Jakub Roman Królak

Mr. Jakub Roman Królak

Faculty Of Food Science And Nutrition, Poznań university of life sciences, Poznań, Wielkopolskie, Poland
orcid
PhD student

Research Focus & Metrics

Academic Career Length

4Years (2023-Present)

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

Representative Publications

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8 July 2024 in Foods
Verified
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NČNatália Čmiková
Natália Čmiková
Przemysław Łukasz KowalczewskiPrzemysław Łukasz Kowalczewski
Przemysław Łukasz Kowalczewski
Dominik KmiecikDominik Kmiecik
Dominik Kmiecik
ATAneta Tomczak
Aneta Tomczak
ADAgnieszka Drożdżyńska
Agnieszka Drożdżyńska
Miroslava KačániováMiroslava Kačániová
Miroslava Kačániová
Microalgae are exceptional organisms from a nutritional perspective, boasting an array of bioactive compounds that have long justified their incorporation into human diets. In this study, we explored the potential of five microalgae species: Nannochloropsis sp., Tetraselmis chuii, Chaetoceros muelleri, Thalassiosira weissflogii, and Tisochrysis lutea. We conducted comprehensive analyses of their nutritional profiles, encompassing protein content, individual amino acid composition, mineral and trace element levels, fatty acid profiles (including saturated fatty acids (SFAs), monounsaturated fatty acids (MUFAs), and polyunsaturated fatty acids (PUFAs)), polyphenol compositions, and vitamin B content. The antioxidant activity of the ethanolic extracts was evaluated using two methods: ABTS and DPPH radical scavenging assay. The total protein content of the microalgae ranged from 34.09 ± 0.39% to 42.45 ± 0.18%, with the highest concentration observed in T. weissflogii. Essential amino acids such as histidine, threonine, lysine, valine, isoleucine, leucine, phenylalanine, and methionine were present in concentrations ranging from 0.53 ± 0.02 to 12.55 ± 2.21 g/16 g N. Glutamic acid emerged as the most abundant amino acid, with concentrations ranging from 6.73 ± 0.82 to 12.55 ± 2.21 g/16 g N. Among the microalgae species, T. chuii exhibited the highest concentrations of calcium (Ca) and manganese (Mn), while C. muelleri showed prominence in magnesium (Mg), sodium (Na), and iron (Fe). T. weissflogii stood out for its potassium (K) content, and T. lutea contained notable amounts of copper (Cu), zinc (Zn), and lead (Pb). Regarding fatty acid profiles, Nannochloropsis sp. and T. chuii were predominantly composed of SFA, while C. muelleri and T. weissflogii were rich in MUFA. PUFAs dominated the fatty acid profile of T. lutea, which also exhibited the most diverse range of polyphenolic substances. We also analyzed the B vitamin content, with T. lutea displaying the highest concentrations of niacin (B3) and riboflavin (B2). Antioxidant activity was confirmed for all microalgae tested using DPPH and ABTS radical IC50 (mg/mL) converted to Trolox equivalent (TEAC). These findings underscore the substantial potential of the examined microalgae species as sources of biologically valuable substances characterized by rapid growth and relatively undemanding cultivation conditions.

1 January 2025 in Open Chemistry
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NČNatália Čmiková
Natália Čmiková
Przemysław Łukasz KowalczewskiPrzemysław Łukasz Kowalczewski
Przemysław Łukasz Kowalczewski
Dominik KmiecikDominik Kmiecik
Dominik Kmiecik
Piotr KlimowiczPiotr Klimowicz
Piotr Klimowicz
ADAgnieszka Drożdżyńska
Agnieszka Drożdżyńska
Miroslava KačániováMiroslava Kačániová
Miroslava Kačániová
The rising incidence of chronic diseases has spurred interest in functional foods rich in antioxidants and essential nutrients, as well as in exploring their potential cytotoxic activity against cancer cells. This study aims to address this gap by providing a comprehensive comparison of their biochemical composition and bioactive properties, offering insights into their targeted applications in functional foods and supplements. This study investigated the nutritional composition and bioactive properties of two algae species, chlorella ( Chlorella vulgaris ) and spirulina ( Arthrospira platensis ). Analysis included total protein content, amino acid profiles, mineral compositions, fatty acid profiles, B vitamin contents, polyphenol profiles, carotenoid contents, antioxidant activities (DPPH˙ and ABTS + assays), and cytotoxic activities. Chlorella exhibited higher protein content (64.63%) compared to spirulina (58.24%). Spirulina showed higher concentrations of non-essential and essential amino acids, except for methionine. Mineral analysis revealed spirulina’s superiority in calcium, potassium, sodium, iron, manganese, and zinc, whereas chlorella contained higher copper and lead levels. Fatty acid analysis indicated chlorella’s dominance in saturated fatty acids, while spirulina showed higher proportions of monounsaturated and polyunsaturated fatty acids. Polyphenol analysis highlighted chlorella’s higher levels of p -hydroxybenzoic acid, whereas spirulina contained more rutin and catechin. Chlorella also exhibited higher levels of niacin and riboflavin compared to spirulina. Additionally, spirulina extracts, whether ethanolic or hexane-based, demonstrate substantial antioxidant effects, as evidenced by their lower IC 50 values in both DPPH˙ and ABTS + assays relative to chlorella. Overall, spirulina showed superior antioxidant effect. Chlorella hexane extract showed slightly higher cytotoxic potential compared to spirulina. These findings enhance our understanding of the nutritional and health-promoting properties of chlorella and spirulina, suggesting their potential applications in functional foods and dietary supplements. While in vitro assays indicate promising bioactivity, future studies should include in vivo experiments to confirm the health benefits and functional applications of these microalgae.

