Alžbeta Demianová

Mrs. Alžbeta Demianová

orcid

Research Focus & Metrics

Academic Career Length

7Years (2020-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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18 February 2020 in Journal of Environmental Science and Health, Part B
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Journal Article
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ABAlica Bobková
Alica Bobková
MHMarek Hudáček
Marek Hudáček
SJSilvia Jakabová
Silvia Jakabová
ĽBĽubomí­r Belej
Ľubomí­r Belej
MCMarcela Capcarová
Marcela Capcarová
ADAlžbeta Demianová
Alžbeta Demianová
The total polyphenolic content and the antioxidant activity have been analyzed in ground beans of green, light, medium and dark roasted coffee by UV-VIS spectrometry. Water coffee extracts showed the highest levels of polyphenols in green and light roasted coffees where the total polyphenolic content (TPC) ranged from 49.19 ± 0.70 to 74.05 ± 0.28 and from 59.79 ± 1.45 to 38.34 ± 1.26 g GAE.kg−1, respectively. In medium roast samples it ranged from 43.90 ± 3.07 to 74.05 ± 0.28g GAE.kg−1 and in dark roast from 37.44 ± 0.63 to 47.41 ± 0.69 g GAE.kg−1. The total antioxidant capacity (TAC) reached the highest values (DPPH inhibition ranging from 69.08 ± 1.33% to 78.55 ± 0.89%) in light roasted coffees. Dark roasted coffees showed both the lowest content of polyphenols as well as the total antioxidant capacity. In case of TPC, statistically significant differences (P˂0.001) have been identified between green coffee and other roasted degrees. Also, dark coffee showed statistically noticeable differences (P˂0.001) in TPC in relation to other roasted stages. Statistically important difference (P˂0.001) has been discovered between the total antioxidant capacity of dark roasted coffee and other roasting levels. The results demonstrated that roasting process affects both the oxidative activity as well as polyphenolic content.

8 April 2022 in Foods
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Journal Article
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ABAlica Bobková
Alica Bobková
KPKatarína Poláková
Katarína Poláková
ADAlžbeta Demianová
Alžbeta Demianová
ĽBĽubomí­r Belej
Ľubomí­r Belej
MBMarek Bobko
Marek Bobko
Dolores del CastilloDolores del Castillo
Dolores del Castillo
Nowadays, there is an increased interest in coffee derivatives (green beans, roasted beans, and coffee by-products (Cascara and Silverskin)) due to their particular chemical composition. This study aimed to compare the content of dry matter, total fat, fatty acids, and fiber (ADF, NDF) of coffee by-products (Cascara and Silverskin) and coffee beans (green and roasted under different conditions). Coffee beans and their by-products were obtained from 100% C. arabica coffee cherries from Panama by dry process. The lowest concentrations of fat corresponded to Cascara 4.24 g·kg−1 and Silverskin 23.70 g·kg−1, respectively. The major fatty acids detected in all samples were palmitic, stearic, oleic, and linoleic acids, the latter two being essential fatty acids. LDA showed that 89.01% of the variability between beans and by-products was explained by lignoceric, myristic, behenic, tricosanoic, arachidic, and heneicosanoic acids. Silverskin appeared to be a good source of lignoceric, myristic, and behenic acids and had a higher concentration of dietary fiber (314.95 g·kg−1) than Cascara (160.03 g·kg−1). Coffee by-products (Silverskin and Cascara) are low-fat products enriched in dietary fiber. Their incorporation, after adjustment, into the global diet may contribute to nutrition security, the sustainability of the coffee sector, and human health.

6 August 2021 in Foods
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Journal Article
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ABAlica Bobková
Alica Bobková
ADAlžbeta Demianová
Alžbeta Demianová
ĽBĽubomí­r Belej
Ľubomí­r Belej
ĽHĽuboš Harangozo
Ľuboš Harangozo
MBMarek Bobko
Marek Bobko
JÁJúlius Árvay
Július Árvay
Tea (Camellia sinensis) is widely sought for beverages worldwide. Heavy metals are often the main aims of the survey of teas, given that the use of agricultural fertilization is very frequent. Some of these may affect the content of bioactive compounds. Therefore, in this study, we analyzed fermented and non-fermented teas of a single plant origin from Japan, Nepal, Korea, and China, and described mutual correlations and changes in the total antioxidant capacity (TAC), and the content of polyphenols (TPC), caffeine, and heavy metals in tea leaves, in relation to the origin and fermentation process. Using UV-VIS spectrophotometry and HPLC-DAD, we determined variations in bioactive compounds’ content in relation to the fermentation process and origin and observed negative correlations between TAC and TPC. Heavy metal content followed this order: Mn > Fe > Cu > Zn > Ni > Cr > Pb > Co > Cd > Hg. Given the homogenous content of these elements in relation to fermentation, this paper also describes the possibility of using heavy metals as determinants of geographical origin. Linear Discriminant Analysis showed an accuracy of 75% for Ni, Co, Cd, Hg, and Pb, explaining 95.19% of the variability between geographical regions.

