Pályázati anyagok

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https://hdl.handle.net/2437/200818

Böngészés

Pályázati anyagok Szerző szerinti böngészés "Ajtony, Zsolt"

Megjelenítve 1 - 2 (Összesen 2)
  • Nincs kép
    TételKorlátozottan hozzáférhető
    Exploring the rosmarinic acid profile of dark chocolate fortified with freeze-dried lemon balm extract using conventional and non-conventional extraction techniques
    Sik, Beatrix; Hanczné Lakatos, Erika; Kapcsándi, Viktória; Székelyhidi, Rita; Ajtony, Zsolt; PhD hallgató; egyetemi oktató, kutató
    The present study evaluated the feasibility of the fortification of dark chocolate with a freeze-dried lemon balm extract rich in rosmarinic acid (RA). Given the food matrix used, it was necessary to develop an analytical and extraction method for RA determination in fortified chocolate. A simple and efficient reversed-phase high-performance liquid chromatography method (RP-HPLC) has been developed for the estimation of RA in dark chocolate. The validity of the method was demonstrated by evaluating the system suitability, linearity, precision, accuracy, the limit of detection, and limit of quantification. The extraction of RA from chocolate was optimized using maceration with shaking (MACS) and microwave-assisted extraction (MAE). The experimental conditions, namely solvent type and extraction time, were optimized using the one-factor-at-a-time methodology. Under the optimized conditions, the proposed method showed good recovery within 95% and acceptable reproducibility with intra- and inter-day relative standard deviations of <2.3%. The method was linear from 5 to 800 mu g/mL with a determination coefficient of 1.000. Moreover, the functional chocolate showed a homogeneous active ingredient distribution and retained its RA amount since no significant difference was observed during storage. Overall, the present method was successfully applied to determine RA content in fortified chocolate.
  • Nincs kép
    TételKorlátozottan hozzáférhető
    Investigation of the long-term stability of various tinctures belonging to the lamiaceae family by HPLC and spectrophotometry method
    Sik, Beatrix; Hanczné Lakatos, Erika; Kapcsándi, Viktória; Székelyhidi, Rita; Ajtony, Zsolt; PhD hallgató; egyetemi oktató, kutató
    The aim of the current study was to analyze the stability of rosmarinic acid in ethanolic tinctures of lemon balm (Melissa officinalis L.), oregano (Origanum vulgare L.), peppermint (Mentha x piperita), rosemary (Rosmarinus officinalis L.), sage (Salvia officinalis L.), and thyme (Thymus vulgaris L.). High-performance liquid chromatography with diode-array detection (HPLC-DAD) was employed to monitor the concentration of the marker compound over a six month period. Furthermore, the tinctures were also evaluated for caffeic acid, total phenolic content, and 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity. We observed that the concentration of rosmarinic acid in tincture stored in closed amber glasses at ambient temperature decreased significantly during 6-month storage. Furthermore, our study squarely confirms the fact that a part of rosmarinic acid is converted to caffeic acid. The tested tinctures can be listed in the following order according to the greatest stability of the marker compound: rosemary > peppermint > oregano > lemon balm > thyme > sage. The results of the study indicated a linear relationship between DPPH values and total phenolic (R-2 = 0.92) or rosmarinic acid (R-2 = 0.85) contents.