

Originality/value

The consumption of RFM products improved the self-reported health status of adults. Immune-depressed people or people suffering from a chronic disease prior to RFM reported the strongest impact on their health, immunity, bowel and mood scores post switching RFM consumption compared to people with a normal health.