No abstract

In Kazakhstan where Bactrian camel, dromedary camel and their hybrids are cohabiting within same farms, the consumption of camel milk is very popular because its medicinal and dietary properties. This milk is consumed under fermented form, called shubat. Shubat is still very often made on a small scale in the steppe with a fermentation step driven by wild bacteria. Camel milk and shubat were sampled from 4 regions with high number of camel population. As the whole, 26 samples were obtained from 13 selected farms representing the variability of the farming system. Isolated LAB strains were identified by method of a polymorphism determination of 16S ribosome DNA. PCR with using two different pairs of amorces (338f/518r; W001/23S1) was done. Majority of microflora were cocci in a both milk products. Yeast biodiversity in shubat was studied by using denaturing gradient gel electrophoresis (DGGE). Target DNA bands were identified according to the reference species scoring. Comigrating bands present in the DGGE profiles were resolved by species-specific PCR. The dominant yeasts in both products included Kazakhstania unispora, Saccharomyces cerevisiae and Kluyveromyces marxianus. Frequently isolated yeast species were Dekkera bruxellensis and more rarely Galactomyces geotrichum. The results of microflora identification in these products provide a theoretical foundation for developing starter cultures.

Milk fat adulteration is a common issue in Central Asia. To assess the current situation in the commercial milk market, 17 milk samples were checked for fatty acid (FA) and sterol profiles to detect potential adulteration using multivariate analysis. Analysis of FA and sterols was performed using gas chromatography with flame ionization detection and gas chromatography with mass-spectrometric detection, respectively. Cluster analysis of FA profiles revealed 3 types of milk samples: (1) samples containing a higher proportion of short-chain FA, (2) samples containing a higher proportion of long-chain FA, and (3) samples with significant amounts of C18 FA. Analysis of sterols showed that samples included (1) milk fat containing 100% cholesterol, sometimes with traces of phytosterols, (2) milk fat with high proportions of β-sitosterol and campesterol, and (3) milk fat containing high proportions of brassicasterol. We found significant relationships between FA profiles and sterol profiles. The profiles were compared with vegetable oil patterns reported in the literature. More than 50% of the samples appeared to be counterfeited. We conclude that identification of adulteration in milk can be based solely on determination of sterol patterns.

Shubat and Koumiss are traditional fermented products widely consumed in Kazakhstan and Central Asia. Microflora of those fermented products is composed of bacteria and yeasts, which could have deep impacts on beverages quality. Although, the known presence of yeast in such fermented foods, few studies on yeast microflora of Shubat and Koumiss were available. The aim of the study was to identify the main indigenous yeasts in these traditional beverages and additionally, the differences between these 2 types of fermented products. Five samples of fresh and fermented camel and mare's milk from tank were collected in 5 different farms, located in South of Kazakhstan. Farms were selected because of their importance of production of fermented milk at the regional level and the reputation of these products among the consumers. Yeast biodiversity in Shubat and Koumiss was studied using denaturing gradient gel electrophoresis (DGGE). Target DNA bands were identified according to the reference species ladder, constructed in this study. Co-migrating bands present in the DGGE profiles were resolved by species-specific PCR. Galactomyces geotrichum, Kluyveromyces marxianus, Kazachstania unispora, Saccharomyces cerevisiae, Dekkera anomala, Dekkera bruxellensis yeast were identified. Some yeasts were not identified by used primers. In all samples of Shubat and Koumiss the dominant yeast species were Kazakhstania unispora, Kluyveromyces marxianu. Other species were not present in all samples. (Résumé d'auteur