1 December 2021 in Foods
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Lukáš JurčagaLukáš Jurčaga
Lukáš Jurčaga
MBMarek Bobko
Marek Bobko
AKAdriana Kolesárová
Adriana Kolesárová
ABAlica Bobková
Alica Bobková
ADAlžbeta Demianová
Alžbeta Demianová
MČMatej Čech
Matej Čech
Oxidation is one of the most prevalent factors responsible for meat product deterioration. Due to their potential health risks, commonly used synthetic antioxidants are beginning to be frowned upon by customers. The industry is searching for a natural replacement. In our study, we incorporated blackcurrant (Ribes nigrum L.) and Kamchatka honeysuckle (Lonicera caerulea var. Kamtschatica) extracts into raw-cooked meat products (frankfurters) as natural antioxidants. We observed that both extracts at concentrations of 3 mL·kg−1 were able to significantly (α = 0.05) postpone lipid oxidation in our samples, with results comparable to vitamin C (0.5 mg·kg−1) addition. Moreover, we did not observe negative effects of the extracts on the product’s color, pH, or textural properties. Negative results were reported in the sensory evaluation of honeysuckle addition samples. This could have been caused by the natural strong and bitter taste of honeysuckle, which was transferred to the extracts and, subsequently, into the meat product.

11 July 2023 in Foods
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Journal Article
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KPKatarína Poláková
Katarína Poláková
ABAlica Bobková
Alica Bobková
ADAlžbeta Demianová
Alžbeta Demianová
MBMarek Bobko
Marek Bobko
Judita LidikovaJudita Lidikova
Judita Lidikova
TTTomáš TÓTH
Tomáš TÓTH
Coffee processing is a major contributor to the creation of food and product waste. Using coffee co-products can play an essential role in addressing environmental problems and issues with nutritionally unbalanced foods, population growth, and food-related diseases. This research aimed to determine the quality and sensory parameters (aw, pH, dry matter, TAC, TPC, fat, fatty acids profile, fiber, caffeine, chlorogenic acids, color, and sensory analysis) of different botanical origins of cascara (coffee husks) and silverskin (thin layer). The results of this study show that silverskin and cascara are a good source of TAC (1S 58.17 ± 1.28%, 2S 46.65 ± 1.20%, 1C 36.54 ± 1.84%, 2C 41.12 ± 2.11%). Cascara showed the presence of polyphenols (2C 49.135 g GAE·kg−1). Coffee co-products are good sources of fiber. Silverskin had higher values of caffeine than cascara. Palmitic, stearic, oleic, linoleic, and arachidic acids were the most represented acids in the samples. Given the obtained results, cascara can be considered “low-fat” (1C 4.240 g·kg−1 and 2C 5.4 g·kg−1). Based on the sensory evaluation, no sample reached the acceptable index value of 70%. Understanding the link between the character, identification properties, and composition of coffee co-products of different botanical origins can enable their application in the food industry.

13 January 2021 in International Journal of Food Engineering
Verified
Journal Article
Closed access
ABAlica Bobková
Alica Bobková
SJSilvia Jakabová
Silvia Jakabová
ĽBĽubomír Belej
Ľubomír Belej
LJLukáš Jurčaga
Lukáš Jurčaga
JČJozef Čapla
Jozef Čapla
ADAlžbeta Demianová
Alžbeta Demianová
This research was focused on the evaluation of selected parameters of coffee quality, regarding the beverage preparation method, using high-performance liquid chromatography. Samples of Coffea arabica from South America were analyzed. For the preparation of the final beverage were used filtration and moka methods. All samples roasted at medium dark roasting level Full City ++, contained less than 5% of moisture. The values of pH and dry matter content did not show a significant difference. The lowest content of chlorogenic acid reached value (1.41 g·100 g −1 ) prepared from filtration and 1.49 g·100 g −1 prepared from moka method. The highest content of chlorogenic acid ranged from 2.94 g. 100 g −1 filtration method and 3.36 g. 100 g −1 moka. Similarly, caffeine content, showed lower values using the filtration method. Values ranged from 1.37 to 1.57% (filtration) and from 1.54 to 1.78% (moka). However, PCA didn’t show a significant difference.