Measuring and comparing the water activity and salt content in Parenica cheeses made by traditional and industrial technology.

BACKGROUND: Slovenská Parenica is one of the most traditional and ever-popular sheep´s milk cheese specialities. This cheese has been registered as a geographical indication (PGI) in the EU. Parenica cheese is produced also from cow´s milk, but without the trade name "Slovenská/Slovak". OBJECTIVE: The aim of our research was was statistical reporting and results visualization of water activity analysis and salt content in cow´s milk Parenica cheeses from 8 small and medium-sized Slovak dairy producers. MATERIAL AND METHOD: A total of 320 samples of smoked and non-smoked Parenica cheeses made from cow´s milk using traditional and industrial technology were examined during the 10-month period. Each cheese was analysed immediately after sampling (A) and subsequently after 7 days of storing at 4°C (B). The salt content was measured on the Chloride analyser M 926 and the water activity on the Fast-Lab meter. Due to the hierarchical design of the experiment, the linear mixed models via the R statistical environment to compare the differences in the water activity and salt content were used. RESULTS: Statistical reporting and visualization of water activity measurements showed significant differences between samples A and B ( p = 0.0129) and between kinds of Parenica cheese ( p = 0.0196). The value of water activity ranged from 0.908 to 0.975 (A) with the increasing trend after storing in both kinds of Parenica cheese. The impact of dairy producer type was not significant. The higher content of NaCl was found in fresh Parenica cheese from small farms (nonsmoked: 2.51 ±1.12 g/100 g, smoked: 1.97 ±0.89 g/100 g). The average salt content in cheeses from industrial dairies was 1.65 ±0.34 g/100 g (non-smoked) and 1.96 ±0.43 g/100 g (smoked). Results showed lower variability of salt content in cheeses from industrial dairies. CONCLUSIONS: It can be concluded that especially the small producers can have probably problem in noncompliance with the technological processes, non-implementation of standardized procedures and underestimation of hygiene regulations.

The Impact of Different Factors on the Quality and Volatile Organic Compounds Profile in "Bryndza" Cheese.

The aim of this study was to evaluate the influence of different factors on the basic physicochemical and microbiological parameters, as well as volatile organic compounds of traditionally (farm) and industrially produced "bryndza" cheese. The samples were obtained from eight producers in different areas of Slovakia during the ewe's milk production season, from May to September. The physicochemical parameters set by the legislation were monitored by reference methods. The "bryndza" cheese microbiota was determined by using the plate cultivation method. There was analysis of volatile organic compounds carried out by electronic nose, as well as gas chromatography mass spectrometry. Seasonality and production technology (traditional and industrial ones) are the main factors that affect the standard quality of "bryndza" cheese. Lactic acid bacteria were dominated from bacterial microbiota, mostly presumptive lactococci, followed presumptive lactobacilli and enterococci. The numbers of coliform bacteria were higher in traditionally produced "bryndza" cheese than in industrially produced "bryndza" cheese. The presence of Dipodascus geotrichum was detected in all samples. There were key volatile organic compounds such as ethyl acetate, isoamyl acetate, 2-butanone, hexanoic acid, D-limonene, and 2,3-butanedione. The statistically significant differences were found among "bryndza" cheese samples and these differences were connected with the type of milk and dairies.

Production of γ-aminobutyric acid by microorganisms from different food sources.

BACKGROUND: γ-Aminobutyric acid (GABA) is a potentially bioactive component of foods and pharmaceuticals. The aim of this study was screen lactic acid bacteria belonging to the Czech Collection of Microorganisms, and microorganisms (yeast and bacteria) from 10 different food sources for GABA production by fermentation in broth or plant and animal products. RESULTS: Under an aerobic atmosphere, very low selectivity of GABA production (from 0.8% to 1.3%) was obtained using yeast and filamentous fungi, while higher selectivity (from 6.5% to 21.0%) was obtained with bacteria. The use of anaerobic conditions, combined with the addition of coenzyme (pyridoxal-5-phosphate) and salts (CaCl2 , NaCl), led to the detection of a low concentration of GABA precursor. Simultaneously, using an optimal temperature of 33 °C, a pH of 6.5 and bacteria from banana (Pseudomonadaceae and Enterobacteriaceae families), surprisingly, a high selectivity of GABA was obtained. A positive impact of fenugreek sprouts on the proteolytic process and GABA production from plant material as a source of GABA precursor was identified. CONCLUSIONS: Lactic acid bacteria for the production of new plant and animal GABA-rich products from different natural sources containing GABA precursor can be used.