22 March 2023 in Applied Sciences
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Maria Barbara RóżańskaMaria Barbara Różańska
Maria Barbara Różańska
PKPatrycja Kokolus
Patrycja Kokolus
Jakub Roman KrólakJakub Roman Królak
Jakub Roman Królak
PJPatrycja Jankowska
Patrycja Jankowska
AOAgata Osoś
Agata Osoś
Sylwia Mildner-SzkudlarzSylwia Mildner-Szkudlarz
Sylwia Mildner-Szkudlarz
The present study aimed to evaluate the effect of the extrusion process and particle size on the properties of rice flour (microstructure, pasting properties), gluten-free dough (rheological properties), and bread (texture, specific volume, water absorption capacity, low-field nuclear magnetic resonance (LF NMR) relaxometry). Rice flours were extruded at 80 and 120 °C with feed moisture (15 and 30%) and with the same particle size (132–200 µm). Significant differences were observed between the pasting profiles of the flours before and after extrusion. The pasting profile of extruded flours confirmed that hydrothermal treatment partially gelatinized the starch, decreasing the viscosity during heating. The water binding properties increased with the extrusion temperature and moisture content and also with the particle size of the flour. The most important parameter influencing the mechanical properties of the dough was the moisture content of the flour and significant differences were observed between fine (132–200 μm). The molecular dynamics of particles containing protons in the bound and bulk fractions in each sample do not depend on the extruder parameters or granulation of the obtained fraction. LF NMR results confirmed that extrusion of rice flour led to a significant decrease in the T21 value compared to the control sample and an increase in the T22 value in breads made with flours with particle size <132 μm. A linear relationship was found between the spin-spin relaxation times (T1) changes and the equilibrium water activity (ar). The results showed that bread with extruded rice flour at the same die temperature resulted in a significantly higher bread volume (31%) and lower hardness (27%) compared to the control. The highest hardness was observed in the case of samples prepared with extruded flour with the addition of 15% moisture, regardless of temperature and particle size.

30 May 2025 in Foods
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Jakub Roman KrólakJakub Roman Królak
Jakub Roman Królak
JKJan Jakub Kucharski
Jan Jakub Kucharski
Przemysław Łukasz KowalczewskiPrzemysław Łukasz Kowalczewski
Przemysław Łukasz Kowalczewski
KKlaudia Magdalena Dudek
Klaudia Magdalena Dudek
MRMillena Ruszkowska
Millena Ruszkowska
HBHanna Maria Baranowska
Hanna Maria Baranowska
The increasing demand for diverse foods and tailored nutrition encourages the development of innovative products, such as bread enriched with cricket powder (CP) or potato protein (PP). This study presents the preparation and analysis of gluten-free breads with CP and PP, focusing on their nutritional value and physical properties. Analytical methods included water activity measurement, bread volume, crumb color analysis, FTIR spectroscopy, low-field NMR relaxometry, and texture profile analysis. Ash content ranged from 0.60 ± 0.03% to 1.16 ± 0.11%, and caloric values ranged from 216.2 to 229.5 kcal/100 g. Water activity remained stable across all samples (0.975–0.976). Crumb color analysis showed the greatest change in CP samples (ΔE = 14.07), while PP had minimal impact (ΔE = 2.15). FTIR spectra revealed increased amide I and II bands, indicating higher protein content. NMR results demonstrated shorter T1, T21, and T22 times for CP, suggesting reduced water mobility and a denser structure, while PP samples showed higher values, indicating a looser, more hydrated matrix. Texture analysis confirmed that CP increased firmness and compactness, whereas PP enhanced springiness. These findings suggest that CP and PP can improve the nutritional and structural properties of gluten-free bread, offering valuable alternatives for modern dietary needs.

20 December 2025 in Molecules
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Jakub Roman KrólakJakub Roman Królak
Jakub Roman Królak
Agnieszka MakowskaAgnieszka Makowska
Agnieszka Makowska
KWKatarzyna Waszkowiak
Katarzyna Waszkowiak
KMKamila Myszka
Kamila Myszka
KSKinga Stuper-Szablewska
Kinga Stuper-Szablewska
KRKatarzyna Rzyska-Szczupak
Katarzyna Rzyska-Szczupak
This study aimed to determine the effect of lactic acid fermentation with Lactiplantibacillus plantarum on the bioactive compound composition and fatty acid profile of black cumin, camelina, milk thistle, and evening primrose cakes, as well as to evaluate their application as ingredients in wheat bread production (9% of wheat flour substitution). Fermentation increased the content of flavonoids and phenolic acids in camelina cake by approximately 30%, while causing a 30% decrease in carotenoid content. In black cumin cake, an eightfold increase in 4-hydroxybenzoic acid content and a 10% reduction in thymoquinone were observed. For milk thistle, silymarin content decreased by approximately 10%. Fermentation increased the proportion of saturated fatty acids (SFAs) and monounsaturated fatty acids (MUFAs), reducing polyunsaturated fatty acids (PUFAs) in all analyzed cakes. Breads containing 9% fermented cakes exhibited lower specific volume and greater hardness (22–80%), gumminess (17–64%), and chewiness (8–48%), compared to the breads with unfermented cakes. The contents of bioactive compounds in breads depended on the type of cake added. The bread with fermented camelina cake showed a 15% increase in flavonoid content and higher levels of selected phenolic acids compared to the bread with unfermented camelina. The breads containing camelina cake, both fermented and unfermented, also had the most favorable physical quality (texture and volume). The amount of ferulic acid in all samples of bread with the addition of fermented cakes was lower in comparison to the bread samples with unfermented cakes.