Jacek Wilczak

Dr. Jacek Wilczak


Research Focus & Metrics

Academic Career Length

27Years (2000-Present)

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

Representative Publications

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1 July 2001 in Nutrition
Verified
Journal Article
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EJEwa Jówko
Ewa Jówko
POPiotr Ostaszewski
Piotr Ostaszewski
MJMichal Jank
Michal Jank
JSJaroslaw Sacharuk
Jaroslaw Sacharuk
AZAgnieszka Zieniewicz
Agnieszka Zieniewicz
SNSteve Nissen
Steve Nissen

29 January 2010 in International Journal of Food Sciences and Nutrition
Verified
Journal Article
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PDF file
Piotr LatochaPiotr Latocha
Piotr Latocha
TKTomasz Krupa
Tomasz Krupa
RWRafał Wołosiak
Rafał Wołosiak
EWElwira Worobiej
Elwira Worobiej
JWJacek Wilczak
Jacek Wilczak
The present research aimed at evaluating the vitamin C, total phenolic content (TPC), phenolic compounds, carotenoids, and chlorophyll contents, as well as antioxidant activity (AAC) of six Actinidia species fruit. Vitamin C, phenolic compounds, carotenoids and chlorophylls were measured using high-performance liquid chromatography. TPC was determined using the Folin–Ciocalteau reagent, and AAC using 2,2-diphenyl-1-picryl hydrazyl (DPPH) assay. The highest concentrations of vitamin C and TPC were found for Actinidia kolomikta fruit (1008.3 and 634.1 mg/100 g fresh weight [FW], respectively). Among phenolic compounds, seven phenolic acids and three flavonoids were identified. The 2,5-dihydroxybenzoic acid prevailed in A. kolomikta (425.54 mg/100 g FW), while tannic acid dominated in other species (4.63–100.43 mg/100 g FW). The largest amounts of chlorophylls and carotenoids were identified as Actinidia macrosperma (4.02 and 2.09 mg/100 g FW, respectively). The AAC of fruit extracts decreased in the order of A. kolomikta > Actinidia purpurea > Actinidia melanandra > A. macrosperma > Actinidia arguta > Actinidia deliciosa according to the DPPH assay.

1 October 2015 in Food Hydrocolloids
Verified
Journal Article
Closed access
KBKatarzyna Błaszczyk
Katarzyna Błaszczyk
JWJacek Wilczak
Jacek Wilczak
Joanna HarasymJoanna Harasym
Joanna Harasym
SGSylwia Gudej
Sylwia Gudej
DSDominika Suchecka
Dominika Suchecka
Joanna Gromadzka-OstrowskaJoanna Gromadzka-Ostrowska
Joanna Gromadzka-Ostrowska

2 December 2014 in Food & Function
Verified
Journal Article
Closed access
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JWJacek Wilczak
Jacek Wilczak
KBKatarzyna Błaszczyk
Katarzyna Błaszczyk
DKDariusz Kamola
Dariusz Kamola
MGMałgorzata Gajewska
Małgorzata Gajewska
Joanna HarasymJoanna Harasym
Joanna Harasym
Joanna Gromadzka-OstrowskaJoanna Gromadzka-Ostrowska
Joanna Gromadzka-Ostrowska
Purpose: The aim of the study was to investigate the protective effect of low and high molecular weight beta-glucans on the chosen immunological parameters, markers of antioxidative potential in rats’ colon tissue, the number of lactic acid bacteria (LAB) and the concentration of short-chain fatty acids (SCFA) in rats’ faeces. Methods: The experiment was carried out on 72 8-week old male Sprague–Dawley rats: control (n = 36) and experimental (n = 36). In half of the animals from each group enteritis was induced by LPS (10 mg kg−1). Rats from the experimental group were divided into two groups receiving high (GI) or low (GII) molecular weight beta-glucans for 6 consecutive weeks. Results: LPS evoked enteritis in all the treated animals, manifested by changes in the levels of IL-10, IL-12 and TNF-alpha, as well as in the number of intraepithelial lymphocytes (IELs) and lamina propria lymphocytes (LPLs) in the colon tissue. Dietary supplementation with beta-glucans following LPS treatment partially reversed this effect. The changes in SCFA concentration were noted, indicating an improvement of the fermentation process in the colon. This effect coincided with an increased number of LAB, pointing at the prebiotic properties of beta-glucans. The positive influence of beta-glucans was also manifested by the improved values of antioxidative potential markers (TAS, SOD, GR and GPx activity, TBARS concentration), noted especially in rats with LPS-induced enteritis. This influence was more pronounced in the case of low molecular weight oat beta-glucan (GII). Conclusions: The present study showed a positive effect of beta-glucans, especially the low molecular weight form, on the colon tissue of healthy rats, as well as animals with LPS-induced enteritis.

1 December 2012 in International Journal of Sport Nutrition and Exercise Metabolism
Verified
Journal Article
Closed access
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EJEwa Jówko
Ewa Jówko
JSJaroslaw Sacharuk
Jaroslaw Sacharuk
BBBozena Balasinska
Bozena Balasinska
JWJacek Wilczak
Jacek Wilczak
MCMalgorzata Charmas
Malgorzata Charmas
RCRobert Charmas
Robert Charmas
Purpose: To evaluate the effect of acute ingestion of green tea polyphenols (GTP) on blood markers of oxidative stress and muscle damage in soccer players exposed to intense exercise.Methods: This randomized, double-blinded study was conducted on 16 players during a general preparation period, when all athletes participated in a strength-training program focused on the development of strength endurance. After ingestion of a single dose of GTP (640 mg) or placebo, all athletes performed an intense muscle-endurance test consisting of 3 sets of 2 strength exercises (bench press, back squat) performed to exhaustion, with a load at 60% 1-repetition maximum and 1-min rests between sets. Blood samples were collected preexercise, 5 min after the muscle-endurance test, and after 24 hr of recovery. Blood plasma was analyzed for the concentrations of thiobarbituric acid–reacting substances (TBARS), uric acid (UA), total catechins, total antioxidant status (TAS), and activity of creatine kinase (CK); at the same time, erythrocytes were assayed for the activity of superoxide dismutase (SOD).Results: In both groups, plasma TBARS, UA, and TAS increased significantly postexercise and remained elevated after a 24-hr recovery period. SOD activity in erythrocytes did not change significantly in response to the muscle-endurance test, whereas in both groups plasma CK activity increased significantly after 24 hr of recovery. Acute intake of GTP cased a slight but significant increase in total plasma catechins. However, GTP was found not to exert a significant effect on measured parameters.Conclusions: Acute ingestion of GTP (640 mg) does not attenuate exercise-induced oxidative stress and muscle damage.

1 April 2015 in Journal of Functional Foods
Verified
Journal Article
Closed access
DSD. Suchecka
D. Suchecka
Joanna HarasymJoanna Harasym
Joanna Harasym
JWJacek Wilczak
Jacek Wilczak
MGMałgorzata Gajewska
Małgorzata Gajewska
Michał OczkowskiMichał Oczkowski
Michał Oczkowski
Joanna Gromadzka-OstrowskaJoanna Gromadzka-Ostrowska
Joanna Gromadzka-Ostrowska