Browsing by Author "Radoeva R."

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    CONVECTIONAL EXTRACTION OF PHENOLIC COMPOUNDS FROM RED FRUITS – CHOKEBERRY (ARONIA) AND ELDERBERRY
    (2023-01-01) Enchev B.; Karsheva M.; Radoeva R.
    The aim of this study was to compare the quality of phenolic content and antioxidant capacity of Chokkeberry (Aronia) and Elderberry plants. Characterisation of phenolic compounds was carried out by Folin-Ciocalteau method. Antioxidant activity of Chokeberry (Aronia) and Elderberry products were determined using 2,2-diphenyl-2-picrylhydrazyl (DPPH). All extraction runs were carried out at constant extractive parameters chosen previously - temperature, sample particle size, extraction manner. All analyses were performed spectrophotometrically. This study focuses on the convectional extraction - particularly conventional solid-liquid extraction (conducted via magnetic stirrer) of pre-dried Chokeberry and Elderberry. An investigation of total polyphenol contents (TPC) and total antioxidant capacity (TAC) were done. Extraction takes place at a pre-selected duration of 100 minutes. The extraction was examined with 5 solvents: aqueous solution of ethanol with concentration (20 vol. %; 50 vol. %; 80 vol. % and 96 vol. %) and distilled water. The temperature was kept constant at 40oC.
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    EXTRACTION OF VALUABLE COMPONENTS FROM WINERY’S BY-PRODUCTS THROUGH SOXHLET EXTRACTION. EFFECT OF OPERATIONAL PARAMETERS ON PRODUCT YIELD AND QUALITY
    (2022-01-01) Radoeva R.; Karsheva M.; Enchev B.
    This study focuses on the Soxhlet extraction of pre-dried at 50oC grape marc and grape seeds from Mavrud grapes cultivated in 2016 and 2018. An investigation of total polyphenol contents (TPC), total anthocyanins (TA) and totalantioxidant capacity (TAC) was done. Soxhlet extraction takes place at a pre-selected duration of 180 minutes. Theeffect of the solid-to-liquid ratio was examined with 2 solvents: ethanol-in-water solution (50/50 vol.) and pure methanol.The temperature was kept constant at 220oC. The contents of obtained extracts were characterized by HPLC
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    POLYPHENOLS OF GRAPE POMACE FROM LOCAL BULGARIAN VARIETY MAVRUD. ANTIOXIDANT AND ANTITUMOR EFFECT AGAINST BREAST CANCER
    (2022-01-01) Radoeva R.; Yankova I.; Enchev B.; Karsheva M.; Ivanova E.; Iliev I.
    Grape pomace is the main by-product of winemaking, a valuable source of polyphenols with antimicrobial, antioxidant and anti-cancer effect. Grape seeds and marcs extracts are of strategic importance for the development of new therapeutic approaches against certain cancer diseases, including breast cancer. In this study the antioxidant and antitumor potential of the polyphenolic fraction of grape pomace obtained from the vinification of the local Bulgarian grape variety Mavrud is reported. After Soxhlet extraction with 50 % water solution of ethanol, the total polyphenol content of the extracts by the Folin-Ciocalteu colorimetric method was determined. The obtained extracts were characterized by HPLC-DAD and their antioxidant activity was studied with DPPH assay. The cytotoxic effect was tested on 3T3 cell line, while MCF-7 and MDA-MB-231 breast cancer cell lines were selected to determine antitumor activity. The results showed higher total polyphenol content in the marc compared to the seed extracts and prevalence of gallic acid, catechin and epigallocatechin. A correlation between antioxidant activity and total polyphenol content was established. The studied extracts had a low cytotoxic effect, as the seed extracts showed a stronger antitumor activity compared to the extracts of marcs and potential for treatment of luminal breast cancer.