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- Author or Editor: Á. Jozwiak x
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Summary
A reversed-phase high-performance liquid chromatography diode array detector (HPLC-DAD) method was developed for the separation of triterpene acids and their determination in crude extracts of Potentilla species. Symmetry octadecylsilyl silica (ODS) column with acetonitrile and water with phosphoric acid (pH = 2.5) as the mobile phase was used in the described HPLC system. The column temperature was at 20 °C, the flow rate was 0.8 mL/min. The detection wavelength was 210 nm. For quantitative purposes, the linear dependencies of analyte concentration and peak surface area were obtained with regression coefficient values 0.9983 < r 2 < 0.9995. For euscaphic acid, calibration was performed in the range of 0.07–0.525; 0.7–2.1 mg/mL, for pomolic acid in the range of 0.019–0.171; 0.209–0.665 mg/mL, for ursolic acid in the range of 0.2–1.375–3.3 mg/mL. The observed recovery of triterpene acids was from 95.3% to 103.1%. The observed values of RSD were well within the generally acceptable limit of no more than 5%. This method was successfully applied to quantify pomolic acid (PA), ursolic acid (UA) and the sum of euscaphic (EA) and tormentic acids (TA) (expressed as euscaphic acid) in roots and rhizomes of 15 various Potentilla species and 2 subspecies (i.e., P. atrosanguinea, P. recta).
The aim of this study was to develop simple, rapid and reliable methods for the selective determination of Bifidus essensis from ACTIVIA (Danone) yogurts. The methods are based on a modified MRS medium (B-broth), which does not contain inhibitory additives. The sugar source of the medium is maltose, which is metabolized by the bifidobacteria applied in the probiotic products, and not by the normal microflora of yogurt ( Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus ). The redox potential of the medium was reduced with cysteine-HCl. Due to its reduced redox potential, the new bouillon is suitable for aerobic cultivation of bifidobacteria, while in agar form it needs anaerobic incubation. In bouillon form (MPN method) the incubation time is only 2 days compared to the 5-day requirement of the classical anaerobic plate counting methods. The B-broth in diluted form was successfully used in a RABIT (Don Whitley) equipment for selective impedimetric determination of bifidobacteria in Danone yogurts. The exact detection time of the Bifidobacterium counts in a good quality probiotic yogurt, containing bifidobacteria at a concentration of 10 7 to 10 8 CFU ml −1 is not more than 10 to 12 h (in contrast to the 5 days of classical anaerobic plate counting methods).
Abstract
Tendencies of foodborne outbreaks show that the number of illnesses caused by Campylobacter spp. has been increasing recently in the European Union and in Hungary as well. However, the epidemiological statuses of Member States are diverse. There are several aspects to be investigated by competent authorities before the introduction of interventions. Methods supporting food safety decision making range from quick and easy techniques to complex, resource consuming approaches. The aim of the present study was the implementation of an evaluation and ranking system for a risk and its causes occurring in the broiler production chain. Data and information available in scientific literature were converted to a structured easy-to-use evaluation that supports decision making and helps structured data processing.
